INVOLVE SQ - IS HERE

[wappinghigh]

Can someone please sum up the issue of the sales suspension for a newbie to this thread? Thanks

 

[rustyandi]

First I do not have SQ MaCarther park I thought I had it
I have it in QS or CD4
But I set up my system again using the
Project 3 QS and SQ test records
and then The Quadrafile SQ test
I played the tracks on both Project 3 LPs
I found the channel separation excellent
with both systems
But with my system I have some controls
on my table there is a front/back volume
knob that I am not sure that 12 o'clock
is dead centre I have it at 11 o'clock for QS
and 1 O'clock for SQ

Ron

 

[chucky3042]

Hi Wappinghigh

I hope this suspension will only be a few days while we tripple check that every thing is OK and we have answers to all 3 customer issues. So fear not all orders will be honored- just slight delay.

I thank Ron for his report - first bit of good news (I think).

Will know more tomorrow.

Regards

chucky

Can someone please sum up the issue of the sales suspension for a newbie to this thread? Thanks

 

[Yucca]

Just an add from a totally non experimented surround listener (only listen in DPLII ot Trifield from stereo before) : the sound is very good to my ears and "seems" like discrete sources for me (fantastic on 70's material like Zappa or Supertramp), but the front speakers output levels are very very low. Found this odd first, but I just turned down the rear levels and recalibrated my Sub to get a right balance. it's balanced now, but don't know also if normal...

(only Involve mode, 4.1, no SQ for me)

 

[wappinghigh]

Thanks Chucky..

I've tried to source a Zektor MAS 7.1 analog switch so I can try something like your processor with my Music files..

At the moment I run an Exasound 5.1 analog out DAC straight into power amps..

Can you do the same with the Involve?

Cheers

 

[KevinD9052]

I've been listening to my SQ-Surround Master for 6 months now and I'm loving it. The QS is perfect and the SQ is nearly so. Someone here mentioned decoding is between the SQ-W & the Tate. That's pretty damned good in my book! The separation may be a tad less than a Tate. But decoder action is totally transparent. The intended mix-good or bad- comes through. Is it discrete? No, it never will be. I sometimes think the Tates are too aggressive with separation & we may be expecting that from the Surround Master. I don't know why some of us are having problems. And I feel for you guys. QC? Poor balancing? Don't know but I'm sure the guys at Involve will get to the bottom of this for you ASAP. Hang in there. It is a good box!

 

[Yucca]

I think a good part of the problem, for me and only in Involve mode (no SQ) is the balance between rear and front, if you have different speakers.
If too loud rear, you only hear behind and it's not natural at all
If too loud front, the final effect seems to be only like a kind of Ambisonic from stereo, with some ambient infos rear.
When you find the right balance between front/rear and speakers positioning (I had also to change a little, because can't modify delays), it's magic. But you have a small work to do before, not so easy...

 

[chucky3042]

Hi Again

I am indeed old and stupid - could you detail this a bit more as I do not understand the question.

regards

Chucky

Thanks Chucky..

I've tried to source a Zektor MAS 7.1 analog switch so I can try something like your processor with my Music files..

At the moment I run an Exasound 5.1 analog out DAC straight into power amps..

Can you do the same with the Involve?

Cheers

 

[wappinghigh]

Well at the moment, I play all my multichannel tracks direct from a computer via an Exasound e28 multichannel DAC out via 5.1 analog out to power amps. The DAC controls volume.

So the DAC is attached via analog out into a bank of power amps. No pre.

If i buy an Involve to process stereo tracks, then this will also feed 5.1 analog out. Right?

So either I pull and swap the analog cable : which is a PITA, or I get a switch.

When the Involve is connected straight to power amps this way, how do I control volume? Or do I do this at the original stereo source?

 

[wappinghigh]

Think of this as connecting 2 SACD players out via 5.1 into the one set of power amps.. with the SACD players individually controlling volume..

 

[chucky3042]

Hi Again Kevin and Yucca

I value your observations and actually agree with them. We deliberately slightly reduced some aspects of separation of the SQ unit to around 30 dB to reduce pumping and other artifacts. See Overtures post:

https://www.quadraphonicquad.com/forums/showthread.php?17525-INVOLVE-SQ-IS-COMING/page7

I am really worried that we may have had a QC problem or the units to the 3 customers were somehow defective. The truth will come out in a few days time hopefully.

Regards

Chucky

 

[chucky3042]

Hi wappinghigh

Yes if you direct feed your power amp from the SM then you must control the volume from the CD player or say a pre amp prior to the SM.

Regards

Chucky

Well at the moment, I play all my multichannel tracks direct from a computer via an Exasound e28 multichannel DAC out via 5.1 analog out to power amps. The DAC controls volume.

So the DAC is attached via analog out into a bank of power amps. No pre.

If i buy an Involve to process stereo tracks, then this will also feed 5.1 analog out. Right?

