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post #1 of 23 Old 09-04-2003, 01:32 PM - Thread Starter
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Search function is down due to high volume.

Those that use or have used multiple subs, were you happy with the sound and in what ways did it change the sound? Also what sub(s) did you use? I have been kicking the idea of having a front and rear sub.

Thanks,
Matt
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post #2 of 23 Old 09-04-2003, 04:54 PM
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I have a pair of SVS 16-46PC+s. At first I had them on each side of the front of the room but I've moved them to off to one side near the front. I like the sound better in this position, but the front was also ok, just not what I prefer.

Dual subs give much more bass than a single sub could. And depending upon the placement, you can get addition or substraction on the bass wave frequencies. If you put them front and rear, you'll have to be careful about dead spots and wave peaks and valleys. Probably will want to have them setup with different polarity as well.

I do believe there are some good articles on sub placement, including duals that give some mathematics about harmonics and room size.

Myron
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post #3 of 23 Old 09-04-2003, 07:11 PM
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I use two identical Yamaha YST-SW800 in the fronts and one YST-SW320 in the back. All my subs are attached to the line out and not RCA out. For the fronts, they are crossed over at 45Hz as the main speakers are floor standing towers. For the rear surround bookshelf I have the sub crossed at 90Hz. My speaker management for bass is set to MAIN and my rear is set to LARGE.

I am pretty happy with this setup.
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post #4 of 23 Old 09-04-2003, 10:35 PM
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Matt I use multiple subs and will never go back to one. If someone had a 6000 cubic foot (cf) room they would need two, or more subs to fill the room. If a room is smaller you may not need as many. Find cf by multiplying LxWxH.
Both Matthew Polk ( www.polkaudio.com see "Home Theater Handbook")and Russ Herschelmann ( see "Home Theatre:Essential Elements" CEDIA 1995) state that multiple subs placed asymmetrically help smooth out bass response, cancel standing waves and provide better dynamic range. Doug Osbourne, Directer of www.mkprofessional.com (my sub favorite) says stacking multiple subs in a corner help you "feel" bass more than merely a single sub. Adding a third sub would be for headroom. See it, hear it, FEEL it. Only with multiple subs.

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post #5 of 23 Old 09-05-2003, 06:56 AM
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Matt,

The work that R. Herschelmann does for his company, as well as that for SGHT, Home Theater, and others - is quite interesting; and there is a lot of useful information to be gleaned from his series in SGHT. Of similar interest is Todd Welti’s White Paper on single and multiple sub placement at Harmon International; click on “Full White Paper†to read the *.PDF. When you’re done with the above or even before, there are 6 other very interesting white papers to read there as well, not to mention a modeling program for resonances…

Similarly there is an excel spreadsheet at SGHT to calculate resonant modes for a given room.


Regards,
=AirCeej=
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post #6 of 23 Old 09-05-2003, 07:42 AM
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I have three in my HT. Two (10") of them are built in my mains (powerd) i run them large, full range, and the SVS 20-39PC+ handles LFE. The SVS is up front to the left of the room, once i phase them all in took some time but worth it. They sound incredible together, i can't see just having one sub in a HT now. IMO.

Tee

"Enjoy Movies & Music"

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post #7 of 23 Old 09-05-2003, 09:16 AM
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AirCeej, thanks for the informative links!

A veteran is someone who, wrote a blank check Made Payable to 'The USA, ' for an amount of 'up to and including their life.'
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post #8 of 23 Old 09-05-2003, 09:36 AM
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I had 2 subs, went to one for a while, now I am back to 2 again. I am using 2 polk PSW350 subs. After going back to 2 subs(with a new receiver, pioneer 45tx), it feels like I can't hear the bass as much, but I can feel it ALOT more. It's like the sub got quieter, but the air pressure went way up. Is that what is susposed to happen with 2 subs?
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post #9 of 23 Old 09-14-2003, 07:41 AM
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I just added a second pw-2200 to my set-up. I placed the second sub next to the existing one. I have a fairly large room which has a 15 ft. opening into another large room and all I can say about the performance of this set-up is holy crap!!!! I calibrated it with a rat shack meter then played a few scenes from Titan A.E., then I went to the other rooms in the house and picked up my wifes nick-nacks that had fallen from the wall shelves! It had displaced objects two rooms away! It would be hard to go back to just one sub.
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post #10 of 23 Old 09-14-2003, 11:47 AM - Thread Starter
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Thanks for all the great information.

I have a Martin Logan Depth and my local shop loaned me a second Depth to test with over the weekend. Still have more work to do about placement but I can see I will be joining the "Multi-Sub-Club".


Thanks again,
Matt
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post #11 of 23 Old 09-16-2003, 06:37 AM
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Hello all,

I placed this question originally in the receiver forum, but it might make sense here as well.

After having HT set-up for a year, I decided that the bass wasn't what it should be (wanted to feel it), so I went looking for another sub to add to my system. I have cheap, large speakers for my system, so my thought was to add a sub to the center or right/left speakers to add more bass to those channels and leave the other sub just for the LFE output.

