Balanced Controversy - Revisited

I've been looking to upgrade an old (c. 1985) stereo Beosystem 5500-based system driving a pair of Bohlender-Graebener Radia 520s via a Carver TFM-22 amp and a custom-built 96l 12" sealed sub (Q around 0.6) to include 5.1 or 7.1 surround. The primary display device is a Sony 32" HDTV. (A pair of Carver Silver speakers requiring repairs to the ribbons sits in storage, as well).

So, naturally, I find Outlaw's offerings interesting.

I particularly liked the idea of retaining a good stereo amp for the L+R mains, and using M200 monoblocks for the other speakers (considering 2 or 4 Radia 420s and a Radia 220 center). Of course, then the question of speaker-level signals to the speakers or line-level signals to amps near the speakers comes up. And, if considering the latter, should I use balanced signal transmission? Soundhound's criticisms of balanced circuits throughout noted, I wonder if balanced input and output stages for a run of 65' (wiring distance to farthest speaker in a 25x16 room) are justified. 65 feet is starting to get up there, in terms if length.

Soundhound made it sound as if the preponderance of odd harmonic distortions in balanced designs, even when confined to I/O stages, render any such design not worth considering. If that were the case, then the noise-immunity afforded by using balanced lines on long component interconnects would be for naught, if only to have to suffer odd harmonic distortion. Clearly, it must be possible to manage such distortion in managed systems. The question is, then, does the 990 do it well enough on it's balanced interfaces?

Bluntly, is anyone actually using, or planning to use, the balanced outputs on a 990, or have reason to believe that Soundhound blew a legitimate issue out of the realm of audability when it comes to a $1000 component (IOW, if it mattered that much, the 990 wouldn't even be a contender.)

RSH, this is a sensitive issue for some (but not for me!)

I will take balanced over unbalanced anytime. Check out this article that explains the difference:

http://www.audioholics.com/techtips/audioprinciples/interconnects/Balancedvsunbalanced.php

I have Carver Tripath digital amps with balanced inputs and whatever I wind up with - Outlaw or Anthem - I will be using balanced interconnects. Why do so many high end manufacturers like Bryston and Theta, just to name a few, make such a big deal of it? There's got to be a reason and the article I posted the link to explains it fairly well.

BTW, I am an engineer working for Honeywell so I am not really trying to blow smoke up anyone's butt

I also plan on using the balanced out's for the sub (it has a balanced input option & for the LCR where I am using electronic crossovers with balanced in. My main reason is to cut down the ground hum a bit. I've had to twiddle power more than I like to remove hum and still have a little if I put my ear to the speaker. I'm hoping balanced will remove this last bit.

stabie, I am jealous! My SVS sub does not have an XLR input. I guess I am going to have to live with it.

I plan to use the balanced subwoofer output of the 990 for the unbalanced input of a sub (intend on buying the LFM-1 along with the 990). The reason is because the route to the sub location involves going up a wall through the attic and down another wall (my house is on a slab, ugh!). This will be 50+ feet. I'll use an XLR to RCA transformer to go from balanced to unbalanced for the last few feet. Hopefully, this will allow me to benefit from the added noise cancelling properties of using the balanced output.

This is assuming that both the balanced and unbalanced outputs are active simultaneously.

I will be using the Balanced output because I am looking at connecting the 990 to a FBD on the way to the sub amp. Which a lot of people use to deal with room modes, ie rattling heat ducts..

http://www.behringer.com/DSP1124P/index.cfm?lang=ENG

barnabas-My velodyne hgs-18 would make you very jealous. It rattles the room without even trying.

trikos, do you have a balanced input on the sub or are you going XLR - RCA to the sub? I have heard good things about the Behringer but don't have a lot of practical knowledge. I'll download the manual. Does it essentially do room EQ for the sub?

barnabas: I am well aware of the advantages of balanced interconnections and their ability to fight inductively and capacitively coupled interferance.

Such interconnections are usually not used on consumer gear because (a) interconnections are short (though 5.1 setups are making that less true), (b) they add expense. Nevertheless, their value in combating interferance is well known.

