How much faster of a sub is the REL T5X vs SVS SB12-NSD

The notion of a "fast" subwoofer is entirely inappropriate. The speed a subwoofer can vibrate at without distortion is it's frequency response at a given volume. A smaller driver is at a distinct disadvantage because it has to travel farther (faster) to produce a given low note at a given volume than a larger driver. As a rule, larger drivers have less distortion than smaller ones and do not have to travel a far (faster) to produce a bass note at a given volume. Producing 18 Hz with authority requires at least four 12" or two 15" drivers in your average listening room. In a 16 X 30 foot room I use eight 12" drivers. This is a two channel system.

["curiousjim     I also tried, Velodyne, REL(old models) and an old SVS12” and the last is a brand new SVS 2000Pro. Depending on your room, you can probably get close, but…."]

Interesting problem. Do you recall which Velodyne model you tried?

The notion of a "fast" subwoofer is entirely inappropriate. The speed a subwoofer can vibrate at without distortion is it’s frequency response at a given volume. A smaller driver is at a distinct disadvantage because it has to travel farther (faster) to produce a given low note at a given volume than a larger driver.

I agree, but people who have never wielded a pencil in anger on a math, physics or EE test, or who are into the humanities or business side of things, like to use the term “fast” more likely to describe what is “transient response”.

And faster is also easier to spell than transient.

In this respect, sealed —> ported —> bandpass, and they sound faster as the transient response and group delay are lowest for sealed.

• sealed = 2nd order
• ported = 4th order
• bandpass = 6th or 7th order

Transmission line is likely 3rd order, so it slots in, and infinite baffle I believe is 1st order.???