Axiom Home Page Forums General Discussion Home Theater BFD & 600s All Set Up

Hi everyone!

Been lurking for a long time.....great forum.

I have a question for all you BFD tuners here. First let me give you some corrected SPL numbers:

Rat Shack meter, C-weighted, slow response:

18hz @ 68db
20hz @ 71.5db
23hz @ 80.5db
26hz @ 87db
29hz @ 95db
32hz @ 98db
36hz @ 102.5db
39hz @ 102.5db
42hz @ 100db
45hz @ 98db
51hz @ 97.5db
57hz @ 102.5db
63hz @ 98db
72hz @ 95.5db
78hz @ 92.5db
84hz @ 93.5db
90hz @ 98.5db
102hz @ 87db
114hz @ 84.5db
126hz @ 90.5
132hz @ 89.5db
138hz @ 89.5db

Sub is a psb subsonic 3, 12" driver w/180w amp.

X-over on sub is dialed to it's 150hz max.

Receiver's X-over is at 80hz(12db/octave high pass, 24db/octave low pass).

I currently have a BFD running bypassed, and am wondering if I should even use it, and if so, what should I focus on?

Thanks for any opinions!

No, you shouldn't use it. I'll give you an address you can ship it to... I'll just take care of that for you.

Good one Ken, you beat me and a few others to it I think.

Why I oughtta.....!

Whatch it, or I'll get Ajax on you!!

I had some time to kill, so here's a chart of your response:



Here's the Excel spreadsheet file, as well.

May I assume that your target reference db was 95? If so, then I'd start your tweaking with 3 filter points:

One at 40Hz, with a bandwidth of 1/4 octave, and a cut of 6dB
One at 57Hz, with a bandwidth of 1/8 cotave, and a cut of 8dB
One at 80dB, with a bandwidth of 1/8 octave, and a boost of 3dB

These are very rough estimates, but they should result in a flatter response.

Wow! Looks like the spreadsheet I did! Thanks pmbuko, I am going to try those filters out. Actually, I set the meter to read 74db at 23hz(uncorrected), but the 95db level will work. The sub really drops below 30hz like a rock.....surprised me.

Lovely graph.
Time to kill?
You know i have these groceries that have been on my list for about a week along with a garden to clean out...

What can I say, I'm over 1000 miles away from my chores...

**think Proclaimers**

NOW I WOULD WALK 500 MILES, AND I WOULD WALK 500 MORE.
JUST TO BE THE MAN WHO WALKED 1000 MILES, TO FALL DOWN AT YOUR DOOR!



hey, i got plenty of stuff for you to do, and i am only about 240 miles away...

bigjohn

I like NOFX's lyrical response to the Proclaimers in "Whatever Didi Wants":

I wouldn't walk 500 miles when I could fly coach but almost anything
I wouldn't swim across the Nile cause I could get amoebic dysentery

'Cause if there's anything you want
I'll probably get it
you tell me what you need
I'll try not to forget it
you need someone to blame
I'll say I said it
Whatever Didi wants
She's gonna get it

I wouldn't climb the highest mountain could get a blister, but almost anything
I wouldn't throw coins in a fountain I might be needing to make a phone call

It doesn't seem like you're a million miles away, no... but maybe one or two
That doesn't mean, I never loved you. Me love you long time... when you're on top of me

Now that's my idea of a punk love song.

Bren R.