Who Bi-Amps their speakers? Why? How?

[herbu]

This is an area I never really considered. My towers are recommended for 20-300w. I feed them from a 200wpc amp. They have 2x 6" woofers, 2x 5" mids, 1x 1" tweeter, and can be bi-amp'd. I have their crossover set at 80Hz, and have 2 nice subs. I do not bi-amp them, and have never really thought about it... until lately.

I never feel like I'm running out of juice at high volume. Bass sounds good w/ subs getting LFE+Main.

Who bi-amps, and why?
Is it because your normal L/R speaker signal isn't strong enough for all the drivers?
Is it for separate control of the woofers?

If you bi-amp, what do you send the woofers? Just LFE? Full range L/R w/ a low pass filter?

Thanks for any help. Trying to get a little understanding of when, why and how you would do this.

 

[rojo]

I bi-wire, simply because my AVR has the capability and my speakers are bi-wireable. I haven't tried them with a single cable pair, but I doubt I'd be able to tell any difference. I do it because it costs me nothing extra and it gives me a warm fuzzy to do so.

I also read somewhere that there's some sort of resonance feedback dark sorcery that can travel from the midbass driver to the tweeter and cause an infinitesimal amount of distortion or something, and that having the signal travel a long length of wire reduces such treachery. I don't really believe it matters, though, to be honest.

OTOH, bi-amping implies bypassing the speaker's passive crossover and using actively high-passed signal to the tweet and low or band-passed signal to the mid. That sounds like a pretty scary undertaking to me, so I'd never consider bi-amping.

 

[AcuDefTechGuy]

Most audiophiles only bi-amp if it is ACTIVE. Most speakers are passive. So even if they come with bi-wire or tri-wire speaker binding posts, it doesn't really do much to passive bi-amp. These speakers come with jumper cables or metal brackets. But even if you remove the jumpers, the bass, midrange, and tweeter are usually NOT completely separated in these passive speakers.

My Linkwitz Orion towers are actively quad-amped. That's because they are designed that way.

Now the XTZ Divine towers can be either passive (jumpers in place) or active (jumpers removed). They are designed so that if you remove the jumpers to the bass, the bass is completely separated from the rest of the speakers. If you remove the jumpers to the midrange, it will become completely separate. Same with the tweeter.

Speakers like the RBH SX-8300, SX-6300, T30, SX-T2, SX-T3, and Status Acoustics 8T can be have the bass section active. When you remove the jumpers to the bass, the bass becomes completely separate from the rest of the speaker. Thus you can bi-amp the towers. Actually the SX-1010 can be actively bi-amped. So you could Tri-amp the SX-T2 = passive single-amp the treble/midrange + active bi-amp each of the 10" driver of the SX-1010.

The SX-T3 can be quint-amp = single-amp the treble/midrange + quad-amp the four 10" woofers.

I only see the advantage of bi-amp if it is done to the bass.

 

[j_garcia]

I do not. Tried it. Heard no benefit over just dumping the appropriate amount of power on the speaker as a whole. Tried it with some Mordaunt Short bookshelfs and some Studio 20s. If you REALLY want to try it out, be my guest, but I think you getting to the "thought about it" stage is sufficient at this point.

Where I could possibly see some benefit would be in having completely separate power supplies for each section of the speaker in a bi-amp setup. That would mean separate amps not sharing a power supply for each section, so potentially meaning each channel would be a monoblock. Horizontal vs vertical might be worth trying too, to have a more balanced load on each amp with stereo amps, but then we may as well get into the whole active aspect and we're in a whole new ballpark.

 

[Swerd]

My towers are recommended for 20-300w. I feed them from a 200wpc amp. They have 2x 6" woofers, 2x 5" mids, 1x 1" tweeter, and can be bi-amp'd. I have their crossover set at 80Hz, and have 2 nice subs. I do not bi-amp them, and have never really thought about it... until lately.

With powered subwoofers and a 200 wpc amp driving your towers, I see no need to divide it's job among two or more amps.

Passive bi-amping disconnects a speaker's internal passive crossover from one network into separate networks. Do your towers have two sets of binding posts? If so, you probably can separate the 6" woofers from the mid range/tweeter networks. But because you already use subwoofers and have a potent amp, I see no added benefit from doing this.

Active bi-amping requires bypassing a speaker's internal passive crossover. An active (meaning it is actively driven by external electric power) crossover must be substituted upstream from the amplifiers. This is commonly done between a preamp/processor and and an amplifier. Usually these active crossovers are programmable, requiring that you know how to reproduce the functions of the speakers original passive crossover. This is easier said than done. Remember that bypassing the crossover puts your tweeters at risk of failure, and probably voids any warranty that came with your speakers.

