开云体育

First - This will be my last post to the group. Yahoo seems determined to get in on the Facebook type market, and frankly, I'm just not sociable enough for that. I don't twitter, I don't Facebook, I don't mySpace, etc.
I've decided I don't Yahoo either. I intend to delete this Yahoo account once this is posted, so will not see any responses or questions. Sorry if that seems abrupt, but once I make a decision, it instantly gets applied. This is my attempt at a parting gift, not a slap in the face, hopefully...

The schematic -

The revised schematic came from a weekend of tests done by a very well regarded professional in the field, and he has the equipment to do it too. He is under contract so he can't publish this. He did me a favor.

You'll note that this is similar to other versions, but the driver phasing is critical, and all of the versions we've seen seem to have been redrawn, redrawn, and redrawn, with errors at each revision..

You'll note I just re worked an earlier crossover, but removed the confusing wire colors, and put in the revised polarities. On the wire colors, well... Dahlquist had some one color scheme, others another color scheme, and some were all white wires! Get an ohm meter and trace polarities to the next component on the crossover. It's the only way to KNOW you have it per the schematic.

In brief, the DQ10 crossover is 2 series crossovers, in parallel. A third leg added for the super tweeter. The low end of each driver is electrically a second order rolloff. The high end is electrically a first order rolloff. So, it an asymmetrical crossover which is common enough.

The phasing on most symmetrical 12 db/octave, aka second order filters is usually reverse phased at the crossover points. From what I've read, it shouldn't matter whether the crossover is series or parallel. That's not necessarily true though as series first order can also be reconfigured to quasi-second order which has NO phase shift, although still doesn't attenuate very well. Then a second component could be tweaked in to help protect a delicate mid or tweeter...? I know Paul W. Klipsch did things like that!

Reversing 1 driver puts the drivers IN PHASE at the crossover points, because each section is 90 degree's shifted, so 90 degree's + 90 degree's = 180 degree's, or completely reversed. This will usually cause a null at the crossover frequency, unless the driver phasing is reversed on 1 of the drivers, usually the tweeter.

DQ-10's are not symmetrical second order, so the phase shift here is only 135 degree's(ignoring the actual phase shift of the drivers themselves...) These are not "book" crossovers at all, but rather crossovers designed from IN FRONT of the speaker, testing each element, and each change. This is 100% counter to the way systems are designed today. Today, it's all modeled on computers, then revised and optimized by computers. Then, maybe if if it's a really expensive system, some one actually sits in front of it and listens. Maybe he'll even tweak it a little. Jon Dahlquist was brilliant!

What jk determined is that from a distance of 40", and with the microphone mounted and aimed towards the middle of the top array, the drivers were all IN Phase at the crossover frequency's, and for a good range beyond with the phasing per the revised schematic.. The frequency response was also much smoother, both on and off axis.

It seemed to him, this had to be the ORIGINAL layout, unless the idea was to have a more diffuse sound-field, and the speakers were required to be listened to well off axis. We tried it that way, and it made for a much BIGGER image. However, it seems unlikely that was the intent of the ORIGINAL designer. Recall, this was touted as a PHASED ARRAY, with the drivers acoustic centers all critically aligned and focused.

We were both flabbergasted when we heard them! For me, it was a trip down memory lane, back to the early 70's. This was the sound I remembered and fell in love with. Absolute precision! I'd forgotten they could sound that good. The detailing, even in the mid range was equal to, or superior to many single panel speakers, i.e. electrostatics, ribbons, etc.

The highs are still a little harsh, a little rough, but a slight adjustment of the HI-trim pot helped a lot. It's remains a good high end, not the best, not perfect, but quite good.

Try it; don't try it....it's up to you. Maybe yours are already wired this way?

Parting shots, and a carrot -

First, and hopefully I'm not biting the hand that feeds, I am NOT a fan of a certain NY based repair center which has been around for quite some time. Despite their claims, I'm convinced they don't have a clue. For example - The "replacement DQ-10 tweeter" they charge an arm and a leg for, mounted to the cheapest thinnest piece of flakeboard I've ever seen is Wrong, wrong WRONG! It's an 8 OHM(!!!) tweeter, made by Eton (SD19) This is a fine tweeter BTW, but it will not work properly with a crossover which was designed for a 4 ohm tweeter. Even car audio people know better!
It would be much better in the DQ-20 series, having similar specs, to the scanspeak D-2008/2010's although it has a bit higher FS.
Their woofer re builds are over priced, and the're many outfits which will rebuild, re cone, re magnetise Advent 10" woofers in any case, and for a better price with equal or superior results.
Their grill cloth is questionable, too. You'd be better off with thin double knit polyester available in a variety of colors from any fabric store. It s-t-r-e-t-c-h-e-s like crazy and is all but invisible to the ear. It's also pennies on the dollar for what they charge. The stuff they sell IS NOT original, as that cloth hasn't been made it a long time. So, save some bucks.

I'm not a fan of the designer capacitor "upgrades" of the week either. Side by side, stock to re done, there is little difference, let alone improvement - but then again, it's a hobby, so enjoy it as you see fit. Just make sure you get the values right by measuring the parts yourself, AND don't swap in lower resistance inductors unless you realize that the series resistance of a choke IS part of the design of the crossover, and bass tuning.... You'll need to add resistance to keep it balanced, and then, what's the point? These coils won't saturate at the power levels that the drivers can tolerate.

The carrot - I have accumulated so much information on Dahlquist speakers, specifically the DQ-20 series, and the DQ-10's. It seems a shame to just let it go to waste, Even for those who disagree with my views, which is all they can truly be called, as I'm not the designer and can't really know; it can still be a second view, perhaps an antitheses to another thesis? Will synthesis result?

So, at some point in time I hope to post it all on the internet, along with pictures of how to put fresh surrounds on the mid range drivers with the most successful technique, testing of the crossover parts, rebuilding, replacement drivers and the mods for making them work, etc.

Just search the internet and you'll be sure to find it. Maybe 6 months, maybe a year, maybe ??? This would not be a money making venture, It would be just for fun, and a distraction from work pressures. Any/all welcome to use whatever. Assuming I ever put it together.

My apology's for the long post, but I felt this was unfinished business. Thanks to the moderators. They did the right thing in creating the group and it's been a great resource for many, even those not part of the group. I like how they stay out of it and let us shoot ourselves in the foot. With so many groups, it seems the moderators have an agenda, or at the least are on a power trip. Well done, whoever you are.. Thank you.

Best regards to all. Don't let anyone tell you Dahlquists are an old MID-FI design(I saw that on a site recently). They probably heard a poorly wired or hacked set, or they just can't hear at all.

