Same watts at 8 and 4 ohms?

n80 OP
I’m not saying to get the ML2’s, it was used as an example of what does drive speakers.

Your 7B’s drop to 3ohms around 150-200hz not too bad but still needs needs a bit of power there.
But! they are specified as 86db by Aerial, but actually tested by Stereophile at only 84db!!
I would look for a >100w-8ohm amp that can do tested doubling those watts into 4ohms and you should be fine.

Or you can get the $400 3000w Behringer and listen to that, probally not for long.👎

Cheers George

By tested do you mean what the manufacturer will publish (some don't give 4 ohm numbers) or do I need to look for an independent test?

By tested do you mean what the manufacturer will publish (some don’t give 4 ohm numbers) or do I need to look for an independent test?

Test is to me an independent "test" like Stereophile, Soundstage Measurments, Miller Audio Research etc etc.
As amp manufacturers "specs" sometimes/mostly fudge their specs.

If they don’t give the 4ohm wattage numbers, then either the amp doesn’t look good doing them(like the heading of the thread) or goes backwards even from the 8ohm, or it simply can’t handle it at all, and turns off or blows a fuse.
Look for reviews that give bench test also


Cheers George

Hi George,

Take a look at any speaker review on Stereophile and they will plot the speaker impedance.

This impedance is never a flat line at 4 or 8 Ohms and in fact take quite complicated shapes.

The lower the impedance, the more current the amp has to produce to maintain a stable output, otherwise it starts to drop.  If you think of a wall wart, 12V, 2 Amps.  If you try to draw more than 2 amps, it no longer produces 12 V but instead the voltage sags until it overheats.  Amps do the same thing.

An ideal amp maintains the voltage output regardless of speaker impedance, which is synonymous with saying it doubles the wattage as the impedance is cut in half.

You may not need an ideal amp or like how it sounds matched to your speakers though, so keep this in mind.  The C 388 uses a hybrid Class D designed by Bruno Putzeys (or nCore?) which is a pretty sweet little thing. It puts a linear amp in the middle of the Class D.  I have another NAD integrated with it and I like the sound a lot.  It's not as fun to listen to as my Luxman, but nothing wrong with it either. 

Nice lesson ,to pass the time ...higher efficient speakers less power.To each his own.