In a 3-way speaker with two pairs of connectors, what will be the best arrangement for those bi-wire (or bi-amp) connectors:
a) [Tweeter] + [Midrange and Woofer connected together] (T - MW)
b) [Tweeter and Midrange connected together] + Woofer (TM - W)
XO freqs. about 3500Hz and 200Hz.
Thanks and regards
a) [Tweeter] + [Midrange and Woofer connected together] (T - MW)
b) [Tweeter and Midrange connected together] + Woofer (TM - W)
XO freqs. about 3500Hz and 200Hz.
Thanks and regards
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I don't think bi-wiring is going to matter.
Bi-amping, on the other hand, can make a huge difference, although I assume you're staying with the passive Xovers as you listed the frequencies already. In that case, I'd run the tweets and midrange off the same channels, leaving the other 2 channels for the woofers.
Bi-amping, on the other hand, can make a huge difference, although I assume you're staying with the passive Xovers as you listed the frequencies already. In that case, I'd run the tweets and midrange off the same channels, leaving the other 2 channels for the woofers.
Yes, I have passive Xovers and I intend to passive bi-amp but since it's a 3-way, my doubt is which driver should be isolated - the tweeter or the woofer.
One one hand the woofer takes more power than the other two together, thus, if using equal amplifiers it would make sense to go for a tm + w configuration.
On the other hand, if I go for a t + mw configuration, I can use a softer (and much weaker) amplifier on the tweeter alone, like one of those wonderful tube amps with very low power.
What do you think?
This isn't really a 3-way but a 2.5 one. The midrange (woofer in a sealed box) rolls naturally at 200Hz.
One one hand the woofer takes more power than the other two together, thus, if using equal amplifiers it would make sense to go for a tm + w configuration.
On the other hand, if I go for a t + mw configuration, I can use a softer (and much weaker) amplifier on the tweeter alone, like one of those wonderful tube amps with very low power.
What do you think?
This isn't really a 3-way but a 2.5 one. The midrange (woofer in a sealed box) rolls naturally at 200Hz.
if the 3way crossover has three inputs then consider tri-amping.
Alternatively bring the Extra crossover input to the outside for a third pair of terminals.
Bi-wire two pair of terminals and bi-amp the final pair.
Two amps driving three sets of wires.
Try various arrangements and listen for any differences.
I have found that bi-wiring gives a gain almost as much as adding the extra amplifier.
Alternatively bring the Extra crossover input to the outside for a third pair of terminals.
Bi-wire two pair of terminals and bi-amp the final pair.
Two amps driving three sets of wires.
Try various arrangements and listen for any differences.
I have found that bi-wiring gives a gain almost as much as adding the extra amplifier.
Andrew, I understand your point. There's nothing like trying out several combinations. I was just trying a shortcut, as I planed it to only have a pair of terminals.
Have you noticed that most loudspeakers in the market nowdays, including most highend models, with 3 and sometimes 4 ways, only have two pairs of ports?
In some cases previous models had more terminals but they reduced them to two pairs, even in much more expensive upgrades.
Why will that happen?
Have you noticed that most loudspeakers in the market nowdays, including most highend models, with 3 and sometimes 4 ways, only have two pairs of ports?
In some cases previous models had more terminals but they reduced them to two pairs, even in much more expensive upgrades.
Why will that happen?
Keep in mind the fact that you may (probably will, actually) need to use a signal level crossover before the tweeter amp if you do this, otherwise you'll still amplify the low frequencies with the weak amplifier and severely drive it into clipping.
PeteMck, given the midrange is also a woofer won't it present the same intermodulation distortion treath to the tweeter?
Stu, I believe the energy dissipated in the high-pass filter will be much less than the one that would be dissipated if the same amplifier was also connected to the other drivers (and filters).
Stu, I believe the energy dissipated in the high-pass filter will be much less than the one that would be dissipated if the same amplifier was also connected to the other drivers (and filters).
The advantage that comes from bi-amplifying is due to the higher impedance presented to the amplifier by the half crossover.
Amplifiers generally perform better when driving higher impedances but the effect can be quite subtle when they are operating well within their load specification.
