This was posted on another forum.

http://surroundpro.com/2002/october/columns1.shtml

I was only able to skim over the article, but I'll make a couple comments.

I believe that for music only applications, the LFE channel more a liability than an advantage. It is also MONO.

There are very few instruments that go down in the range that truly need a dedicated LFE channel to reproduce them. It is worth noting that even if your main speakers have a nominal low frequency limit of something like 50Hz, as you increase the number of speakers to at least the three that is the front of a home theater setup, the bass response will be extended somewhat by mutual coupling of the woofers. The result is more bass output and a lower frequency limit than one speaker alone can produce. (I'm assuming here that the bass is in all three front channels, which it will be to a certain extent in an acoustic recording of something like an orchestra).

In any event, if the speakers are set to "small" then the bass will be routed to the subwoofer, which can reproduce the bass (although it will be mono bass).

For music masters that are intended for mixing into a film, there usually is an LFE track that usually has both redundant and/or 'synthesized' bass information. This "synthesized bass" is usually the normal bass that has been passed through a sub-harmonic synthesizer to create an octave below the real bass. By the way, the finished LFE track in film mixing is sometimes created by this same procedure, with a sub-harmonic synthesizer, usually made by DBX, augmenting the lowest octave of the sound effects, and as I said, some of the music.

If you have the "Superman" (the first installment) DVD that has the re-created soundtrack, there are selections from the score that are seperate from the film as bonus material. I mixed these in my studio in 5.0. I did not want to use an LFE channel because I wanted the music to be as un-corrupted as possible from the original masters I had. The mix of the music in the actual film does have music in the LFE, but it was synthesized on the dubbing stage and did not exist in the original masters

You may prefer one or the other of the mixes, but the one on the 5.0 tracks is more representative of what the original masters sounded like when I played them in my room.

By the way, and as a bit of trivia: The "Main Titles" music that takes place when the titles are sweeping off the screen was recorded on the original masters 1/4 tone flat! I can't for the life of me figure out why - all the other music cues were recorded at correct pitch. As a result of this, and to keep the music in the original sync as it was when the original film was mixed, I had to digitally speed up the master to make it match. The result of this is that the sound is somewhat strident and the timbre of the instruments is corrupted by a small amount.

All the rest of the score does not have this problem.

By the way, Sound & Vision did a feature article on this DVD in the June 2001 issue. I have a couple quotes in it and my picture is also in there (in case you need a new dartboard ) There are scans of the article here: It has 4 pages.

page 1

page 2

page 3

page 4


[This message has been edited by soundhound (edited January 28, 2003).]

this article interested me a few months ago when i was struggling with the current state of bass management technology.

it's a good example of one side of the confusion/debate that surrounds the subject.

i happen to believe the lfe channel is the most exciting and the most misused channel of all surround formats.

bass management, as it exists, doesn't work.

i've included this article in my recent patent application, along with many others on the subject.

i've invented a new bass management system that works, is simple to use, will allow producers to properly monitor surround mixes, will satisfy both the audiophile and the videophile and makes for a whole new world of possibilities.

one of the reasons i attended ces was to meet with sony's chief sacd hardware engineer. i met with several other engineers from companies that are building the harware for my system.

maybe someone here might want to give a prototype a spin in the near future. (maybe that lunatic who has 4-18's and 1kwatt of toob jooce)

part 2 of the article
http://www.ambisonic.net/bassmgt2.html
was more interesting to me, though i'm afraid mr. elen will soon have to write a new article
if he wants to stay current.

kevin c brown said something to me back in october in this forum on the subject and it all basically flashed into my head at that instant. i've spent countless hours since then writing the specs, designing the hardware, writing manuals, designing logos, assembling a parts supplier list, etc.,etc. it's getting interesting...stayed tuned.

I am sad. I wish I knew as much about sound reproduction as SH and BoB. You guys have degrees, and practical experience, and all I have is, a few test discs, a $35 Radio Shack sound level meter... and a keen desire to learn more!

Y'all know what ETF is? Basically, software that uses the cheap soundcards in PC to take freq response, impulse response, phase response, etc. I can now do in 5 sec what used to take me 20 min (i.e., plot my room's low freq response). Me so happy...

(One quick cool thing, as I just took my 1st set of measurements: the curves I got from EFT are pretty darn close to the graphs I got with a discrete test tone disc and the RS meter. I was surprised it was as close as it was.)

I keep toying around with the idea that I think some people have done, of somehow having a dedicate sub for LFE and info crossed over from the surrounds/rears/center channel, and then another sub to run my mains full range into, and use the sub's crossover to split the high passed signal back into the mains. (I'm still an 80% 2 channel music guy.) But it gets too complicated when I think about trying to get a system like that to work for digital CD/DD/DTS/etc vs analog SACD/DVD-A...


[This message has been edited by Kevin C Brown (edited January 29, 2003).]

So hound, ya wanna tell us which on is you so we know who to aim the darts at?

Jason

SH=Bob????

I'm the music editor.

I want to buy a PC based MLS system, they're reasonably cheap and can be very versatile. What is ETF/EFT (electronic funds transfer ? )

As far as BM goes, I'd just like a way to tie a SW to each channel or set of channels and then 'split and mix' LFE into all of them as well. I can do it with off the self parts - mixers, electronic crossovers, etc., so I guess I know what I want to do for Charlie HT 2.0 - everyone needs a project, right?

One good thing - this setup won't care if the source is analog or digital.

EDIT - BoB: Good luck with the Patent!

I know it's just a peice of paper, but there's something really neato about having actual inventions with your own name attached. Be sure to post when your IP is protected and you can disclose.

[This message has been edited by charlie (edited January 29, 2003).]

Bosso:

Great to hear you've come up with a good way to inject some sanity into the BassMismanagement problem.

As for me, I'm pretty satisfied with the current setup I have, which just treats the front left and rights as extremely full range speakers. No matter what I throw at them, the bass will come through in proper proportion, and in stereo, with the subs right next to the mains.

I do agree with that article that the current LFE is kind of a bad fit into the current reality of DVD-A and SACD formats. Personally, I don't see that it is a great idea to have a seperate channel for the bass anyway: would you want to put your tweeters in a seperate location from your main speakers? I know that this is a silly example, but in a way it points to the fundamental problem. The bass should be coming from the same physical space as the rest of the spectrum, and the best way to do this is to have full range speakers.

After all, in the two channel days, there wasn't a huge cry of agony that the bass was somehow insuffient with the speakers available at the time. I think a lot of the problem now is that the WAF would be prohibitive to 5 big speakers in the living room.

I think there really needs to be some universal solution that will work with the average home theater / multi-channel audio setup (there's no hope for crazies like myself). It sure would be nice if yours is that solution

After all, in the two channel days, there wasn't a huge cry of agony that the bass was somehow insuffient with the speakers available at the time. I think a lot of the problem now is that the WAF would be prohibitive to 5 big speakers in the living room.

What a 'nail on the head' observation!