Computer Optimization of Room Low Frequency Response

Great article Amir.

Having done all my active crossover and speaker EQ (sub + woofers), using ETF and REW measurements plus my hand-picked adjustments, I fully agree it's beyond mere mortals to get it perfect, especially across multiple room locations.

Do you know if Harman will release SFM/ARCOS for systems other than the SDEC boxes?

Since I have a Harman product, the DBX DriveRack 4800 and use System Architect, I'd hope SFM /ARCOS might be a purchasable plug-in for the SA suite.

amirm said:

Thanks Jonathan. I have not heard of any plans for them to release the software separately.

If you are willing to buy the new Revel subs, there is a path there. Namely, the ARCOS measurement suite can be used to perform the optimizations in the article. Once there, you can manually enter them into the computer software for the new subs. The subs have cross over capability built in so you can route the signal through them and get these benefits.

Failing that, you can buy one of the countless cars which have Harman technology built into their audio system .

Click to expand...

Very interesting article Amir, but I failed to follow how you get the 305 million total possibilities.

It seems me that considering the audiophile selfish perspective - optimal bass at a single position - the number of combinations for a single seat problem is rather low - 4392. I am assuming 61 frequencies and 288 possible values for subwoofer settings. Am I missing any parameter?

For those interested in this subject, maybe you should wade through a painful video (equipment problems) at a SMWTMS meeting.

"Earl Geddes on Multiple Subwoofers in Rooms"
http://www.ustream.tv/recorded/28637776/highlight/319149

-- I failed in finding any misspellings (typos), yet; I think you did a very good job. :b

It is a great article indeed. Thank you for sharing here with us.
...We are always 'desperately thirsty' for advanced knowledge.
...And in particular on a subject as this one, which is of great interest to me.

amirm said:

I get 5,124 for your scenario: 61 frequencies, 7 delays, 3 levels, and 4 "Q" settings. As soon as one adds subs, this gets crazy because for each one, you have to multiply by 61 alone for all the frequencies it can have. In my scenario we also have 8 seats to compare and optimize across. So yes, if you boil it down to just one sub, at one seat, then it is a smaller set. But even at 5124, assuming it takes you 3 minutes to measure and change values manually, you get 3 * 5,124 = 15, 372 minutes or 256 hours if my math is right!

Click to expand...

Thanks! I see I missed the delay = 0 - it was hidden behind the (none)

amirm said:

Thanks Bob. It was one of the most fun articles to write since it is a topic not covered elsewhere.

BTW, you will definitely like the next one: it is a "deep dive" into the audio performance of AVRs/Processors in general, and HDMI in the specific. It has even more data and measurements than this one.

Here is a shot of my test bench to wet your appetite:

Click to expand...

---- I recognize all the components from that picture.

And yes, I would be extremely interested to read this one as well.

________________

BTW Amir, back in 2009, I believe, I started a thread over at AVS Forum;
on all the best Automatic (and Manual) Room Calibration and EQ systems.
Few smart members noticed it, and a bunch of other members were waiting to have the 'experts' or members/owners with vast experience sharing their knowledge in one or more of these systems.
Unfortunately it went nowhere.

Yes, I'm like Kal Rubinson (and others) on those things; the future improvement in our listening rooms, from multichannel surround sound (music and movies) & also high fidelity stereo sound.

________________

* Here at WBF, I thought of restarting it, from all what I know already on some of the very best systems (ARC, Audyssey MultEQ XT Pro, Room Perfect, YPAO, Advanced MCACC, Trinnov, TacT, SARS, REW, and others like JBL Synthesis, and more...), but I think the interest from the overall average's membership here is not up to it. ...Or at least from all these systems in only one thread.

Furthermore, in another audio forum, which I won't name, I tried to have all the pertinent information contained in one thread only; sort of a reference mega thread.
But there too I failed; most members from that forum were not taking me seriously, or they simply didn't want to expand their knowledge.

I've learned a few things over the years .... And I had to adapt with the mentality of each venue with their people (audio/video forums and their members).
It's not easy to go where you would love to go, and learn more from the pros. ...All in one thread only, from this very specific subject. It is just too complex as each system is quite different from the next.

Still though, it is nice to compare them all from one place; Parametric EQs, Graphic EQs, digital DSPs, FIR filters, IIR filters, Frequency, Time domain, Phase accuracy, 3D Remapping, Vertical & Horizontal sound planes, DSX with Width and Height channels, Dolby Atmos, 9.2-ch., 11.3-ch., etc., etc., etc.

...Computer Optimization .... in sound. ...That's the future that we live in now.