Purpose of flat response below 20Hz - Why does it matter? - Page 11 - AVS Forum
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post #301 of 585 Old 07-31-2011, 09:04 PM
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I know what part that is and I really felt it with my LLT's. I later saw that spectragraph of that scene and the sensation I felt was confirmed.

My Dual 18" LLT subs 120dB down to 10hz

 

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post #302 of 585 Old 08-01-2011, 02:57 AM
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Originally Posted by MKtheater View Post
All I know is that this



Does not sound nearly as good as this with music or movies



I measured every seat(7) and they were all within +/- 3 db's thru the whole range.


Is that information of any practical use? You are 20 dB down at 20 hz in that first graph!

The first chart looks similar to my main speakers being operated with no subwoofer in the system at all. Even the use of a subwoofer that only plays down to 20 Hz is going to sound way different than that first graph.

Anyhow, Mark Seaton gave some good advice here years ago.

First, get your system to play down to 20 Hz with the correct and adequate SPL capability. Then go lower depending on the usual conditions (room, power, size, cost, WAF, etc).
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post #303 of 585 Old 08-01-2011, 06:39 AM
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Originally Posted by J_Palmer_Cass View Post

Is that information of any practical use? You are 20 dB down at 20 hz in that first graph!

The first chart looks similar to my main speakers being operated with no subwoofer in the system at all. Even the use of a subwoofer that only plays down to 20 Hz is going to sound way different than that first graph.

Anyhow, Mark Seaton gave some good advice here years ago.

First, get your system to play down to 20 Hz with the correct and adequate SPL capability. Then go lower depending on the usual conditions (room, power, size, cost, WAF, etc).

Correct, one is with subs and the other is without. I will post another full range graph of my mains which go down to 17hz so it makes more sense. I used the wrong graph.

Here they are:

Mains only



Mains and subs which had to be tamed

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post #304 of 585 Old 08-01-2011, 08:06 AM
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Originally Posted by bossobass View Post

Lot's of folks with capable systems will co-sign Scott's sentiments. Those who continually argue against the relevance just happen to be those folks who've never experienced full bandwidth audio.

I will also "co-sign" Scott's, MKtheater's and your sentiments about ULF content. 3 Submersive HP's get me flat, in-room, to below 16 Hz. My measurement system is limited to 16 Hz for "accurate" results in the frequency domain, but it does read out to 8 Hz in the time domain plot, and it is clear that I have plenty of output down there:





The sub-20 Hz infrasonics add an impact and a sensation that is physically palpable and very real. Having experienced it, I no desire to go back. It is also abundantly obvious that the sub-20 Hz content in movies is "intended." It is so obviously correlated to the on-screen images that there is no question about the film-makers intent.

OTOH, infrasonics in music are not so well defined. While I'm sure there is a huge library of organ music with sub-20 Hz content, as well as things like the canon shots in the 1812 Overture, there is probably very little musical content with fundamentals below 20 Hz. In fact, there is probably little content with musical interest below ~40 Hz:



The tuba and contra-bassoon have some fundamentals below 40 Hz, but virtually no other instruments reach that low. This could explain DS-21's lack of interest in sub-20 Hz reproduction capability. (Note I said "explain" and that I didn't say "justify".)

My subs are set up using my own, personal "best practices" which incorporate one aspect of the Geddes setup, but none of the other nonsense. The one aspect I use is that the subs are rather randomly placed around my room, one on the front wall between the CC and right main, one on the left wall at 1/5 wall and one in the rear on the right at 2/3 wall. They are not equidistant to the LP and there is no timing or delay added to any of them. Beyond that, I don't do any of the other Geddes silliness. I don't use one large sub and multiple small subs. I don't set one sub for the calibrated level and then set the rest of the subs 6 to 12 dB lower then the first sub. And I definitely don't run my mains Full Range just to have more sources of bass.

Instead I use 3 *identical* subs, and I gain-match all of them so they all drive the room with the same energy. And I definitely use that "crutch" called Bass Management. My speakers are physically large, but I still cross them over to the much more capable subs at 80 Hz:


(The left Submersive has been moved since the pic was taken.)

Modern "best practices" dictate that Bass Management should be used for multiple reasons: amplifier efficiency, optimal bass driver in-room placement, and most importantly, ensuring that bass in the main channels gets re-routed to speaker(s) that is/are actually capable of reproducing it. "Best practices" would never entail sending bass to a speaker incapable of reproducing it. That bass would be lost, and that would be a stupid "best practice."

BTW, in the interest of full disclosure, the plots (supra) were taken post-Audyssey XT32, and there is significant improvement in the FR and the time domain provided by Audyssey. Also, they are single point measurements taken at the primary LP. They are not spatially averaged measurements. However, I only do serious listening at the position where these measurements were taken. I don't really care much what the response is at other positions. Nonetheless, I occasionally give up the primary LP to guests and sit in some of the other seats... and they sound pretty damn good too.

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post #305 of 585 Old 08-01-2011, 08:33 AM
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Sweet set up Craig! Just curious do you have experience with regular Audyssey vs XT32 and if so was there a substantial difference?
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post #306 of 585 Old 08-01-2011, 09:11 AM
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Originally Posted by gpmbc View Post

Sweet set up Craig! Just curious do you have experience with regular Audyssey vs XT32 and if so was there a substantial difference?

Thanks. Prior to getting the Integra DHC-80.2 with Audyssey XT32, I had an Onkyo Pro 885 with XT. There is not a whole lot of difference between XT32 and XT in the deep bass. XT was already very good on the subwoofer channel. However, the mid and upper bass is much better with XT32. The added filters in the main channels makes a big difference in this area. In addition, the 80.2 is a big step up in SQ over the 885 across the board.

