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BFD Settings Recommendation


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#1 of 33 Chris Huber

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Posted September 01 2005 - 12:20 AM

Hey guys, I just got my BFD in last night and set it up. I ran through the setup on http://www.snapbug.ws/bfd and am no familiar with all the settings I need to make...

My graph is here: (blue line is what need to fix, ignore red line)
Posted Image

Can you guys please make some recommended filter settings I need to change?

_______________
IE:
Peak 1 = ?-?hz
FREQUENCY of middle of peak =
BANDWIDTH for peak coverage =
GAIN =
_______________

The above chart filled out for all my peaks would be wonderful if you could take the time to do it... I realize, it may be estimates and I might need to tweak, but it would give me an understanding of what needs to happen.

Also, can someone explain the BANDWIDTH setting? I don't really understand that. I know it coverage on either side of the peak Hz number, but don't know how to measure it...

Thanks for all your help in advance...

#2 of 33 BrianWoerndle

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Posted September 01 2005 - 01:10 AM

You can't really do everything at once. After you make a change, you need to re-graph and see how it affected everything else.

I would start with a cut at 40hz, -10db, 6-8 bandwidth.
You will then probably need another cut in the 50's.

You can try a cut at 82, but I had trouble getting rid of the higher bumps because of the interaction of my room and mains.

You can see by my graph that it can be hard to get every peak tamed. But mine is pretty flat in the lower bass down to 14hz.

You have a pretty nice graph there. What sub are you using? It is solid down to 20hz.
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#3 of 33 PaulT

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Posted September 01 2005 - 01:26 AM

Chris,

I have found this spreadsheet to be invaluable for BFD setup. It can show you what various changes in frequency, gain and bandwith will do (theoretically Posted Image of course, ignoring room issues) to the values for the curve you enter.

http://www.pvconsult...udio/eq/peq.htm

Use it in conjunction with the one you have gotten from the snapbug site. There is a reasonable bandwidth explanation on snapbug as well - you have the basics of it - a value plus/minus from the centre frequency. The link to Wayne's post near the bottom of the snapbug site is great so I'll relink it here:
http://www.hometheat....407#post708407

Bandwidth in the BFD is in /60th of an octave, so 30/60th is one half an octave (doubling or halving of the frequncy is an octave, eg. it is one octave between 20Hz and 40Hz, but it is also one octave between 40Hz and 80 Hz - due to the logarithmic scale).

Based on your graph, start with the peak around 40Hz. Try cutting it 5 or 6 dB and experiment on the bandwidth setting in the PEQ spreadsheet.

The dip you have around 68Hz is probably due to the room (a null). Moving the sub around should shift the frequency and/or reduce (or increase) the amount of dip but I would not try to boost too much (more than 4 or 5 dB) around that frequency as you probably will not have too much luck.

It can be frustrating at first, but you'll get the hang of it. Measure, make changes, remeasure. Keep the significant other away from the house for a few hours and keep the tones fairly short.

Good Luck
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#4 of 33 Chris Huber

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Posted September 01 2005 - 02:16 AM

Quote:
You have a pretty nice graph there. What sub are you using? It is solid down to 20hz.


SVS 20-39PC+

#5 of 33 MikeyWeitz

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Posted September 01 2005 - 04:11 AM

Not too shabby of a sub :-)

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#6 of 33 Robert*S

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Posted September 01 2005 - 08:52 AM

Ah, the BFD. What a marvelously confusing peice of gear to use to e.q. a sub! Posted Image
I have a BFD in my system with an SVS 22-31PCi and it took me about 5 hours (and a lot of luck) to get a nice flat response. See link:
http://groups.msn.co....to&PhotoID=586

Read and re-read the snapbug guide and dive right in. It will start making sense after you make a few changes and measure again. Good luck and let us know how it goes!!

#7 of 33 Chris Huber

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Posted September 01 2005 - 10:27 AM

Well, I put some settings in filter 4 last night. Now I want to change those settings... When I select program 4, then filter 1. I can't change the frequency or the gain settings for some reason. When I move the jog wheel, no number change... Help me out here.

