More power for moderate listening levels?

Much to sort through here. I thought the thread might die after a few posts but the community here really came through. Thanks all. 

I owned the Harbeth SHL5+ for many years and they sound great at moderate volume as well as loud volume. I bought the Harbeth's because I sold my house and they played well at lower volumes unlike the Vandersteen Quatro's I had before.

I successfully used an Ayre AX-7e in combination with an Ayre Codex and in my 15 x 21 x 9 room I could not crank the volume loud enough to cause any distortion. The Ayre is only 60 watts and still drove the SHL5+ well. I upgraded to the Aesthetix Mimas integrated, which puts out 150 watts a channel, and that was even better. So I am not sure that more power is the answer you are looking for. Alan Shaw says that any 100 watt+ amp should work on any of his speakers. I would suggest trying a few different amps to see what works best with the Harbeth's in your room.

I did try the Pass 250.5 amplifier along with the Audio Research LS26 preamp and I did not like it with the Harbeth's. Nothing against Pass, just not my cup of tea. Sounded great with my Quatro's though.

Good Luck!

Using an SPL calculator you should be able to achieve 97 to 100dB levels at your normal listening position.  The Pass amp is rated at 50 watts peak power.  Personal taste differ and some would not consider this level very loud.  I suggest you use an SPL meter to gauge how loud you listen and at what point your system starts to sound strained.

It’s an experiment that I want to try. Also, just using my ears to Identify acceptable listening levels at my chair. Could save the strain on my amp as well as my wallet!

As more power is fed to the voice coil, it heats up and that heating increases resistance which reduces the amount of power that can be delivered to the driver. The less efficient the speaker, the greater the compression.

Horsefeathers. Very efficient speakers have wimpy motors that may not control the cone as well as a less efficient speaker. The voice coil has to get to ≈90°C for a 1db reduction. While voice coil heating effect is measurable, it is difficult to detect. Our ears begin self-preservation clamping at elevated levels, which some may interpret as voice coil heating compression.

see http://www.ielogical.com/Audio/WinterBlues.php#TheFly for a bit on voice coil heating.

@brianbiehs:
Install an app like AudioTool on your phone and get some real measurements as to the levels you are reaching.

25wpc at 2.6m [8.5ft] max out @ 95db PEAK on 86dB/W/m speakers. At 5m [16.5ft] max level is 89db. Add room noise from a bunch of people and the apparent level will be somewhat lower.

Be aware that changing amplifiers to support Disco may severely compromise audio quality at less taxed listening levels.

More speakers are blown by party levels than almost all other causes combined.

There is no free lunch!