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post #307 of 585 Old 08-01-2011, 09:14 AM
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Originally Posted by craig john View Post

They are not spatially averaged measurements. However, I only do serious listening at the position where these measurements were taken. I don't really care much what the response is at other positions. Nonetheless, I occasionally give up the primary LP to guests and sit in some of the other seats... and they sound pretty damn good too.

Craig

I'm glad you said it. I've been waiting for someone else to state the painfully obvious so that I don't always have to be the guy who has to and take the flack.

"Spacial averaging". To me, it's just compromising the primary listening position for the off chance that someone who really doesn't care is sitting "over there", a universe out of the sound field, can hear a slightly less terribly collapsed sound field.

In my experience with both Dolby and ITU placement recommendations for satellites, there is one spot where the sound field is correct. Moving out of that spot results in a completely collapsed sound field.

So, the subs FR at those peripheral seats is not worth improving if it compromises the primary listening position.

I have a seat that's up against the right side wall. It's waaay out of the sound field, but some guests prefer it because the low end is pronounced quite a bit. Some of them call it 'the massage chair'. If you try to explain the importance of flat response, sound field or any other technically correct terms of fidelity, they give you the facepalm and sit back and enjoy the massage.

I agree with your philosophy. And, BTW, for the listening with/without <20 Hz stuff, I always offer the PLP to participants, one at a time when necessary.

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post #308 of 585 Old 08-01-2011, 09:16 AM
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Originally Posted by jagzjagz View Post

I've seen some subwoofers mentioned to have flat response down to 16Hz (+-3dB).

Doesn't Dolby digital only support between 20Hz to 20,000Hz, not to mention most subwoofers & amplifiers only function in this range!?!

Does going down this "deep" just get clipped by most source amplifiers anyway?

getting back to the OP

Quote:


Doesn't Dolby digital only support between 20Hz to 20,000Hz, not to mention most subwoofers & amplifiers only function in this range!?!

the answer is no. the LFE channel and every other channel is spec'd down to 3hz

Quote:


Does going down this "deep" just get clipped by most source amplifiers anyway?

are you talking about the amplifiers that are built into the subwoofers ?

some subwoofers use hp filtering some don't. depends on the design and capabilities of the subwoofer. ported subs by design must have one. some sealed subs have them some don't

as to the question in the title of your thread, does it matter? the easy answer is it matters to those who it matters to

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post #309 of 585 Old 08-01-2011, 09:23 AM
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Originally Posted by craig john View Post

The sub-20 Hz infrasonics add an impact and a sensation that is physically palpable and very real. Having experienced it, I no desire to go back. It is also abundantly obvious that the sub-20 Hz content in movies is "intended." It is so obviously correlated to the on-screen images that there is no question about the film-makers intent.

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post #310 of 585 Old 08-01-2011, 09:33 AM
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Originally Posted by bossobass View Post

I'm glad you said it. I've been waiting for someone else to state the painfully obvious so that I don't always have to be the guy who has to and take the flack.

"Flack" from DS-21? Consider the source and ignore it.

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Originally Posted by bossobass View Post

"Spacial averaging". To me, it's just compromising the primary listening position for the off chance that someone who really doesn't care is sitting "over there", a universe out of the sound field, can hear a slightly less terribly collapsed sound field.

In my experience with both Dolby and ITU placement recommendations for satellites, there is one spot where the sound field is correct. Moving out of that spot results in a completely collapsed sound field.

I watched Sherlock Holmes yesterday with some guests. I sat in one of the "other" seats, one seat to the right of the sweet spot, but still within the screen boundary. I was pleasantly surprised at how good the system sounded even outside the sweet spot. Dialogue still locked up nicely with the on-screen image and front pans were still quite effective. The bass was even quite good. The primary downside I noticed was that the surrounds were off. The closer surround was more prominent than the further surround. That was distracting until I engaged the DSX Wides. Then even that issue went away.

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post #311 of 585 Old 08-01-2011, 11:33 AM
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Originally Posted by DS-21 View Post

It doesn't sound good just to me, mind. It seems to sound good to everyone who's actually tried it. (Except for Penn, who as mentioned didn't really know what he was doing. He seems to have thought spreading a few 8's in his room and setting them up sequentially per Geddes would give him adequate SPL in a fairly large room, and condemns the method because of his poor optimization in the design phase of the system setup.)


Sigh.....What is with all the BS?? You didnt like my blue walls (a stupid pointless remark again from you) and now posting somehow I do not know what Im doing As others astutely pointed out there are serious flaws when running bass above 80Hz. While I like some of Geddes theories, Geddes cares NOTHING about HT and that is where both yours and his setups fail miserably. You and Geddes are okay with that though because you are not remotely HT experts at all. Geddes will never be Toole and we are happy for that

If its still okay with you some of us enjoy those movies with content under 20Hz you say are plotless and silly .....I mean you are not going to dictate what everyone should like too are you??

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post #312 of 585 Old 08-01-2011, 12:20 PM
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Originally Posted by penngray View Post

Sigh.....What is with all the BS?? You didnt like my blue walls (a stupid pointless remark again from you) and now posting somehow I do not know what Im doing As others astutely pointed out there are serious flaws when running bass above 80Hz. While I like some of Geddes theories, Geddes cares NOTHING about HT and that is where both yours and his setups fail miserably. You and Geddes are okay with that though because you are not remotely HT experts at all. Geddes will never be Toole and we are happy for that

If its still okay with you some of us enjoy those movies with content under 20Hz you say are plotless and silly .....I mean you are not going to dictate what everyone should like too are you??