That said, soundhound's observations regarding a relative increase of odd order harmonic distortion bears investigating: if the benefits of balanced drive are not there (because of a short run), and there are greater relative disadvantages because of the nature of balanced output stages, it might not be worth it.

As for running a balanced output to an unbalanced input (via simple XLR to RCA), you may be defeating the purpose, as the termination could unbalance the circuit (depending on the output stage topology). Furthermore, IIRC, balanced signals are referenced to a higher level than unbalanced ones, so you might need some attenuation (this may be built into some XLR to RCA adapters).

I hadn't considered the value of a balanced run to a sub amp: induced 60 Hz rejection, though that makes some sense. My sub, using a Hypex HS200 amp, does not offer balanced inputs :-( I have found that a 30 foot run of decent interconnect cable connected to signal (and chassis) ground at both ends carrying a single-ended sugnal to my sub amp does not pick up audable 60 Hz interferance, though. I did have a ground loop problem at one point, but running the three grounded power cord from the sub amp through a GFCI, and lifting the ground from the GFCI worked. (This is much safer than simply lifting the safety ground as any current inbalance caused by a ground fault (i.e. through a body) will trip the GFCI.)

Given runs of up to 65 feet, I am definately biased in favour of running line level signals to amps located near speakers, rather than speaker level signals and dealing with resistive losses: the BG speakers present nominal 4 ohm loads. If I have to run line-level signals that long, I'd prefer driving a balanced line.

So, the question remains: how bad is the odd order harmonic distortion from the balanced output of the 990? Is it as bad as soundhound suggests? I am not entirely convinced that (a) it is significantly worse than the unbalanced output and (b) the reduction of even order harmonic distortion from balanced output stages somehow masks what is present less.

I don't deny that the odd harmonic distortion from a balanced output stage might be worse than from an unbalanced one. The questions are "Is it noticible?" in the context of the rest of the signal quality produced by a $1k component, and "Is it the lesser evil when considering a 65 foot signal run?"

As I already have a decent stereo amp for the L+R mains (though I am considering upgrading to a better one, with balanced as well as unbalanced inputs), and the run from the 990 to that amp and speakers is the shortest of all, it isn't an issue for the most critical speakers when listening to two channel music. So, some minimal inaudable distortion to the surround speakers might be tolerable, even if the signal is theoretically "worse" by some measure.

I suspect however, that the benefits offered by a better physical connector usually used for balanced interconnects over an RCA phono plug probably exceed any increased odd harmonic distortion.

BTW, I hear that someone is offering to mod M200s for balanced operation. Does anyone know if that's correct, and at what cost?

Barnabas:

I have one sub now which is based on Infinite Baffle design vented behind the screen. It is connects directly to a Behringer 1400 watt amp in bridged mono mode, which does have Balanced inputs on the amp. So with a 990 I would have Balance from the 990 --> FBD --> AMP.

See: http://www.behringer.com/EP1500/index.cfm?lang=ENG These run about $300 a unit and since I use rack mounting they are ideal.

I am thinking of adding an LFM1 if I get a 990 to the second LFE output and using the FBD to handle both.

The FDB is an awesome unit. It allows you to flatten your sub response for your room and also "notch out" frequencies that are problem areas, like windows, heat ducts, or areas that are boomy because of room modes. They sell for $99 online, which is way too cheap for a unit like this.

We don't all have a anechoic chamber in our houses..

You will need to setup a PC with a mic to measure your frequency response. Since I build my own speakers, I already had that stuff.

A really good reference site for FBD and Infinite Baffle subs can be found at: http://f20.parsimony.net/forum36475/index.htm

trikos, thanks for the info and link. Very informative. For $99, it may be my next add-on toy.

I met a fellow audiophile locally at an amp comparison and he had just installed his IB. Very impressive. A few rattles to police but after that gets squared away, it will be nice.

Can you recommend a mike for PC to do the set-up?

