The deep notch seen in the frequency responses for both the Carver and BG drivers, the Carver at ~2700-2800Hz and the BG at ~3600-3700Hz, are a result of the mounting method. The drivers were attached to two vertical 2x4 pieces of lumber on the 2" faces of the lumber. The resulting cavity formed by the lumber behind the drivers caused the notch. The spacing of the lumber was wider for the Carver!
The overlayed plot below contains the 1/12 octave smoothed frequency response plots of the unbaffled drivers (excepting the baffle created by the mounting method). It also contains the frequency response of the BG driver with it's notch filter in use.
Both drivers are seen to have large amplitude cavity resonances occurring through the range 3500 - 10000Hz. Use of the notch filter with the RD75 driver is seen to produce large effects upon the frequency response of the driver. The changes in the low-frequency response of the RD75 with notch filter installed were/are unexpected.
Below are shown the impulse responses of the drivers and the FFT derived frequency responses. These responses are UNSMOOTHED and are exceptionally clean! The complete data set of the impulse response from which the frequency response is derived is also shown. Note the complete lack of reflections in the data.
Microphone at 1 meter distance
Microphone height: 1 meter for RD75s; 1.21 meter for Carver 60s
MLS: 8 averages, 432/4096 point FFT, Half-Bingham window.
NO octave smoothing - Amplitude Axis @ 6dB per division.
| NO BAFFLE | Impulse Response | YOU ARE HERE | Waterfall FR |
|---|---|---|---|
| BAFFLED | Impulse Response | Frequency Response | Waterfall FR |
| OTHER | Calibration |
