Hand-built microphone pickup/preamp system: Revolutionary DIY project
 

Hi All,

Just wanted to share my project with those who never been happy with the most of acoustic pickup systems, or wished to find alternatives to expensive internal condenser microphones.

This thread is about the pickup-element built out of little dynamic capsules taken from some high-quality earphones/earplugs/earbuds .... As you may expect, higher coil resistance capsules do perform the best, the higher coil resistance is, the better. There are some earphone capsules with over 600 Ohm coils on the market, but I do use the ones with 140-160 Ohm coil resistance and they do the tasks just phenomenally.

With some dedication and accuracy you are on the right way to equip your acoustics with the unique pickup-element capturing both the sound waves as well as vibrations.

Very briefly, in the form of a listing, on how it is made and what are the basic rules and steps to follow and get the one built successfully:

1. Higher coil resistance capsules are the must;
2. Metal-housing capsules are the must;
3. There should necessarily be used buffer in-between the guitar’s top and capsule, so the capsule must be built-in into housing made out of real bone or bone-like material and under some pressure to ensure full vibration capture and transfer;
4. You should avoid attaching the capsule directly to the guitar's top, this way you get too much Lows;
5. The capsule housing (shown on the image below!) has a specifically designed 2-stage top’s surface, the first (highest) provides a direct connection to the guitar’s top while the second, the lower, is used for gluing;
6. The glue: you should use resin glue which, when dried, offers sufficient pickup-to-soundboard tension for the most of sound and vibration transfer;
7. You can even use two identical dynamic capsules (perhaps, more but I got tested two!) wired in-series for doubling the capsule’s output which typically under 1mV;
8. You will have to build specific preamplifier with low impedance input and sensitivity of <1mV;
9. Due to low impedance, you can install this pickup on your instrument passively and use external preamplifier;
10. Even laminate guitars may sound super with these little dynamic capsules…..

This dynamic pickup will make you forget about any other pickup types and models, it is a real pickup-killer….. wishing you patience and luck!

http://forum.vegalab.ru/attachment.p...3&d=1528973729 http://forum.vegalab.ru/attachment.p...5&d=1528973915 http://forum.vegalab.ru/attachment.p...2&d=1528973587

http://forum.vegalab.ru/attachment.p...9&d=1542831185

Interesting. Do you happen to have a sound sample of this pickup idea?

Hi, no actually, I do not have either time, aim or a specific gear for doing recordings, even the samples..... experimenting and testing over the years, I would have to had someone recommending this method and technique for achieving a real studio sound, sadly I found nothing similar .... building this system would cost almost nothing, however it definitely requires accuracy ...... if you do not know when and where to start, just listen to the best-ever piezo-pickup, so you will get ready to go over such dynamic system.....

Miniature dynamic & condenser microphone pickup system
 

Greetings!

This project was finished few weeks ago, so I wanted to share the result and the idea of building such a pickup system and ending with all your search for a 'true' acoustic pickup, wasting time and money......

With some dedication and accuracy you are on the right way to equip your acoustics with the unique pickup-element capturing both the sound waves as well as sound-board vibrations. This pickup will make you forget about any other expensive or inexpensive manufactured piezo/magnetic/microphone pickup types and models, it is a real pickup-killer….. wishing you patience and luck!

Very briefly, in the form of a listing, on how it is made and what are the basic rules and steps to follow and get the one built successfully:

1. Higher coil resistance capsules are the must;
2. Metal-housing capsules are the must;
3. There should necessarily be used buffer in-between the guitar’s top and capsule, so the capsule must be built-in into housing made out of real bone or bone-like material and under some pressure to ensure full vibration capture and transfer;
4. The built-in capsules must have an internal venting into the bone-housing (see the image!);
5. The capsule housing (shown on the image below!) has a specifically designed 2-stage top’s surface, the first (highest) provides a direct connection to the guitar’s top while the second, the lower, is used for gluing;
6. The glue: you should use resin glue which, when dried, offers sufficient pickup-to-soundboard tension for the most of sound and vibration transfer;
7. You can even use two identical dynamic capsules (perhaps, more but I got tested two!) wired in-series for doubling the capsule’s output which typically is under 1mV;
8. You will have to build specific preamplifier with low impedance input and sensitivity of <1mV;
9. Miniature *Oktava MKE-3 microphone is internally mounted with Velcro tape on to the back of the guitar;
10. ECM microphone is easily phantom-powered from the preamp through the standard guitar stereo cable by 3-9 V;
11. Due to low impedance, this pickup-system is passively installed, no batteries in the guitar's body;
12. Even laminate guitars may sound good with these little dynamic/condenser mic capsules…..


*Miniature Oktava MKE-3 microphone: this old Oktava ECM microphone can not be beat, I have tested dozens of high quality modern mic capsules except only Primo and Puiaudio, I can not say anything on Primo or Puiaudio mic capsules, but nothing comes any close to the voice and brilliance of MKE-3, it sounds in the guitar's body as if it were externally professionally positioned in the studio environment...... and MKE-3 is super-affordable !!


Below are the specifications and schematic of Mr. Acoustic external 2-channel preamp unit for steel-string acoustic guitar .....

Gain=100
THD=0.002%
Noise=36µV



And some of the actual images......

It seems your images aren't working. Could you provide some sound examples of this? Also, how does it handle on stage? Is it feedback prone?

