A pro talks about bass management issues for surround *music* playback (1 Viewer)

[LanceJ]

"High-Resolution Mixing in 5.1 — the Chuck Ainlay Way ~ Part Two"

Scroll down to the paragraph labeled "Bass Management — Avoiding the Pitfalls" (the HFR site has a stern warning about copy/pasting parts of their articles-whatever. ).

I've mentioned the issue of bass management for 5.1 music several times here after lurking on pro forums, reading about it in this white paper ("Recommendations for Surround Sound Production") and doing a few of my own little experiments. But to avoid b.m. problems in the first place and simply to reproduce the music in the best possible manner*, pretty much all surround engineers advise using full-range speakers all the way around, along with a sub in case the engineer happens to choose to use the LFE channel....which some surround recordings don't use.

FYI: whenever someone says "full range" speakers, some people immediately start complaining about having five huge floorstanders with dual 12" woofers in 8 cubic foot cabinets sitting in their living room. Ummm, no. Because based on what I've read, those engineers mostly seem to want people to not use tiny satellites with five inch and smaller "woofers". I have to agree because 99% of the speakers I hear equipped this way seem to have a hard time realistically reproducing certain important instruments-bass guitars, pianos, certain drums-and male voices and it doesn't matter if a subwoofer is used.

As I've also said before, to me a speaker finally sounds nearly "full" when a 6.5" woofer is used when used to play back my type of music and in my living room. Usually only bass drums and church organs get left out in the (sonic) cold but I can still sense their presense. And no, this size woofer can't reproduce the extreme low bass that shakes couch cushions, but I'm talking about MUSIC reproduction here, not a starship's hyperdrive engine or explosions in a WWII movie.

Lastly, sonic artifacts generated from badly-configured b.m. systems-i.e from room and ELECTRICALLY-based phase cancellation effects, and incorrect crossover points-aren't as noticeable with movies because:

1) many of their audio effects are artificially generated so there is no way to know what those effects are supposed to truly sound like. >>> But with a piano, a drum or Mr. Springsteen's voice, there ARE solid reference points for music fans to base their judgements on.

2) a movie's soundtrack is mostly an intermittant situation so problems can occur without being noticed right away. >>> But a dvd-audio, sacd or DTS-CD plays music continuously, so any serious sonic aberrations during music playback are more easily identified.

I realize all this may put a damper on some people's opinion of surround music, but I finally realized that like any other quality sensory experience-good food, fast cars, etc-this format needs extra care to get it to work properly.

* due to this research, both of my rear channels are now speakers that use 8" woofers, just like the front mains-both pairs' response reaches to the low 40s; my center channel is now a large-ish bookshelf with a dual ported 6.5" woofer and IIRC reaches to 55Hz. I use no bass management; this goes for movies too. BTW: I don't listen at reference level so my receiver is never needlessly overtaxed. Folks, switching just the rears from Realistic Minimus models (2-way with 5" woofer in an aluminum cabinet) to the larger speakers made a huge difference, and I'm not one to throw around adjectives like that either. Surround music listening definitely became more enjoyable!

>>> Also, check out page 2-5 in that white paper for correct speaker placement for surround MUSIC listening.

 

[Kevin C Brown]

It's interesting because even before reading the above info, my personal impression was that for me in my room, similarly, a ~6" woofer was roughly the cutoff.

So if I dig up some specs for mine:

L&R: -3 dB at 30 Hz
center: -3 dB at 38 Hz
surrounds & rears: - 3 dB at 45 Hz

For movies, I do use the BM in my pre/pro. But for SACDs and DVD-A, to end the hassle with BM and phase , I've been using all large, sub on for over a year now. Most music doesn't have a lot of content below 40 Hz anyway. Works well for me.

The funny part? I didn't remember what drivers my current surrounds/rears had off the top of my head, so I went and checked. I also checked the last 2 systems I've had in here. All are 6.5".

Obviously, a lot of things go into bass extension and response, but the driver size is one major factor.

 

[ChrisWiggles]

I don't really understand the point of this thread, this is the only statement that I can find here that seems to be a driving statement:


in which case this is certainly not news, but I am very confused about whether you were trying to argue about BM or not, or speaker size or not or what exactly...

 

[LanceJ]

Kevin: wow, 30Hz? If you absolutely had to, I bet you could choose "no sub" & not be missing much, if anything, on most surround music titles.


Here's the short & sassy version: DON'T USE TINY SPEAKERS IF YOU WANT TO HEAR SURROUND MUSIC PROPERLY!



