Bi-amp, bi-wire, passive crossover & active crossover interaction

[mjgraves]

My background is pro audio, where bi/tri-amp is well known. It requires an active crossover, feeding separate amplifiers, such that each speaker (sub/woof/tweet) receives only it's intended frequency range.

I see quite a few consumer loudspeakers with two sets of terminals that default to being bridged. Presumably these include passive crossovers so they can be used with a single amplifier.

If the user removes the bridges, which are external to the cabinet, they can support bi-wire (IMHO, pointless except to sell more fancy speaker cables) or bi-amp operation. However, the passive filters in the cabinets must remain in place.

I think such speakers are inherently problematic. Removing the bridge separates the woofer & tweeter feeds, but does not take the passive crossover out of circuit. Each path must still be passively filtered.

This restricts what you can do with an upstream active crossover. You can't really alter the xover frequency since the passive xover will stay fixed.

Or am I missing something? Is there some way to eliminate the passive crossover in such speakers?

 

[Plcamp]

I don’t see any advantage to biamping such systems.certain speakers (such as OB) have giant differences in power requirements for bass vs hf, so there may be some theoretical advantage in that case, but the real advantage is getting cross and eq control before the amps.

The picture is the “Biampable” crossover supplied with the PAP Trio 15 TB, with adjustable configuration for biamping. In this case my AVR can drive the TB1808 fullrange but not the min 3.7 ohm twin 15” woofers. So it ‘makes sense’ somewhat to biamp in this case, but better is a high quality dsp and bypass the cross entirely.

 

[levimax]

Here is a very good article https://sound-au.com/bi-amp.htm

 

[DVDdoug]

If the user removes the bridges, which are external to the cabinet, they can support bi-wire (IMHO, pointless except to sell more fancy speaker cables)

Correct!

I think such speakers are inherently problematic. Removing the bridge separates the woofer & tweeter feeds, but does not take the passive crossover out of circuit. Each path must still be passively filtered.

This restricts what you can do with an upstream active crossover. You can't really alter the xover frequency since the passive xover will stay fixed.

I Agree!

 

[R Swerdlow]

My background is pro audio, where bi/tri-amp is well known. It requires an active crossover, feeding separate amplifiers, such that each speaker (sub/woof/tweet) receives only it's intended frequency range.

I see quite a few consumer loudspeakers with two sets of terminals that default to being bridged. Presumably these include passive crossovers so they can be used with a single amplifier.

If the user removes the bridges, which are external to the cabinet, they can support bi-wire (IMHO, pointless except to sell more fancy speaker cables) or bi-amp operation. However, the passive filters in the cabinets must remain in place.

I think such speakers are inherently problematic. Removing the bridge separates the woofer & tweeter feeds, but does not take the passive crossover out of circuit. Each path must still be passively filtered.

This restricts what you can do with an upstream active crossover. You can't really alter the xover frequency since the passive xover will stay fixed.

Or am I missing something? Is there some way to eliminate the passive crossover in such speakers?

Most pro audio involves moving a sound system from one location to another, and setting it up to suit the acoustics of a particular setting. This gets done again and again every time the sound system is moved to a different location. Pro audio sound technicians are supposed to know how to alter the active crossover filters to suit a location – while getting good results – without damaging the loud speakers. It makes sense to do this with fully adjustable active crossovers.

Home audio is different. Owners range widely in how well they understand designing or setting up crossover filters. Some are knowledgeable & experienced at this. And some are fools who are determined to damage their loud speakers. Most people fall somewhere in the middle. They mean well but are inexperienced at this.

I've only seen a few home audio speakers that had active crossovers with built-in amplification. They divided the active crossovers into two sections. One section allowed owners to equalize speaker outputs, but the fundamental details of the crossovers were locked, inaccessible to the owners. I certainly understand why home audio speaker makers would want to do that.

If you insisted on using an external active crossover, you could always bypass a speakers internal passive crossover. That would void the manufacturers warranty.

 

[mjgraves]

Most pro audio involves moving a sound system from one location to another, and setting it up to suit the acoustics of a particular setting. This gets done again and again every time the sound system is moved to a different location. Pro audio sound technicians are supposed to know how to alter the active crossover filters to suit a location – while getting good results – without damaging the loud speakers. It makes sense to do this with fully adjustable active crossovers.

Home audio is different. Owners range widely in how well they understand designing or setting up crossover filters. Some are knowledgeable & experienced at this. And some are fools who are determined to damage their loud speakers. Most people fall somewhere in the middle. They mean well but are inexperienced at this.

I've only seen a few home audio speakers that had active crossovers with built-in amplification. They divided the active crossovers into two sections. One section allowed owners to equalize speaker outputs, but the fundamental details of the crossovers were locked, inaccessible to the owners. I certainly understand why home audio speaker makers would want to do that.

If you insisted on using an external active crossover, you could always bypass a speakers internal passive crossover. That would void the manufacturers warranty.

My question was fundamentally about the relationship between the internal crossover and the dual binding posts offered on the cabinet.

Merely removing the bridging links does not in any way disable the passive crossover. I think this fact is not well understood/appreciated.

 

[HansHolland]

My question was fundamentally about the relationship between the internal crossover and the dual binding posts offered on the cabinet.

