CurtPalme.com Home Theater Forum

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

OK so I don't think I understand the real benefits of Bi amping. I see if you bi wire you are changing the load to 4 ohms, yet it seems to make much more improvement than just that. If you bi amp you would (using 2 amps) keep the load at 8 ohms and be able to direct more power to the high and low. (@ 4 ohms you also have more power) But power isn't an issue for me. If I was using an EQ on at least one amp I see where you would get more control over the high and low. What am I missing here ?

stridsvognen · Guest

Its quite simple.. Try it.. Listen.. And connect it the way it sounds best, mostly the simple setup will sound best.

winny · Posted: Fri Mar 28, 2014 7:13 pm Post subject:

If you bi-wire, you don't change the impedance at all. It stays the same.

If the drivers are mounted on the same baffe and you move to bi-amping and time-align the distance mismatch in the crossover, the improvement can be significant. Your milage may vary though depending on what you start with.

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

How is it possible if I am running 2 speakers (essentially) off one side of an amp that the impedance doesn't change ? It has to. You cant just keep adding speakers and not change the impedance. Now I am really confused.

winny · Posted: Fri Mar 28, 2014 7:45 pm Post subject:

Oh, you have two sets of speakers. Bi-wireing usually refers to driving each element with its separate wire.
If you don't want to ditch the (assumed) passive filter in any way and you just want to drive several full range speakers you can ignore my comment. Two 8 ohms speakers in parallel will of couse work out to 4 ohm.

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

My speakers are set up to bi wire- bi amp. They come stock with metal straps to "tie" the high to the low. It is essentially 2 speakers in one cabinet. the "high" has a tweeter and 2 midranges and the "low" has 3 woofers. Its not really any different than stacking a small speaker on top of a woofer.

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

When I used to DJ I would bi amp the PA cabinets. I would run a 75 watt head (amp) to the tweeter and a 300 watt head to the woofer. But each head had its own controls as to volume and frequency. I really cant get that without EQ's. As far as bi wire goes are you saying that the crossover splits in 2 complete separate halves ? I have never seen anything like that. I really want to understand this. Sorry for being a PITA.

CIR Engineering · Posted: Sat Mar 29, 2014 5:06 pm Post subject:

CIR Engineering · Posted: Sat Mar 29, 2014 5:25 pm Post subject:

Also, whether you run single wire, biwire, or biamp, you are not changing the static impedance of the speakers. In any of the three configurations an 8 ohm speaker remains an 8 ohm speaker (and so on). I don't know why biwiring should improve the sound of some speakers. I was skeptical, but like you I could hear a clear benefit to biwiring when I tried it the first time about 20 years ago. Even my girlfriend at the time (who couldn't give a rat's ass about sound quality) asked me why the sound was better and I hadn't even told her I changed anything. I was really surprised when she noticed.

My own theory is that it has something to do with how heavy the speaker wire is. For example, I found that if I biwire with 14 AWG than there is a profound difference. But, I find that if I biwire with 12 AWG than there is little or no difference. Because of this I now always run 12 AWG speaker cable no matter the amp rating.

...truthfully though I have not biwired for a long time because I have been setup with biamped fronts for years now.

Just to be clear, biwiring is when you run two pair of wires from one output on an amplifier to two inputs on the same speaker. Said speaker has the bridge between input terminals removed just like with biamping.

And on a side, biamping with the the Audyssey room correction is really a sweet trick. Since the two amps for each speaker can't be completely matched there is some inherent error when you biamp. But the Audyssey will correct most of this with its equalization.

craigr

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

Thanks for clearing that up.

416ray4538 · Joined: 14 Jul 2009 Posts: 517 Location: near Toronto Ont

Capacitors and chokes are passive components; amplifiers ( op-amps) are active components. The crossover in the speaker cabinet is passive by this definition.
Amplifiers can be expensive if you want one that does it all:
Lots of current for the bass, clean mid, high speed to control harmonic distortion and intermods. Common practice is to then ask the expensive amp to do its work while being isolated from the speakers by a crossover. Bi or tri amping allows you to Select amifiers that do well in their range instead of doing it all. The bass and mid amps never see the highs and intermods and the tweet amp doesn't have to deliver the kind of current the woofers need. Each amplifier is connected directly to it's speaker with no components but wire in the way.
More total power is a minor advantage.
So matching amps to the need, getting the crossover out of the connection from amp to speaker, and the probably higher quality of crossover components improve the sound.

wowchad · Joined: 29 Oct 2009 Posts: 53 Location: Milwaukee'ish, WI

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

OK So now that the subject has been brought up again what about this. Could you Bi amp a pair of speakers using a 2 channel amp with A and B outputs ? Using both channels A and B. I see no reason why not.

stridsvognen · Guest

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

I don't understand why a stereo amp able to drive 4 speakers wouldn't accomplish the same thing.

**AnalogRocks** · Posted: Wed Jul 09, 2014 5:44 am Post subject:

**Curt Palme** · Posted: Wed Jul 09, 2014 12:44 pm Post subject:

Not to confuse things, but to me, Craig has the terminology backwards.
An active crossover uses chips, and is powered, so to me, that's the one that works at a preamp level, before the amps.
A passive crossover uses no external power supply, and is the one built into the speakers.

jeffslife · Joined: 17 Apr 2010 Posts: 4190 Location: ohio usa

Now I am really confused. 4 amps to run 2 speakers.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Jeremy112 · Joined: 28 Sep 2006 Posts: 2649 Location: Fond du Lac, WI

Stereo amplifiers work as follows: 2 channels; each channel is 1 amplifier (left amp, right amp. Say your speakers are 100 watt 8 ohm load.

Using only 2 speakers, with 1 set of wires in a non bi-amp setup will give you 100 watts at 8 ohms per speaker.

Now, the speaker AB does this - You have 4 speakers, 1 set on A and one on B, what the receiver does is lower the impedance of the amplifier to be able to output more power to the additional speakers. The extra pair of speakers is still utilizing the same left & right channel that the first set is using.

Bi-amping as many have said, uses multiple amps. 2 amps for 1 speaker (3 in some cases, depending on the speaker of course). Bi-amping gives more power if im not mistaken, but the impedance of your 8 ohm speaker will stay 8 ohms because each driver in the cabinet is wired up/built as such.

I honestly cant say much about Bi-wiring, I really didn't know there was a difference until I read this thread. But it makes sense now after reading it.

Point is, many confuse Speaker A/B/C as additional amplifier channels, THAT IS NOT the case. pressing those buttons just changes the way the circuit is wired. it doesn't give you extra amps or channels. Never has on a stereo receiver, and I assume it never will.