For efficient speakers, how much difference does an amp really make?

Mapman.....TechHiFi....boy that brings me back....

Just to be clear, 90-93dB is a moderate efficiency.


The problem you run into with moderate to lower efficiency speakers (less than 89dB) is something called 'thermal compression'. This is the tendency for the voice coil to heat up dynamically on peaks, which limits power with many amplifiers. The more power you throw at it, the worse it gets. This is why efficiency speakers (+96dB) have greater dynamic punch.

It’s true that listening at too high an SPL continuously beyond ~ the mid 80s causes hearing loss, so if one is armed and dangerous with an amp/speaker combo truly capable of delivering clean, dynamic peaks in the 90s or greater like one might hear at a live concert, be careful. There is only so much of that really good stuff the human ears can handle.

Soft clipping lower power tube amps are a good compromise from that perspective. Your ears are safe and as teh soft clipping kicks in rolling of the dynamic peaks, you will probably hear more of all the rest that is in the recording. That’s still a lot of good music.

Hate to make soft clipping amps sound similar to modern loudness wars recordings but the end result can be very similar.

Disclaimer: I like a lot of modern loudness wars CDs with good material done well otherwise, but only on a  good suitable powered setup capable of delivering the goods.

+1 @atmasphere 

To add to Ralph's (Atmasphere's) comment, based on the specs shown at the end of this document the 93 db figure is based on 3 db of anticipated "room gain." The anechoic figure is 90 db, which IMO is probably what should be relied on when comparing the specs of this speaker to those of others. Also, the impedance curve shown near the end of that document indicates an impedance of about 5 ohms for most of the region below 1 kHz, where the majority of amplifier power is typically required. Sensitivity of 90 db/2.83 volts/1 meter corresponds to about 88 db/1 watt/1 meter for a 5 ohm load, which is definitely not high efficiency.

That said, the relatively flat impedance curve and the relatively small impedance phase angles at most frequencies suggest that this speaker should be fairly versatile in terms of amplifier selection. I wouldn't want to speculate, though, on how much of a difference you are likely to hear in your particular system going from the Outlaw to another amp you may consider. I would just say that the difference is likely to be less than it would be if your speakers had particularly challenging impedance characteristics.

In any event, kudos to Ascend for providing the detailed information they have provided in the paper I linked to.

Good luck. Regards,
-- Al