Can biamping blow my speakers?

[damoncz]

Forgive the basic question but I am really baffled.

My setup:
I have a pair of KEF iQ9 speakers(rated 20 to 150 Ohm) and an Onkyo SR-607(7channel x 90 watts). Both speakers and amp are capable of biamping...

My question/problem:
If I biamp my speakers I am supplying 90x2 watts to each speakers...could it burn my speakers if I turn up the volume, since I am sending more power than the could endure? The question I am asking is it almost already happened..After I hooked them, immediately noticed that one of the tweeters on a speaker has gone silent..it simply didn't produce any sound above 2000 Hz. I RMAd that one and tomorrow I am getting the replacement. I don't want to burn this one with bi-amping! So please help!!

Thanks,
Damon

[GO-NAD!]

One of your tweeters immediately went silent? Do you mean before you turned up the volume? If that's the case, it wasn't because you overpowered the speaker. Is it possible that when you connected the speaker wire to the binding post that supplies that particular tweeter, that you might've shorted the wire, i.e. wire strands from the positive and negative touched each other?

[GO-NAD!]

Hi Damon, and Welcome to Audioholics. :)

NO, biamping speakers that are biampable from a biamp capable receiver like yours, will not blow your speakers. The only thing that can blow up is your ears. ;)

Bob

I agree, but that dosen't explain his dead tweeter...;)

[walter duque]

I bi-amp my center which is rated at 220 watts with 350 watts so far so good. I do play at very high volume. Should not be a problem for you unless you really overdrive them. I used to be worried about it too.

[bandphan]

get a bigger amp if you need more power:)

[TLS Guy]

Forgive the basic question but I am really baffled.

My setup:
I have a pair of KEF iQ9 speakers(rated 20 to 150 Ohm) and an Onkyo SR-607(7channel x 90 watts). Both speakers and amp are capable of biamping...

My question/problem:
If I biamp my speakers I am supplying 90x2 watts to each speakers...could it burn my speakers if I turn up the volume, since I am sending more power than the could endure? The question I am asking is it almost already happened..After I hooked them, immediately noticed that one of the tweeters on a speaker has gone silent..it simply didn't produce any sound above 2000 Hz. I RMAd that one and tomorrow I am getting the replacement. I don't want to burn this one with bi-amping! So please help!!

Thanks,
Damon

I think it likely that the biamping had something to do with it. It is not over powering per se, as you would be passive biampimg and the tweeter would just take the power it wants. So in fact when you were biamping you were actually adding only a watt of power to the speaker not 90 watts. So it is actually 90 + 1 Watt, as a tweeter will not draw more than a watt or two on music program.

Passive biamping is not of benefit, but as I have sated before provides opportunities for damage. Crossovers present highly inductive and capacitative loads to the amp, and it will be different for a very speaker.

The high pass section to the tweeter is a capacitative load mainly. Now it is far from uncommon for amps to become unstable and develop supersonic oscillations you can't hear with these types of loads. So it is possible that with that circuit and you amp under certain conditions, with the low pass filter connected to another channel, that a supersonic oscillation blew the tweeter or a crossover component.

I would forget about passive biamping. It is all potential risk and no benefit.

[TLS Guy]

^ About passive Bi-wiring?

No benefit, and it doubles the risk of a wiring error!

Here is what wrote about biamping recently. (http://forums.audioholics.com/forums/showthread.php?t=56379&page=2)

[TLS Guy]

Thanks for your very quick reply.

I'm only bi-wiring (passively) my center speaker, and I uses a Kimber Kable 8TC speaker cable, with 5 wires going to the two woofers (6.5" drivers), and 3 wires going to the tweeter. At the other end (my receiver), I just connect the full 8 wires to the single speaker's binding post.

It has been connected that way for quite a while now (over few years), and it sounds as fine (I think) as if it was connected by just a single speaker cable going to the center speaker (single-wiring), with the cross bars on, of course.

What's your take?

Thanks,
Bob

That is the whole point, it will not change the sound if you use two wires or eight.

[TLS Guy]

Oh, TLS Guy, can I also ask you a small favor?