This was quality American made gear. keep it going!

--- In Dahlquist@..., "audio4antiques" <clydeblair@> wrote:

I'm sorry to see a contributor like planarguy leave, but he must have had a compelling reason.
First, I make no claim to be a professional crossover designer or analyst. Remembering that reverse engineering a crossover is just a crap-shoot, here's my take on the complex and mystifying DQ-10 crossover configuration. It is more than it appears. Agreed that it is ostensibly two series sections in parallel.
STAGE 1: The woofer/midwoofer (aka stage 1) has 8 ohms (R1/R1b) across the woofer Re of approx 4 ohms for an effective Re of 2.67, an apparent bass boost in response to criticism of weak bass. L2 then rolls the woofer off at 334hz. R2 added to the midwoofer Re of approx 8 ohms for an effective 12 ohms with C1 rolls it off at 165hz and should be 40uf to match up with the woofer rolloff. L1 correctly rolls the midwoofer off at approx 1503hz to the mid dome.
STAGE 2: C2 and L3 form an embedded 12db/oct parallel section. L3 correctly does its job at approx 1432hz but based on this observation C2 should be 8uf. L3 sees an Re of 3.6 ohms but C2 sees 9 ohms with R3 in series. Possibly a calculation error. For the mid dome/tweeter layout, if the intent was a quasi 12/db/.7 Zeta layout, C3 and L4 are close to being spot on. However, I don't understand redundant C6 that would also yield a 5349 hz rolloff. C4, C5 and R5 must be a tweeter smoothing circuit. Maybe scrutiny with an oscilloscope would explain it all.
Viewed as two 2-way crossovers, the woofer and mid dome in positive polarity and the mid woofer and tweeter in reverse polarity make sense. But they ARE integrated, so I think that the midwoofer should be in positive polarity and the mid dome in reverse polarity. My DQ-10s are deinstalled right now, so when I have the time I'm going to implement these changes and see what shakes out.

--- In Dahlquist@..., "planarguy" <planarguy@> wrote:

First - This will be my last post to the group. Yahoo seems determined to get in on the Facebook type market, and frankly, I'm just not sociable enough for that. I don't twitter, I don't Facebook, I don't mySpace, etc.
I've decided I don't Yahoo either. I intend to delete this Yahoo account once this is posted, so will not see any responses or questions. Sorry if that seems abrupt, but once I make a decision, it instantly gets applied. This is my attempt at a parting gift, not a slap in the face, hopefully...

The schematic -

The revised schematic came from a weekend of tests done by a very well regarded professional in the field, and he has the equipment to do it too. He is under contract so he can't publish this. He did me a favor.

You'll note that this is similar to other versions, but the driver phasing is critical, and all of the versions we've seen seem to have been redrawn, redrawn, and redrawn, with errors at each revision..

You'll note I just re worked an earlier crossover, but removed the confusing wire colors, and put in the revised polarities. On the wire colors, well... Dahlquist had some one color scheme, others another color scheme, and some were all white wires! Get an ohm meter and trace polarities to the next component on the crossover. It's the only way to KNOW you have it per the schematic.

In brief, the DQ10 crossover is 2 series crossovers, in parallel. A third leg added for the super tweeter. The low end of each driver is electrically a second order rolloff. The high end is electrically a first order rolloff. So, it an asymmetrical crossover which is common enough.

The phasing on most symmetrical 12 db/octave, aka second order filters is usually reverse phased at the crossover points. From what I've read, it shouldn't matter whether the crossover is series or parallel. That's not necessarily true though as series first order can also be reconfigured to quasi-second order which has NO phase shift, although still doesn't attenuate very well. Then a second component could be tweaked in to help protect a delicate mid or tweeter...? I know Paul W. Klipsch did things like that!

Reversing 1 driver puts the drivers IN PHASE at the crossover points, because each section is 90 degree's shifted, so 90 degree's + 90 degree's = 180 degree's, or completely reversed. This will usually cause a null at the crossover frequency, unless the driver phasing is reversed on 1 of the drivers, usually the tweeter.

DQ-10's are not symmetrical second order, so the phase shift here is only 135 degree's(ignoring the actual phase shift of the drivers themselves...) These are not "book" crossovers at all, but rather crossovers designed from IN FRONT of the speaker, testing each element, and each change. This is 100% counter to the way systems are designed today. Today, it's all modeled on computers, then revised and optimized by computers. Then, maybe if if it's a really expensive system, some one actually sits in front of it and listens. Maybe he'll even tweak it a little. Jon Dahlquist was brilliant!

What jk determined is that from a distance of 40", and with the microphone mounted and aimed towards the middle of the top array, the drivers were all IN Phase at the crossover frequency's, and for a good range beyond with the phasing per the revised schematic.. The frequency response was also much smoother, both on and off axis.

It seemed to him, this had to be the ORIGINAL layout, unless the idea was to have a more diffuse sound-field, and the speakers were required to be listened to well off axis. We tried it that way, and it made for a much BIGGER image. However, it seems unlikely that was the intent of the ORIGINAL designer. Recall, this was touted as a PHASED ARRAY, with the drivers acoustic centers all critically aligned and focused.

We were both flabbergasted when we heard them! For me, it was a trip down memory lane, back to the early 70's. This was the sound I remembered and fell in love with. Absolute precision! I'd forgotten they could sound that good. The detailing, even in the mid range was equal to, or superior to many single panel speakers, i.e. electrostatics, ribbons, etc.

The highs are still a little harsh, a little rough, but a slight adjustment of the HI-trim pot helped a lot. It's remains a good high end, not the best, not perfect, but quite good.

Try it; don't try it....it's up to you. Maybe yours are already wired this way?

Parting shots, and a carrot -

First, and hopefully I'm not biting the hand that feeds, I am NOT a fan of a certain NY based repair center which has been around for quite some time. Despite their claims, I'm convinced they don't have a clue. For example - The "replacement DQ-10 tweeter" they charge an arm and a leg for, mounted to the cheapest thinnest piece of flakeboard I've ever seen is Wrong, wrong WRONG! It's an 8 OHM(!!!) tweeter, made by Eton (SD19) This is a fine tweeter BTW, but it will not work properly with a crossover which was designed for a 4 ohm tweeter. Even car audio people know better!
It would be much better in the DQ-20 series, having similar specs, to the scanspeak D-2008/2010's although it has a bit higher FS.
Their woofer re builds are over priced, and the're many outfits which will rebuild, re cone, re magnetise Advent 10" woofers in any case, and for a better price with equal or superior results.
Their grill cloth is questionable, too. You'd be better off with thin double knit polyester available in a variety of colors from any fabric store. It s-t-r-e-t-c-h-e-s like crazy and is all but invisible to the ear. It's also pennies on the dollar for what they charge. The stuff they sell IS NOT original, as that cloth hasn't been made it a long time. So, save some bucks.

