Adding subwoofer to center channel - Page 2 - AVS Forum
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post #31 of 43 Old 03-01-2010, 12:44 PM - Thread Starter
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Quote:
Originally Posted by lennon_68 View Post

That's what's most important, you've tried it both ways and prefer it the way you have it, nothing wrong with that! I'm just not sold, especially not based on the reasons given

Your point was (I think, correct me if I'm wrong) that you wouldn't want to sum them and boost as that will be overpowering, I was just saying that it's not much different than running the one sub signal with LFE+redirected bass but not as hot to avoid the overpowering, bloated sound.

Say you like to run your LFE 6dB hot and are running your subs with bass management on for all speakers so LFE+redirected bass. If there's a special effect on the LFE channel and the same special effect at the same level on the center channel your AVR will sum these for +3dB + your 6dB boost. If you ran separate subs for each channel and only ran the LFE sub 6dB hot but ran the sub for the CC flat then you would get +6dB on the LFE signal and something more like +.5dB from the small addition that the center channel dedicated sub is producing (since it's 6dB lower in level than the LFE sub - so basically it's not contributing much of anything to what you're hearing). If you run all subs off of LFE+redirected bass and only ran them 3.5dB hot the end result would have been the same as running the two separate but now each sub is pushing the same signal so the LFE sub isn't doing all of the heavy lifting while the CC dedicated sub does very little and contributes practically nothing to the resulting effect.

Also if you only run the LFE sub hot and there's a LFE event on only the front or center speakers it will sound like a much smaller event than those that are on the dedicated LFE track in the same movie.

I understand your point of view and perhaps there is something of an issue if there is a combined event...but on otherhand if the it is an event only on center, should have no problem since there is no LFE summing issue? My experience with front l/r has been that it was not over powered by lfe, have to try center to see if there is an issue...Thanks for your thoughts!
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post #32 of 43 Old 03-01-2010, 12:45 PM
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Quote:
Originally Posted by Zmaximus View Post

I have tried all this and ended up an easier way...I run the rca out to sub, run SMS (for live feedback only) to fine tune the phase, crossover and volume and then let Audyssey do its thing..comes up pretty flat. I gave up on adding more things in line, system sounded more compressed to me. I dont run the sub portion hot, just enough to lift up low freq curve. My front three are being run by monoblocks anyway, tried the active crossover and caused more problems then simply mixing in dedicated sub for low freq.

I'm not sure I understand what you're trying to accomplish then. You want to add a sub to the center channel signal but don't want to use a crossover to do so? So you're going to run the speaker full range plus use a sub with it? You just need to split off the signal then and use the LP filter on the subwoofer to do that. I must be missing something.
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post #33 of 43 Old 03-01-2010, 12:47 PM - Thread Starter
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Originally Posted by lennon_68 View Post

I'm not sure I understand what you're trying to accomplish then. You want to add a sub to the center channel signal but don't want to use a crossover to do so? So you're going to run the speaker full range plus use a sub with it? You just need to split off the signal then and use the LP filter on the subwoofer to do that. I must be missing something.

Precisely! This is exactly what I plan to and have done with frnt l/r. My initial question was will adding a sub to center make sound presentation better?
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post #34 of 43 Old 03-01-2010, 01:00 PM
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Quote:
Originally Posted by Zmaximus View Post

Precisely! This is exactly what I plan to and have done with frnt l/r. My initial question was will adding a sub to center make sound presentation better?

My apologies, I read the question was "how do I" when it was actually "should I" (I see that now that I re-read the OP)

As you can see the topic is somewhat "controversial" - definitely polarized. For me personally the theory points to "not necessary" but the best way to find out will be to try it and see. It sounds like you enjoy the effect adding a subwoofer to the L&R gave you so I think it's save to assume, by extension, that you will get more enjoyment out of adding a subwoofer to the center as well
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post #35 of 43 Old 03-01-2010, 05:12 PM
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I did this very thing with my system with fantastic results. But realize my situation is very unique. I have a very odd shaped room which created some bizarre null voids. If i place my SVS sub in the front of the room bass was lacking in back, if placed in back then bass would be missing up front, and because of the odd room, placement was limited.

So I moved my SVS PB12 NSD/2 to the back of the room nearfield and bought some DefTech BP7001 towers up front (when set to large the bass was too muddy, so I crossed than at 40Hz and the bass tightened right up) Well then a strange thing happened my DefTech LCR2002 which is doing alright couldnt keep up with the bass of the towers so when a plane would cross from left to right it would sound like BBBBBBBBbbbbbbbbbbbBBBBBBBB. It's not the sound was too hindered it was the bass extension of the center (crossed at 70Hz) couldnt match the 10" drivers in the towers and handle 40Hz.

