Originally Posted by tuxedocivic
I just took a look at the product page for the 4550 and BMS says it's good for a 800hz cross over. That's SEOS15 territory, but the response graph falls like a brick below 800hz. Not sure how easy it would be to cross down there. I find the DNA-360 a pretty capable CD. I cross the DNA-350 at 950hz in my personal speaker, and it's not a problem. What does the 4550 offer over the DE250 or DNA-360?
I think the reason for the drop below 800hz on the product page is due to the horn, not the driver. I have used these drivers to 800hz with good results.
I have some customers who have used them lower, but I know they may not meet power or distortion specs below this point.
This is also the case with the 4552. It is rated to 1Kz, not 800hz, even though they both have the same VC (voice coil) and membrane. The reason is that the 4552 is a smaller driver (neo vs. ceramic magnets) and the 4552 opens up faster to get to the 1" throat size.
So it has more distortion below 1Khz.
In answer to your last question. All BMS drivers are a ring radiator diaphragm design, the B&C is a full dome diaphragm.
As such, the VC on the BMS only has to control a very small length of diaphragm at any one point.
It also gives less room on the BMS diaphragm for break up, or standing modes. Also, since the VC is in the center of the diaphragm, and not ringing the outside, even though they both have 1.75" VCs, the BMS will have more diaphragm surface area.
So you will get better transient response, less over ring, and higher sensitivity from the BMS.
In my opinion, generally speaking, the B&C drivers will have a flatter frequency response, the BMS will have better dynamics, and a more detailed and smoother sound.
Regards, Jack Arnott