Help with speakers Martin Logan SL3

Martin Logan speakers are very demanding. I have a pair of Monoliths and love them. The basic problem is the panels reduce the impedance loading to 2 ohms and below during some passages of music. Then the woofer asks for a big voltage for that kick drum to come in. The combination is almost unbearable for any modest powered amp. An amp that is stable at very low impedances (Krell, Levinson, some of the Classe) can keep it from clipping, but you still have huge demands on the amp. Bi-amping completely solves this issue, but of course that can be pretty expensive. Hope that helps.

Absract7 was correct I have a pair of QuestZs & they were tortuing an Adcom 125wpc amp. I went to A Krell KAV250a & I got much better sound & they handle the Logans with ease. Since you already have a Classe preamp why not try one of their amps to go with it?

Well the amplifier I am using is one of the most powerful, if not the most, multi channel amplifiers out there, rated at 500x5@8, and higher into 4/2.

It delivers 50W into "A". Is it possible the amp clips because the speakers can not handle the amount of power being sent its way?

Dan

Hello Dan:

Great speaker needs a great amp. You are fooling yourself with your current CAL Home Theater amp. I have HT using ReQuest mains, SL3 rears and Logos center. I use a Levinson ML3 on the ReQuests, a Perreaux PMF3150 on the SL3's and a B&K ST1400 Monoblock on the logos. Find an older "big iron" Classe or Levinson to power your main SL3's. You'll be much happier!

Paul

Dan: Even though your amp has 500 watts it still has only 100 perchannel. M.L. are noted for their difficult impedance loads they present to an amplifier. a truly powerful amp will double down or come close to it. An amp that is capable of this will for example be rated 200 watts 8 ohms & 400 watts at 4 ohms. Look at your amps owners manual & see what it puts out for 4 & 2 ohms. A good HIfi shop will probably let you borrow an amp for a day or two which is what I did & even though I was lighter in the wallet there was no hesitation on my part once I had heard the difference.

Once again, I am confused. Per the manual, "The CL-2500 Multi-Channel Amplifier (MCA) provides 500 watts RMS to each of five
channels making this unit the most powerful home theater amplifier on the market today."

If I am getting (knowing price does NOT indicate quality) 500 watts per channel from a $7,500 amp, is it truely possible it is NOT ENOUGH?

Dan

I am using a SL-3 for the front Logos for Center and Scripts for rear. Have driven them with the following amps:
1) B&K 7250
2) Aragon 8008BB and 8008x3
3) Proceed HPA 2&3
4) EAD PowerMaster 2000
It never clip for any of these amps. It could be a bad amp if I am not wrong. Since Martin Logan are hard to drive. Wish you the best of luck in resolving your problem. If you need more advice feel free to email me.

Bill

Dan, didn't know much about this amp but I did some searching on the net for reviews. From everything I read that amp should have plenty of power to drive your Logans. You might want to check with Cal. Audio to see what they think. How loud are you trying to play these? Does the amp actually go into "protection" mode and shut down?

Thanks No_money and hifinerd,

As for loud, lets say reference levels. I can give a better description of what happens. First off, I get very little bass out of these, not uncommon. Using a Velodyne 18 for Home Theater, I am not concerned, however, in 2 channel, all low frequencies leave the room. So as I turn the Classe SSP-50 up to about -35 to -40 (-60 is the max) with each channel set at about +6dB (problem? should it be 0?) the two front channel, using balanced cables, clip. This means, the speaker continue playing, the amp still works, but the two dummy (good for people like me) lights come on sporatically reading CLIP. When I look at the bass driver it is COMPLETELY maxed, moving as if there is TOO MUCH power.

Keep in mind, the volume is VERY loud at this point! I just find it odd that the other speakers do not clip. I believe I have them all set at LARGE?!

Ideas?

hi, it sounds to me that your simply over driving the sl3, if you have balanced on your front and single ended on center and rears , you have 6db more output of gain versus the single ende d. plus if you added 6 db of gain on the front thats a total of 12 db or 4 times the power versus the other speakers. power doubles for every 3 db loudness example sl3 4 ohm load requires 2watts for90db 4watts 93db 8 is 96 ,16 is 99 ,32 is102, 64 is105db plus you need in reserve a ten times amount of power not to clip the signal on dynamic peaks. example 8average watts 80 on peaks. on your loud music 32avg 320 peak 64avg 640peak, you can see how quickly you can use all that power for a small increase in volume. hope this helps you understand power versus loudness.

You should get decent bass response from your SL3'S. Not earth shattering but it should be decent. Are you sure you system is not inverting phase?