There are people who successfully do this, but I see little benefit unless the speakers' original crossovers were poorly designed, and the owner did better with programming the active crossovers.

If you are using separately powered subs, you are probably already bi-amping. Your subs operate at 80Hz and below. Do you run your towers at full range, or at 80Hz and above? If you assign this division using a receiver or a preamp/processor, you are actively bi-amping.

I do not. Tried it. Heard no benefit over just dumping the appropriate amount of power on the speaker as a whole. Tried it with some Mordaunt Short bookshelfs and some Studio 20s. If you REALLY want to try it out, be my guest, but I think you getting to the "thought about it" stage is sufficient at this point.

+1 Listen to the man!!

 

[AcuDefTechGuy]

Do your towers have two sets of binding posts? If so, you probably can separate the 6" woofers from the mid range/tweeter networks.

It depends on crossover network design. It seems in most passive systems, even when you remove the jumpers, the woofer is not completely separated from the midrange and tweeter. That is why with most passive systems, the only way you can even active bi-amp is if you completely remove or bypass the internal XO and install your own.

 

[Swerd]

It depends on crossover network design. It seems in most passive systems, even when you remove the jumpers, the woofer is not completely separated from the midrange and tweeter. That is why with most passive systems, the only way you can even active bi-amp is if you completely remove or bypass the internal XO and install your own.

I don't follow what you're saying. Removing the jumper does not disconnect any of the drivers from their respective crossover networks.

Yes, if you want to substitute the passive crossovers with external active crossovers, you must disconnect each driver from the passive network board, and you must disconnect the binding posts on the rear of the cabinet from the board.

In the speakers where I've looked inside, removing the jumpers disconnected the woofer and its crossover network from the tweeter and it's crossover network (in a 2-way). In a 3-way speaker, it gets more complicated to talk about, but the concept is the same.

 

[Swerd]

I found some diagrams, borrowed from this article http://www.audioholics.com/frequent-questions/the-difference-between-biamping-vs-biwiring

Passive bi-amping with passive crossover inside speaker cabinet. Note that the HF and LF networks are not linked physically or electrically. In most speakers with two pairs of binding posts, removing the jumper electrically disconnects the HF and LF networks.

Active bi-amping. In this diagram, the internal crossovers are not shown. They can be removed or bypassed.

 

[AcuDefTechGuy]

I don't follow what you're saying. Removing the jumper does not disconnect any of the drivers from their respective crossover networks.

Yes, if you want to substitute the passive crossovers with external active crossovers, you must disconnect each driver from the passive network board, and you must disconnect the binding posts on the rear of the cabinet from the board.

In the speakers where I've looked inside, removing the jumpers disconnected the woofer and its crossover network from the tweeter and it's crossover network (in a 2-way). In a 3-way speaker, it gets more complicated to talk about, but the concept is the same.

I think the question is, if you just remove the jumpers, can you actively bi-amp the woofers or is it still passive?

 

[Swerd]

I think the question is, if you just remove the jumpers, can you actively bi-amp the woofers or is it still passive?

Here is how I understand it:

If you just remove the jumpers, you can bi-amp passively. You also need two amps .

If you remove the jumpers and physically remove the internal passive crossover boards (or electrically bypass them), you can actively bi-amp. You also need two amps and an external active crossover .

Explaining all this has me exhausted – especially when it isn't worth doing.

 

[AcuDefTechGuy]

If you just remove the jumpers, you can bi-amp passively. If you remove the jumpers and physically remove the internal passive crossover boards (or electrically bypass them), you can actively bi-amp.

We're on the same page then.

Here's the thing. Some speakers are set up so that when you remove the jumpers, you can actively bi-amp without having to do anything to the internal XO. Examples include RBH towers, XTZ Divine tower, NHT Classic 4 tower.

With the RBH & NHT, you can active bi-amp only the woofers. With the XTZ Devine, you can active tri-amp the woofer, midrange, and tweeter.

 

[GranteedEV]

Who bi-amps, and why?

Me, on the speakers linked in my sig. Why? Because the tweeter's impedance chart and frequency response are pretty damn tough to shape using only cut filters that are impedance-dependant (passive crossover), especially near the crossover frequency. I'd prefer not to bi-amp though, because the tweeter is very revealing of electronics noise due to its high sensitivity - thus having ten+ db of resistive attenuation instead of the amp directly coupled to the driver would be ideal. My goal is to spend a lot of time switching from (active) Bi-amping to (passive) mono-amping. Or maybe a hybrid crossover a la John Kreskovsky where the tweeter/midrange crossover is handled passively but then further EQ is used to shape response globally.

