This little beast seems to be able to put out 90 Hz to 20 KHz with peaks of 124 dB! I have not seen an 8" coaxial with the specs to do this, without significant compromises... I know that this speaker is widely in use in post production studios and smaller cinema theatres, I'm guessing that it's not all all wrong...
Any reason the thing should not work well in a stereo situation with a suitable sub? The 120 x 120 dispersion might be problematic in untreated rooms, I guess - but room reflections should not be a problem at my studio... could it even be an advantage?
Any reason the thing should not work well in a stereo situation with a suitable sub? The 120 x 120 dispersion might be problematic in untreated rooms, I guess - but room reflections should not be a problem at my studio... could it even be an advantage?
Piston Excursion calculator
124 dB peaks at what frequency?
To output 124 dB peak at even 150 hz, an 8" piston will require some 12 mm one way xmax, a very un-likely scenario for a co-axial.
At 300 hz, it's likely able to produce 124 dB with just 3 mm of excursion, given appropriate loading conditions.
No magic, just physics at work.
If one were attempting to power this device to peaks of 124 dB, it wouldn't take long for compression to rear it's ugly head, lowering overall long term acoustic output.
124 dB peaks at what frequency?
To output 124 dB peak at even 150 hz, an 8" piston will require some 12 mm one way xmax, a very un-likely scenario for a co-axial.
At 300 hz, it's likely able to produce 124 dB with just 3 mm of excursion, given appropriate loading conditions.
No magic, just physics at work.
If one were attempting to power this device to peaks of 124 dB, it wouldn't take long for compression to rear it's ugly head, lowering overall long term acoustic output.
It's actually 118dB with a bit of crest factor added.
Edit: spec sheet says that is a pink noise test based on AES power handling rating.
Edit: spec sheet says that is a pink noise test based on AES power handling rating.
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I like how they specify "250 W 2 hrs, 200 W 100 hrs". 100W RMS forever!
No, I dont know of any other 8" that can do that -
Drool, drool - JBL!
No, I dont know of any other 8" that can do that -
Drool, drool - JBL!
Yep, as you say....
Here's another 8" coaxial from a manufacturer that provides probably the most detailed/best spec sheets I've seen in the marketplace.
https://www.fulcrum-acoustic.com/wp-content/uploads/2019/08/Prod-Spec-CX896-v12.pdf
They give both processed and raw specs, along with response graphs for both, which I think is really cool. (and full sets of polars)
For this one:
Nominal Maximum SPL (peak / continuous)
134 dB / 128 dB
Equalized Maximum SPL (6) (peak / continuous)
124 dB / 118 dB
footnote (6). says:
6. Equalized Maximum SPL The 1-meter-referenced SPL produced when an EIA-426-B signal is applied to an equalized loudspeaker system, at a level which drives at least one subsection to its rated power.
Haha...even with such unusual disclosure, it still ends up being a one subsection spec huh?
@diyuser2010 - thank you for the link to the piston excursion calculator... it is a great resource for a noob like me. As usual, if something looks too good to be true, it probably is.
Good thing is, looking at the calculator, I seem to be on track with my other idea using Beyma 8CX300Fe and Lab12c...
@ billshurv... RMS/IEC/AES = confusing for a noob like me. What would be the correct way to describe average and peak potential of this speaker, in dB SPL, 'C Weighted'?
Good thing is, looking at the calculator, I seem to be on track with my other idea using Beyma 8CX300Fe and Lab12c...
@ billshurv... RMS/IEC/AES = confusing for a noob like me. What would be the correct way to describe average and peak potential of this speaker, in dB SPL, 'C Weighted'?
A good question and not sure I can give a sensible answer other than it would certainly be loud enough for me! I really don't know how those test scenarios match reality, but it's certainly enough to meet THX specs in a decent sized room, so 85dB=-20dBFS at the listening position with a chunk of extra headroom. 150W/channel should do nicely as long as clients don't bang head too much.
But sure someone better versed in the art can give a more accurate assessment.
But sure someone better versed in the art can give a more accurate assessment.
The magic happens in the brain of whoever writes the "specs" or, especially, the advertising copy 😀
Don't use any SPL weighting, just go with flat(Z).
Slow for average, fast for peak.
That will translate into the most commonly given specs,
Slow for average, fast for peak.
That will translate into the most commonly given specs,
RMS = Root Mean Square.
Not actually technically correct to use for power (it could be calculated but it's useless)
Usually means the apparent power calculated from the RMS Volts measurement.
For a resistance this will equal the actual power, so that's the usual use.
AES = Audio E. Society.
Is a nominal power that is convenient to pair amplifiers with speakers.
So an amplifier capable of 100 W into 8 ohm can be connected to an 8 ohm nominal speaker rated for 100 W.
After a while the speaker heats up, the actual resistance increases, the actual power will be less than 100 W but the speaker can absorb the power of the 100 W rated amplifier.
Best wishes
David
Pro speaker manufacturers have many 8"coaxials with a compression driver
eg. Pro Coaxial Full-Range Speakers - Parts Express
Eminence Beta-8CX 8" Coaxial Driver
B&C 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm
eg. Pro Coaxial Full-Range Speakers - Parts Express
Eminence Beta-8CX 8" Coaxial Driver
B&C 8CX21 8" Professional Coaxial Speaker 100 x 100 8 Ohm
The Faital 8HX230 would probably do it. I had the 10" version put up a 125dB nominal sine sweep. I believe the 8" is cut from the same cloth, so would expect similarly impressive results.
Chris
Chris
Simplified physics for a point source radiating in 4π space. That hardly is the case with a 8" coax measured on 1m axial. Change the 4π to 2π in the equation and you'll have more of a direction. But it was very useful to bring the math here instead of the speculations, so kudos.
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I believe that calculator assumes 2pi radiation, and the assumptions of the "simplified physics" hold just fine at low frequencies.
Chris
Chris