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wazupwiop 22nd August 2011 01:34 AM

Piezo Pickup Experiment
 
Hey all,
Over the next few months, I am going to be experimenting with piezo pickups. I am sure that many of you have toyed around with acoustic guitars and a piezo, but I am going to take it one step farther, with a little bit of applied science.

I don't know if you have ever heard of a man named Peter Sesselman, but he makes guitar pickups from piezos, and he has his craft down to a science.

Piezos are affected by three things: vibration, bending, pushing and pulling. I have talked to Mr. Sesselman and watched some of his youtube videos. He talks about the design and construction of his piezo pickups, and this is what I plan to experiment with.

Vibration is the first stimulus of a piezo. Often times, this will be the main source of sound from a piezo-based pickup. the issue with this is that it is the weakest stimulus out of the three stimuli I mentioned above; however, if you combine the effects of the other two stimuli with the vibration, you can tweak the dynamics of a piezo-based pickup.

To stimulate the pulling and pushing of a piezo, I am going to put a counterweight on one side of the piezo. Peter Sesselman describes this in his videos, along with the rest of the things I will be talking about. The counterweight controls the treble frequencies of the pickup. I am going to try different weights of objects and post the results. I am going to try coins, metal washers, and bolts.

To stimulate a piezo through bending, only the center of the piezo should be mounted by a small dot of adhesive. A cap can be placed along the edge of the piezo to slightly bend the piezo as you play, creating bass frequencies. I am going to take a dowel rod and make a small cap. I am going to test different amounts of wood and etc. It should be interesting.

The piezos I ordered should be here this week. I will hopefully get some testing in, but I have to keep up with my school schedule. I will post results as I go. Stay tuned, this should be pretty intriguing.

Printer2 22nd August 2011 02:04 AM

Hope you have a preamp.

wazupwiop 22nd August 2011 02:12 AM

With this design of a pickup, a preamp isn't necessary. As I mentioned, the vibration of the piezo is the weakest stimulus out of the three stimuli that affect a piezo. The bending (the strongest force) and pushing force on the piezo really boost the output of the piezo (2-5x).

Think about this. Piezos are used in buzzers. These buzzers utilize the piezo to its full potential. Those little buzzers are REALLY loud. Some can reach up to 100 dB.

By using all three stimuli, I can minimize the need for a preamp. I will have to do some testing, but we will see.

Nigel Goodwin 22nd August 2011 11:32 AM

Quote:

Originally Posted by wazupwiop (Post 2680965)
By using all three stimuli, I can minimize the need for a preamp.

No you can't , you MUST use a very high input impedance preamp, guitar amps etc. aren't usually high impedance enough. It's not gain that's the problem, it's the impedance.

But to be honest, just going from what you've said, the entire thing sounds a bit of a scam.

wazupwiop 22nd August 2011 11:52 AM

Quote:

Originally Posted by Nigel Goodwin (Post 2681276)
No you can't , you MUST use a very high input impedance preamp, guitar amps etc. aren't usually high impedance enough. It's not gain that's the problem, it's the impedance.

But to be honest, just going from what you've said, the entire thing sounds a bit of a scam.

I believe that Mr. Sesselman's work is not a scam. People have reviewed his pickups on multiple with 4 and 5 star reviews. I have researched this on other websites about the bending and pushing effects on piezos. The science is there, but I am going to do some testing. This is just kind of a fun experiment. My guitar already has electronics, I am just messing around for fun and scientific purposes. If it doesn't work, it doesn't work.

If Mr. Sesselman's work is a scam, it is about to be exposed for what it is. I am not biased, this just sounded like fun and I thought I would try it. It will be interesting to see what happens, so stay tuned.

Most modern amps can handle high impedances if memory serves me correctly. In fact, many guitar amps have Hi and Lo inputs to provide an input to suit the needs of modern equiment that operates at high impedances.

That said, older amps (Pre-80's) may have an issue with higher impedances due to design. I am not going to be using a 30 year-old amp to test the piezo pickups. I am going to be using a solid-state Line 6 amp. I have seen people on youtube plug straight in to an amplifier with no issues to speak of. If I actually need a preamp, I have the electronics skills to make one. I don't think I will though.

Nigel Goodwin 22nd August 2011 12:19 PM

Quote:

Originally Posted by wazupwiop (Post 2681286)
Most modern amps can handle high impedances if memory serves me correctly. In fact, many guitar amps have Hi and Lo inputs to provide an input to suit the needs of modern equiment that operates at high impedances.

Your memory doesn't 'serve you right' - you have it the wrong way round, modern amps have the normal medium impedance input, and a low impedance one specifically for active guitars.

Modern equipment doesn't operate at high impedances, it's generally a poor idea.

wazupwiop 22nd August 2011 01:40 PM

Okay, do you have any suggestions for a good DIY piezo preamp?

wazupwiop 22nd August 2011 04:26 PM

Check this video out and tell me what you think:
peter rambles on about piezo acoustic guitar pickups and how they work DIY - YouTube

wazupwiop 22nd August 2011 05:51 PM

Update: I am going to build Don Tillman's FET preamp. It should be interesting. People have a lot of rave reviews about it.

tinitus 22nd August 2011 06:44 PM

Quote:

Originally Posted by wazupwiop (Post 2681571)
Check this video out and tell me what you think:

he is certainly trying hard to explain it :D

well, I think all who are dedicated to solve the problems of amplifying acoustic instruments are serious people


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