Is it because your normal L/R speaker signal isn't strong enough for all the drivers?

I think some wimpy two-watt amp is "enough" for all the drivers. Once a crossover is in place, the amp is not exactly sending the same power to all drivers. The filters serve to split and direct the power accordingly.

Is it for separate control of the woofers?

No.

If you bi-amp, what do you send the woofers? Just LFE? Full range L/R w/ a low pass filter?

The woofers receive the signal I intend for htem to receive - this includes a bass shelf filter below 300hz to lift response below the baffle step, a very slight 2db notch at 1.6khz to tame the paper cone a smidge, and the low-pass filter.

My advice: unless the speaker design calls for it - you don't need to bi-amp. Most speaker designs do not call for it. If it contains a passive crossover and the Z-chart in the crossover region is well-controlled, then so-called advantages of bi-amping are academic at best, assuming they even exist.

 

[herbu]

I bi-wire, simply because my AVR has the capability and my speakers are bi-wireable.

Thanks for all the feedback guys. Sounds like bi-amping may require expertise beyond mine.

Now to bi-wire, how do you do that? My AVR has one pair of Left Front outputs, and one pair of Left Front preouts. I use the preouts thru an amp, and don't use the Left Front speaker outputs. To bi-wire, would I run the speaker outs to one set of terminals, and the pre-amp/amp outputs to the other set of terminals?

 

[Swerd]

Thanks for all the feedback guys. Sounds like bi-amping may require expertise beyond mine.

Now to bi-wire, how do you do that? My AVR has one pair of Left Front outputs, and one pair of Left Front preouts. I use the preouts thru an amp, and don't use the Left Front speaker outputs. To bi-wire, would I run the speaker outs to one set of terminals, and the pre-amp/amp outputs to the other set of terminals?

Bi-wiring is much simpler.

Run two sets of speaker cables from the left front speaker outputs to the left front speaker terminals. Do the same for the right channel. Yes, that would be two sets of cables for each speaker.
If your reaction to this is: WHAT , stop right there. There is no good reason to do this as there is no audible benefit. It will use twice as much speaker cable, and as you might imagine, it can make for a tangled mess.

I offer some polite advice: When it comes to audio, don't believe everything you read. Both bi-wiring and bi-amping are highly controversial topics on audio forums, but they are good examples of why the audio industry is troubled by so much voodoo and snake oil. There simply is no evidence that either of these "tweaks" has any audible benefit.

 

[rojo]

Thanks for all the feedback guys. Sounds like bi-amping may require expertise beyond mine.

Now to bi-wire, how do you do that? My AVR has one pair of Left Front outputs, and one pair of Left Front preouts. I use the preouts thru an amp, and don't use the Left Front speaker outputs. To bi-wire, would I run the speaker outs to one set of terminals, and the pre-amp/amp outputs to the other set of terminals?

If you look at the back of my receiver:

You'll notice that the high level outputs for "Surround Back" have a small label beneath reading "Assignable". In my AVR's on-screen software (and via its web interface) I can reassign the assignable outputs to mirror the output of the front main LR. So I've got a wire pair going from my main L to the midbass binding posts on my main L speaker, and another wire pair going from the surround back L to the tweeter binding posts on my main L speaker. The same full-range signal (80Hz HPF notwithstanding) gets pushed from both outputs, so I still rely on the speaker's internal passive crossovers.

If your AVR doesn't have that feature, I don't think you're missing much. It's essentially like using a 10-foot jumper cable. As Swerd suggests, the same exact effect can be attained by running two pair of lamp cord from a single speaker out. I should note that my AVR manual refers to this connection method as bi-amping, but it's not really.

But my AVR has the feature and it gives me a warm fuzzy to use it, for no other reason than to say I did.

 

[Swerd]

If you look at the back of my receiver…

If your AVR doesn't have that feature (ie. assignable speaker outputs), I don't think you're missing much. It's essentially like using a 10-foot jumper cable. As Swerd suggests, the same exact effect can be attained by running two pair of lamp cord from a single speaker out. I should note that my AVR manual refers to this connection method as bi-amping, but it's not really.

But my AVR has the feature and it gives me a warm fuzzy to use it, for no other reason than to say I did.

I understand "warm fuzzy" feelings . And I'm also glad you understand, despite what the receiver manufacturer says in the manual, that this isn't bi-amping.

It bothers me (to the point of being a pet peeve) that receiver manufacturers say this in their manuals. I believe it is misleading. Even though you do understand this, for the benefit of other readers, I feel compelled to emphasize that reassigning speaker outputs on a multi-channel receiver is not bi-amping.

