Gain Riding Logic - did it ever sound good?

[par4ken]

Seems to be a Firefox browser issue - just got the 18.3 MB download with the Edge browser.

I'll listen carefully to the test signals tomorrow (I'm using Polk Audio T15 speakers placed a little above ear level [as Polk recommends]), the SQ in stereo imaging (Chase song) was just as you described using these speakers (and verified with Sony headphones).

It does seem like CBS/Bauer made a mistake in selecting the phase angles for encoding LB and RB, if they were reversed, then the SQ to stereo folddown would be as the Audio magazine SQ article diagram shows.


Kirk Bayne

Didn't work for me with Chrome but tried Firefox and it worked. It seems that you have to copy and paste it to your browser, simply clicking on it doesn't work!

 

[kfbkfb]

In late 2021-01, an auto update to Windows 10 corrupted the Edge browser (for a few days), I switched over to the Firefox browser then, anyway, I've got the 2 test zip files now, I'll listen carefully to them this weekend.


Kirk Bayne

 

[Q-Eight]

In my life, I've had three SQ decoders. Well... four if you consider the on-board giblets in my QX-9900. But the outboards were (in order): a Lafayette SQ-L, then a Lafayette SQ-W, then a Tate 101a. The on-board Pioneer stuff doesn't do much. I'm not even sure it works. It does change the sound in the room but, there's no discrete placement of instruments or even the doubled vocals on "Indian Reservation" don't appear in the front channels. They are still quite blurred in the center somewhat.

The SQ-L did better at eliminating vocals from the rear channels than the SQ-W, but the SQ-W was much better at putting instruments in the corners. Back separation was quite good. If something was to appear in FL or FR, you would NOT hear those parts in BL or BR. But there was a lot more (I believe) unintentional back center bleed. Usually drums, bass and vocals.

I'm not 100% sure my Tate is working properly. Since I've had it hooked up, I play with it from time to time but the few SQ discs I have still don't sound like their Q8 counterpart. But it pumps dramatically and everything seems to hinge on whether it can keep the yellow "balance" light lit. If any front center information goes away, Back Right gets much louder than the other channels. And if you're familiar with a Tate, and how often that yellow light flickers, you can imagine how weird it all sounds.

 

[par4ken]

In my life, I've had three SQ decoders. Well... four if you consider the on-board giblets in my QX-9900. But the outboards were (in order): a Lafayette SQ-L, then a Lafayette SQ-W, then a Tate 101a. The on-board Pioneer stuff doesn't do much. I'm not even sure it works. It does change the sound in the room but, there's no discrete placement of instruments or even the doubled vocals on "Indian Reservation" don't appear in the front channels. They are still quite blurred in the center somewhat.

The SQ-L did better at eliminating vocals from the rear channels than the SQ-W, but the SQ-W was much better at putting instruments in the corners. Back separation was quite good. If something was to appear in FL or FR, you would NOT hear those parts in BL or BR. But there was a lot more (I believe) unintentional back center bleed. Usually drums, bass and vocals.

I'm not 100% sure my Tate is working properly. Since I've had it hooked up, I play with it from time to time but the few SQ discs I have still don't sound like their Q8 counterpart. But it pumps dramatically and everything seems to hinge on whether it can keep the yellow "balance" light lit. If any front center information goes away, Back Right gets much louder than the other channels. And if you're familiar with a Tate, and how often that yellow light flickers, you can imagine how weird it all sounds.

I love the Audionics S&IC it has an input balance control and full directional display so that you can see how well it's balanced. The display is great for adjusting the enhance mode as well. It does sound like there might be a problem with your Fosgate.

With the Lafayette SQ-W, apparently early models didn't have vari-blend while latter ones did. I don't think that any of Pioneer SQ decoders were much good.

The

 

[MidiMagic]

How do you phase shift noise and hear the phase-shiftedness. Since psi networks are used in quadraphonic encoders and decoders, the time between different frequencies is different for each pitch.

 

[kfbkfb]

I just listened to the phase shift mp3s using the VLC player [and Polk T15s as mentioned in a previous post] (notes based on the white noise section):

1. centered
2. small shift to L
3. small shift to R
4. poorly localized + small shift to L
5. poorly localized + small shift to R
6. sounds out of phase + small shift to L
7. sounds out of phase + small shift to R
8. sounds out of phase

[The sound has moved towards the channel where the "phase is delayed"] <- yes, my listening test has confirmed this.

Will try the delay mp3 later.


Kirk Bayne

 

[national-kid]

1. centered
2. small shift to L
3. small shift to R
4. poorly localized + small shift to L
5. poorly localized + small shift to R
6. sounds out of phase + small shift to L
7. sounds out of phase + small shift to R
8. sounds out of phase

I sound the same too.
(After all, it is localized in the opposite direction to Sony's announcement document)

 

[kfbkfb]

I wonder when CBS - Bauer - Sony realized that the SQ to stereo folddown had this characteristic (and if they ever considered recalling the existing SQ LPs, modifying SQ and re-releasing the SQ LPs)?


Kirk Bayne

 

[par4ken]

Well I'm hearing the same thing as you guys. I still wonder why/how that could be, it seems to fly against logic. The Haas effect says that the sound will be heard in the direction that it first arrived from. Can anyone offer up a theory of why that is not the case here? I presume that the Haas Effect would've been the reason why CBS chose the phase relationships that they did. Once the standard was set it would not make any sense to change it.

