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Sound engineer's monitoring and HiFi + HT system with active Yamaha NS-1000x, multi-subs and FIR QSys processor in a particular and treated room

Igor Kirkwood

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Jan 28, 2020
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I am Igor Kirkwood, a French sound engineer, recording classical music with minimalistic techniques, natural acoustics, high quality microphones (mostly Neumann TLM 50), no DSP process in recording and mixing. I have also worked for the french hifi magazine DIAPASON, mainly reviewing loudspeakers.
A 10 years strong partnership with Jean-Luc Ohl for technical setup, programming and measurements, helped me to install an uncommon high-end monitoring system.

Some of my recordings

* Arvo Part, Deer's Cry, ECM records


* Music of "Ridicule", a movie of Patrice Leconte on DECCA label, recorded in 5.1 with a DECCA tree.

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*The well known CHRISTUS REX soloist Herve Lamy, Jade/Universal

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*Bach’ s integral DDD of the organist André Isoir, edited by CALLIOPE, re-edited by LA DOLCE VOLTA

*Bartok, Music for piano strings percussion and celesta, with the Saint Petersburg Orchestra, CALLIOPE

Audio system

For my work (editing and mastering) but also for my pleasure, I need a very high quality audio system : neutral, powerful and versatile.
Jean-Luc Ohl, a talented engineer (from company 44.1) did the setup, QSC programming and all measurements analysis.

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The listening room is about 6m x 5m x 4m (120 cubic meters), high ceilings (3 m to 5.4 m), with few parallel walls, well treated with 2 to 10 cm rockwool on most walls (total of 4 cubic meters absorbing material). Measured reverberation time RT60 is 0.2s at 500 Hz and because the room is located in a very quiet place with no street nearby, its residual noise is low, 15.5 dB measured with NTI XL2 and class 1 microphone..

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Audio system details
  • 2 front active Yamaha NS 1000x with tweeters replaced by FOCAL Beryllium
  • 2 surround passive Yamaha NS 1000x
  • Central soundbar with 5 coaxial Kef Q900, center loudspeaker for treble and mid, near left and right for center bass (85 to 300 Hz), far left and right are unused for the time being
  • Multi-subs with 4 active subwoofers SVS PC2000 cylindrical 350 Watts
  • QSC QSys Core 110f processor, 8 inputs and 16 outputs configured for routing, FIR crossovers, 8192 taps FIR EQ and parametric EQ
  • total of 14 channels of class-D amplifiers from Rotel, Crown and Hypex
  • UHD players Sony 700 and Panasonic UB 9000
  • TV screen: LG OLED 8k 88 inches
Schematics

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1/ In-room MMM measurement without subs and without equalization, measured thanks to loudspeakers.audio method, score=7.3

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2/ Same MMM measurement with multi-subs and with FIR equalization score=8.8

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After this quick presentation, I’ll add technical details soon and explain some choices.
 
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Wonderful entry into Audio Science review. :D I like everything except the components being so close to the floor... Lol.. I am the same obsessive way in the kitchen in that I don't use the lower cupboards and they are all empty. :D How did you manage the switch to the new Be tweeters? Was it a direct fit or require some adjustments?
 
Clearly a labor of love, and I hope you enjoy the hell out of it!
 
So, it's more home hi-fi system or it's also used for monitoring duties also?
If it's a home solution, how do you compare it with another studio audio systems available for you?
Beryllium mids and highs are not the thing that easy to find.

And while it looks like good "not-super-expensive-from-hiend-POV" scheme, it have at least one flaw: most probably, one will need a specialist qualified like Jean-Luc Ohl to achieve such results...
 
Wonderful entry into Audio Science review. :D I like everything except the components being so close to the floor... Lol.. I am the same obsessive way in the kitchen in that I don't use the lower cupboards and they are all empty. :D How did you manage the switch to the new Be tweeters? Was it a direct fit or require some adjustments?
The Yamaha Be tweeter is certainly the weak point of NS 1000x.
Original crossover of this tweeter is 6000 Hz which is too high to keep a coherent directivity.
The Focal beryllium tweeter is much better and can be crossed at 1800 Hz with the QSC FIR processor using a high slope filter at 80 dB by octave.
Note the very light correction comparing response without correction and response with FIR linear phase correction.

