More than 4 subs is completly pointless :) - Page 4

Funny how FilmMixer noted changes made in one of those rooms. One LFE channel subwoofer location now, and many LFE channel subwoofer locations before.

Seems like there is only a single location for each of the L, C, and R main subwoofer locations.


http://www.avsforum.com/avs-vb/showt...5#post21474555

And lower frequencies have longer wavelengths which make the difference even less, which is why I asked about the highest frequency of interest (shortest wavelength).


I'm well aware of this. But modes are based upon room dimensions with regard to wavelength, so the same argument still applies. There is still only a worst case difference in ear position of 18cm or so, for a single seat location. If you were to measure with a mic at centre of head position, the difference between each would only be half that. Still seeing no compelling argument for multi mic position measurements to optimise for a single seat.

Have you measured your room?

You mean like one pixel = 3/8"!

Years ago, Nelson Pass had a room set up at CES wherein he had 4 front-firing subs stacked 2 per corner with the subs facing the corners. I thought he was daft and mentioned it. It was one of those experiences that changed how I looked at a problem and I never turned back.

So, yes, although your traces weren't labeled, I suspected the better front firing FR was with the sub facing the corner because it makes the most sense if the theory is sound, but how many people would place the sub in that corner facing the listener and immediately rule out the location?

Anyway, I appreciate the data and look forward to more of the same.

Bosso

Incorrect. If EQ'ing for a sweet seat, peaks or nulls outside it do not matter unless they are causing extraneous noise due to resonant behavior w/ furnishings, etc.

Even when optimizing for a sweet 'area', if you measure outside of it, there will be large excursions in spl at certain frequencies. Where do you draw the line?

If you would read my posts above, you will note that I say the theory behind the harman paper is solid, and it is useful as a first approximation when optimizing a room. Ultimately, though, trial, error and measurement are necessary.

JSS

Yes, but not for a while.

How about a compelling argument for the multi mic position based upon the physics (single LP)? I am willing to be convinced, but as yet, I have not seen anything to change my mind that 18cm difference is going to make an substantially audible change up to 80Hz.

[quote=markus767;21481755]In fact the people that have to approve a mix do:



Wow^^^ You're joking, right?




What you doubt is irrelevant. Are you ever gonna post anything concrete, or just you mistaken opinions?




This is the only obvious thing to be gathered from your posts.

I get results. How about you? Show them and we can have a discussion.

Bosso

I was talking about multiple seats not a single seat. My post was referring to Bosso's statement (and so was yours) about "collapsed sound field" at http://www.avsforum.com/avs-vb/showt...3#post21479823

You can optimize a single seat while optimizing other points as well: http://mehlau.net/audio/multisub_multeq_xt32/

Would be interesting to see how your setup behaves around the sweet spot.

How about answering my earlier question?

I'm not sure to what you're referring. The graph I posted was a sound power measurement for three different speakers: a very good set of relatively inexpensive tower loudspeakers (see also here) on top, offset below that the "matching" center channel, and a set of bookshelf speakers in the same line ~20dB below that.


Depends on a number of factors that effect all speakers, such as relative pathlength differences and the pattern of the speakers. My experience is that speakers with well-controlled directivity offer a larger listening zone than speakers with inconsistent patterns.


Not mine. For instance, there are few vocals in this set, and dissimilar performance in the L/R and C channels is very obvious.

But then again I optimize for music and you optimize for movies.

Movies, because of the visual element, are much more forgiving of even gross audio errors.



Yes, "three centers" is a very smart way to go. (For a DIY variant of your speakers, which I assume from the Peerless CSX woofers and tweeter are NHT, see kgveteran's system.)

I've wondered what a system with three very wide dispersion "centers" up front (like the NHT Classic 3C) would sound like.



Probably quite good, if one can keep the space around each speaker free of elements that could cause diffraction.

Another approach is to use speakers clean good vertical polars (coincident and Dual Concentric drivers work well here) and mount them either above or below the screen. My law school front setup.



One could (and IMO should, because audio is best heard and not seen) at a grill-cloth "drape" in front of the room to conceal the speakers. And perhaps mount them to the wall or place them on shelves rather than placing them on floor-stands.

My experience is that the surrounds can be very different from the front trio, though. In fact, in every room in which I've experimented I've gotten the most musically-satisfying results from mounting speakers with symmetrical polar response up high, and firing them straight up! I was also unable

I will experiment again now that I'm going to install a different room correction program (ARC, supplanting Audyssey MultEQ XT) and keep an open mind, though my results with Audyssey and with no RC were the same.


Ditto. My old condo had a living room with four concrete walls (floor with hardwood over, ceiling with air gap for HVAC and drywall between, back wall with drywall right on the concrete, and right side wall with a glass double-door to the balcony. I needed a whole lot of EQ to get decent performance even with a four setup that included a height sub.

I should have measurements, somewhere. Not on my current (new since then) computer, though.

OK. I don't understand the graph you posted, sorry for that. It's labeled Kef's Q900?




No, I optimize for a compromise between the 2. Wouldn't you be better off using a 4.0 or 4.1 configuration instead of fretting over the CC?

Bosso

If you want me to post anything concrete then you need to ask concrete questions. So what do you want me to post?

? I already did: http://www.avsforum.com/avs-vb/showt...1#post21481681

The measurements results of your FR at your multi-chair positions for starters. And list the measurement equipment as well, if you don't mind. IOW, show me your results, not what theory impresses you the most.

Bosso

It's not about what theory "impresses" me the most. It's about physics and psychoacoustics.