I am sorry for the images, however my PC displays the photos properly.

Feedback is just a part of amplification, do not ever trust false and anti-scientific adverts...... you should use sound-hole feedback silicone cover, it does all you need!!

Yes please post some sound samples!

I have not ever recorded on my laptop, I do not have any special quality devices to get the professional audio.....

Do you think I can do that by directly switching the preamp into the PC audio input ???

Assuming you're on a desktop PC with a motherboard that has an integrated sound card, there is a chance you'll have a line in-port you could use with your preamp.

Your preamp doesn't seem to have a headphone input, so you'll probably have to tinker with some digital monitoring of the pickup signal. If you're completely inexperienced in recording, for this situation I suggest just downloading the free DAW, Audacity. There you can easily record some raw footage of your pickup.

Wow. Very creative! I had a similar idea of using DML speakers as a pickup. It worked well on my hammered dulcimer. DML speakers can be quite inexpensive and the sound quality is quite good (atleast it was on my dulcimer).

Super cool, thanks for this. Would love to hear how it sounds! Maybe Ill contribute something too by posting some of my dml speaker recordings. Maybe Ill have some time this weekend.

Sure, the laptop has a sound-card, and it should have stereo line input .....
Will try to organize it all as soon as I get some free time and enthusiasm.... :-)

In general, no one would believe that studios are recording music through any piezo or magnetic pickup elements, moreover there are very few microphones traditionally used in studios due to their outstanding characteristics .....

.... This is a very basic approach to amplify an acoustic instrument with microphones, with miniature mics in the body...... I do not believe in any piezo/magnetic pickups, these are just a compromise manufactured and installed easily in mass-production, so we should leave this for those who enjoys piezo and/or el-magnetic sound............

In this particular pickup-system we have three type mic sounds - condenser, dynamic (moving-coil) and vibration through dynamic mic capsule !!!

This is also the way to make an economy by purchasing quality solid-wood guitar rather than lower quality electric-acoustic, for the most guitar fans this should be just an ideal solution !!

NOTE: selecting high-impedance 150-600 Ohm dynamic (moving-coil) capsule requires checking them all, modern miniature ear-phone dynamic capsules are NOT ALL built with a "microphone technology" using copper-coil and diaphragm, there are many others with different diaphragm materials as plenty of standard mass-production loud-speakers using silicone, aluminium and other materials for the CONE........ I have another 150 Ohm Samsung capsule which uses such a cone material and it is unusable for such a project......

Good luck!

Isn't this a re-hash of Shertler's (the actual company) instrument pickup, which houses the same type of element within the housing, adding mass to the voice-coil assembly to create electrical energy from movement of the housing as the mass attempts to hold the coil in a stationary position?

This sounds like a great opportunity to get a cease and desist letter!

No, my forum-name Schertler is absolutely randomly selected and I am not a Company staff...... however, dynamic microphones and moving-coil transducers are the two different terms of the one particular category..... my story with little dynamic capsules has begun accidentally by discovering at home the one with 150 Ohm coil-impedance, then a quick-check-test......
Dynamic microphones and loudspeakers are both the same technology, so the ear-plug dynamic capsule built as a miniature loudspeaker can be used as a mic too, but it must be first tested for a real output and frequency range.....

Have you ever seen how the Schertler DYN-G looks internally ?

No matter how the system of magnet, membrane and coil is assembled, it all is called the electromagnetic induction and would work anyway but the quality will depend on to the used materials and similarities with the actual dynamic microphone.

The frequency range of this little dynamic capsule was my initial concern, however, the result truly is phenomenal, firmly attached to the guitar's top and/or bridge-plate it has almost the same Highs as the condenser Oktava microphone !!!

I have never seen anyone having installed such a mics' combination into one acoustics, and one might note that using one ECM mic in the guitar is absolutely enough for a live use, I agree, my idea was not about mounting two mics in one guitar but about using miniature dynamic ear-phone capsule as an alternative mic-pickup to grotty piezo sound and/or magnetic pickup...... however, due to a tiny sizes and easy installation I got them both mounted in my new instrument, in finally, and got different microphone voices that is very pleasant.....

Thanks for reading!

Not implying that you are related to Shertler of the transducer company liniage, just that the idea is similar.

I did try using a small miniature speaker as a soundboard transducer many years ago. I glued a small weight over the voice coil attachment so the cone would resist movement as the body of the speaker reacted to soundboard vibration. It worked, but I found other methods of using piezo materials resulted in a higher output level with better response than the "reverse microphone" that I created.

Your mic elements sound like they work better than what I achieved.

There is a manufacturer who markets a surface mount motion sensor that is also used as a soundboard transducer. The new Fender Acoustisonic uses this PC board component as an input to it's trigger for the built-in sound modeling in the guitar,

I am not sure that disassembling the metal-housing of these dynamic capsules and modifying its tiny internal parts is possible without damaging it, moreover, these metal-housings are sealed that makes their disassembling just a wrong way in achieving any result, even theoretical ......
Piezos: sorry, I would not consider this type or method of amplifying steel-string acoustics, however, piezos are OK with double bass (contrabass), ukulele....

This method of using such little dynamic capsules work really great, the most important is correctly and accurately building the bone-housing and gluing the capsule in, proper movement of the coil/diaphragm and the most of the sound entirely depend on the construction of the housing.