The real benefit of bi-amping is having two amplifiers with two separate power supplies. Think of an amplifier's power supply as the engine of a car, and the power output sections as the car's transmission. (I usually wince at automobile analogies, but if you don't push it too far, it helps to think about this.) If you go from 2-wheel drive to 4-wheel drive, you still have the same engine power. Similarly, if you reassign power output channels in a multi-channel receiver, you haven't added any power.

 

[AcuDefTechGuy]

Sounds like bi-amping may require expertise beyond mine.

Not really. But it's probably a good idea to only do things (like bi-amp) if it would actually enhance the sound.

Let's look at this bi-amp from another perspective, which Swerd already mentioned.

Let's say Tower = Monitor + Subwoofer = modular Tower.

So if you are using a monitor + subwoofer, you are "bi-amping" a modular tower. You connect the monitor to the AVR as usual. You connect the LFE/Sub output from your AVR to the Amp section of the Sub. The Amp section of the sub then powers the Sub. You are bi-amping a "modular" tower system.

Now if you have the RBH SX-T2 (which = SX-T1 + SX-1010), this is how you actively bi-amp:
1) Connect the SX-T1 to the AVR.
2) Connect the LFE/Sub output of the AVR to an External amp (with volume control).
3) Connect the External amp to the SX-1010.

You are now actively bi-amping the SX-T2. Same way with the SX-8300. Remove the jumpers. The SX-8300 is now a monitor + subwoofer. This is how it was designed.

 

[lsiberian]

Bi-amping is for kids. Tri-amping is where it's at these days. My main speakers are bipolar and actively triple amped. I do think you can improve speakers by going active, but it's a lot more work to setup and not for those who lack the patience and skill to do it well. And if you already have that you may as well build the boxes too.

 

[herbu]

Run two sets of speaker cables from the left front speaker outputs to the left front speaker terminals.

It's been a long time since I went to school for this, but isn't that a parallel connection... and wouldn't it cut the impedence the AVR sees in half? So a normally 6ohm speaker would be seen as 3ohms? And wouldn't that stress the AVR more?

the high level outputs for "Surround Back" have a small label beneath reading "Assignable"

I think my Denon X4000 can do that too. And if somebody wanted to, that would seem maybe a safer solution than wiring in parallel. Right?

Now if you have the RBH SX-T2 (which = SX-T1 + SX-1010), this is how you actively bi-amp:
1) Connect the SX-T1 to the AVR.
2) Connect the LFE/Sub output of the AVR to an External amp (with volume control).
3) Connect the External amp to the SX-1010.

That makes a lot of sense for a speaker w/ a true subwoofer like the T2. For my Aperions, not so much.

So, here's what I'm getting:
1) There may or may not be some audible benefit from bi-wiring
2) Bi-amping can be useful for individual control of highs/mids/lows
3) Speakers like my Aperions provide bi-wire/amp connections more likely as a marketing tool than a useful or necessary feature

Is that about right?
Thanks!

 

[rojo]

It's been a long time since I went to school for this, but isn't that a parallel connection... and wouldn't it cut the impedence the AVR sees in half? So a normally 6ohm speaker would be seen as 3ohms? And wouldn't that stress the AVR more?

Running a midbass driver with a tweeter in parallel doesn't have the same load demand as running two midbass drivers in parallel. The load drawn by a tweeter is negligible. Also given that the tweet has a passive HPF and the mid has a LPF, your AVR will still see the speaker system combo pair thingy as a single 6 or 8 or whatever ohm demand. What Swerd is describing is effectively no different from simply using jumpers on the speaker's binding posts. It just uses more wire.

I think my Denon X4000 can do that too. And if somebody wanted to, that would seem maybe a safer solution than wiring in parallel. Right?

I think no more or less safe, really, unless you want to be obsessive and include the possibility that you could accidentally mix up the polarity of your wires.

That makes a lot of sense for a speaker w/ a true subwoofer like the T2. For my Aperions, not so much.

So, here's what I'm getting:
1) There may or may not be some audible benefit from bi-wiring
2) Bi-amping can be useful for individual control of highs/mids/lows
3) Speakers like my Aperions provide bi-wire/amp connections more likely as a marketing tool than a useful or necessary feature

Is that about right?
Thanks!

1. Probably no audible benefit, but it'll make you feel good.
2. Yep.
3. Pretty much, yeah. Bi-wire connections do offer a measure of flexibility, but taking advantage of that flexibility is a bit of a pain in the ass.