way to loop 1 second of noise but sound like its not looped

Can you play it backwards and forwards repeatedly, rather than restarting at the beginning?

funny you should mention this! i tried playing it back and then reversing it and it sounds much better and there is a very large reduction in the loop frequency "beat". however there is still an audible "heartbeat" although much reduced

How about cutting the sample into smaller samples, say 16, then randomly re-ordering them on playback?

Mark.

i should also say that I can manipulate the original noise file in anyway I like using windows audio utilities, and then dump it into the playback device. i have a 10 second sample of the noise, and I am cutting out a 1 second chunk of it for the device. but I can cut splice modify those ten seconds however I want to come up with the magic 1 second clip

Does it help at all to crop the wave file such that at the end of the wave, the wave function is as close as possible to Y=0 (with a positive slope - that is, approaching Y=0 from just below the X axis)? And also crop the wave file at the beginning, so that it also begins at or near Y=0, and also with a positive slope? That way, at least the wave file would appear continuous.

I think I would perform an FFT transform of the 1 second burst, discard all components below some minimum inaudible cutoff and then do an inverse transform of what's left to produce the output waveform. The beginning and end should splice perfectly, though it will contain only integer Hz frequency components.

You don't say what your 'device' is.

If its hardware, substitute a feedback shift register and generate the noise.

If is a micro, just generate random numbers and output them.

Luhan

I was going to suggest this. A small linear-congruence PRNG, either in code or in hardware, can generate a sequence of random numbers with a period of minutes, hours or days. It's much better than using 44k words of memory to hold one second's worth of random numbers. I suspect a second's worth of looped random noise will always sound looped, and there's no manipulation you can do to fix it.

Look at the waveform at the start; maybe the first 100mSec, and then look near the end, say the last 200mSec to find something that "matches" in general shape / pattern, and most especially slope and polarity. Those places are where the splice should go, after applying slow attenuation or increase of gain (if necessary) to one end to match amplitude. Use the highest sampling rate possible for the signal of interest as the source for this work; one can always "dumb it down" later if need.

Yes, this is what I found out some time ago. Over a period of a second or less, your ear will always here the cycle.

Luhan

Looping is an art. Sampling synthesizer guys and game sound designers do it all the time. There are programs that have several looping algorithms... some sound better than others depending on the wave being looped... obviously, the beginning and end need to splice together smoothly. If the sound being looped is periodic, like a trumpet note, or an idling engine, you need to make the splice at the end of a cycle. The frequency components at the beginning and end need to be steady... you cant loop the engine if its speeding up... that loop would sound like a sawtooth... speedup, jump back down. The loudness needs to be the same at the beg and end of the loop, or you get a beat at the loop freq... sounds like a washing machine. Cooledit (now adobe audtion) lets you preview the loop and move the loop point around. Best results are by trial and error in my experience.

why not amplify the noise from a zener - that will be good... what do you want it for anyway>