Topic: Stereo cohesion?

I don't know if I'm doing something wrong, but to me it seems that the stereo cohesion in many Pianoteq models is incredibly bad. I'm pretty much only using Pianoteq in mono mode for this reason. (Steinway D, YC5 and K2)

The stereo content of different keys/pitches has very much variation. Some keys are very out of phase, while others are OK and more consistent with each other (at around "33%" width).

Oddly enough, mic placement doesn't seem to affect this too much. Neither does the stereo width parameter (which I'm assuming only boosts the side signal to make the problem worse?). I'm assuming that this problem, if it is a problem, is part of the models themselves.

Is there some other trick to make the stereo width at least more consistent between pitches?

(I'm using Pianoteq 6)

Last edited by joule (12-09-2017 08:47)

Re: Stereo cohesion?

This is exactly why there are multiple Sound Output modes, where you can choose if you want your signal to be mono, stereo, binaural, etc. If you need mono compatibility, you ARE supposed to use the mono output mode.

Hard work and guts!

Re: Stereo cohesion?

joule wrote:

I don't know if I'm doing something wrong, but to me it seems that the stereo cohesion in many Pianoteq models is incredibly bad. I'm pretty much only using Pianoteq in mono mode for this reason. (Steinway D, YC5 and K2)

The stereo content of different keys/pitches has very much variation. Some keys are very out of phase, while others are OK and more consistent with each other (at around "33%" width).

Oddly enough, mic placement doesn't seem to affect this too much. Neither does the stereo width parameter (which I'm assuming only boosts the side signal to make the problem worse?). I'm assuming that this problem, if it is a problem, is part of the models themselves.

Is there some other trick to make the stereo width at least more consistent between pitches?

(I'm using Pianoteq 6)


Could you point to specific instances where you hear variations in the stereo content? (Specific notes in specific presets?)

Re: Stereo cohesion?

Of course, everyone is entitled to his opinion.

Please note, however, that this comment about PTQ6 sounding "incredibly bad" comes from someone making his very first post to this forum.  This lone comment comes in light of dozens to hundreds of accolades to date.

Sounds fishy to me.  Just saying.

Last edited by jcfelice88keys (10-09-2017 21:49)

Re: Stereo cohesion?

Interesting.  Is this "stereo cohesion problem" the same as when I feel as if some instruments, and some microphone set-ups make it sound as if the sound is enveloping you instead of appropriately imaged as the microphone set-up would make you believe? 

For example, some instruments, such as the Grotrian, give a less accurate spatial perception of the piano with many microphone set ups than do others. Even within the Grotrian, there are certain positions that make the perceptual appearance of the piano to be floating around me rather than in front of me or to one side or the other (I am using speakers to the left and the right of my piano (at least I hope it's still there after today's hurricane), and not using headphones – small satellite speakers are to either side of the upright portion of my piano, facing me, while larger speakers are to the left and right of the keyboard, facing the ceiling). Even more curious is that the Player position of microphones from the Grotrian on the Grotrian, as well as the K2 Jazz Player microphones on the Grotrian both make the sound of the Grotrian piano, especially the more midrange and treble sound as if the piano is floating, whereas the microphone set up from the Grotrian Prelude settings make the piano sound as if it's in front of me. With other piano models, such as the model B, there is much less tendency to have the "floating sound" problem, even with the same microphone set ups.

Is this what you are referring to?

- David

Re: Stereo cohesion?

jcfelice88keys wrote:

Please note, however, that this comment about PTQ6 sounding "incredibly bad" comes from someone making his very first post to this forum.  This lone comment comes in light of dozens to hundreds of accolades to date.

Sounds fishy to me.  Just saying.

Good point.

And what exactly is "stereo cohesion"? That seems like a phrase in desperate need of a definition or clarification. It also seems like a "problem" that ears other than those of the original poster need to discern or confirm.

Last edited by Stephen_Doonan (10-09-2017 23:04)
--
Linux, Pianoteq Pro, Organteq

Re: Stereo cohesion?

Most of it is based on impressions... they're subjective. Since stereo sound method of immersion relies on technicals of generating sound which is not found in nature...  the way the brain process the information is by itself different in each individuals.... to create those illusions. Some will not even perceive them at all. There is no objective comparatives of the ''perfect'' stereo sound for one to compare it to... Stereo requires some form of processing of the signal itself based on the constructs specific to each manufacturers. This means that the minute you choose stereo you accept certain level of processing... a tweaking of the actual sound which originally was not there. If you are a purist just deactivate it.

Re: Stereo cohesion?

Lucy wrote:

Most of it is based on impressions... they're subjective. Since stereo sound method of immersion relies on technicals of generating sound which is not found in nature...  the way the brain process the information is by itself different in each individuals.... to create those illusions. Some will not even perceive them at all. There is no objective comparatives of the ''perfect'' stereo sound for one to compare it to... Stereo requires some form of processing of the signal itself based on the constructs specific to each manufacturers. This means that the minute you choose stereo you accept certain level of processing... a tweaking of the actual sound which originally was not there. If you are a purist just deactivate it.


