Why do so many automatic configuration systems set centers/rears to "large"? (1 Viewer)

[JeremyErwin]

Quite possibly. If you google the names of the speakers, you should be able to find some information on frequency response.

 

[Kevin C Brown]

I know that in the old days of DPL, surrounds typically didn't need to go above 7kHz. But that was a long time ago!

Maybe he meant attenuated low end response? I.e., you'd need to use a crossover anyway. ??

 

[JeremyErwin]

attenuated high end.

Take the JBL 3678

Frequency range (–10 dB): 30 Hz to 20 kHz
Frequency response (±3 dB): 45 Hz to 12 kHz

Or the

Klipsch KPT 1201
FREQUENCY RESPONSE:
67Hz-11kHz, ± 4dB

here's klipsch's complete cinema speaker catalogue

 

[Bobby T]

Lance, Jeremy's list is a list of commercial speakers. A list of THX home speakers would work better for theis conversation since we're talking about auto calibration in home receivers/pre pros.

 

[LanceJ]

Thanks Jeremy for the info/links.

As far as the commercial models go, I think I read somewhere Dolby Digital does make it to 20kHz, but near that limit it's depressed slightly for some reason (its compression format's limits?), so maybe that's why those speakers don't need to really make it up that far; Dolby on my own system for example always sounds a little rolled off compared to DTS or especially PCM.

Or....maybe in a theater they don't want true 20kHz reporduction because to allow everyone to hear those sounds, multiple tweeters pointed in different directions would be needed? Becasue the higher the frequency, the more tendency it has to "beam" i.e. narrow dispersion. And anyway, supposedly the average adult male can barely hear anything - if at all - above 15kHz, so why bother with the added expense?

 

[LanceJ]

Received a reply from a different member of C.A.S. (I originally only sent one email to their general address):

I wrote this:

HT audio systems, even for an audio nerd like myself
:^), has become really complicated the past few years.
With so many competing surround formats, i.e. Dolby
Digital, DTS, THX, Logic7, DPLII and now surround
music with *its* own set of special requirements,
people like myself are trying to get at the "roots" of
certain specifications that seem to conflict with
other specifications that also promise proper
playback.

His response:

"Hi Lance,

I spoke with a friend at Dolby and he started to explain that the big differences are in how the receiver handles its bass management. He threw some numbers at me quickly and I don’t want to misquote him. He told me that when things slow down for him a little, he will respond with accurate numbers and the Dolby spec. Please be patient and you will be rewarded. As you might know, many dubbing stages are set up at a specific reference level, say 85db. They don’t have a volume knob, per se, but mix to the fixed level of the room. My friend mentioned that the rooms are flat down to 40 Hz and he would be surprised if many home enthusiasts systems would meet that spec. based on the power requirements. I realize that you are not the average home enthusiast and might be able to meet the spec. The average mom and pop who purchase a receiver for a home theater don’t like to listen to the bass levels at spec.

More to come."

85dB? Anybody have a rough idea how much power (for the satellites) that would require in the "average" living room?

And there's that 40Hz frequency again.

 

[LanceJ]

BTW: I finally was able to read about half of that very long panel discussion in Widescreen Review magazine, the one with Elliot Scheiner, George Massenburg, etc (then Barnes & Noble closed - if I had known how long that article was beforehand....).

Their website contains the entire transcript of the discussion (the magazine uses at least four pages for the edited version) but you have to pay for it: "Home Theater Cruise: A New Surround Sound Standard Recap"

I definitely want to finish it because they were discussing how they thought there should be one standard surround configuration - for studio & home playback - for all formats: music, movies and broadcast TV.

 

[Kevin C Brown]

I have absolutely no idea what he's trying to say here. a) I have plotted the response in my room with my speakers and sub, and the opposite is usually true: I.e., I have flat freq response from 11 Hz - 40 Hz +/- 1 dB. It opens up to +/- 5 dB from 40 Hz up to around 300 Hz due to room nodes and such. It's actually easier to get really flat response at low freqs ... if you have a quality sub ... like an SVS.

b) If they are talking about running out of power at low freqs, that's one of the points! Crossover to a sub and let it handle the heavy, deep, power-hungry stuff. Sounds like he thinks "home enthusiasts" don't have subs!

c) I have encountered a few "average mom and pop" setups in my time, and have helped them calibrate their systems. In every single case they have the sub turned up too loud because they want to hear it. So his statement that they "don’t like to listen to the bass levels at spec" doesn't make any sense either.

Lance- I think *some* of the responses you are getting are from people who have a clue. But some of them are from generic customer service people who are simply reading from a script. What this person is saying doesn't make a lot of sense.

 

[Bobby T]

Me too. It seems the average mom and pop like thier movies bass heavy and loud.

 

[LanceJ]

Yea, things are still rather confusing. I'm still going to stick to the "run your system in whatever configuration it actually sounds best" philosophy, though will initially try it with the all-small + sub method (which is obviously mandatory with really tiny satellites).

But based on personal experience and solid sonic principles, I will stick with the large-ish satellite philosophy i.e. something with at least a 6.5" woofer (or a very good 5.25").

Damn I hope those automatic systems at least get the speaker levels correct, because I've never really heard of any problems with those - or especially the distance settings - so far.

 

[JeremyErwin]

CBS showed Terminator 3 quite recently-- I was surprised at the amount of low bass in the movie. (And before you doubt my ears & sanity, 1080i/Dolby Digital 5.1 films on television aren't too bad...)

 

[Bobby T]

Most modern action/adventure/sci fi films have a lot of low bass in them.

 

[LanceJ]

I finished the rest of that Widescreen Review article and whew, the WSR writer & the panelists definitely had some differences of opinion.