To insert a FOCAL Beryllium tweeter on a Yamaha NS 1000x loudspeaker, you must design a special base.

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Hello @Igor,

I thank you very much for your recent kind visit again to my project thread of multichannel multi-driver multi-amplifier fully active stereo project where I have been using Yamaha NS-1000 (not NS-1000M nor NS-1000x) + Yamaha YST-SW1000 (L&R subwoofer) + Fostex T925A (super-tweeter) with OKTO DAC8PRO (8-Ch balanced XLR-out DAC) and DSP EKIO (as system-wide XO/EQ/time-alignment center); as you well aware, I now use four HiFi integrated amplifiers directly (eliminating LC-network and attenuators) and dedicatedly driving woofers, Be-mid-ranges, Be-tweeters, super-tweeters. (My L&R YST-SW1000 subwoofers have own powerful amplifier in them.)

You would please find my latest system setup here on my project thread.

It is my great pleasure knowing your new wonderful thread here in ASR Forum; you are fully utilizing Yamaha NS-1000x and other gears in fully active configurations. Now I learned that you are also using an additional pair of NS-1000x in passive mode as surround (rear or side?) supplemental speakers. I am very happy noticing we are in the the same league of loving the-still-amazingly-wonderful Yamaha NS-1000, NS-1000M, NS-1000x and NS-2000.

In this my first post on this thread, let me first inquire you about your selections/choices of the amplifiers; you use CROWN CT8150 for center SP array (consists of five KEF Q900) and ROTEL RMB1077 (7x130 Watts) blade-type multi-amplifier for fully active front NS-1000x.

At least in my project using NS-1000, I went through rather intensive amplifier exploration, and finally selected four different HiFi "integrated" amplifiers directly and dedicatedly driving the SP units/drivers. As you may agree, generally speaking, we do not need powerful amplifiers to drive tweeters and super tweeters; as I shared here, even Greg Timbers uses "reasonable and budget" Pioneer Elite A-20 for compression drivers (super tweeters) in his extraordinary expensive multichannel stereo system with JBL Everest DD67000 which he himself designed and developed.

Furthermore, through my intensive amplifier exploration, in my (our) multichannel fully active setup I found I could subjectively hear/distinguish rather subtle "sound characteristics/inferiority (especially S/N and sound cleanliness) between the tested amplifiers. Just for example, I first intensively compared Yamaha MX-A5200 (Class-AB) 11-Ch AV amplifier (all in balanced XLR connections) with my reference ACCUPHASE E-460, and found as follows;

1. I could reconfirm the superiority (compared to MX-A5200), in all aspects of Sound Quality, of my Reference Sound system mainly thanks to the very nice ACCUPHASE E460, and also thanks to the fully renovated LC-network, still excellent YAMAHA-NS1000's WO, SQ and TW, together with SW YST-SW1000 and ST FOSTEX T925A.

2. I should be very much careful enough in deciding the possible multichannel amplifier(s) in my project. The total Sound Quality and power of such multichannel amplifier(s) should be about the same or superior to ACCUPHASE E-460
(in passive single amp configuration).


(As for the details and spec of MX-A5200, please refer to here, here and here.)

That was actually the start of my long and intensive amplifier exploration in my multichannel multi-driver multi-amplifier fully active project with NS-1000. I believe, and I assume you too believe so , that our multichannel multi-amplifier active setup wound be highly sensitive in subjective listening sensations/differences of each amplifier's sound quality and characteristics (or sound colors).

It would be also rather unique in my setup that I use HiFi "integrated" amplifiers; you would please find the reasons and rationales, at least in my case, here, here and here.

I would highly appreciate if I could hear your general thoughts on amplifier selections in your setup and mine.