Thanks,

b

Barnabas,

The EMU-404 sound card is excellent to connect a mic to, and has 192bit sampling. Very quiet and flat. http://www.sonicstate.com/news/shownews.cfm?newsid=1766

Coupled to the Behringer EMC8000 measurement mic:
http://www.behringer.com/ECM8000/index.cfm?lang=ENG

Then add the True Audio RTA software and you are away to the races: http://www.trueaudio.com/rta_abt1.htm

By the way, these are all available for $99 bucks online.

hmm, maybe the 990 will come out for $99...

I appreciate the links! What about the on-line software that Behringer talks about in the FBD manual? I am assuming the RTA software is similar but better?

True RTA is one of many out there, SpectraPlus/RTA is more high end if you want to go crazy. The FBD one is limited.

I just found that True RTA was easy to use and had Mic Calibration built in for the EMC8000.

I have been using it to setup my new room (sold my other HT with the house) but got stuck cause I need a 990. No sense tweaking it till all the pieces are in place.

Don't know how much longer I can wait before pulling the trigger on something else..

I hate silent movies..

I hear you (no pun intended)! I sold off my Denon 3805 last week. I have 4 amps and my Denon 3910 waiting to be worked and speakers being built now. Still got a lot of stuff to do to the HT wall as well.

It's Anthem or Outlaw for me. Quite a delta in price! But the Outlaw is really too deep for my cabinet (I can fix that) and it could be obsolete within possibly 1 year depending on HDMI outcome. This is tough! There's always 5.1 analog outs.

Oh, one thing I forgot to mention. If you are using a mic like the EMC8000, you need to supply phantom power to it.

Good luck!

All this talk of tuning sub signals for the room looks interesting. I tuned my sub for my last house using test CDs and a cheap SPL meter, but just using the sub's bandwidth and cutoff controls. Somehow, I'd like to do better this time around

If anyone's interested, this is the sub I had designed and built, by Kyle Richardson, of Acoustic Visions. I am extremely satisfied with it, for the sub-$1000 (at the time) price.

trikos, thanks for the links . Question though how much was your RTA and where did you find it at . Thanks in advance .

E'pin Sen Ob,

Then add the True Audio RTA software and you are away to the races: http://www.trueaudio.com/rta_abt1.htm

and the price is free if you don't mind poor resolution. Otherwise its $99 bucks.

Trikos thanks for the intel. I have great eyes.

Why do you think I went to a 160" screen

Trikos, LOL . At least it's an excuse to upgrade .

Check out this free software for setting up the BFD:
http://homepage.ntlworld.com/john.mulcahy/roomeq/index.html

Dundas, thanks for the tip . Looks like it could be worth a try . Have you used it and if so to what success .

Dundas,

Yes, good info. I can do all these things without. But for people that don't have the equipment, this would be an excellent solution.

If it works..

Trikos, what do you mean by that?

Assid,

You need to supply 48v to the mic in the balanced mic supply.

You can buy some small pro mixer used from a pro audio store, or a new small pre-amp like http://www.behringer.com/MIC800/index.cfm?lang=ENG

or you can build one like Eric Wallin's at http://mysite.verizon.net/tammie_eric/audio/preamp2/preamp2.html

Even new, some of these mic supplies are like $50.

What about this model of theirs, that has a built in mic amplifier?

http://www.behringer.com/DSP110/index.cfm?lang=ENG

EDIT: Oh, after reading a little of the manual, I don't think it would work as we'd want to use it...

That unit is fine, but is based on the Feedback Destroyer, but not the Pro. It is missing some features and has some that can cause you a bit of headache. Like compressor/noise gate which is not for this application. Its $30 more than the FBD so I prefer to go with a $30 used mic mixer since the FBD will end up staying in your HT equipment.

The rest can be extracted to test other speakers or used in another room for building speakers. You don't want to put your FBD out of the loop every time you want to do some speaker testing.

Update: Also you will want to be able to download your FBD settings thru the MIDI port to a PC for a backup, and also to play with different group settings. The FBD is nice that way. You can use it to test other subs and easily go back to your base settings for your current HT setup.