So I thought what I could do because I didn't want to toss out or sell at a reduced price my beloved LCR2002 and din't want to buy the uber expensive LCR3000 just to get deeper bass. So my local Utimate Electronics had a sale on Deftech Prosub 800 for 215.00 brand new. and I knew it could stay steady down to 38Hz, so it would easily match my towers crossed at 40Hz, so I bought the Prosub and have it hooked up just to my center. The results were quite surprising, bass was now very fluid, no null voids (in the center) and I was very surprised at how much bass actually is coming directly from the center.

Granted calibrating is very tricky to get that perfect blend, but I now have bass (down to 40Hz) all along the front and since most movies are mixed with bass from 30-100Hz, it does just fine and the sub handles the real low end of all the channels. I have tested many bass heavy movies, U-571, Cloverfield, Transformers and so on and now have that bass effect that I have heard many times in HT systems costing many tens of thousands and I beat out my local cineplex with deep clean bass and since my sub is near field, I also get that "tactile effect".

Now I wouldnt recommend this for everyone, but if you find your bass is lacking when compared to your mains, then a simple sub may help with that deep bass, while leaving the mid range to handle just that. The mid range 100-120Hz and up.

In fact Chet at DT commented that by using the lesser center with the 5.25" drivers instead of the 6.5" drivers that the mid range would be "tighter" and since my center sub handles everything from 40-100Hz and the SVS on anything below 40Hz, I get that clean bass up front and that non directional powerful bass in the back and it creates an overwhelming effect of bass from all over.

I say go for it.
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post #36 of 43 Old 03-01-2010, 06:25 PM - Thread Starter
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Quote:
Originally Posted by UofAZ1 View Post

I did this very thing with my system with fantastic results. But realize my situation is very unique. I have a very odd shaped room which created some bizarre null voids. If i place my SVS sub in the front of the room bass was lacking in back, if placed in back then bass would be missing up front, and because of the odd room, placement was limited.

So I moved my SVS PB12 NSD/2 to the back of the room nearfield and bought some DefTech BP7001 towers up front (when set to large the bass was too muddy, so I crossed than at 40Hz and the bass tightened right up) Well then a strange thing happened my DefTech LCR2002 which is doing alright couldnt keep up with the bass of the towers so when a plane would cross from left to right it would sound like BBBBBBBBbbbbbbbbbbbBBBBBBBB. It's not the sound was too hindered it was the bass extension of the center (crossed at 70Hz) couldnt match the 10" drivers in the towers and handle 40Hz.

So I thought what I could do because I didn't want to toss out or sell at a reduced price my beloved LCR2002 and din't want to buy the uber expensive LCR3000 just to get deeper bass. So my local Utimate Electronics had a sale on Deftech Prosub 800 for 215.00 brand new. and I knew it could stay steady down to 38Hz, so it would easily match my towers crossed at 40Hz, so I bought the Prosub and have it hooked up just to my center. The results were quite surprising, bass was now very fluid, no null voids (in the center) and I was very surprised at how much bass actually is coming directly from the center.

Granted calibrating is very tricky to get that perfect blend, but I now have bass (down to 40Hz) all along the front and since most movies are mixed with bass from 30-100Hz, it does just fine and the sub handles the real low end of all the channels. I have tested many bass heavy movies, U-571, Cloverfield, Transformers and so on and now have that bass effect that I have heard many times in HT systems costing many tens of thousands and I beat out my local cineplex with deep clean bass and since my sub is near field, I also get that "tactile effect".

Now I wouldnt recommend this for everyone, but if you find your bass is lacking when compared to your mains, then a simple sub may help with that deep bass, while leaving the mid range to handle just that. The mid range 100-120Hz and up.

In fact Chet at DT commented that by using the lesser center with the 5.25" drivers instead of the 6.5" drivers that the mid range would be "tighter" and since my center sub handles everything from 40-100Hz and the SVS on anything below 40Hz, I get that clean bass up front and that non directional powerful bass in the back and it creates an overwhelming effect of bass from all over.

I say go for it.

Appreciate you sharing your experience! and am going for it Actually, Aerial Acoustics have an extra large center channel CC5 and was trying to avoid that fill out the bottom with a sub instead and your experience is pretty much in line to what I am going through!
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post #37 of 43 Old 04-07-2012, 11:39 AM
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Zombie thread!

I just did this with my center channel, so I thought I'd add my experience to the mix (...as it were...).

The way I have it set up is as follows:

--- Receiver ---

Onkyo TX-NR807 CC speaker-out (xover at 40hz) -->

--- Sub ---

Mirage LF-100 (right) speaker-in -->

Mirage LF-100 (right) speaker-out -->

--- Center Speaker ---

Mirage OMD-C1 I'm still tweaking the sub's level and crossover settings, but right now it's at about 60% level, and I have it sending frequencies over 90hz to the OMD-C1.

