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Multi-Way Conventional loudspeakers with crossovers

Biwire/Biamp T-MW or TM-W
Biwire/Biamp T-MW or TM-W
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Old 1st September 2009, 07:06 PM   #1
Sony is offline Sony  Europe
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Default Biwire/Biamp T-MW or TM-W

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

Last edited by Sony; 1st September 2009 at 07:08 PM.
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Old 1st September 2009, 07:38 PM   #2
Glowbug is offline Glowbug  United States
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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.
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Old 2nd September 2009, 10:22 AM   #3
Sony is offline Sony  Europe
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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.
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Old 2nd September 2009, 10:55 AM   #4
AndrewT is offline AndrewT  Scotland
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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.
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Old 2nd September 2009, 11:07 AM   #5
Sony is offline Sony  Europe
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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?
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Old 3rd September 2009, 08:49 AM   #6
PeteMcK is offline PeteMcK
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b) [Tweeter and Midrange connected together] + Woofer (TM - W) is the better arrangement, stops intermodulation distortion from the woofer
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Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
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Old 3rd September 2009, 08:53 AM   #7
Stu is offline Stu  Australia
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Quote:
Originally Posted by Sony View Post
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?
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.
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Old 3rd September 2009, 11:21 AM   #8
Sony is offline Sony  Europe
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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).
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Old 3rd September 2009, 12:26 PM   #9
AndrewT is offline AndrewT  Scotland
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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.
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Old 3rd September 2009, 12:57 PM   #10
Stu is offline Stu  Australia
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Quote:
Originally Posted by Sony View Post
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 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.
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