Bridging? Bi-amping? What is this called? [Archive] - Audio & Video Forums


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01-06-2005, 12:10 PM
I have dual banana plugs that can plug into each other.

For giggles I decided to take another discreet channel of amplification and piggy back it into my Definitive center channel. The sound increased audibly and I'm assuming I'm getting a higher power, 4ohm load.

Would this be considered Bridging or bi-amping? Something else?


01-06-2005, 12:35 PM
Generally, bad things happen when you combine two channels into one speaker.

01-06-2005, 12:39 PM
I had a feeling. I'm a chancer and a tinkerer to be sure. I thought I blew my Acurus amp last week with the same type of asshattery but it turns out it just has blown fuses in the unit.

Isn't this what bridging is though? You have a speaker that works at 4 or 8 ohms and you bridge 2 channels of an amp into it producing 4 ohms?

01-06-2005, 12:58 PM
In a nutshell, bridging entails splitting the signal into the positive and negative swing of the input signal via a circuit (phase splitter?) before the two amps The positive is then sent to the input of one amp and the negative is sent to the input of the other amp.

so, each amp is only amplifying one half the waveform.

The output is taken from the positive side of one amp's output terminals and the negative side of the other.

You're simply running two amps in parallel into one speaker. You live a charmed life.

Nice place, Rumson. Bruce still live there?

01-06-2005, 01:29 PM
Ah I should have known I'm running parallel from my car audio days, thanks.

Bruce is still here, I live 5 blocks away from him. Besides seeing him play impromptu gigs at bars when I was younger I'm only seen him once in person while I've lived here. I motored by his house on my old Triumph and he stopped his raking and waved to ME. Made my day.

The rich and famous pretty much keep to themselves around here and it's a quite, comfortable and pretty place to live. I see you're from joisey too?

01-06-2005, 01:39 PM
Almost got a TR-4a back in "the day" but missed out by an hour. Wound up with a Sunbeam Alpine instead. No major regrets, though.

...but I really, really wanted that TR4!

01-06-2005, 01:46 PM
This is a '71 Triumph Motorcycle, a TR6c as if the name doesn't confuse it with a car enough...

Bruce is a car and bike buff and likes old stuff.

01-06-2005, 01:51 PM
Odds are I would have killed myself.

Bruce waved at you? Gee, all we get up here is the Sopranos. ;)

01-06-2005, 01:55 PM
We've got loads of Soprano wannabes in Red Bank. I just love the Sopranos.


01-06-2005, 02:02 PM
So, what kind of amp/receiver survived this torture test? Many would have winked out but it seems yours has the stamina that others lack. ...either that or, like I said, you're dang lucky.

01-06-2005, 02:12 PM
I believe now that you mention it, it was my Acurus A200X3 amp. I didn't blow the fuses that way though, I blew them while trying to hook my other zone audio up to it while it was on, dumb move.

I'm using one channel of a Fosgate 200x5 for the center at this moment.

01-06-2005, 02:36 PM
"Always power down all affected components when kerfutzing with the connections."

By any chance, is your center channel biwire/biamp capable? That is to say, are ther 4 connections, with each red/red and black/black pair joined by a jumper? And, if so, did you remove the jumper when you did that dasterdly deed? That might explain something.

then again, maybe not.

01-07-2005, 05:33 AM
The Definitive 2000 center does have the jumper and I left them on. I just fed all the power into the bottom plugs. In my head I was increasing the power to the amp.

01-07-2005, 05:44 AM
Had you removed them (the jumpers) you would have indeed accomplished a form of biamping. That's where you have independent amplifiers for the lows and the mid/highs. Assuming, of course, that the input to both amps was identical.

Incidentally, what's described above would be "passive biamping".

Another version is "active biamping", which is where an electronic crossover is employed before the two power amps in order to assure that the woofer only get the lows and the mid/highs go to those speakers.

01-07-2005, 05:48 AM
Is there a situation in which it would be ok to do what I did purely to get more power into the speaker? Let's say you have a speaker capable of 300 watts and have two identical 100 watt amps.

01-07-2005, 06:00 AM
Like I said up front, you got lucky. What you COULD do is remove those jumpers and passively biamp safely, which is what you almost did. That would effectively double the power to that speaker and afford about 3db additionial headroom.

but, as far as connecting more than one amp to one speaker terminal is kinda like tugging on Superman's cape or spitting into the wind, pulling the mask off the old Lone ranger, etc...

Hey, that might make a good song, no?

01-07-2005, 06:02 AM
Ok I'll try that. I have the extra amp channels available so I might as well play.