I'm not a fan of the designer capacitor "upgrades" of the week either. Side by side, stock to re done, there is little difference, let alone improvement - but then again, it's a hobby, so enjoy it as you see fit. Just make sure you get the values right by measuring the parts yourself, AND don't swap in lower resistance inductors unless you realize that the series resistance of a choke IS part of the design of the crossover, and bass tuning.... You'll need to add resistance to keep it balanced, and then, what's the point? These coils won't saturate at the power levels that the drivers can tolerate.

The carrot - I have accumulated so much information on Dahlquist speakers, specifically the DQ-20 series, and the DQ-10's. It seems a shame to just let it go to waste, Even for those who disagree with my views, which is all they can truly be called, as I'm not the designer and can't really know; it can still be a second view, perhaps an antitheses to another thesis? Will synthesis result?

So, at some point in time I hope to post it all on the internet, along with pictures of how to put fresh surrounds on the mid range drivers with the most successful technique, testing of the crossover parts, rebuilding, replacement drivers and the mods for making them work, etc.

Just search the internet and you'll be sure to find it. Maybe 6 months, maybe a year, maybe ??? This would not be a money making venture, It would be just for fun, and a distraction from work pressures. Any/all welcome to use whatever. Assuming I ever put it together.

My apology's for the long post, but I felt this was unfinished business. Thanks to the moderators. They did the right thing in creating the group and it's been a great resource for many, even those not part of the group. I like how they stay out of it and let us shoot ourselves in the foot. With so many groups, it seems the moderators have an agenda, or at the least are on a power trip. Well done, whoever you are.. Thank you.

Best regards to all. Don't let anyone tell you Dahlquists are an old MID-FI design(I saw that on a site recently). They probably heard a poorly wired or hacked set, or they just can't hear at all.

This was quality American made gear. keep it going!

I'm sorry to see planar guy go too. Audio4antiques raises some interesting points. I am wondering if the crossover points he posts were calculated using the "nominal" impedance of each driver? As I'm sure most know, the capacitor value must be set for the actual driver impedance at the desired crossover point. I'm pretty sure Jon knew what those were.

I'm going to go back and re-verify the schematic I posted, but this emphasizes that it is necessary to state what serial number unit has been examined. Mine are early and I am sure more tweaking was done to them as production rolled on.

What is really needed is for a recapped DQ-10 to be measured using current gear to observed the overall response, including phase distribution and waterfall plots.

I used the driver Re measured with Woofer Tester which is:
Woofer=3.962
Midbass=6.94
Mid Dome=3.594
Tweeter=3.539
The algorithms I used were:
Zeta 1 - L=159.155*Re/Fc, C=159155/Re*Fc
Zeta .7 - L=(159.155*Re/Fc)*.7, C=(159155/Re*Fc)*1.414
12db parallel - L=318.3*Re/Fc, C=79577/Re*Fc
There's of course a fair amount of interpolation and guess work involved in reverse engineering a design and trying to read someone else's mind, and listening tests can throw calculated values out the window.

--- In Dahlquist@..., "Abner" <fauborgflorida@> wrote:

--- In Dahlquist@..., "audio4antiques" <clydeblair@> wrote:

I'm sorry to see a contributor like planarguy leave, but he must have had a compelling reason.
First, I make no claim to be a professional crossover designer or analyst. Remembering that reverse engineering a crossover is just a crap-shoot, here's my take on the complex and mystifying DQ-10 crossover configuration. It is more than it appears. Agreed that it is ostensibly two series sections in parallel.
STAGE 1: The woofer/midwoofer (aka stage 1) has 8 ohms (R1/R1b) across the woofer Re of approx 4 ohms for an effective Re of 2.67, an apparent bass boost in response to criticism of weak bass. L2 then rolls the woofer off at 334hz. R2 added to the midwoofer Re of approx 8 ohms for an effective 12 ohms with C1 rolls it off at 165hz and should be 40uf to match up with the woofer rolloff. L1 correctly rolls the midwoofer off at approx 1503hz to the mid dome.
STAGE 2: C2 and L3 form an embedded 12db/oct parallel section. L3 correctly does its job at approx 1432hz but based on this observation C2 should be 8uf. L3 sees an Re of 3.6 ohms but C2 sees 9 ohms with R3 in series. Possibly a calculation error. For the mid dome/tweeter layout, if the intent was a quasi 12/db/.7 Zeta layout, C3 and L4 are close to being spot on. However, I don't understand redundant C6 that would also yield a 5349 hz rolloff. C4, C5 and R5 must be a tweeter smoothing circuit. Maybe scrutiny with an oscilloscope would explain it all.
Viewed as two 2-way crossovers, the woofer and mid dome in positive polarity and the mid woofer and tweeter in reverse polarity make sense. But they ARE integrated, so I think that the midwoofer should be in positive polarity and the mid dome in reverse polarity. My DQ-10s are deinstalled right now, so when I have the time I'm going to implement these changes and see what shakes out.

--- In Dahlquist@..., "planarguy" <planarguy@> wrote:

First - This will be my last post to the group. Yahoo seems determined to get in on the Facebook type market, and frankly, I'm just not sociable enough for that. I don't twitter, I don't Facebook, I don't mySpace, etc.
I've decided I don't Yahoo either. I intend to delete this Yahoo account once this is posted, so will not see any responses or questions. Sorry if that seems abrupt, but once I make a decision, it instantly gets applied. This is my attempt at a parting gift, not a slap in the face, hopefully...

The schematic -

The revised schematic came from a weekend of tests done by a very well regarded professional in the field, and he has the equipment to do it too. He is under contract so he can't publish this. He did me a favor.

You'll note that this is similar to other versions, but the driver phasing is critical, and all of the versions we've seen seem to have been redrawn, redrawn, and redrawn, with errors at each revision..

You'll note I just re worked an earlier crossover, but removed the confusing wire colors, and put in the revised polarities. On the wire colors, well... Dahlquist had some one color scheme, others another color scheme, and some were all white wires! Get an ohm meter and trace polarities to the next component on the crossover. It's the only way to KNOW you have it per the schematic.

In brief, the DQ10 crossover is 2 series crossovers, in parallel. A third leg added for the super tweeter. The low end of each driver is electrically a second order rolloff. The high end is electrically a first order rolloff. So, it an asymmetrical crossover which is common enough.