It looks like they have a new model:
web page

I'm ignorant about microphones. Are there dynamic mics, condensor mics and ribbon mics? I guess what I'm asking is, since I'm not a musician and don't have a good microphone or know anything really about them, nor the terminology, what would I need to buy that wouldn't cost an arm and a leg to get this thing to do what I want (eliminate harmonics)?

EDIT: oh, I see you already provided a link to a microphone.

So then, if I were to buy that microphone, I would plug it into a microphone preamp, then run a cord from the preamp to the FDP? Can you point me to an online source to buy the cords? And, would all the connectors on these two cords be balanced 1/4" TRS connectors?

Another question: By using this FDP, would you be "doing" what is considered room EQ?

EDIT: I emailed Behringer a question, and they suggested what I would want is another product of theirs:
ULTRACURVE PRO DEQ2496

Assid,

The new unit is almost 3 times the money that the 1124 is and with it being used for ~100hz and down I think the sample rate of the 1124 is fine. Also, like the 990, its not available yet.. Besides, I always keep focused on more power and the extra cash could go into more watts!

As far as the Mic/Preamp goes its as follows:

1) Not any mic will do. It to has to have a very flat response curve or measurements will all be a lie. The EMC8000 is pretty flat to 20hz, and the calibration file that comes with RTA helps to make it more accurate. Unless you want to send it away for calibration, which will give you a very accurate data model which you can setup a really accurate calibration file for your mic only (unless you bump it or something, then send it away again..). Most people find the one in RTA sufficient.

2) Parts express or your local Music store will have XLR (Balanced) cables unless you are a cable freak. In which case you will need to spend at least $1000 bucks on a 3 ft cable..

3) You plug the Mic into the Preamp (or Mixer) with Phantom power, which in turn is plugged into a soundcard like the EMU440 I described above into the line input (not the mic input).

4)The FBD will be connected to the 990 sub out (LFE, XLR Balanced) output. The output of the FDB will be sent to whatever Subamp you have.

4) You will be displaying your frequency response on your PC using the RTA software as you adjust FBD to flatten and correct issues with your room for your Sub. (or any other speaker)

5) Your soundcard will be used to generate test tones, pink noise or a frequency sweep which is send into the 990 input and thru the FBD to the sub.

Since the FBD will have a perminent home between your 990 and the subamp, its a good idea to also connect the MIDI out of the FBD to your PC and suck out the settings into a file for safe keeping... Or use the software Dundas mentioned that has similar capabilities for the FBD, but I have not personally tried it yet.

Hope this helps..

Assid,

Of course the ULTRACURVE PRO DEQ2496 would be the suggested one, its 6 times the money. I vote for more watts instead!

ahhhh, I see. Thanks for the explanation. Very logical and easy to understand. If I can follow it, you know it's a good explanation. I appreciate your efforts to "edge-u-ma-cate" me.
I have a SB Audigy 2 ZS. Mine isn't the Platinum, so I'm not sure if I have a midi port on it...I'll have to read the manual. Also, what does a midi cord's connectors look like? Are they some kind of one-off connector?
The PITA I see is having to move my PC upstairs to my HT room...not so much the PC, but the 21" CRT monitor. Though, I guess I could hook the PC up to my RPTV. I have a laptop, but don't think the built in sound card is worth a crap. Although, I do think SB makes an external sound card for laptops...I'll have to read up.

Assid,

Caution on a lot of Sound Blaster cards. They are great for PC's and games etc, but most including the Audigy have some built in filters that can make sound measurements a head scratcher and also tend not to output at high enough levels as to not generate noise of there own. You need to pegging the volume control on your PC most of the time.

The EMU 440 is a "semi-pro" card which is designed for higher output levels (watts, or maybe watt) in the first place. Which means you have some headroom before entering the "darkside"

Audio card benchmark software like http://audio.rightmark.org/download.shtml will tell you that the EMU440 has way better signal to noise ratios than a Sound Blaster..

Most laptop soundcards will show up on the Right Mark Benchmark software as a snowstorm and can't output more than a few milliwatts..

JMHO..

Assid,

MIDI looks like the old style keyboard connector (dating myself here) which is about half inch around and has 5 pins on it. Almost all sound cards have either MIDI IN/OUT or a game port which you can buy and adapter cable to get MIDI IN/OUT on. There is also some USB to MIDI adapters out there, but I have no experience with them.

