bi-amp / bi-wiring speakers

I've got two PM300's driven by a C1 pre-amp. The LSI9's are rated at 120 watts, and the amps are either 120 or 150 watts into 4 ohms, can't remember.

Just an afterthought; if you're considering bi-amp/bi-wiring, take into account that the total speaker resistance/impedance may be 8 ohms (for example), but the woofer & tweeter may be different individually. It's something to consider...

I am pleased to say that my recent switchroo from horizontal to vertical biamping yielded significant improvement using two TFM-35x amps - for some reason it not only gets louder, it sounds better - more natural??? Hell, maybe louder is simply more natural!

Likely the obvious advantage to spreading bass note demands across two separate amplifiers.

What crossover did you use?

I know this is an old thread but I figured this is where I'd start... OK, whats the advantage of bi-wiring? I've been doing it for years because my Paradigm manuals say to do so, but I honestly don't really know why?

I know this is an old thread but I figured this is where I'd start... OK, whats the advantage of bi-wiring? I've been doing it for years because my Paradigm manuals say to do so, but I honestly don't really know why?

It divides the amp power. You have one channel driving only the upper or lower range instead of the full speaker. Provides more power in total for the speaker.

?...MMmm, I'm only using 1 amp. (TFM 35) 2 wires from each output, 1 up top, 1 to the low end, each side..?

I know this is an old thread but I figured this is where I'd start... OK, whats the advantage of bi-wiring? I've been doing it for years because my Paradigm manuals say to do so, but I honestly don't really know why?

Bi-wiring
Here's a diagram of a typical biwiring speaker. The red line is the external jumper (for using only one cable to the speaker).

By removing the jumper and running two cables (one for lows and one for mid/highs), the speaker is now bi-wired (or passive biamped).

Imagine an amplifier producing 100V at 100Hz and 25V at 1KHz. (arbitrary numbers). Each channel of the amplifier is doing the same amoiunt of voltage swinging between rails (this mixed signal will look kind of like a bumpy sine wave) as in the bottom signal (red trace is there for reference).

As Frequency increases the woofer channel's inductor (L1) resistance increases (if the jumper were there this would 'steer' the signal to the mid/tweet) until eventually the woofer is doing nothing (not drawing a load from that channel) although the channel is still producing the voltage.

In the upper channel, as frequency decreases this channels capacitor (C1) resistance increases (if the jumper were there it would 'steer' the voltage to the woofer) until the mid/tweet is seeing no signal, although the channel is still producing a voltage.

Benefits:
reduced cable impedence by half
reduced loading of output stage of amp
[your theory here]

Uglies:
each channel is still responding to a full spectrum signal
Passive crossover components still consuming power
[your theory here]

Biamping

All the passive crossover compenents are removed and each amp channel is tied directly to the woofer or tweeter. An active crossover splits the signal before it reaches the amplifier; each channel is only responding to the voltage it's going to load the driver with. You can see in the diagram (the red 100 hz signal is there for reference) that with an active crossover (the red trace), the amp's pre-driver stage isn't swinging as high to the voltage rails (the black trace)...there's more headroom, and the voltage isn't going to be used by the output stage anyway.

Benefits:
increased amplifier headroom
tighter dynamics
no 'wasted voltage' in amplifier driver stage
no passive crossover components consuming power
better woofer damping
[your theory here]

Uglies:
higher cost
modification of speakers
[your theory here]

Correct me if I'm wrong, but isn't the whole idea of bi-amping to clear up each (bottom/top) section of the audio spectrum by only running those particular frequencies thru the amp? You are wasting bass energy in the treble amp if you run full spectrum sound and vice versa.....????

Maybe I'm missing something here, but how do you run particular frequencies thru an amp?

With an Active Crossover.

This guy explains the bi-amping thing better than me (and he draws better too)

http://sound.westhost.com/bi-amp.htm#basics

"To illustrate this point, Figure 2 shows two signals, each of 1 Unit peak amplitude. As can be seen, when the two are combined, the amplitude is much greater. The maximum peak amplitude is now 2 Units - double the peak voltage and four times the peak power of each signal individually. Power increases as the square of voltage, so twice the (peak) voltage is four times the power."

So bi-amping reduces power requirement by 4 (or increases the headroom of your amp fourfold, whichever way you want to see it)

-quote;
-Yes. Any speaker that has a dual set of binding posts will work the same, not just Polk speakers.






-***indeed, i have an original mr Carver 'original' schematics, [for bi-wiring the silvers]
-***imagine plats are'nt to different

-***shows, adding an extra pr of binding posts and at what points

I know this is an old thread but I figured this is where I'd start... OK, whats the advantage of bi-wiring? I've been doing it for years because my Paradigm manuals say to do so, but I honestly don't really know why?