Edit to add: on 21:12 PM March 3 Japan time
I also intensively evaluated/compared ROTEL RB-1582 MkII (Class-AB, balanced input) with ACCUPHASE E-460 and BENCHMARK AHB2 (please refer to here, here and here); again we (my wife + my audio enthu friend + myself) could subjectively hear/identify the sound characteristics (color) of the three amps in my passive and active setup using Yamaha NS-1000.
 
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The Yamaha Be tweeter is certainly the weak point of NS 1000x.

I partly agree with you, and I take a different approach compare to yours; I simultaneousdly use fairly nice metal horn super-tweeter FOSTEX T925A to compensate Yamaha Be-dome-tweeter JA-0513.

In my latest setup, Yamaha Be-tweeter JA-0513 sings over 6 kHz ( high-pass LR filter of - 12 dB/Oct at 6 kHz) and FOSTEX T925A sings together over 8.8 kHz; the relative gains for JA-0513 and T925A can be flexibly controlled by the dedicated "integrated" amplifiers since the efficiency of T925A (108 dB/W at 1 m) is much higher than JA-0513 (93 dB/W at 1 m). Please refer to my post here for the details. As you know well, JA-0513 clearly drops over 14 kHz, while T925A is flat up to around 40 kHz. (I always have low-pass [high-cut] - 48 dB/Oct LR filter at 25 kHz in DSP EKIO, though.)

You would also please note the very unique physical alignment/positioning of T925A (singing together with JA-0513) in my setup as shared in my post here and here.

Having the 0.1 msec precision time alignment established all over the SP drivers (as well as between L-SPs and R-SPs) at the listening position, the unique up and down far separated Be-tweeter JA-0513 and FOSTEX T925A super-tweeter give wonderful pseud-coaxial-feeling sound stage with amazingly excellent "complete disappearance" of SPs.
 
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I would highly appreciate if I could hear your general thoughts on amplifier selections in your setup and mine.
I took part to most technical choices in Igor's system. On the amplifier side, the Rotel and Hypex were allready used. I choose the Crown because of its 1U compacity for 8 channels and no cooling fans, so no noise. Its sound was no real criteria because for me, all correct amplifiers sound the same.
I sometimes compared amplifiers with my ABX comparator from QSC : unless overload, channel imbalance, noise or design defaults, there is no reason for amplifiers to sound different. I would be surprised to find amplifiers with no measured defauts that are audibly distinguable on ABX test, but if someone gives us amplifier models that sound different, I'd be happy to test with other listeners and share.
 
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I took part to most technical choices in Igor's system. On the amplifier side, the Rotel and Hypex were allready used. I choose the Crown because of its 1U compacity for 8 channels and no cooling fans, so no noise. Its sound was no real criteria because for me, all correct amplifiers sound the same.
I sometimes compared amplifiers with my ABX comparator from QSC : unless overload, channel imbalance, noise or design defaults, there is no reason for amplifiers to sound different. I would be surprised to find amplifiers with no measured defauts that are audibly distinguable on ABX test, but if someone gives us amplifier models that sound different, I'd be happy to test with other listeners and share.

OK, now I well understand the "historical sequences" of Igor's system.

Just for your possible interest, you would please find here (provisional) summary of my long and intensive amplifier exploration in my project.
You would please also find here and here the hyperlink index for my project.

I am always very much respectful for other people's multichannel active (DSP or analog XO/EQ) systems which have their own historical sequences and construction "policies"!
 
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hi @Igor Kirkwood thank you for posting details of your system. Can you tell me more about the choice of QSC core 110f in your system?
Why did you choose it - are there any particular killer features? What were the other options/competitors for multichannel DSP?

Some of the folks are not a fan of its analog performance - see thread about its sister product here, but the core 110f is specced similarly https://www.audiosciencereview.com/...s/qsc-q-sys-for-loudspeaker-management.29063/ and https://www.qsc.com/resource-files/productresources/dn/dsp_cores/core_110f/q_dn_core_110f_specs.pdf
Have you been able to notice any issues, or has the performance of the DSP exceeded any potential analog imperfections?

