Bi-wire or Bi-amp

[brands]

I have a NAD T-773 and JBL Studio L890 does bi-wiring do anything and what do i need to bi-amping and does it matter?

[Johnd]

There are a lot of threads on these topics. Just use your search function. The general consensus is that biwiring does little, and biamping does not provide much either unless it is active. Check out the editor's view:

http://www.audioholics.com/education/cables/bi-wiring-from-amplifier-to-loudspeaker
and
http://www.audioholics.com/education/cables/bi-wiring-part-2-the-cable-conundrum

Happy reading. Cheers.

[Joe Schmoe]

If your goal is to play your system brain-meltingly loud, then active biamping might help. Biwiring does not merely do "very little", it does nothing whatsoever. (To see this clearly, simply sketch a wiring diagram.)

[Johnd]

Biwiring does not merely do "very little...

Well, Schmoe, I again have to disagree. Firstly, Paradigm still recommends biwiring on their speakers. Secondly, the blanket statement of "it does nothing whatsoever" holds not one drop of water if one biwires 20 ga (or any under-gauged wire) speaker wire requiring a heavier gauge. ;)

[fmw]

Well, Schmoe, I again have to disagree. Firstly, Paradigm still recommends biwiring on their speakers. Secondly, the blanket statement of "it does nothing whatsoever" holds not one drop of water if one biwires 20 ga (or any under-gauged wire) speaker wire requiring a heavier gauge. ;)

I hate to tell you, John, If Paradigm recommends it then they are pandering to the religious high end crowd. Bi wiring not only does nothing, it can't do anything. The engineers at Paradigm know that just as well as I do. If someone were to use wire of such a small gauge that it affected speaker performance, the solution is to use a heavier guage wire rather than adding more wires.

[Joe Schmoe]

Well, Schmoe, I again have to disagree. Firstly, Paradigm still recommends biwiring on their speakers. Secondly, the blanket statement of "it does nothing whatsoever" holds not one drop of water if one biwires 20 ga (or any under-gauged wire) speaker wire requiring a heavier gauge. ;)

One would get an identical result by using a heavier gauge wire. Biwiring has nothing to do with it.
The only reason I can think of that a speaker company would recommend biwiring is that it might make them seem more "high end" to some of their more gullible customers.:rolleyes:

[zildjian]

Brands do you see what you just started??? :D again...

Biamping and biwiring are two completely different things, and subject to much debate when you consider biwiring (see above posts...).

Biamping, yes there can be substancial benefit to biamping if done properly. You have to ensure that the levels are matched between the 2 amplifiers. In other words, if you use a much larger amp to run your mid woofers and a smaller amp to run your tweeters, there can be a level difference during playback where your tweeters are too quiet (of course, they aren't getting as much power at high volumes OR the linearity of amplification may not be identical/matched between the two different types of amps). It's suggested to use identical amps when biamping, or at least close enough to compliment each other.

Next with biamping is the type of crossover used: active vs. passive.
An active crossover splits the signal before it gets to the amplifier. In other words, it splits the signal into a high frequency signal and a low frequency signal, each of which can then be directed to their appropriate amplifier. This provides a more efficient means of amplification for each signal path as the amp driving the low frequency drivers only amplifies the low frequencies in the signal as that's all their input signal contains...
With a passive crossover (such as a crossover built into your speakers for example, with multiple binding posts on the back of your speaker labeled high & low), a full range signal (both highs and lows) is sent to both amplifiers. Each amplifier then has to amplify that whole frequency band and send it to the to the corresponding binding posts, where the internal crossover passively eliminates the unwanted frequencies and allows pass only the highs for the tweeters, and lows for the woofers. In this set up, you'll still be able to deliver more power to your speakers than if you used just one of the amps, but each amp is still working to amplifier the entire signal, so again it's not as efficient as the active crossover method described above.

