Hi Mike.
Interesting.
There are few things to consider.
1/ I can see that the Harbeth claim of the 40.2 being "easier to drive in the bass" compared to the 40.1 seems to be only marketing
2/ With the 40.1, one needs super high level isolation from the ground and from their stands. I use Skylan stands with premium fill. But the speakers are isolated from the stands with Nickel Manganese housings and ceramic bearing anti vibration feet ( AVF) from PAB and the stands are isolated from the ground with acrylic and steel bearings PAB AVF.
In my 28 m2 room, all visitors are extremely impressed with the bass response. It is clean, deep, tight and textured. But :
- the bass of the 40.1 goes VERY low. Much more than the Alexias for example. With more energy. This can make the speaker very difficult to integrate in many rooms if you intend to use it in a conventional hifi way : ie, playing at rather high volume, let's say above 90dB. You can do it, but you need a really perfect room treatment. If not, you have to keep in mind that these speakers are originally studio monitors, made for near field listening at low volume. 70 / 75 dB maximum.
- Many amps are not perfectly flat and right below 30 Hz. If such an amp is used with the 40.1, then you will hear a clear distortion. And it is not a question of power. It is a question of right frequency response. My Nagra MSA is only 60W and gives the best bass from the 40.1. The Shindo CCQs go lower, with more energy but with less control. The bass gets very invasive at high volume. Not boomy but just overpowering the room and eating the mids and the treble. At low volume, below 70dB, my Shindo CCQs are just a heaven with the 40.1. Once again, when those speakers are used like they are intended to ( you cannot use them as Magico or Wilson speakers), if a quality amp is used, along with decent isolation, you will get a superb and quite unique bass. Much better imho than the bass of the heavily damped speakers like Wilson, Magico, Rockport and so on.
But remember, if not properly isolated, the speaker will sound clearly boomy, no matter the amp used.
An option can be to use a low power amp but of very high quality. It will not give enough energy in the extreme bass to create room resonances : there will be a steep attenuation below 40 Hz that will appear as a good thing in many rooms, especially if you want to listen at high volume. The McIntosh 225 is my favorite amp for that use. Also, some recordings are extremely compensated in the bass, with a heavy loudness effect. They are actually mastered for "lay sytems" and ipods. Small speakers.
The 40.1 will give you exactly what is on the recording. Some recordings will sound boomy just because that is precisely what the sound engineer made.
Now, you will never get with Harbeth, or any other speaker, the naturalness and speed and clarity of the bass of a 30 or 38cm Altec driver. Those incredible drivers do not go as low as the 30cm of the 40.1. In fact there is no extreme bass at all. But, At 45/50 Hz and above, they are just the best bass drivers ever made. But yes, they are not made for electric rock. They are made for acoustic instruments.
