I'd like to run 4 subs in my HT setup. Right now I have 2 running off of one LFE channel (split once). Call me crazy but to me it seems like theres a noticeable difference in the gain needed from two subs as opposed to when the lfe is just running into one sub. I’ve read (somewhere I can’t remember) that splitting the LFE shouldn’t make a discernable difference when splitting it no matter how many times? The statement “no matter how many times” didn’t make sense to me either because there’s got to be signal degradation at some point (like I may be experiencing) right? Anyway I’ve seen a lot of people having 4 or more subs and was wondering if there’s a way around the signal degradation besides compensating for it by turning the volume up on the sub, or is it just something that I’m going to have to deal with.
It’s a Denon 3310ci and right now I’m running a mirage SS-1000 and SS-1500. I’d like to add in 2 BPS-400’s to top it off.
Thanks in advance!
It’s a Denon 3310ci and right now I’m running a mirage SS-1000 and SS-1500. I’d like to add in 2 BPS-400’s to top it off.
Thanks in advance!
Yes if you Y the signal it can cause a small reduction in signal level. Room modes are probably the issue. Could be that they are placed incorrectly. Got a mic? Use Room Equalization Wizard (REW, it's free).
You can simulate your room/speaker/sub placement in REW without a mic, but is only a guesstimate.
You can simulate your room/speaker/sub placement in REW without a mic, but is only a guesstimate.
If you are using the low level(RCA) output from the Denon and splitting it to the low level(RCA) inputs of the sub amps that you are using (and they are the typical 100k+ ohm input impedance), you shouldn't notice any level degradation even with 4 subs attached to the Denon LFE output. If you are already experiencing issues you might have a bad cable or a bad splitter, which sometime happens.
If you are really worried about it, you could always purchase a small inexpensive A/V distribution amplifier instead of just doing a 4 way split.
And I also agree with the poster above - what your noticing re: levels may also be related to room modes and phase cancellations.
If you are really worried about it, you could always purchase a small inexpensive A/V distribution amplifier instead of just doing a 4 way split.
And I also agree with the poster above - what your noticing re: levels may also be related to room modes and phase cancellations.
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As a general rule of thumb, if the amplifier's total input impedance is at least 10 times the amount of the source impedance, the level should not be affected.
Check the manuals to see what the Denon 3310ci output impedance and the total of the subs input impedance, if the total is not 10 times the source, you may want to use a line driver, or simply turn the subs up.
A "noticeable difference in the gain" does not always mean "signal degradation", is the Denon 3310ci clipping before the subs (with their gain wide open)?
Check the manuals to see what the Denon 3310ci output impedance and the total of the subs input impedance, if the total is not 10 times the source, you may want to use a line driver, or simply turn the subs up.
A "noticeable difference in the gain" does not always mean "signal degradation", is the Denon 3310ci clipping before the subs (with their gain wide open)?
Thanks everyone.....yes I am using the low levels on both the amp and the subs. Weltersys...I don't believe I have clipping in the amp as of yet. I haven't actually hooked up all four yet but with the two subs hooked up the gains on the subs themselves are at about a 5 out of 10 (each one). The LFE gain controlled in the amp is set at about -10 (the total scale on this setting is -12 to +12. I know I have plenty of room to add from the amp and from the subs (I think). I'm just worried I'm losing something (not just total volume) from the bass by splitting the LFE.
The only thing to be concerned about by splitting the sub channel rather than using a usually unnecessary distribution amplifier would be some loss of HF content. But since the bass management system on your Denon probably prevents any HF content above 200Hz from leaving the Denon's LFE output there is nothing you are missing by doing the splits.
Your concerns should really be directed to achieving the best sub placements in your room to get the most out of a multi sub set up.....
Splitting the signal once should not electrically make a difference in 99% of systems.
I don't believe you have an electrical effect, you have an acoustic effect. When you add the second sub, the low frequencies increase +6 decibels, due to the subwoofers loading each other. So yeah, the gain will be very different!
On another note, what are your main speakers? Most setups should not really run just LFE to the subs, ALL the lows should go to the subs, with high pass to the main speakers. What receiver or processor are you using?
It would also seem better if you were using all the same subwoofer, and experiment with placement. Or tell us why you want to add more subs-just volume? Or is there something about the sound quality you are not happy about?
I don't believe you have an electrical effect, you have an acoustic effect. When you add the second sub, the low frequencies increase +6 decibels, due to the subwoofers loading each other. So yeah, the gain will be very different!
On another note, what are your main speakers? Most setups should not really run just LFE to the subs, ALL the lows should go to the subs, with high pass to the main speakers. What receiver or processor are you using?
It would also seem better if you were using all the same subwoofer, and experiment with placement. Or tell us why you want to add more subs-just volume? Or is there something about the sound quality you are not happy about?
Sorry guys I should've mentioned in the first place what I'm trying to do. I hope by adding more subs to reinforce the subsonic stuff in movie soundtracks and music at the listening position first of all. Secondly id like to try and eliminate the standing waves as much as i can yet keeping the sub placement aesthetically ok. Im using m3's as the mains with the LFE + main option in the amp assignment chosen. The amp I'm using is a denon 3310ci. I've never used any software to analyze the sound in the room I've done it all by ear. I haven't done it yet but would I just be better off using the audessey setup mic the denon comes with or is there some other software somewhere that will do better?
WELL first of all, any correction software can't work miracles. So in an ideal world, you would get the subwoofers in "good" locations. That probably requires another thread, and posting a floor plan and description of your room.
I'd try the Audyssey setup first, it is quite sophisticated.
Check if your 3310's Audyssey can correct subwoofers individually-there may be a setup option for that.
I'm still unclear why you are using so many different models of subs. I can't say it's evil, but as a speaker engineer is just bothers me somehow. 😱
I'd try the Audyssey setup first, it is quite sophisticated.
Check if your 3310's Audyssey can correct subwoofers individually-there may be a setup option for that.
I'm still unclear why you are using so many different models of subs. I can't say it's evil, but as a speaker engineer is just bothers me somehow. 😱
Maybe try a DSP Inbetween. This could be beneficial for EQing different subs, setting different delays, changing levels of subs individually etc etc.
I would agree with others on the original question, splitting the signal shouldn't cause any issues.
Now a suggestion, if you're going 90% of the way to multi-sub by having 4 subs, you may as well go all the way. Get a Behringer processor (which would eliminate any potential signal worries anyway) and read up on Geddes multisub, or even pay Earl to do it, if he still does such things.
Now a suggestion, if you're going 90% of the way to multi-sub by having 4 subs, you may as well go all the way. Get a Behringer processor (which would eliminate any potential signal worries anyway) and read up on Geddes multisub, or even pay Earl to do it, if he still does such things.
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