Biwiring: here's your debate! I have not heard a difference in biwiring when I tried it. As long as the resistance is low enough in your speakers cables when you single wire your speakers, I wouldn't worry about biwiring unless you just want to experiment with it. That being said, if you do want to try it, nothing anybody can say on this forum should stop you. Just don't go buy overpriced speaker cable to try it! Again, I haven't ever noticed a difference, and I don't currently biwire my speakers; maybe I would if I still had a surplus of speaker cable, but I'm not rushing out to buy more to do so. Long story short, anybody would be hard pressed to prove if biwiring makes a difference vs. using a single run of low resistance cable.
Brad

[Adam]

With a passive crossover (such as a crossover built into your speakers for example, with multiple binding posts on the back of your speaker labeled high & low), a full range signal (both highs and lows) is sent to both amplifiers. Each amplifier then has to amplify that whole frequency band and send it to the to the corresponding binding posts, where the internal crossover passively eliminates the unwanted frequencies and allows pass only the highs for the tweeters, and lows for the woofers. In this set up, you'll still be able to deliver more power to your speakers than if you used just one of the amps, but each amp is still working to amplifier the entire signal, so again it's not as efficient as the active crossover method described above.

Question. Is it possible to design a speaker such that the high frequency signal from both amp inputs go to the tweeters and same for the low frequencies to the woofers? A more sophisticated cross-over, perhaps, but wouldn't the power from both amps be utilized in that case?

[snickelfritz]

Passive bi-amp'ing completely isolates the woofer EMF voltages from the mid-treble network. (since the EMF voltages are damped by a completely separate amplifier)
It also isolates distortions from the bass amplifier, from the amplifier driving the mid-treble section.
You need two stereo amplifiers, a set of pre-out connections from your preamp/processor, and a set of Y-connectors to split the signal.
It's probably not worth the expense of buying another amplifier though.

Active bi-amp'ing is obviously much better and well worth the expense, since it removes the passive networks and their associated power consumption and phase anomalies from the loop, and allows trimming of the response, as well as isolating the bass and mid-treble amplifiers from each other.
ie: you can clip the bass amp without sonic penalty (or danger to the tweeters) in the mid-treble range.

Bi-wiring is cheap, and is probably the "ideal" way to connect your speakers if they are designed for it.
The purported benefits are much the same as passive bi-amp'ing:
Separate ground paths for each section of the passive network, allowing EMF voltage from the woofer to be more effectively damped by the amplifier, thus removing it as a variable (regardless of how insignificant it might be) in the performance of the high-pass network.
It's essentially a free tweak that does no harm and may yield some audible benefits.

BTW, the fact that bi-wire cables are "connected to the same amplifier output" does NOT mean that the electrical paths between the passive networks and amplifier are the same as a hookup with a single pair of wires and jumpers between the sections at the speaker inputs.
This is often poorly understood and misrepresented in discussions of this topic.

Also, the effective thickness or gauge of the wiring is not changed in any way when bi-wiring.
ie: two sets of 12gauge wire used to bi-wire a speaker does not "double" the effective gauge relative to a single run of 12gauge wire. It's exactly the same, since they are connected to separate and completely isolated terminals at the speaker.
The low-pass network draws zero voltage through the wires connected to the high-pass network and vise-versa.
Nor would matter at all if it did double the thickness, unless the wires are extremely long and/or under-sized.

The benefits of bi-wiring are fairly subtle, and will vary considerably with the type of program material and characteristics of your speakers.
ie: Loud, bass-heavy music will benefit most, particularly if your speakers are somewhat under-damped at resonance.
IMO, it's a worthwhile (and relatively miniscule) expense if it's recommended by the speaker manufacturer.

It's also a matter of your personal listening habits and experience; advanced audiophiles tend to listen very intently to high quality recordings in just the right environment with just the right equipment.
To them, the differences are usually quite obvious, entirely subjective, and completely mystifying to the rest of the world.

cheers

[zildjian]

Question. Is it possible to design a speaker such that the high frequency signal from both amp inputs go to the tweeters and same for the low frequencies to the woofers? A more sophisticated cross-over, perhaps, but wouldn't the power from both amps be utilized in that case?

Only if you bridged the output of two amplifiers together could this be done first of all, so two amps compatible with such bridging would be needed. Most external power amps aren't set up for that option. That's the only way to combine the output from two amps to one speaker woofer or tweeter. Then as you stated, an internal crossover in the speaker would channel the appropriate signal to each driver, which would work fine, but would be less efficient than using an active crossover prior to signal amplification and just designating each amp for each signal.

Don't know if the original poster's questions were actually addressed beyond saying biamping or wiring works or not.

http://sound.westhost.com/bi-amp.htm
This link is a pretty well written explanation if you want more information, and doesn't seem laced w/ snake oil. This horse has been beaten into bits time and time again on this forum (and others). A forum search for those threads should bring more input on the subject than you probably ever wanted if you want even more info and lot more opinions.

