# Four SVS Sub Integration



## Digione (May 8, 2006)

Well, I finally finished my systems EQ and managed to integrate all four SVS subs using REW (2xPB12NSD & 2xSB2000) and the subs to my satellite speakers using REW and Audyssey XT32.

I thought that posting my final results and approach might be interesting to some readers. 

I could only get the required sub integration using REW. Audyssey XT32, in the various forms that I can support, would not provide the required level of sub integration.

This took an extraordinary amount of time and effort so I have attached a PDF of the high level overview for the entire process; it is 43 pages long.

The following graphs provide a quick overview of the final results:








17. Final Sub Response with only SMS EQ








18H. Final 7.1 Frequency Response with AVP A1 XT32 EQ








19. Final 7.1 Frequency Response with 40Hz Crossover








23. Final Left Plus Right With and Without Subs

PDF Dropbox Link:

https://www.dropbox.com/l/s/HvRIdhq70g16PGazo8I0kp

For those readers who do not trust file sharing web sites I have attached a zip of the PDF file.

View attachment Sub Sonics.pdf.zip


Hopefully you will find the information informative and I would like to hear opinions about my results; problem areas, possible improvements etc. If any of you can answer my question on page 42, I would be very grateful.

I realize that some of the graphs “suffered” a little in clarity when I inserted them into the document. If there are any that need to be posted directly to this thread please let me know.

If you are interested, there is a lot more information and pictures regarding the room design, construction and early tests if you follow this link to my original thread on the AVS Forum:

http://www.avsforum.com/forum/19-dedicated-theater-design-construction/1465163-my-v-room.html

Paul


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## AudiocRaver (Jun 6, 2012)

At a glance, you have gotten excellent results, frequency response wise.

How are the soundstage and imaging?


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## Digione (May 8, 2006)

AudiocRaver said:


> At a glance, you have gotten excellent results, frequency response wise.
> 
> How are the soundstage and imaging?


While the overall frequency response is quite flat I was really aiming to get the subs integrated with each other and the satellites, minimize the LF decay times and obtain a good IR alignment. I have found that if any of these issues are "poor" it really affects bass "quality". 

The imaging is very precise and stable while the depth of image is also good often feeling as if some instruments are actually behind the front wall. The soundstage is evenly spread between the front speakers with no apparent holes, but it is very dependent upon the mix. It is also quite common for the sound stage to appear to extend out either side of the front side walls and the speakers virtually just disappear.


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## Talley (Dec 8, 2010)

How are you able to get down to the 10s on 12s? How large is your room.


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## Talley (Dec 8, 2010)

Ok...

1. wow
2. skimmed through your PDF...
3. wow
4. you posses tons more info about REW and sub integration than I do
5. wow
6. ok 1800cuft sealed room in a room produces much desired results then converting a room in a home to this meaning you confirm my thoughts... I need a new house with dedicated purpose built room

also... wow. Keep up the good work and I want you to analyze my REW file.... better yet, can I just fly you in for a weekend? LOL. I'm adding a second sub soon and god I need to figure out how to get these things dialed in. Right now I just run ONE sweep of Dirac and call it good but I know if my lazy butt really went into your efforts then my gains would be dramatic


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## Talley (Dec 8, 2010)

Skimmed your AVS post and one final thought here.

did you at least bond your grounding to your main ground at SOME point? I understand you have a dedicated 100 amp feed and you did an isolated technical ground and a seperate safety ground but all of these should be bonded at a single point only at the main service entrance. I did mine at the ground rod in the ground.

I have my main ground rod for my house panel with a #2 wire between them. Then I have my second panel for my AV gear where the safety ground ties into the main panel but I have an isolated ground that goes down to the 3 ground rods I have installed and at those 3 rods I have a bond jumper to the main house ground rod.

all grounds have to have a common bond. Just checking to see if you do.


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## Digione (May 8, 2006)

You answered this question above, it is only 1800 cuft and totally sealed except for a 4" fresh air vent that is only active when the HVAC or air circulation system is on. Remember there are four subs and the two subs that go down to 10HZ are corner loaded SB2000's.

SPL's in excess of about 95dB at 10Hz and below produce significant distortion, up to 50%. Above 15Hz I can support over 100dB with distortions down into the single digits.

However at frequencies this low all I do is feel the air pressure on me change and/or the room "flex", I do not really "hear" these frequencies even when running at high second and third order distortion.


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## Talley (Dec 8, 2010)

Digione said:


> You answered this question above, it is only 1800 cuft and totally sealed except for a 4" fresh air vent that is only active when the HVAC or air circulation system is on. Remember there are four subs and the two subs that go down to 10HZ are corner loaded SB2000's.
> 
> SPL's in excess of about 95dB at 10Hz and below produce significant distortion, up to 50%. Above 15Hz I can support over 100dB with distortions down into the single digits.
> 
> However at frequencies this low all I do is feel the air pressure on me change and/or the room "flex", I do not really "hear" these frequencies even when running at high second and third order distortion.


