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Problems Setting Filters on BFD.


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6 replies to this topic

#1 of 7 OFFLINE   Nelson T

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Posted March 30 2002 - 03:46 PM

I can not seem to program more than 2 filters on my BFD. Once I have programmed the first 2 filters and try to set the 3rd, there seems to be no effect or change in my readings. I have read the owners manual and Sonnie's BFD Setup Guide carefully, so I am not sure what I am doing wrong.Posted Image

Here are my BFD readings

As you can see my first filter is at 28Hz and my second one at 31.5Hz. I have also tried other frequencies on the first 2 filters and they seem to work fine. So I know that I have dialed on to the correct frequency for the other filters that I tried to setup that seem to have no effect.

Nelson

#2 of 7 OFFLINE   Rick Radford

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Posted March 30 2002 - 04:32 PM

Nelson,

Are you saying that any other filter you set has no effect? If I understand you correctly, I'm wondering about your basic setup of the BFD... ie, are you sure you're changing filters within a single preset? Or might you be changing presets? It can be confusing.. and your results tend to make me think you're changing presets when you think you're selecting another filter.

Make sure you have one preset selected (preset 4 or 5 would be good because they are already set up as parametric). Let's say you use preset #4. Next press the filter select button (turns the LED on). Now you can select filters 1-12 from preset 4 by rotating the jog wheel. Adjust the parameters of each filter as you see fit.

Remember that if the Filter Select LED is off, you are looking at presets.. not filters in the BFD's display. Also, the number of red LED segments illuminated tell you how many filters are active for the preset you've chosen.

For starters, your BW is very narrow.. 1/60 octave. Are you taking all the measurements manually?

I think I'd start at 36Hz, and try a 15/60 or 20/60 BW, -12 to -15 dB or so to start and then see what your response is before trying the next filter.

Note: my BW calcs suck. Posted Image .. so consider the above as a WAG.

What I found works best for me is to run the ETF5 software and watch the effect onscreen as I adjust the filter parameters on the BFD.. in which case we don't need no stinkin' BW calculations. Posted Image

Also, make sure you have sufficient input levels going into the BFD. (the red clip light should just illuminate occasionally at your maximum listening level).

brucek and Wayne P. have numerous posts around here that deal with BFD and EQ'ing... much of it since the first of this year.. so it should be current info.

HTH.
--RR

#3 of 7 OFFLINE   Nelson T

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Posted March 30 2002 - 04:55 PM

Rick,

Thanks for the quick reply!

It seems that once I set my first two filters in preset 4 that the 3rd one I try to set up has no effect. I am changing my filters within the same preset (Preset 4).

Yes, I have taken all my measurements manually.

Quote:
I think I'd start at 36Hz, and try a 15/60 or 20/60 BW, -12 to -15 dB or so to start and then see what your response is before trying the next filter.

I will give this a try tonight...

Quote:
Also, make sure you have sufficient input levels going into the BFD. (the red clip light should just illuminate occasionally at your maximum listening level).


How would this have an effect on my readings?

Also, I have done a search on the forum, but I could not find anything relating to this particular problem with the BFD.

Nelson

#4 of 7 OFFLINE   BruZZi

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Posted March 30 2002 - 06:31 PM

Why don't you try using a different preset like # 5 for example,and see if that works.





#5 of 7 OFFLINE   Rick Radford

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Posted March 30 2002 - 11:01 PM

>How would this have an effect on my readings?<

W/r/t input levels, it shouldn't. But was just a general setup consideration.

Hmm. Sounds like you're familiar with the difference between presets and filters... which leaves me puzzled about your problem.

Your web page only shows 2 filters. They both have too narrow of a BW as I mentioned earlier. You have the BW listed as 1.. which equates to 1/60 octave. The range of the BFD is 1/60 to 120/60 (2 octaves).

At 28 Hz (for example), a 10/60 (1/6 octave) BW would have outer parameters (o.p.) of 25 and 31.5 Hz. So you can imagine what a 1/60 octave filter would do (not much).

Here are some examples that Wayne P posted in another thread:

1/6-octave, 22Hz, -5dB. The o.p. frequencies are 20Hz and 25Hz.
1/3-octave, 32Hz, -9dB. The o.p. frequencies are 25Hz and 40Hz.
1/3-octave, 50Hz, +8dB. The o.p. frequencies are 40Hz and 63Hz.

HTH.
--RR

#6 of 7 OFFLINE   Tom_A

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Posted March 31 2002 - 01:43 AM

Nelson - I had the same thing happen when I first tried to use the BFD. Turned out I was setting the frequency incorrectly. Make sure when you dial in the frequency there is not a decimal point in front of the number (for example, if you were dialing for 50Hz it should look like "50" on the display not".50"). Also, the small indicator light to the right of the right of the display should read "Hz" and not "kHz". It was driving me crazy why I would not get any change in readings until I realized that I was setting a filter for 500Hz when I wanted one at 50Hz!

#7 of 7 OFFLINE   Nelson T

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Posted March 31 2002 - 05:27 AM

Quote:
Make sure when you dial in the frequency there is not a decimal point in front of the number (for example, if you were dialing for 50Hz it should look like "50" on the display not".50"). Also, the small indicator light to the right of the right of the display should read "Hz" and not "kHz".


Tom - That was exactly what I was doing wrong. The BFD sits close to the bottom of my rack that I did not pay close enough attention to the "." :b

Quote:
think I'd start at 36Hz, and try a 15/60 or 20/60 BW, -12 to -15 dB or so to start and then see what your response is before trying the next filter.


Rick - I have tried your suggestion... yielding much better results. Thanks

Thanks to everyone else who replied to this post. Posted Image


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