I must have missed that point about running bass above 80hz. What are some of the serious flaws running bass over 80hz? I think that the below 20 hz frequencies are important and am part way on my journey for incredible bass but still learning as I go.
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post #313 of 585 Old 08-01-2011, 01:08 PM
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Originally Posted by penngray View Post

While I like some of Geddes theories, Geddes cares NOTHING about HT and that is where both yours and his setups fail miserably. You and Geddes are okay with that though because you are not remotely HT experts at all. Geddes will never be Toole and we are happy for that

Geddes has a home theater. Did you really try spreading a few 8" drivers around your home theater to test his theory?

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post #314 of 585 Old 08-02-2011, 11:47 AM
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Quote:
Originally Posted by MKtheater View Post

All I know is that this

[graph with what I agree with JPC appears to be a 4th order rolloff at ~40Hz]

Does not sound nearly as good as this with music or movies

[graph showing flat response below 20Hz]

Surely you don't think that anyone is advocating a system that extends only down to ~40Hz?

What would be much more interesting is subjective changes you may note (with music, not special effects blockbusters) if you move that rolloff down an octave.

And "measuring at each seat" is rather different from taking a proper spatial average. Here's one example of a setup that would take a valid measurement for one listening position.



An equivalent would be taking measurements at ideally six points (yes, my 5-mic setup is not as good as 6 mics, which is where diminishing returns really kicks in, but the MIC-5 is so quick to use by comparison that I'm willing to live with the slight decrease in accuracy) in a single listening position and using FuzzMeasure or your measurement program of choice to average them.

(Obviously, I moved the kittens to a different room before running any sweeps. And put on earplugs.)

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Originally Posted by bossobass View Post

I know you know the difference with and without <20 Hz is a no-brainer, because you've been there with a hundred flicks.

"Flicks" are, of course, entirely out of the scope of the discussion, which is about the relevance of ULF to the reproduction of music.

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Originally Posted by craig john View Post

My subs are set up using my own, personal "best practices" which incorporate one aspect of the Geddes setup, but none of the other nonsense.

From the rest of your post, it seems you have some misunderstandings about the Geddes approach.

Also, note that I'm not saying that Geddes' approach is the only way.

Multiple, non-co-located subwoofers set up with in situ measurements is the only way I've heard to get natural sounding upper bass outside of a nearfield system. (A single sub close-by with EQ generally suffices for a nearfield setup.)

There are many approaches from that foundation. To me, Geddes' methods just seem to be the most efficient (in terms of cost, subwoofer size, processing needs, and ease/clarity of procedure) way to get there.

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I don't set one sub for the calibrated level and then set the rest of the subs 6 to 12 dB lower then the first sub.

Not sure where you got that idea, because it's not from the plain text of Geddes.

Perhaps because that's what the Harman SFM program did with three of the four subs in Dr. Floyd Toole's room? Obviously, SFM is not Geddes, and vice-versa. (That they tend to get similar results, IMO, speaks well for both approaches.)

What Geddes actually wrote actually to set one sub such that the overall bass level is lagging and add the others in sequentially. See Markus's page for the exact quotes.

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Originally Posted by craig john View Post

And I definitely don't run my mains Full Range just to have more sources of bass.

Have you tried sealing your mains (assuming they are vented) and using them as additional pressure sources to smooth out the modal region? If not, then you really have no basis from which to speak about the merits thereof.

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Originally Posted by craig john View Post

Instead I use 3 *identical* subs,

Nothing wrong with that approach from a sonic perspective, if done right. It's just inefficient, in terms of cost and floor space required.

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Originally Posted by craig john View Post

Modern "best practices" dictate that Bass Management should be used for multiple reasons: amplifier efficiency, optimal bass driver in-room placement, and most importantly, ensuring that bass in the main channels gets re-routed to speaker(s) that is/are actually capable of reproducing it.

Depends on the mains, of course.

Of course, saying don't highpass the mains if they are not stout enough to take it (big drivers in closed boxes to limit their low-end excursion).

But I subjectively have found that with mains of sufficient size (in my previous condo, 12" Dual Concentrics in the main system were "sufficient size," but 8" Dual Concentrics were not) the perceived performance increase from running them full-range was greater than the measured differences -slightly smoother response from 40-160Hz. In that system the mains were run full-range (in-room response down to ~40Hz, rather surprising considering they were 96dB/W/m broadband and in fairly small closed boxes, but that's the good side of masonry/concrete rooms) with a global sub lowpass at 120Hz and one or two of the subs set lower on their own amps based on measurements, so as to use as little global EQ as possible)

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Originally Posted by craig john View Post

"Best practices" would never entail sending bass to a speaker incapable of reproducing it. That bass would be lost, and that would be a stupid "best practice."

That's obviously true. However, your post makes me wonder if you've ever taken an impedance plot of closed-box mains. Obviously the amp isn't "working" that hard below their nominal cutoff, and nothing's getting "lost" because bass is reproduced by the subs.

Quote:
Originally Posted by craig john View Post

They are not spatially averaged measurements. However, I only do serious listening at the position where these measurements were taken.

As explained above, spatial averaging is to account for the fact that you're measuring in the statistical field of the room, and thus every individual measurement is just a statistical approximation. Not any "multiple listening positions" nonsense.

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Originally Posted by bossobass View Post

"Spacial averaging". To me, it's just compromising the primary listening position for the off chance that someone who really doesn't care is sitting "over there", a universe out of the sound field, can hear a slightly less terribly collapsed sound field.

I would expect that you knew better, really.

Quote:
Originally Posted by bossobass View Post

In my experience with both Dolby and ITU placement recommendations for satellites, there is one spot where the sound field is correct. Moving out of that spot results in a completely collapsed sound field.

Get better mains, i.e. mains with better-controlled midrange directivity. And set them up properly. You will see that problem disappear.

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Originally Posted by bossobass View Post

I have a seat that's up against the right side wall. It's waaay out of the sound field, but some guests prefer it because the low end is pronounced quite a bit. Some of them call it 'the massage chair'. If you try to explain the importance of flat response, sound field or any other technically correct terms of fidelity, they give you the facepalm and sit back and enjoy the massage.

