Cherry Audio Forums

Very cool and it makes complete sense after your demonstration. Thanks for that!

d.

Sample delay already in the works... I'd been interested in updating the addition fader for a bit, so I just went from there.

Wow! No time wasted. This is terrific. Thanks for your efforts.

playertron wrote: ↑Sat Feb 18, 2023 5:47 pm So, for instance, if you are mixing different sequenced parts like synths/drums/bass/etc, you needn't think about this at all. And, if you're submixing signals within a patch, you only (maybe) need to worry about something like mixing raw synced oscillators running above something like C8 (which of course might also run into other artifacts from digital audio anyway).

Well, if you're only talking about fundamental frequencies, you'd be correct. However, anything other than a pure sine wave has significant energy in its harmonics.

Here's what happens when you mix a simple sawtooth oscillator at C4 (~261Hz) with a three-sample delayed copy of itself. You can hear a big difference in tone due to the notch which appears at 8kHz. C4 is four octaves below C8 (i.e. 1/16 of the frequency).

YouTube demonstration of multi-path delay.

Hi Grant,

II'm wondering how much impact cancellation caused by propagation delay has in the real world. For instance when listening to music coming from a pair of loudspeakers if I move my head or even walk about in the soundfield then I don't notice massive changes in sound perception despite the delay between the left and right channels varying enormously.

I understand there's a difference between raw signals being mixed together and an acoustic environment but even in a dead room or the open air I don't hear any significant changes in timbre happening. And plugging up one ear doesn't change this. I've not thought about this deeply, so am curious to learn if I've missed something.

Colin, actually, you do hear changes; you're just used to them. Frequency-dependent volume changes are major laterality cues.

Reid

Yes Reid, but that's why I used hedged langiage like massive and significant changes.

My conjecture is that such subtle effects are essentially imperceptible outside of fairly artifically constructed situations. Otherwise stereo would never have caught on.

It's part of a philosophical argument I have with people taking an overly engineered/technical approach towards electronic music production when I believe more focus should be directed towards things that have greater impact from an artistic perspective. In an ideal world these things would not be mutually exclusive but in reality developers have finite intellectual resources available. It's just my personal view and sometimes I raise it because I see an inbalance in approaches.

One of the things I admire about the Playertron modules is that they are so non-conformist.

So, I was recently working on a somewhat unique oscillator with a very specific sync capability, and certainly, it provided a case where even a well-trained ear wouldn't hear a difference in sound with the one sample delay that occurs b/c the sync pulse goes through a wire, but which would compromise one specific application where two copies could be wired to create a 4-part "quadrant" waveform composite (sorta making this phrase up rather than writing tons more, but it doesn't really matter) - anyway, enough steps further and there was an audible artifact, and I found myself building in some compensation. Point is though, you'll know when you need to worry about a delay of a few samples b/c you hear something you specifically don't want. When it gets to the point that you're mixing waveforms with precision requirements, I'd advise skipping mixers altogether and using oscillators with built in amplitude control. Even then, sync can mean a number of things to various oscillators and even the particular phases of various waveforms within a single oscillator isn't universal - it's surprising, but also not

This stuff does come up in the real world too (phase inversion is the biggest issue, noise is small but real, delay is usually insignificant if all analog while slightly present w/ digital, but there's a lot in between), where you can hear differences b/c of these sorts of issues, but ultimately ask yourself if "difference" means "problem" b/c sometimes it does and sometimes it doesn't.

Anyway, I did implement a compensation delay in the Addition Fader and, while unnecessary for normal audio mixing duties, does allow you to get into some pretty interesting territory with mixing oscillators because you can adjust the phase, up to 127 samples and create a diverse set of micro-differences in tone, both for precision adjustment and for interesting effects. Since I already had the basic update ready to go before any of this discussion, I'll actually be able to publish the Addition Fader 2 shortly...

Thanks for some great food for thought!

ColinP wrote: ↑Sun Feb 19, 2023 6:15 pm Yes Reid, but that's why I used hedged langiage like massive and significant changes.

My conjecture is that such subtle effects are essentially imperceptible outside of fairly artifically constructed situations. Otherwise stereo would never have caught on.

It's part of a philosophical argument I have with people taking an overly engineered/technical approach towards electronic music production when I believe more focus should be directed towards things that have greater impact from an artistic perspective. In an ideal world these things would not be mutually exclusive but in reality developers have finite intellectual resources available. It's just my personal view and sometimes I raise it because I see an inbalance in approaches.

One of the things I admire about the Playertron modules is that they are so non-conformist.

Thanks for the shoutout at the end there

ColinP wrote: ↑Sun Feb 19, 2023 11:00 am Hi Grant,

II'm wondering how much impact cancellation caused by propagation delay has in the real world. For instance when listening to music coming from a pair of loudspeakers if I move my head or even walk about in the soundfield then I don't notice massive changes in sound perception despite the delay between the left and right channels varying enormously.

I understand there's a difference between raw signals being mixed together and an acoustic environment but even in a dead room or the open air I don't hear any significant changes in timbre happening. And plugging up one ear doesn't change this. I've not thought about this deeply, so am curious to learn if I've missed something.

Hi Colin,

I might be something of an outlier, but I insist on sitting (or lying down) right in the sweet spot when listening to immersive music over stereo speakers. In fact, that's how I came up with the name "Under the Dome" for my band. Here is the explanation for its origin from our old GeoCities home page! (Yes, we've been on the go THAT long! )

"Imagine the following scene...

The listener is lying on the floor, exactly equidistant from both speakers and has made sure that the left-hand speaker is closest to his left ear and that the right-hand speaker is closest to his right ear. This last point might seem self-evident, but it is quite possible to lie down between speakers and to face in the opposite direction from which you would normally be listening to your stereo system.

Now, put a good 'immersive' track on and position your head in such a way that sounds which are meant to be heard in the centre of the stereo field seem to come from inside your head or directly above it...you've found yourself Under the Dome! Dim the lights, close your eyes and follow the sounds as they appear out of thin air."

Chuck Van Zyl also described it in his own inimitable way on the Star's End website:

Throughout his many profound "eyes-closed" Electronic Spacemusic listening experiences, "the sounds seem to take on an almost solid, tangible quality, visualized as a kind of firmament existing in space. But it seems however, that there is a finite boundary beyond which these sounds cannot exist. If you imagine this boundary as a radius, beginning at the listener's head and radiating out in three dimensions, it's easy to visualize a hovering hemispherical shape - which ostensibly places the listener, under the dome".