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Has anyone ever plotted the tweeters upper frequency response limit? My RTA measurements reveal a useable response to at least 20k but that is the instruments highest measureable band and judging by how effortlessly it makes it there, it seems reasonable that it can go yet further up. According to JBL publications, a -10 db point is claimed between 6k5 and 21k5 but at which end, low,high or both? My guess is the lower end.
They drop pretty fast after ~19KHz. Calling it -10dB at 21.5KHz
is a reasonable description of their behavior. In use, I would think
dropping it by 10dB below 6.5KHz (and more as frequency decreases)
when planning crossover design would also be a useful user guide.
The intended diffraction (giving it the wide horizontal dispersion)
appears to be less functional below that freq.
FR Plot of my drivers:
Do you have a calibrated microphone?
Bonjour POS,Quote:
Originally Posted by pos
Oui, les microphones sont integre dans l`appareil.
http://www.phonic.com/en/paa6.html
That is what I was looking for, thank you. What were the instruments used and measuring conditions?Quote:
Originally Posted by neskor
Software is HolmImpulse, mic is Behringer ECM8000 and sound card is M-Audio Fast track pro.Quote:
Originally Posted by Mike F
Behringer is used with generic calibration file found on net, so use this plot as a guide ;)
One day I need to make that calibration file.
There is no such thing as a generic calibration file for the ECM8000.Quote:
Originally Posted by neskor
Look at the measurement of 85 of these mics done by cross spectrum:
Attachment 55129
super machine!Quote:
Originally Posted by Mike F
Here are the measurements of my best matched 2405H pair, using a calibrated mic :
Attachment 55130
Quote:
Originally Posted by pos
Thats about all one could expect from a $99 retail and on sale $49 dollar mic. I sure wouldn't build a crossover or QC drivers with one. I will admit I do have three of them for use in conditions that should one get killed I could shrug it off without care.
That looks a little smoother and a bit softer on top than my measurements with a good mic with a loaded calibration file. On axis 1meter? What power?Quote:
Originally Posted by pos
Thanks Thomas.
This is the smoothest and best matching pair among a batch of 6 brand new 2405HPL drivers.
measurement conditions are as follow:
- ~1m distance (not precisely measured)
- gating around 2khz
- unbaffled 2405, siting on top of a 4412
- FIR brickwall HP filter at 7khz
- unknown but low SPL leval
- calibrated Dayton mic from cross spectrum (should be good within 1dB up to 20khz)
- calibrated tascam 144mk2 sound card