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Looking to make a custom Piezo pickup and preamp to amplify a didgeridoo

Started by Audiological, December 21, 2009, 12:04:47 AM

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Audiological

Hello,

This is my first post here.  I have a Didgeridoo and I am looking to amplify it so that I can run it through a FX Pedal or grunge pedal and then through my bass amp. 

I have been looking into this and it seems as though a piezo style pickup is the best way to go about amplifying this instrument.  I have also heard mixed reviews regarding a preamp for this pickup. 

I have two questions that maybe the folks here can help with:

Is there any specific piezo pickup configuration or type (as in the type of material the piezo is made of) that would be best suited for a instrument that has such low resonance and low frequency properties such as a didgeridoo? 

and

What would be the best way to go about making a custom, small (possibly able to attach it to the instrument size) preamp for this piezo pickup described above? 

This is merely a hobby project and I want to attempt creating something before I go out and buy one of the numerous piezo pickups already designed that might work for this.  Also, I think it would be REALLY great to run that sound through a distortion pedal of some kind. 

Any suggestions?
Thanks
-John

J M Fahey

 :-[ [scratching my head]  ???
What IS a digeri something? ::) he he
A brief explanation, some pictures would help a lot. Same with some MP3  8|

phatt

Quote from: J M Fahey on December 21, 2009, 05:37:17 AM
:-[ [scratching my head]  ???
What IS a digeri something? ::) he he
A brief explanation, some pictures would help a lot. Same with some MP3  8|

Arrh hah! Miss Paloma forgot to tell you about that unique Aboriginal instrument,, :lmao:
http://www.youtube.com/watch?v=KBheMAfz2rc&feature=related

Trick is you have to breath in through your nose while *continuisly* blowing rasberries through a hollow log. A most basic instrument with amazing sound possibilities.
Phil.

phatt

Quote from: Audiological on December 21, 2009, 12:04:47 AM
Hello,

This is my first post here.  I have a Didgeridoo and I am looking to amplify it so that I can run it through a FX Pedal or grunge pedal and then through my bass amp. 

I have been looking into this and it seems as though a piezo style pickup is the best way to go about amplifying this instrument.  I have also heard mixed reviews regarding a preamp for this pickup. 

I have two questions that maybe the folks here can help with:

Is there any specific piezo pickup configuration or type (as in the type of material the piezo is made of) that would be best suited for a instrument that has such low resonance and low frequency properties such as a didgeridoo? 

and

What would be the best way to go about making a custom, small (possibly able to attach it to the instrument size) preamp for this piezo pickup described above? 

This is merely a hobby project and I want to attempt creating something before I go out and buy one of the numerous piezo pickups already designed that might work for this.  Also, I think it would be REALLY great to run that sound through a distortion pedal of some kind. 

Any suggestions?
Thanks
-John

Hi John,, Have you asked what Double Bass players use,, that might be a start.
Phil.

J M Fahey

I *swear* the first thought that crossed my mind was: "this must be another crazy Australian gadget", but since the Forum is so strongly against prejudice of any kind , I said .... "I'll wait ..... maybe Phatt has something to say about it ... " ROFL  :lmao: :lmao: :lmao:
Thanks to bl**dy Telefonica's Speedy my computer hangs with You Tube, but I'll watch it on a CyberCafe/LanHouse/whatever.
Point is: if there is something solid vibrating such as in a guitar, double bass, violin or piano, you can use a piezo, but if the sound comes from a vibrating column of air, such as in a saxophone, flute, organ tube, etc,, you'll have to go acoustic .... and forget about your distortion pedal, except, maybe, later in the mix.

Audiological

Quote from: phatt on December 21, 2009, 09:43:35 AM

Hi John,, Have you asked what Double Bass players use,, that might be a start.
Phil.


Phil,

I was doing some research last night and the biggest issue that I foresee running into is the thickness of the instrument hindering the output from the piezo.  Most acoustic instruments have very thin bodies (in terms of the material of the body, not the actual body).  A didgeridoo however, is quite thick; around a centimeter or more.  Given that this is an authentic one as well (not a knock-off which is bored out with a lathe type tool as opposed to being naturally bored out by termites) I also cannot attach anything inside because it is quite uneven.  

That being said, I need to build a piezo setup that picks up the vibrations of the instrument well and build a on-board preamp that will amplify the signals coming off the piezo pickup.  From the research I have done it seems as though the less vibrations the less output amplitude there is.  It still picks up the vibrations, however, it is a very weak signal, hence the need for the preamp.  