FWIW, I have a position like that in my room, too. The daybed on the wall between the corner sub (S1) and S3.

Quote:
Originally Posted by penngray View Post

Sigh.....What is with all the BS?? You didnt like my blue walls (a stupid pointless remark again from you) and now posting somehow I do not know what Im doing :roll eyes:

Yes, I posted a true statement. You tried Geddes' method with a bunch of Velodyne 8" micro subs, and started bashing the methods because they didn't work with tiny subs.

Quote:
Originally Posted by penngray View Post

As others astutely pointed out there are serious flaws when running bass above 80Hz.

Such as?

I'm currently listening to R.E.M.'s "Green" on DVD-A with a 120Hz highpass on my mains and 120Hz lowpass on my multisubs. Everything sounds locked in the soundstage up front.

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Originally Posted by penngray View Post

While I like some of Geddes theories, Geddes cares NOTHING about HT and that is where both yours and his setups fail miserably.

Um, Dr. Geddes' listening room is a dedicated home theater, with a projector and such.

And I don't see why you'd imagine that a room with (as I understand it) 3 B&C 15TBX100's in closed boxes, 3 B&C 12TBX100's in bandpass boxes, and two or four B&C 8PS21's in the surround channels is going to "fail miserably."

Certainly, nobody who has actually heard his setup has been anything less than effusive in their praise of how it sounds on the bass.

Quote:
Originally Posted by penngray View Post

You and Geddes are okay with that though because you are not remotely HT experts at all. Geddes will never be Toole and we are happy for that

I never held myself out as any kind of "expert," only a music lover who (unlike you) has competently followed the advice of some experts and gotten results I consider that measure very well and subjectively I find exemplary.

As for Dr. Geddes, well...he did write a doctoral thesis on bass reproduction in small rooms....

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Originally Posted by penngray View Post

If its still okay with you some of us enjoy those movies with content under 20Hz you say are plotless and silly .....

Please re-read my posts, as you're not reading them with sufficient comprehension. "Movies" are entirely out of the scope of my posts.

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Originally Posted by tesseract67 View Post

Geddes has a home theater. Did you really try spreading a few 8" drivers around your home theater to test his theory?

Dunno which room it was, but yes he did scatter some Velodyne subs with 8" drivers around a room and, on the basis of the results of that experiment, begin condemning Dr. Geddes' methods. Amazing, isn't it?

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post #315 of 585 Old 08-02-2011, 12:05 PM
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Why would one take a spatial average from the LP and none of the locations are where it matters, where your ears are going to be. I take a measurement at each seat where each individual's ears would be and it is flat. I also measured top of my seat and in front of my seat and the differences are smaller than different seats. Treating a room does wonders to the response as well as proper sub placement. I also said I made a mistake on that first set of graphs, the second set was what I meant.
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post #316 of 585 Old 08-02-2011, 12:20 PM
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Originally Posted by DS-21 View Post

Amazing, isn't it?

As amazing as thinking that filling up my PM box with BS would magically fix the diffraction problem. I tried to be nice about it, and this is what I get.

I wonder which room the experiment was in? Had to have been the HT room.

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post #317 of 585 Old 08-02-2011, 12:23 PM
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"Flicks" are, of course, entirely out of the scope of the discussion, which is about the relevance of ULF to the reproduction of music.

Exactly when did this discussion become only about music? The OP doesn't specifically mention music and he makes reference to DD which would imply that the discussion is more relevent to movies than music.
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post #318 of 585 Old 08-02-2011, 12:25 PM
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Quote:
Originally Posted by MKtheater View Post

Why would one take a spatial average from the LP and none of the locations are where it matters, where your ears are going to be.

The top mic is close to my ear location. I'm a tall guy.

Quote:
Originally Posted by MKtheater View Post

Treating a room does wonders to the response as well as proper sub placement. I also said I made a mistake on that first set of graphs, the second set was what I meant.

Good treatments well-used are effective. (Most of the stuff sold as "room treatment" doesn't do much.)

Problem is, to be effective in the bass they also have to be big and (mostly) ugly. Some of us care about looks, even before considering how our SO's might react to bringing something into our homes.

An approach like Geddes' CLD walls (basically, turning half of the walls in a room into lossy surfaces at bass frequencies) is not ugly (just looks like walls) but does eat into the room's square footage quite a bit when applied to existing construction.

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post #319 of 585 Old 08-02-2011, 12:32 PM
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Originally Posted by DS-21 View Post

"Flicks" are, of course, entirely out of the scope of the discussion, which is about the relevance of ULF to the reproduction of music.

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Originally Posted by jagzjagz View Post

I've seen some subwoofers mentioned to have flat response down to 16Hz (+-3dB).

Doesn't Dolby digital only support between 20Hz to 20,000Hz, not to mention most subwoofers & amplifiers only function in this range!?!

Does going down this "deep" just get clipped by most source amplifiers anyway?

I think you are the only person here who thinks that movies are out of scope for this discussion. The OP never mentioned that he was only interested in multi-channel or stereo music. The initial conversation was regarding ULF with DD recordings and any possible filtering that may occur below 20Hz. It has been shown that DD does not filter below 20Hz. conversation done. You choose to only want to discuss music, particularly music that you subjectively like. That kind of seems like a straw argument to me.

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Originally Posted by DS-21 View Post

Have you tried sealing your mains (assuming they are vented) and using them as additional pressure sources to smooth out the modal region? If not, then you really have no basis from which to speak about the merits thereof.

This also cracks me up, as you yourself have repeatedly stated that you are not a fan of certain films/genres, and that they don't get played in your home. It seems like you are berating someone for having no basis from which to speak on a topic while you are proudly declaring that you do not have a basis from which to speak on others. Yet that contradiction/hypocrisy doesn't seem to register to you apparently.

