开云体育

hi all - i've noticed a number of "homemade hydrophone" plans online - and i've seen a whole host of commercial hydrophone products out there. i'm curious if anyone can speak about the differences between a "five dollar DIY" plasti-dipped contact mic and a $5,0000 science grade nautical device? thanks, cx

A few years back I bought some EM172s to use with my Zoom H5. More recently I've been lucky enough to pick up a lightly used MixPre6ii. I've been using the 172s with no problems, but thought I would go back and check the R value to make sure it was optimised for the MP. I soldered an XLR to some header pins to make it easier to test things on a breadboard and was alarmed at the results. Wiring is as follows: Pin1 - resistor Pin 2 - capacitor +ve Pin three to what would be the +ve terminal on the mic The -ve cap lead goes to the other resistor terminal. I played with values of R until going all the way to 1MOhm which gives a reading of 7-8v which fluctuates a lot. As a side note with the negative lead of the cap connected to pin 2 V was ~34v so I sawpped it to be positive to pin 2 This doesn't seem to be even remotely close to the previous results in the PDF that Richard Lee created. Am I missing something?

Hi MicBuilders! I'm new to this group. Many greetings and hello to everybody! I would like to give it a try to build a special 'Sound Sleuth Bamboo' version. The aim is to achieve the most natural-sounding recording possible in combination with natural and sustainable materials. Like bamboo! :-) I'm wondering if anyone could give any advice regarding the optimal selection of electronic components. Is the article at Instructables still the way to go? Or are there any improvements or changes I should know about before I start ordering parts? I really love to work with bamboo from time to time but I'm not so familiar with electronic circuit board design. Sound Sleuth looks so simple. Is it really that simple? How is the recording quality? To give you an idea of what the sleuth bamboo version may (or better not) look like, I would like to send you some pictures of a prototype bamboo mic holder that I built two years ago and that has served me well. The holder can be attached to a long bamboo pole if necessary, to record closer to the tree top. The orange strap is a replacement strap for an 8mm film projector. which was not expensive and works just fine. The microphone is a Sony ECM-678 that I found in a junk corner of a reuse store with a 'No tone' sticker on it. It works well again. My image of the mic housing for nature recordings is a kind of bamboo blip(upright), which can be attached to bamboo poles to record more close to the roof top without disturbing the environment too much. Perhaps leaning against a tree and fastened. Available recording devices: Sony PCM-M10 or USB powered audio interface with phantom power. If you are interested in listening to sounds I recorded, you can find some on the YT-channel I recently started at: https://www.youtube.com/@NaturePattern (created for fun...no monetizing...no commercials...). In case you have any questions, don't hesitate to drop me a note. Or if you need any information about bamboo. As for the design of the bamboo housed microphone circuit board, it would be great if someone could point me in the right direction. Many thanks! Heinz (amateur photographer, field recordist, hobbyist, former SysEng...respecting the diversity of nature...)

I happened upon Boya 35C-XLR, 3,5 mm jack to XLR adapters and they are inexpensive (around 10 USD), full metal (aluminium) and well made. There are two versions: one, shorter - 58 mm, just plain 3,5 mm socket wired straight to XLR plug and, longer ("PRO") - 68 mm, with a PCB inside providing 48V to the 3,5 mm socket. They make for a really great mic body. Being metal nicely shield the capsule and are really sturdy. I mounted AOMs 5024 in them, powered by SimpleP48 and they work great. The thing is they're bear to disassemble. Therefore one need to have basic tools and some technical dexterity. One - the aluminium fine threads have nasty tendency to lock up. Two - there is a bit of thread glue used.. I had to make jigs/holders to squeeze both halves really strong to unscrew the body. Simple but necessary. Made from scraps of MDF I had laying around, the cutouts (22 mm hole saw) covered in thin layer of silicone. One jig is clamped in the vice, the other by carpenter's clamp. A sharp hammer tap on the clamp breaks the bond and the halves can be unscrewed. (I scratched the first adapter with hand grips even through some leather and rubber band). For the 3,5 mm socket I use a remover for broken bolts. Sure, it ruins the socket but I do not need it. Otherwise its thin edge is almost impossible to grip. Then the hole left by the socket must be drilled out to 10,5 mm. No deeper than 5,5-6 mm! AOM capsule in thick heat shrink plus a bit (~1/4 turn) of electrical tape fits nicely and securely. From then on everything else is straightforward - unsolder all original wires, solder together all of the numerous components of the SimpleP48, remember to thread wires from the capsule through the plastic collar needed to hold XLR plug in place, forget about it, desolder wires, thread through the collar cursing one's own stupidity, solder to the XLR plug, twist the top (with the capsule) counter-clockwise several turns before screwing both halves together. It takes good several turns to screw it all together - you do not want to rear out the wires. Done! If you do not mind the BOYA logo on the side and do not want to hunt for LOMs - they're pretty nifty mics.

