The B&C 8NDL51 seems like an obvious choice. I used it in a car project in 2006. Smooth response, low distortion, high sensitivity, great power handling.
Why are you setting the cut off at 200hz? The 8" aluminum cone woofer from Parts Express will play to 50hz and costs less than the B&C.
I have both of them here; I would use the PE. (Keep in mind I don't like three-ways.)
Alu cone 8"er from PE, this one?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-366
Seems a good driver, but its 88dB/w/1m is not quite "hi efficient"
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-366
Seems a good driver, but its 88dB/w/1m is not quite "hi efficient"
Alu cone 8"er from PE, this one?
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-366
Seems a good driver, but its 88dB/w/1m is not quite "hi efficient"
Ah true, I missed the part about "high efficiency" LOL.
My Summas uses a 15" high efficiency woofer and it requires subs to fill in the last two octaves.... Couldn't even imagine using a 8" woofer. Too small! (Unless you can live with an F3 of 200hz...)
In a wide enough baffle, an 8" would go as low as you want. The problem with mounting the midrange 70-80 cm above the floor is that you will get a giant suck-out around 300 Hz caused by the floor reflection. Since you will get almost no other early reflections, you wont get any help to fill in at 300 Hz either.
I found with my dipoles that the 8" Excel W22 actually was flat down to 80 Hz, but with a giant 25 dB hole centered at 300 Hz.
The floor reflection is why you should cross over at 300 or even higher. With a woofer mounted close to the floor you will avoid the floor reflection problem.
I found with my dipoles that the 8" Excel W22 actually was flat down to 80 Hz, but with a giant 25 dB hole centered at 300 Hz.
The floor reflection is why you should cross over at 300 or even higher. With a woofer mounted close to the floor you will avoid the floor reflection problem.
At least on paper the Audax HM210 Z10 looks "close to spectacular", and there are reports that it holds in real life. Again, not a driver to be crossed over very low....
Floor bounce was adressed already and IME there are only two ways to fix it: Don't exite it or have proper acoustical obstactles in its way (and a rug won't help, although "it really ties the room together" like the Dude would have said).
DSP room correction in theory can fix it to a reasonable extent (unless the reflection is close to 1:1 ratio in level with the direct sound), but only for a head-in-a-vice listening pos and with quite a bit of side-effects.
- Klaus
Floor bounce was adressed already and IME there are only two ways to fix it: Don't exite it or have proper acoustical obstactles in its way (and a rug won't help, although "it really ties the room together" like the Dude would have said
).DSP room correction in theory can fix it to a reasonable extent (unless the reflection is close to 1:1 ratio in level with the direct sound), but only for a head-in-a-vice listening pos and with quite a bit of side-effects.
- Klaus
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At least on paper the Audax HM210 Z10 looks "close to spectacular", and there are reports that it holds in real life. Again, not a driver to be crossed over very low....
Floor bounce was adressed already and IME there are only two ways to fix it: Don't exite it or have proper acoustical obstactles in its way (and a rug won't help, although "it really ties the room together" like the Dude would have said
DSP room correction in theory can fix it to a reasonable extent (unless the reflection is close to 1:1 ratio in level with the direct sound), but only for a head-in-a-vice listening pos and with quite a bit of side-effects.
- Klaus
Kinda irregular impedance curve on that Audax.
Does this floor bounce thing count for normal boxed speakers as well?
Yes, absolutely. There is at least one good reason that mid/woofer XO is usually placed higher than 300 Hz in 3-way speakers.
Yes, but unless the CSD were completely smoothed beyond recognition the resonances at 1.5kHz++ don't seem to show up excessively, which is a claim of the cone material. There might be distortion peaks at those freqs, though.
I mentioned this driver because it is high sensivity and fits your price range.
Other candidates would be some PHL E20 series models, but those tend to be a bit ragged in the breakup region (for those to whom this is a very important criterion) -- way more than the Audax. And more costly...
- Klaus
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mfg specs are usually measured after a several hour preconditioning at full rated power.
I suspect the unit Brandon used was not fully broken in. At least the data seems to suggest this (higher Fs, higher Q's)
- Klaus
BTW: I found a more detailed datasheet of that Audax driver:
http://www.cad-audio.com/hm210z10.pdf
This one looks more reasonable wrt CSD plot
I suspect the unit Brandon used was not fully broken in. At least the data seems to suggest this (higher Fs, higher Q's)
- Klaus
BTW: I found a more detailed datasheet of that Audax driver:
http://www.cad-audio.com/hm210z10.pdf
This one looks more reasonable wrt CSD plot
Actually I just retested 8NDL51, and after quite a bit of high excursion xmax testing the Fs was still about the same as when I tested it a year ago. Didn't do TS with my newer (better) method though. But sometimes the numbers are misleading when just glancing at them. Model the bass response with both TS and see if they really do differ.
One thing I can say is the one real "proof" I have that the numbers are right is when I do the xmax testing. If the TS are correct the predicted excursion will be correct for a given voltage. The B&C 12HPL76 and AE TD12M I tested in June were the two drivers that did not prove out very well. Both needed considerably more voltage to reach the given excursion than the model would suggest. Over 1 volt more. It's difficult to say how much more break-in would have changed things. The well used TD15X I also tested didn't need as much voltage as the model predicted so who knows how the 12HPL76 and TD12M would have been with much more break-in. The 18Sound and Eminence were within tenths of a volt of the predicted value after the slight break-in I do to all drivers.
One thing I can say is the one real "proof" I have that the numbers are right is when I do the xmax testing. If the TS are correct the predicted excursion will be correct for a given voltage. The B&C 12HPL76 and AE TD12M I tested in June were the two drivers that did not prove out very well. Both needed considerably more voltage to reach the given excursion than the model would suggest. Over 1 volt more. It's difficult to say how much more break-in would have changed things. The well used TD15X I also tested didn't need as much voltage as the model predicted so who knows how the 12HPL76 and TD12M would have been with much more break-in. The 18Sound and Eminence were within tenths of a volt of the predicted value after the slight break-in I do to all drivers.
Its been mentioned before, tho it looks very much like 5db graph steps to me
And B&C graphs to me really looks like something they have made by hand with a pencil
Is there a clear difference in how they measure, nearfield vs farfield
Hard to believe the B&C is that smooth in nearfield
And maybe the Beyma isnt that rough in farfield
But admitted, small drivers doesnt seem like a Beyma strength
PHL seems more attractive, and many to choose from
But hard to find any response measurements
But honestly, none of the pro 8" with more than 90db SPL seems to be of little use outside 500-1000hz, really
I dont know why the cheap cheap Beta-8 seem to shine where others fail , but maybe only on paper, I dont know
But strange creatures, these small pro drivers
Even if they are high SPL and completely dead below 500hz, they still always seem to have rather poor top range
Obviously they focus on high SPL and powerhandling, rather than smooth response
Maybe best remember that they are mostly made fore farfield use in arrays, open air
And I really dont know if the term BSC even exist in pro sound world
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