DanWiggins
Second Unit
- Joined
- Aug 15, 1999
- Messages
- 324
Hi all,
XBL^2 is being considered by many individuals in the audio community, including several of the original designers of other drivers discussed here. It's also rolling in many products right now, some of which the licensees have chosen to keep quiet.
As compared to some of the prototypes from TC Sounds (which use a variable winding approach, discussed in our own patent), XBL^2 offers as much if not more linear stroke, much lower moving mass, much lower inductance, and overall tighter motor tolerances (greater clearance when rocking). Additionally, it's considerably less expensive to build. And from a dynamic linearity standpoint, BL and Le are much more linear, and because of the lower weight Cms tends to be much more linear as well.
Linear stroke is good, but it should be usable as well. Having 400+ grams of voice coil weight severely restricts your options in use of the driver, as does inductance in the 10+ mH range. That is the reason that even though these prototypes have high BL^2/Re numbers, they have extremely high Qes values (approaching a value of 1). Extremely high mass to achieve that level of throw. The motor is strong, but not strong enough, and the result is a very high Qes of a highly underdamped system.
There's a lot more to drivers than just BL^2/Re, or even linear Xmax. Linearity of BL, Le, and Cms are also important, as is moving mass. Having a high BL^2/Re is worthless if you achieve it via high mass, and need a stiff suspension to keep that mass centered. It's like installing a 500 HP engine in your car, but mandating that you must drive with your parking brake on, and while towing a 2500 pound boat. Better to stick with no brake or boat, and a 300 HP engine.
Dan Wiggins
Adire Audio
XBL^2 is being considered by many individuals in the audio community, including several of the original designers of other drivers discussed here. It's also rolling in many products right now, some of which the licensees have chosen to keep quiet.
As compared to some of the prototypes from TC Sounds (which use a variable winding approach, discussed in our own patent), XBL^2 offers as much if not more linear stroke, much lower moving mass, much lower inductance, and overall tighter motor tolerances (greater clearance when rocking). Additionally, it's considerably less expensive to build. And from a dynamic linearity standpoint, BL and Le are much more linear, and because of the lower weight Cms tends to be much more linear as well.
Linear stroke is good, but it should be usable as well. Having 400+ grams of voice coil weight severely restricts your options in use of the driver, as does inductance in the 10+ mH range. That is the reason that even though these prototypes have high BL^2/Re numbers, they have extremely high Qes values (approaching a value of 1). Extremely high mass to achieve that level of throw. The motor is strong, but not strong enough, and the result is a very high Qes of a highly underdamped system.
There's a lot more to drivers than just BL^2/Re, or even linear Xmax. Linearity of BL, Le, and Cms are also important, as is moving mass. Having a high BL^2/Re is worthless if you achieve it via high mass, and need a stiff suspension to keep that mass centered. It's like installing a 500 HP engine in your car, but mandating that you must drive with your parking brake on, and while towing a 2500 pound boat. Better to stick with no brake or boat, and a 300 HP engine.
Dan Wiggins
Adire Audio