I found that made an improvement to the bass, but I found by changing the subwoofer setting on my receiver from ON to PLUS made a bigger difference, but so did changing the speaker size in the receiver from LARGE to SMALL.

Now I am all confused. My thought was to have large speakers so that the subwoofer could be used only for LFE. Is this thinking wrong??? I thought that having a sub dedicated to just LFE would allow for the best low frequency results because the sub wouldn't be maxed trying to do all the bass sounds.

So the question is, what is better - having one sub and all bass going thru it, or mutiple subs - one for LFE and one or more for other channels? If it is better to have one sub, should you set the speakers to SMALL or the bass to PLUS? If you do two subs, should one be for LFE and the other used for L/R channels, or run the two subs on the LFE?

I guess another question is LFE output all it is cracked up to be. In other words, would setting the sub on the LEFT/RIGHT speakers produce the same low frequencies as an LFE output?

I know I have a bunch of questions, so hopefully others have thought the same and have worked thru it.

Thanks!
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post #12 of 23 Old 09-16-2003, 07:59 AM
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I'm a Buckeye fan too. I was born in Mansfield.
The Lexicon MC-12B prepro has outputs for a LFE, plus a Left and Right sub. Some people like bass iamging, some like to feel more bass. A third (used for headroom) may cause peaks and dips if not properly equalized and used in conjunction with a spectrum analyzer. But the bigger the drivers, the more power and the more voice coils involved would help you "feel" chest pounding, concert bass more. You really, really have to be careful using multiple subs. The placement and EQ has to be right on, or you will create wildly varying bass response on the different channels.
My idea on LFE is it is a electronic crossover. THX setting is 80Hz, Sony decoders set it to 100Hz. (The sub plays 80Hz and below only, the sat's play 80Hz and higher only) It is also known as Bass Management. I recommend using one, or more subwoofers in mono and implementing the Bass Management feature of your prepro, or receiver. (You do this by wiring the sub to the "sub", or "LFE" output jack and also setting the Sat's to small and the sub to ON. Plus sounds like it may be a 3, or 6 dB gain and is fine. This will result from even bass response from all six channels. Bass Management creates five, or seven full-range speakers with identical 20-20KHz response.
This article by a pro explains it in simplicity:
http://www.mkprofessional.com/bass_mgmt.html

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post #13 of 23 Old 09-16-2003, 12:25 PM
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hometheaterguy,

Thanks for response and link to the article. It seems to make sense what you and the article say. So in your opinion, it is better to send all bass below 80-100Hz to one subwoofer than it would be to have one sub for LFE and another to take care of bass from the L/R? If two subs are used, run them off the LFE with the receiver set to PLUS bass or speakers to SMALL?
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post #14 of 23 Old 09-16-2003, 12:47 PM
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No problem Buckeye fan. I feel that if you keep the frequencies to all subs below 80Hz it would make a better splice with the satellites. In this link:
http://www.hometheaterhifi.com/qa/qa2002/qa296.html
a 10.2 (.2 for dual subs, stereo bass) Tom Holman the THX guy has two symmetrically placed cabinets. Bass imaging. Since frequencies below 200Hz are difficult for humans to localize, it is best to keep subwoofers in the range. Back in the day large woofers in 2-way designs would play well up to 3000Hz. Today the sub/sat/bass management idea has lower distortion and made sub placement easier. Bass is omni-directional, not non-directional. It is always best to set your satellite speakers to small.

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post #15 of 23 Old 09-16-2003, 02:34 PM
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Quote:
Originally posted by buckeyes fan
hometheaterguy,

Thanks for response and link to the article. It seems to make sense what you and the article say. So in your opinion, it is better to send all bass below 80-100Hz to one subwoofer than it would be to have one sub for LFE and another to take care of bass from the L/R?
I dissent.

It is absolutely better to use 1 sub system for dedicated LFE and another for redirected bass, because:

1. Each sub has considerably less stress.

2. The LFE can be volume adjusted to taste without distorting the redirected bass volume.

3. Intermod distortion is reduced.

4. The RB sub can be properly crossed with the mains for correct reintegration of redirected bass, while the LFE sub can be filtered to retain all of the LFE signal, or crossed to it's own sat for full range capability of the .1 channel with DVD-A/SACD formats.

5. A so called 'music' sub can peacefully coexist with a so called 'movie' sub in the same MC system.

The Lex MC12 is the only pre/pro available that lets you do this with a stock configuration (with the added plus of stereo RB subs, if you like that sort of thing), but virtually any system can be configured to acheive similar results by:

1. Connect the player's analog SW out to the LFE sub directly (you may need a preamp to boost the signal. A $70 mic pre will do the job).

2. Configure the player's setup as sub on and speakers large.

3. Connect the pre/receiver SW out to the RB sub.

4. Configure the pre/receiver setup to sub yes and speakers small.

Only RB will be sent through the pre/receiver SW out because no LFE ever went in. You'll have to adjust the LFE volume manually.

Why manufacturers don't offer the I/O choice with a sum option baffles me. It would cost next to nothing to implement.