Thanks.
Hey, my keyboard still has that kind of adaptor. ..PS/2...at least I think that's the look you're refeering to.

Nope, trikos is talking about the old DIN adaptor, I believe - PS/2's predecessor.

You must be too young..

Re Home EQ Wizard
I have not used it to it yet to upload filters to BFD. Still waiting for one these to arrive:
http://www.audiotrak.net/xpmidi.htm

Have played with it some though and it works well and as advertised. Here is a discussion on a UK forum:
http://www.avforums.com/forums/showthread.php?t=203681&page=1&pp=15

The author of the program will respond to emails and he has also posted here:
http://www.hometheaterforum.com/htforum/showthread.php?s=&threadid=231473

I’ve only spent brief amount of time playing with this program but so far it’s amazing and it’s free! For BFD users it looks like its going to save them a lot of time setting it up.

Good info Dundas.

Most people can also just get a $19 Midi cable which can be had at most computer or music stores.

They look like this:
http://www.calibex.com/M-Audio-M-Audio--...ARE-PRICES-html

Also, if you pick up the EMU404 it has midi in/out built in. Since the Midi Mate is $50 and the Soundcard is $99, you get better signal to noise for another $50..

This is the only soundcard for a laptop, with a midi port, that I've found:
web page

Thoughts?

The sound card does not need to have a midi port. The laptop just needs to be able to communicate with the BFD’s midi interface.
http://homepage.ntlworld.com/john.mulcahy/roomeq/wizardhelp/help_en-GB/html/gettingstarted.html

I assume the RS232 to midi would be OK but I would email John Mulcahy to make sure.

Roger that on the midi port. I can just get a USB coonector for that.

The key for me is to be able to use my laptop, which doesn't have a real soundcard. So, I'd have to get a soundcard for it. This one seems promising....

This type II cardbus (Echo Indigo io) soundcard has a built in microphone preamp. Pretty cool.

Trikos, I thought earlier we were talking about using a microphone to do this with the FBD...now we're talking about using an SPL meter. Or is it just that one software program uses an SPL meter (Room EQ Wizard) while another program (True Audio RTA) uses a microphone? I think that's the case...
EDIT: I see now after reading TrueRTA's FAQ's. you can use just a SPL meter.
Which method would produce the best results with the FBD? Using a quality mic, such as Behrenger's own EMC 8000 and the TrueRTA software, or an SPL meter with the TrueRTA software?
Or, would it be by using that entirely free program, Room EQ Wizard and an SPL meter?
I guess the nice thing going with the TrueRTA, microphone, and the Indigo io PCMIA card is you would be equiped to do a lot more things, though more expensive in the end.

Either way, I'd still have to buy a sound card for my laptop, either PCMIA, USB or Firewire. And, I'd have to buy a SPL meter or a microphone. Oh, and the Behringer DSP1124P...and a USB to midi patch cord.
After buying all that, it wouldn't cost much more to just buy their Ultracurve . With that, you don't have to deal with using your PC, software, and patch cords. Though, you'd still need that microphone. It looks like it does a lot of other stuff too besides the DSP1124P functions, though I'm way too clueless at this point to know what else it could do for me. Perhaps someone with more than 2 functioning brain cells could elaborate on some of the other things you could do if one had that model? ?

Sorry for being a moron...
It's taking me awhile to grasp this...

Assid,

Setting up a solution with a mic/soundcard/rta is a "life time" solution to audio measurement. The alternate that Dundas came up with I see as more an one off FBD solution for say, tweaking your sub for your HT.

If you interests are in audio measurement for improving any speaker (or building them) than you need a good quality sound card (high signal/noise, etc) and at least 96khz sample rate to be able to properly sample 20khz signals. Plus a flat Mic, and software to generate and analyze signals.

Before picking up an external USB soundcard, do some research on who delivers the best "audiophile" solution at a resonable price. Also, sample rate is very important for higher frequencies.