Very well presented.

Pianoteq 7, all the pianos , a  Casio:  Px-560M, PX 3000, (2) PX350's, Mac i27 and MacBook Pro, Focusrite, Scarlette 18/20 and a bunch of speakers and headphones

Re: Stereo cohesion?

Joule: are you using loudspeakers, headphones, or both? I use headphones almost exclusively, and have never noticed any problems with stereo imaging. I do remember a very long time ago having a problem with a sample library - it sounded fantastic through headphones, but terrible through loudspeakers, due to phasing problems.
(and that may have been partly to do with my room acoustics)

Greg.

Re: Stereo cohesion?

Hmmm - I might be hearing what Joule is. For a small example, in Steinway D Prelude, play G#, A, and Bb in octave 3 (middle C = C4) chromatically and repeatedly - there is a noticable timbre shift with each note, which sounds a bit exaggerated.  I know it's normal for each note to have it's own character, but this sounds a bit strange to me.

Greg.

Re: Stereo cohesion?

jcfelice88keys wrote:

Of course, everyone is entitled to his opinion.

Please note, however, that this comment about PTQ6 sounding "incredibly bad" comes from someone making his very first post to this forum.  This lone comment comes in light of dozens to hundreds of accolades to date.

Sounds fishy to me.  Just saying.

The OP never said that PT6 is sounding incredibly bad, he said that the stereo cohesion in many of the models is.
To immediately brand him a ‘fishy contributor' with suspicious intentions for failing to join in the current wave of applause and having the nerve to say something critical instead, is a most unkind and even rather nasty welcome to a new member of the PTQ community, if you don’t mind me saying so.

The more so because, I’m of the opininon that Joule actually makes a very valid observation, pointing to an issue that, in my view, definitely merits attention and further investigation. The sometimes erratic stereo-mono compatibility of many Pianoteq instruments is a chronic problem of the software (one that has been discussed in more than one beta-test) and PTQ’s stereo output is indeed not always the most solid. (The sound quality of many of its stereo patches can get severely compromised when rendered to mono, which is always an indication that there's something not quite right with the stereo to begin with).

And it’s got absolutely nothing to do with ‘impressions’, or ‘ears’, or with the way the brain processes sound or any of that. It’s something, I guess, in the way the sound is generated that, with certain of the instruments, produces a distinctly fragile stereo signal. Simple as that. There’s something about frequencies being-not-quite-in-or-out-of-phase (between both sides of PTQ’s stereo output) that doesn’t always translate very well to mono.

It’s already much better than it used to be though. I still remember, in the pre-v5 days (v5 being the version where the first improvements to this particular problem got implemented) struggling enormously with trying to mix earlier versions of some of the PTQ-instruments, and it was always because of the exact same reason: weak stereo. I can’t count the number of times I had to resort to third-party stereo tools to make PTQ’s (stereo) output behave in a mix.

So, I'm with Joule: the stereo integrity of PTQ's output (for some of the models) is an aspect of the sound that can be improved.



_

Last edited by Piet De Ridder (11-09-2017 07:46)

Re: Stereo cohesion?

dklein wrote:

With other piano models, such as the model B, there is much less tendency to have the "floating sound" problem, even with the same microphone set ups.

It is interesting to see how we can have differents feelings.
I play only with headphones and find the Grotrian Player preset perfect for that. Also I have the same feeling with the YC5 Home preset (which is a player's perspective). I feel immersed in the sound, and like that very much.
Did you try the YC5 Home preset? Is that feel what you call "floating sound"?

Re: Stereo cohesion?

Thanks Stamkorg (and nice to see you involved, Piet). I am currently evacuated from my house due to the hurricane, so I can't try and comment on that particular YC5 preset on my system (I hope that I still have a system, and a house, when I can get back there).  But, since I listen through speakers and not headphones primarily, my choices of presets are often different than that of most people, and my stereo imaging comments are specific to my speaker setup.  When I use headphones I tend to choose slightly different presets than when using speakers, so I am glad that the variety exiats.

More from this for me later when the storm passes, no doubt.

- David

Re: Stereo cohesion?

Piet De Ridder wrote:

I’m of the opininon that Joule actually makes a very valid observation, pointing to an issue that, in my view, definitely merits attention and further investigation ...
So, I'm with Joule: the stereo integrity of PTQ's output (for some of the models) is an aspect of the sound that can be improved.

Thank you, Piet, for adding your comments to the discussion.

And admiration for your compositions and Pianoteq demos.

Last edited by Stephen_Doonan (11-09-2017 14:37)
--
Linux, Pianoteq Pro, Organteq

Re: Stereo cohesion?

Thanks for the replies. Yes, I am using the mono mode with a 3rd party mono-compatible stereowidener. Still, I think this is an issue that should be considered to make Pianoteq usable in stereo.

