2. misc-audio
  3. 135264-88409

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
erik_squires
16,046 posts
 
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
bdp24's avatar
bdp24
9,788 posts
 

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.

onhwy61's avatar
onhwy61
5,215 posts
 
The Mirage M1s are flat down to 30Hz and roll off to down 6dB at 25Hz, which is very respectable low base performance.  If the GAS is getting too hot and regularly shutting down, then there is probably something malfunctioning in the amp.  I say this assuming you are not listening at 110dB.

The 2006 Stereophile review with measurements.
jamesfokes's avatar
jamesfokes OP
30 posts
 
Thank you all so much for these responses! I am rearranging my whole system. Particularly Jond for the words about the default setting on the MC8. You are exactly correct< if I had a hat it would be off to you and all the other responders. You probably saved me fifteen thousand bucks! I was seriously considering the MC302 and some B&W speakers. I can't thank you guys enough!

jamesfokes's avatar
jamesfokes OP
30 posts
 
PS, I was told by the repair guy at Audio Advice in Raleigh that the M1s were good for 250 RMS with 500 watt peaks, but biamping was giving me 500 RMS and one thousand watt peaks, he said that was what cooked my tweeters.
More to discover