Amp matching in Bi-amping - ideas check

[GaryProtein]

Originally Posted by substance

Ok garry, you win.

I wasn't looking to win.

I was looking to help you set up your system.

[John49]

Originally Posted by substance

Is this question related to my substance addiction?

It is related to your forum name and that I thought you were being given a hard time. British humour...

[substance]

Originally Posted by John49

It is related to your forum name and that I thought you were being given a hard time. British humour...

I understood it the first time, I was going along with your humor thank you.

I am sure it wasn't Gary's intention to give me hard time. I am totally cool with him. I would like to think he is cool with me as well.

It appears being a new member with few posts, I will need a little time proving myself that I know a thing or two about this hobby. Sorry for my inconvenience, lets talk amps now please

[Mctwins]

Originally Posted by GaryProtein

Thank you for this youtube video.

It should be required viewing for all!

You are welcome..

[Mctwins]

Substance......

There must be a reason why the Martin Logan CLX only have one pair of binding post, meaning, that it is not intended for Bi-amping these speakers.

Let's say you are bi-amping your speakers perfectly you will end up to almost the same result as it has been tuned by Martin Logan engineering depertment. Again, I don't see the point.

To me, you have the wrong speakers to mess with bi-amping.

[substance]

Ok I didn't really want to do this but my word isn't enough so let's hear from the man himself

Nelson Pass (link below, post 20)
"
Actually though, I find that degree of adjustability most
useful for subwoofers, being that they usually need some
equalization also.

I occasionally put 1 or 2 poles down at 22 Hz or so to really
flatten out the response and then additional poles to get
rid of the woofer above its usable frequency. It may only
result in two octaves of response, but it's flat.
"
Pass Labs XVR1 crossover - Page 2 - diyAudio

If you read the example projects (try example 2) in the owner manual, he uses poles at different points to compensate for peaks in the mid drivers. There are more examples if you search. It is not room eq for sure, I used the words kinda, semi for that reason but it is good enough for me.


On the bi-amping: these are direct quotes from Peter Sodenberg(Martin Logan), we exchanged a good number of emails, these are what I just copy pasted from a couple of them.

Now makes some sense. I would use the 50hz low pass to the subs. You might want to go to 12 db as an experiment. As to the high pass, 60 hz is good. You will probably want to experiment with the 6 or the 12 db slopes. You do want a slight gap like the 50/60 we are talking about. The two products will couple at the xover region so if you did 60/60 you actually may get a peak at the frequency.
"
As to the CLX, the high pass internally is at 360 for the bass to the mid/tweeter panel. We traditionally use 12db as the best compromise for roll off/on as going much steeper would makd the speaker harder to drive due to xover complexity and less steep won’t relieve enough stress from associated panels as well as some comb filtering issues as the two drivers may interfere.

As to bypassing internal xovers, careful. You have to use two amps of exactly the same gain or you will be fighting levels between them. of course your xover will have that. going active will have some nice benefits, just proceed with caution about modifying a speaker.

Easy to try it. Bryston will be clean so the removal of some low bass load off of the CLX may make it sound cleaner rather than make it run full range. We don’t have a high pass on the CLX as it will run as low as it can on the signal it receives. "


Yes modifying a speaker is not for everyone. It doesn't mean it can not be done or shouldn't be. Even speakers with bi-amp connections have built in xovers enabled no matter. You would have to go beyond the original design and remove the xovers for active bi amping.

[Mctwins]

Tell the tale when you have bi-amped your speakers.

[jrsystems]

I think your modification would be a significant hit on the resale value of your speakers, just a consideration.

How do you like the current integration of the CLXes and the JL subs with the Pass xover? I had CLXes with a single f113 and no external and it was never quite right. I've been experimenting with my current Raidho D1s and the f113 using the crossover in my Oppo 105 with some terrific results. I would like to get a proper analog electronic crossover such as a CR1 at some point. I can't swing a CR1 right now, but I am considering getting a Marchand 80hz high pass filter and use the subs low pass filter to hold me for a while.

I love the sub sat sound. I was kind of bummed that I never got it right with the CLXes. I was experimenting today listening to the D1 full range through my C2200 and then using the Oppo as preamp and crossover with the sub. The sound was warmer and a better stage with the C2200 but the bass was obviously better and it just sounded great with the sub through the the Oppo. I want the dedicated crossover to get the best of both.

[substance]

I actually use a pair of Martin Logan descent i subs now and they are more suitable. JLs had more output but the CLXes aren't very efficient, they don't play that loud.

Xover is worth it only if you are going to spend a lot of time on it. You need a good microphone, a pc with mic in, and some software. Typically you want to integrate with a 6db slope but this might be too much stress on the satellite speakers. I have 12db slope high pass at 22Hz on the subs and 6db slope low pass at 66Hz on CLXes. JL subs have a high pass/notch filter at 20Hz, the low xover point I used didn't work well.

The built in xover on the descent i has a point specifically arranged for CLXes. I believe its between 25-35Hz at 12db. CLXes themself have a response of 56Hz at -3db. I made this slope a little steeper with the active xover to take away a little more stress from the towers.


The xover on the Oppo is digital. It's even better than an active xover but the volume control is also digital which isn't good. Digital volume decreases bit depth to lower the energy/volume. If you are listening 16bit CDs, at half volume, you are listening to a couple of bits less.

[Citation]

Hello Substance, were you able to bi-amp & externally crossover your CLXs? I am anxious to do the same with mine (but need some coaching).