|   sub placement | ned
Jan 11, 2002 9:47 AM | | where is the best place to put my sub? |
| re: sub placement | paulbl
Jan 11, 2002 10:22 AM | | Sounds like job for Richard "ace of bass" Greene! Start with a corner near your mains, this is usually a good starting point. Sub placement is VERY room dependent, and requires a lot of experimentation with placement as well as xover and level controls. My sub sounded better (less boomy) when moving it out about 3 ft. or so from the corner. |
| re: sub placement | rned
Jan 11, 2002 11:40 AM | | is there a rule for xover and level controls? |
| sub woofer .. placement .. in ........4.......EASY ...... steps | Richard Greene
Jan 11, 2002 12:57 PM | | (1) Put sub in corner near one of your front speakers or in the corner closest to your ears for maximum output and minimum harmonic distortion (with at least six inches between driver and nearby wall(s) to reduce wall rattles).
(2) If any wall near the sub or the floor below the sub rattles,
use concrete patio slabs (Home Depot) leaning against the wall(s) and/or under the sub to silence the rattles. The slab needs to be under a down-firing sub driver ... but must extend IN FRONT OF a
forward-firing sub driver.
(3) Buy bass traps for every available corner or build them
(see link below)
http://www.geocities.com/jonrisch/basstrap.htm
(4) Buy parametric equalizer to reduce SPL of loud bass resonances caused by standing waves. If you had enough bass traps you would not need equalization, but with a corner sub three traps in the other available corners is probably not enough.
See link for a cheap Behringer digital equalizer - fine for use with subs, but not good enough for use with main speakers, in my opinion:
http://www.lentine.com/pa/items/78818.stm
NOTE 1:
If you have no available corners (like me) or the wife hates
bass traps (most wives) or you simply don't like the way they look,
then skip the bass traps
NOTE 2:
If your sub is in a corner, the output at 150Hz. should be down at least 24dB so the sub will be sonically invisible almost all the time
That requires approximately:
- 24dB/octave low-pass filter at 80Hz. or lower
- 18dB per octave low-pass filter at 60Hz. or lower
- 12dB/octave low-pass filter at 40Hz. or lower
Two 12dB/octave filters at the same frequency adds up to 24dB/octave
NOTE 3:
If you want to hear the bass frequency response including room resonances at your seating position, use the Stryke.com Basszone test CD track 5 slow sine wave frequency sweep. Keep the volume low in the first minute (1Hz. to 20Hz.), especially if the sub is ported.
(See link below)
http://www.stryke.com
click on "test CDs" & buy Basszone Test CD volume 1
NOTE 4:
If you want to measure the bass frequency response too, also buy a Rat Shack analog sound meter and use C-weighting and Fast response.
Add about 6dB at 20Hz, 3dB at 25Hz. and 2dB at 30Hz. to convert from
the C-weighting to an unweighted dB scale. The Rat Shack meter is not very accurate below 40Hz. (or above 2000Hz.) -- so the adjustments are just rough estimates.
WARNING:
If your room is cubical, square or near-square, your sub may sound better placed right next to you (near field) rather than in or near a room corner -- near field "middle-of-the-room" locations will usually require significant bass boost (equalization) below 50Hz. and may not sound very good at OTHER seating positions.
If your room is not rectangular or L-shaped, there is not enough data to say whether a corner is a good place for a sub or not. You should buy a slow sine wave aweep and sound meter for measurements. The theory that you can place a subwoofer in your chair and walk around the room to find the best sub position is nonsense unless you use test instruments, NOT YOUR EARS. |
| sub woofer .. placement .. in ........4.......EASY ...... steps | Mr2A
Jan 11, 2002 1:15 PM | | Excellent info. Mr. Greene! thanks very much! |
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