# Do I need equalization with this frequency response?

Discussion in 'Speakers' started by GregBe, Sep 30, 2005.

1. ### GregBe Second Unit

Joined:
Jul 9, 2003
Messages:
277
0
I am not sure how to add my graph here, so I will post my numbers that are the compensated spl's. If someone can tell me how to post the graph, I would be happy to do so.

20hz = 68.2spl
22.5hz= 69.4spl
25 = 74.4
27.5 = 74.7
30 = 76.4
35 = 71.5
40 = 72
45 = 72.7
50 = 69.3
55 = 63
60 = 64.9
65 = 74.8
70 = 73.7
75 = 71.5
80 = 71
90 = 70.4
100 = 70.3
110 = 62.25
125 = 56.2
140 = 62.5
160 = 60
200 = 62

When you look at the graph, it looks great form 110 down through 65. It also looks real good from 50 down through 25. I don't see any real peaks. It looks like there is a dip from 50 to 65. Is this something to worry about?

Thanks
Greg

2. ### Brian Fellmeth Supporting Actor

Joined:
Jul 30, 2000
Messages:
792
0
Your way better off than most. I would be satisfied with that for movies. Bassy music would benefit slightly by flatening that out.

I assume these are pure sine waves ? Warbles will make the curve look better than it is.

3. ### gene c Producer

Joined:
Aug 5, 2003
Messages:
5,842
47
Location:
Bay area, Ca
Real Name:
Gene
What did you use to come up with these numbers? I'd love to plot my own.

4. ### FeisalK Screenwriter

Joined:
May 1, 2003
Messages:
1,245
0
Greg, check out http://www.photobucket.com/ to host your pictures, and you can use the [ I M G ] tag for referencing here

Gene, you can do you own with a SPL meter (radioshack, about \$40) and some test tones burnt onto a CD.

There's a guide on how to do this on Sonnie Parker's excellent BFD guide about a quarter way down the page (MEASURING SUB SPL LEVELS & USING MICROSOFT EXCEL WORKBOOK). You can download test tones and the excel workbook from there.

Once you have a graph, you might find some peaks (boomy) and dips (loss of sound) in your frequency response, and if there are, you'll WANT to fix it.

5. ### gene c Producer

Joined:
Aug 5, 2003
Messages:
5,842
47
Location:
Bay area, Ca
Real Name:
Gene
Thanks Feisal. My list of things to do on a rainy day just keeps on getting longer and longer!

6. ### FeisalK Screenwriter

Joined:
May 1, 2003
Messages:
1,245
0
haha, mine too but i won't wish a rainy day on anyone

7. ### GregBe Second Unit

Joined:
Jul 9, 2003
Messages:
277
0

Yes those are pure sine waves I downloaded from the ACI site. I have a one band equalizer on my sub that I can increase the spl at 20 and 22.5 hz to get it really flat from 35 down to 20. The only problem is I lose about 3dB of headroom. I am now trying to figure out if the additional response down low is worth that loss.

8. ### Sonnie Parker Second Unit

Joined:
Dec 11, 2001
Messages:
407
0
If you guys need your graph hosted, let me know. I'll host it on the BFD Guide and you can use that URL for your image link anywhere you like. I'm lookin' for graphs to place on the page anyway.

Just shoot me an e-mail.

9. ### John Garcia Executive Producer

Joined:
Jun 24, 1999
Messages:
11,576
24
Location:
NorCal
Real Name:
John
Hey Greg, that's about as good as one could hope for without equalization. Lucky guy...

Joined:
Dec 11, 2001
Messages:
407