Hello everyone, I was thinking how cool it would be to record a thunderstorm with a pair of earthworks M50 measurement mics seeing as their frequency response goes way down into subsonic territory. Then I looked at the price tag. Yeah I won't be taking a pair of those things out into the rain any time soon. Does anyone know what top secret Roswell technology Earthworks is using here? Do they manufacture their own capsules or is there an omni capsule out there that is equivalent? I've also thought about the old speaker-wired-as-a-microphone, sub kick idea, but I don't have any way to measure the frequency response of a speaker/microphone. At least not in any practicable way.

Hi, I've been a long -time lurker. I thought I would post up something I'm working on. I've been interested in getting a small, inexpensive Blumlein pair together for recording piano and thought I would try and see if the SimpleP48 works with two electret capsules, out of phase, on one xlr, with two sets of symmetrical capacitors and resistors. It works! I'm using PUI AUM-4537L-HD-R cardioids with 4.7uF caps and 87KOhms resistors. I'm going to try it out with PUI AUM 5241L next, which should be more suitable in terms of coping with the signal from a piano. Richard

I think the name Alice (in microphones) was created by Scott Helmke. If I remember correctly, it was based on 16mm capsule and a FET circuit. Now I see "Alice" all over in the mic DIY communities. Homero Leal calls his "Pimped Alice". Jules Ryckebusch calls his "OPA based Alice". What defines a microphone an Alice?

Hello all, I suspect that the topic of choosing the right resistor values for biasing FETs might be done to death by people as inexperienced as me, but I've searched through the messages and haven't really found anything that answers my questions. I'm trying to make some little cardioid lavaliers using AUM-5241L-HD capsules, which should be appropriate for the simple p48 circuit having an internal FET. I understand that I have to wire the sourse and ground terminals together, but I can't for the life of me figure out the calculations for the resistor values chosen in these circuits. I can use ohm's law to figure out how to bring the voltage from the power supply into the acceptable range, but when I look at the suggested resistor values for circuits for other capsules that's not what the resistor is doing. The typical application circuit on the datasheet (below) shows the same two component setup but with a 3V supply voltage, using a 3.3k resistor. Could I just insert a resistor on the drain to bring the supply voltage down to 3V and leave the rest of the circuit the same? If not, could I replace the biasing resistor with one that can bring the voltage into an acceptable range in series with a pot and find the appropriate value by tinkering? I apologise if I'm way off base, my electronics knowledge is still very limited. Thank you all!

Ricardo addresses this in his /g/MicBuilders/files/Ricardo/SimpleP48/simpleP48.pdf Basically you want the resistor to give between 5 V – 10 V across the capsule. But check that the voltage is not too high for the Vds limit of the FET in the capsule; some, like the NEC 2sk4027 FET used in some Primo capsules do not like that.

Hello all, I thought I'd share my diy wind screens. They cost probably less than 50c each to make, are suitable for beginners to felting and do a fantastic job. For the basic shape I wet felted them - basically wetting the wool with very soapy water, shaping them around the mold (a housing for a sound sleuther mic i made covered in in foil), and agitating it until it roughly felted together. Let dry, rinse soap off and let dry again. Then I took it off the mold, used a felting needle to tidy it up and fill in the thinner patches. For the dead cat style screens I loosely felted long pieces of felting wool in piece by piece until it looked like a troll doll. Overall less than two hours work each. They don't shed much at all either. If you are frugal and hate plastics like me it's a very feasible option.

I’m new to the group and impressed by the knowledge and experience here in the group! I have some questions about Primo EM23: I asked Primo about phantom 48V, and got two ‘answers’: and which of the two suggested circuits is preferred? i.e. one or two capacitors? Then about the FET 2SK118 O1 - this one is no longer available, and the replacement, suggested by Primo, is only sold in quantities of 2,500 from Mouser: any suggestions of alternative FET or where the 2N5457 can be bought by piece? In general, should the electronics be close to the mic capsule or close to the recorder, i.e. inside the XLR, when (5 to) 10 meters in between? I do mainly nature sound recordings … Cheers! /G?ran G?ran Birgersson G?teborg, Sweden