IMPULSE RESPONSE COMPARISION: Without Baffles.

Comparative inspection of the impulse responses of drivers, made under similar conditions, can reveal much about differences between the drivers. It is a fact that, mathematically, impulse and frequency responses are two different views of the same event - one is a time-based and the other a frequency-based view of the same data. This is the essence of the Fourier Transform, time and frequency are convertable with proper mathematical tools.

The first two comparisons shown also contain impulse responses from the 'With Baffles' condition.

Below is the plot of the complete 4096 point data sets of the acquired impulse responses (without notch filters) of both of the Carver and BG planar drivers. Note the major reflections in the data appearing past the midway point on the plots. The thickened 'Green' trace impulse spike is apparently an artifact of the plotting. Expanded views are shown below.

Damaging evidence, in regards the question of driver damping, is already seen in this display. Note that the impulse 'tail' on both Carver drivers extends well past the end of the impulse tail on the BG drivers.

Below is shown the 432 point data domains from each of the four drivers, without notch filters installed, that were used in the frequency response analysis portion of this comparison.

With both Carver drivers, under both conditions, with and without baffles, low-level 'ringing' in the impulse responses is seen to the midway point in the data set. Both BG drivers seem to have an end to their impulse tails in about 1/2 the time of the Carvers! An "underdamped" driver continues to 'ring' longer than a better damped driver.

Below is shown a 50 point data domain for each of unbaffled driver conditions. For the first time it is seen that the driving impulse is attempting to simulate a rectangular pulse. Clearly it has finite risetime and a small, but measurable undershoot on the return to zero amplitude.

Both the Carver and BG drivers show good correspondence in the shape of the impulse signal. The 'tail' of the impulse response of the Carver driver shows greater amplitude excursions for a longer duration than does the BG driver.

Note that with the use of the notch filter with the RD75 driver there is a large reduction in the ringing of the impulse tail; and, the top of the impulse response changes directions to match that of the driving impulse.

Below is shown a 25 point data domain for both drivers (no notch filter) and the driving impulse. It is provided in order to show very high resolution detail of the impulse responses.


Sampling Rate: 61200Hz - Point resolution = 0.000016S
Microphone at 1 meter distance
Microphone height: 1 meter for RD75s; 1.21 meter for Carver 60s

CARVER60 vs RD75 UNDERDAMPING COMPARISON

NO BAFFLE YOU ARE HERE Frequency Response Waterfall FR
BAFFLED Impulse Response Frequency Response Waterfall FR
OTHER Calibration

The RD75 Dipole Baffle Study - Table of Contents.
Acoustic Line Source Research - Table of Contents.