# BK Monolith DF EQ



## rectorydp (Aug 17, 2006)

Well I finally got hold of a BFD (DSP1124P) and managed to spend a little time working on the sub around New Year. When I first set up the sub and looked at the response in REW I was pretty horrified. I hadn't expected it to be quite as bad as it was. See below.









You can see that it is not pretty. I was particularly worried about the big dropout at 45Hz. So I decided I definitely needed a BFD. The crossover is set at 90Hz BTW and there is a slight house curve in the target response.

So I did a bit of work using REW and the BFD (REW is really excellent John :clap: and must have taken a great deal of work on your part) and came up with this.









I realise that it is not perfect but it does look a lot better to me. The bass is certainly cleaner. The original peaks were very audible as you might imagine. I didn't apply any boost but I did have to use quite a few filters. Having played around with REW and the BFD for a while I can see that I could use up lots of time trying to improve the response but I do wonder how much of the improvement I would really be able to hear :bigsmile: BUT I am certainly open to suggestions for improvement.

I also feel that the room would benefit from some work on the acoustics but I am not sure that approach would be too popular! I don't think that the sub is in the best position but there are limitations there as well!

Thank you to everyone providing such useful information in this forum. I would not have been able to make the improvements without this great font of knowledge.

I look forward to any comments.

BR
David


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## Wayne A. Pflughaupt (Apr 13, 2006)

Wow, can’t believe no one responded to this! Sorry about that, David.

I’ll throw out a few comments.


> The bass is certainly cleaner. The original peaks were very audible as you might imagine. I didn't apply any boost...


 That’s commendable, but I think it would be better to address those dips on either side of 40 Hz, and that droop between 17-30 Hz, than adhere to a strict “no boost” approach. 



> ...but I did have to use quite a few filters.


 It looks like you didn’t use any smoothing in your raw chart. Try using 1/6-octave smoothing – that way the response won’t look quite so “frightening” - which tends to encourage you to use more filters than you need, chasing every little wave in response. 

And by the way, don’t waste any filters trying to smooth things above 100 Hz!!

Don’t know if you figured this out, but you can manually apply filters and see “real time” the affect they will have. You can experiment with different bandwidths, cut or boost values, moving the center frequency up and down, to get the most improvement from each filter.

Regards,
Wayne


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## Sonnie (Apr 11, 2006)

Yeah... this one musta slipped through the cracks somehow. I bet brucek is wondering where this thread came from... lol.

Nice job on taming the response. I wonder can the Monolith handle boosting down low? 

You might try some various phase adjustments to deal with the 45Hz area... or maybe try a 60-70Hz crossover point if your mains can handle it. A little experimenting might pay off.


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## rectorydp (Aug 17, 2006)

Thank you for the comments. I was beginning to wonder if I had done something wrong!!

I will have a think about boosting. I can at least try it out. The dip above 40 is pretty significant so I am not sure what improvement will be possible. There appears to be a lot more headroom on the Monolith so it may be worth a shot.

I wasn't aware that people were smoothing their response curves. That makes me feel a bit better!

I didn't have much filtering above 100Hz but there is some. Originally I had not planned to do anything above 100Hz but it was pretty bumpy so I thought I might try it out. I will reconsider that.

I have tried some phase adjustments already and I think I have got the best result I can expect!

My mains can easily handle a lower frequency crossover but my processor cannot so I don't really have any options there :sad2: . 

Many thanks
David


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