|Dayton Audio H07E
The HE07E is a compact 6″x6″ Elliptical Waveguide with a coverage of 80° (H) x 50° (V).
Minimum Crossover is 2,200Hz.
Standard screw mount 1-3/8″ x 18 TPI.
Made of ABS plastic.
|PRV Audio D280Ti-S
The D280Ti is a 1″ exit Compression Driver.
Diaphragm is made of titanium.
Frequency Response is 1,300Hz ~ 20,000Hz
Minimum Crossover is 1,800Hz (12dB/oct)
Standard screw mount 1-3/8″ x 18 TPI
|Frequency Response of D280Ti with H07E
Black trace is at 1,600Hz (6dB/oct).
From these plots, we can see the D280Ti and the H07E are quite a good match. Response from 3kHz to 8kHz is generally flat. After that, it rolls of linearly at about 6dB/oct. A simple CD EQ will be able to lift the higher frequencies if desired.
|Crossing Dayton RS-180S with PRV D280Ti
From Fig 1, it appears I can cross at 2,000Hz but since the H07E minimum crossover is recommended at 2,200Hz, I decided to cross at 2,500Hz. Both High Pass and Low Pass are at 24dB/oct. Crossover is with Pioneer FH-X731BT.
|Time Alignment with Pioneer FH-X731BT
The Black trace in Fig 3 is with the D280Ti in reversed polarity. The notch centers at 2kHz. This is due to the acoustic centers of the RS180 and the D280 are out of alignment.
The Blue trace is when the RS180 is delayed by 1 inch. Now, the notch has shifted closer to 2.5kHz.
|Result of Time Alignment (D280Ti wired In-Phase)
Without time alignment (Black trace), we can see there are some cancellation in the summation, resulting in the depression around 3kHz.When properly time aligned (Blue trace), there’s no cancellation, hence no depression.
|Time Aligned Frequency Response
Fig 5 shows the full spectrum response of the RS180S and the D280Ti with the H07E waveguide. Disregard measurement below 500Hz. My room is interfering with the reading.
I am surprised to see the RS180S bass response (55Hz to 100Hz) is almost at the same volume as the midrange. Usually, it’s about 3dB less.
The RS180s is loaded onto a 19 liters, bass reflex box, tuned to an F3 of 45Hz. The deep notch at about 150Hz is caused by floor bounce. Nothing to be concerned about.
I’m sure most would ask “How does the PRV D280Ti sound like?”. Frankly, pretty good. Can’t find any fault. I’m certain that even when crossed at 2kHz, the D280Ti will not present any problems.
When used together with the RS180S, the speaker sounds excellent. Contrary to popular believe that a metal cone midwoofer with a titanium compression driver is a recipe for harshness, this speaker debunks that myth. There’s no harshness whatsoever. No compression driver “honk”. Just sweet treble.
The PRV D280Ti and Dayton H07E combo is pretty impressive. Even though compression drivers are mainly used in pro systems, this combo is refined enough for hi-fi.
October 21, 2016PRO DRIVERS