Involve Surround Master - original & V2 - "Pumping" issue

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Sonik Wiz

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In pumping, could I be using the wrong term ? What's happening is during certain music passages, the high end sounds like it's fading in & out along with a little sprinkle of distortion. I thought that's what pumping meant but maybe not. Also, does the fact that unplugging the opposite channels input to the SM stops it mean anything ?

If you unplug one ch it means there is no amplitude or phase difference anymore for the unit to detect & enhance separation. Unplugging the right ch is the equivalent of center left where Lf=Lb.

I can't hear what you hear but I'd still suggest what you are experiencing is the situation of hearing the Involve separation magic doing what is does abnormally listening to just a fraction of the soundfield. Lemme put it another way. Say the recording has a lead guitar panning around in a circle or even just between left front & right front. If you listen to just left front, you will hear the guitar fade in & out as it pans around to the other speakers. That might seem like pumping.

All separation enhanced matrix decoders will produce some artifacts under certain conditions. SQ in the various Logic circuits was one of the worst. Sansui's QS Variomatrix was one of the best. Involve's updating of the original concept is even better.
 

junh1024

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With surround upscalers, you either get pumping (avoids artefacts) or artefacts (avoid pumping), due to the nature of the upscaling process. Pick your poison.
 

kfbkfb

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Could be a problem with the stereo input to the SM decoder, maybe something as simple as a cable that isn't making good enough contact, or making intermittent contact.


Kirk Bayne
 

Sonik Wiz

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My terminology:

Artefacts (metallic sounds), as opposed to pumping (wideband gain changes)
Well maybe your terminology is correct for an artefact. But an audio artifact is best described as a simply a sonic error. It could be metallic sounds or pumping or intended as fuzz added to a guitar. It is a rather large umbrella term with a lot under it. I have heard pumping & other artifacts from both upmixing stereo to quad or 5.1 or proper quad recordings over 50 years of listening. I don't think there is a trade off between metallic sounds or pumping.
 

Lance7489

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Could be a problem with the stereo input to the SM decoder, maybe something as simple as a cable that isn't making good enough contact, or making intermittent contact.


Kirk Bayne
Switched cables, CD players, even sound systems. Also, same thing is happening with 2 different surround masters. I originally thought it might be a bad cable or a bad RCA jack, but no such luck.
 

Lance7489

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If you unplug one ch it means there is no amplitude or phase difference anymore for the unit to detect & enhance separation. Unplugging the right ch is the equivalent of center left where Lf=Lb.

I can't hear what you hear but I'd still suggest what you are experiencing is the situation of hearing the Involve separation magic doing what is does abnormally listening to just a fraction of the soundfield. Lemme put it another way. Say the recording has a lead guitar panning around in a circle or even just between left front & right front. If you listen to just left front, you will hear the guitar fade in & out as it pans around to the other speakers. That might seem like pumping.

All separation enhanced matrix decoders will produce some artifacts under certain conditions. SQ in the various Logic circuits was one of the worst. Sansui's QS Variomatrix was one of the best. Involve's updating of the original concept is even better.
Maybe you're right. Maybe it's just the "nature of the beast" with decoders, although I know I'm sometimes hearing a little distortion, especially out of the center channel, which is harder for me to tolerate than what I refer to as pumping. Like I mentioned, I'm extremely hard to please when it comes to sound quality, maybe I'm just expecting too much out of a decoder. I'm applying 2 channel standards to this but that could be unreasonable. There is no pumping or distortion when I play RM or QS encoded recordings using the "involve" format, only pumping with standard stereo recordings. That's why I was always a fan of discreet surround formats (CD-4, open reel tape, SACD surround, DVD audio surround etc).
 
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chucky3042

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In pumping, could I be using the wrong term ? What's happening is during certain music passages, the high end sounds like it's fading in & out along with a little sprinkle of distortion. I thought that's what pumping meant but maybe not. Also, does the fact that unplugging the opposite channels input to the SM stops it mean anything ?
That is a form of pumping. Do the input channel swap and see what happens
 

Wunlow

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While I'm generally a fan of higher matrix separation designs (Army of Quad's previous Involve SQ vs the Tate blind A/B test confirmed this for me) there was one track in that comparison where I distinctly preferred the Involve decoding as in that particular case it had no pumping. Someday it would be cool to have an advanced decoder with adjustable separation adjustments so the user's own taste and the given content could be tailored as needed.
 

J. PUPSTER

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I wonder if anyone else has experienced this with Involve's Surround Master. To set the record straight, I'm a extremely fussy music listener .............I own both the original & a V2 which I use both on 2 separate systems, The SQ mode is GREAT for all the 70's SQ stuff. The problem I'm having is with the "involve" mode. For TV it's excellent, for stuff encoded in RM or QS it's excellent, but with stereo music, I hear a lot of "pumping" going on, mostly with the center & front left channels. If I switch from 5.1 to 4.1, the pumping is diminished, but still some. A lot of songs sound fine but SOME display this slightly distorted, pumping thing in the channel's I've mentioned. The best example I can think of is Elton John's "Someone saved my life tonight". You really hear it when you isolate those channels (turn all others down & just listen to one) It does it in BOTH of my systems, on the same songs, so I don't think I have anything hooked up improperly. .....Has anyone noticed or experienced this ?? .......... Any suggestions ? (I don't use the RCA cables that came with the units, could that be it ?) ...... Like I mentioned, I absolutely LOVE what it does with the 70's quad formats (SQ, RM, QS etc), but when playing straight stereo recordings using the involve mode, the separation is great, but this issue really dampens my enthusiasm.
Perhaps you could "Attach" a small section of audio that you feel has the most "pumping" and also be sure to include the exact song source and all settings through your chain. The current limit for attach files is 20480 kb. If you have any experience with a simple DAW like Audacity etc.?

I have never noticed any pumping from my Smv2.
 

Lance7489

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Do you have a Dolby Pro-Logic decoder (it's a variable matrix type decoder too) to try and see if this audio artifact also appears?


Kirk Bayne
No I don't. I use a Parasound P7 preamp which is totally analog. The only decoder I use is the Involve.
 

Lance7489

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That is a form of pumping. Do the input channel swap and see what happens
Just thought of something. Could the input level affect this ? On the V2, I always leave the input level at center. I'll try turning it down & see if that does anything. On the original SM, there's no attenuation.
 

chucky3042

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Just thought of something. Could the input level affect this ? On the V2, I always leave the input level at center. I'll try turning it down & see if that does anything. On the original SM, there's no attenuation.
Best to keep the input level as HIGH as possible, set just before the point of clipping (as noted by the RED LED on top of the LEVEL knob. Adjust the output knobs down as need be.
 

chucky3042

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Switched cables, CD players, even sound systems. Also, same thing is happening with 2 different surround masters. I originally thought it might be a bad cable or a bad RCA jack, but no such luck.
On switching the cables did the pump swap sides?
 

MidiMagic

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More thoughts:

- Could there be something wrong with a speaker?

- Is there some resonant object in the area affected by the sound?

- My ears do something like that at a very low sound level. Could this be the case?
 

Lance7489

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More thoughts:

- Could there be something wrong with a speaker?

- Is there some resonant object in the area affected by the sound?

- My ears do something like that at a very low sound level. Could this be the case?
No. I have 2 different systems & 2 different surround masters. It happens on both systems.
 
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