JBL HM17-25
Manufacturers Info
Brand: JBL/Selenium
Model: HM17-25
Style: Bi-Radial
Coverage (H x V): 60 x 40
Minimum Frequency: 1,500Hz
Throat: 1"
Mounting Type: 1-3/8"-18 TPI
Dimensions: 6.34" W x 5.16" H x 4.16" D
Subjective notes on build quality:
Decent looking waveguide if you don't mind the protruding lobes of the bi-radial design. Overall fit and finish is excellent for it's low cost. Plastic is fairly thin but is not cheap feeling, it's a softer plastic which makes it well damped as it does not ring or resonate if knocked upon.
Measurements:
Test Notes: Off axis and polars measured using a Blast King 72BHM200PL compression driver. Off axis measurements are smoothed to 1/48 Octave.
Horizontal:
Vertical:
Raw horizontal off axis response
Raw vertical off axis response
Horizontal off axis response - normalized to on axis
Vertical response - normalized to on axis
Horizontal Polar Response - Normalized to On Axis
-6dB Coverage Angle Highlighted
Vertical Polar Response - Normalized to On Axis
-6dB Coverage Angle Highlighted
Notes:
Both the horizontal and vertical coverage is well controlled down to nearly 2 kHz. Both axis exhibit some narrowing of the pattern as frequencies rise but the off axis response is very smooth and matches on axis well, no major deviations for either vertical or horizontal. I'd say the coverage I'm seeing from these measurements put the dispersion closer to 80-90 degrees horizontal and 60-70 degrees vertical depending on where you choose to pick the coverage angle. Much wider then the rated 60 x 40.
On axis frequency response & distortion from tested compression drivers:
On axis - measured at 1m (scaled to 2.83v), no smoothing, 4ms gate: