Bi-wiring/Bi-amping explained

steveinaz

Bi-wiring requires speakers that have "bi-wire" capability, that is 2 sets of binding posts (4 posts total, each speaker). Bi-wire capable speakers can also be "bi-amp'd."

Keeping things simple, bi-wiring allows you to run speaker connections seperately to the high/low sections of your speaker, minimizing the components used in the cross-over network (less is usually better in Audio). Proponents of bi-wiring state that low frequency signals will traverse the bass wires, and high frequency signals will traverse the mid/treble wires, thereby introducing less intermodulation distortion. The debate forever goes on about its "real" effectiveness. I can tell you that I've tried both for over 30 years, and have reverted to a single run of high quality wire. Opponents to bi-wiring claim that you simply end up spending twice as much on speaker cables, and get negligible--if any--improvement.

My opinion? Rather than spending money on less expensive wires so you can afford bi-wiring---spend more money on a very good set of wires and use a single run. Do you need to spend 800 bucks on speaker wire? Hell no. Wire, like everything has a point of diminishing returns. I'm extremely happy with my $280 set of AudioQuest Granites. If your pockets are deep--go for it and bi-wire, just don't sacrifice quality of cable.

Bi-amping is much more effective, but also much more expensive. It requires 2 identical amps (ideally). One amp is used for mid/highs, the other amp for low frequencies. I have bi-amp'd in the past with very nice results--but no longer have 2 amps. Again, IMO its better to spend the bucks on one powerful good quality amp, then to buy 2 so-so amps.

Hope this helps.

Here's my setup for reference:

Parasound HCA-1500A amplifier
Parasound PHP-850 Preamp
Cambridge Audio D500SE CD Player
Athena AS-F2 tower speakers
Audioquest Granite speaker wires (single run)
Audioquest Sidewinder interconnects

F1nut

Steve,

Welcome to the forum.

I will have to disagree with your statement that bi-amping requires 2 identical amps. Actually one of the advantages of bi-amping is that one can optimize one amp for the mid/high range and another for the low range. The only thing that must be matched is the gain. In using two different amps with different gain levels, you must have a level adjustment. It is often easier to have identical amps rather than trying to adjust the level.

F1

steveinaz

You're right, it can be done with different amps, but note that I said (ideally) above. It can be troublesome to match different amps at times.

F1nut

Duely noted. I just wanted to present all the options of bi-amping.

Tour2ma

Originally posted by steveinaz
Bi-wiring ... minimizing the components used in the cross-over network

Actually it makes no difference at all in the utiization of the cross over network. A bi-wirable speaker has separate entry points to the high and low frequency portions of the crossover. The two portions are in parallel whether you use a single wire run with jumpers, or bi-wire.

The same would be true for the same speaker, if it had only one pair of posts. Effectively the jumper would just be inside the cabinet.

Originally posted by steveinaz
Bi-amping ... One amp is used for mid/highs, the other amp for low frequencies.

Well, again, not really. Both amps amplify the full signal, it's just that large portions of the output of each are not of use to the drivers being fed (moreso in the case of the tweeters). There may be some net gain via the external feedback loop, if the amp design can make use of the "unused" signal.

As you infer, bi-amping is often just a means of over coming a power deficiency, and it can be a more economical approach than upgrading to a single, more powerful amp.

As F1 pointed out, effective use can be made of "unequal" amps producing the same gain. There are other characteristics that are worth matching as well, including input sensitivity, slew rate and damping factor. The amount of power difference that can be employed depends on the speaker.

In the case of Polks with tweeters and mid-woofers, the difference can be substantial as there is so little power requirement in the higher frequencies. Certainly a 50% less powerful amp would be adequate, probably a 75% and possibly even a 90%, depending on music and listening levels (but personally, I wouldn't go that low).

However, in a three way design, where most often the posts are split between feeding the tweets/ mid's together and the woofer(s) separately, 50% less to the upper frequencies would be as low as can see going.

Just trying to amplify the discuission here...

dorokusai

To start the thread with a end all statement was doomed for discussion. I agree there are other aspects that you did not touch on in the starter, as the above statements make clear. In theory, EVERYTHING works, its in application that the wrench or individual becomes a player.

The gain adjustment can also compensate for pre-amp levels and/or "THX" levels that are mismatched, in addition for cross amping brands.

There are alot of variables that affect Bi-Anything, I personally think its just ground level useable. You, the listener/owner, decide.

steveinaz

Keep in mind that anyone who is asking the question "what is bi-wiring" is probably new to hi-fi and doesn't have the technical background to understand the theories associated with bi-wiring/bi-amping; this is why my initial thread was kept simple, non-technical and to the point. I could have given the scientific answer--but thats already been done here numerous times, yet everyday someone else aks "what is bi-wirng?" It became obvious to me that the answers they were getting were far too technical.