[mtrycrafts]

Brands do you see what you just started??? :D again...Brad

Hey, do you want a boring site here, or a dynamic one from time to time:D
Variety is a spice of life.:D

[mtrycrafts]

Well, Schmoe, I again have to disagree. Firstly, Paradigm still recommends biwiring on their speakers.

Well, disagreeing is great, can get things done, ironed out.
But, unfortunately, Paradigm this time has an empty basket of tricks, with no supporting evidence for it. And, they certainly equipped to test it properly, under bias controlled conditions.:D
I think, there are other factors at play at the marketing office mentioned by others:D

I may even encourage you to call their engineering department and see how they tested that recommendation in the manual.

[mike c]

I hate to tell you, John, If Paradigm recommends it then they are pandering to the religious high end crowd. Bi wiring not only does nothing, it can't do anything. The engineers at Paradigm know that just as well as I do. If someone were to use wire of such a small gauge that it affected speaker performance, the solution is to use a heavier guage wire rather than adding more wires.

One would get an identical result by using a heavier gauge wire. Biwiring has nothing to do with it.
The only reason I can think of that a speaker company would recommend biwiring is that it might make them seem more "high end" to some of their more gullible customers.:rolleyes:

;)

i think John was being humorous ... see the ;)

he DID say that bi-wiring was NOT absolutely ineffective. it was effective if the first wire was insufficient in gauge. e.g. a person has spools of gauge 20 wire ... rather than buying a new heavier gauge wire ... he can use his existing gauge 20.

[PENG]

If your goal is to play your system brain-meltingly loud, then active biamping might help. Biwiring does not merely do "very little", it does nothing whatsoever. (To see this clearly, simply sketch a wiring diagram.)

Joe, I also think that biwiring will not improve SQ (not audible to me anyway), but before you think you understand the theory behind it you may want to read up a little more. There are no shortages of articles on the www but some of them were written by people who really did not fully understand the basics of electrical theory. Some of them do include wiring diagrams but the mistakes in their explanations would be obvious to people who are knowledgeable in electrical theories. The internet is great for the most part but sometimes there is no substitute for text books.

snickelfritz did a good job in his post spelling out the key points/facts.

[mtrycrafts]

To them, the differences are usually quite obvious, entirely subjective, and completely mystifying to the rest of the world.
cheers

Of course it is quite obvious to them, it is subjective, after all. The mind is interesting when it comes to subjective evaluations, limitless capability to imagine.

By the way, when you bi-wire, you do have full frequency voltage at each passive filters and, you do have out of band current flow in each set of wires, all depending on the slop of the filters, so, I doubt it is a Zero EMF deal.

[snickelfritz]

we imagine something; we build it; we imagine a way to measure it; we now doubt the validity of our imagination in preference for the measurement devices we imagined.

Passive bi-amping results in zero-EMF leakage, since the lowpass and highpass networks are completely isolated from each other.

[MDS]

Passive bi-amping results in zero-EMF leakage, since the lowpass and highpass networks are completely isolated from each other.

Are they really? I think not. Both xovers will still see a full-range signal and filter out whatever frequencies they don't want to deal with - just as if you had one single connection.

With active bi-amping, you'd have a xover filter out the signals it doesn't want to deal with before it gets to the speaker's xover.

[OttoMatic]

Are they really? I think not. Both xovers will still see a full-range signal and filter out whatever frequencies they don't want to deal with - just as if you had one single connection.

Both crossovers will see the voltage, but will only draw the current necessitated by the circuit inside. Since current draw is different, power in each set of speaker cables is different. It's subtle, but it's there.

[gcmarshall]

my suggestion is to forget about biwire and biamping. instead, get some respectable 12 ga speaker wire (lowes, home depot, crutchfield, etc.) and run 1 wire to each speaker....play music and enjoy.

in my opinion, unless you have a money tree in your backyard and you have the ears of a bat with which you can detect fractions of a fraction of noise differences, your time and money are better spent elsewhere.

[Adam]

...unless you have a money tree in your backyard...

Actually, that's in my neighbors yard, but I have a Bud Light beer tree. We've worked out an arrangement.

I had considered bi-amping some new speakers (SVS, if I get them), but only because I will have spare channels in my new amp (IPS-1, if I get it). I wasn't actually going to buy anything extra just to do it, though. From the opinions here and the opinion of the speaker manufacturer (Ron at SVS), it seems like it wouldn't do me any good to bi-amp.