The phasing on most symmetrical 12 db/octave, aka second order filters is usually reverse phased at the crossover points. From what I've read, it shouldn't matter whether the crossover is series or parallel. That's not necessarily true though as series first order can also be reconfigured to quasi-second order which has NO phase shift, although still doesn't attenuate very well. Then a second component could be tweaked in to help protect a delicate mid or tweeter...? I know Paul W. Klipsch did things like that!

Reversing 1 driver puts the drivers IN PHASE at the crossover points, because each section is 90 degree's shifted, so 90 degree's + 90 degree's = 180 degree's, or completely reversed. This will usually cause a null at the crossover frequency, unless the driver phasing is reversed on 1 of the drivers, usually the tweeter.

DQ-10's are not symmetrical second order, so the phase shift here is only 135 degree's(ignoring the actual phase shift of the drivers themselves...) These are not "book" crossovers at all, but rather crossovers designed from IN FRONT of the speaker, testing each element, and each change. This is 100% counter to the way systems are designed today. Today, it's all modeled on computers, then revised and optimized by computers. Then, maybe if if it's a really expensive system, some one actually sits in front of it and listens. Maybe he'll even tweak it a little. Jon Dahlquist was brilliant!

What jk determined is that from a distance of 40", and with the microphone mounted and aimed towards the middle of the top array, the drivers were all IN Phase at the crossover frequency's, and for a good range beyond with the phasing per the revised schematic.. The frequency response was also much smoother, both on and off axis.

It seemed to him, this had to be the ORIGINAL layout, unless the idea was to have a more diffuse sound-field, and the speakers were required to be listened to well off axis. We tried it that way, and it made for a much BIGGER image. However, it seems unlikely that was the intent of the ORIGINAL designer. Recall, this was touted as a PHASED ARRAY, with the drivers acoustic centers all critically aligned and focused.

We were both flabbergasted when we heard them! For me, it was a trip down memory lane, back to the early 70's. This was the sound I remembered and fell in love with. Absolute precision! I'd forgotten they could sound that good. The detailing, even in the mid range was equal to, or superior to many single panel speakers, i.e. electrostatics, ribbons, etc.

The highs are still a little harsh, a little rough, but a slight adjustment of the HI-trim pot helped a lot. It's remains a good high end, not the best, not perfect, but quite good.

Try it; don't try it....it's up to you. Maybe yours are already wired this way?

Parting shots, and a carrot -

First, and hopefully I'm not biting the hand that feeds, I am NOT a fan of a certain NY based repair center which has been around for quite some time. Despite their claims, I'm convinced they don't have a clue. For example - The "replacement DQ-10 tweeter" they charge an arm and a leg for, mounted to the cheapest thinnest piece of flakeboard I've ever seen is Wrong, wrong WRONG! It's an 8 OHM(!!!) tweeter, made by Eton (SD19) This is a fine tweeter BTW, but it will not work properly with a crossover which was designed for a 4 ohm tweeter. Even car audio people know better!
It would be much better in the DQ-20 series, having similar specs, to the scanspeak D-2008/2010's although it has a bit higher FS.
Their woofer re builds are over priced, and the're many outfits which will rebuild, re cone, re magnetise Advent 10" woofers in any case, and for a better price with equal or superior results.
Their grill cloth is questionable, too. You'd be better off with thin double knit polyester available in a variety of colors from any fabric store. It s-t-r-e-t-c-h-e-s like crazy and is all but invisible to the ear. It's also pennies on the dollar for what they charge. The stuff they sell IS NOT original, as that cloth hasn't been made it a long time. So, save some bucks.

I'm not a fan of the designer capacitor "upgrades" of the week either. Side by side, stock to re done, there is little difference, let alone improvement - but then again, it's a hobby, so enjoy it as you see fit. Just make sure you get the values right by measuring the parts yourself, AND don't swap in lower resistance inductors unless you realize that the series resistance of a choke IS part of the design of the crossover, and bass tuning.... You'll need to add resistance to keep it balanced, and then, what's the point? These coils won't saturate at the power levels that the drivers can tolerate.

The carrot - I have accumulated so much information on Dahlquist speakers, specifically the DQ-20 series, and the DQ-10's. It seems a shame to just let it go to waste, Even for those who disagree with my views, which is all they can truly be called, as I'm not the designer and can't really know; it can still be a second view, perhaps an antitheses to another thesis? Will synthesis result?

So, at some point in time I hope to post it all on the internet, along with pictures of how to put fresh surrounds on the mid range drivers with the most successful technique, testing of the crossover parts, rebuilding, replacement drivers and the mods for making them work, etc.

Just search the internet and you'll be sure to find it. Maybe 6 months, maybe a year, maybe ??? This would not be a money making venture, It would be just for fun, and a distraction from work pressures. Any/all welcome to use whatever. Assuming I ever put it together.

My apology's for the long post, but I felt this was unfinished business. Thanks to the moderators. They did the right thing in creating the group and it's been a great resource for many, even those not part of the group. I like how they stay out of it and let us shoot ourselves in the foot. With so many groups, it seems the moderators have an agenda, or at the least are on a power trip. Well done, whoever you are.. Thank you.

Best regards to all. Don't let anyone tell you Dahlquists are an old MID-FI design(I saw that on a site recently). They probably heard a poorly wired or hacked set, or they just can't hear at all.

This was quality American made gear. keep it going!

I'm sorry to see planar guy go too. Audio4antiques raises some interesting points. I am wondering if the crossover points he posts were calculated using the "nominal" impedance of each driver? As I'm sure most know, the capacitor value must be set for the actual driver impedance at the desired crossover point. I'm pretty sure Jon knew what those were.

I'm going to go back and re-verify the schematic I posted, but this emphasizes that it is necessary to state what serial number unit has been examined. Mine are early and I am sure more tweaking was done to them as production rolled on.

What is really needed is for a recapped DQ-10 to be measured using current gear to observed the overall response, including phase distribution and waterfall plots.

Something I forgot to mention. I consider the midwoofer an extension of the woofer since it only covers an octave, so ignoring the piezo you have a 3-way system with the mid-dome in a bandpass situation. That explains the apparent variations in the high/low pass for the mid-dome.

--- In Dahlquist@..., "audio4antiques" <clydeblair@> wrote:

I used the driver Re measured with Woofer Tester which is:
Woofer=3.962
Midbass=6.94
Mid Dome=3.594
Tweeter=3.539
The algorithms I used were:
Zeta 1 - L=159.155*Re/Fc, C=159155/Re*Fc
Zeta .7 - L=(159.155*Re/Fc)*.7, C=(159155/Re*Fc)*1.414
12db parallel - L=318.3*Re/Fc, C=79577/Re*Fc
There's of course a fair amount of interpolation and guess work involved in reverse engineering a design and trying to read someone else's mind, and listening tests can throw calculated values out the window.