You misunderstood my statement on bi-amping; of course both amplifiers reproduce the entire signal--what I was saying is that the best approach to bi-amping is to dedicate 1 amp for mid/high and the other amp for low freq's.

Much of this, in my opinion, is voodoo science. I've been deep into hi-fi for 30+ years and have found that bi-wiring improvements are largely "psyhcological" and extremely detremental to your wallet if done correctly. If you want true improvements; use your dollars on a top-notch source component, rather than a double-set of expensive speaker cable. A better source component will reward you with 10 times the improvement that bi-wiring would.

Just ask Thiel, Wilson, Magnepan, Athena, Vandersteen, Dyna Audio and a few other top-shelf speaker manufacturers why they don't support bi-wiring.

My point is this, spend your bucks on good solid quality products first; then experiment with bi-wiring or whatever your wallet can support.

HBombToo

Originally posted by steveinaz


Much of this, in my opinion, is voodoo science. I've been deep into hi-fi for 30+ years and have found that bi-wiring improvements are largely "psyhcological" and extremely detremental to your wallet if done correctly. If you want true improvements; use your dollars on a top-notch source component, rather than a double-set of expensive speaker cable. A better source component will reward you with 10 times the improvement that bi-wiring would.

Agreed in whole and well said.

I would also like to add a quick thought on Bi-Amping.

I agree with the notion that a less powerfull amp can be used for the tweeter side but at your listening levels it must not clip.

Also, the crossover has a certain frequency response and outside of this response will present no load on an amplifier. In short the preamp will see the entire band but as we seperate the high and low pass sections on the speakers and add another amp, each amp will only be loaded for each bandpass section its connected to.

HBomb

steveinaz

Originally posted by HBombToo

Also, the crossover has a certain frequency response and outside of this response will present no load on an amplifier. In short the preamp will see the entire band but as we seperate the high and low pass sections on the speakers and add another amp, each amp will only be loaded for each bandpass section its connected to.

HBomb

Precisely! You said it better than I could; thanks for the assist.

dorokusai

Sounds good to me

Tour2ma

steve,

I actually agree with your bi-wire/ bi-amp stance in general. While I have utilized both, I have not heard a night and day difference.

I am honestly not trying to show you up or anything like that. What I was attempting to do was to address a couple statements in your original post that either are not, well.., accurrate or I felt were potentially misleading. For example, the statement that bi-wiring eliminates part of the cross-over. Many think this and it's not the case. What it is, is one of the falicies that the "voodoo" springs from.

Anyway, in that spirit, I must point out that my Maggie 1.5's are bi-wirable, as are many other models. There are other Maggies that are not.

Henry,

Agree with Steve on your bi-amp clarifications. In our many discussions on bi-amping, I had not seen the load issue put quite that way before. Something to reflect on a bit more...

steveinaz

That's what forums are for, sharing theories, ideas, etc.

I stand corrected on the cross-over issue, after doing a little research I found that I had fallen prey to a misleading theory...this being the case--it seems to prove my point further that bi-wiring (as I have found) is probably an expensive waste of time. I've tried speakers connected both ways many times through the years and always end up going back to a single run. I think sometimes the "theory" is way more exciting than the actual results experienced.

I doubt seriously that any of us, save a 6 month old audiophile, would be likely to hear the benefits of bi-wiring, and I just can't justify slapping down big bucks on 2 sets of cables.

Great discussion!

rastaboom

I can't tell you the difference this made to the sound of my Polk Audio Rti10 tower front speakers ! The benefits should be made more clear in the documentation - it took me a few years to stumble on this forum and others talking about the great sound from bi-amping.

If you have speakers that have 4 posts behind each - two for the bass, two for the midrange/tweeter - and you're only connecting to 2 and using the bridge to feed the other 2, your speakers are most certainly underpowered. I couldn't understand why these not-too-cheap speakers weren't very impressive in my setup. I was using the back surround speakers for a 7.1 sound - but it was a waste. It resulted in underpowered front speakers and too much sound coming from the back and sides....and the back information is just faked information !!

Just recently I changed to 5.1 by setting my Denon AVR-1907 rear-surround amplifiers to bi-amp the front r/l bass. The difference is simply AMAZING !!!

Now I know why these speakers cost so much !

