|While the PRV D280Ti compression driver works well with the PH565 horn, I am still not completely satisfied with the flatness of the response.
This time, I screwed on a compression driver with a smaller Voice Coil diameter, a Peavey RX14. All the previous three voice coil diameters are about 1.7″, whereas this RX14 is 1.4″
Fig 1 shows the behavior of the RX14 with the PH565.
BLACK trace = RAW (no crossover, no CDEQ)
Fig 2 is the summed response (Red trace) of a Dayton RS180S with the Peavey RX14/PH565 combo. Electronic crossover set at 2kHz (24dB/oct). CDEQ not activated.
Severe cancellation is observed to the right of the crossover frequency. Microphone at 1 meter tweeter axis, Gating at 5 msec, No Smoothing applied.
|Peavey RX14 wired in Reverse Phase
Now, the summed response in Fig 2 (Red trace) developed a notch on the left of the crossover frequency.
This indicates the acoustic offset is playing havoc with the crossover.
With the RX14 still wired in reverse phase, delay ia added to the RS180S until a deep notch is observed (Red trace in Fig 3).
This is an indication that the acoustic centers of the RS180S and the RX14 are time aligned.
|Time Aligned Crossover
The Red trace in Fig 4 is with the RX14 wired back to normal phase. The response with the two drivers time aligned results in a proper summing.
|For clarity, the time aligned response (Red trace) is shown without the RS180S and the RX14.
It is now obvious that the RX14 has the flattest response of all four compression drivers tested.
The most notable difference with the RX14 is the smoothness in the music. There’s an absence of “grain” and the sibilance in voices doesn’t “spit” at you.
I deliberately left the high frequency attenuation unattended for the time being. It rolls of linearly from 5kHz upwards. Nothing too serious that some simple EQ cannot restore if desired.
Of all the compression drivers tested so far, the RX14 is beyond a doubt, the best. I can listen to it the whole day while working.