[Bruce Fisher]

I apologize if this information is somewhere else... I've looked and read lots of information but haven't really seen these questions answered.

I used REW and adjusted/calibrated a BFD1124 to improve my subwoofer by eliminating 1 big and 1 modest peak. I have a good graph with a house curve that sounds very very good to me... I'm very pleased with the results and thank everyone that spent so much time putting this together and explaining and documenting and answering questions on the forum. :clap:

What I'm wondering is:
- how do I use REW to help me adjust the subwoofer phase? Do I simply take lots of graphs adjusting the phase 10-15 degrees each time and pick the one with the best curve? Or is there something else I should do?

- how do I use REW (waterfall graphs?) to determine how much more room treatments I need? Or where to put them? I read the waterfall thread but still don't know how to determine this.

- My speakers (Emotiva 6.3s) have toggles on the back for +/- 2 (or off) for midbass, treble, and has a boundary compensation switch. To use REW, do I just run several tests in various positions and look for the chart that's smoothest?

Many thanks!

 

[brucek]

how do I use REW to help me adjust the subwoofer phase?

You use the RTA feature of REW and adjust the phase while watching the dynamic graph move as you adjust.

Follow the info below on using the RTA:

To use the RTA feature of REW, you must first setup the levels as if you were about to make a standard response measurement.

This involves running the Check Levels routine for the mic at the listening position to 75dB and the Calibrate routine. You can even run a measure to have a reference.

Then, select the Spectrum tab in REW and setup the controls as shown in the picture below.

Then, select the REW Generator and select Pink PN and start the signal using the play button.

Press the Red record button on the Spectrum page.

You can monitor your Input Level on the Spectrum page in the bottom left hand corner.

If it reads clip at any time (if you're moving the mic around when using the RTA), then simply turn down the REW input level a bit.

Below shows a response measure I took (that gets transferred to the RTA graph), and the black line is the RTA itself. You can then adjust the phase control at this point while watching for the best response.

how do I use REW (waterfall graphs?) to determine how much more room treatments I need?

The waterfall will show how long a signal persists and rings out over the bandwidth chosen (usually 0-200Hz). Treatment isn't too useful below ~100Hz, but you would be looking to reduce the ringing as much as possible.

brucek

 

[Bruce Fisher]

great stuff - thanks for the info - I'll have to give it a shot this weekend.