got my bfd - first graph i need help

[miker916]

Hi all,
i have just started using REW 4.0 and have purchased a bfd. The sub i have is a BK Monolith but my first attempt at a graph dosen't look right. The bass looks to tail off a lot after 32Hz. I thought the Monolith would be a much better subwoofer than that? I calibrated the sub @75db using my radioshack spl meter and am using the spl correction file. What can i do to improve the lower end, the sub gain is only at 25% at the moment. I can increase the gain so that the response at 20Hz is on the target line but i get a warning when trying to find peaks and REW wants to add 20 filters to lower the rest of the response. My sub is in the front right corner (only place i can realistically place it). I'm completely new at this game so i apologise in advance if i'm asking some stupid questions, but any help/advice would be greatly appreciated.

Thanks
Mike

[Wayne A. Pflughaupt]

It’s not really “tailing off” below 32 Hz – you just have a peak there that needs to be dealt with. Eliminate it with the BFD and you’ll have solid response down to 20 Hz.

What can i do to improve the lower end, the sub gain is only at 25% at the moment. I can increase the gain so that the response at 20Hz is on the target line but i get a warning when trying to find peaks and REW wants to add 20 filters to lower the rest of the response.

That’s because at that point the other frequencies are super high.

It doesn’t look like the target line is going to do much for you in this situation – at least not initially. Try setting a couple of filters to pull down those peaks at 32 and 89 Hz, then re-calibrate your levels and take another sweep. At that point you should closer to the target line, and you can apply other filters to finish up. Remember the idea is to improve response, so don’t over-do the number of filters trying to make it “picture perfect.” IOW, as long as you can get response approximately along the target line, it’ll sound great.

Regards,
Wayne

[miker916]

Thanks Wayne, i've applied the 2 filters as you suggested, it's looking a lot better already and more importantly sounding much better. Is it a good idea to try and reduce the 80-200 range?

[Wayne A. Pflughaupt]

Just hit those two peaks below 100 Hz and you’ll be about done. However, if you’d like stronger response below 20 Hz, you might work on smoothing down the range between 20-40 Hz.

Regards,
Wayne

[Blaser]

Hi Mike!

There's never such thing as "stupid questions", everybody's learning everyday! What's the dimentions of your room? Is it a big one?

You equalized FR is fine IMO. Just follow Sir Wayne, and it will be a big win!!

B Rgds
Blaser

[miker916]

Thanks guys,

response looks much better now. It really is amazing the difference a BFD and the excellet REW software can make to your sub.