Dual 505 Freq Sweep

PolkThug

This has been a fun little project. I think I need to work on the room acoustics. I have two PSW505's stacked and corner loaded. For this test I put the Onk on a volume of 45. I would have liked to run it hotter but the bass police was home. I have individual tones for 20-99Hz.

It was interesting to see which parts of the walls vibrated at different frequencies. I found that a vent in my ceiling makes an awful metal on metal vibrating noise at exactly 84Hz, no less, no more, just exactly 84Hz. I found that my loudest point is 48-49Hz, at 102db. My weakest point was at 20Hz, at 76db. It was really cool to see the db meter move at 20Hz, even though you couldn't really hear much of anything.

Obviously, I would like my peak to be at the 30Hz and lower area. Maybe its just not possible, or maybe it is with the right room acoustics. Any pointers?

Regards,
PolkThug

gatemplin

Are those corrected?

That graph is not bad at all. Sure there is a slight hump at about 50 Hz but nothing too bad. You can get lower extension and a peak below 30 Hz with an PEQ, but you risk bottoming out the drivers below the tuning frequency. Try correcting the values if you havent already and you will see that the graph will have better extension.

PolkThug

I didn't make any corrections. I think I remember something about you have to add db's at lower freq's for the Rat Shack meter. Can't remember the formula.....

gatemplin

Yep you have to add dBs, Pjdami posted the the correction factors in this post. http://clubpolk.polkaudio.com/forum/showthread.php?s=&threadid=17924&perpage=30&pagenumber=2

Where did you get your test tones from?

PolkThug

Thanks.

Bass Mekanik 5.0

Money well spent. I'm going to go through this process again and isolate all my "vibrating spots" in the room. I got some Tsunami Silencer to put behind the walls where necessary and on my vent that likes to scream at 84Hz. lol

PolkThug

:-)

Tour2ma

PT,
Since you're "expermintin' "... try draggin the stack about half-way out of the corner... One direction and then the other...

102 dB??? Not a very strict police(wo)man is she?