RC jet sound effect generator project

[audioguru]

The "op" in opamp is "operational". It can have a lot of voltage gain so its input voltage is tiny or it can have no gain so its input is as much as its supply voltage.
A real speaker weighs a lot more than only 50 grams plus it needs a lot of battery power.

 

[FMD]

I am gonna give it a try with the greeting card setup and see how it works. Seems loud enough. I dont know if the transistors change that. The card setup comes in well under 50 grams. Did you look at the Benedini Sound system by any chance? Looks like they have a larger 3-4" magnetic speaker system with a power amp. Do you have any experience building circuits?

Thanks,
FMD.

 

[audioguru]

The Bendini system sounds good because it uses a real (heavy and powerful) speaker, not a little piezo squeaker.
I have built and designed thousands of circuits that work well.

 

[FMD]

Here is the schematic I was referencing.

I can wire a house, but this thing kinda blows my mind. The quad amp setup, is that the same as what you would get by buying an LM324 or similar device? I wish I had a picture of the finished product.

http://cappels.org/dproj/wng/wngenerator.html

Hey, thanks for all your info,
FMD.

 

[audioguru]

Your link does not work.
An LM324 is a quad opamp which has 4 opamps. Look at its datasheet.

 

[gabeNC]

Do you have any experience building circuits?

Sorry that question pointed to audioguru made me laugh. Thanks, I needed a smile today.

 

[FMD]

Sorry that question pointed to audioguru made me laugh. Thanks, I needed a smile today.

It wasn't intended as a jab. Hope it was not received that way.

The link is functional now. At least it was a few seconds ago. It took awhile to get the scope of this project established but it was interesting. I have, i think, explained it now. The objective is to build a sub 50g noise generating circuit that is broadcast over a small speaker. This weight is not inclusive of the power supply.

I think that schematic shows an appropriate design, but I have some study to do before I can match that diagram to the what needs to be done.

Any help is appreciated.

 

[audioguru]

I have never heard a jet airplane that makes a sound like "ssssssss".
Frying onions maybe?

 

[FMD]

Even a sssssssstealth? If that method of creating noise cannot produce static with enough edge... does the audio guru know of a different way? I remember having a walkie-talkie as a kid. That would have been RF noise correct? That seemed like the right tone for a jet-like sound. Now, that probably used a small magnetic speaker, but i'm sure a piezo could produce some sound too. Hey, it is all a matter of compromise. Just remember this is a little jet making little sounds. I'm not shooting for the full afterburner out of the piezo. We beat that one into the ground already.

FMD.

 

[audioguru]

A real big magnetic speaker produces most frequencies, not just the little high frequency squeaks from a piezo transducer.

On the internet there are many recordings of jet aircraft sounds. They sound real when heard on my pc magnetic speakers but will sound like little squeaks on piezo squeakers.

 

[FMD]

How 'bout a 40-50mm magnetic speaker. They weigh in around 40 grams and are really inexpensive.

 

[audioguru]

How 'bout a 40-50mm magnetic speaker. They weigh in around 40 grams and are really inexpensive.

A 2" inexpensive magnetic speaker is garbage. A 4" fairly expensive heavy speaker is beginning to sound good.

My little pc speakers sound pretty good. They are 3" and have huge and heavy magnets. Their enclosures are pretty big. The speakers look like this:

 

[FMD]

Then we would run into weight problems both with the speakers and the amplifier. I still think the doppler effect is the key with a lightweight low power system. Earlier I posted about the sound effects kids make (or adults for that matter) for a jet. I dunno, kinda sounds like static to me. There is a way to make a noise producing circuit with a small speaker. Granted it won't have the low frequency rumblings of a real jet, but a close pass even in a glide will sound pretty good to a kid as the jet passes by.

 

[Sceadwian]

Why don't you just strap a bunch of whistles to the air frame?

 

[FMD]

You know, oddly enough I tried that once. Doesn't work. Besides, too much parasitic drag and wrong sound. Would laying this out on a breadboard, if that is the correct term, be helpful? Seems like it would. What about the zener diode source of noise? Seems simple enough.

 

[FMD]

Check this out..

https://www.electro-tech-online.com/custompdfs/2010/01/noise_generator_ac7ac-style.pdf

man, that is ugly, but no wasted weight there.

 

[mneary]

Your site requires a name and password.

Check this out..

https://www.electro-tech-online.com/custompdfs/2010/01/noise_generator_ac7ac-style-1.pdf

man, that is ugly, but no wasted weight there.

 

[FMD]

When I click on it a pdf file appears. No password required.

 

[audioguru]

The noise generator circuit is designed to make radio noise and has tiny coupling capacitors so its output at audio frequencies will be poor.

 

[Mr RB]

Ok if you are going to do it then maybe it's time to think outside the box.

Instead of magnetic speakers you could use piezo disks, these are light and you could use more than one to increase the sound producing area. You are after a high freq noise anyway.

Then instead of thinking about an "amp", why not generate the pink noise directly with a high power digital circuit? Battery weight is at a premium, so you could make a push-pull noise generator using FETs, it doesn't need to have any analog amplification as such, just to run full bore digitally with a basic digital noise source (counter IC?) controlling it.