IMO a lot of people have been convinced sub/sat systems with fits-in-your-hand satellites are the "thing" to own if they want great sound (but I won't get into which manufacturer I think started this falsehood-hmmmm). This marketing blitz started around 1990, even though subwoofers had been around for decades before that. So I just wanted to let others know that the people who actually put together the music we listen to-and AFAIK, have no financial motives behind their opinions-have a totally different view of this issue.

I have noticed that for many that come here, while they enjoy listening to music (and/or watching movies) they aren't always audio hobbyists & are just seeking advice for building a nice system.....and once it is built, they no longer want to fuss with it. And they don't feel like digging around the 'Net and going through pages and pages of brain-melting technobabble just to find an answer to a couple of basic questions and may be hesistant about publicly asking them (i.e. "lurkers").

One of the situations that really got me to researching the b.m. issue was that quite a few people said they thought the bass on dvd-audio titles sounded boomy. On my system and systems I helped configure, I never noticed this effect on any title that I own. Well, it turns out a very popular universal hi-res player, the Pioneer DV-563*, was reported to have a crossover point for the dvd-audio format all the way up at 200Hz!! Yikes! At least on the subs I know of, such a stratospheric crossover point will definitely cause boominess. And since many subs have optional LFE inputs that bypass the sub's internal adjustable crossover system, an owner of such a system-especially the person I described above-would naturally think the disc is causing the boominess problem (BTW: sacd's crossover point on this player is reported to be set at 120Hz, better but still not low enough IMO). I didn't do any scientific surveys, so I'm not saying this was the problem with EVERY boomy system that played dvd-audio discs, but to me it sure seemed like a very plausible theory and I still do.

I used to kind of worry about what to tell people that wanted to get into 5.1 music because of the lack of b.m. on many players (or the b.m. that is there isn't implemented properly) and that they would get turned off to it if they were told they need "X" size speakers. Finally I just came to the conclusion that just like owning a fussy sports car, you're going to have to make some sacrifices if you want to experience this format in the best way possible.

* I own a Pioneer DV-656A (North American version)

 

[Kevin C Brown]

Can't do it and won't do it, and you probably know the reason why too.

Most universal players still have 2 problems that earlier players had (or maybe 3!):

a) If you choose "no center", they do not mix the original center channel into the L&R.

b) If you choose "no sub", then they also don't re-direct that low freq material to any of the main channels.

c) If you choose no center, no sub, and no surrounds, then they won't downmix to two channel. Although why anyone would buy a 5.1 universal player to hook it up to a stereo system, I have no idea.

All of those are only for the DVD-A and SACD discs. I think the DVD forum says that for DVD-Vs, players have to do all of the above. But a lot of them won't do those things for DVD-As or SACDs.

 

[ChrisWiggles]

Ok, now we're seeing your actual argument clearly, so I can move to disagree.

You are oversimplifying. Certainly I agree that sub/sat systems that cannot fully cover the freq range are ineffective, and I would agree that "tiny" speakers will not match well with a subwoofer based on the laws of physics and freq extention of "tiny" speakers. However, I firmly disagree that monitor-sized speakers with a subwoofer and well-implemented BM are not effective. I would argue firmly that such a system can be done at lower cost, or at higher performance for the same cost and is a superior choice except where money is not really a limiting factor.


How is this any different than any high quality audio system. The same applies to Compact Discs too. There are a lot of CD systems out there in two-channel only with difficulties in bass management, and huge complications in implementation even without a subwoofer, and even without strong bass extenstion in the system at all. You're enlightenment is not news that I can see, except for your desire to indict some absurd theory about "bass management" conspiracy theories and subwoofer manufacturers. Better to accuse Pioneer to further your theory, wouldn't it?

 

[LanceJ]

I'm just guessing, but I still think the chips that can do b.m. on six hi-res channels are quite expensive & since 5.1 music ain't exactly breaking any sales records, the economy of scale thing isn't going to kick in any time soon and lower these chips' prices for the entry-level & mid-fi players. :frowning:

 

[ChrisWiggles]

why does economy of scale concern you, after all as you say (and I don't necessarily disagree with this part) high-res m-channel is a fussy sports car, not an entry or mid-end thing. If you're going to pull off any audio system right, it costs, and if you're going to multiply that 2.5 fold for 3 more channel, you're not skimping cash on players and processors exactly.

 

[LanceJ]

Chris:



Er, I think you read my posts too fast.