--- In Dahlquist@..., "Abner" <fauborgflorida@> wrote:

--- In Dahlquist@..., "audio4antiques" <clydeblair@> wrote:

I'm sorry to see a contributor like planarguy leave, but he must have had a compelling reason.
First, I make no claim to be a professional crossover designer or analyst. Remembering that reverse engineering a crossover is just a crap-shoot, here's my take on the complex and mystifying DQ-10 crossover configuration. It is more than it appears. Agreed that it is ostensibly two series sections in parallel.
STAGE 1: The woofer/midwoofer (aka stage 1) has 8 ohms (R1/R1b) across the woofer Re of approx 4 ohms for an effective Re of 2.67, an apparent bass boost in response to criticism of weak bass. L2 then rolls the woofer off at 334hz. R2 added to the midwoofer Re of approx 8 ohms for an effective 12 ohms with C1 rolls it off at 165hz and should be 40uf to match up with the woofer rolloff. L1 correctly rolls the midwoofer off at approx 1503hz to the mid dome.
STAGE 2: C2 and L3 form an embedded 12db/oct parallel section. L3 correctly does its job at approx 1432hz but based on this observation C2 should be 8uf. L3 sees an Re of 3.6 ohms but C2 sees 9 ohms with R3 in series. Possibly a calculation error. For the mid dome/tweeter layout, if the intent was a quasi 12/db/.7 Zeta layout, C3 and L4 are close to being spot on. However, I don't understand redundant C6 that would also yield a 5349 hz rolloff. C4, C5 and R5 must be a tweeter smoothing circuit. Maybe scrutiny with an oscilloscope would explain it all.
Viewed as two 2-way crossovers, the woofer and mid dome in positive polarity and the mid woofer and tweeter in reverse polarity make sense. But they ARE integrated, so I think that the midwoofer should be in positive polarity and the mid dome in reverse polarity. My DQ-10s are deinstalled right now, so when I have the time I'm going to implement these changes and see what shakes out.

--- In Dahlquist@..., "planarguy" <planarguy@> wrote:

First - This will be my last post to the group. Yahoo seems determined to get in on the Facebook type market, and frankly, I'm just not sociable enough for that. I don't twitter, I don't Facebook, I don't mySpace, etc.
I've decided I don't Yahoo either. I intend to delete this Yahoo account once this is posted, so will not see any responses or questions. Sorry if that seems abrupt, but once I make a decision, it instantly gets applied. This is my attempt at a parting gift, not a slap in the face, hopefully...

The schematic -

The revised schematic came from a weekend of tests done by a very well regarded professional in the field, and he has the equipment to do it too. He is under contract so he can't publish this. He did me a favor.

You'll note that this is similar to other versions, but the driver phasing is critical, and all of the versions we've seen seem to have been redrawn, redrawn, and redrawn, with errors at each revision..

You'll note I just re worked an earlier crossover, but removed the confusing wire colors, and put in the revised polarities. On the wire colors, well... Dahlquist had some one color scheme, others another color scheme, and some were all white wires! Get an ohm meter and trace polarities to the next component on the crossover. It's the only way to KNOW you have it per the schematic.

In brief, the DQ10 crossover is 2 series crossovers, in parallel. A third leg added for the super tweeter. The low end of each driver is electrically a second order rolloff. The high end is electrically a first order rolloff. So, it an asymmetrical crossover which is common enough.

The phasing on most symmetrical 12 db/octave, aka second order filters is usually reverse phased at the crossover points. From what I've read, it shouldn't matter whether the crossover is series or parallel. That's not necessarily true though as series first order can also be reconfigured to quasi-second order which has NO phase shift, although still doesn't attenuate very well. Then a second component could be tweaked in to help protect a delicate mid or tweeter...? I know Paul W. Klipsch did things like that!

Reversing 1 driver puts the drivers IN PHASE at the crossover points, because each section is 90 degree's shifted, so 90 degree's + 90 degree's = 180 degree's, or completely reversed. This will usually cause a null at the crossover frequency, unless the driver phasing is reversed on 1 of the drivers, usually the tweeter.

DQ-10's are not symmetrical second order, so the phase shift here is only 135 degree's(ignoring the actual phase shift of the drivers themselves...) These are not "book" crossovers at all, but rather crossovers designed from IN FRONT of the speaker, testing each element, and each change. This is 100% counter to the way systems are designed today. Today, it's all modeled on computers, then revised and optimized by computers. Then, maybe if if it's a really expensive system, some one actually sits in front of it and listens. Maybe he'll even tweak it a little. Jon Dahlquist was brilliant!

What jk determined is that from a distance of 40", and with the microphone mounted and aimed towards the middle of the top array, the drivers were all IN Phase at the crossover frequency's, and for a good range beyond with the phasing per the revised schematic.. The frequency response was also much smoother, both on and off axis.

It seemed to him, this had to be the ORIGINAL layout, unless the idea was to have a more diffuse sound-field, and the speakers were required to be listened to well off axis. We tried it that way, and it made for a much BIGGER image. However, it seems unlikely that was the intent of the ORIGINAL designer. Recall, this was touted as a PHASED ARRAY, with the drivers acoustic centers all critically aligned and focused.

We were both flabbergasted when we heard them! For me, it was a trip down memory lane, back to the early 70's. This was the sound I remembered and fell in love with. Absolute precision! I'd forgotten they could sound that good. The detailing, even in the mid range was equal to, or superior to many single panel speakers, i.e. electrostatics, ribbons, etc.

The highs are still a little harsh, a little rough, but a slight adjustment of the HI-trim pot helped a lot. It's remains a good high end, not the best, not perfect, but quite good.

Try it; don't try it....it's up to you. Maybe yours are already wired this way?

Parting shots, and a carrot -

First, and hopefully I'm not biting the hand that feeds, I am NOT a fan of a certain NY based repair center which has been around for quite some time. Despite their claims, I'm convinced they don't have a clue. For example - The "replacement DQ-10 tweeter" they charge an arm and a leg for, mounted to the cheapest thinnest piece of flakeboard I've ever seen is Wrong, wrong WRONG! It's an 8 OHM(!!!) tweeter, made by Eton (SD19) This is a fine tweeter BTW, but it will not work properly with a crossover which was designed for a 4 ohm tweeter. Even car audio people know better!
It would be much better in the DQ-20 series, having similar specs, to the scanspeak D-2008/2010's although it has a bit higher FS.
Their woofer re builds are over priced, and the're many outfits which will rebuild, re cone, re magnetise Advent 10" woofers in any case, and for a better price with equal or superior results.
Their grill cloth is questionable, too. You'd be better off with thin double knit polyester available in a variety of colors from any fabric store. It s-t-r-e-t-c-h-e-s like crazy and is all but invisible to the ear. It's also pennies on the dollar for what they charge. The stuff they sell IS NOT original, as that cloth hasn't been made it a long time. So, save some bucks.

