Inverted phase and Q1

[andy74]

Hi,

I seem to be the only one to be confused with these magical settings of XX: Q1 and inverted phase.

Peter,
I could not find a good explanation of what Inverted phase and Q1 setting actually does,
Only common phrases about its influence on SQ.

One of my confusion is how inverting the phase would still be "bitperfect". You change the data when inverting the phase don't you?
I need to understand what is going on when I change some setiing.

And the main question is what is Q1 and how the h... can it lead to the inverted phase? That is the big mistery for me.

Please clarify.

thanks
Andrey

[PeterSt]

Hi Andrey,

Well, maybe you are the only one who wants to know really, or wants to understand really ... or ... But here is my kind of answer :

Whatever the Q1 is set to, that's bit perfect.
The Invert box, when checked, of course is not. But it's nothing more (or less) than indeed inverting the phase. So revert that back (at the output) and you'd have bit perfect again. Now why ...

As it occured, once the Q1 goes over "a hurdle" indeed it seems that the phase gets (at least) acoustically) inverted. I could present you with a theory for that, but it would be a kind of blabla, because I would have to make it up. Anyway, I am not the only one perceiving that (and to me it is kind of logic, but that's the blabla thing ). So, that's why the Invert emerged ... to counteract that.

In the mean time, a few of us (amongst those, me) think that Inverting the phase has different "effects" than just inverting the phase.
Sidenote : inverting the absolute phase (that's what it is, so nothing about left/right stuff) is something only few people can hear. It is about things starting to suck instead of blow, and the other way around. You can maybe imagine, that when this is so, at the higher frequencies a too sharp "blow", will be softened by sucking instead. So, it does something to the sound which possibly is perceived as better to the ears/mind.

Of course all starts to be rather confusing if you again think about the hurdle as mentioned. Thus, e.g. when Q1 goes from 10 to 9 to 8 to 7 ... suddenly with Invert checked it sounds better. But is the phase acoustically now inverted or not ?
This all is related to "what is the base setting anyway", which we don't know, since we did not even know it could change.

Also think about "absolute phase" as something that's in an instrument, like a drum which obviously should start with a blow. However, since at recordings not much attention is payed to how microphones (or mixing consoles) are connected according to absolute phase, the various instruments/voices are recorded with mixed absolute phase. So there's no one best setting for "Invert". Still, if you listen to the difference, in general (so over various albums) one setting is better than the other, and is related to the Q1 setting.

However, there is no technical relation to Q1 whatsoever in the program, but in practice / acoustically there is ...

Peter

[andy74]

Thank you very much. It is now clear.

What about Q1. in general words what does it do? Or it is proprietary?

[PeterSt]

All I can say is :

It is a non-lineair (explicit) means of influencing jitter, or "jitter effect" when measured at analogue-out of the DAC.

The way Q1 works is "one way" of doing it, while there are more methods in my mind (Q2 will do that in some future).

In either case the passing of data is bit perfect (until things get over driven and distortion occurs).

[andy74]

Peter,

I still don't understand what can do such thing to sound as if phase inverted.

Q1 at -3 sounds as if sample feeding rate is too low so that some samples are lost = clicks and pops dropouts
Q1 at 30 sounds as if sample feeding rate is to high so that some samples are skipped ahead = like vynil record jumps forward

And at Q1 29 I can clearly hear inverted phase (invert is not checked). Drums sound funny on 'Tallica's "Kill'em All"
So I have to check the invert. And that bothers me a lot, that I have to mess with data.

Something is wrong here with Q1.

Andrey

[PeterSt]

Hi Andrey,

The effects you describe are not related to what and how Q1 influences, nor does it imply that Q1 is wrong;
What happens is that you cross boundaries, btw those boundaries being different for everyone.

If you could set the buffersize of your DAC, you would know (or better understand) what could be happening : the buffersize does not cope with e.g. the samplerate. Although all is very logic, it is hard to explain (for me anyway), but maybe the easiest way to explain is this :

When the sample rate is doubled, twice as much data has to pass the DAC. This is an easy one.
Not easy to see, is that this requires a twice as large buffer at the same time. I mean, the twice as much data, passes twice as much just as well, so why needs the buffer to be larger ? but it is so ...

Similar things happen when you overdrive Q1. You can overdrive it towards the bottom e.g. -4 (say, the buffer needed there can't be smaller than it physically is), and towards the top e.g. 30 (say, the buffer needed there can't be larger than it physically is).

Of course I can imagine that you can't understand *why* this is so, but please trust me *that* it is so.
Anyway you need to find the boundaries for your chain (plain distortion, where skipping/repeating of even 1 sample I call distortion), and in between those boundaries you can slide the Q1.

What makes it extremely more difficult, is that -as the past proved- the boundaries vary per XX version. To me in the end this is logical, but not much convenient. Anyway this is because of working with super-low latencies, and in fact the Q1 "setting" becoming instable because of environmental influences. As I said elsewhere, the frequency of refilling the DAC's buffer we work with comes down to once per 1 ms. This is the same as the latency of 1ms with which every audio mastering engineer would love to work with. Here, however, things go even way further, because here it is not about pushing samples through in a short burst (like a midi keyboard's note), but a constant rate of that 1ms and NOTHING allowed to go wrong (for in fact hours).

I hope I am not too misty(fying), but the main thing is : nothing is broken and all is to be expected.

Peter