Merely removing the bridging links does not in any way disable the passive crossover. I think this fact is not well understood/appreciated.

I have been in home audio for more than 35 years in many ways. I think that they all (at least most) know that removing the bridging links does NOT disable the passive crossover. That is also NOT their aim. They want to use two times more loudspeaker cable that is promissed to do miracles.

And sometimes they even use an second stereo amp (or a third and forth mono amp). But that can give some little advantage if a single stereo amp cannot deliver enough current.

 

[Katji]

The picture is the “Biampable” crossover supplied with the PAP Trio 15 TB, with adjustable configuration for biamping. In this case my AVR can drive the TB1808 fullrange but not the min 3.7 ohm twin 15” woofers. So it ‘makes sense’ somewhat to biamp in this case, but better is a high quality dsp and bypass the cross entirely.

Nice. I used to see that guy at the OB Only group when I was on Fb. Nice design.

 

[Zek]

My question was fundamentally about the relationship between the internal crossover and the dual binding posts offered on the cabinet.

Only the input for the bass crossover and the tweeter crossover is physically separated.

Merely removing the bridging links does not in any way disable the passive crossover.

You're right.

 

[mjgraves]

I have been in home audio for more than 35 years in many ways. I think that they all (at least most) know that removing the bridging links does NOT disable the passive crossover. That is also NOT their aim. They want to use two times more loudspeaker cable that is promissed to do miracles.

And sometimes they even use an second stereo amp (or a third and forth mono amp). But that can give some little advantage if a single stereo amp cannot deliver enough current.

There can be a lot of advantages to bi/tri-amp. Electronic crossovers/DSP offer separate opportunity for refinement. The drivers and their associated amplifiers can be a more optimal pairing.

 

[DonH56]

Bi-amping 101: https://www.audiosciencereview.com/forum/index.php?threads/bi-amping-101.22817/

 

[HansHolland]

There can be a lot of advantages to bi/tri-amp. Electronic crossovers/DSP offer separate opportunity for refinement. The drivers and their associated amplifiers can be a more optimal pairing.

Yes, I know.
But I reacted on your "I think this fact is not well understood/appreciated." And that is about the "default" home audio situation.

I have the idea that the OP is flabbergasted by the stupidity of what all is going around in home audio. Has he already discovered the snake oil?

 

[mjgraves]

Yes, I know.
But I reacted on your "I think this fact is not well understood/appreciated." And that is about the "default" home audio situation.

I have the idea that the OP is flabbergasted by the stupidity of what all is going around in home audio. Has he already discovered the snake oil?

I am the OP. Like you I have been in home audio for decades. Pro audio & video for about 30 years.

It simply never occurred to me that the quad connectors on the back of some hi fi speakers, with shiny little links, were so poorly considered.

If you want to bi-amp a two-way speaker there should be no passive crossover components at all.

I'm well aware of all the snake oil that's out there. I appreciate the reference to MQA in your sig.

 

[Zek]

If you want to bi-amp a two-way speaker there should be no passive crossover components at all.

Then there must be an active crossover somewhere in front of amplifiers.

 

[DonH56]

15 or so years ago when I first read about "passive bi-amping" I assumed it meant speaker-level crossover components outside the boxes, then found out what they meant by it using AVRs and was somewhat dumbfounded. The marketeers latched on to the idea, manufacturers dutifully added the extra terminals because customers demanded it, and here we are. At least once a month I read a thread from someone who did not receive or lost the terminal jumpers and wants to know how to replace them. (They even make custom jumpers that go for up to $1k or so for a few inches of metal.) I am glad to see some speaker manufacturers are reverting to single terminals.

 

[mjgraves]

Then there must be an active crossover somewhere in front of amplifiers.

Absolutely. I never occurred to me that someone might "bi-amp" while retaining the passive xovers. That fails to deliver much of the potential flexibility of bi-amping.

 

[dfuller]

For the life of me, I can't figure out the point of it. It doesn't sidestep the usual issues of passive speakers, and it doesn't give you the benefits of actives.

 

[Holmz]

Here is a very good article https://sound-au.com/bi-amp.htm

And this as a 1/2 measure:

Bi-wiring Speakers: An exploration of the benefits -

(Bi-wiring Speakers) Bi-wireable loudspeakers have been available since at least the late 1980s and are now quite common. You can easily tell if your spea

www.qacoustics.co.uk

 

[wayneCravat]

Yikes, seems to me that all these questions and answers depend on what's inside the speaker, so general answers aren't possible. In a bi-amp configuration, there is no "crossover" happening, but something equivalent to a high-pass filter to the tweeter, and lo-pass to the woofer. When jumpered, whatever it is must act as a crossover. The details matter and would have to be provided by the speaker manufacturer, because there are many ways the above could be achieved. Quick searches for my Monitor Audio Bronze B1's turns up no such details so I have no idea what's inside.

 

[Doodski]

In a bi-amp configuration, there is no "crossover" happening, but something equivalent to a high-pass filter to the tweeter, and lo-pass to the woofer.

HUh? There is crossover action occurring in a bi_amp'd configuration. it's a different amp configuration but the same crossover.