Class D and High Efficiency Speakers?

There is really no inherent sonic advantage to Class D, aside from the ability to deliver a LOT of power, and a whole lot of potential problems, most if not all that can be handled by proper implementation. But, if one does not need a whole lot of power, why go Class D?

I got to hear a $14,000 Rowland Class D amp on my friends 106 db/w efficient speaker system. The sound was quite unsatisfactory -- no top end air, oddly sterile and bland sound, lacking in full harmonic structure -- this in comparison to some very good pushpull tube amps (45s). Tubes, generally speaking, sound terrific at low power outputs and have problems with higher power; transistors seem to be just the opposite.

There are a lot of very good speakers that need a bit of power; a Class D amp would be more suited for that application.

I am running a pair of NuForce 9 SE V2 to drive my Coincident Eclipse 111. The speakers have an efficiency of 94 db. The sound is spectacular. I chose the NuForce amps for the quality price ratio.

I would suggest taking up NuForce on their offer of a free (or almost free) trial of the amps to hear them in your own system. FYI, they are really not a class D amp. See the web site for further explanation.

I can't think of a good reason to use class d amps with horns unless you're the adventorous type.

IMO you'd lose much of the "warmth" without the tubes.

Borrow some digital amps and give a listen. It may be your cup of tea.

High Efficiency speakers in general prefer an amplifier with a relatively high source impedance, due to the reactive nature of high efficiency drivers.

The use of low output impedance amplifiers with high efficiency drivers is the reason why horns have a reputation for being strident.

If you really are intent on this, add an 8-ohm resistor in series with the speaker load. True, you will dissipate likely up to 50% of your power in the resistor, but it will simulate (somewhat) a higher source impedance.

Or- you could get a tube amp. You won't need a lot of power. In the case of a high efficiency speaker, a good tube amp will clean the clock of any class D amplifier made.