If you just want to measure your sub, there is lots of solutions out there. I have heard some people have resonable luck with the Transit $99, but I have never used one: http://www.m-audio.com/products/en_us/Transit-main.html

The big difference between a SPL meter like the ones sold a Radio Shack and buy a quality measurement mic is the accuracy and sample rate you will be able to obtain with the mic solution. Some of the SPL meters do have a jack for connecting them to audio in, (I have one) but at lower freqencies are not that accurate.

Eric Wallin had done some work to try and improve the various Radio Shack SPL meters, but by the time you are done, you could have bought the EMC8000.. http://mysite.verizon.net/tammie_eric/audio/audio.html

Here is a link site for the major soundcard manufactures, but do your research before buying.. http://www.synthzone.com/sndcard.htm

Lastly, remember that the FBD is a perminent solution for your Sub, don't get caught up in buying something that is for sound measurement in that spot, unless don't mind disconnecting it from your HT every time you want to measure some sound. Thats what the rest of the equipment is for...

Good luck..

I would not suggest using the BFD for anything other than subwoofer equalization but for that purpose there nothing that can touch it at anywhere near the price. The problem is that using it properly is very labour intensive with lots of measuring and setting filters then measuring and setting filters, etc., etc.
What Room EQ Wizard appears to do is to automate everything (frequency sweep and measurement, analysis, filter setting creation) so that what used to take hours should take minutes.
The program also has a C-weighting compensation setting so that you do not have to modify your RS meter to get a flat response.

In case anyone is not aware of it here is a very good site on setting up the BFD:
http://www.snapbug.ws/bfd.htm

Thanks Dundas

Not to be a party pooper, but fixing a sub’s response for any one listening point in the room doesn’t “fix” the whole room.

Let’s suppose that at point “A” standing waves in the room provide a +6db constructive boost at 48Hz while at 32Hz providing destructive canceling by about -6db at that same point “A.” At point “B,” about 2 meters away at another seating position, the opposite occurs boosting 32Hz and suppressing 48Hz. Now using some form of detection at point “A” the user determines automatically or manually that some portion of the electronics should reduce the signal by -6db at 48Hz and boost the signal by +6db at 32Hz. A listener at point “A” now hears a “flatter, more even” response but the situation at listening point “B” is now twice as bad as it was before the measuring and adjusting.

Even the most perfect sub or system EQ done from only one measurement point means that the listener must plug one ear and locate the other at precisely the point the measurements were made to really hear every bit of the improvement. If the same frequencies are either over or under represented by the nearly the same amount at all listening points in the room, a simple one point EQ measuring and adjustment would be great.

Yes, but at least you'll have it adjusted for where you sit to enjoy your HT. At least you'll have a "sweet spot". May not be perfect for other sitting positions, but then again, my friends didn't donate any money towards the purchae of this expensive stuff, so they can shut their pie holes.

That's why they build in room EQ systems for receivers. We do the best we can until they come out with a "brain plugin"

I think that there are at least two reasons that go into including any feature in some equipment, the first is actual benefit, the second is marketing. I think marketing is the larger reason by a factor of 3 or 4 to 1. Whether or not a feature is actually beneficial is irrelevant: if consumers think some feature is a real benefit then when comparing brand A with the feature to brand B without it, the majority of consumers will pick brand A. This being the case, what company wants to be brand B is this scenario? Therefore, within six months of a company including some readily copied feature X in their mass-market models, most other companies will have their own version of feature X in their latest models. The fact that several manufacturers are including simplistic EQ in their receivers lends no real support to the dubious benefits of such a feature.

If you want room EQ to be generally beneficial in your room, you’ll need to sample about two dozen points within the listening areas of the room, toss out any oddball anomalies from the results and average the rest. After this make moderate adjustments.