If the amplifier is operating at near it's load impedance limit, then raising the load impedance will make a bigger difference to the final sound coming from the speaker.
Both amplifiers are working with a wideband signal and both must be run within their voltage and current limits. This is no different from running a single amplifier into both parts of the crossover. You set your maximum volume to avoid clipping whether you are bi-amplifying or normal amplifying.
Amplifiers generally perform better when driving higher impedances but the effect can be quite subtle when they are operating well within their load specification.
If the amplifier is operating at near it's load impedance limit, then raising the load impedance will make a bigger difference to the final sound coming from the speaker.
Both amplifiers are working with a wideband signal and both must be run within their voltage and current limits. This is no different from running a single amplifier into both parts of the crossover. You set your maximum volume to avoid clipping whether you are bi-amplifying or normal amplifying.
The energy dissipated will be less, but the amplifier will still be producing the low-frequency voltages - if you use a low-power amp, it won't have the voltage to produce the full signal and it will clip.
If you're considering bi-amping you might as well go all the way and cross over at the signal level.
I don't agree.
Changing from a single amplifier to bi or tri-amping is easy and equally easy to revert to the original arrangement.
Removing the passive crossover and replacing with active crossover stages to create an active speaker set up is an enormous project that will stretch many beyond their capabilities and requires a lot of test hardware and software and a lot of time.
Stu, I may be wrong, but I think this is not true.
I believe if the ampifier has no load it produces nothing (no current flowing); and if it has a high-pass and a load it only produces the frequency curve allowed by that filter. Of course that some power is dissipated at the filter (inductors and capcitors).
Furthemore the power dissipated grows as frequency decreases, so probably at 0-500Hz you will be spending more energy than at 500Hz-20KHz.
Andrew, that is the case - I've gone for passive xo for practical reasons. To make/buy an active crossover and correctly tune it is a very hard mission. Also you are forced to use as many amplifiers as the drivers and can never use a better single amplifier with the speakers (or pair of amplifiers, if it is a 3-way or above).
Fair enough, it can be quite involved moving to active crossovers. I just don't think "passive" bi-amping is really bi-amping at all and would probably offer no material benefit over using a single appropriately sized amplifier to begin with... but your experiences may vary.
If you're still considering it, though, I'd go with the TM-W combination with similarly rated amplifiers. You'll either be able to get a higher total power out or run the amps cooler and with less stress on the power supplies.
I'm happy for someone to point out an obvious mistake I'm making, but I still think you might be mistaken about the situation with the low-powered tweeter amplifier.
Amplifiers are ideally voltage sources, so if you feed the same signal into your amps, you'll get the same voltage out. When you connect a load, the current changes but the voltage should stay the same. If your amplifier can't produce the low frequency voltage, it will clip, regardless of whether you even have a load connected or not. Low power amplifiers generally have a lower supply voltage, so sending a full bandwidth signal to them will clip them before you are able to draw anywhere near their rated power (it's possible to design an amplifier to work this way, but I don't see a reason for anyone to design an amplifier to amplify signals that will never see a load).
If you're still considering it, though, I'd go with the TM-W combination with similarly rated amplifiers. You'll either be able to get a higher total power out or run the amps cooler and with less stress on the power supplies.
I'm happy for someone to point out an obvious mistake I'm making, but I still think you might be mistaken about the situation with the low-powered tweeter amplifier.
Amplifiers are ideally voltage sources, so if you feed the same signal into your amps, you'll get the same voltage out. When you connect a load, the current changes but the voltage should stay the same. If your amplifier can't produce the low frequency voltage, it will clip, regardless of whether you even have a load connected or not. Low power amplifiers generally have a lower supply voltage, so sending a full bandwidth signal to them will clip them before you are able to draw anywhere near their rated power (it's possible to design an amplifier to work this way, but I don't see a reason for anyone to design an amplifier to amplify signals that will never see a load).
I agree. The amps will run cooler because they will disspate less power. This contradicts your claim that it will be equally hard for the amp.
I think not.
No load = infinite impedance = no current = no anything (which includes no clip)
This is where our opinions do not match (one of them is wrong).