 

[LanceJ]

I didn't check on which player you owned, so was making sort of a casual comment. BTW: I have read here and elsewhere where some people think the LFE channel for 5.1 music is simply for bass *reinforcement*, so they elect not to use a sub at all, even if they already own one. That's not correct: many times the mixing engineer places important instrmuments there, and only there. So if a surround rig's b.m. system doesn't do the LFE redirection thing, a sub must be used so everything can be heard.

 

[Dick Knisely]

Might be just me Chris, but I think you and OP are 90%+ in agreement -- maybe that famous 'violent agreement' Me? I agree too.

 

[Kevin C Brown]

Actually, one of Lance's points rings very true. I don't disagree that a good quality bookshelf speaker integrated properly with a sub can provide a good alternative to a good tower speaker, but... In a lot of cases if you look at real world measurements, those little boxes that some manufacturers call "satellites" absolutely do NOT and are IMPOSSIBLE to integrate properly with the "subwoofer" they are bundled with simply because their low end extension does not meet up with the sub's upper end extension.

Plus. I am still saddened by the fact that most subs only come with a 0/180 deg phase switch, and not a variable phase knob. It is almost impossible to properly integrate speakers with a sub if you only have those 2 positions for phase. Yes, you can do tricks like adjusting the distance to the sub to account for the difference, but most people don't know that and wouldn't even know how to do it correctly even if they did.

IMO, some people think you can truly get something for nothing, but it just isn't true. I have an informal database of the cheapest HTIB that I've come across. The winner is one I saw advertised for today (a Black Friday sale): $59 for 5 satellites, a sub, and a DVD player/receiver combo. Now, just what kind of sound quality do you think will come out of a package like that?

I think Lance's point is that if you buy speakers with low enough extension in the first place, and no, I don't see him advocating towers all around, he simply mentioned a 6.5" woof driver as a typical minumum requirement for a speaker like that, that *then* you can run all large, sub on, and be happy enough.

 

[ChrisWiggles]

it's the running large that i have a problem with, coupled with the extremes of including very small sat-type systems which are not effective and I don't think should be part of a discussion about high quality audio.

 

[Dick Knisely]

Personally, I agree with you but quality is so subjective. I'm not a golden ears/eyeballs guy (to *&!@ old for one thing) and my stuff is very much a "good enough" situation but there are times when I'm at someone's house and they've got their TV and/or audio system on and I want so bad to crank the color & contrast down so my eyes don't hurt and adjust the audio so it doesn't give me a headache. But it is there "stuff" and they're apparently happy with it. That's why so much of this stuff sells well -- the market really doesn't seem to know what quality means. And they sure don't see/hear it in the typical store.

 

[ChrisWiggles]

Oh man, I've been in Sears and Circuit City and BB here in the middle of nowhere california cause that's all there is shopping for TVs for the relatives and I can't stand looking at these TVs. To me they all look just plain broken. :frowning: I told a really pushy and irritating salesman today as much...

'look how good this looks'

so I say: "well, this TV has a bad power supply problems so watch the geometry distort, it's clearly far to blue in grayscale and pushing red decoding to compensate, not to mention its *horrendously* over-saturated and the white point is set WAYY too high and I have no idea about black level retention or capability because I'm standing under a thousand watts of flourescent lights, so actually this set looks pretty darn horrible, unwatchable to my eyes, right now."

He was really being a dick, and flat out argumentative when I tried to temper some of his pushy nonsense he was pushing on the family members next to me who I was trying to explain things to. "no you NEED and HDMI signal DVI doesn't work for HD, blahblahblah no you NEED a brighter display blahblahablah you absolutely need at this LCD with better contrast (hah! right) blahblah what are rainbows? no this RP-dlp has 3 chips blahblah 16 million colors, more than a CRT can do blablahbullsh*t" I was really nice, and really patient and gentle for about twenty minutes, hoping it get the drift and go away, and then i'd had enough. I really wanted to just blurt out "no, EVERY one of these displays looks absolutely HORRENDOUS, leave us alone, we'll pick a set and I'll spend an hour or so making it watchable since you have no clue what a standard image is supposed to look like."

haven't been tv hunting in a long time. pissed me off.

 

[LanceJ]

my emphasis

Bingo!

BTW: I would still strongly recommend such a speaker philosophy even with the use of bass management. And if you've ever watched a 5" driver bounce around even with a xover of 100Hz (that's as low as my receiver's b.m. can go) and still not sound right at lower/conversational levels, you can see why.

 

[Dick Knisely]

LOL and, Chris, from the sound of it, it might just be even longer before repeating the experience!