When BluRay and others start putting out a big chunk of their movies in 7.1 - and when the HD channels on TV start doing the same - I will most certainly invest in a 7.1 amp that also supports bi-amping. I simply will never underpower those towers again !!!

wutadumsn23

Thanks for your input rasta, and welcome to Club Polk. Having said that, next time feel free to start your own thread, since this one is over 6 years old, lol. Stick around and enjoy our little forum, and get ready to empty your wallet, lol.

-Jeff

F1nut

Talk about a blast from the past......anyway...

If you have speakers that have 4 posts behind each - two for the bass, two for the midrange/tweeter - and you're only connecting to 2 and using the bridge to feed the other 2, your speakers are most certainly underpowered.

That comment is far, far from the truth.

It resulted in underpowered front speakers and too much sound coming from the back and sides....

Yep, that's what happens when you don't calibrate the set up. Did you have the fronts set to small or large before and what are they set to now?

comfortablycurt

rastaboom wrote: »

I can't tell you the difference this made to the sound of my Polk Audio Rti10 tower front speakers ! The benefits should be made more clear in the documentation - it took me a few years to stumble on this forum and others talking about the great sound from bi-amping.

If you have speakers that have 4 posts behind each - two for the bass, two for the midrange/tweeter - and you're only connecting to 2 and using the bridge to feed the other 2, your speakers are most certainly underpowered. I couldn't understand why these not-too-cheap speakers weren't very impressive in my setup. I was using the back surround speakers for a 7.1 sound - but it was a waste. It resulted in underpowered front speakers and too much sound coming from the back and sides....and the back information is just faked information !!

Just recently I changed to 5.1 by setting my Denon AVR-1907 rear-surround amplifiers to bi-amp the front r/l bass. The difference is simply AMAZING !!!

Now I know why these speakers cost so much !

When BluRay and others start putting out a big chunk of their movies in 7.1 - and when the HD channels on TV start doing the same - I will most certainly invest in a 7.1 amp that also supports bi-amping. I simply will never underpower those towers again !!!

Well that's a whole lot of bad information...but whatever works for you.

Your speakers are still receiving the exact same amount of power from your AVR. Every channel on your AVR is powered by one common power amplifier, so the speaker is only going to draw as much power as it needs...regardless of how many outputs it's hooked up to.

Bi-wiring with an AVR has zero benefits in my experience. Others have reported improvements though...

wutadumsn23

comfortablycurt wrote: »

Well that's a whole lot of bad information...but whatever works for you.

Your speakers are still receiving the exact same amount of power from your AVR. Every channel on your AVR is powered by one common power amplifier, so the speaker is only going to draw as much power as it needs...regardless of how many outputs it's hooked up to.

Bi-wiring with an AVR has zero benefits in my experience. Others have reported improvements though...

Yup, I am with you on this one Curt.

-Jeff

wutadumsn23

Doh, man you have all the fun Mike. Besides I am closer, you are way out in the ocean!!

wutadumsn23

LOL, you kill me Mike. Looks like it's up to you, me, and Curt to **** on threads now with Russ being on hiatus, lol.

wutadumsn23

Yikes.

edbert

comfortablycurt wrote: »

Bi-wiring with an AVR has zero benefits in my experience. Others have reported improvements though...

I would actually disagree to a point. I think it depends on the speakers that you are bi-amping. I have a very modest system in having Monitor 40's as my mains. My AVR is a 7.1 receiver and you can use the two surround back channels as the available option to bi-amp the mains effectively giving you 5.1. I did back to back comparison using the same movie sequence in Borne Identity and u-571. I noticed a fairly significant improvement in the sound going from regular amplification to bi-amping. Granted, I am running a smaller Monitor series speaker and not LSi's, so the difference I hear will be vastly different from someone running a higher end speaker. At the same time, someone used to hearing a higher quality speaker will probably think my setup sounds like piss no matter how you hook it up because they are used to a better speaker with lots of good clean power being fed to it. Overall, this is all very subjective and it really depends on the quality of the components being used and the level of quality a person is used to hearing coming out of their speakers.

EDIT: Alright, so I am apparently still asleep or something, I misread the section that I quoted as saying bi-amping and not bi-wiring. I agree with the bi-wiring because I tried that as well and didn't notice any improvement. The rest of what I said is just my .02 on an issue that wasn't even brought up. Consider it my contribution to the forum for the year.

cabbiepimpin

Question: clearly, bi-amping by redirecting the rear surround channels on an AVR is useless since all the channels derive their power from the same amplifier source.

However, does this analysis still pertain to AVRs which purportedly have different/discrete power sources for each channel? I have a Denon AVR1909; I believe the website markets it as having "independent power supplies."