Good job none the less. Lots of hard work and dedication and seems to of been over several years worth too. Much kuddos! Merry Christmas to you also


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## Digione (May 8, 2006)

Talley said:


> Ok...
> 
> 1. wow
> 2. skimmed through your PDF...
> ...


Thanks for the wow, it was a lot of effort, most of it not much fun. 

I am no expert at this even though I used to earn my living building professional recording and radio studios and still work in the broadcast industry as a consulting engineer. I am happy to look at your .mdat file but staff like John M. are far better qualified than I to do that.

Always happy to help though if I can.


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## Digione (May 8, 2006)

Talley said:


> Skimmed your AVS post and one final thought here.
> 
> did you at least bond your grounding to your main ground at SOME point? I understand you have a dedicated 100 amp feed and you did an isolated technical ground and a seperate safety ground but all of these should be bonded at a single point only at the main service entrance. I did mine at the ground rod in the ground.
> 
> ...


All grounds/neutrals are bonded at the point of entry to the house ONLY. The 100 amp feed to the A/V room and the connectivity in the rack is then based upon a standard broadcast isolated technical grounding system. This ensures that beyond the point of entry, at no point is the neutral connected to the ground, this includes the new A/V panel and the equipment rack power distribution. All the grounds in the rack and the rack are then bonded to an isolated buss bar that is tied through an #8 copper wire to the A/V ground system. This ground point is not tied back to the house bonding point except via the ground connection in the 100 amp feeder.


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## Talley (Dec 8, 2010)

Digione said:


> All grounds/neutrals are bonded at the point of entry to the house ONLY. The 100 amp feed to the A/V room and the connectivity in the rack is then based upon a standard broadcast isolated technical grounding system. This ensures that beyond the point of entry, at no point is the neutral connected to the ground, this includes the new A/V panel and the equipment rack power distribution. All the grounds in the rack and the rack are then bonded to an isolated buss bar that is tied through an #8 copper wire to the A/V ground system. This ground point is not tied back to the house bonding point except via the ground connection in the 100 amp feeder.


Excellent!! Nice to see another person go as wacky as I did lol.


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## Digione (May 8, 2006)

Talley said:


> I'm adding a second sub soon and god I need to figure out how to get these things dialed in.


Adding a second sub or even more is not usually too much of a problem UNLESS they are different types or makes/models, like I tried to do. As you have probably read by now mixing sub types doesn't work very well


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## Digione (May 8, 2006)

Talley said:


> Excellent!! Nice to see another person go as wacky as I did lol.


People often under estimate the audible effects of poor power regulation and noisy grounds. 

Some of the grounding techniques we go to in Broadcast facilities and Data centers is exceptional in order to prevent switch mode power supply noise etc. and lightning strikes not getting into the signal and power chains. The only advantage these days is that digital audio and video has a vey high noise immunity. However that cannot be said of IT data infrastructures where I have seen noisy grounds cause data loss/corruption.


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## Talley (Dec 8, 2010)

Digione said:


> People often under estimate the audible effects of poor power regulation and noisy grounds.
> 
> Some of the grounding techniques we go to in Broadcast facilities and Data centers is exceptional in order to prevent switch mode power supply noise etc. and lightning strikes not getting into the signal and power chains. The only advantage these days is that digital audio and video has a vey high noise immunity. However that cannot be said of IT data infrastructures where I have seen noisy grounds cause data loss/corruption.


Likewise in the petrochemical industry where we do instrumentation we deal with shielding/grounding issues alot as well. When your dealing with a 4-20 milliamp signal operating at 24V your not talking much to induce voltage and cause false readings.


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## DqMcClain (Sep 16, 2015)

TANGENT: 
My dad used to work at JPL, and told me about the "Safe to Mate" procedure... where every single pin in a connector (2 or 3, up to literally hundreds depending on the connector) was tested against it's balanced mate, their common ground, the cable ground, and the chassis ground... then the test was signed by the technician that tested it. Then it was re-tested by another technician and signed again. Then the QA guy would have to verify that both sets of tests matched line-by-line, and sign it a third time. 

Then you could plug in the thing. And if you unplug it... you have to go through the whole mess again. It seriously takes 2 DAYS to plug in a cable at JPL. 

Kinda makes isolated grounds and service entry bonding seem like a day at the beach.


