Current data has been acquired at heights of 0.75m, 1.0m and 1.25m, which might be considered to encompass the range of normal listening heights. Distance data was collected at one meter intervals to either 7m or 8m. Future data may only be collected to a 6m distance.
The frequency/phase plots are the result of merged responses, at approximately 600Hz, of full-range data collected at a 61KHz sampling rate and high-resolution low frequency data collected at a 1.9KHz sampling rate. No FFT 'windows' were used in the data analysis; and, the frequency data represents 1/12 octave smoothing.
There is NO active filter in circuit for these measurements, or any other equalization other than the required passive notch filter for the RD75 driver. Comparisions between this data and the 'Listening Room' data must take into account the fact that all 'Listening Room' data incorporates a 150Hz high pass active filter as part of the measurements.
Baffles noted with the label '(=A)' are part of an ongoing series of baffles that all have equal surface area. It is highly instructive to note the changes in response that occur with baffles having the same surface area but differing shapes. Simple 'average' width calculations of an RD75's baffle do not adequately describe the potential responses of the differing baffle shapes.
| Listening Distance Comparisons | 0.75m Height (35K) | 1.00m Height (35K) | 1.25m Height (35K) |
|---|---|---|---|
| 1S6T (=A) | 0.75m Height (78K) | 1.00m Height (78K) | 1.25m Height (78K) |
| 1S9T | 0.75m Height (78K) | 1.00m Height (78K) | 1.25m Height (78K) |
| 1STR (=A) | 0.75m Height (89K) | 1.00m Height (89K) | 1.25m Height (89K) |
The Gymnasium Measurements - Woofer Integration
The Auditorium Measurements - Introduction
The RD75 Dipole Baffle Study - Table
of Contents
Acoustic Line Source Research - Table of Contents.