If this is so, then would not bi-amping with the 1909 actually derive a benenfit since each run to each of the front speakers is drawing from a separate power source? Or is this all marketing gimickery?

steveinaz

Seeing a post from yourself 6 years ago, is like the first time you heard your voice on a cassette recorder

---

you sound like a dork...

LOL

Cpyder

If I have two 2-way speakers and two amps, would it be better to just use one amp per speaker and not bi-amp. I feel like using one amp to power the tweeters would basically be a waste of an amp since the tweeters don't need much juice, but the woofers would.

1 amp / 1 speaker

or

bi-amp?

steveinaz

I would not bi-amp in that setup.

anhchungdoan

comfortablycurt wrote: »

Well that's a whole lot of bad information...but whatever works for you.

Your speakers are still receiving the exact same amount of power from your AVR. Every channel on your AVR is powered by one common power amplifier, so the speaker is only going to draw as much power as it needs...regardless of how many outputs it's hooked up to.

Bi-wiring with an AVR has zero benefits in my experience. Others have reported improvements though...

When a person using the passive bi-amp method from the AVR as the poster stated, there is nada, zero better on SQ. The amp will see only 50W instead of 100W go to the hi and the same go to the low frq. and as a result, the amp will have to work harder and draw more current ( higher distortion and running hot= heat issue).

Bob Carver recommended vertical bi-amp for his Sunfire Signature multi channel amp, it may work due to the sound characteristic of the Voltage/Current ouput however the benefit remains to be seen as subjective issue.

Bi-amping with 2 different type of amps or with 2 separated same types of amp will require an active X-over ( NHT/Bryston) but one needs to make sure that the procedure is in compliance with the speakers manufacture's recommendation.

anhchungdoan

cabbiepimpin wrote: »

Question: clearly, bi-amping by redirecting the rear surround channels on an AVR is useless since all the channels derive their power from the same amplifier source.

However, does this analysis still pertain to AVRs which purportedly have different/discrete power sources for each channel? I have a Denon AVR1909; I believe the website markets it as having "independent power supplies."

If this is so, then would not bi-amping with the 1909 actually derive a benenfit since each run to each of the front speakers is drawing from a separate power source? Or is this all marketing gimickery?

You are getting there, brother. I'd rather using bridge mode than passive bi-amp if i need more juice to the FL/FR.

anhchungdoan

Keiko wrote: »

Bend over there then, Curt. I'll bi-wire ya.

Nice 2 channel amp but I will have to pass.

concealer404

Cpyder wrote: »

If I have two 2-way speakers and two amps, would it be better to just use one amp per speaker and not bi-amp. I feel like using one amp to power the tweeters would basically be a waste of an amp since the tweeters don't need much juice, but the woofers would.

1 amp / 1 speaker

or

bi-amp?

Try both ways. See which sounds better. Can't take that long to find out, right?

vc69

comfortablycurt wrote: »

Well that's a whole lot of bad information...but whatever works for you.

Bi-wiring with an AVR has zero benefits in my experience. Others have reported improvements though...

That is an opinion (that I happen to share). However, rastaboom was referring to Bi-amping. Which I also agree is a waste of time with a receiver.

anhchungdoan wrote: »

Bi-amping with 2 different type of amps or with 2 separated same types of amp will require an active X-over...

zackly

This thread seems to have a misunderstanding of what bi-amping is.

Bi-amping (or tri/quad) is done (properly) with an active crossover and some serious room analysis/tuning. It sometimes involves a 1/3 octave graphic EQ (in some cases parametric) for each channel, separate low and high cabinets (not always) and a very expensive (accurate) real-time analyzer/mic and a frequency/noise generator for setting it all up. We do it in live concert sound applications all of the time.
It is not anything like bi-wiring and certainly quite different than just hooking up two separate amps and adjusting the levels.

anhchungdoan

vc69 wrote: »

That is an opinion (that I happen to share). However, rastaboom was referring to Bi-amping. Which I also agree is a waste of time with a receiver.



zackly

This thread seems to have a misunderstanding of what bi-amping is.

Bi-amping (or tri/quad) is done (properly) with an active crossover and some serious room analysis/tuning. It sometimes involves a 1/3 octave graphic EQ (in some cases parametric) for each channel, separate low and high cabinets (not always) and a very expensive (accurate) real-time analyzer/mic and a frequency/noise generator for setting it all up. We do it in live concert sound applications all of the time.
It is not anything like bi-wiring and certainly quite different than just hooking up two separate amps and adjusting the levels.

Please enlighten me about bi-amping. If my pre-amp has only one set of pre-out and I want to use one amp to drive my woofer and another amp to driver my electrostat panel, what is your configuration without an external active cross-over?