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Originally Posted by DS-21 View Post

Actually, that "fact" is what is very much in dispute. Especially the second part, at least wrt everything but recently released special effects plotless wonders.

...

What does a movie sound-man have to do with serious audio? If you had listed a credit for producing an album (or a concert video) for the Royal Concertgebouw or Radiohead or R.E.M. or R. Kelly I might have given the reference more weight. (Specific artist names chosen for alliteration as much as anything else.) But movies? Blah. Don't care.

What does a sound-man have to do with audio? Really? That is a very weak argument. Again, here you seem to want objective definitions/empirical evidence that conform to your subjective interpretations/tastes/conclusions. That's just poor science, and poor argumentation.


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Originally Posted by DS-21 View Post

D) You still haven't said what the title of the film you abbreviated is. How is one who doesn't particularly follow Hollywood supposed to know what you're talking about, even to the point of looking it up on a review site?

This was just silly BTW. Try Google, its free. The first 6 responses gave the title of the film. This took all of 3 seconds, maybe, to find out. This question at best makes you look obstinate and lazy and at worst makes you look incapable of doing any research/effort on your own. This underscores others comments that you are not willing to put any effort into anything except arguing. At least put some effort into doing that well though.

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post #320 of 585 Old 08-02-2011, 12:33 PM
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Originally Posted by mojomike View Post

Exactly when did this discussion become only about music? The OP doesn't specifically mention music and he makes reference to DD which would imply that the discussion is more relevent to movies than music.

Because that point - that current releases of special effects blockbusters have ULF content at perceptually-relevant levels - has been long ago conceded. We might argue why that content is there* But the fact is that it's there, and someone who cares about getting everything on the disk of such a movie will probably want to be able to reproduce that content at home.

*My view - based on the understanding that Hollywood is about churning revenues, not making art - is that the "ULF wars" are simply cynicism. Getting on "best bass lists" will sell disks in a declining market. I also suspect that the trend of more and more ULF content will last exactly until someone blows up their HT and sues a studio for putting in content that they know or should know a typical consumer's HT can't handle, (Or do such movies already have a warning like the Telarc sonic spectaculars? I don't know, as I'm not interested in them.)

If someone else wants to get into the philosophy of "high fidelity" as it pertains to cinematic releases (i.e., is "fidelity" in that context actually "an experience like viewing a film in a typical cinema, the environment for which the program material was created in the first place," or is it "playing everything encoded on a disk") might be of interest to some, but I don't care enough about movies except to point out that Bosso and others are implicitly assuming the latter definition. Perhaps justifiably, mind. But it is a front-end assumption.

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post #321 of 585 Old 08-02-2011, 12:43 PM
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Originally Posted by Snowmanick View Post

I think you are the only person here who thinks that movies are out of scope for this discussion. The OP never mentioned that he was only interested in multi-channel or stereo music. The initial conversation was regarding ULF with DD recordings and any possible filtering that may occur below 20Hz. It has been shown that DD does not filter below 20Hz. conversation done.

Of course, conversations often move beyond the initial topic, in audio fora and in real life. As you point out, the discussion has been narrowed in scope, because nobody's arguing that there isn't ULF signal present in some movie disks.

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Originally Posted by Snowmanick View Post

This also cracks me up, as you yourself have repeatedly stated that you are not a fan of certain films/genres, and that they don't get played in your home.

There is no inconsistency between the statement you quoted and my statements about movie genres.

Any reasonable person will see that the distinction there is between:

a combination of measured performance and subjective preferences thereof regarding program material generally (running mains full range), and

subjective preferences as to specific source material.

As you can see, neither statement is remotely within the scope of the other, so they cannot be inconsistent. (Or consistent, for that matter.)

Also, note that two of those three things are subjective, individualized preferences. (Measured performance is the one that's not, obviously. I shouldn't have to write that, but I feel like I do...)

I'm not trying to force my preferences on others by any means. I'm trying to share what has worked for me. And originally, recall, I was asking for evidence of intentional perceptually relevant sub-organ-pedal content in music.

If someone can provide such evidence, then as someone interested in high fidelity reproduction of music I must change my position. Why? Because the evidence does not support my position.

But thus far, the only evidence presented has been the existence of 13Hz signal in a Sting track from 1999. But no attempt has been made to state how that correlates to anything in the music. Just that it's there. Interestingly, another post has shown microphone artifacts in that general area...

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Originally Posted by Snowmanick View Post

What does a sound-man have to do with audio? Really?

Yes.

What does the resume of a sound man showing a bunch of high-grossing and undoubtedly slickly-produced films have to do with the reproduction of music?

Even as an argument based on appeal to authority, it was just weak because the "authority" was out of the scope of the discussion.

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Originally Posted by Snowmanick View Post

This was just silly BTW. Try Google, its free. The first 6 responses gave the title of the film. This took all of 3 seconds, maybe, to find out. This question at best makes you look obstinate and lazy and at worst makes you look incapable of doing any research/effort on your own. This underscores others comments that you are not willing to put any effort into anything except arguing. At least put some effort into doing that well though.

Do you have anything meaningful to say, or are you just going to attack me?

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post #322 of 585 Old 08-02-2011, 12:58 PM
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Originally Posted by DS-21 View Post

Because that point - that current releases of special effects blockbusters have ULF content at perceptually-relevant levels - has been long ago conceded. We might argue why that content is there* But the fact is that it's there, and someone who cares about getting everything on the disk of such a movie will probably want to be able to reproduce that content at home.