I really like the result. I'm running the system without a sub right now, but telling the AVR it has one, so that it will allow me to set the fronts as not "full range" -- which they aren't, and so would possibly damage them to send that signal.

It lacks the gut-rumble that a sub would obviously provide, but it definitely has that nice "mid-bass" impact that the Center/Fronts were lacking, being bookshelves. I recommend it if you have highs-leaning speakers, and an extra sub laying around.

One question: Should I keep the sub paired to the center channel, or should I pair it to the L&R speakers (it has left and right I/Os). Related, should I "bi-amp" the center, and have the sub's L&R outs both go to it; or should I leave it with only the right channel in and out?
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post #38 of 43 Old 04-07-2012, 12:08 PM
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Originally Posted by Oroboros View Post

.............and I have it sending frequencies over 90hz to the OMD-C1.

How? Does the sub high-pass its speaker-level outputs at 90Hz? The sub's low-pass setting (it's NOT a crossover) will not affect what is sent to the speaker outputs. Those speaker outputs are either high-passed at a fixed value, usually 80 to 120Hz or so, or they are simply pass-through outputs.

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post #39 of 43 Old 04-07-2012, 01:21 PM
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According to the manual, the speaker I/Os are "High Level." It doesn't go into much more detail than that. It does say, though, that:

"[the] rotary control adjusts the high frequency roll-off of the subwoofer."

So, perhaps it's more accurate to say that I'm telling the sub to play everything 90Hz and lower, vs. the speaker playing 90Hz and higher.

The speaker is, as you say, probably getting a fixed high-pass of unknown value -- though I imagine it's close to 90Hz-100Hz, given that it sounds best with the sub's roll-off in that range.

Thanks for the clarification!

ETA: Is there any way to find out/test what frequency the sub is sending to the speaker?
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post #40 of 43 Old 04-07-2012, 03:58 PM
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Quote:
Originally Posted by otk View Post

wouldn't have it any other way. i have bass management. it came free with my receiver. i don't like what it does to the sound. it actually destroys the sound quality IMO. if bass management sounded better, i would surely keep it turned on

it's really hard to put into words. you just have to experience it

I feel the same way. I bought Def Tech speakers with built in powered subs for my entire system and cross them all at 50hz. I enjoy the more localized midbass and the overall sound i get from doing this. I think i would really like the sound of true full range sound from every channel but am perfectly happy with what i have. So happy that i cannot justify spending the money it would take to get there.
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post #41 of 43 Old 04-16-2012, 06:44 PM
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So, I emailed Mirage regarding the high-pass specs, and they were nice enough to get back to me:

Quote:


Quote:


Hello,

I'm wondering if y'all can tell me what frequency the High Level outputs on the Mirage LF-100 subwoofer pass to a speaker connected to them.

Thanks!

Hi [Oroboros],
Unfortunately we do not have any documentation on this series sub to offer the crossover point
I looked through the owner’s manual and there is no mention of the frequency
It may be 80 to 85 Hz, that info was from the BPS-150 and BPS-100 manufactured prior to the LF-100
From subs of that period that could have been between 80 to 120 Hz.

Klipsch bought Mirage in 2006 and from all the information we have, the LF-100 does not offer the frequency point

___________________________

Steve [Redacted]
___________________________________
Klipsch Group, Inc. Klipsch | Jamo | Mirage | Energy
3502 Woodview Trace, Indianapolis, IN 46268

Sadly, this doesn't give me much to go on, but I thought I'd share.
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post #42 of 43 Old 04-16-2012, 06:57 PM
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Also, bump for this:

Quote:


One question: Should I keep the sub paired to the center channel, or should I pair it to the L&R speakers (it has left and right I/Os). Related, should I "bi-amp" the center, and have the sub's L&R outs both go to it; or should I leave it with only the right channel in and out?

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post #43 of 43 Old 04-17-2012, 08:18 AM
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Quote:
Originally Posted by Oroboros View Post

Should I keep the sub paired to the center channel, or should I pair it to the L&R speakers (it has left and right I/Os).

That's up to you. Why do you want to add a sub to either of those? Do you just have an extra sub lying around? Remind us what it is. And remind us what your front and center speakers are. And what is your "regular" sub?


Quote:
Originally Posted by Oroboros View Post

....should I "bi-amp" the center, and have the sub's L&R outs both go to it; or should I leave it with only the right channel in and out?

Do you mean bi-wire? Or bi-amp? Do you have two amps connected for your center channel? If you mean bi-wiring the center channel off of one amp channel, through the sub, there is no more of an advantage to doing this than bi-wiring the center speaker directly. The sub will work fine with only one channel of input.

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