Bi-amp by MC2505 and MC2205 with C2200

[SaturationPt]

The 2505 and 2105 manuals caution against running them without speakers connected, I believe that oscillation is the concern (not completely remembering). If my memory is correct there is a dummy load connected to the speaker on/off switch.

I don't know how the crossover high-pass and low-pass will affect this, have to blow the cobwebs from my brain to walk through the scenario but I think that it is okay.

Regardless, I agree with your suggestion to put the crossover before the amplifiers.

 

[Stereofro]

My solution may be a little more cost, but it will guarantee success.
Get an MEN220. Set theMC2205 for lower registers, and the MC2505 for upper registers.
Call the speaker manufacturer for what the proper crossover should be and what slope for the crossover.
Then, go through the setup procedure with the MEN220 calibrated mic.
I do not think you will be disappointed.
I have two MEN220's (one at home and one at office). For a while at the office, I ran two MC2500's (500 WPC, 1,000 Watts mono) for lower register, and twoMC2255's (250WPC, 500 Watts mono) for the upper register driving a pair of Legacy Signature III's (three 10 inch woofers each channel), and the sound was wonderful!
The surprise was not the increased bass I expected, but "cleaning up" the upper midrange (possibly due to eliminating "booming" from the mid-bass???).
My home speakers are not wired for bi-amping, so the MEN 220 just has to make do with balancing out the "single input" speakers. It still is nothing less than amazing in what it does.
The MEN220 will automatically adjust for different output sensitivities between channels and between different amps driving upper and lower registers. Looking at my signature, one can see I have a fair amount of MC equipment - but the MEN220 is ABSOLUTELY the best investment I have made in improving the system.

Hi, do you know if the MEN220 can possibly even out the gain of the separate amplifiers? I have a 275VI on the highs and 2 mono PSAudio m700's on the lows. They have about a 4db gain difference. Thanks in advance, Mike

 

[jdcarlson]

Hi, do you know if the MEN220 can possibly even out the gain of the separate amplifiers? I have a 275VI on the highs and 2 mono PSAudio m700's on the lows. They have about a 4db gain difference. Thanks in advance, Mike

The Men220 balances what comes out of the speaker. Thus, it should automatically take into account the difference in sensitivity (and/or output power) by adjusting the signal it feeds to the power amp to get the proper volume levels from each channel at the different frequencies.
Right now I am running KLH Model Nines (40 year old electrostatics) for treble registers with a MC2505 (50 WPC) and crossing over to two Velodynes for the bass registers run with two MC2255s in mono (500 WPC) - one for each channel and the MEN220 keeps them balanced.
So, if it can handle what I am throwing at it, I would not think it should have a problem balancing the power amps you have.

 

[kevzep]

The Men220 balances what comes out of the speaker. Thus, it should automatically take into account the difference in sensitivity (and/or output power) by adjusting the signal it feeds to the power amp to get the proper volume levels from each channel at the different frequencies.
Right now I am running KLH Model Nines (40 year old electrostatics) for treble registers with a MC2505 (50 WPC) and crossing over to two Velodynes for the bass registers run with two MC2255s in mono (500 WPC) - one for each channel and the MEN220 keeps them balanced.
So, if it can handle what I am throwing at it, I would not think it should have a problem balancing the power amps you have.

The MEN220 does not automatically adjust the outputs of the crossover, you need to do that manually.
MENU>OUTPUT SETTINGS>CROSSOVER OPTIONS>OUTPUT LEVELS.

Not sure why you think it does it automatically?

 

[jdcarlson]

You apparently missed my first post where I specified to call the speaker manufacturer and ask them for the correct crossover frequency and the slope to use.
Once the MEN220 has that information, it will then know how to interpret the input from the calibrated microphone with what it expects from the test signals is generates, then it will adjust the output (taking into account the crossover information entered manually) to the power amp(s) so that the sound coming from the calibrated microphone is properly balanced automatically adjusting for room resonances (thus the name "Room Perfect").

 

[twiiii]

To get the optimum signal to noise You should set the switch on the 2505 to the 2.5 volt position and turn the volume controls wide open. For the 2505 set the volume controls at the 12: OO o'clock position and that will give you the 2.5 volt sensitivity. But as the 2205 Has 8 db more out put capability. You are going to have to either use very educated ears or a spectrum analyzer and pink noise to get the correct balance.

Unless you have removed the passive crossover section for the woofers and the lower section of the mid range and are using an electronic cross over you really haven't gained anything. You'd be better off just. using the 2205, it has better highs, lower distortion and Power guard which will protect your drivers. The maim advantage to bi-amping is to lower IM distortion, increase speaker efficiency and match the different gain structures of the woofers versus the mid/tweeter. But as all your drivers are cone type, there is really no power benefits with bi-amping. If your HF drivers were horns, then their might be some advantages. JBL is very particular about the voicing of their speakers and have very well thought out recommendations when it comes to bi-amping their monitors speakers. Time to. do some research. You may find out they really don't recommend.

According to the JBL spec sheet there is a 2 db sensitivity difference between the more efficient mid and the tweeter. The mid is also more efficient than the woofer, so JBL has padded down the tweeter and the mid to match the woofer. So as I said unless you are using the electronic crossover and removing the passive parts there is no advantage to bi amping. And remember the speakers is only rated at 100 watts. So the 2505 with the slightest clipping could destroy your mid/tweeters. The 2205 is a little strong for the speakers but as long as you never flash the power guard lights their should be enough margin in the woofer to handle very short peaks approaching 200 watts. If you plan on driving the speakers full boar you would be better off with a MC 2125!.or a 7100..

 

[62caddy]

When biamping, using amplifiers of differing maximum output power effectively limits the system to that of the lower powered amplifier.

To derive the full benefit of the maximum power from the equipment in your possession, you need to the larger amplifier alone.

 

[kevzep]

You apparently missed my first post where I specified to call the speaker manufacturer and ask them for the correct crossover frequency and the slope to use.
Once the MEN220 has that information, it will then know how to interpret the input from the calibrated microphone with what it expects from the test signals is generates, then it will adjust the output (taking into account the crossover information entered manually) to the power amp(s) so that the sound coming from the calibrated microphone is properly balanced automatically adjusting for room resonances (thus the name "Room Perfect").

Room Perfect has nothing to do with the crossover or the crossover output levels. Room perfect is an auto EQ application.
The OP was asking if the outputs of the MEN220 were adjustable, and they are.
You can adjust the output levels to balance the HI and LO outputs to you liking, the outputs are adjustable to give you flexibility to use whatever amplifier with whatever input sensitivity you wish to use on your amplifier, and then also depending on the enclosure and the speaker sensitivity you might also want to adjust the levels as well.
To properly set it up, you need to use an FFT spectrum analyser and look at frequency response vs phase shift. This is how I set mine up. But the MEN crossover filters are pretty basic and there are no Linear Phase filters which is a bit disappointing, but the Linkwitz Reily 24 db/oct filters work OK.