How will this waveform sound?

[JimRayden]

I want to ask any opinions before I hit the breadboard with my new top-secret circuit.

I did a computer sim yesterday and the waveform I was looking at was too funky to be clean and too smooth to be distorted. Firstly, it was awfully asymmetrical - the length of the positive swing was like half of the one of negative (i.e. the signal spends much more time in the negative zone). But it didn't look like it was squished or saturated, either.

According to my experimentations with clipping diodes, with one side clipped, it isn't too obvious to the ear, at least not to the degree of double-sided clipping (or "squishing").

I assume it will sound quite clean but with certain overtones because of that jumpy positive swing.


I'm sorry there are no pics, I'll get some as soon as I get home.

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Jimbo

[brett]

Hi

Firstly, it was awfully asymmetrical - the length of the positive swing was like half of the one of negative

Hmmm...  As you've noted, double on one side (ie 2:1) sounds only moderately different (mostly a touch "sweeter") to a clean signal.  Hence many people use three diodes (2:1) in tubescreamers, D+, etc.

What will it sound like?  If it's not very distorted and 2:1 asymetric, then for a constant tone, it will probably sound like a faintly sweet version of that tone.  The distiortion won't be noticable unless it is either at a high level (20% and up) or contains some nasty non-harmonics (in which case a % or two might do).

A final suggestion: one of the things that makes good overdrives and distortions is their dynamics.  This releates to questions such as: At what signal level does distortion become obvious?  How does a typical envelope "rise" and "fall"?

I hope it works out well for you.

[DDD]

1. The sound will depend heavily on the time period (i.e delay) necessary for the signal to be distorted in the described way (i.e. attack response). Since there is an asymmetric clipping there, some initial charges\discarges of the coupling\blocking capacitors are quite expectable - hence sound attack may be affected with this factor.
2. Asymmetric clipping usually causes considerably audible intermodulation distortion (that's why Tube Screamer, DOD 250, B@ss effects and many others have symmetrical clippers)

[JimRayden]

Thanks for the replys.

Here's the promised osc. reading:

http://www.playoutband.com/stuff/output.jpg

Notice the "1V" pic. It looks like the bottom is squished but it's too DAMN round.

I might do some more experimenting to bias the circuit for a bit more symmetricy.

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Jimbo

[JimRayden]

Anyone?

The question is, should it sound good or should I play around with the circuit a bit more.

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Jimbo

[Gilles C]

What you have to remember is that a guitar has a more complex signal than a sine wave.

So your circuit will begin to affect the high peaks first, and color the sound of the guitar. Then the stronger the signal, the more it will be affected, and the more it will start to distort.

So it should sound IMO, because it will change the signal progressively.

But to be sure, you'll have to try it...

Gilles

[JimRayden]

Yes, I am aware of the signal complexity and high frequencies, I just wanted to know what you thought about the scope readings.

So it should sound IMO, because it will change the signal progressively.

I don't think I know what IMO used as an adjective stands for...

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Jimbo

[Gilles C]

On My Opinion...

Gilles

[TELEFUNKON]

why not listen?

[JimRayden]

On My Opinion...

Gilles

Not to be picky but could you rephrase "So it should sound In My Opinion, because it will change the signal progressively.". I think you left out a very very important adjective.

why not listen?

I wanna get it right in the sim, then start building. It's quite a bulky circuit. Currently I'm messing around with 18V. I'll keep you updated.

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Jimbo

[brett]

This looks a bit similar to what I got when I accidentally mixed a tube's plate and cathode signals a while back.  Some cancellation at first, then domination of the plate output as a classic overdrive.  It sounded kinda ok.  In fact, it's sitting on my bench awaiting further experiementation.

So go for it.  There's no distortion police who arrest people that design mediocre distortions.  If there were, I'd  be doing time with hard labour.

[Gilles C]

   Oh, I got it now...

It should sound GOOD In My Very Humble Opinion... 

[JimRayden]

So go for it.  There's no distortion police who arrest people that design mediocre distortions.

But instead of police, there's Sven. He hates people who design mediocre distortion.

  Oh, I got it now...

It should sound GOOD In My Very Humble Opinion... 

I can now merrily proceed.

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Jimbo

[DDD]

As per the oscillogramm the duty cycle depends on the input voltage. It's very good in general.
If the circuit processes the sound attack properly, the sound will be beautiful.

[rocket]

I think it looks like the output of a fuzz face

[JimRayden]

You're right! It never occured to me. Now let's hope it'll sound like a 'rounded' FF, I'd love that character.

(Geesh, I'll need a bigger breadboard for this monster.)

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Jimbo