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Ok, every time I created a set of filters, I all the sudden got a very big dip in my graphs at about 30 to 40 hz
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If by this you mean that the second graph shows the response dropping away at 30 to 40Hz, I see what you mean.
This is certainly not normal for a BFD and you either have some filter set or you have a fault on the unit. They simply don't do what your graph shows. The IN/OUT simply shuts off the filters section in the DSP. It isn't a hard bypass as you might expect.
If you want to do the response check of your BFD, you can use REW to accomplish that. It might be worthwhile in your case.
Here's how.
When you calibrate the soundcard, you have a cable from line-in to line-out on your soundcard. After you've completed that calibration, leave the cable in place and do a response measurement of the cable itself (this shows that the soundcard cal file is working). You should get a perfect flat response.
Now insert the BFD into that cable and do a response check. (obviously you'll need two cables). The measurement will show the response of the BFD in the loop. (Be sure to have the meter cal file clear so it isn't added into the mix).
Now you can play with the IN/OUT switch and do some response checks of the unit itself and really see what the story is...
By the way, when you use REW for measuring a sub, set the Graph axis of the vertical from 45dB to 105dB (using the Graph Axis icon in REW. Also best to set the horizontal axis from about 10Hz to 200Hz.
When you measure a device, such as the BFD, you can exaggerate the vertical axis to something like 70dB to 85dB, so you can really see the small response differences.
Here's a response graph of my 1100P with the IN/OUT switch in and then out. I had to separate the two graphs, because if I didn't, you wouldn't know there were two. That's how close the response is between IN and OUT...... See how low the BFD goes in its response - all the way to 2Hz and that's with a fairly exaggerated vertical scale. The 1100P actually has a better response than the 1124P.....
bfd 1100p in and out.jpg
brucek
brucek