I'm not a fan of the designer capacitor "upgrades" of the week either. Side by side, stock to re done, there is little difference, let alone improvement - but then again, it's a hobby, so enjoy it as you see fit. Just make sure you get the values right by measuring the parts yourself, AND don't swap in lower resistance inductors unless you realize that the series resistance of a choke IS part of the design of the crossover, and bass tuning.... You'll need to add resistance to keep it balanced, and then, what's the point? These coils won't saturate at the power levels that the drivers can tolerate.

The carrot - I have accumulated so much information on Dahlquist speakers, specifically the DQ-20 series, and the DQ-10's. It seems a shame to just let it go to waste, Even for those who disagree with my views, which is all they can truly be called, as I'm not the designer and can't really know; it can still be a second view, perhaps an antitheses to another thesis? Will synthesis result?

So, at some point in time I hope to post it all on the internet, along with pictures of how to put fresh surrounds on the mid range drivers with the most successful technique, testing of the crossover parts, rebuilding, replacement drivers and the mods for making them work, etc.

Just search the internet and you'll be sure to find it. Maybe 6 months, maybe a year, maybe ??? This would not be a money making venture, It would be just for fun, and a distraction from work pressures. Any/all welcome to use whatever. Assuming I ever put it together.

My apology's for the long post, but I felt this was unfinished business. Thanks to the moderators. They did the right thing in creating the group and it's been a great resource for many, even those not part of the group. I like how they stay out of it and let us shoot ourselves in the foot. With so many groups, it seems the moderators have an agenda, or at the least are on a power trip. Well done, whoever you are.. Thank you.

Best regards to all. Don't let anyone tell you Dahlquists are an old MID-FI design(I saw that on a site recently). They probably heard a poorly wired or hacked set, or they just can't hear at all.

This was quality American made gear. keep it going!

I'm sorry to see planar guy go too. Audio4antiques raises some interesting points. I am wondering if the crossover points he posts were calculated using the "nominal" impedance of each driver? As I'm sure most know, the capacitor value must be set for the actual driver impedance at the desired crossover point. I'm pretty sure Jon knew what those were.

I'm going to go back and re-verify the schematic I posted, but this emphasizes that it is necessary to state what serial number unit has been examined. Mine are early and I am sure more tweaking was done to them as production rolled on.

What is really needed is for a recapped DQ-10 to be measured using current gear to observed the overall response, including phase distribution and waterfall plots.

Good stuff here. Now if we can figure out why Jon used that network with a piezo. A cap in series with a piezo will attenuate linearly, a series resistor introduces a roll-off.

Not to mention the DCR of that RF-type coil....ah sweet mystery of life

--- In Dahlquist@..., "audio4antiques" <clydeblair@> wrote:

Something I forgot to mention. I consider the midwoofer an extension of the woofer since it only covers an octave, so ignoring the piezo you have a 3-way system with the mid-dome in a bandpass situation. That explains the apparent variations in the high/low pass for the mid-dome.

--- In Dahlquist@..., "audio4antiques" <clydeblair@> wrote:

I used the driver Re measured with Woofer Tester which is:
Woofer=3.962
Midbass=6.94
Mid Dome=3.594
Tweeter=3.539
The algorithms I used were:
Zeta 1 - L=159.155*Re/Fc, C=159155/Re*Fc
Zeta .7 - L=(159.155*Re/Fc)*.7, C=(159155/Re*Fc)*1.414
12db parallel - L=318.3*Re/Fc, C=79577/Re*Fc
There's of course a fair amount of interpolation and guess work involved in reverse engineering a design and trying to read someone else's mind, and listening tests can throw calculated values out the window.

--- In Dahlquist@..., "Abner" <fauborgflorida@> wrote:

--- In Dahlquist@..., "audio4antiques" <clydeblair@> wrote:

I'm sorry to see a contributor like planarguy leave, but he must have had a compelling reason.
First, I make no claim to be a professional crossover designer or analyst. Remembering that reverse engineering a crossover is just a crap-shoot, here's my take on the complex and mystifying DQ-10 crossover configuration. It is more than it appears. Agreed that it is ostensibly two series sections in parallel.
STAGE 1: The woofer/midwoofer (aka stage 1) has 8 ohms (R1/R1b) across the woofer Re of approx 4 ohms for an effective Re of 2.67, an apparent bass boost in response to criticism of weak bass. L2 then rolls the woofer off at 334hz. R2 added to the midwoofer Re of approx 8 ohms for an effective 12 ohms with C1 rolls it off at 165hz and should be 40uf to match up with the woofer rolloff. L1 correctly rolls the midwoofer off at approx 1503hz to the mid dome.
STAGE 2: C2 and L3 form an embedded 12db/oct parallel section. L3 correctly does its job at approx 1432hz but based on this observation C2 should be 8uf. L3 sees an Re of 3.6 ohms but C2 sees 9 ohms with R3 in series. Possibly a calculation error. For the mid dome/tweeter layout, if the intent was a quasi 12/db/.7 Zeta layout, C3 and L4 are close to being spot on. However, I don't understand redundant C6 that would also yield a 5349 hz rolloff. C4, C5 and R5 must be a tweeter smoothing circuit. Maybe scrutiny with an oscilloscope would explain it all.
Viewed as two 2-way crossovers, the woofer and mid dome in positive polarity and the mid woofer and tweeter in reverse polarity make sense. But they ARE integrated, so I think that the midwoofer should be in positive polarity and the mid dome in reverse polarity. My DQ-10s are deinstalled right now, so when I have the time I'm going to implement these changes and see what shakes out.

--- In Dahlquist@..., "planarguy" <planarguy@> wrote:

First - This will be my last post to the group. Yahoo seems determined to get in on the Facebook type market, and frankly, I'm just not sociable enough for that. I don't twitter, I don't Facebook, I don't mySpace, etc.
I've decided I don't Yahoo either. I intend to delete this Yahoo account once this is posted, so will not see any responses or questions. Sorry if that seems abrupt, but once I make a decision, it instantly gets applied. This is my attempt at a parting gift, not a slap in the face, hopefully...

The schematic -

The revised schematic came from a weekend of tests done by a very well regarded professional in the field, and he has the equipment to do it too. He is under contract so he can't publish this. He did me a favor.

