Axiom Home Page Forums General Discussion Technical Questions Proper Sub Calibration

I was wondering if I could get other's opinions on proper sub calibration. As I understand it, the best way to properly calibrate a sub is this:

1) Get a DVD that will play frequencies in 1 Hz increments from 20/30 Hz to 100 Hz. Measure sub output using a RS SPL meter and plot a graph. This will show any dips/peaks in sub output

2) armed with the knowledge from the graph, attempt to manipulate the sub, room furnishings, etc to tame the peaks & valleys in sub output

3) when all avenues in 2) are exhausted, invest in a Behringer feedback destroyer to further flatten frequency response


Does this look right to everyone? Anything that should be done differently? Comments/questions?

If that looks like the best way to do things, where is the best/easiest place to track down a sub test disc (with 1Hz increments from 20Hz to 100Hz)? I've heard the name Rane bandied about before, would that be the ticket?

I'm perfectly happy with my system, but realize that I am not getting optimum performance from my sub. I just wanted to know what others' opinions are on how best to accomplish that.

thanks in advance

I have one called "Rives" . (Thanks Mike/mwc)
http://www.rivesaudio.com/software/TestCD.html
If you google "rives test cd" you'll also find some interesting reviews on this.

Sidvicious02,
If you want to down load the tones to your computer and make a CD disk. Go to (www.snapbug.ws/sinewaves) and down load the freqs that you want. That is what i did and it works great and you can't beat the price FREE.

thanks for the links guys

Koiman, that looks like a beaut, like you say, can't go wrong if it's free. I may try burning one tomorrow and see how it works. I've got the link for setting up a Behringer Feedback Destroyer. There's a speadsheet download that has the RS SPL Meter correction values already factored in. Should make it a breeze.

Bray, that's the one I was thinking of, not "Rane" - "Rives". The disc itself is very similar to what I was thinking of. Are the test tones at 1/3 octaves sufficient to tame frequency response???? Or should someone be more accurate with smaller increments????

thanks so far, keep the suggestions/comments coming!

I just used those mp3 sine waves. Ouch, I have a HUGE arc. At 25 Hz, things are pretty good. Then from 30 - 50 it climbs up about 20+ dB from centered (I chose 80 dB), then drops from 50 Hz - 130 Hz down to - 17dB from centered. Looks like I'm going to have to do some leg work with this sub.

Sidvicious,
If you have the excel spread sheet program on your computer the graph works perfect.

>> just used those mp3 sine waves. Ouch, I have a HUGE arc. At 25 Hz, things are pretty good. Then from 30 - 50 it climbs up about 20+ dB from centered (I chose 80 dB), then drops from 50 Hz - 130 Hz down to - 17dB from centered.

Yeah, welcome to the real world ;(

Sid,

This was copied and pasted from an earlier post of mine:

After owning my SVS 20-39 PC+ for almost six months now paired up with my M60's,VP150 and QS8's I have been so overwhelmed at it's performance I could never imagine it getting any better. Well let me be the first to admit I was wrong!

I just picked up a Behringer Feedback Destroyer from http://www.zzounds.com for $120 delivered to my door. After reading thru the setup guide at http://www.snapbug.ws/bfd.htm I hooked that bad boy up and started applying filters. After plotting my numbers into the Excel spreadsheet I was amazed how nasty the curve looked from 16hz to 80hz (where I have my crossover set at).

After applying 11 filters I now have a smooth line across the frequency span. I can't believe how smooth my SVS is now and how much better it blends with my Axioms. My wife even commented on how much better it sounded. That shocked me more than anything was what she said as she doesn't really take any interest in my HT setup.

So if you really want to "EQ" your sub and bring out it's very best add one of these babies to your setup and be prepared to be amazed.

Regards..
Rick

The next question: what the heck is a "home curve"? Apparently it's a downward slanting curve as opposed to a flat response line, and that for some reason that's good... but why would someone want one?

Rick:
I was seriously considering a BFD as well (especially since Behringer has a $20 or $25 rebate till the end of January) but I have one concern:

Doesn't any EQ you apply with the BFD apply only to one sweet spot? Have you remeasured in different locations, or is that not applicable to your room?

I've got a square room that's giving me problems!