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So I initially I was getting ready to buy a SVS SB13U. Then I started reading articles etc. Is it worth it to run 2 subs for music purposes? These articles left me hanging if I should go with 2 cheaper subs... :confused:
 

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There is no Stereo Bass. Its only mono. But with 2 subs you will smooth out the FR. With one sub, there is usually peaks or nulls somewhere in the FR. With 2, it can smooth out the response.

Here is an example of a graph that shows the smoothing. The bottom 2 lines are sub 1 and sub 2. You will notice one sub has a big null (loss of sound) at 60 Hz. And the other sub is peak about the same FR.
Now look at the top 2 lines ( I turned up the volume just a little to seperate the lines ). Those are with both subs playing together. You will notice the peak and the null of each sub at 60 Hz completely gone.
 

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For all intents and purposes, it is accurate. For example, a 50 Hz note has a wavelength 22 ft long. Way too long to provide any localizable stereo cues or information.
Oh, you didn't read the linked thread.

Bass is not just 50 Hz.
 

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Typical bass management is going to redirect bass from both the stereo channels to the subwoofers. You would not be "losing" any information.

Having the bass come out in "stereo" where each of the main speaker locations is not providing a linear in room response and would not be as good.
 

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fwiw,my understanding is that as long as what goes to the sub or subs is below the frequency range that you can localize (80 Hz crossover seems to be widely accepted), then having, say, the 80 Hz and below frequencies from cellos and basses coming from the right side while the 80 Hz and below sound from the percussion section comes from the left side will be indistinguishable from the more typical approach to mix all that redirected bass to a mono channel and send that to the subs. Drums, cellos and basses can of course be localized, but that comes from higher harmonics. The crossover just sends those lower frequencies to the sub, not the whole sound of the note. So Charlie Haden playing an open low E at roughly 40 Hz will be reproduced by the 40 Hz and 80 Hz components of the note (first and second harmonic) going to the sub (it's not a brickwall cutoff, but essentially . . .) while the 120 Hz, 160 Hz, 200 Hz, 240 Hz, 280 Hz, 320Hz, etc. harmonics of that note don't go to the sub (at least not so much) but to whichever speaker(s) capture the placement of the stereo field where the bass was mixed. AIUI as long as your head isn't many feet wide, the wavelengths of the lower frequency components will not induce a sense of directionality, onaccounta how human hearing works. And you'll still hear Mr Haden in his proper location whether redirected bass is mono or stereo.

In olden days, it was, supposedly, typical to take the bass to mono for vinyl reproduction so you were spreading out the pain and or inaccuracies of the tracking devices, to allow stronger bass reproduction. Might be done less in digital. the reason to to reproduce differential bass in house sized rooms is it potentially complicates the process of trying to pressurize the room evenly, without providing any audible benefit (as long as the crossover is low enough - a 125 Hz crossover is (a) a fifth above the lowest note on a normally tuned guitar [fifth string second fret B - which is still well within the bass pattern playing range of a bass guitar, although I'd take either side of the argument whether it's really a bass note. When you go upthe neck on the skinny string of a bass you get right into the range of a flute at about 250 Hz. the fact that a bass can play the note doesn't make it really a bass note, and if a person played a bass part all in that top octave between 125 and 250 Hz (ish) most of us would wonder where the bass was. OTOH, using those notes for color, or for solos or as part of a chord on the bass can be very musically satisfying. It just won't make your significant other shake his or her behind . . .
 

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I think it mostly will come down to the AVR/Pre-amp/Reciever! My Marantz has dual sub outputs and will level and delay each sub separately. But its not 2 channels. That is why its called 7.1. If you had a 7.2 then it should be stereo. But then finding source that is stereo for .2 is another story.
As far as just listening to 2 channel stereo, I still think you would need to look at the hardware and see if it supports dual channel LFE. I suppose if your reciever has channel A and channel B and if you can run both channels at once and hooked your subs into the speaker outs and used the crossover on the sub itself, then you would have stereo sub. But coming out of the sub LFE outputs, I think most you will find is mono.
 

