I’m going to spend some time talking about working on low frequency response in room. I’m just learning this stuff, so feel free to point out information of note (references would be great, I’ll be picking up some books on the topic soon).
The room itself in in a fully finished basement with pad and carpet on concrete and 7.5′ ceilings. Here is a diagram of the room, click to enlarge (pink - speakers, purple - sub, green - treatments):
The numbers along the sofa are reference points for the measurements I’ll be posting later. Each time I do measurements, I measure at all six points for each test. It takes some time, but gives a much more complete picture of how things sound for various positions. The sofa back and mic stand are also marked to try and keep measurement positions consistent between runs. I also run a new baseline for each test and the baselines have remained consistent.
The room dimensions noted here aren’t exactly correct. I remeasured and the length is just under 22′. That would give an axial mode of about 25Hz (I tend to use this page for calculating modes - >http://www.marktaw.com/recording/Acoustics/RoomModeStandingWaveCalcu.html ). Since the main sofa is right about the half way point in the room, that places it in prime first axial mode location.
Since the room is open to another area and a staircase, it’s more difficult to predict behavior. My measurements show that the expected 25Hz mode is closer to 22Hz, but that’s for another post. I’m hoping to pick up CARA sometime and model the full space.
Measurements to come soon.
