alexclaber
Commercial User
Wow that is different than what I would have thought. When I've modeled a ported enclosure with a driver that has a sizeable group delay (>12msec at 50 Hz), reducing box volume tends to reduce this delay which I thought was related to how coherent and defined the low end is. The tradeoff is reduced low end sensitivity but you are less likely to bottom out at high power - kind of like having stiffer springs in your suspension. Perhaps that's too simplistic.
It isn't really the driver that has group delay, it's the system of driver and cab (and amp). Group delay is a measure of the rate of change of phase response of a system, which itself is very closely linked to the frequency response of the system. So in the case of the Super Twin you have a smaller cab which is tuned less low, so there is a sharper 'knee' in the response curve - that gives it a slightly more 'thumpy' tone, part of which is due to the change in transient response (which is closely linked to group delay). The Big Twin 2 has a larger enclosure and deeper tuning frequency so the response curve has a smoother roll-off which gives you deeper lows and quicker transient response.
Regardless, that 12XN550 driver looks incredible. Deeper and tighter with adjustable high freq is very attractive for the Big Twin 2. If you have a tube preamp which imparts some nice harmonics and a little give to the feel and add a bump around 120 Hz can you still get a good traditional vibe with this cab?
Yes, it's very much a case of you getting out what you put in, so if you get an old school vibe happening from your bass and amp it'll translate that very well.