I don't know if there is an answer to this, but I was thinking about something last saturday while installing 2 subs, box and amp in a new 6 series BMW.
The customer wanted to keep the factory HU, and everything else factory. Luckily for me there was a pair of 6" bass drivers in the back under the armrests. I had to use a line output converter. Here is my question:
The LOC was connected to the left and right bass drivers, then went to the amplifier (2channel bridged) by 2 RCAs.
If there is any variation in the sub frequencies from left to right will that make the subs sound bad? I know that the amplifier would mesh the two channels with them being bridged, but I keep thinking that if there is any stereo seperation or variation of frequencies from left to right it would make the subs mud out. Bottom line, is it better to connect both input wires to the same driver for source, or connect them from both sides and get that extra little bit of juice for the RCA inputs?
Replies (3)
swez on 12/4/2006 03:09:53
Good questions Kit. Might have a few thoughts for ya too.
Bass is usually tracked equally on the L/R channels. Since low bass energy is not directional, (Like Mids and Highs) there is no need to break bass out into stereo channels. Basically, there is no real need for stereo separation. We cannot hear it anyway.
Here, summing channels L/R together, (For low bass drivers) makes the most sense. There is no sense of stereo imaging for low bass tones.
I have heard a few guys talk about tracks that have dual bass drum kicks that were mixed for L/R stereo. But those are far and few between. (If we used headphones, we would hear that well.) However, in a typical system, it would be very difficult to pick all that out.
In a nutshell, bridging a 2 channel amp will sum L/R bass tracks and net a stronger MONO signal to the subs. Does that calm your restless thoughts? SMILE
Swez
cplkittle on 12/4/2006 03:54:13
somewhat..
at least for everyday applications.
any insight on pro applications?
That bass mechanics CD has several tracks that play a solid frequency on the left channel and .5 Hz above that frequency on the right channel. This dissonance is supposed to net an increased SPL. In this case, though, you would need seperate enclosures for left and right channels to yield the extra dB or so.
At least that is what I think.. I dunno
swez on 12/4/2006 12:36:50
For Pro applications I have been party to, it's always a mono channel system for subs. The number of subs used and power amps are scaled to the event and venue. The main goal here is to provide as much bass reinforcement as is requested by the guy who's paying the bills. Here, we always choose amps with plenty of non-clipped headroom to feed as many subs as is required. At $600 bucks a pop, (or more) we cannot afford to blow a sub.
As for slight frequency changes from one channel to another, think about tuning an instrument... (Say.. a pair of trumpets) when two like instruments are slightly out of tune, we get a slight dissonance that produces a slight warble tone when combined. Is that desirable or favorible? In a general sense, I think not.
Now, in the SPL Comps world, I dunno... never tried it and don't know if this would be a positive SPL kicker or not. However, if we fed a MONO amp with L/R test tones, the amp would still combine these tones and all subs powered off that amp would exhibit the same composite blend of both tones.
Would that increase SPL? I don't know. And since I don't get too involved in pure SPL type applications, my comments are limited in that area. It's just not my cup of tea is all. It might be... but only if someone hired me to engineer, design and install such a rig. Otherwise, what's the point? I'd still consult experts that know how to squeeze every dB of sound pressure out of a given system.
Swez
The customer wanted to keep the factory HU, and everything else factory. Luckily for me there was a pair of 6" bass drivers in the back under the armrests. I had to use a line output converter. Here is my question:
The LOC was connected to the left and right bass drivers, then went to the amplifier (2channel bridged) by 2 RCAs.
If there is any variation in the sub frequencies from left to right will that make the subs sound bad? I know that the amplifier would mesh the two channels with them being bridged, but I keep thinking that if there is any stereo seperation or variation of frequencies from left to right it would make the subs mud out. Bottom line, is it better to connect both input wires to the same driver for source, or connect them from both sides and get that extra little bit of juice for the RCA inputs?
Replies (3)
swez on 12/4/2006 03:09:53
Good questions Kit. Might have a few thoughts for ya too.
Bass is usually tracked equally on the L/R channels. Since low bass energy is not directional, (Like Mids and Highs) there is no need to break bass out into stereo channels. Basically, there is no real need for stereo separation. We cannot hear it anyway.
Here, summing channels L/R together, (For low bass drivers) makes the most sense. There is no sense of stereo imaging for low bass tones.
I have heard a few guys talk about tracks that have dual bass drum kicks that were mixed for L/R stereo. But those are far and few between. (If we used headphones, we would hear that well.) However, in a typical system, it would be very difficult to pick all that out.
In a nutshell, bridging a 2 channel amp will sum L/R bass tracks and net a stronger MONO signal to the subs. Does that calm your restless thoughts? SMILE
Swez
cplkittle on 12/4/2006 03:54:13
somewhat..
at least for everyday applications.
any insight on pro applications?
That bass mechanics CD has several tracks that play a solid frequency on the left channel and .5 Hz above that frequency on the right channel. This dissonance is supposed to net an increased SPL. In this case, though, you would need seperate enclosures for left and right channels to yield the extra dB or so.
At least that is what I think.. I dunno
swez on 12/4/2006 12:36:50
For Pro applications I have been party to, it's always a mono channel system for subs. The number of subs used and power amps are scaled to the event and venue. The main goal here is to provide as much bass reinforcement as is requested by the guy who's paying the bills. Here, we always choose amps with plenty of non-clipped headroom to feed as many subs as is required. At $600 bucks a pop, (or more) we cannot afford to blow a sub.
As for slight frequency changes from one channel to another, think about tuning an instrument... (Say.. a pair of trumpets) when two like instruments are slightly out of tune, we get a slight dissonance that produces a slight warble tone when combined. Is that desirable or favorible? In a general sense, I think not.
Now, in the SPL Comps world, I dunno... never tried it and don't know if this would be a positive SPL kicker or not. However, if we fed a MONO amp with L/R test tones, the amp would still combine these tones and all subs powered off that amp would exhibit the same composite blend of both tones.
Would that increase SPL? I don't know. And since I don't get too involved in pure SPL type applications, my comments are limited in that area. It's just not my cup of tea is all. It might be... but only if someone hired me to engineer, design and install such a rig. Otherwise, what's the point? I'd still consult experts that know how to squeeze every dB of sound pressure out of a given system.
Swez
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