Bi-AMPing Speakers. Why not, Steve?

[Cliff]

Originally posted by Steve Hoffman


BI-AMPING is something I never do.....

Quoted from the bi-wire thread...


Could you explain why, Steve? I've switched to a bi-amp configuration, and I'll never go back. It made a huge improvement in my system. I can't hear any negative drawbacks. The amps both "track" the same...

[Metralla]

Are you doing this in a "passive" or "active" manner.

"Passive" amping means that the crossovers inside the speakers are being used.

Are you "vertically" biamping or "horizontally" biamping.

I'm confused by which name applies to which. Maybe you know.

In one technique, a single stereo amp is used for one speaker, with one channel operating the low frequency unit and the other channel operating the high frequency unit. You would need two identical amps with very, very close gain to pull this off

In the other method, a single stereo amp has one channel connected to one driver and the other channel connected to the corresponding driver on the other speaker. The advantage of this method is you could use a solid state amp for the bass and a tube amp for the high frequencies. This could take a lot of matching to get exactly right.

The other way is "active biamping" where the preamp goes to an active crossover and the power amps are connected to the drivers directly - no crossover is used in the speaker.

This method makes sense to me for a number of reasons. I believe that it would require some tweaking to the crossover points and slopes to mate the speakers and amps up. It'd be an effort to get right though.

All that being said, I prefer to (on each side) use one amp, one pair of wires and the crossover that the speaker designer created. ;)

[triple]

Originally posted by Metralla
In one technique, a single stereo amp is used for one speaker, with one channel operating the low frequency unit and the other channel operating the high frequency unit. You would need two identical amps with very, very close gain to pull this off

I believe this is called vertical bi-amping.

Goran

[Cliff]

Geoff, I use passive bi-amping. One stereo amp to power the sub section of each main, the other amp used to power the satellite sections of each main. I can't see any reason to use an external x-over. That to me, would be defeating the purpose of the R&D of the speaker manufacturer. Shouldn't they have the x-over points for each driver/section dialed in, no matter how much power is applied (as long as the amps are close in terms of power output)? I also went with the same make of amps, so "tracking" (gain) would be the same.

[Metralla]

Originally posted by Cliff
I can't see any reason to use an external x-over. That to me, would be defeating the purpose of the R&D of the speaker manufacturer.
It's not just external - it's active; an active crossover is before the power amps. In theory, the crossover can be more accurate because it's working with line level, though I don't think that this is key. There should be fewer losses and the amplifier control of the motor on the low frequency unit should be far better. It would take a lot of adjustment of crossover points and slopes to get the whole business working together.

But it's been done.

In the early '80s there was the famous triamped Naim - Linn Isobarik combination. I never heard one - never saw one, in fact.

I'm sure there are some clever audiophiles out there with hand tuned kick-arse active systems.

[Highway Star]

My system is bi-amped using 2 different tube amps and I'm quite satisfied with the results. I too am using the internal crossovers in my speakers (3-way Infinity IL-40s, which are bi-wirable/ampable). The 4" mid/s and 1" tweeter/s are powered by a 35/wpc Wright Audio P-75 using 2 duets of big bottle EH 6CA7's. The 8" woofer/s are powered by a 100/wpc Music Reference RM-9 using 2 quartets of the same type 6CA7's.

The nice thing about the RM-9 is the 3-way feedback sensitivity switch. I use it on the lower setting and it behaves like a solid state somewhat for the woofer, yet is still nice and tubey. It all works quite well together, but I can understand the 'tricky-ness' of bi-amping, and why some might not be too fond of going that route.

I do like the IL-40's, although I feel like there could be better components used in the X-overs, and maybe higher quality tweeters.

[Taurus]

Speaking of biamping...........

Powered Advent speaker (http://fisherdoctor.com/advents.html)

(nope, no plastic computer speakers here!)

This is another cool reason I hope Advent is someday "reborn".

[T]

[Gary]

Have you heard that, Taurus? Does it sound different? Looks.... weird and interesting.

[-=Rudy=-]

Originally posted by Gary
Have you heard that, Taurus? Does it sound different? Looks.... weird and interesting.

It looks like it's 70's vintage, back when Advent had those rounded corners. This might be one to watch for at the thrift shops and garage sales. Or for twice as much money on eBay. :laugh:

[Gary]

I have a pair - not powered, though. It was my first "serious" pair of speakers...

.......... (singing) Memooories, may be beautiful and yet...... misty coloured memorieeeesss, of the way we wereeeeee...... :love: .....

[thegage]

The way I understand it, some people argue that passive bi-amping is not worth it because there is still interaction between the high/low (or high/mid/low) sections of the passive crossover, hence, for optimum performance active bi-amping is preferred. There is also the problem of matching amp sensitivity. Can't say about the performance, however, I passive biamp and find it very worthwhile. What I like best about it--apart from the gains in system headroom--is that in my setup I have the ability to quickly adjust bass levels--if I want to "party out" it's a quick turn of the gain knobs.

John K.