You'll note that this is similar to other versions, but the driver phasing is critical, and all of the versions we've seen seem to have been redrawn, redrawn, and redrawn, with errors at each revision..

You'll note I just re worked an earlier crossover, but removed the confusing wire colors, and put in the revised polarities. On the wire colors, well... Dahlquist had some one color scheme, others another color scheme, and some were all white wires! Get an ohm meter and trace polarities to the next component on the crossover. It's the only way to KNOW you have it per the schematic.

In brief, the DQ10 crossover is 2 series crossovers, in parallel. A third leg added for the super tweeter. The low end of each driver is electrically a second order rolloff. The high end is electrically a first order rolloff. So, it an asymmetrical crossover which is common enough.

The phasing on most symmetrical 12 db/octave, aka second order filters is usually reverse phased at the crossover points. From what I've read, it shouldn't matter whether the crossover is series or parallel. That's not necessarily true though as series first order can also be reconfigured to quasi-second order which has NO phase shift, although still doesn't attenuate very well. Then a second component could be tweaked in to help protect a delicate mid or tweeter...? I know Paul W. Klipsch did things like that!

Reversing 1 driver puts the drivers IN PHASE at the crossover points, because each section is 90 degree's shifted, so 90 degree's + 90 degree's = 180 degree's, or completely reversed. This will usually cause a null at the crossover frequency, unless the driver phasing is reversed on 1 of the drivers, usually the tweeter.

DQ-10's are not symmetrical second order, so the phase shift here is only 135 degree's(ignoring the actual phase shift of the drivers themselves...) These are not "book" crossovers at all, but rather crossovers designed from IN FRONT of the speaker, testing each element, and each change. This is 100% counter to the way systems are designed today. Today, it's all modeled on computers, then revised and optimized by computers. Then, maybe if if it's a really expensive system, some one actually sits in front of it and listens. Maybe he'll even tweak it a little. Jon Dahlquist was brilliant!

What jk determined is that from a distance of 40", and with the microphone mounted and aimed towards the middle of the top array, the drivers were all IN Phase at the crossover frequency's, and for a good range beyond with the phasing per the revised schematic.. The frequency response was also much smoother, both on and off axis.

It seemed to him, this had to be the ORIGINAL layout, unless the idea was to have a more diffuse sound-field, and the speakers were required to be listened to well off axis. We tried it that way, and it made for a much BIGGER image. However, it seems unlikely that was the intent of the ORIGINAL designer. Recall, this was touted as a PHASED ARRAY, with the drivers acoustic centers all critically aligned and focused.

We were both flabbergasted when we heard them! For me, it was a trip down memory lane, back to the early 70's. This was the sound I remembered and fell in love with. Absolute precision! I'd forgotten they could sound that good. The detailing, even in the mid range was equal to, or superior to many single panel speakers, i.e. electrostatics, ribbons, etc.

The highs are still a little harsh, a little rough, but a slight adjustment of the HI-trim pot helped a lot. It's remains a good high end, not the best, not perfect, but quite good.

Try it; don't try it....it's up to you. Maybe yours are already wired this way?

Parting shots, and a carrot -

First, and hopefully I'm not biting the hand that feeds, I am NOT a fan of a certain NY based repair center which has been around for quite some time. Despite their claims, I'm convinced they don't have a clue. For example - The "replacement DQ-10 tweeter" they charge an arm and a leg for, mounted to the cheapest thinnest piece of flakeboard I've ever seen is Wrong, wrong WRONG! It's an 8 OHM(!!!) tweeter, made by Eton (SD19) This is a fine tweeter BTW, but it will not work properly with a crossover which was designed for a 4 ohm tweeter. Even car audio people know better!
It would be much better in the DQ-20 series, having similar specs, to the scanspeak D-2008/2010's although it has a bit higher FS.
Their woofer re builds are over priced, and the're many outfits which will rebuild, re cone, re magnetise Advent 10" woofers in any case, and for a better price with equal or superior results.
Their grill cloth is questionable, too. You'd be better off with thin double knit polyester available in a variety of colors from any fabric store. It s-t-r-e-t-c-h-e-s like crazy and is all but invisible to the ear. It's also pennies on the dollar for what they charge. The stuff they sell IS NOT original, as that cloth hasn't been made it a long time. So, save some bucks.

I'm not a fan of the designer capacitor "upgrades" of the week either. Side by side, stock to re done, there is little difference, let alone improvement - but then again, it's a hobby, so enjoy it as you see fit. Just make sure you get the values right by measuring the parts yourself, AND don't swap in lower resistance inductors unless you realize that the series resistance of a choke IS part of the design of the crossover, and bass tuning.... You'll need to add resistance to keep it balanced, and then, what's the point? These coils won't saturate at the power levels that the drivers can tolerate.

The carrot - I have accumulated so much information on Dahlquist speakers, specifically the DQ-20 series, and the DQ-10's. It seems a shame to just let it go to waste, Even for those who disagree with my views, which is all they can truly be called, as I'm not the designer and can't really know; it can still be a second view, perhaps an antitheses to another thesis? Will synthesis result?

So, at some point in time I hope to post it all on the internet, along with pictures of how to put fresh surrounds on the mid range drivers with the most successful technique, testing of the crossover parts, rebuilding, replacement drivers and the mods for making them work, etc.

Just search the internet and you'll be sure to find it. Maybe 6 months, maybe a year, maybe ??? This would not be a money making venture, It would be just for fun, and a distraction from work pressures. Any/all welcome to use whatever. Assuming I ever put it together.

My apology's for the long post, but I felt this was unfinished business. Thanks to the moderators. They did the right thing in creating the group and it's been a great resource for many, even those not part of the group. I like how they stay out of it and let us shoot ourselves in the foot. With so many groups, it seems the moderators have an agenda, or at the least are on a power trip. Well done, whoever you are.. Thank you.

Best regards to all. Don't let anyone tell you Dahlquists are an old MID-FI design(I saw that on a site recently). They probably heard a poorly wired or hacked set, or they just can't hear at all.

This was quality American made gear. keep it going!

I'm sorry to see planar guy go too. Audio4antiques raises some interesting points. I am wondering if the crossover points he posts were calculated using the "nominal" impedance of each driver? As I'm sure most know, the capacitor value must be set for the actual driver impedance at the desired crossover point. I'm pretty sure Jon knew what those were.

I'm going to go back and re-verify the schematic I posted, but this emphasizes that it is necessary to state what serial number unit has been examined. Mine are early and I am sure more tweaking was done to them as production rolled on.

What is really needed is for a recapped DQ-10 to be measured using current gear to observed the overall response, including phase distribution and waterfall plots.