Thank you !
 
Real question is what's or how much in convolution kernel (8192 taps FIR EQ).
Great room and system by all means.
 
hi @Igor Kirkwood Can you tell me more about the choice of QSC core 110f in your system?
Why did you choose it - are there any particular killer features? What were the other options/competitors for multichannel DSP?
The QSC Core110f was chosen because of three main features : number of outputs, totally configurable schematics and possibility to import custom FIR filters (ie 2x8192 taps).
There are not so many processors that can be used :
- Yamaha DME24/64 have no FIR filters and user interface is a bit limited
- Xilica Solaro was not available at this time (it is limited to 4096 taps and you cannot instantaneously switch between FIR filters)
- Trinnov are not flexible enough, not cheap and you have to use their own correction software
- BSS Soundweb was expensive and also limited to 2x4096taps if I remember
- MiniDSP have a fixed layout and not enough outputs, moreover most can only be used with Dirac processing
- computer with native DSP processing was not an option
I agree that the QSys has not the highest specifications in terms of noise but in our case, it was tested to be inaudible.
This system is really driven by "objectivist" specifications : improve what you can really hear and forget specs on paper.
 
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@Igor Kirkwood and @jlo thank you for the details. I'm likely going to purchase this in a few months, so I have some more questions and would love to learn more from you.
Is the custom FIR filter limited to 8192 taps per filter? I believe audiolense (which Mitch barnett recommends for room correction) generates 65k tap filters by default. Is there any specified limit to how much it can process in terms of total filter taps, flops, or some other metric?
Is there any functionality to allow limiting the peak voltage at the output? (to protect a subwoofer driver from over excursion)
Is there any compressor functionality?

Would love to get a Trinnov, it has sufficient configurability for me, but well out of my budget. Hence trying to DIY with different components :)
Thank you !
 
The link to Loudspeaker Audio:


this measurement and room correction method completely changed my system… Highly recommended!

Dominique
 
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Is the custom FIR filter limited to 8192 taps per filter? I believe audiolense (which Mitch barnett recommends for room correction) generates 65k tap filters by default. Is there any specified limit to how much it can process in terms of total filter taps, flops, or some other metric? Is there any functionality to allow limiting the peak voltage at the output? (to protect a subwoofer driver from over excursion) Is there any compressor functionality?
The Qsys is limited to 8192 taps and you can only do 2x8192taps. I think that more taps is not allways wise : it may give you a better precision in lower frequencies but the calculated correction will then be wrong when temperature/humidity/opened doors, etc... change.
There are many ways in the QSys to limit output levels : limiters, compressors, rms limiting, etc...

To give an idea of what you can do with QSys, hereunder is Igor's schematics. Mainly due to custom FIRs, this takes 95% of QSys processing power (the Core110 is the smaller model of the range).

qsys-syno3.jpg
 
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wow @jlo this is such a big setup, thank you for sharing. I also read through qsys designer manual which gives me a much better idea of what is possible.
 
Hello @jlo and @Igor,

Thank you for your sharing the signal paths in Igor's setup which looks big intensive and really complex; I (we) need very careful look on it for understanding what's going on and what you can do with the QSys configurations! I fell it would be almost impossible for me to fully understand it by the single diagram you shared, though; I will further try to "read" the diagram.

Recently someone told me that my 5-Way 10-Ch multichannel setup with NS-1000 + YST-SW1000 + Fostex T925A makes him dizzy just try to decipher; your signal path in your big system using two pairs of NS-1000x + five front SP array + four subs, however, looks much much more complex/complicated to understand (at least for me).;)

It would be really amazing that you do it in full/complete clock synchronization. You definitely have no micro drift of synchronization (i.e. time dependent micro asynchronization) all over the so many channels SP drivers, right?

Please let me also ask you about how you could establish and objectively measured/confirmed the complete time alignment at your listening position (hopefully in 0.1 msec precision over 20 Hz to 22.05 kHz) for all over the multiple SP drivers...
 
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