With many speakers and amps, the ONLY advantage to bi-wiring is that is causes you to put more money in the pockets of the wire companies...

It has been my experience (and the experience of several of my ML-owner friends) that if you're not going to bi-amp, then you're going to get better sound from shotgun wiring to the woofer posts and then using REALLY GOOD jumpers to the "highs" post. In about 80% of the applications (speaker/amp combinations) this will most likely give you better sound than bi-wirng, at a GREATLY reduced cost (saved money on wire=more money toward music!)

But depending on your amps and your speakers, and what kind of wires you are using, YMMV...

--Richard

The only thing that makes sense to me is (theory) the crossover works more efficiently with bi-wiring than with just one cable. Rich's diagram shows this. Thanks!

Just so you have the extra information, I use separate passive cross over networks--one for thehigh frequencies with my Sunfire's channel tap optimized for "Current and the second Sunfire channel optimized for voltage. One two channel amp for each speaker. Now it's true that if I used an active xcrossover to process the signal I would get more power---but I also would have to buy more interconnects and lose the advantage of having a state of the art pre-amp driving all the amps. I have this old Audio Research tube pre-amp which cost me $4000 for just a line stage back when they first started making pre-amps without phono sections that adds so much to thje detail. tonal balance, folcus and sound stage that I just can't give it up by running the signal through some $300 cross-over designed for use by musicians with live bands--not audiophile music.

I have respect respect for those who have opted for the other approach. If you had a really tricked out active cross over --that route would be a no brainer.

But driving Carver original Amazing speakers puts me in the position of having 2400 watts per channel in this passive bi-amp configuration since they are in essence a 2 ohm load speaker. I figure that's plenty of power even with the wasted bass in the passive x-ver network. And this way I get to preserve Bob's original equalization processes, etc in the passive network. I used to listen to the speakers with just one channel of each amp dedicated to one speaker. But by vertically biamping with the two amps--the sound I am now getting is absolutely blowing everyone away. Even my wife likes it! And I have a friend who is now selling his Quad ESLs with a highly modded Celestion subwoofers which were fabulous. But he likes what I've got right now infintely better.

Just an "inexpensive" idea/option.

I plan to buy one of these puppies to try out with my AL-V's and then give the Clearview back to my father, and give Tom his EQ back...
This thing is (3-way) and 2-way-able. with 30 band Eq... For $150... I'm going to try it.

The thing is built like a TANK too !!!!

http://www.sonicelectronix.com/item_583 ... 0EQX.html#



30 Band Parametric Equalizer with 3-Way Crossover
Brushed Aluminum Finish
Flush Mount Panel
Removable Aluminum Handles
PWM Switching Power Supply
Power and Clip LED Indicator
+-12dB EQ Boost / Cut
Subwoofer Control:
Variable Input Gain Control
Variable Crossover Frequency: 45 - 500 Hz
Mode Switch (Subwoofer / Full)
0 - 12 dB Variable Bass Boost
25 - 250 Hz Variable Bass Frequency
0° - 180° Phase Control
Mid-Range Controls:
Variable Input Gain Control
Mode Switch (LPF / Full)
45 Hz - 1.6 kHz Variable Crossover Frequency
Variable Equalizer Frequency Range: 25Hz, 32Hz, 45Hz, 63Hz, 80Hz, 100Hz, 125Hz, 180Hz, 200Hz, 250Hz, 325Hz, 400Hz, 500Hz, 650Hz, 800Hz, 1kHz, 1.3kHz, 1.6kHz, 2kHz, 2.5kHz, 3.2kHz, 4kHz, 5kHz, 6.4kHz, 8kHz, 10kHz, 12kHz, 14kHz, 16kHz, 18kHz
Tweeter Controls:
Variable Input Gain Control
Mode Switch (HPF / Full)
Frequency Multiplier Switch (x1, x10)
50 Hz - 5 kHz Variable Crossover Frequency
Variable Equalizer Frequency Range: 25Hz, 32Hz, 45Hz, 63Hz, 80Hz, 100Hz, 125Hz, 180Hz, 200Hz, 250Hz, 325Hz, 400Hz, 500Hz, 650Hz, 800Hz, 1kHz, 1.3kHz, 1.6kHz, 2kHz, 2.5kHz, 3.2kHz, 4kHz, 5kHz, 6.4kHz, 8kHz, 10kHz, 12kHz, 14kHz, 16kHz, 18kHz
Signal to Noise Ratio: 85 dB
THD: 0.05%
Input Impedance: 20k Ohm
Output Impedance: 150 Ohms
Dimensions: 19-3/4" L x 8-3/4" W x 2" H
2-year Manufacturer's warranty