Step By Step Sub Equalization using BFD and ETF (1 Viewer)

[Doug Fraser]

I am in the process of finishing a Stryke 5.2. I currently have 2 - 10 AVI sub's in the HT room but they have an F3 at 42 Hz and I want to go lower...therefore the Stryke.

Even with 2 subs, my in room response has a huge peak at 50Hz similar to Jon M.

For those of you who have equalized out their sub's in room response with a parametric equalizer I have a few questions.

How many EQ bands did you use?

Where the 12 bands per channel on the BFD enough or did you have to run the 2 channels in series to use 24 bands.

I would be real interested in seeing the EQ that Jon M (or others) applied (centre freq, BW and gain) to flatten out the in room response.

Thanks

Doug

 

[ThomasW]

I would be real interested in seeing the EQ that Jon M (or others) applied (centre freq, BW and gain) to flatten out the in room response.

Here's a plot of the actual EQ applied to the AS-15 box, that's a ported HE-15. Only 3 bands of EQ were needed.
Link Removed

 

[Shawn Fogg]

Pete,

"This may be a problem when running long cables into another room. I was getting exaggerated distances, and I think it's because of the length of cable. "

It won't. You would need thousands of feet of cable (or more) to make much of a timing difference.

Were you inputting the signal into a straight dedicated pre-amp or into a surround sound receiver/processor? If it was any sort of surround sound equipment the inherent delay in going through the A/D, DSP, D/A is probably all you were measuring. Could have been the delay introduced by the BFG itself too.

Shawn

 

[Pete Mazz]

I had the output going into my B&K 307. Some sttings were taken with it set to analog bypass, others weren't. I don't remember which was which, tho. I'm going to just wait until the mic/preamp arrives and start playing again. I don't have an EQ, and, hopefully won't have to use one. I have a single notch filter in the B&K that I've been using to tame the worst peak, and so far it's been enough.

I got different FR graphs from using ETF than from doing it with sine waves and SPL meter. I assume the sine waves are exciting the room more than the MLS tone from ETF, but not sure.

Pete

 

[FrankD]

Pete please let us know how the mic and preamp from ETF works vs the Radio Shack unit. I was also thinking of buying the mic and preamp from ETF.

I used the Radio Shack unit with a test tone generator and compared that to the Radio Shack unit and my laptop with ETF demo software and I seemed to get differences too. My Radio Shack unit with test tone generator indicated that my sub frequancy response curve was flat (using Behringer 1100p with filters) but when I checked it with my laptop and Radio Shack meter the frequency curve did not appear flat???

Regards

 

[Rick Radford]

FrankD,
I bought ETF yesterday, so I am still much in the learning curve on it.
If the info I've gleaned thus far is correct, you won't get accurate results with just any test tone cd. I believe ETF requires MLS tones for accurate results. So I think this rules out using the Stryke, Autosounds 2000, and homebrew test CDs.
You can d/l MLS test tones here.
Then use the Test CD option under Measurement when you take a new measurement. At least, that's how I think it works.

 

[Pete Mazz]

The mic and pre-amp came in today. Looks like this weekend, if time permits(NFLplayoffs), I'll do some tests. I hope it works as well as it looks.
Looks like True Audio will soon offer a RTA software package, as well. It will also function as an oscilloscope, signal generator and multi-meter. It will be offered at different price points for whatever functionality you want!
http://www.trueaudio.com/truerta.htm
Pete