[mtrycrafts]

we imagine something; we build it; we imagine a way to measure it; we now doubt the validity of our imagination in preference for the measurement devices we imagined.

Passive bi-amping results in zero-EMF leakage, since the lowpass and highpass networks are completely isolated from each other.

Perhaps you can explain then what you mean by zero EMF leakage that apparently happens without bi amping and what are the caused audible detriments and benefits?

As to imagining, yes, perception can be imagine based. Hence, the dreaded DBT protocol to get accurate perceptions. Has this been done for bi-wiring? Where, by whom, results can be accessed where?
Also, what do you measure differently by bi-wiring?

[mtrycrafts]

Since current draw is different, power in each set of speaker cables is different. It's subtle, but it's there.

So what is the detriments of having different current draws in the wires? After all, it is all frequency driven current. You have different current draws at all the different frequencies passed, no matter what. Not sure what you are driving at.

[Kolia]

bi-wiring looks so much cooler! Like, "there's so much power going to these speakers, I need double the cables to handle it!" (From my 50W NAD T743 of course). :D

Just like the stickers on my car makes it go faster... :cool:

[snickelfritz]

Perhaps you can explain then what you mean by zero EMF leakage that apparently happens without bi amping and what are the caused audible detriments and benefits?

I guess the most concise way to express it would be to say that EMF is the conversion of resonances in the woofer motor to voltage.
If this voltage is fed into the high pass filter, it will modulate the source signal to some degree, and will, after being filtered by the highpass network, be reproduced by the midrange driver.

Since this voltage is not a part of the source signal it will degrade the quality of upperbass/lower midrange reproduction to some degree.
How much depends on the speaker design, and will vary with the type of program material you feed it.

The audibility of the degradation would also depend on the quality of the lower midrange/upper bass reproduction capabilities of your speaker system.
Major flaws in this range, due to placement or speaker design will probably swamp the effects of EMF. (you can't hear a whisper in a hurricane)
Speakers that have very smooth response in this range, and are properly positioned in the room to minimize ringing and coloration in this range, might be audibly degraded by EMF.

Connecting the lowpass and highpass networks to separate amplifiers will completely remove EMF as a variable in the performance of the crossover network, since the networks will then be electrically disconnected and will not interact.

[mtrycrafts]

I guess the most concise way to express it would be to say that EMF is the conversion of resonances in the woofer motor to voltage.
If this voltage is fed into the high pass filter, it will modulate the source signal to some degree, and will, after being filtered by the highpass network, be reproduced by the midrange driver.

Since this voltage is not a part of the source signal it will degrade the quality of upperbass/lower midrange reproduction to some degree.
How much depends on the speaker design, and will vary with the type of program material you feed it.

The audibility of the degradation would also depend on the quality of the lower midrange/upper bass reproduction capabilities of your speaker system.
Major flaws in this range, due to placement or speaker design will probably swamp the effects of EMF. (you can't hear a whisper in a hurricane)
Speakers that have very smooth response in this range, and are properly positioned in the room to minimize ringing and coloration in this range, might be audibly degraded by EMF.

Connecting the lowpass and highpass networks to separate amplifiers will completely remove EMF as a variable in the performance of the crossover network, since the networks will then be electrically disconnected and will not interact.


So, then, do I understand you correctly that you are indeed talking about Back EMF?
If so, then a lot has been written about that by knowledgeable folks on the net:

http://groups.google.com/group/rec.audio.high-end/msg/9e25180f03c7f4f9?q=author:DPierce%40world.std.com+ back+emf&start=10&hl=en&lr=&ie=UTF-8&rnum=12

http://groups.google.com/group/rec.audio.tech/msg/9febaf18ece9484b?q=author:DPierce%40world.std.com+ back+emf&hl=en&lr=&ie=UTF-8&rnum=4

http://groups.google.com/group/rec.audio.tech/msg/71ca95c6df065c24?q=author:DPierce%40world.std.com+ back+emf&hl=en&lr=&ie=UTF-8&rnum=1

http://groups.google.com/group/rec.audio.high-end/msg/5ac53c1befc02746?q=author:DPierce%40world.std.com+ back+emf&hl=en&lr=&ie=UTF-8&rnum=5

I don't think I will lose any sleep over this issue.