*My view - based on the understanding that Hollywood is about churning revenues, not making art - is that the "ULF wars" are simply cynicism. Getting on "best bass lists" will sell disks in a declining market. I also suspect that the trend of more and more ULF content will last exactly until someone blows up their HT and sues a studio for putting in content that they know or should know a typical consumer's HT can't handle, (Or do such movies already have a warning like the Telarc sonic spectaculars? I don't know, as I'm not interested in them.)

If someone else wants to get into the philosophy of "high fidelity" as it pertains to cinematic releases (i.e., is "fidelity" in that context actually "an experience like viewing a film in a typical cinema, the environment for which the program material was created in the first place," or is it "playing everything encoded on a disk") might be of interest to some, but I don't care enough about movies except to point out that Bosso and others are implicitly assuming the latter definition. Perhaps justifiably, mind. But it is a front-end assumption.

You are making the assumption that movies are produced primarily with a public cinema in mind. While that may have been true a long time ago, that is simply not true any more. There is far more money to be made long-term when the movies are released for the home market. There are in the theater for what, a month or two? They are later sold in disk form, or rented for download, or broadcasted for many years to come.

Most of us who frequent this forum have systems who's sound easily surpassed the sound of most poblic cinemas. Personally I enjoy movies at home more than I do in most public theaters. Imax (the real ones) do a pretty good job with dynamics and clarity, but the bass depth is still better at home.

Your distain for action-type movies puts you in the smallest of minorities here on this forum. It makes me wonder why you even bother to hang out here.

About the only thing that I can agree with you about is that live music is indeed the gold standard for judging whether your system's bass sounds accurate. By comparing to live music, both acoustic and unamplified as well as amplified, you can evaluate how the system sounds comparing with something real as opposed to artificial movies sound effects. However, the vast majority of us here do enjoy those artificial sound effects. We like to listen to them, measure them, and talk about them.

What are you doing here exactly?
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Do you have anything meaningful to say, or are you just going to attack me?

Honestly, the latter would probably be more fun, but I was originally posting in response to your declaration that movies are beyond the topic of this conversation. You seemed to thread jack this whole discussion, and then declared yourself master over its contents. Simultaneously you write off views/material other than those favored by you, even if they are within the scope of the discussion. Again, poor science and argumentation.

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We first want our system to play accurate music, and then we make sure it can handle movie dynamics as well. Basically I make sure mine can play accurate loud music and I am covered for HT.
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post #325 of 585 Old 08-02-2011, 01:06 PM
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Originally Posted by DS-21 View Post



...using FuzzMeasure...

(Obviously, I moved the kittens to a different room before running any sweeps. And put on earplugs.)

Obviously you do not understand how FuzzMeasure actually works. The fuzzy things have to stay in the room! Duh!
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post #326 of 585 Old 08-02-2011, 01:14 PM
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Obviously you do not understand how FuzzMeasure actually works. The fuzzy things have to stay in the room! Duh!

Nice

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post #327 of 585 Old 08-02-2011, 03:03 PM
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Originally Posted by DS-21 View Post

From the rest of your post, it seems you have some misunderstandings about the Geddes approach.

Also, note that I'm not saying that Geddes' approach is the only way.

Multiple, non-co-located subwoofers set up with in situ measurements is the only way I've heard to get natural sounding upper bass outside of a nearfield system. (A single sub close-by with EQ generally suffices for a nearfield setup.)

There are many approaches from that foundation. To me, Geddes' methods just seem to be the most efficient (in terms of cost, subwoofer size, processing needs, and ease/clarity of procedure) way to get there.
Not sure where you got that idea, because it's not from the plain text of Geddes.

Perhaps because that's what the Harman SFM program did with three of the four subs in Dr. Floyd Toole's room? Obviously, SFM is not Geddes, and vice-versa. (That they tend to get similar results, IMO, speaks well for both approaches.)

What Geddes actually wrote actually to set one sub such that the overall bass level is lagging and add the others in sequentially. See Markus's page for the exact quotes.

I guess I thought you were referencing Geddes' approach here:

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Originally Posted by DS-21 View Post

Now, take those two ACI Titans, which each a closed-box subs with a ~13mm xmax 12" woofer in a fairly large cabinet, and attenuate them relative to the ULS-15 by let's say somewhere between 3 and 15 dB, depending on what measurements say give the smoothest in-room response. What are the chances they will overload at any frequency before the main sub?

I thought you had said 6 to 12 dB when, in fact, you said 3 to 15 dB. Other than that, I had it pretty much right.

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Have you tried sealing your mains (assuming they are vented) and using them as additional pressure sources to smooth out the modal region? If not, then you really have no basis from which to speak about the merits thereof.

My mains are sealed. They are an LCR design, and the manufacturer elected to roll them off at 60 Hz in an effort to raise the *system* sensitivity. Paul Scarpelli, (the guy I quote in my signature), is the former Director of Marketing for Triad. When I bought my speakers, he PM'd me to say specifically that they were designed to be used with subwoofers and a crossover of 80 Hz, and that I would be disappointed with the results if I ran them Full Range. Of course, I already knew that, and I had actually taken that into consideration before I bought the speakers. In fact, it was one of the primary criteria I used in selecting them.

And then for you to say, "...you really have no basis from which to speak about the merits thereof." is simply ignorant. You clearly had no idea what my basis was for saying that.

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But I subjectively have found that with mains of sufficient size (in my previous condo, 12" Dual Concentrics in the main system were "sufficient size," but 8" Dual Concentrics were not) the perceived performance increase from running them full-range was greater than the measured differences -slightly smoother response from 40-160Hz. In that system the mains were run full-range (in-room response down to ~40Hz, rather surprising considering they were 96dB/W/m broadband and in fairly small closed boxes, but that's the good side of masonry/concrete rooms) with a global sub lowpass at 120Hz and one or two of the subs set lower on their own amps based on measurements, so as to use as little global EQ as possible)

If you set the mains to Full Range, and there is content in the main channels below their -3 dB point, what happens to that content?