[Taurus]

Gary: nope, never got to hear those Advents but do remember some magazine testing them waaaaaay back and giving them a good review. If I recall correctly, it said the woofer amp generated 60 watts, and the tweeter amp 25 watts. This was equivalent to a normal (external) amplifier generating 125 watts because each amp was customized for its particular driver & because active crossovers were used, there were no inefficient passive crossover parts to soak up power (especially the inductors >>> those coils of wire; & resistors).

Rudy: the big Advents with rounded "bullnose" solid walnut front trim were made all the way to around 1985 but used a 1" parabolic mylar dome tweeter in place of the fried egg version. In fact, I still have a brochure in a box somewhere for them from 1983. It refers to them I think as the model "5012". Also pictured in there was a golden oak version of this speaker with the same tan grill--I have never seen one of these in person though. But it was quite pretty.

The brochure also described & pictured a budget version of this speaker. It used the same drivers but: used an @30% smaller cabinet; no real wood veneer; barely rounded front but not solid wood anymore; and I think it said it used a simpler crossover. Kinda frumpy looking but still fits in with most furniture styles, though they are pretty short so I would use a stand with them.

Biamping with an external/active crossover would be a great idea........if the active crossover was designed by the same designer of that speaker. Otherwise I personally wouldn't attempt such a system. The large majority of drivers don't behave perfectly & most importantly, don't blend together perfectly. A crossover can be used to minimise these problems BUT it takes technical know-how, a good ear and patience to properly "tune" a crossover to do this. In other words, when bypassing the built-in crossover of a speaker you better know what you are doing! Actually, a crummy crossover can ruin the sound of the best drivers available, while a good one can turn a set of humble drivers into an acceptable sounding system. That's why I don't automatically dismiss a budget-priced speaker; I've found some quite decent sounding ones among the truly junky ones.

[T]

[Clay]

Biamping with an external/active crossover would be a great idea........if the active crossover was designed by the same designer of that speaker.
I am bi amping.
1000 Watts for the woofers 10" ESS 1/4 wave length transmission line
60 Watts for the tweeters. ESS AMT
Electronic active crossover made by Speaker manufacture - ESS

Can get over 105db sound pressure level.

C20>ESS electronic crossover> Dynaco st 70 >700hz >ESS 500A <700hz

I have a few other crossovers to play with like a AR EC2 tube unit, I added the Caps to cross at 800Hz and a Pyramid 3 way I used until I could find the ESS.

[James Glennon]

Originally posted by Cliff
Geoff, I use passive bi-amping. One stereo amp to power the sub section of each main, the other amp used to power the satellite sections of each main. I can't see any reason to use an external x-over. That to me, would be defeating the purpose of the R&D of the speaker manufacturer. Shouldn't they have the x-over points for each driver/section dialed in, no matter how much power is applied (as long as the amps are close in terms of power output)? I also went with the same make of amps, so "tracking" (gain) would be the same.

I have two mono power amplifiers, with two volume controls on the preamp.

Left speaker (bi-wired) driven by one mono amplifier.
Right speaker (bi-wired) driven by one mono amplifier.

I am led to believe this is vertical bi-amping, I don't think I would be too keen for one amplifier to drive the bass speaker and the other to drive the tweeters.

Am I mad?
JG

[Vinyl-Addict]

Originally posted by James Glennon


I have two mono power amplifiers, with two volume controls on the preamp.

Left speaker (bi-wired) driven by one mono amplifier.
Right speaker (bi-wired) driven by one mono amplifier.

I am led to believe this is vertical bi-amping, I don't think I would be too keen for one amplifier to drive the bass speaker and the other to drive the tweeters.

Am I mad?
JG

You're not mad John. :) You are not bi-amping, you are just bi-wiring. To bi-amp using monoblocks, you would need 4.
1 for the upper freq. left speaker, 1 for low freq. left speaker.
1 for the upper freq. right speaker, 1 for low freq. right speaker.
Hope this helps. :)

[KeithH]

I have a passive bi-amp set-up, and I believe it would be called horizontal bi-amping. Here is what I have:

* Speakers: Totem Arro floorstander

* Integrated amp: NAD C 370 driving the tweeters on each speaker

* Power amp: NAD C 270 driving the drivers on each speaker

The C 370 and C 270 are gain-matched, and NAD did this specifically to facilitate bi-amping. They share the same amp section. As a result, I suppose I could try vertical bi-amping, but I'm not sure there would be a benefit.

I ran the Arro speakers with just the C 370 integrated amp for six months before bi-amping with the C 270 power amp. Adding the second amp made a significant difference in detail, soundstage, everything. Now, I'm sure I could have gotten better results had I replaced the C 370 with a more expensive integrated amp than by adding the power amp, but I got a good deal on the power amp and have been thrilled with the results.

[James Glennon]

Originally posted by Vinyl-Addict


You're not mad John. :) You are not bi-amping, you are just bi-wiring. To bi-amp using monoblocks, you would need 4.
1 for the upper freq. left speaker, 1 for low freq. left speaker.
1 for the upper freq. right speaker, 1 for low freq. right speaker.
Hope this helps. :)

Going by the following information I am bi-amping, but I stand corrected!

