# BK Monolith with REW + BFD



## -Ad- (Mar 24, 2009)

Hi from Adam in the UK.

Firstly, great site and thanks to all the useful information on here. I wouldn't have got to where I am now without it. Could you please critique my graphs and setup, and help me get the most out of my system :bigsmile:


- EMU configured through REW.
- Initial 75db config.
- 1/3 smoothing on all plots.

1. Speakers only
Speakers 3m apart on 6.5m wall. Sitting position 4m away on opposite wall. A bit far apart atm 










2. Sub only
- Monolith
- 10 oclock gain, 9 oclock phase, sat on right edge of tv cabinet.
- x2 REW automatic filters applied through BFD, and a few extra notch ones.
- 10db house curve applied after 'by ear' comparison of 32hz vs 100hz.
- Shelf filter at 366hz, -20 gain, 120/60 bandwidth: To bend sub curve to house curve line.










3. Sub + speakers together
- 90hz x-over through yamaha E800.










4.) All the above
- The 'green' speakers + sub together line had a massive dip at 93hz when they were ran together (don't know the theory, destructive inteference ???) so I kept the peak on the sub only graph at this point to remove the dip when both played together.
- Other peaks/dips at 45 and 75 when speakers and sub ran together.









Any ideas on the above and why it happens, gap in my knowledge. Overall it sounds great, and a house curve is amazing and just what the doctor ordered for bass impact during films. Any improvements to be made ? 

Will be getting a new processor this summer (probably the new Emotiva UMC1), so will have to go through all of this again :duh:


----------



## brucek (Apr 11, 2006)

> 1/3 smoothing on all plots


Smoothing should be limited to full range plots. Best not to use it for sub plots.



> 1. Speakers only


Best to select the correct target (i.e. bass limited mains @crossover), rather than lay a mains trace on a sub target.

Your mains are acting fairly nasty. I would measure each main individually and see where the dips and peaks are derived from. If each main looks good by itself, it's an interaction. If a main by itself is bad, it's a room reflection.



> 2. Sub only............9 oclock phase


Note that phase has no effect until the sub is combined with another speaker.



> Shelf filter at 366hz, -20 gain, 120/60 bandwidth: To bend sub curve to house curve line.


I would not do this. It's an old technique developed before REW offered the ability to create proper filters. Use REW to recommend filters (both auto and manual) until response tracks the target.
You'll note how your high filter drops the response too quickly.

I would correct the mains (if possible) with positioning, and then redo the sub without the high filter, then adjust sub phase with sub and mains together to smooth crossover and your response will be great.

brucek


----------



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

> - x2 REW automatic filters applied through BFD, and a few extra notch ones.


I'd recommend bypassing the notch filters. Typically you don't want or need anything narrower than about 6/60 to 8/60.


> - 10db house curve applied after 'by ear' comparison of 32hz vs 100hz.
> - Shelf filter at 366hz, -20 gain, 120/60 bandwidth: To bend sub curve to house curve line.


I'd like to see a "before EQ" graph to see if the shelving filter was necessary. Typically though, it'd only be useful if you had fairly flat response above the house curve target.

Regards,
Wayne


----------

