Inserts for PHL Mid/bass drivers had to be fitted.
closing the speakers off I had to measure the speakers with and without long wool.Basically
I tried to determinee how much
long wool should be placed in.
Here is a note from the designer after I took some measurements.
The idea is to have the back wave
absorbed as much as possible.
As for the absorption material quantity, it would be good to measure
impedance, as that will show the reactive component of the box loading, and
we need that as small as possible. However, the audition will show any major
problems if the stuffing is below some minimum that is needed Your measurements show too much room influence, and if you want to get rid
of the room reflections, place the speaker outdoors on the parking lot, side
down (so the speakers will be close to the ground) and then do the measurements.
Use thick felt on the sides close to the magnets.
Rings - Spacers had to be glued on. These spacers
adjust the depth of the driver (phl) to finish flush with the front baffle (Subdue
is time for the most precise job on the project,
cutting Subdue 909 on 45 degrees .We new it
from the beginning that this would
be the hardest job on this
project and it gave me a headache every time I think off subdues.
To be more specific and follow the design properly the
tweeter has to be mounted on the top of the ply only without any screws penetrating
to the other layer. In this case the tweeter is completely isolated with
bar from the box it self. The same scenario will apply to the Mid/bass drivers
completely isolated from the tweeter going the opposite way.
Note all this above is achieved only if all the pieces (top, bottom, sides …….are
mitered etc cut on 45 degree) so the wave bar meets all around and isolates the
We came out with two options:
First option is to cut the Front baffle first, as it has a 1 mm clearance for a spacer
to be glued for the mid/bass drivers (note that the mid/bass is not connected
to the subdue at all). Anyway cut the front baffle first, glue it, then measure
the sides do that then do the top and bottom and last do the back bit.
Second option is to cut all bits at once using screws to hold the individual pieces
the screws have to be removed latter so there is no penetration through the
2 layers (subdue 909 & Hardwood ply)
I decided to go for the second option.
First I cut the front baffle with (CNC).
It turned out to be too tight
the mid/bass drivers so I had to re cut it againand
ended up with 3.5 mm clearance