An example of the problem:

1) Load the YC5 home preset and stereophonic output.
2) Disable the delay and reverb just to make sure that these effects aren't interfering.
3) Bring up a goniometer (phase meter)
4) B-4 will have a stereo correlation of app -0.8
5) D-5 will have a stereo correlation of app +0.7 or more.

You will notice this by collapsing the signal to mono. The fundamental (?) of the B-4 key will pretty much disappear, while the D-5 key stays more intact.

Main point is the following: If the stereo correlation was at least consistent, it would be sufficient to just adjust the S content to taste.

PS. I know that some ears are very sensitive to phasing (I'm not one of them), while others will find the exaggerated stereo compelling. When it comes to production and mixing - negative stereo correlation is de facto bad practice.

Last edited by joule (11-09-2017 16:37)

Re: Stereo cohesion?

Thank you joule for your participation to this forum and welcome here.

The stereo correlation is uniquely a matter of mic position: the closer they are to each other, the closer to 1 will be the stereo correlation of the notes. This happens both in the real world and in Pianoteq. Once the mics are at a certain distance from each other, say more than 20 cm, you cannot avoid having some notes in phase whereas some other notes are out of phase, unless you change the mic position for each note. But that would not be desirable, as you would hear the notes jumping from place to place in the stereo image. The fact that some notes are out of phase is part of the natural physics, and in our piano recordings that serve us as reference, we have sometimes some notes which are so much out of phase that their fundamental almost vanishes. Of course we do not attempt to reproduce those particular notes, I'm just telling that to explain that this happens also in the real life.

In short, if you want to increase the stereo correlation in a given preset, and if you have the Standard version, go in the Sound Recording section, and move the two main mics closer to each other. Note that having a correlation close to 1 is mainly desirable when you want to have mono compatibility, that is, summing the two channels provides a good result, without vanishing overtones. Note also that the mono output provides a clean mono.

Re: Stereo cohesion?

Thank you for explaining, Philippe! If you say that the stereo is proper, I'm happy with that!

I will experiment more with mic placement, and possibly lowering the S channel in post-processing. My aim being to make it a bit less wide without losing too much at specific notes.

PS. Maybe there are other cool tricks as well - like having two different mono pianos slightly panned L and R .. or doing an M/S mic setup by using two instances of PTQ and an M/S matrix.....

Last edited by joule (12-09-2017 08:50)

Re: Stereo cohesion?

joule wrote:

PS. Maybe there are other cool tricks as well - like having two different mono pianos slightly panned L and R .. or doing an M/S mic setup by using two instances of PTQ and an M/S matrix.....

You are perfectly right. You will find on page 47 of the manual four standard mic configurations. If you use the MS technique (M+S and M-S), you will obtain the required minus sign on S via a right click on the corresponding mix matrix cell and setting "Reversed polarity" to 1. (Note that you do not need two instances of Pianoteq, you can do that directly in the Pianoteq Standard mic Recording section.)

Re: Stereo cohesion?

For an example of how to use MS in pianoteq, see the built-in preset K2 Mono Compatible.

Re: Stereo cohesion?

This discussion contains some very interesting information. Thank you Philippe, joule and others.

--
Linux, Pianoteq Pro, Organteq

Re: Stereo cohesion?

Joule- Are you using a subwoofer, or is there anything unusual about your speaker positioning?

Re: Stereo cohesion?

tfort wrote:

Joule- Are you using a subwoofer, or is there anything unusual about your speaker positioning?

I'm mainly using headphones (DT-1770 or HD-650), but it's not so much a matter of listening environment in this case. The effect comes from the source which can be verified with a phase correlation meter, or by just collapsing the signal to mono and listening for cancellations. As Philippe pointed out, it's a realistic effect.

Anyway, I've tried some M/S setups in PTQ now. It's interesting to use for a different kind of stereo, but sounds kind of boxy.

Last edited by joule (12-09-2017 16:11)

Re: Stereo cohesion?

M/S reproduction is the idea behind the CenterPoint Stereo SpaceStation (http://aspenpittmandesigns.com/spacestation-v3/). I've not heard one, but read the effect described as "stereo-like" sound from one speaker unit.

Re: Stereo cohesion?

Joule,

I sometimes hear the same type of phase issue with Garritan CFX, and other VIs based on recorded samples of a piano. It can be particularly obvious playing scales with headphones (on certain sections of the keyboard); a few neighbouring notes seem to shift radically between the L & R earphones. But looking at the individual waveforms the amplitude change is not so obvious. And some users I have spoken with don't notice this at all.

I spoke to the Garritan techs and they provided an answer similar to that of Philippe.

Different mics and positions helped me address that "phase issue" in Garritan CFX (although frankly I haven't noticed the phase issue in PianoTeq). Using speakers rather than headphones helps as well. Using different headphones can help also. Or just using a real acoustic piano.

I would also like to take this opportunity to note how slick PianoTeq's "Delay Compensation" button is (mics section).