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Hi there,

I inherited a pair of Dahlquist DQ-10 and have been working on restoring them.? I had the amplifier professionally serviced, but I am working on the speakers myself.?

Last night I refoamed the woofers.? I was excited to reassemble everything and test it this morning, but it sounded horrible!? I assumed maybe it was due to the old 80 uF capacitor, so I replaced those with a much nicer pair, but the sound didn't change at all.? The high frequency content sounds normal, but when the bass drops it sounds like someone blowing raspberries.

I'm going to replace all the capacitors in the crossover tonight, but I wanted to check here to see whether anyone had other suggestions first.? The other capacitors are the yellow type that everyone said should still be good, so I'm confused why it still sounds like garbage.??

Do you think replacing all of the capacitors will fix the sound?? I can't think of anything else that I changed; the distortion isn't limited to the woofer that I refoamed, but if there is an obvious mistake to check (like if I inverted the polarity by mistake) then please let me know.? I checked the fuses and both are fine, although one was a 20A fuse so I think I need to replace it with a 2-3A fuse like it says.??

One thing - in one of the rebuild member guides, it mentions putting rope caulk behind the woofer when screwing it back into the main body.? I didn't notice any caulk when I took it out and didn't think to add any when I put it back in.? I doubt this is what is causing the issue, but I'm curious whether anyone thinks that is a big deal.? What would not including it do to the sound?

And as for the wires, I thought I wired it the way it was originally (colored wire to + terminal, white wire to - terminal of speaker), but I'm not 100% positive.? Again, I don't think that explains it sounding like blowing raspberries, but I want to resolve all potential issues if I can.

I don’t know what blowing raspberries sound like other than a fart like sound . Never heard a speaker do that.
Can you send an audio clip?
Lacking that I would focus on the woofers, particularly the refoamed one.
With the amp turned off gently push the woofer EVENLY in near the intersection of the voicecoil and cone until the suspension bottoms. Listen for scraping sounds. Then?rapidly remove your hand. The cone should take at least a few seconds to return to its resting position.
if it returns rapidly you have a leak, probably because the woofer is not sealed to the enclosure. It is very important that this is sealed tightly. Know that since you have the grill removed air is likely to leak out of the holes the screws make for attachment. You can temporally tape over those holes to eliminate that leak. Leaks can be hard to localize. You can use a mechanics stethoscope ?or something similar to find the leaks by listening for a air rushing sound.

f you hear rubbing when you push the cone in you will probably have to repeat the refoaming exercise paying very careful attention to voice-coil centering.

Of course getting all the polarities exactly, correct is a critical issue. However, that will not cause the issue described. likewise, bad capacitor’s will not cause issues you describe.

Thank you for taking the time to respond.? Sadly, I did mean that the speakers make fart noises, and I'm even more ashamed to say it had nothing to do with the speakers.

I was using a hand-me-down receiver as a pre-amp to the power amplifier, and I didn't test it with other speakers first.? No idea why it caused that level of distortion, but I bypassed the receiver and everything worked perfectly, so I figured out it was one particular input on the receiver is totally messed up.? I switched to a different input and that works and now the speakers sound amazing.