Serious thread drift warning...
Interesting experience recently when we bought a 20" Toshiba LCD for the bedroom. Set it up, scanned the manual, figured out the controls and popped in the Video Essentials DVD to run a quick calibration. Worked thru the whole thing and ended up with settings that weren't seriously different from the "normal" mode built in! First time I've ever had a TV even in the same ballpark as a calibration, even if it was just a first approximation pass. Of course the set's delivered with "sports mode" active which is, indeed, way too bright, contrasty and color saturated. The third mode is "cinema" and the calibration I came up with is just about half way between normal and cinema. I did find it harder to use that DVD with the LCD than with any of the tubes I've done or a plasma and I may have messed something up but I could be quite a bit off and still not be out of the ballpark of the factory settings for everything except sharpness which had to come down significantly.

 

[ChrisWiggles]

in any case, setting up a consumer tv is a *lot* easier than a full day doing a CRT setup, which is nice

 

[Kevin C Brown]

Why? I remember the good old days. *No* one used subs. People had "stereo equipment" and were completely happy. All of the sudden a sub is required for multichannel music listening? Shoot, how many people in Britain are perfectly happy with their bookshelf Harbeth, Epos, Spendor, shoot: that famous BBC speaker everyone over there tried to emulate? LS-1/A or something?

I think (one of) Lance's point is that: don't knock it if you haven't tried it. You might actually get better sound quality by running all large than by introducing problems with trying to integrate a sub. This is *exactly* why I don't use the BM in my universal player anymore. Most universal players have poor BM for SACD and DVD-A. Certainly not the flexibility you get in a receiver or pre/pro.

 

[LanceJ]

Kevin: I found this excellent site dedicated to the LS3/5 a couple years ago: The Unofficial LS3/5a Support Site I spent almost two hours on it when I first found it.

BTW: when Stereophile reviewed this very accurate Mighty Mouse speaker, the writer realized that the probable reason this little speaker seems to have so much bass is because one of the complicated crossover's duties was to depress all the frequencies above the lower bass frequencies. This re-balances the speaker's overall output so those lower frequencies are at roughly the same level as the higher ones. Very cool! This neat trick helped the speaker meet the design goals the broadcast engineers asked for i.e. a very full sound from a very compact monitor that could sit on the bridge of the mixing console. The trade off was that it was quite inefficient but this wasn't a problem because its intended use did not require high sound levels.

************************************************** ********

As far as phase cancellation issues when running all sats large: phase issues between these speakers will only arise when two or more of them are reproducing the same bass signal. I haven't tested every title I own but this only seems to consistently happen with the front left/right mains......which can also occur with a stereo rig. But if there are surround mixes out there that use 2+ channels to reproduce the same signal, I'm not saying this won't cause phase problems-IF you're sitting in just the right location AND/OR all the speakers in relation to one another will cause that situation-but the effects of a crummy b.m. configuration could be much worse (i.e. the DV-563 scenario).

Also remember even if there is cancellation occurring from whatever cause, that doesn't mean TOTAL cancellation is happening. To do so would mean the out-of-phase sound waves would have to be perfectly aligned in the physical space of your listening room-or mathematically speaking: 1 + -1 = 0, and to do so would be quite rare IMO. It's could very easily be more like this: 1 + -.2 = .8, so you're still getting 80% of the bass heard in the studio. I'm only a "casual" audiophile so this last scenario doesn't really bother me.

And even if the speakers were positioned properly in relation to each other, the room itself can cause cancellation issues because of reflections that bounce back to the listener & interact with the waves that arrived directly from the speakers.

AAARRRRGGGGHH.

So unfortunately, there is no quick-n-tidy answer to this complicated issue since this is very much system dependent. My system sounds great in my room and where I am seated, but if I moved it to my buddy's home it could very well sound like cow poo.

I finally just gave up wringing my hands over this because I realized if I set everything to large and it sounded good to my EARS, then that is all that mattered. So I did just that and it did sound good, so that was the end of worrying about this issue for me. Surround music is too fun for me to allow possible problems to keep me from listening to it.

* my $350 Technics SA-DA8 (2001 model) has no problems operating all those set-to-large speakers in my room, even at levels I would never listen at continuously, and with no clipping as so many people keep worrying about.

** when I use certain DSP modes on my receiver, the rears also seem to reproduce most of the bass found in the front mains. But their signal is delayed-user variable from 10 milliseconds up to 100 milliseconds-and I would have to be sitting in juuuuust the right spot to be located where each speaker's sound waves totally cancel out each other (-1 + 1 = 0). And at 40 milliseconds, apparently I'm not!