I have question about frequency response and power issues


My current system is a Son of Ampzilla 2 and Mirage M1 speakers. I am using a Yaqin tube CD player and a Lexicon MC8 in bypass mode for a preamp. My question is basically this. My M1s have frequency response from 20 hz to 20K Hz. My amp has the same specs as does my CD player. My low end is phenomenal , I really am happy with it. I think I may be pushing my amp too hard as the M1s are rated at 250 watts but the amp is only 220. I am thinking about a Macintosh MC302 which is 300 watts output which I think will be perfect for my speakers. I am considering some B&W speakers but the frequency response ratings seem to all put the low end at around 35 Hz. Also the power requirements for the B&Ws seem to be very minimal. I don’t want to lose ANY of the belly buzz characteristics , so am I looking in the wrong direction as far as speakers go? Thanks in advance!


128x128jamesfokes
The M1's have amazing bass.  They love power and are fairly inefficient.  If I'm correct, they are 83db at 1 watt and run 6 ohms and they drop to 4 ohms.  Why don't you try bi-amping these?

Also, keep in mind that a speaker's wattage rating doesn't mean what you think.  Rating them at 220 watts is a suggested power rating for your amp.  But, 1 watt of distortion could blow them much more easily than 400 clean watts of music.  Overdriving your GAS could kill them.
I did have two Bryston 4B amps, bi-amping, but I got a little too happy with the volume and fried my tweeters. I had to send them to a guy in Canada that bought all the old Mirage M1 stuff. He rebuilt them and replaced the ferro-fluid. They are basically brand new, he did a great job. The preamp thing is interesting. Are you saying that my Lexicon is not powered? The way I understood it the Lexicon in bypass mode was a very good preamp. I did have a Bryston BP1 preamp that sounded very good but the Lexicon seems to have better imaging. The Bryston bit the dust, that is why I bought the Lexicon.

James I looked at the MC-8 manual and if I am reading it correctly using bypass mode the default setting is 0db. You can increase that up to +12db have you tried that? Or are you still set at the default 0db gain?
Hi James,

So, as loud as you wish to play the speakers, the amplifier overheats? 

I've looked at the Stereophile review, which is sadly incomplete compared to modern Stereophile measurements, and the Ampzilla specs. I think it's around 220W/8 Ohms and 350W/4. Now, 350 Watts is a lot of power, but it is possible James over-sold it. You don't need more power. You just need a stiffer amplifier with better cooling. 

Also, of course, make sure the amp has plenty of space above and around it. 

Another suggestion is to use them with a sub and high pass filter. That will reduce the load on  your Ampzilla and give you more head room. That doesn't guarantee you won't fry your tweeters again though. :) 

Best,

E

James, you’re putting waaay to much stock in the numbers you cite, particularly the M1’s frequency response of 20Hz to 20kHz. In the bad old days (pre high-end), mass-market companies at least provided margins for those numbers---i.e. plus or minus 3dB. In other words, the M1 would reproduce a 20Hz signal sent to it, but 3dB lower in level than it reproduces a 1kHz signal of the same strength. The numbers you cite mean absolutely nothing without the "qualifying" numbers that need to accompany them. The M1 20Hz figure may be achieved (though I doubt it is) only with 50% harmonic distortion and 20Hz being 20-30dB down from 1kHz. It’s a numbers game that some companies are still guilty of using on the naïve. Though you now think the 20Hz spec for the M1 indicates it plays lower than the B & W, the inverse may actually be the case. It all depends on how those numbers were arrived at. The B & W 35Hz figure may include a frequency response spec of plus or minus 3dB and a distortion spec of 10%, while the M1 figure of 20Hz is achievable only at 20Hz down from 1kHz and with 50% distortion.

Your amp has the same specs as does your CD player? ALL amps and ALL CD players do! Your M1’s are rated at 250 watts? What do you think that means? That the speakers require a 250w/ch amp, or that they shouldn’t be used with an amp producing more power than 250w/ch? It means neither of those things. You say you think you may be pushing your amp too hard because it is rated at 220w while your speakers are rated at 250w. That reveals you are operating with some deep misconceptions about specs. It’s too long a story to go into here, but with some research you will learn why the real amp/speaker pairing considerations are of a very different nature.

If the above sounds overly harsh or critical, don’t take it personally---all audiophiles go through the same learning curve. I remember being very impressed in 1971 with the specs of my new McIntosh 2100 amp---0.25% total harmonic distortion from 20Hz-20kHz at 105w/ch. Even with these much more complete specs than those you are citing, I didn’t learn for another year (thanks to discovering J. Gordon Holt and his Stereophile Magazine in ’72) that those numbers have very little to do with how the amp actually sounds. It is, unfortunately, much more complicated than that.