Hi,
RobH raises an important point on which I've commented previously--that our hearing sensitivity to low bass at lower volume levels diminishes very rapidly, much faster than our response to midrange and high frequencies.
It's perfectly legitimate to at least try the bass control on your amplifier to see what 3 dB or 5 dB bass boost will do to your M3's bass output. Depending on the "hinge" point of the bass control circuit, it may provide an enjoyable lift in deep bass output without any significant coloration of upper bass such as male vocals.
The idea of never touching tone controls grew out of a misguided British notion that tone controls add distortion to the audio signal. Well designed ones do not, unless you consider a deviation away from flat frequency response a "distortion". And here's the irony: some of the earliest really good tone control circuits were designed by a British engineer, Peter Baxandall.
The M2s, M3s, and M22s will accept 3 to 6 dB of bass boost with ease, and, depending on the room and setup, it may nicely compensate for any perceived bass losses. Older stereo intergrated amplifiers and receivers almost always had a "Loudness" control in addition to the volume control. The Loudness control automatically boosted bass by increasing amounts to compensate for human hearing's loss of bass sensitivity at lower listening volumes.
Regards,