First - This will be my last post to the group. Yahoo seems determined to get in on the Facebook type market, and frankly, I'm just not sociable enough for that. I don't twitter, I don't Facebook, I don't mySpace, etc.
I've decided I don't Yahoo either. I intend to delete this Yahoo account once this is posted, so will not see any responses or questions. Sorry if that seems abrupt, but once I make a decision, it instantly gets applied. This is my attempt at a parting gift, not a slap in the face, hopefully...

The schematic -

The revised schematic came from a weekend of tests done by a very well regarded professional in the field, and he has the equipment to do it too. He is under contract so he can't publish this. He did me a favor.

You'll note that this is similar to other versions, but the driver phasing is critical, and all of the versions we've seen seem to have been redrawn, redrawn, and redrawn, with errors at each revision..

You'll note I just re worked an earlier crossover, but removed the confusing wire colors, and put in the revised polarities. On the wire colors, well... Dahlquist had some one color scheme, others another color scheme, and some were all white wires! Get an ohm meter and trace polarities to the next component on the crossover. It's the only way to KNOW you have it per the schematic.

In brief, the DQ10 crossover is 2 series crossovers, in parallel. A third leg added for the super tweeter. The low end of each driver is electrically a second order rolloff. The high end is electrically a first order rolloff. So, it an asymmetrical crossover which is common enough.

The phasing on most symmetrical 12 db/octave, aka second order filters is usually reverse phased at the crossover points. From what I've read, it shouldn't matter whether the crossover is series or parallel. That's not necessarily true though as series first order can also be reconfigured to quasi-second order which has NO phase shift, although still doesn't attenuate very well. Then a second component could be tweaked in to help protect a delicate mid or tweeter...? I know Paul W. Klipsch did things like that!

Reversing 1 driver puts the drivers IN PHASE at the crossover points, because each section is 90 degree's shifted, so 90 degree's + 90 degree's = 180 degree's, or completely reversed. This will usually cause a null at the crossover frequency, unless the driver phasing is reversed on 1 of the drivers, usually the tweeter.

DQ-10's are not symmetrical second order, so the phase shift here is only 135 degree's(ignoring the actual phase shift of the drivers themselves...) These are not "book" crossovers at all, but rather crossovers designed from IN FRONT of the speaker, testing each element, and each change. This is 100% counter to the way systems are designed today. Today, it's all modeled on computers, then revised and optimized by computers. Then, maybe if if it's a really expensive system, some one actually sits in front of it and listens. Maybe he'll even tweak it a little. Jon Dahlquist was brilliant!

What jk determined is that from a distance of 40", and with the microphone mounted and aimed towards the middle of the top array, the drivers were all IN Phase at the crossover frequency's, and for a good range beyond with the phasing per the revised schematic.. The frequency response was also much smoother, both on and off axis.

It seemed to him, this had to be the ORIGINAL layout, unless the idea was to have a more diffuse sound-field, and the speakers were required to be listened to well off axis. We tried it that way, and it made for a much BIGGER image. However, it seems unlikely that was the intent of the ORIGINAL designer. Recall, this was touted as a PHASED ARRAY, with the drivers acoustic centers all critically aligned and focused.

We were both flabbergasted when we heard them! For me, it was a trip down memory lane, back to the early 70's. This was the sound I remembered and fell in love with. Absolute precision! I'd forgotten they could sound that good. The detailing, even in the mid range was equal to, or superior to many single panel speakers, i.e. electrostatics, ribbons, etc.

The highs are still a little harsh, a little rough, but a slight adjustment of the HI-trim pot helped a lot. It's remains a good high end, not the best, not perfect, but quite good.

Try it; don't try it....it's up to you. Maybe yours are already wired this way?

Parting shots, and a carrot -

First, and hopefully I'm not biting the hand that feeds, I am NOT a fan of a certain NY based repair center which has been around for quite some time. Despite their claims, I'm convinced they don't have a clue. For example - The "replacement DQ-10 tweeter" they charge an arm and a leg for, mounted to the cheapest thinnest piece of flakeboard I've ever seen is Wrong, wrong WRONG! It's an 8 OHM(!!!) tweeter, made by Eton (SD19) This is a fine tweeter BTW, but it will not work properly with a crossover which was designed for a 4 ohm tweeter. Even car audio people know better!
It would be much better in the DQ-20 series, having similar specs, to the scanspeak D-2008/2010's although it has a bit higher FS.
Their woofer re builds are over priced, and the're many outfits which will rebuild, re cone, re magnetise Advent 10" woofers in any case, and for a better price with equal or superior results.
Their grill cloth is questionable, too. You'd be better off with thin double knit polyester available in a variety of colors from any fabric store. It s-t-r-e-t-c-h-e-s like crazy and is all but invisible to the ear. It's also pennies on the dollar for what they charge. The stuff they sell IS NOT original, as that cloth hasn't been made it a long time. So, save some bucks.

I'm not a fan of the designer capacitor "upgrades" of the week either. Side by side, stock to re done, there is little difference, let alone improvement - but then again, it's a hobby, so enjoy it as you see fit. Just make sure you get the values right by measuring the parts yourself, AND don't swap in lower resistance inductors unless you realize that the series resistance of a choke IS part of the design of the crossover, and bass tuning.... You'll need to add resistance to keep it balanced, and then, what's the point? These coils won't saturate at the power levels that the drivers can tolerate.

The carrot - I have accumulated so much information on Dahlquist speakers, specifically the DQ-20 series, and the DQ-10's. It seems a shame to just let it go to waste, Even for those who disagree with my views, which is all they can truly be called, as I'm not the designer and can't really know; it can still be a second view, perhaps an antitheses to another thesis? Will synthesis result?

So, at some point in time I hope to post it all on the internet, along with pictures of how to put fresh surrounds on the mid range drivers with the most successful technique, testing of the crossover parts, rebuilding, replacement drivers and the mods for making them work, etc.

Just search the internet and you'll be sure to find it. Maybe 6 months, maybe a year, maybe ??? This would not be a money making venture, It would be just for fun, and a distraction from work pressures. Any/all welcome to use whatever. Assuming I ever put it together.

My apology's for the long post, but I felt this was unfinished business. Thanks to the moderators. They did the right thing in creating the group and it's been a great resource for many, even those not part of the group. I like how they stay out of it and let us shoot ourselves in the foot. With so many groups, it seems the moderators have an agenda, or at the least are on a power trip. Well done, whoever you are.. Thank you.

Best regards to all. Don't let anyone tell you Dahlquists are an old MID-FI design(I saw that on a site recently). They probably heard a poorly wired or hacked set, or they just can't hear at all.

This was quality American made gear. keep it going!