So either I pull and swap the analog cable : which is a PITA, or I get a switch.

When the Involve is connected straight to power amps this way, how do I control volume? Or do I do this at the original stereo source?

 

[alaric smith]

Hi Chucky,

Do you think that this might be a batch problem? - Sorry, might be pre-empting things. I have plugged mine in but haven't run anything through it yet. I will give it a go this afternoon and give you some feed back.

Hopefully, it is just a set up problem.

Alaric.

 

[chucky3042]

I do not even know if there is a problem or is it our end or the customers end. We will be systematic.

Regards

Chucky

Hi Chucky,

Do you think that this might be a batch problem? - Sorry, might be pre-empting things. I have plugged mine in but haven't run anything through it yet. I will give it a go this afternoon and give you some feed back.

Hopefully, it is just a set up problem.

Alaric.

 

[Yucca]

Hi Again Kevin and Yucca

I value your observations and actually agree with them. We deliberately slightly reduced some aspects of separation of the SQ unit to around 30 dB to reduce pumping and other artifacts. See Overtures post:

https://www.quadraphonicquad.com/forums/showthread.php?17525-INVOLVE-SQ-IS-COMING/page7

...

Regards

Chucky

Great, I didn't read it !

Is there a general directive we could follow to refine levels on rear speakers ? i.e. when you have a pink noise at 75dB for the front, should we get also 75dB for rears or less ?
Same level for rears is for me wayyyy to high, so I've adjusted levels with my ears only. It's finally very good, but approximative, and maybe a general rule would be good for beginners...especially also when you don't have same speakers front/rear.

 

[ss9001]

I do not even know if there is a problem or is it our end or the customers end. We will be systematic.

Regards

Chucky

I have some data for you. I started measuring using both the front & rear tape inputs on the Sansui & just switched out the left/right but that could introduce differences based on the front/rear inputs. Also, I was measuring my front speakers vs rear speakers and even though they are all Magnepans, they are not the same speakers. The fronts are Maggie 3.6's and the surrounds are Magnepan MCMG1's (a whole lot smaller width, wall mounted panels & not as tall). You can look up the specs at Magnepan's web site.

I got the point of confusion trying to do Test 2, took a break and tackled it again using only 1 tape input on the Sansui.

terminology: L = left, R = right,
Fr = front, Rr = rear

1Khz mono signal (also did one test with 500 Hz) from Sony XA-9000ES SACD/CD player directly to Surround Master. I took Surround Master inputs OUT of the Sansui tape loop "REC" outs to eliminate that variable.

Sansui receiver has VU meters so I'll provide those.

Caveat - I have dipolar planar Magnepan speakers with panel "drivers" across the horizontal so trying to measure them is imprecise at best, the meter varies a lot sweeping across the panel from outside ribbon tweeter, past a wooden break, to the gridded mylar midrange/bass panels. Due to being 1Khz, I started at one edge of the ribbon section then just past the wooden piece to the mylar part. Crossover between the ribbon & midrange part of the mylar being a factor.

Test 1 using my original way of using both Fr & Rr tape inputs to show Fr/Rr volume difference:

using Sansui's volume control, adjusted Sansui VU meters so that it read ~10 watts front which gave between < 1 w rear, I estimate slightly > 0.5 w. the differences between hash marks aren't linear of course. I have the log calc for watts vs db but take this for what it is, an imprecise estimate based on the hash mark. this is at dead center Fr/Rr balance and take into consideration that the rear speakers are bass limited compared to fronts so thinner sounding. That shouldn't impact a 1Khz signal, tho. This is using the Involve setting, not bypassed turned off.

approx 83-84 dB front speakers, about 6" from ea speaker
approx 64-65 dB rear speakers, about 6" from ea speaker

call the difference ~ 18-20 dB

Test 2 is where it got confusing and I ended up doing it differently. These are the results from using only the Front Left Tape Loop Input as the input into the Sansui. Also note, I can only approx the lower VU reading; it was a "smidge" higher than 0.5 dB but at least it's consistent. All speaker measurements taken from the Left Front Speaker due to using only the left front Sansui tape input as input for all SM outputs:

CD Left to SM Left, CD Left only. Left out from SM to receiver LFr tape in.

85-88 LFr out, 10 w VU
85-88 LRr out, 10 w VU

for Fr/Rr crosstalk,

64-72 RFr out, 0.6 w VU
66-74 RRr out, 0.6 w VU

CD Right to SM Right, CD Right only. Right out from SM to receiver LFr tape in

85-90 RFr out, 10 w VU
83-89 RRr out, 10 w VU

For Fr/Rr crosstalk,

67-75 LFr out, 0.6 w VU
66-75 LRr out, 0.6 w VU

I can post my initial way for testing later, if you would like, but I'd probably re-do them since I got confused at one pt what I was doing!

one interesting side-comment, while doing it so that I checked the rear speakers from the Rear tape outs, I found the 500 Hz signal was bleeding a lot more (audibly & measureable higher volume) than the 1 Khz signal.

