BMS states 132db @80watts as max SPL for the 4550. It doesn't say where its crossed. I'm aware that peaks in its response which is more irregular than the DE250, will contribute to a false reading.
Thanks Earl. Its good info to know.
It seems from this and other posts make my SPL concerns unwarranted. I'm tired of burned out tweeters. I guess its trauma.
since the BMS 4550 is getting the better votes here, sounds like it might have trashed the TAD completely
makes me wonder if the BMS4550 is still better than the DE500
... just joking 
How could that be? Wouldn't the complete circle have more area than an annulus?
I read that the 4550 was a ring radiator and they are more efficient because of less mass but I dont think it could be more SD.
All your questions will be answered here:
1 inch CD Comparison (SEOS18)
I did a comparison between 4 one inch CDs. I thought the BMS was slightly smoother and had slightly more bottom end extension.
1 inch CD Comparison (SEOS18)
I did a comparison between 4 one inch CDs. I thought the BMS was slightly smoother and had slightly more bottom end extension.
Thanks for that nice link.
I read in this thread that "Even Earl Geddes and other speaker designers did testing on them. They're good to go."
I would normally not critique someone else's product, but this case is unique. That's because what the author failed to note was that I rejected his product. This quote makes it sound like I approved of it. Using my name is one thing, but claiming I said the opposite of what I actually said is unacceptable.
I read in this thread that "Even Earl Geddes and other speaker designers did testing on them. They're good to go."
I would normally not critique someone else's product, but this case is unique. That's because what the author failed to note was that I rejected his product. This quote makes it sound like I approved of it. Using my name is one thing, but claiming I said the opposite of what I actually said is unacceptable.
That's an interesting comparison.
A friend has BMS4550s on his horns (well-damped Altec 511s), and after EQing them reasonably flat, they're mighty fine sounding drivers. The 4550s weren't entirely happy with an 800Hz LR24 crossover, but once he moved the crossover up to 960Hz they work well at any listening level we've tried.
Originally Posted by weltersys
AFIK the annular 44.5mm diaphragm BMS has slightly more Sd than the dome B&C 44mm diaphragm.
A quick search does not find the actual inner and outer diameters of the annulus, but my driver testing
http://www.diyaudio.com/forums/multi-way/212240-high-frequency-compression-driver-evaluation.html
found it's output to be a bit more (in the OP's desired pass band) than a 2" dome shaped diaphragm driver, and less than a polyester surround B&C 3" titanium diaphragm driver at similar distortion levels.
I may be mistaken regarding the Sd of the B&C DE250 being smaller than the BMS 4550, but regardless of the reason, the " 1 inch CD Comparison (SEOS18) " referenced in the past few posts does agree with my previous statement that the BMS 4550 can get a few dB louder with less distortion.
Art
AFIK the annular 44.5mm diaphragm BMS has slightly more Sd than the dome B&C 44mm diaphragm.
The annulus (doughnut shape for those wondering) is on either side of the 1.75" voice coil, so though it lacks a center, extends outward in diameter from the voice coil, so depending on the width of the annulus, could have more (or less) Sd.
A quick search does not find the actual inner and outer diameters of the annulus, but my driver testing
http://www.diyaudio.com/forums/multi-way/212240-high-frequency-compression-driver-evaluation.html
found it's output to be a bit more (in the OP's desired pass band) than a 2" dome shaped diaphragm driver, and less than a polyester surround B&C 3" titanium diaphragm driver at similar distortion levels.
I may be mistaken regarding the Sd of the B&C DE250 being smaller than the BMS 4550, but regardless of the reason, the " 1 inch CD Comparison (SEOS18) " referenced in the past few posts does agree with my previous statement that the BMS 4550 can get a few dB louder with less distortion.
Art
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Not a cone, an annulus
.Correct, until someone posts dimensions of the annulus, we don't know SD, but since the specs between the two drivers are nearly identical (given the difference in test horns), I think it's is safe to assume the diaphragm is the same SD.
The exit has been changed to fit 1.5" horns without requiring more "plumbing".
Svetly Alexandrov from BMS wrote here
www.pa-forum.de • Thema anzeigen - BMS Trennfrequenzen
outside diameter 56mm
Sd 1660mm²
At 1660mm² it would have about 8.44% more Sd than the B&C DE250, at 1520mm².
Seems correct, given the measured output differences.
Diaphragm size matters when excursion is kept small, as it must be for HF drivers to have extended HF.
Thanks for posting that, now I just wonder where I'd seen it before, since I don't normally attempt to read German...
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