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## AudiocRaver (Jun 6, 2012)

I have read through your PDF of the "journey" you have undertaken. Here are a few FWIW-type observations:


You are to be commended for your patience and tenacity in endeavoring to persevere until you attained the results you were after, and documenting them clearly so others could learn from your experience. Bravo!
All that trouble? For bass? --- hold on, hold on, I jest, of course!!! = read the next observation...
I find it fascinating in the world of audio how priorities differ between listeners, even those with a lot of critical listening experience. My own interest - or shall we call it "preferred area of fanaticism" - is soundstage and imaging (SS&I). Even if I could have it demonstrated that I could hear the finer differences in bass performance that you have aspired to, I probably would never care to get there enough to put a fraction of the time into it. SS&I, on the other hand, I have chased well beyond the limits of patience or interest of most other listenrs I have demonstrated my results to. "To each his own" becomes "to each his own insanity" at some point.
Which brings us back to the first point. Great work and thank you for sharing in such depth. I cannot imagine trying to improve upon it. Except perhaps by making the move to Dirac Live.


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## AudiocRaver (Jun 6, 2012)

DqMcClain said:


> TANGENT:
> My dad used to work at JPL, and told me about the "Safe to Mate" procedure... where every single pin in a connector (2 or 3, up to literally hundreds depending on the connector) was tested against it's balanced mate, their common ground, the cable ground, and the chassis ground... then the test was signed by the technician that tested it. Then it was re-tested by another technician and signed again. Then the QA guy would have to verify that both sets of tests matched line-by-line, and sign it a third time.
> 
> Then you could plug in the thing. And if you unplug it... you have to go through the whole mess again. It seriously takes 2 DAYS to plug in a cable at JPL.
> ...


Yikes! But I guess if you're launching a mission to Mars.....


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## Talley (Dec 8, 2010)

AudiocRaver said:


> I have read through your PDF of the "journey" you have undertaken. Here are a few FWIW-type observations:
> 
> 
> You are to be commended for your patience and tenacity in endeavoring to persevere until you attained the results you were after, and documenting them clearly so others could learn from your experience. Bravo!
> ...


Haha.... Yup! Dirac for the win.


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## Digione (May 8, 2006)

DqMcClain said:


> TANGENT:
> 
> Kinda makes isolated grounds and service entry bonding seem like a day at the beach.


It sure does 

Much like trying to stop lightning strikes from getting into power and signal systems.


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## Digione (May 8, 2006)

AudiocRaver said:


> I have read through your PDF of the "journey" you have undertaken. Here are a few FWIW-type observations:
> 
> 
> You are to be commended for your patience and tenacity in endeavoring to persevere until you attained the results you were after, and documenting them clearly so others could learn from your experience. Bravo!
> ...


Thank you for your point of view. On this occasion it is was not a labor of love, just one of necessity.

I became a bass fanatic after many years of watching movies. I used to work in the recording industry and for all those years I only had a high end stereo system as my listening source. It was all about trying to listen to mixes at home on a system that sounded "similar" to what we had in our studios. Stereo imaging, depth and perspective were more important to me then, as bass was about as good as bottom E on a bass guitar or the "thump" of a well damped kick drum; so I understand your point of view. Many music fanatics I know are not interested in multi-channel sound and spend tens of thousands on their stereo exotica for exactly the same reason that you mention.

I suppose each to his or her own...viva la differance .

You are probably correct in that I am not too sure now if I can make any significant improvements, including DIRAC, that at my age I can hear. However my eyes are still good so I look forward to seeing 4K in my room when they finally release an affordable 4K DLP.


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## FargateOne (Mar 3, 2015)

I have read your paper just for the fun of it. I do not have your knowledge but I can appreciate your journey.
Thank for sharing it


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## Talley (Dec 8, 2010)

FargateOne said:


> I have read your paper just for the fun of it. I do not have your knowledge but I can appreciate your journey.
> Thank for sharing it


Same here.... ditto what he said.


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## Digione (May 8, 2006)

FargateOne said:


> I have read your paper just for the fun of it. I do not have your knowledge but I can appreciate your journey.
> Thank for sharing it





Talley said:


> Same here.... ditto what he said.


Not too sure it was that much fun .

Sorry if my attempt to document my "journey" was a little difficult to follow, it took almost a year to get all those tests done and documented. I tried to simplify and abbreviate things wherever possible and not get too technical by making as many generalizations as I could, without glossing over too many points. In doing so I omitted a lot of detailed and more accurate technical descriptions that I am sure would have helped readers better understand what I did, also I didn't have the time to write a "book". However, as I am sure you both realized, nothing is as easy as it seams and listening to those who have a lot more experience than yourself (Ed at SVS) can really make your life easier. Hopefully it was a worth while read .

I am happy to answer any questions or clarify anything that I have written.


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