Attention - B&K Pre/Receivers Owners - Info on B&K Notch Filter adjustment

polkatese

All,
For those owners who has B&K pre/receivers with room compensation/ notch filter adjustment feature, here is a step-by-step layman instructions on how to use it. I had mine for almost 6 months and couldn't really know how to do this right, until I stumbled into this instruction on AVSForum. I just finished adjust mine, and it works! Turned out I have hump across 58 Hz to 70 Hz. I compensated mine to -14 dB across this range and now it sounds better. Give it a try:

Here are some wonderful instructions that made this easy for me which were posted by Longshanks DVD @HTS. A big thank you to Mr. Longshanks:

1. You need a rat shack meter, patience, pen & Paper (BTW-this whole thing is done just like setting your speaker levels)

2.In the speaker EQ menu in the set up select "NO" for THX boudary comp (which turns things down at 60hz and 20hz...why would anyone want to get rid of 20hz?)

3. Next I would select the freq which your x-over point starts (i.e. 80hz for THX)

4. Play test tone at that level (I just used the first one offered and write down the results. Turn it off after you write it down before selecting the next.

5 Go back to the freq field and go down a notch (it goes in 2's i.e. next would be 78hz)

6. continue steps 4 and 5 until you hit 20hz (the bottom)

7. More than likely you'll see a pattern where there is a number of freq. which are much higher than the rest of the freqs and one "notch" that is the highest. This will usually be in the boomy ranges 60-35hz.

8. select this frequecy as the "notch" -there is a field to select the notch.

9. next you need to select the bandwidth width (i.e 30hz to 40 hz if that was the width of the hump). The more of the freq that are too high, the wider the width is to set ,if its only 2 or 3 offender freqs then make it more narrow.

10.From this point start at -3 to bring the area of the hump DOWN (NEVER RAISE THE LEVEL/This will only compremise your sub performace)

11. Go back now and play the trouble freq. areas again and see if it was enough (if not keep droping by -3s) to bring the numbers close to the majority of the readings (write down findings for reference)

12.Thats it (hope I wasnt too confusing)... -exit the menu and reset your sub level and enjoy!

polkatese

All,
this is the result of my calibration of the notch. I want to get your opinion if I do this right, so, when you have a minute, could you take a look at the excel spreadsheet and let me know if it makes sense and if I missed anything.

Dr. Spec, thoughts and comments please?

What I noticed after the calibration: low is tighter, midrange is *very pronounced* improved, to the point that the details its producing sounded a teeny weeny harsh (especially noticable is old recording's hiss due to less than ideal transfers.) But, the upside is, there are so much details *literally* that were veiled/overwhelmed by low now comes out (i.e. vocal sigh's, percussions, etc.). Instruments (especially piano) sound like what it should be, stereo imaging is more distinct and clear.

Thanks in advance..

mantis

polkatese,
nice way to help other B&K brothers out.

But.....

If you didn't know how to use the notch filter,you could have asked my man.I think it's one of the very best features that B&K offers.It works very well in all rooms I have tried it including 2 of mine.

They where suppost to add multiable filters to the avr507 but it didn't happen...........but it's coming in a secret shady underground up and coming new Preamp.......stay tuned.

Dan

polkatese

Dan,
yeah, I know, I got sidetracked until this post came out. Back when I just got it, I read the manual a couple time, and it doesn't register. It was only a half page of instructions, more on changing the values, as opposed to explaining the objective and what to do.

multiple filters would be neat, I guess the upcoming upgrade would be interesting. Thanks for the heads up.