Dual driver subwoofers...what say you ??

[Rope]

I'm uncertain where the measurement should be taken. The measurement is from the surround (rubber) of the driver to the base. If I were to measure from the center most point of the cone, It would likely be 3" or more.

Rope

 

[Flint]

It is all about the path the acoustic wave traverses away from the cone. The choke point is exactly the circumference of the effective cone area. Once the pressure wave gets just a tiny distance past that choke point the available cross section area of the wave front is expanding exponentially and no longer an issue.

 

[MatthewB]

Razz no offense taken. The one and only reason for the multiple subs is all the null voids in my akward shaped room. If I could get by with one sub trust me I would. Luckily all my subs have been tuned to perform only what they need to so the bass is tight and well controlled. Heck I was watching "Battle LA" last night and was thinking how tight the bass was with the guns and explosions going off. Watching in my master bedroom "Tron" with just one sub, I can say the same thing. It's just the bedroom has far better shape and acoustics than that horrible great room.

 

[mcad64]

For the same money, dual driver subs are no better than single driver subs.

You could say the exact same thing about woofer size. For the same money, 18" subwoofers are no better than 12" subwoofers.

For example, if you pay $1000 for a dual 12" subwoofer, the performance is likely to be no better than a single 12" subwoofer which also costs $1000. In fact, I would be inclined to believe the dual 12" subwoofer is slightly lower performing because, in general, using dual drivers in a subwoofer is more of a gimmick than a sign of being better performing. Afterall, if a single higher quality woofer can perform equally as good, why bother with a dual woofer at all?

There are only two reasons going to a dual woofer arrangement makes sense:
1) The woofers are already state of the art to start with and the manufacturer wants to best the top of the line single woofer sub they already sell.
2) There is a need to address some physical limitation or goal for the consumer who wants to place a tall skinny (or short and flat) sub where a single large woofer would never fit.

Ok,
So if one were comparing what would have been a state of the art subwoofer from say circa 2004-2007 (PSB Subseries 10) to a new HSU VTF 15F has the state of the art really advanced that much in subwoofer design? What has advanced? Design? Materials? Just trying to decide if a 2011 HSU will be noticeably better than an old (albiet state of art at the time) PSB, which can be had for quite a bit less than the HSU.
Thanks,
Mike

 

[malsackj]

I would like to question on the issue of larger speakers beaming and smaller being more Omni directional. The smaller the room the less beaming would be detected in the larger speakers.

if a larger room 20 x 30 would an 18 be able to present beaming and around what frequency does the 18 present beaming?

with Down fired having the 3 or 4 inch reduce the beaming as opposed to side fired into a room.


Would the IB remove some of the beaming as opposed to an enclosure (samller baffle)?

 

[Flint]

An 18" woofer cone will be 100% omni directional below 188Hz. With a 24" wide baffle half-sphere radiation pattern will not occur at all below 141Hz.

So, for a subwoofer with a crossover setting below 100Hz, directionality, beaming or other such issues won't exist indoors.

A subwoofer would have to be more than 6 feet from any wall in order for baffle step issues to occur below 100Hz.