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That's obviously true. However, your post makes me wonder if you've ever taken an impedance plot of closed-box mains. Obviously the amp isn't "working" that hard below their nominal cutoff, and nothing's getting "lost" because bass is reproduced by the subs.

Let me ask again... If you set the mains to Full Range, and there is content in the main channels below their -3 dB point, what happens to that content?

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[pointless ad hominem attack deleted]***

The "pointless ad hominem attack" that you deleted was this: "In your little world..." Wow, now that's pretty bad. I never should have said that.

However, you run around here all day long calling people incompetent and unreasonable, daft, silly and mindless, and all sorts of other insulting and demeaning things??? You tell people their posts are "bleating", (really???? the sound made by a goat???), that peoples' reading comprehension skills are lacking and that none of us has ever experienced a "properly setup multi-subwoofer system."

If you're going throw out "pointless ad hominem attacks" at everyone, you should at least be less sensitive to them yourself.

Craig

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post #328 of 585 Old 08-02-2011, 03:12 PM
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Originally Posted by DS-21 View Post


But thus far, the only evidence presented has been the existence of 13Hz signal in a Sting track from 1999. But no attempt has been made to state how that correlates to anything in the music. Just that it's there. Interestingly, another post has shown microphone artifacts in that general area...

What does the resume of a sound man showing a bunch of high-grossing and undoubtedly slickly-produced films have to do with the reproduction of music?

Everything I posted were just artifacts? Could you please explain to me? So after the bass drum is hit, or in that one song where the ULF spikes twice and there is an increase in ULF, that is just the mic(s) of the recording company producing distortion? or some random from the outside environment?

I have not disregarded Geddes set-up either. You use a 2nd order crossover at 150 Hz and use drivers that play up to 600 Hz? At 150 Hz the 45 degree phase shift is about .94 ft. and at 300 Hz it is about .47 ft. and 600 Hz it is about .24 ft. if I did my math correctly. If the way I word this sounds like my second language it is because I am an amateur at speaker design.

Now we have 5 sources reproducing the mid-bass of the content. If the response is spatially averaged, won't that lead to random phase shifts I think also known as acoustical interference?

Does this approach smooth out the sound since the waves won't be arriving at your ear all at the same time? It is easier to distinguish when a group plays an A3 note on the cello verses when they all play an C2. When I tried learning guitar a few ago, the chorus pedal was more noticeable on the upper pitched strings versus the three thickest. (I am not sure the science behind the chorus pedal but without the modulation effect, it makes the sound smoother as if more people are playing).

Thanks for your response in advance.

Some movies use real recorded sounds. Does this make them any less worthy to music where the dynamic range compression is high in most recordings today, or when auto-tune is added? Even some highly prestigious recording companies with low dynamic range compression still clip the signal.

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post #329 of 585 Old 08-07-2011, 11:16 AM
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Originally Posted by vraxoin View Post

Obviously you do not understand how FuzzMeasure actually works. The fuzzy things have to stay in the room! Duh!

Haha! Thanks for the levity.

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Originally Posted by mojomike View Post

You are making the assumption that movies are produced primarily with a public cinema in mind. While that may have been true a long time ago, that is simply not true any more.

Please, please, PLEASE understand what you're reading before you comment on it next time, OK? A little bit of reading comprehension goes a long way!

In the post you quoted, I merely pointed out that there were competing philosophical views on the concept of "fidelity" as it applies to the home rescreening of movies, whereas other people are making an assumption and proceeding accordingly. I took no position as to the correctness of either view.

Well, not quite true: the position I took was basically the opposite of what you falsely ascribed to me. What I actually wrote was that the assumption Bosso et al. make is "probably justified" (how can someone so blatantly miss such clear language?) but that I don't personally care either way.

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There is far more money to be made long-term when the movies are released for the home market. There are in the theater for what, a month or two? They are later sold in disk form, or rented for download, or broadcasted for many years to come.

Funny thing is, you write that while betraying an abject lack of comprehension as to what it actually means.

IF what you write above is true - and I'll assume arguendo that it is - it weakens the case for the relevance of ULF in movies rather than bolstering it. Why? Because that means releases will be targeted to people who watch them through their television speakers, not the tiny handful of people willing to have 10+ L of volume displacement and multiple kilowatts to push it in their rooms.

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Originally Posted by mojomike View Post

Most of us who frequent this forum have systems who's sound easily surpassed the sound of most poblic cinemas.

I agree. Though a big part of the reason cinemas sound so bad is that they're so damned loud. We saw that Steve Carrell/Julienne Moore comedy last weekend. It's just not realistic to have people talking at those SPL's.

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Your distain for action-type movies puts you in the smallest of minorities here on this forum. It makes me wonder why you even bother to hang out here.

Why? That's rather narrow-minded of you.

For the record, my reference living room system's multiple subwoofers combine to about 8.5L volume displacement - Aurasound NS15-992-4A, 2x Aurasound NS12-794-4A, Aurasound NS10-794-4A - in about 12.5 cubic feet of total cabinet volume, pushed by ~2.5kW. So obviously I care about bass performance. Not as much as some, perhaps, but more likely than not in the top 1% of posters even in this and the DIY subfora. (And unlike many with very large bass subsystems, large and powerful subs are appropriate to the the scale of my system, given that my mains each have ~525 cm^2 of radiating area, are about 96dB/W/m efficient, and rated to handle 450W.)

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Originally Posted by mojomike View Post

About the only thing that I can agree with you about is that live music is indeed the gold standard for judging whether your system's bass sounds accurate. By comparing to live music, both acoustic and unamplified as well as amplified,

Unamplified, not amplified. Unless one wishes a system to sound like a PA. For instance, last week we saw Sia play at a small venue. The performance was excellent. The sound? Fortuntately, the performance was excellent.