Thanks for the idea though.
-John

Quote from: J M Fahey on December 21, 2009, 10:56:31 AM
I *swear* the first thought that crossed my mind was: "this must be another crazy Australian gadget", but since the Forum is so strongly against prejudice of any kind , I said .... "I'll wait ..... maybe Phatt has something to say about it ... " ROFL  :lmao: :lmao: :lmao:
Thanks to bl**dy Telefonica's Speedy my computer hangs with You Tube, but I'll watch it on a CyberCafe/LanHouse/whatever.
Point is: if there is something solid vibrating such as in a guitar, double bass, violin or piano, you can use a piezo, but if the sound comes from a vibrating column of air, such as in a saxophone, flute, organ tube, etc,, you'll have to go acoustic .... and forget about your distortion pedal, except, maybe, later in the mix.

This is very true (regarding the column of air) however I did find this:

http://www.ellisguitars.com.au/kksound_didgeridoo_pickup.html

This is a piezo pickup designed for a didgeridoo.  I want to make one, as opposed to buying something pre-fabricated so that I can play with different configurations and placements, etc. 

My only real question is whether Piezo materials have specific frequency responses.  e.g.: If I get a piezo pickup, is it going to output what it picks up or is it going to act like a filter of some sort?  Mainly, will it pass through the lower frequency response that the didgeridoo tends to have?

Thanks
-John

tonyharker

Have you thought of using an electret mike element as a contact mike?  These usually have a FET preamp built in all you need to do is supply it with volts from a battery.  They also usually have a high output level.

Tony.

J M Fahey

Hi audiological.
Sorry but now knowing your instrument, the piezo isn't a good idea.
It *may* pickup something, but really the didgeridoo's walls are not meant to vibrate (1 cm thick) , the main sound is not them vibrating but that of the column of air, and to boot, the piezo will be *excellent* at picking taps, scratches, your clothes, coins in your pocket or keys, even your pulse/heartbeat, *anything* that touches or scratches the instrument´s body.
As Tonyharker suggested, an electret mounted close to the end will provide excellent and faithful pickup, coupled to high output and very low impedance , not needing a preamp.
You must fashion a foam support for it to "float" parallel to the end of your instrument, about 1 cm from it.

Audiological

Quote from: J M Fahey on December 21, 2009, 07:16:09 PM
Hi audiological.
Sorry but now knowing your instrument, the piezo isn't a good idea.
It *may* pickup something, but really the didgeridoo's walls are not meant to vibrate (1 cm thick) , the main sound is not them vibrating but that of the column of air, and to boot, the piezo will be *excellent* at picking taps, scratches, your clothes, coins in your pocket or keys, even your pulse/heartbeat, *anything* that touches or scratches the instrument´s body.
As Tonyharker suggested, an electret mounted close to the end will provide excellent and faithful pickup, coupled to high output and very low impedance , not needing a preamp.
You must fashion a foam support for it to "float" parallel to the end of your instrument, about 1 cm from it.

Well, given all that has been said, I am glad I haven't purchased any materials yet.   ;D

When you say "coupled to high output and very low impedance," what do you mean exactly?  Is there anyway to go about this that is better than another?

Also, does anyone have any suggestions as to where I might get the materials to build such a pickup as the electret mic?  What exactly would I need and are there schematics floating around here that I might go off of? 

To be honest, I am very new at making this stuff and I am very unfamiliar with the terms.  So, what exactly is FET preamp?

Thanks again!
-John

phatt

Hi John,
           A FET is a *Field Effect Transistor* they work in a similar manner to a transistor but tend to be a little better with high impedence circuits.

I'm with *tonyharker* or similar ideas.
Any old cassette recorder type thingo 's have electret mikes inside them.
If money is tight you at least can source a lot of stuff for nicks by hacking into old worthless electronic bits. Then you can fiddle with a few different ideas without spending a fortune.

One other option would be those *pressure zone mic's* Tandy used to sell.
*I've never used one* but I've been told you can glue them on a table and they pickup spoken voice very well.
To look at they are just a flat plate about 100mm square with a cable hanging from the side.
Tandy in Australia still sell them I think,,, (I'll assume you are an Aussie ;D)
If they are not in the shop, ask as they may still be at the national store room.

But yes JMF raised a good point ,, you may find a standard or electret mic might deliver a better performance over a straight peizo setup.
Phil.



richfiddler11

I actually have a didgeridoo, a commercial (schatten) stick-on piezo pickup, and a fishman piezo preamp. Long story short, I tried it and can confirm what others have said, that you get virtually no signal from the piezo because the body of the didg is so thick.

Too bad, because you can make a decent,cheap piezo pickup from a $2 radio shack buzzer:

http://www.radioshack.com/product/index.jsp?productId=2062402

You could try putting an electret mic into the end, one of these and a 9V battery will do the job:

http://www.radioshack.com/product/index.jsp?productId=2062216


darwindeathcat

Yes, i also play didj, and I can confirm that a piezo (DIY from radioshack buzzer) will not cut it. Dynamic mics also don't cut it. Your best low cost DIY solution will likely be to use an electret element. You can buy these at Radioshack. You'll also have to build a battery-box to power it.

This link will get you going on a good design: http://www.oldbird.org/mike_home.htm
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