Could you please check this very short thread (it's only 8 posts long), and give your pro opinion on the subject at hand. I did mentioned your name on my post (#5) of the ditto thread, because I knew that you were the right person to address this matter in the best way possible. Your expertise on speakers, amplifiers and several other components are of the most invaluable assets.

* Here's that thread: http://forums.audioholics.com/forums/showthread.php?t=56857

I really appreciate having someone like you in these Forums, here at Audioholics. For me, you are the true professional technical advisor on audio matters.

I lift my hat to you sir.

Bob

Speaker impedance specifications mean nothing! Speaker impedance curves are usually complex. However, narrow fronted speakers are going to drop their impedance below 400 Hz for diffraction compensation. For a common 2,5 way speaker, (two woofers one tweeter on top), two thirds of the power will go to the woofers where the impedance will be 4 ohms or less, except at the narrow tuning peaks. If a speaker has two or more woofers it is four ohms, no matter what the manufacturer says. Not only that, voltage and current are always out of phase to some degree, so the current draw will be higher than you would think.

Now transistors amps are limited in the rail voltage because of the breakdown characteristics of semiconductors. So to get power, impedance has to be 8 ohms or less. So an amp really has to be able to drive a four ohm load, or you will not get the power you think. Because of THX certification, receivers do not generally blow up with a four ohm load, but they can't increase current. So most receivers driving the vast majority of speakers on the market, are actually delivering half their rated power. The reason you don't see this as obvious, is because it is only a 3 db reduction in spl.

So if you have two amps of 100 watt power into an 8 ohm load, and one can not increase current as load impedance drops, and the other can. Then then the first amp will be a 50 watt amp driving most speakers, and the other will be a 200 watt amp. That is a significant increase in spl.

[TLS Guy]

Hmmm... Thicker wire (bigger gauge) would not make any difference?

About the woofer EMF going back to the receiver and infiltrating the tweeter coming back to it with some distortion or noise?
Is Bi-wiring preventing exactly that? And by the same way, benefitting by not allowing that back EMF to show up it's nasty nose at the tweeter end?

Am I missing something? Or is my understanding not correct?

Thicker wire is a different matter, and depends on the length of the run. 14 or 16 AWG is usually sufficient.

[TLS Guy]

I think it likely that the biamping had something to do with it. It is not over powering per se, as you would be passive biampimg and the tweeter would just take the power it wants. So in fact when you were biamping you were actually adding only a watt of power to the speaker not 90 watts. So it is actually 90 + 1 Watt, as a tweeter will not draw more than a watt or two on music program.

Passive biamping is not of benefit, but as I have sated before provides opportunities for damage. Crossovers present highly inductive and capacitative loads to the amp, and it will be different for a very speaker.

The high pass section to the tweeter is a capacitative load mainly. Now it is far from uncommon for amps to become unstable and develop supersonic oscillations you can't hear with these types of loads. So it is possible that with that circuit and you amp under certain conditions, with the low pass filter connected to another channel, that a supersonic oscillation blew the tweeter or a crossover component.

I would forget about passive biamping. It is all potential risk and no benefit.

There is another issue here that I should have pointed out. You can easily clip an amp that is delivering no power. If you give it enough drive and call for voltage greater than the rail voltage an amp will still clip and hard!

Remember with passive biamping both amps are producing the SAME signal at the output terminals. Distortion products are HF. Now the OP thought he could run his speakers at a higher volume than before, but he can't. He will drive his HF amp into voltage clipping. Now with the amp just connected to the High pass filter, it can unleash all its power delivering those distortion products to the tweeter.

As I think about it, this is probably the most likely reason for the OP's tweeter failure.

[bandphan]

As for me, I was more asking about the true benefit of bi-wiring.

none at all :)

[bandphan]

Bi-wiring improves clarity in loud passages by preventing the back EMF (electro-mechanical feedback) that is inevitably generated by the woofers from getting into and saturating the crossover for the mid and high drivers; it's only path is to go all the way back to the amplifier's speaker terminals and back down the other cables, which it cannot do against the electron flow from the amplifier in a bi-wired system.

So, again, TLS Guy and also Bandphan, my question is: Is Bi-Wiring has any benefit at all?

Bob

1 wire> divided into 4 leads>into 1 passive crossover = nothing. Take the terminal off the back of your speaker and look at the wiring. Regardless if you use the jumpers or the "bi wires" the resullt is the same.

