This might be a silly question, but given the same size of their woofer to my HS8 (8'') the main difference in bass presence and strength is measured in W, correct? So 210 W for the Neumann vs 70 or so for the HS8, or are there other factors to consider?
Well, there are.
First of all, you are assuming that both drivers have the same sensitivity, which is not necessarily the case although they aren't likely to be awfully different (likely 88-90 dB / W / m). 3 dB = factor of 2 in power.
More importantly, required driver excursion goes up with 1/f², so eventually you're always excursion-limited in the bass. Again, Xlin may vary. Bass reflex designs will provide extra support in a small frequency range by the Helmholtz resonator.
Here's HS8 max level handling according to
S&R:
The bump at ~80 Hz is likely to be BR related. From about 100 Hz up, things appear to be limited by electrical nonlinearity on part of the driver rather than amplifier power, otherwise 3% and 10% THD graphs would be much closer together. 101 dB SPL only equates to 25 W even if we are assuming a low 87 dB / W / m.
Here's level handling for the KH310A, note 1% and 3% THD rather than 3% and 10% above:
I'd say this guy is primarily excursion-limited throughout the entire bass driver's frequency range (XO is at 650 Hz). Also note how 3% levels are in the mid-100s here rather than the high 90s in the entire mid / upper bass and low midrange, so things are generally looking a fair bit better than for the HS8. The midrange dome appears to be power-limited throughout almost its entire range (a bit of excursion limiting at the bottom) but still is the loudest of the bunch. The tweeter seems to be electrical nonlinearity limited, the drop in its range is likely to follow both a reduction in efficiency (waveguided tweeters usually gain a fair bit on the low end) and increasing influence of driver inductance.
Another thing worth noting: The woofer amp only has to take care of the frequency range up to ~650 Hz, rather than up to 2 kHz in the Yamaha. With separate amplifiers and drivers, the potential for IM distortion is much reduced, and combined level handling increases.
So many colleagues recommended me the Neumann KH 310, but I haven't found a single person that used the Quested V2108, my second choice at the moment mainly for the fact that they are used by Hans Zimmer, Harry-Gregson Williams and the guys at Remote Control.
SOS review of this model
Looks like a more traditional design but still good. 2-way with 8" long-throw woofer + 28 mm tweeter (no waveguide to speak of), crossed over at a low 1.4 kHz, so clearly they were aiming for fairly wide dispersion. I can't imagine the tweeter is entirely happy on the low end of its range, that's the tradeoff for better dispersion. Amplifier power 200 + 200 W, notably with current driving, so driver distortion is likely to be low whenever not excursion-limited. Still, it's only a 2-way that doesn't believe in waveguides, so some compromises are inevitable. I would assume higher bass level handling than in the Neumann, being a BR.
I would say both would be a step up from the HS8 (clearly not bad speakers to begin with but the much lower price obviously has to show somewhere). The Quested would only be my #2 though, and the higher price is not helping matters. Presumably KH310s are being made in substantially higher numbers than the more boutique V2108s... economy of scale and all.
The only area where KH310s potentially need some help is the bass, particularly deep bass <80 Hz (which can be sorted out by wall-mounting and/or adding a sub or two), other than that users have generally noted that these will go very loud cleanly.