Tremendous dissatisfaction with the limitations of the previous test setup
being restricted to 2 meter measurements due to intruding room reflections
led to re-thinking of the situation. There is a long diagonal in my
livingroom, from the front door to the doorway leading into a hallway. Rudi
Blondia had previously mentioned the tradeoffs between an 'open door'
policy in measuring, and the increase of interferring outdoor noise
that might ensue.
Taking that risk of intruding noise and placing both the microphone and baffle on a line drawn through the door openings obtained approximately 7mS impulse measurements at distances of 1 meter, 2 meters, 3 meters and 3.5 meters without serious room reflections.
The 7mS data samples provide the same lower frequency limit of about 135Hz as the previous 2m measurements. There is a very significant difference in the measurements though, in this case the backwave of the dipole is both absorbed by acoustic foam (to a height of 54 inches from the floor); and, the backwave is further eliminated from the measurement by dissipation the the hallway complex.
This results in visible changes to the frequency response of the '3&SQ'
baffles compared to the earlier situation where the backwave of the dipole
was reflected from a wall. The following section details those changes.
Table of Contents - Two-Sided Baffles.
Comparison: Old & New Test Setup.
Listening Room Measurements Menu.
Table of Contents - Main Menu.