[TLS Guy]

Bi-wiring improves clarity in loud passages by preventing the back EMF (electro-mechanical feedback) that is inevitably generated by the woofers from getting into and saturating the crossover for the mid and high drivers; it's only path is to go all the way back to the amplifier's speaker terminals and back down the other cables, which it cannot do against the electron flow from the amplifier in a bi-wired system.

So, again, TLS Guy and also Bandphan, my question is: Is Bi-Wiring has any benefit at all?

Bob

That is nonsense. Most passive crossovers pretty much eliminate the back EMF of a speaker reaching the terminals and therefore make the issue of the damping factor of an amp mute. When you bi wire you just have increased the resistance of the jumper slightly, nothing else. Bi wiring is 100% bogus and has no benefit what ever. Even is back EMF were an issue which it isn't, bi wiring would not change the equation.

In an active system, with the woofer directly connected by a wire of low resistance to an amp with decent damping factor, does keep the woofer under better control, slightly.

[mtrycrafts]

Forgive the basic question but I am really baffled.

My setup:
I have a pair of KEF iQ9 speakers(rated 20 to 150 Ohm) and an Onkyo SR-607(7channel x 90 watts). Both speakers and amp are capable of biamping...

My question/problem:
If I biamp my speakers I am supplying 90x2 watts to each speakers...could it burn my speakers if I turn up the volume, since I am sending more power than the could endure? The question I am asking is it almost already happened..After I hooked them, immediately noticed that one of the tweeters on a speaker has gone silent..it simply didn't produce any sound above 2000 Hz. I RMAd that one and tomorrow I am getting the replacement. I don't want to burn this one with bi-amping! So please help!!

Thanks,
Damon

Did you remove the shorting strap at the speakers?

[TLS Guy]

"That is nonsense"!!! :eek:

Thanks for the kind words. I appreciate the positive feedback. :rolleyes:

I should, however, clarify some of what I may not have explained correctly when I was talking about the subject with you.
Bi-wiring is an advantage due to the finite resistance of speaker cable, which is likely to be in the range of 10-100 times the output impedance of the power amplifier. This cable resistance can allow distortion products to appear on the cable, and enter other drivers in the speaker.
The reason this happens is that the impedance of a speaker voice coil is not linear. Distortion products which appear in the motion of the driver will, through back EMF (ElectroMotive Force), modulate any resistance which is present at the source. If those distortion products lie above the crossover frequency, they will become signals which can be reproduced by other drivers in the same box.
Bi-wiring more effectively blocks these distortion signals by placing the low resistance of the amplifier between the woofer, for instance, and the input terminals of the midrange. This is a relatively subtle effect, but may be of interest in a refined system.

Sincerely,

Bob

Note: After having bi-wired their speakers, some people immediately noticed a much cleaner midrange and wider apparent dynamic range, especially in music with extended high-level bass.
And one does not have to use heavy-gauge cable for the midrange/tweeter section of the speaker. For the bass, a heavier gauge is preferable, of course.
The longer your speaker cable runs, the more important bi-wiring becomes.

Please give scientific reference that speaker cables cause distortion. At worst a speaker cable adds resistance which can change the Q of the bass speaker alignment.

The series inductor/inductors of the low pass crossover will severely limit back EMF from a woofer. This is the only driver where this is only an issue. However in an amp with low source resistance and high slew rate, back EMF will help control the woofer overhang in an active biamped system. Passive crossovers pretty much negate this.

Bi wiring is nothing more than a long high resistance shunt bar. The onus is on you to show how this is not so. If you think about it, it is no different than having the jumpers have the same resistance as the added speaker cable.

Any other theories are just extrapolating beyond the facts.

[Loren42]

Forgive the basic question but I am really baffled.

My setup:
I have a pair of KEF iQ9 speakers(rated 20 to 150 Ohm) and an Onkyo SR-607(7channel x 90 watts). Both speakers and amp are capable of biamping...

My question/problem:
If I biamp my speakers I am supplying 90x2 watts to each speakers...could it burn my speakers if I turn up the volume, since I am sending more power than the could endure? The question I am asking is it almost already happened..After I hooked them, immediately noticed that one of the tweeters on a speaker has gone silent..it simply didn't produce any sound above 2000 Hz. I RMAd that one and tomorrow I am getting the replacement. I don't want to burn this one with bi-amping! So please help!!

