Bi-amping?

[FatJ]

Somebody set me straight on this one please. I thought that in order to bi-amp these babies all I had to do was split the output from the preamp and go in to 2 different amps (or 2 different channels of a multichannel amp), remove the jumpers, and run wire from each amp to the top and bottom posts.

Now I've been reading through many of these posts and hear a lot of talk about the crossover. It also sounds like not all Logans are created equal here. I've got a customer that wants to bi-amp his Prodigies and his Ascents in his theater room. Does he need to do something special or can I just sell him more amps and wires and hook it up?

Thanks to all

 

[Rich]

Somebody set me straight on this one please. I thought that in order to bi-amp these babies all I had to do was split the output from the preamp and go in to 2 different amps (or 2 different channels of a multichannel amp), remove the jumpers, and run wire from each amp to the top and bottom posts.

Now I've been reading through many of these posts and hear a lot of talk about the crossover. It also sounds like not all Logans are created equal here. I've got a customer that wants to bi-amp his Prodigies and his Ascents in his theater room. Does he need to do something special or can I just sell him more amps and wires and hook it up?

Thanks to all

You are correct. In regards to the Prodigies and Ascents all you have to do is split the preamp signal and send one feed to one amp connected to the inputs for the panels, and send the other feed to another amp connected to the inputs for the woofers (and remove the jumpers, of course). The internal crossover will do the rest. One caveat: the amps need to be matched as to gain, or you will need an inline attenuator on the amp with the highest gain. As you mentioned, you can also use separate channels of a multichannel amp to biamp.

Lots of folks prefer to put a tube amp on the panels and a solid state amp on the woofer, but you could put a tube amp on both or a solid state amp on both. You will get improved sound, no matter which way you choose to biamp in my opinion.

Many folks prefer to use external crossovers for a myriad of reasons. I am no expert on that, so I will let others with more knowledge chime in here. Basically, I think you can get a higher quality crossover than the stock ML crossover and you can have more control over the timing, slope, phase, etc.

One more thing. As far as power goes, I would not recommend using less than 200 wpc from a quality solid state amp on the woofers of the Ascents and preferably 400 wpc or even more on the woofers of the Prodigies in order to keep transient response quick and distortion low. Obviously, the quality of the amp is a lot more important than the actual wpc numbers. But a more powerful amp in general is going to give better bass with lower distortion on these woofers. Just my opinion.

 

[TrumpetDoug]

Another great thread

Rich,

Thanks for the reply to this ? by Fatj. I am looking to do the exact same thing with my Ascents. I have a Threshold 300 S II and a smaller Mc. that I cannot remember the number of.( I believe it is 75 wpc.) I can adjust the output of the Mc. but obviously not the output of the Threshold. I was wondering about the external x-over thang, nice to know I probably won't need it.

Doug - out

 

[Cherian]

If I'm not mistaken to use a different crossover one has to first disconnect or disable the internal crossover inside the speaker. I know this is not the case with the Monolith speakers because the crossover is already external.

 

[BrianB]

Bi-amping 101

I'm about to try this with my Ascents as well utilizing a Threshold S/500II driving the woofers and a Threshold 400A driving the panels.

But there are 2 methods to bi-amping.

Passive bi-amping is what we're talking about in this thread. That is, utilizing the crossovers in the speakers themselves. This is somewhat inefficient because (in my case, anyway), I'm using a line stage preamp that doesn't have any crossover component. i'll be sending a full frequency signal to both amplifiers, the amps will amplifiy all frequencies and send them to the speakers, even though the Ascent crossovers will bleed those high freq. from reaching the panels and the low signals from reaching the woofers.

Active bi-amping is much more complicated where the internal speaker crossovers are bypassed an external crossover is required (or in some cases, some HT type receivers will have crossovers built in) but these are typically electronic and not the same sonic quality as the discrete ($$) external crossovers. Crossover frequencies, both high pass and low pass need to be set as well as crossover slopes which is not a simple task. But in this case, the amps receive only what will be reproduced for those specific drivers and don't waste power on those frequencies that are bled off by passive systems.