This combination works best with a fourth order Linkwitz Riley crossover.

Here is the vented woofer box alignment.

MTM CONFIGURATION

Here is a vented box alignment for two Dayton RS 150S-8s.

Note that it requires a 3″diameter vent flared at both ends 7.25″ long.  This gives a max air vent velocity of 20 m/sec.

The max. spl is 109db, however output is limited by driver excursion from 50 to 100 Hz, reaching an spl of 103db at 65 Hz.

The cabinet should be well braced.  The volume displaced by the drivers, braces and crossover should be added to Vb to come up with Vt.  A rule of thumb estimate is Vb + 15 to 20%.

Place the drivers as close together as possible.

Half the internal surface of the enclosure should be covered by acoustic absorbing material.  The back wall should definitely be covered.  Rockwool type products are best.

The vent can be placed on the front or back.  Keep the vent 4″ away form any wall boundaries and drivers.

Here is the crossover for two Dayton RS 150S-8s in MTM configuration with the Beston RT002A.

If you want to notch the 15 kHz peak of the tweeter, use this parallel notch filter in series with the tweeter.

C =  2.002 µF
L =  0.05 mH
R =  7.95 ohms

Note: R should be adjusted by sub-
tracting from it the DCR of the coil.

Put the above components in parallel and out the parallel network in series with the tweeter.  At the high frequency range of the peak centered at 15 kHz, I doubt the sonic effects of this peak will be very noticeable.  I would build the speaker without this notch filter first and see how it sounds.

The crossover is third order for this MTM configuration, which will give the correct lobing tilt for this MTM configuration.

This entry was posted on Sunday, January 11th, 2009 at 12:48 am and is filed under Speaker projects. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.