Hi;
I didn't realize there was a limit to the notes that would show up on the TEF graph page so I edited it down to show the fourth PEQ filter and corrected the distance to 3M.
The horn driver measurement previously attached has no HF limit. I might after some listening drop a low pass filter on top to tame that peak about 17kHz, if it glares at me.
Below is the transfer function of the four PEQ filters through the DBX260 Besides the 500Hz 24dB Butterworth HP no other shaping or passive devices are in the chain.
The upper line is magnitude and the lower is phase. I didn't change the dB SPL scale on the left to dB V, sorry.
Below is the Plane Wave Tube measurement of
the 2450 used in this setup.
The line that drops like a rock at about 12kHz is phase trace. This is where the diaphragm breaks up and the signal becomes uncorrelated in time form the output. This shows up clearly in the measurement of the horn first posted as well.
Even though I consider the output of these drivers virtually noise at this point, the 2360 sounds better to me with this driver and diaphragm than any other largely due to the fact that you have to push the HF of all other diaphragms even harder via EQ to get them to sound reasonably bright and they sound strained.
The above sentence is of course just my opinion.
Hi Ivica;
There is a fair amount of smoothing on these measurements that takes out the HF hash that would be shown in a raw data measurement. Since we don't seem to hear these very narrow notches (I think this does contribute to listener fatigue) and it is above the fundamental tone of any natural instrument, coupled with the fact that one certainly cannot EQ for such, I smooth it out in the display if there is absolutely nothing I can do to eliminate it at the source.
All the best,
Barry.