Testing Method Ideas

[Jimmy9]

Measure the Nulls and Dips Directly.

I was trying to determine; if I can only afford one (or two) bass traps or a limp membrane trap, where will I put it. Then i thought, maybe this would be useful for anyone thinking about listening position and speaker placement. Especially if you’re trying to make sense of REW measurements and your room and the endless convo about bass accumulation.

This is what i did;

• Set the REW generator to play a specific sine wave that corresponds to a big low freq null in your REW SPL result. (mine was 77hz)
• I played it around 70db.
• Walk around the listening space and listened. I could feel and hear the varying pressures in the room. I could feel and hear what i saw on the SPL result.
• I then used SPL meter. iPhone Decibel or SPL meter app is good enough for this. (I checked against my UMIK, they are very close)
• Measuring the corners of my room. Just like in the REW graph a drop that very clearly corresponds to what you can hear.
• It also gives you a really tactile feel for SPL. You actually feel the uneven pressure it has created in the room.

Is there any reason wouldn't use something like this when guiding us REW noobs?

 

[Matthew J Poes]

Measure the Nulls and Dips Directly.

I was trying to determine; if I can only afford one (or two) bass traps or a limp membrane trap, where will I put it. Then i thought, maybe this would be useful for anyone thinking about listening position and speaker placement. Especially if you’re trying to make sense of REW measurements and your room and the endless convo about bass accumulation.

This is what i did;

• Set the REW generator to play a specific sine wave that corresponds to a big low freq null in your REW SPL result. (mine was 77hz)
• I played it around 70db.
• Walk around the listening space and listened. I could feel and hear the varying pressures in the room. I could feel and hear what i saw on the SPL result.
• I then used SPL meter. iPhone Decibel or SPL meter app is good enough for this. (I checked against my UMIK, they are very close)
• Measuring the corners of my room. Just like in the REW graph a drop that very clearly corresponds to what you can hear.
• It also gives you a really tactile feel for SPL. You actually feel the uneven pressure it has created in the room.

Is there any reason wouldn't use something like this when guiding us REW noobs?

That approach is very common. Pros do the same thing. You can also take actual sweeps in those spots. A lot of pros do exactly as you did.

Another trick is to place a sub in the middle of the room and walk around. Then move the sub to a spot with a more even response. Walk around again. Keep moving the sub around and testing again. It’s a common trick used to find optimal sub locations. It works well if using a single sub, but with multiple LF sources it isn’t necessary (and so not an approach I use).

Good job!