What we call a load is actually a impedance curve over the frequency (0-20KHz). The energy spent is the sum of energy spent on this curve.
When using a passive high pass filter the impedance curve 'seen' by the amp is transformed so that as the frequency decreases the impedance rises significantly, thus drawing much less power from the amp.
I think this is a common miscomprehension regarging passive amplification.
Of course that passive crossovers have their intrinsic power loss and introduce distortion and phase shifts, but in terms of power reserves there is not much difference from an active setup.
Actually, with a well designed passive xo in a passive biamp system, it will be hard to beat usng the same amplifiers in an active biamp system except if you use a digital xo and spend some time playing with it.
I think that Stu is right about pushing the smaller amp into clipping with bass signals when it only should deal with the treble. At least this will be the case with solid state BJT/MOSFET amplifiers.
If I connect a SS amplifier to the oscilloscope (ie, around 1Mohm loading) and apply a suitably large input signal, I will observe clipping of the output at the point where the output stage runs out of voltage swing capability. This is true despite there being no real power through the system. If I added a passively crossed over tweeter to this amplifier and applied a lower level high frequency signal alongside a "clipping level" low frequency signal, I am sure I will still observe clipping on the scope and hence experience degredation of the tweeters output, perhaps even damage from the clipping.
If I connect a SS amplifier to the oscilloscope (ie, around 1Mohm loading) and apply a suitably large input signal, I will observe clipping of the output at the point where the output stage runs out of voltage swing capability. This is true despite there being no real power through the system. If I added a passively crossed over tweeter to this amplifier and applied a lower level high frequency signal alongside a "clipping level" low frequency signal, I am sure I will still observe clipping on the scope and hence experience degredation of the tweeters output, perhaps even damage from the clipping.
the passive crossover is designed to be driven by a single amplifier and usually has the option to bi-wire (4terminals instead of 2) and bi-amplify.
If one chooses to bi-amplify, both halves of the crossover over must be driven with the same voltage signal. i.e. as if they were driven by a common amplifier.
The delivered power does not affect the requirement that the same voltage must be applied to both sets of terminals.
One can choose to precondition (EQ) the signal going into the single amplifier, eg. band filter or add tone controls, but the resulting sound coming out will not replicate what was originally fed into the system.
Similarly one can precondition the signals going into the pair of bi-amplifiers, but this too will alter the sound coming out of the speakers. If the EQ is applied well away from the pass-band of the crossover/driver then the alteration to the sound may be inaudible, i.e. a tweeter amplifier and driver with a passband from 3kHz to 30kHz will probably sound unaltered if the EQ is applied outside the band width of 300Hz to 300kHz.
If one applies EQ to a tweeter amplifier that feeds a 3kHz crossover and driver that is close to that passband, eg. a high pass 1kHz filter before the tweeter amplifier, the resulting sound will almost certainly be different and likely of inferior quality.
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That's a claim I didn't make, though. There will be a difference, but:
a) You're generally better off using one strong amplifier rather than two weaker ones.
b) Even if some parts of the system are less stressed, the amplifier will still clip. The amplifier will still clip with NOTHING connected - if you have test equipment you should see this quite easily.
I think not.
No load = infinite impedance = no current = no anything (which includes no clip)
No anything? You didn't mention the voltage, the crucial element. By definition, the voltage will be exactly the same for both amplifiers, and the voltage rails powering the amplifier are an effective brick wall for the signal. If you're trying to amplify a signal beyond that brick wall, the signal out won't be the same as the signal coming in. It will be highly distorted and may even destroy your tweeter.
Oh, I agree. Which is why I think if you're considering a separate low-power amp for the tweeter you really have no option but to remove the passive crossover and replicate it actively which may not be easy.
There may be merit to bi-amplification with passive crossovers in some situations, but if you don't know what you're doing, you're likely to make things much worse.
absolutely not.
Wiring a second identical amplifier to drive the second pair of terminals cannot, in my opinion, makes performance worse.
Passive Bi-amplification is probably the easiest to NOT get wrong compared to all the other modifications that can be made to speakers and amplifiers.
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