IMHO, YMMV, etc., etc., but, FWIW, I've spent a year exhaustively comparing this setup to the summed single bass signal system and the numbers and listening tests do more than suggest the advantages are real.
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post #16 of 23 Old 09-16-2003, 08:58 PM
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Bossobass:

When you say "players analog SW out" are you referring to multi-channel out on SACD/DVA ??? What other players have analog SW out ???

"What happens in Vegas..."
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post #17 of 23 Old 09-16-2003, 09:15 PM
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What exactly is the definition of "redirected bass"?

I have an MC-12 and am trying to determine the best set up for my speakers. I have NHT VT-3 system with the two main speakers having a range down to 20hz with two built in 10" woofers and 500w amps in each L and R speaker. My remaining speakers are satelites (VC-3 VS-3) with a range to 40hz.

I also have two 18" Subs (Velo and Triad). I have been using the subs in a stereo config but am considering the Mono and LFE options.

Should I run my main VT-3's full range or cut them off at 80hz and send the lower frequencies to the subs? Should I use the two subs just as LFE and the main speakers full range? What about the Surrounds and center, if I am using the subs as just LFE, where do I send the lower frequencies from my Surrounds and Center?

Anyone who has any thoughts, please chime in here.

Thanks,

Phil
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post #18 of 23 Old 09-16-2003, 10:11 PM
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Phil, Dolby, DTS, M&K Professional, Polk and many others agree on setting your satelittes to small so they only play 80Hz and up. L, C, R, and surrounds. You could run the 18s in mono daisy-chained in the LFE output. It is not recomended playing the mains full-range in home theater. I recommend using one, or more subwoofers in mono (bass is recording on the left channel-mono) and implementing the Bass Management feature of your prepro, or receiver. This will result from even bass response from all six channels. Bass Management creates five, or seven full-range speakers with identical 20-20KHz response.

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post #19 of 23 Old 09-17-2003, 06:48 AM
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That makes sense. It just seems like a waste of the VT-3's which are basically satelites incorporated into a cabinet with two dual 10" woofers with built in 500w amps. If I just use the 18" subs, I would be effectively turning off the two additional subs built into my L and R speakers.

Phil
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post #20 of 23 Old 09-17-2003, 07:17 AM
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This is an interesting thread that is running along with the one in audio theory. Why do these speaker companies come out with these type of speakers that have integrated bass modules when they are not effective for multi-channel systems? As Phil said, it seems a waste, but they are really popular.
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post #21 of 23 Old 09-17-2003, 11:02 AM
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JR,
Yes, the term MC (multi-channel) system implies inclusion of DVD-A/SACD formats. I apologize for being vague.

Free,
Redirected bass (Lex refers to it as 'derived bass') is bass that is redirected from speakers set to 'small' to another speaker (usually a sub).

When any speaker is set to 'small', the pre/pro or receiver creates a duplicate signal. One signal is high pass filtered and sent to the 'small' speaker, the other signal is sent to the sub where it is low pass filtered and summed with the LFE signal to create 'a single digital bass signal'.

Some chipsets allow the full LFE signal (a global 120 Hz LP filter) to be summed with the redirected bass which is LP filtered according to the crossover point selected for speakers that are set to 'small'.

The Lex MC12 has the best I/O options of any pre/pro I know of. It has 'Bass Enhance', which is a matix of stereo redirected bass (requires 2 subs) that uses phase shifting to sonically add spaciousness to the LF (as opposed to it sounding like it's centered in your head).

You can use 1 sub for discrete LFE and another for discrete redirected bass (the best MC low freq option, hands down, to me).

You can also run stereo subs and a discrete LFE sub (3 subs).

The MC12 also has time delay for subs. Time arrival of the direct radiated sound is the most important thing to accomplish with multiple subs. Without time delay option, equidistant placement is necessary. This is why there are so many placement theories with multi-subs.

Large mains and/or sats is not usually very effective because with those speakers you have no placement option. They have to be critically placed in relation to the listening position, whereas subs can be tweaked as to placement for best bass response in a given room at the LP.
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post #22 of 23 Old 09-17-2003, 04:47 PM
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Quote:
Originally posted by Randybes
This is an interesting thread that is running along with the one in audio theory. Why do these speaker companies come out with these type of speakers that have integrated bass modules when they are not effective for multi-channel systems? As Phil said, it seems a waste, but they are really popular.
I would say that they are perhaps trying to duplicate something like these:
http://gallery.avsforum.com/showphot...t=1&thecat=500

While I haven't necessarily heard the speakers to which you are referring, I most certainly will say that mine are effective for multi-channel.

As for them being really popular, that would probably be why they are coming out with them. The consumer determines what will be produced by buying more of what they want and less of what they don't want.
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post #23 of 23 Old 09-17-2003, 05:10 PM
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Quote:
Originally posted by Mr.Poindexter
I would say that they are perhaps trying to duplicate something like these:
http://gallery.avsforum.com/showphot...t=1&thecat=500

While I haven't necessarily heard the speakers to which you are referring, I most certainly will say that mine are effective for multi-channel.

As for them being really popular, that would probably be why they are coming out with them. The consumer determines what will be produced by buying more of what they want and less of what they don't want.
Wow, that looks like a "perfect storm: Incredible!
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