I wonder if swapped phase in the encode/decode process would improve imaging of the 3dB decoder or worsen it? On the one hand left back would be pulled left (in front) in the decode but would that make apparent front to back separation seem less? You would think that both possibilities would've been tried out in the development process. Perhaps the decode just sounded better the way chosen?

 

[national-kid]

I wonder if swapped phase in the encode/decode process would improve imaging of the 3dB decoder or worsen it? On the one hand left back would be pulled left (in front) in the decode but would that make apparent front to back separation seem less?

I think that the performance is almost the same even if the phase rotation direction is opposite. By the way, If play it on SQ4ch (without logic), it will sound like you pointed out because it has a phase relationship as shown in the attachment.

 

[MidiMagic]

Well I'm hearing the same thing as you guys. I still wonder why/how that could be, it seems to fly against logic. The Haas effect says that the sound will be heard in the direction that it first arrived from. Can anyone offer up a theory of why that is not the case here? I presume that the Haas Effect would've been the reason why CBS chose the phase relationships that they did. Once the standard was set it would not make any sense to change it.

I think it depended on the design of the actual phase shifters that were used in the encoders. The fact that one signal phase-leads the other by 90 degrees does not mean that the leading signal reaches the ear first. The psi nature of the phase shifters could delay the leading signal by having it later with the opposite output polarity.

 

[national-kid]

Attached is,
”noise” waveform (5. -90deg.mp3) in which Lch (blue) is 90 degrees ahead of Rch (red).
”noise” waveform in which Lch (blue) is 7ms ahead of Rch (red).
(By the way, the Haas effect is a listening effect for time lag, and I don't think it mentions phase lag.)

 

[kfbkfb]

https://producelikeapro.com/blog/haas-effect/
http://pspatialaudio.com/francinstien.htm

Some info about hearing, might be useful for this thread.


Kirk Bayne

 

[par4ken]

Attached is,
”noise” waveform (5. -90deg.mp3) in which Lch (blue) is 90 degrees ahead of Rch (red).
”noise” waveform in which Lch (blue) is 7ms ahead of Rch (red).
(By the way, the Haas effect is a listening effect for time lag, and I don't think it mentions phase lag.)

Yes but delay and phase are sort of related. The leading phase should be heard very slightly before the lagging phase, So I don't understand why that doesn't seem to work.

Edit: I did some quick testing with pure sine waves and find that the effect is much harder to hear, but still there. The perceived position changes as you move you head or move closer to one speaker or the other. If you move away from the apparent sound image a bit you get the condition of the tone having no precise position the same as if it was totally out of phase. All rather interesting!

 

[par4ken]

I think it depended on the design of the actual phase shifters that were used in the encoders. The fact that one signal phase-leads the other by 90 degrees does not mean that the leading signal reaches the ear first. The psi nature of the phase shifters could delay the leading signal by having it later with the opposite output polarity.

This starts to become mind boggling when you consider that in reality a phase shift of 180° is not exactly he same as a simple phase inversion. We tend to lump the two together. If we take the filters output and simply invert it the opposite "phase" will still have the same "delay" as the non phase shifted signal. That would tend to rule out the "Haas Effect" but how do you explain the actual image shift? This is something that I have never noticed before. It always seemed that phasyness simply blurred (broadened) the image.

 

[MidiMagic]

Yes but delay and phase are sort of related. The leading phase should be heard very slightly before the lagging phase, So I don't understand why that doesn't seem to work.

Edit: I did some quick testing with pure sine waves and find that the effect is much harder to hear, but still there. The perceived position changes as you move you head or move closer to one speaker or the other. If you move away from the apparent sound image a bit you get the condition of the tone having no precise position the same as if it was totally out of phase. All rather interesting!

Here is what I was saying:

I have a device that produces +psi and -j psi signals from the input.

Then it produces the -psi and +j psi signals by running the above signals through an inverter.

Since the -j psi lags the +psi by 90 degrees, the +j psi signal also lags in time behind the +psi because it is a phase-inverted version of -j psi.

Note that if the sound is faded in with the phase relationship already in place, the Haas effect would depend on which waveform reaches the threshold of hearing first.

 

[national-kid]

Note that if the sound is faded in with the phase relationship already in place, the Haas effect would depend on which waveform reaches the threshold of hearing first.

This time, even with a noise waveform with "constant amplitude", I am worried because I can clearly recognize that the sound image is shifting in the direction of the "phase" lag.

 

[kfbkfb]

Is this a new finding, or is there already a scientific explanation of exactly why phase shifted (white) noise (in L and R stereo) is heard in this way?


Kirk Bayne

 

[national-kid]

Is this a new finding, or is there already a scientific explanation of exactly why phase shifted (white) noise (in L and R stereo) is heard in this way?

So far, I have not thoroughly investigated this phenomenon.
(Therefore, I don't know if it is a known theory or not)

By the way, at that time, I only found out that Sony's claim was wrong, and I didn't think about the possibility that it would be inconsistent with the Haas Effect.

 

[kfbkfb]

Possibly involve some University researchers in this investigation to quantify how the human ear/brain combination gives this result (phase shift and directionality) and maybe publish a paper in the AES journal about it.


Kirk Bayne