I could see what the WSR writer was talking about when he kept trying to explain about a seamless 360 degree sound field & how an 8 channel system (via BluRay/HD-DVD) should be able to do that, but I have to admit I'm on the side of the panelists: it is difficult enough to find proper placement for 5 speakers let alone eight. Eight! I mean, how many people have dedicated theater rooms or a perfectly-shaped living room to allow the correct placement of so many speakers? Even in ten years I'll bet the answer will still be just a tiny percentage of homeowners.

And IIRC everyone agreed that proper imaging in the front AND the rear could be accomplished with the 5.1 format. But as far as side wall imaging went, well, I'll let you read that lil' debate for yourself!

Then add the fact that according to the panelists, nearly all films are mixed using the 5.1 format, with a only a very tiny percentage in 6.1 form. The panel members were also quite upset at the notion of using electronic systems to synthesize the extra channels for a 6.1 & 7.1 system if the dvd only has 5.1 mix. This was usually followed by several panelists using the phrase "marketing scam" or something to that effect in regards to the 6.1 and 7.1 formats.

They also were a bit upset with the THX people and their advice for a home system's configuration, particularly in regards to the use of dipolar surround speakers and their placement height. To back that up WSR mentioned that the surround mixer for Lord Of The Rings used five identical speakers to mix the movie's soundtrack. They also mentioned something I've suspected for awhile: that any ambience or diffused sound effects in a modern movie desired by the director will already be contained in the left and right rear channel signals i.e. there is no longer a pressing need for special sound-diffusion speaker designs like dipoles or bipoles (which were really only needed for the old Dolby Surround/Pro-Logic days).

As far as music was concerned, that got sticky too. Panelists agreed all bass management should take place at home, not the studio - that way two different sets of filters/slopes/etc wouldn't interfere with each other. They also said 5.1 channels are plenty for music and that with very, very few expections none are mixing for anything more than 5.1 channels (and only one said he uses the LFE channel regularly - this could explain why some peoples' subwoofers do little-to-nothing on certain titles >>> remember, all these guys are supposedly using full-range monitors all the way around in their studios).

FYI: the panel emphasized several times that the paper they wrote (the .pdf one I linked to earlier in this thread) was written for audio professionals and the studio venue, not the home theater hobbyist.

There's a lot more in that six(?) page article (done in small print to boot) so if you're into this stuff, you really ought to go check it out.

 

[Brian L]

IIRC, there were a few comments made that I really do agree with.

I think someone offered the view that a set-up optimized for 5.1 music will still sound good for film soundtracks; but the opposite is not true. I agree 100% with that statement.

My current HT room has my rears on stands (tweeters at about ear height) slightly behind me, and off to the sides (I have a couch almost up to the back wall, thus placement options are non-existent). Works great for everything.

My previous home had the surrounds high up on the side wall. Fine for film, but with MC music having instruments panned to the back, it sounds dumb to hear vocals, saxophones, and guitars coming from that high up.

I also agree with the view that 5.1 is it. Asking for more is just not gonna happen. Having said that, I do have 6.1 in my room, although I am forced to go with an unconventional placement of the center back (behind the couch, firing up). It does work pretty well for the few 6.1 films I have (the opening fly over in SW EPII is killer!).

But really, how many people can accommodate 7.1, 8.1, or whatever else these guys have in mind for BluRay or HD-DVD? I have no doubt that the more channels you have, the more seamlessly the soundfield they can create, but who has the room for it?

Brian

 

[Kevin C Brown]

Couldn't resist. Some of us have room for 7.1 ...

http://img.villagephotos.com/p/2004-...5/KevinsHT.jpg

I will always say that a well done 5.1 system will best a mediocre 7.1 setup every time. But a well done 7.1 setup will likewise best a well done 5.1 system too.

 

[Bobby T]

Nice Kevin. I squeezed in a 7.1 system in my room. I do have side speakers hi on the wall, but towers in the rear. When I play surround music I use THX processing which routes the surround signal to the towers in the rear.

 

[LanceJ]

Bobby: in addition to great HT sound, I have a feeling if you wanted, your system could provide 99.9% of what a real dance club's system generates, what with a 12" sub & four 10" woofers along with tweeter horns all over the place.



Kevin: you're lucky to have all the right walls in the right places, especially with that open floor plan. I'll bet your system has a nice airy quality because of that, along with the precise imaging capabilities.

 

[Kevin C Brown]

Lance- My setup is a little bit compromised because one side is open to the kitchen. But, what I did to counteract that was to put the heaviest drapes I could find on the other side covering the sliding glass door to absorb those reflections as much as possible. Works pretty good.

Bobby- Anytime I see a 5.1 or 7.1 setup with big honkin' speakers about, I smile. The reason why is that whether you know it or not, you're going to get much better sound with a setup like yours than with in-walls or on-wall speakers.

 

[Bobby T]

Lance I actually have a 15" Titanic kit squeezed in there. And yes it can play quite loud, but 100% clean. No distortion. I have a B&K Ref 200.5 powering the 5 main speakers. So yeah we can dance club when we want. You should see my 2 year old daughter getting down.

Kevin I actually do understand how much better the sound is with bigger speakers. If I had the room I would run 4 RF7s. And even though I have wide dispersion speakers on the wall for side surrounds, they are RS7s with 8" drivers. I have a very understanding wife

 

[Kevin C Brown]

I did this trick of ... gradually.

5.1 to 6.1 to 7.1. Gradually, over 18 months. And then I gradually moved the front speakers more and more out from the walls. She actually asked once, have those speakers always been that far into the room? I said, yes, haven't you noticed before?