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So I initially I was getting ready to buy a SVS SB13U. Then I started reading articles etc. Is it worth it to run 2 subs for music purposes? These articles left me hanging if I should go with 2 cheaper subs... :confused:
Can you give a little more info on what you are interested in pursuing?

I think it mostly will come down to the AVR/Pre-amp/Reciever! My Marantz has dual sub outputs and will level and delay each sub separately. But its not 2 channels. That is why its called 7.1. If you had a 7.2 then it should be stereo. But then finding source that is stereo for .2 is another story.
As far as just listening to 2 channel stereo, I still think you would need to look at the hardware and see if it supports dual channel LFE. I suppose if your reciever has channel A and channel B and if you can run both channels at once and hooked your subs into the speaker outs and used the crossover on the sub itself, then you would have stereo sub. But coming out of the sub LFE outputs, I think most you will find is mono.
I'm not sure I follow, but LFE is .1 whereas stereo is 2.0 -- no?

If you are discussing sources for stereo bass, the link I dropped has some examples.
 

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Discussion Starter · #11 ·
Can you give a little more info on what you are interested in pursuing?



I'm not sure I follow, but LFE is .1 whereas stereo is 2.0 -- no?

If you are discussing sources for stereo bass, the link I dropped has some examples.
I think I'm just going to stick with the SB13U. My room is only 14x12x8. I don't have much room to put 2 and for them to be optimal. I was just trying to find someone's expereince with it. If they got better SQ from this stereo bass.
 

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You may get better responses in the "2-Channel Audio" subforum. http://www.avsforum.com/forum/173-2-channel-audio/

Really what you are asking about is creating true full range speakers for your L and R by supplementing your speakers with a sub at each channel. The proper way to implement this is to not use the sub/LFE output of your AVR/prepro, but instead to basically create an active crossover system (albeit just for bass management) by feeding the L & R channel preamp signals to the respective subs along with the main speakers. You can achieve this in different ways depending on the specifics of your system. If you are also using the system for HT use, then it becomes more complicated, unless you get a third sub to handle the ".1" LFE duties.
 

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It really is not worth pursuing. Most directional cues will be above the sub passband and handle by the mains. You will hear occasional sound ques with stereo bass but, in my experience it is not better. Most bass is recorded in a mono channel. Stereo bass would make the needle jump out of the groove playing records.
 

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Oh, you didn't read the linked thread.
Bass is not just 50 Hz.
No, but for the last 40 odd years all of the information in the bass range, 100Hz and lower, has been summed to mono in the mixing process. It's been that long since recording engineers and producers recognized that there was no point to stereo bass, so they stopped doing it.
 

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Can you give a little more info on what you are interested in pursuing?



I'm not sure I follow, but LFE is .1 whereas stereo is 2.0 -- no?

If you are discussing sources for stereo bass, the link I dropped has some examples.
There is some newer AVR's prepro's that has 7.2, meaning 2 LFE channels. Like some of the the Denon models.

The ".2" indicates the 7.2 receiver's support for two specialized channels that handle only very low frequencies – otherwise known as Low Frequency Effects or LFE – which are output to specialized speakers called subwoofers. For a large room (or for users who love deep bass effects from their movies or games), the two LFE channels a 7.2 receiver provides are more potent than the one LFE channel that you get with a 7.1 channel receiver or 5.1 receiver.

NOTE: It does not say the channels are stereo. It just says it has 2 channels. My Marantz also has dual sub outputs, but its classified as a 7.1.. So this can be misleading and confusing.
I am with Bill, and I remember reading this in a article somewhere not to long ago. Which is why I posted at the top that there is no Stereo Bass. Meaning bass (LFR) that subs normally play in.
I wasnt talking about upper bass FR that normally don't play thru your sub and you can get from your L/R.
 

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No, but for the last 40 odd years all of the information in the bass range, 100Hz and lower, has been summed to mono in the mixing process. It's been that long since recording engineers and producers recognized that there was no point to stereo bass, so they stopped doing it.
The statement was made that there is "no stereo bass", which is not accurate if I understand correctly. Your comment that the mixing process changed around 1975 would seem to indicate that you agree with me. I'm not advocating either way and it's above my pay grade to opine if there is a point to it or not, so I will just take your word for it.