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Originally Posted by mojomike View Post

However, the vast majority of us here do enjoy those artificial sound effects. We like to listen to them, measure them, and talk about them.

Obviously, nobody is even asking you to do that.

However, when there has is general agreement about an issue, I don't get why people keep bringing it up

The reason special effects blockbusters are out of the scope of the discussion is because nobody disagrees - or cares enough about the subject to disagree on this thread, at any rate - about ULF in them.

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post #330 of 585 Old 08-07-2011, 11:57 AM
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Originally Posted by craig john View Post

I guess I thought you were referencing Geddes' approach here:

I was stating a likely outcome, based on my experience applying Dr. Geddes' method, yes.

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Originally Posted by craig john View Post

My mains are sealed. They are an LCR design, and the manufacturer elected to roll them off at 60 Hz in an effort to raise the *system* sensitivity.

Please tell me how running your mains without an electrical highpass will change any bit of that.

Make sure you understand the implications of a sealed system's impedance under resonance before answering the question.

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Paul Scarpelli, (the guy I quote in my signature), is the former Director of Marketing for Triad. When I bought my speakers, he PM'd me to say specifically that they were designed to be used with subwoofers and a crossover of 80 Hz, and that I would be disappointed with the results if I ran them Full Range.

Two thoughts.

First, at least in your truncated account, you're simply misinterpreting what Mr. Scarpelli told you. It reads as if he was trying to discourage you from running them without subs, not from running them without a highpass with overlapping subs.

Second...oooh, a PM from marketer. I think it's telling you think "a PM" (likely misinterpreted on your end at that!) from the marketing director of a speaker vender should be accorded more weight than
(a) published advice of noted experts in serious audio with numerous peer-reviewed publications under their belts, combined with
(b) personal experience implementing the recommendations from (a).

For the record, a search on for "Paul Scarpelli" in the AES library comes up entirely empty. Zero hits. And a search for the affiliation "Triad" pulls up two references...from the 1950s from a transformer maker of that name.

By contrast, a search for "small room" authored by Geddes turned up three results, the top one being directly on-point to the discussion.

Third, I think it's worth noting that your signature quote is contradicted by the results of actual research by Toole, Olive, et al. Not to mention being entirely over-simplified. It doesn't take a genius to realize that a "good" room for speakers of one radiation pattern may be a "bad" room for speakers of another radiation pattern. And a person who lives in the real world and approaches high-fidelity reproduction with due care is more likely to fit the loudspeakers to the room, rather than the other way around.

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Originally Posted by craig john View Post

Of course, I already knew that, and I had actually taken that into consideration before I bought the speakers. In fact, it was one of the primary criteria I used in selecting them.

What was? A speaker that traded bass extension for efficiency? A good idea in a modern system, IMO. Though I'd want a bit more than a real-world 90-91dB ideally...

I've not heard those speakers. Based on the driver complement, driver topology, and third-party measurements, I would expect them to sound good. At least for seated listeners. (One of the reasons I use Dual Concentric drivers is that I find myself occasionally listening to music standing, so vertical polar response matters to me too. I expect I am idiosyncratic in that regard.)

But, I'm curious, and mains are more interesting than subs anyway: given that your speakers are behind a screen you have no aesthetic issues about which to worry, so why would you compromise your front stage by using a center channel that's so different from your left and right speakers?

According to a review of your speakers I found online, the center is rather different in response from the left and right in the midrange, as one would expect from the different baffle shape/diffraction signature, and presumably a different crossover:

L/R, on axis, 45deg an 60deg horizontal off axis:


Center, same angles:


Frankly, a non-matching center makes about as much sense as non-matching left and right speakers. All three share the task of presenting the front soundstage, and differences in them are especially glaring to any critical listener.

Moreoever given that Triad seems to be primarily a made-to-order operation, crafting three properly identical front speakers does not seem like it would present them any special difficulties. Did you ask them for a properly identical front set but allow yourself to be led astray by their marketing guy?

Quote:
Originally Posted by craig john View Post

And then for you to say, "...you really have no basis from which to speak about the merits thereof." is simply ignorant. You clearly had no idea what my basis was for saying that.

You've posted nothing that would lead a reasonable person to conclude I was in the slightest incorrect about you having no basis from which to speak about the merits here.

Quote:
Originally Posted by craig john View Post

If you set the mains to Full Range, and there is content in the main channels below their -3 dB point, what happens to that content?

Um, it gets reproduced by the mains and the subs, and the overall reproduction of it is accurate because the system was calibrated to account for the overlap.

I presume most modern equipment has a mode like Denon's LFE+Main, wherein signal below the sub highpass is simultaneously directed to the mains and the subwoofers.

Quote:
Originally Posted by craig john View Post

Let me ask again... If you set the mains to Full Range, and there is content in the main channels below their -3 dB point, what happens to that content?

Fair enough, I'll answer again. Forgive the cut-and-paste.

Um, it gets reproduced by the mains and the subs, and the overall reproduction of it is accurate because the system was calibrated to account for the overlap.

I presume most modern equipment has a mode like Denon's LFE+Main, wherein signal below the sub highpass is simultaneously directed to the mains and the subwoofers.

Quote:
Originally Posted by craig john View Post

However, you run around here all day long calling people incompetent and unreasonable, daft, silly and mindless, and all sorts of other insulting and demeaning things???

Those things, in the context in which they are used, are true.

However, "my world" is, if anything, way bigger than the average person's. Why? Regular global travel, for fun, family, and business. So your statement was demonstrably untrue.

Quote:
Originally Posted by craig john View Post

that peoples' reading comprehension skills are lacking and that none of us has ever experienced a "properly setup multi-subwoofer system."

Both of those statements, judging by the content of other's posts, are entirely correct when I use them.

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