A practical demonstration of why I think single-point sampling is nearly worthless:

If your computer is connected to your sound system, or can be, download a free sine wave generator. If your system-to-subwoofer crossover point is 80Hz, generate a tone of about 60Hz and play it back at a moderate volume. If you have an SPL meter, walk slowly from place to place in your room watching the readings. In my room with a steady tone I see at least a 10db swing from highest to lowest reading. Now do the same with 50Hz. Were the peaks and valleys in the same places as with 60Hz? Try again with 40Hz. After this series, try one for your other speakers by generating 120Hz and above. Even if you don’t have an SPL meter, you can plug one ear and move the other ear slowly about the room moving both horizontally and vertically. Likely you will find spots where a particular tone grows louder and other spots where the tone seems to disappear altogether.

Someone is going to say, “But the EQ systems don’t use sustained sine waves for testing.” That’s right. But consider this: every complex wave can be reduced to the sum of multiple changing sine waves. And this: musical notes are generally held long enough for some of their frequency components to establish standing waves in your room, at least momentarily. As a result, I consider the sustained sine wave example above a valid one as far as a worst-case scenario in order to point out the foibles of single-point EQ setups.

Bestbang4thebuck,

I personally, like to tune my sub to remove some of the room modes that are present no matter where you are in the room. ie a window rattles. Is that present everywhere in the room? yes..

Secondly, trying to reduce some of the boomy frequencies from my couch potato spot. This involves using the equipment I have (including a FBD) and generating a larger set of frequency tests that the amount you listed above. Then additional listening to a number of movies that I know cause problems at critical areas like Perl Harbour, LOTR, K-19, etc.

Really, we tweak these to our taste and thats the best we can ask for given room dynamics and our taste in hearing. Someone else given the same tools will come up with something different..

I am not attempting to come up with an average for the whole room. This is not a commercial theater, this is my theater and in my theater, you only have a few places to sit... By design..

Think of it as being a giant set of headphones that can hold 3 to 6 people in a 3600 cubic foot room...

I have tested most of the auto room setup equipment that comes with like the Yamaha RX2500, Denon 3805, etc. and they do a decent job of setting up a "giant headphone" for people that know zero about surround sound and like it that way.. Maybe in my books its not good enough, but I don't think its all marketing..

If you are the party type that has 50 people over, nothing will work as the room changes just by adding the warm bodies...

We all have our preferences on how to set these toys up. I am just voicing mine incase someone else finds it of interest.

Do what you like, if that involves standing on your head, kudos..

I didn’t mean to give the impression that I’m against all forms of EQ. I only meant to say that people who place a single microphone in the middle of a room and hit Auto EQ on a $600 receiver aren’t necessarily getting what they think they’re getting out of that process. I’m also saying that, because of consumer perception, receivers with such circuitry are going to be favored over those without.

Having a window with sympathetic vibration at say 42Hz is not necessarily indicative that 42Hz has ‘even strength’ everywhere in the room. On the other hand, just as a timpani ‘system,’ consisting of a variable tension drum head, a given volume of air contained below that and a ‘tuned port’ of sorts, has a natural resonance frequency, so can a room. I installed a pair of subwoofers in one room where, no matter how I placed the subs, there was a boominess if the music material ever strayed low. If I reduced the subwoofers’ overall level until that boomy frequency came into line, so much of the rest of the under 80Hz material seemed to disappear. Out came the SPL meter and signal generator. Turns out the room, with it’s fixed volume and openings, has a natural resonance about 34Hz. As a result, I had to adjust the overall sub level and placement to work well while ignoring data in the 32Hz to 36Hz range. However, while the overall tendency of 34Hz to ‘boom’ too loud still existed and an EQ suppression of 34Hz would have been helpful as far as not exciting the room’s natural resonance so much, even without EQ to reduce 34Hz, I was still able to find spots in the room where 34Hz almost disappeared. Bottom line: the behavior of standing waves is not tamed by EQ.

Which brings me back to a principle I would like to follow even if I can’t always apply it practically: deal with the source of the problem, don’t just put a Band-Aid on it. If the room (or a window) has a natural resonance because of it’s physical properties, I try to do what I can in the physical world before resorting to an electronic correction.

In the end, however, each of us does what we can, within limits, to achieve the sound we hope for. If your methods differ from mine, I have no problem with that. If the results you achieve are generally pleasing, then I offer my hearty congratulations!

May we all find the best ‘giant headphones!’