Here's another thread that was pretty interesting:

http://www.avsforum.com/forum/91-audio-theory-setup-chat/1113793-spatial-bass-real-not.html
 

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I found the article on stereo Bass? http://www.soundoctor.com/whitepapers/subs.htm

STEREO BASS?
Oh, and to touch upon "stereo bass" for a moment... there almost is no such thing. Going back to vinyl, every stereo record cut in the last 60 years has mono bass. It has to. If the bass were 180 degrees out of phase L and R then there would be vertical modulation and the stylus would jump out of the groove. Therefore every cutting lathe on the planet has a "compatalyzer" circuit, that dumps frequencies below 160 hz into mono (typically a single-order filter, therefore 6dB/octave). You MAY have out of phase bass (i.e. "low frequencies") on a CD, but precious few producers/engineers are savvy enough (or care enough to even bother, since what's the point?) to make use of those sort of tricks. There are some trance / psychedelia / electronica dance music releases where there are bass tracks where there is stereo bass in the form of something like 24 Hz in one channel and 24.2 Hz in the other channel; therefore you get an air pressure differential which travels around the room. Cool! In the above example, the "traveling wave" would take 5 seconds to go back and forth around the room. If you're a really bored or obsessive techweenie you can have a lot of fun with this - we played with this phenomena at Moog Synthesizer as far back as 1969. As far as PLAYING BACK signals like this goes, as mentioned above, in a large theater or outdoors you CAN have multiple bass sources of differing phase because there are no standing waves, and so your ears (and indeed your whole receptive system) can process and differentiate all the phase issues. In a much smaller room like a living room, it is more difficult but you might be able to pull it off if your subs were more nearfield (the pressure zone). If you invent something new, let me know. Bass is fun!
 

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Don't know what you guys mean by "stereo bass,", but in a dual sub arrangement, instead of 7.2 (two identical LFE channels output to subs from the AVR with bass management in the AVR), you can route Front L and Front R through each of two identical subs with their crossovers set the same, and you now have the discrete LFE from each channel being played from the subs.[1]

Is it localizable? Not if the crossover is below say 100Hz. But in this arrangement you can have the subs' low-pass crossover set higher (200Hz) so that smaller FL and FR speakers (i.e. bookshelf size) can operate more efficiently, and the bottom of the localizable bass is separated left to right (depending upon placement of the subs). In this setup, though, you're kind of limited in sub placement; ought not to set one by the display (center), and one behind the MLP.

Just my two cents, based on Richard Hardesty's sub fundamentals series at Widescreen Review).

[1] Actually, I don't know what "7.2" refers to ... dual, identical LFE channels, or two discrete sub channels to handle the FL+SL and FR+SR bass energy? In discrete, whch gets the Center and SBL+SBR LFE, either, or both? Not really germane to this discussion.....

// Posted from Tapatalk 3.2.1 for iOS - later versions are pfft //
 

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Usually a system claiming to be .2 routes the same LFE signal to both LFE channels but includes Audyssey SubEQ that first compensates for any level and delay differences between two subwoofers before applying Audyssey MultEQ® XT 32 to both subwoofers together.


No, it means 2 subwoofer outputs. LFE channels are in the source material and all source material so far has a maximum of one LFE channel.
There is some newer AVR's prepro's that has 7.2, meaning 2 LFE channels. Like some of the the Denon models.

The ".2" indicates the 7.2 receiver's support for two specialized channels that handle only very low frequencies – otherwise known as Low Frequency Effects or LFE – which are output to specialized speakers called subwoofers. For a large room (or for users who love deep bass effects from their movies or games), the two LFE channels a 7.2 receiver provides are more potent than the one LFE channel that you get with a 7.1 channel receiver or 5.1 receiver.

NOTE: It does not say the channels are stereo. It just says it has 2 channels. My Marantz also has dual sub outputs, but its classified as a 7.1.. So this can be misleading and confusing.
I am with Bill, and I remember reading this in a article somewhere not to long ago. Which is why I posted at the top that there is no Stereo Bass. Meaning bass (LFR) that subs normally play in.
I wasnt talking about upper bass FR that normally don't play thru your sub and you can get from your L/R.
 
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