#8 of 33 Wayne A. Pflughaupt

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Posted September 01 2005 - 10:51 AM

Chris,

Your situation is going to be a little tricky, because most of your peaks and lows are asymmetrical – i.e., they are steeper on one side than the other.

For instance, take a look at the peak centered at about 82 Hz. To the left of the peak, it’s about 1/6-octave to where the peak bottoms out. If the line on the right continued down to the 70 dB line like it does on the left, it would be a 3/6- (half-) octave from the peak to that point.

EQ filters are symmetrical, so you can’t resolve asymmetrical problems with a single filter. It will take at least one extra filter to “clean up” what the first one can’t get to.

You will probably want to set your filter based on the narrow side of the dip or peak, not the broad side. That way your second “clean up” filter will be fixing what the first couldn’t. If you set your primary filter for the broad side of the peak or dip, you’re going to be digging a hole, as it were, on the narrow side where there wasn’t a problem before. Then the follow-up filter will be filling the hole you created with the first. Hope that makes sense. It’s probably just “six of one, half a dozen of the other” thing, but it just seems like a more sensible utilization of the equalizer to fix problems, not create new ones.

I’d recommend three filters for starters:
  • Brian’s 40 Hz filter @ -10 is a good start. I don’t know what the 6-8 bandwidth translates to in octaves (I keep hoping someone will tell me how Behringer’s proprietary bandwidth nomenclature translates to the octave or Q settings the rest of the world uses Posted Image ), but you’ll probably want it to be about 1/6-octave or perhaps a little wider. This will leave the little peak at 55 Hz looking much bigger than it is now – it’ll be another asymmetrical peak, so it’ll probably require a couple more filters to deal with.
  • 68 Hz, about 1/4-octave, boosted 6 dB. This one is symmetrical, so one filter should do it.
  • 82 Hz, 1/6-octave, cut 8 dB. I probably wouldn’t worry about a second filter for the high-side of this one, since it would end up being pretty near the crossover frequency.
Regards,
Wayne A. Pflughaupt

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#9 of 33 Chris Huber

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Posted September 01 2005 - 11:19 AM

Ok guys... I have got most of my new settings in place...

2 Issues:

1. On my last(6th) filter, the GAIN glows red and I can't change the setting with the jog wheel. Why is it locked?

2. On the RoomEQ program, what does the Q level mean on the BFD Bandwidth? If I have 10 for Q on roomeq, why do I set the BANDWIDTH value to on the BFD?

Thank you.

#10 of 33 Chris Huber

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Posted September 02 2005 - 05:08 AM

Bump

#11 of 33 Chris Huber

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Posted September 04 2005 - 08:12 AM

Alright guys. I figured out all of the problems from my previous post... The BFD guide said something about putting it in SI? So thats where i thought it needed to be... Long story short, it needs to be in PA mode...

I'll post a graph of what I have so far when i get home! I really flattened out some peaks...

Couple questions...

1. What did you guys do about the brightness of the front panel? I am thinking about cutting a piece of tint out and putting it over that. Also, the top red row, channel 1 lights are light solid on 1-4 (my 4 set filters. Is there a way to dark out the bottom red row to keep them from blinking red all the time? I was thinking enable channel 2, set all the gains to 0, so the lights will go off... I think they turn red only when gain is set + or -...

2. Up around 80+ Hz, my mains make that peak, so there is really nothing I can do about that? (have the JBL S 12 inch floor standings) I set a filter for 83 HZ, but nothing dropped...

3. What about the "pop" noise when you turn the amp off, then right back on again? It is noted in the snaplug site... It's really not a problem, unless I forget and turn the amp right back on. The pop is pretty loud!

#12 of 33 Max F

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Posted September 05 2005 - 03:36 AM

I keep everything on, the amp and the BFD. Just remember if you have to power back up, turn on the BFD then the Amp.

I also hide mine in the corner by the subwoofer. Once its set up you don't really need to fiddle with it anymore. So why look at it? I still can see the little lights in the corner when i stand up and look. I like to look at what kind of input my sub is getting every once in a while.

My bottom lights are off, BTW because i think i cleared all of the seetings for that channel. I believe that was recommended in the BFD guide site.