Thanks,
Damon

AS others have pointed out, bi-amping will not over power your speakers.

As for the blown tweeter, do you have a capacitor in-line with the tweeter?

If not, you should put a 50 µf non-polarized cap in line of the tweeter. This acts as a DC block to protect the tweeter.

When you first turn on an amp you may get a pop, which could blow the tweeter. A passive crossover would normally block that, but an active system has no protection unless you put one in there.

Also, it is good practice to turn on the power amp last when turning everything on and make the power amp the first thing you turn off when you shut it down.

I think the bi-wiring argument is already well represented, so I won't jump into that mess. :D

[TLS Guy]

AS others have pointed out, bi-amping will not over power your speakers.

As for the blown tweeter, do you have a capacitor in-line with the tweeter?

If not, you should put a 50 µf non-polarized cap in line of the tweeter. This acts as a DC block to protect the tweeter.

When you first turn on an amp you may get a pop, which could blow the tweeter. A passive crossover would normally block that, but an active system has no protection unless you put one in there.

Also, it is good practice to turn on the power amp last when turning everything on and make the power amp the first thing you turn off when you shut it down.

I think the bi-wiring argument is already well represented, so I won't jump into that mess. :D

There already will be a cap or caps in series with the tweeter in the high pass filter of the crossover, so he won't need another one, like you would need the 50 mfd cap with an active crossover. In the latter case the amp would be directly connected to the speaker without the addition of a cap.

The more I think about this, the more I fell it is likely he clipped the amp as he thought he could play it louder. It is not generally realized that an amp clips easily when producing no or little power, as it is easy to exceed the demands of the voltage of the power supply. In fact into an eight ohm load, the clip point would be pretty much identical whether the amp was delivering power to a load or not.

[Loren42]

There already will be a cap or caps in series with the tweeter in the high pass filter of the crossover, so he won't need another one, like you would need the 50 mfd cap with an active crossover. In the latter case the amp would be directly connected to the speaker without the addition of a cap.

The more I think about this, the more I fell it is likely he clipped the amp as he thought he could play it louder. It is not generally realized that an amp clips easily when producing no or little power, as it is easy to exceed the demands of the voltage of the power supply. In fact into an eight ohm load, the clip point would be pretty much identical whether the amp was delivering power to a load or not.

Maybe I misunderstood the poster's question. I thought he had already bi-amped and lost a tweeter.

I would have assumed that he would have bypassed or removed the passive crossover when bi-amping. Maybe not? I do not know anything about the KEF speakers.

[TLS Guy]

Maybe I misunderstood the poster's question. I thought he had already bi-amped and lost a tweeter.

I would have assumed that he would have bypassed or removed the passive crossover when bi-amping. Maybe not? I do not know anything about the KEF speakers.

The OP was passive biamping. He took off the strap between the high and low pass filters. Both amps are reproducing the same full range signal, and the amps are connected to the passive low and high pass filters respectively. A really pointless exercise and with some degree of hazard.

[R-Carpenter]

Could it be that the crossover really has 2 outputs on the outside of the speaker and goes to the same terminal inside? I think it's known as a fake bi wire or bi amp. If so, there's a possibility of generating a strong DC pulse and blowing a tweeter. I'd start with puling out the crossover and posting pictures. It could also be a wire fallen off or burned.:confused:

[mtrycrafts]

Could it be that the crossover really has 2 outputs on the outside of the speaker and goes to the same terminal inside? I think it's known as a fake bi wire or bi amp. If so, there's a possibility of generating a strong DC pulse and blowing a tweeter. I'd start with puling out the crossover and posting pictures. It could also be a wire fallen off or burned.:confused:

I would think if that is the case, the company is committing fraud.:eek:

[R-Carpenter]

Not necessarily. If 2 of your amps, used for bi-amping have exactly the same output and magically matched output devises, then you would be amplifying 1 speaker with 2 amps. I don't know for sure and it's just an uneducated guess but I remember seeing crossovers with the external jumpers on terminals but joining inside to the same.:eek:
Pull out the crossovers, let's see.