ULS-15 volume settings

[rbpeirce]

Yes, I could test this to figure it out for myself but I am hoping somebody has already done it. The volume control has markings and it is suggested to start at 11 o'clock. That's actually pretty good, but I am wondering how many dbs there are between each marking. For example, if I wanted to raise the output by, say, 6db, how far would I have to advance the control? Alternately, how much would I increase the output if I advanced the control by one mark?

I don't know if there is a difference between Mk 1 & 2. If so, what is the difference? I'm not sure which I have and I'm not at home.

[Kevin_Hsu]

Eh it really depends. 9-10 o'clock is what I would usually recommend with the ULS-15 original. The ULS-15 MK2 is slightly less sensitive. The potentiometer is not really linear, so I can't say that adjusting it a certain way will gain you a fixed dB amount. Really the only way to accurately know is by using a sound level meter.

[rbpeirce]

Hope springs eternal. Guess I'll have to work it out for myself. I have a room null near 30Hz and I should probably lower everything else rather than try to push it up. I've managed to even everything out above 40Hz (+/-2.5db) but the 30Hz dip is still there. Pushing everything above 40Hz down a couple db could be just about perfect. I'll try it when I get home.

[Kevin_Hsu]

Do you have a diagram of your room layout, by any chance? Are you running just one sub?

[rbpeirce]

I'm using two subs in the front corners. The room is 15X9 at the fromt end, 16x10 at the far end and 25.5' long.

[Kevin_Hsu]

When you say front end, are you talking about in front of the seating position? Not quite picturing that room clearly.

[rbpeirce]

The front is where the speakers are. That end is 9hx15w

The rear is 10hx16w. I built the room so it would expand and, I hoped, reduce the effect of room peaks and nodes.

The front and back walls are parallel and about 25' apart.

The crossover is 80Hz.

I get a peak around 20Hz and 45Hz and a really deep dip around 30Hz. These are all room modes. I also get a very high peak around 200Hz. I have no idea where that comes from.

I got everything pretty smoothed out with FabFilter. I was trying to figure out what to do about the 30Hz dip. One idea was to raise the entire bass range. I decided that might be more trouble than it is worth.

[ATL]

Your front and back walls may be to blame.

Two parallel walls exactly 25' apart will produce a mode at 22.6 Hz, 45.2 Hz, etc...

1130/2L = First Mode

1130 = speed of sound (ft per sec)
L = distance (ft) between walls

So: 1130 divided by (2 x 25') = 22.6 Hz.

I'm sure this also explains peaks farther up the spectrum like the 200 Hz you mentioned.