#13 of 33 Chris Huber

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Posted September 05 2005 - 10:48 AM

"I keep everything on, the amp and the BFD. Just remember if you have to power back up, turn on the BFD then the Amp."

I actually have the BFD plugged in to the reciever... So it does come on when the reciever is on. Guess there is no way around it...

#14 of 33 Max F

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Posted September 06 2005 - 01:15 AM

Don't plug it into the reciever. Pretty easy solution, actually.

#15 of 33 Chris Huber

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Posted September 06 2005 - 01:26 AM

Then you have to manually power on the BFD... Posted Image

#16 of 33 Chris Huber

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Posted September 06 2005 - 03:03 AM

Here are my latest corrections...

These are the filter used to achieve the below correction.
Filter Freq Gain B/W
1 (40)40+0 -30 10
2 (55)50+8 -8 3
3 (66)63+4 +6 10
4 (45)40+10 -10 5
5 (63)63+0 -2 2
6 (34)32+6 +2 4

There are is on with -30 in gain... I tried less, but just couldn't get it to target... So, thats where I left it... I know the +6dB boost on filter 3 is 3dB over the recommended boost, but should I be fine with that?



Before=Blue after=red
Posted Image

The above was fixed using 6 filters because my peaks where not uniform in shape(and maybe I am just a noob at setting filters.)

Now, I haven't tackled the peaks from 20-28hz. I do have a question about those though... Should I leave them maybe 5-10dBs over my 75 target? Those you should only feel more then hear, right? Should I leave it as is(gradual slop down to my target, or tame them down a bit?

The Peaks after 71Hz are not able to be tamed due to the big JBLS312II's I think... No matter what filter I set there, I can't take the dBs down.

#17 of 33 Wayne A. Pflughaupt

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Posted September 06 2005 - 01:53 PM

Quote:
The above was fixed using 6 filters because my peaks where not uniform in shape(and maybe I am just a noob at setting filters.)
That sounds about right, actually. Good job. Posted Image

Quote:
I know the +6dB boost on filter 3 is 3dB over the recommended boost, but should I be fine with that?
It looks like the 6 dB boost there was virtually eliminated by Filter #5. Try again. Posted Image

Quote:
Now, I haven't tackled the peaks from 20-28hz. I do have a question about those though... Should I leave them maybe 5-10dBs over my 75 target? Those you should only feel more then hear, right? Should I leave it as is(gradual slop down to my target, or tame them down a bit?
It will probably sound really “heavy.” Go ahead and flatten it along the 75 dB line, and then dial in a house curve to taste with an overlay filter. I believe that technique is mentioned in the BFD setup guide.

Quote:
The Peaks after 71Hz are not able to be tamed due to the big JBLS312II's I think... No matter what filter I set there, I can't take the dBs down.

The sub probably needs to be turned up, since equalizing has significantly reduced its overall gain.

Regards,
Wayne A. Pflughaupt

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#18 of 33 Chris Huber

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Posted September 07 2005 - 02:08 AM

Quote:
It looks like the 6 dB boost there was virtually eliminated by Filter #5. Try again.


So, maybe by eliminating filter 5, extending the B/W of filter 2 to maybe 5, it may work...

Quote:
The sub probably needs to be turned up, since equalizing has significantly reduced its overall gain.


I don't understand how turning up the sub(I may a little) will help with my 80-100 range peaks? If I set a filter now, and it doesn't change anything, that tells me that the mains are taking over...
Do these stats tell you canything about the mains freq response?
http://www.jbl.com/h....CheckProduct=Y

#19 of 33 Max F

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Posted September 07 2005 - 03:05 AM

Quote:
Then you have to manually power on the BFD...


Once you have it set up, leave it on, hide it, and fugitaboutit. Posted Image

#20 of 33 Max F

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Posted September 07 2005 - 03:07 AM

Quote:
I don't understand how turning up the sub(I may a little) will help with my 80-100 range peaks? If I set a filter now, and it doesn't change anything, that tells me that the mains are taking over...


If you turn up the sub, you will be close to the amplitude of the peak at 80hz... Good luck!


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