Considering the imprecision in measuring panel speakers and the variance in dB level when sweeping across about 1/3 of the panel, I don't know how much significance to attach to this observation:

the right signal from the SM seems to look 1-2 dB louder, especially the peak from the SM front right output (2 dB). this could be well within tolerances considering imprecise measurements but this could also help to explain the shift in the trumpet on that P3 QS LP from front center (Sansui) to somewhat right of center (Involve) and also how the one horn seemed to be attentuated by Involve. it also may help to explain a subjective lower rear volume than Sansui QS due to how the decoder is working on shifted balance. I'm not an EE (I do have Chem E deg from long ago ) so won't presume to know. Still, if one can believe the 1-2 dB diff is real & not a measurement issue, that could be causing some very minor shift in how the Involve part of the decoder is working on real music. software is the same from unit to unit so I wouldn't think it's that.

Does the above tell you what you want to know?

And do you want the results from measuring the rear speakers when using both front & rear tape inputs? If so, I'll have to sort them out. Considering the time difference & me traveling this week, if you want them, I can certainly try to post later today.

I'll be honest, based on my original way, I was ready to conclude my unit was right centric but that could also be some variances in the Sansui inputs so I decided to start over & follow your suggestion to use only a 1 input. And the measurements seemed more consistent, I was getting confused the way I started out.

I would think the real proof would be actual voltage measurements at the outputs with same input voltage & freq. but I'm not in a position to do those today as my multimeter is dead & never replaced. but if my measurements look OK or reasonable, let me know.

Chuck, I've spent ~ 4-5 hrs on this today & have to put my setup & cabinets back to normal, and I don't know if duplicating this with some SQ LP in SQ mode is going to help but if you think it will, I could try to tackle but 1) I don't have a test tone SQ LP and 2) it will have to wait until next weekend.

 

[Robert van Diggele]

Great, I didn't read it !

Is there a general directive we could follow to refine levels on rear speakers ? i.e. when you have a pink noise at 75dB for the front, should we get also 75dB for rears or less ?
Same level for rears is for me wayyyy to high, so I've adjusted levels with my ears only. It's finally very good, but approximative, and maybe a general rule would be good for beginners...especially also when you don't have same speakers front/rear.

When setting up your system and the levels, it is recommended to get the same level on all speakers, measured from the listening position. 75dB is the standard, although I caalibrated my system on 70dB, as my sound level meter has 10dB intervals starting at 60dB.

Of course this does not mean that you always have to listen to music at 75dB. For me that is way too loud as well, 60dB is loud enough.

In my system, this is done with 5 identical speakers, so I cannot give any advice to people who have different front and rear speakers. Only advice, get matching set of speakers

 

[ss9001]

when you have a pink noise at 75dB for the front, should we get also 75dB for rears or less ?

good question, and if I remember the theory behind matrix decoding (old Scheiber sphere ideas), front to rear separation depends on phase differences between L-R difference signals. IF my aged memory isn't fooling me & I have it right, a monophonic sound dead center in the front (pink noise or single hz) shouldn't transcode to the rear or at least minimal bleed. mono signal results in L-R = 0, no amount of phase shifts by the matrix decoder should put much in the rear. some bleed is normal but I don't think you would get equal sounds from front to rear with a mono pink noise signal.

Chuck or Dave can correct me as needed, as this is all from memory from decades ago reading articles. Wendy Carlos' online website that Dave linked up to in an email to me weeks ago will give you the exact math for the algorithms as well as descriptions.

these are from her site:




you are correct that in general, front & rear, left & right output should be approx same when calibrating. but in the context of a modern home theater receiver with a room calibration system, the receiver sends the test chirps to each speaker one at a time and balances the preamp levels so they all put out close to same dB. that is not the same as the volumes in each corner derived from a matrix decoder. and the degree of front/rear & corner to corner separation depends to some degree on how far apart a L & R sound is at any given time. a hard left sound potentially could have more put to the left rear than a slightly left of center sound.

IIRC, that's why front left/right balance is important. if that's not "right" due to some imbalance, then the decoding action is altered and you won't get the same rear Lt/Rt separation & front/rear separation.

and that's why you still need a balance control in the setup

 

[QUADradial]

[video=youtube_share;33uryepyZi4]http://youtu.be/33uryepyZi4[/video]

Here is the best way that I can show the problem. Notice during the front vocal test how much deflection the Tate has in the front channels compared to the Involve. Because the front channels are so low, it makes the leakage in the rear channels much more noticeable.

 

[ss9001]

^^
Tab, what album is this from? if it's one I own, I'd like to try it. I have put my system back to the way it was so no more testing today. I can hook it back up next weekend.