Quote:
Originally Posted by
MKtheater 
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.)
Quote:
Originally Posted by
bossobass 
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.Quote:
Originally Posted by
craig john 
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.
Quote:
Originally Posted by
craig john 
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.
Quote:
Originally Posted by
craig john 
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.
Quote:
Originally Posted by
craig john 
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.
Quote:
Originally Posted by
craig john 
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)
Quote:
Originally Posted by
craig john 
"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 
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.
Quote:
Originally Posted by
bossobass 
"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 
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.
Quote:
Originally Posted by
bossobass 
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 
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 
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.
Quote:
Originally Posted by
penngray 
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 
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....
Quote:
Originally Posted by
penngray 
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.
Quote:
Originally Posted by
tesseract67 
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?