For what it's worth here are some recent graphs: http://mehlau.net/audio/multisub_multeq_xt32/

Sorry, I wasn't clear. The "top trace" I mentioned in the paragraph above is a sound power measurement (on-axis, 15 off horizontal and vertical) for Q900. The lower two traces are for the other speakers mentioned in that review, the "matching" center (which, as we can see, isn't), and a pair of bookshelves.


Absolutely not. IMO, multichannel with a hard center is the way to go for music. Even music not mixed in 5.1-channel.

The center provides a number of benefits for music. Most notably, it provides a superior anchor for the soundstage. Also, it allows wider spacing for the mains, which increases the potential width of the soundstage*

Don't forget why "stereo" is a two (rather than three) channel format to begin with: record cutting heads.

*I've found that narrower-pattern speakers don't image outside of the speaker boundaries, though controlled-wider-pattern speakers can. That's one reason I'm less certain of my preference for speakers with ≤90deg patterns through the midrange and treble than I was, say, 2 years ago. The A/B test I really want to do, and probably will this summer, is the Tannoy 12 DMT II's vs. JBL's LSR-6332 "studio monitors." I can't think of another speaker that's broadly similar in every area but has a wider pattern, and I know from personal experience the JBL's are excellent speakers. My Tannoys are a bit more efficient and have more cone area in the lower mids, but the JBL's should play at least as loud because the woofer has better thermal management for the woofer motor (Differential Drive with split opposed 3" voicecoils) and a really stout motor (2" vc) on the midrange too. Also, the two speakers are roughly the same size. So I just need to buy three of the JBL's and go.

Post #83. It was a test I did involving looking at the interaction from a dual opposed sub compared to a monopole one in room. It's a long story.


Not many I'd guess. You can't see the woofers! Not to mention a plate amp would be staring at you if it is a powered unit.



I've never seen any more than a very small change in the very top of the subwoofer range either. I guess anything is possible. Maybe if your head is next to a wall.

+1
Have you ever tried trinaural?

Is there a thread where I can read up on it?

I measured all my seats(7) and each one had a good response with a little variation at the crossover region. Basically the further away I was the mid bass would drop a bit in spl. I optimized for the main LP and hoped the other seats were good, I guess I was lucky. I am talking sub woofers, I don't even know if I took a full range sweep from the back row yet.

MK, do I recall correctly seeing pictures of your HT showing very aggressive room treatment, verging on semi-anechoic?


It seems obvious to me that the application determines the requirements, so the room is where everything starts, yet no one's talking about the room.

If you have lots of broad-band acoustic treatment in the room, room modes will be suppressed and bass response moving from 1 sub to a bunch will not vary spatial response as expected. SPL will be lower, as well.

Therefore, if I've recalled his room correctly, MK should not be able to generate intense standing waves in any subwoofer configuration, while Markus's rigid-walled room will not be able to get rid of them unless things are just right for number, placement, EQ and likely some bass trap treatment.

So... if you want to give us data, would you please be so helpful as to place it in context of the room used?

Have fun,
Frank

I don't expect, I measure because the room is the most important variable at low frequencies. All this mode calculation and "best subwoofer locations" talk one can find on forums is really meaningless. Every room is different. Only measurements will get you anywhere.
Nevertheless, multiple sources will still be beneficial even in a highly treated room. You simply can't make the room anechoic (enough).

That's kind of interesting. When I play a 2-channel music recording on my 5.1 system via PL-2, I do not like a hard center setting at all.

I have a PL-2 center width control on my receiver, with 8 positions. Position 1 is no center, position 8 is hard center (sounds like PL-2 movie).

I prefer the sound of position 2 (maybe 3), which is the least amount of center possible without having no center decode.

I find two channel music sounds best played through two channels, just the way it was intended to play and mixed. Going to 5.1 changes it. If the two front speakers are set up right and can image well, no center channel speaker is needed to anchor anything for 2ch music. If the music has ambiance mixed in it, the original two channels can do a great job of recreating it. If a good 2ch mix ain't broken, why screw with it?

No. Hadn't even heard of it before, to be honest. Your mention led me to [url=http://www.stereophile.com/musicintheround/904music/index.html]Prof. Rubinson's 2004 "Music in the Round" review.[/quote]

Honestly, I do most of my 2-channel listening in DPL2 music. I know Dr. Geddes isn't impressed with the math behind DPL2, but it seems to work well for me. Better than dts Neo:6. I'll also be trying AnthemLogic over the coming weeks. Both "music" and "cinema" modes.(No more Audyssey for me, because having to pay $500+ for a new digital board on a <3 year old $2000+ AVR is offensive to me, and I want to try ARC now that Anthem has reasonably priced receivers.)

Have you compared the trinaural box (or digital equivalent thereof) to the commonly-licensed matrices?

Because some find subjective improvements from doing so.

It's all preference, mind. And I'm not even aware of Dolby, dts, etc publishing studies showing relative preferences for 2-channel mixes compared to the same material put through their respective matrices. Though I'm sure both have done them at some point. So all we have are small-n samples. And under fairly different conditions. (And sighted at that!)

I think some of the differences in initial conditions are relevant, too. For example, JPC is using much wider-dispersion speakers than Markus or I use.

Until this past month I never used PL-2 music for the reasons that you have given. However, playing around with the center width control of PL-2 has made me reconsider my thoughts on the issue.

With the center width control at position 1 (of 8), there is no center content at all but there is surround speaker content.

With the center width control at position 2 (of 8), there is a touch of the center speaker in use along with surround speaker content.

My main speakers are set kind of wide apart, so the sweetspot seems to get larger with a bit of the center speaker in use.

I also use PL-2 music for television, and have done this for years. For music, I am kind of impressed with PL-2 music along with no hard center decode.

I'm in the midst of that but in the midst of countless other things too...