The second method of biamplification is known as the vertical configuration. This differs from the standard method in how the output of the two power amps is applied. In the vertical biamp, one amp is used to power only the left speaker and the second for only the right speaker. For this arrangement, the use of identical amplifiers is imperative.

In this case, each amplifier will still receive two channels of information from the preamplifier, but they will both be the same. The amplifier dedicated to the left speaker will now receive a pair of left-channel outputs from the preamplifier to feed both its right and left channel. The second amplifier, dedicated exclusively to the right speaker, will then receive a pair of right-channel outputs from the preamp for both its left and right input. This can be achieved in the same manner as used in the standard configuration, but by simply changing how the two patch cables are connected to the Y-adapters at the back of the preamp.

You then use each amplifier to run its own speaker rather than having the tweeters driven by one amp and the woofers by another. You would, for example, use the left output of the left amp to drive the left speaker’s highs and the right channel of the left amp to drive the left speaker’s lows. The right side being a mirror image of the left. No, it is not necessary to use the left channel for highs and the right for lows, I simply chose them in order to describe the hook-up.

This method has a distinct advantage over the standard configuration. Cross-talk (the tendency for one channel to "bleed through" to the other and thereby cause distortion) in the power amplifiers has effectively been eliminated. Both channels of each amplifier see identical information, so even if there is any kind of spurious leak-through of audio between left and right, because it is the same signal, it cannot create harmonic or inter-modulation distortions. This configuration offers the highest potential for left and right separation available from a biamplified setup.

JG

[grumpyBB]

Originally posted by James Glennon


Going by the following information I am bi-amping, but I stand corrected!

You have to use STEREO amps, not mono, for that to work.

You'd have to have 2 stereo amps driving the 2 speakers. On each amp one channel would be driving lows, the other channel driving highs.

[James Glennon]

Originally posted by grumpyBB
You have to use STEREO amps, not mono, for that to work.

You'd have to have 2 stereo amps driving the 2 speakers. On each amp one channel would be driving lows, the other channel driving highs.

I STAND CORRECTED AGAIN!

One amplifier driving the lows and the other amp driving the high, is referred to as 'horizontal' bi-amping.

The second method of biamplification is known as the vertical configuration. This differs from the standard method in how the output of the two power amps is applied. In the vertical biamp, one amp is used to power only the left speaker and the second for only the right speaker. For this arrangement, the use of identical amplifiers is imperative.

Each power amp is being fed (L+R signals) as I said in my earlier post, my preamplifier has two volume controls with stereo being fed to both mono amps.

Each amplifier has 4 binding post with one set of speaker cables going to the tweeter and the other set to the woofer (bi-wiring).

I was advised strongly against using one amplifer to drive both tweeters and the other to drive both woofers.

I am only trying to get to the bottom of this thread as to which is the best way, not trying to prove I am right!
JG

[grumpyBB]

Originally posted by James Glennon

I was advised strongly against using one amplifer to drive both tweeters and the other to drive both woofers.
You can do it either way, it depends on what you're going for. With horizontal biamping you could use a solid state amp for the woofers and a tube amp for the mids/highs. Of course trying to find 2 different type amps that sound similar could be difficult.

The main advantages I see for vertical biamping are this:

1) shorter speaker cables since I put my amps right next to the speakers

2) Better seperation. Each amp is only being fed either the left or right signal. No chance for crosstalk internally.

3) Each amp is being driven similarly. Each amp has one channel driving the woofer and one the other driving the mid/tweet. Both power supplies are only being required to do so much work. With horizontal biamping one amp is working it's butt off trying to drive the woofers and the other amp is loafing along doing only the higher frequencies.

[James Glennon]

Originally posted by grumpyBB
You can do it either way, it depends on what you're going for. With horizontal biamping you could use a solid state amp for the woofers and a tube amp for the mids/highs. Of course trying to find 2 different type amps that sound similar could be difficult.

The main advantages I see for vertical biamping are this:

1) shorter speaker cables since I put my amps right next to the speakers

2) Better seperation. Each amp is only being fed either the left or right signal. No chance for crosstalk internally.

3) Each amp is being driven similarly. Each amp has one channel driving the woofer and one the other driving the mid/tweet. Both power supplies are only being required to do so much work. With horizontal biamping one amp is working it's butt off trying to drive the woofers and the other amp is loafing along doing only the higher frequencies.

You say that you put your amps close to your speakers so as to have short run speaker cables.

What length are your interconnects?

I have read that in the USA, people go for longer interconnects and shorter speaker cables.

Not so in Europe, I believe it is very much frowned upon.

Many thanks for the interesting posts!
JG

[sprocket]

And here I thought bi-amping meant my preamp was seeing both tube and solid state amps.

[Gary]

That's double dating, Sprocket! :D

Fascinating thread. Some amps were not meant for bi-amping. Like my McIntosh 240 so I cannot run inefficient speakers.

Still, there are other rooms in my place that seem to be void of stereo systems..... ;) Now if I can only convince the beautiful wife... :eek: