[ted01]

OK, after staying up WAY too late last nite, I think I understand what I'm doing, a little. Here's my question: I'm looking at the suggested corrections in the EQ filters dialog box and I'm trying to figure out how to enter the correct settings into my DEQ2496. In the 2496, I have selected the PEQ configuration menu. The EQ filters info in REW says I need a filter with a center freq of 130.2, a gain of -18dB, and a BW/60 of 2. The part I'm confused about is the BW/60 part. The 2496 has a setting (Q?) for BW/Oct. It is scaled from 1/10 to 10. If the EQ filter wants a BW/60 of 2, what does that translate to on the 2496 (BW/Oct)? I got the center freq and gain thing under control, it's just this one setting I'm having trouble understanding.

Thanks a million,
Ted

 

[JohnM]

It would be easier to select FBQ2496 as the equaliser type rather than DSP1124. DSP1124 specifies bandwidths in 1/60ths of an octave, so the 2 means 2/60 = 1/30th octave. FBQ2406 uses octaves directly. Note, however, that there are inconsistencies between models. The DSP1124P figures are half those of the FBQ2406, for example (15/60ths on the DSP1124P is the same as 0.5 on the FBQ). Your DEQ is probably like the FBQ, but to be certain you could set up a filter on your DEQ and just measure the DEQ alone to see what REW settings the shape matches.

 

[mda185]

You can calculate the value of Q with the information you provided. Q is defined as CF/BW. Your CF is 130 Hz. Your BW is 120. Q is equal to 130/120 = 1.08. 1.08 is the value to enter in the DEQ software for this filter.

I just reread the other posts and now, I see I probably made a mistake. The DEQ2496 is not asking for Q, is it? I need to go back and read the manuals for REW and DEQ to try to answer this. I am interested in the answer because I just purchased and DCX2496. Still waiting for mine to arrive. I assume filter setting process is similar.

 

[JohnM]

There is more info on bandwidth and Q settings for the equalisers REW emulates in the help files, online here. Definitions of Q and bandwidth depend on whether the device specifies bandwidth in octaves or Hz and whether at the half gain points or the -3dB points.

 

[Drudge]

Here is a link to a Q to bandwidth chart that I use for the DEQ.
http://www.sengpielaudio.com/calculator-bandwidth.htm

If you scroll to the bottom of the page their is a chart with the conversions.You would set the EQ setting in REW to generic and then it will give the decimal value for Q.Then look at the chart and you'll find the bandwidth match for the decimal value in the column next to it.:T

You will notice with REW doing its auto filter suggestions that a lot of the times you won't find and exact match with the DEQ(both in frequency and bandwidth)so you will have to manually try to match as close as you can with what the DEQ has available.

I just manually input my own filters. It takes some time but you usually can get pretty close to what you need if not I find it better to just not bother with it.


Also beware that the DEQ doesn't have filters for everything listed on the chart their are gaps in its filter choices and it has a few that aren't listed on the chart as well.

Anyway, the chart should make things easier that having to manually calculate Q to bandwidth.:bigsmile: