Want to build bass cabinet for Fender BXR 300

[timzog]

I really liked Sreten's idea of the 2 8 Ohm cabinets (4x10 and 15). In general, I will rarely need all the power of this amp so what I would like to do is build the 4x10 cabinet and if I ever get back into big gigs, I would build the 15 cabinet too. Could you give me some specifics on the cabinet dimensions, connections, and where to position everything? Also, if it is vented, what is the best way to vent it?
Thanks,
Timzog

[sreten]

Nothing is particular critical in designing / building a bass cabinet.

Build it out of 1" spruce ply (housing grade) for strength and
reasonably light wieght, you need to consider covering, side
handles, corner protectors, feet, grill, and type of connector.

I'll stick to feet and inches here :

A 4x10 is going to be about 2ftx2ft frontal aspect, with 1" stock
this will give a CSA of ~3.3 ft^2 and you adjust the depth to
give the required internal volume, taking into acount the recess
of the baffle to allow a grill to be fitted.

Total depth varies from around 13" to 19" giving a
range of ~ internal volume of ~ 2.5 cuft to ~ 4.4cuft.

A 4 string cabinet shoulds be tuned to around 40Hz, 5 string 30Hz.

First off though you must be specific about the driver that is going
to be used, and whether you want to include a tweeter or not.

sreten.

[timzog]

Thanks!
I welcome your advice on the driver choice (You previously suggested these http://www.partsexpress.com/pe/show...tnumber=290-380) and I would prefer to add a tweeter although I would need some help with choosing that too and figuring out how to do the crossover and wiring. Reagarding the construction, I am a woodworker so I am not worried about figuring out how to join it all together. Where can you get some attractive grill material?

Timzog

[sreten]

Well if your going for the PE drivers :

I'd say a sealed enclosure would be best for a reasonable sized
4x10 top enclosure for use with a bigger 1x15 bottom cabinet.

I'd suggest a 24"x24"x15" sealed enclosure, well stuffed.

(the added 1x15 reflex would be ~ 20" deep)

Minimal bracing is front to back, personally i'd go for an 8 brace
front to back vertically offset somewhat with the handles fitted
above this.

Grill material is more about protecting the drivers,
generally very open weave nylon on a frame.

The tweeter is set central to the 4 drivers, usually a square set
with the corners vertical and horizontal to fit inbetween the 4x10.

I'll get back to you on the tweeter and c/o.

sreten.

[sreten]

For the tweeter I suggest an Eminence APT-80.

http://www.partsexpress.com/pe/showd...number=290-532

the 4x10 drivers I suggested should be around 100dB/W together.

As the tweeter is 105dB/W it needs padding back with
an adustable L-pad, this will ~ double power handling :

http://www.partsexpress.com/pe/showd...number=260-268
http://www.partsexpress.com/pe/showd...number=260-252

Rotate the L-pad housing so normal is your preferred level.

An 18dB/octave crossover should precede the L-pad.
I'd say at 4.5kHz to 5kHz, 4.8Khz gives :

http://www.mhsoft.nl/spk_calc.asp#crossover

C1 :
http://www.partsexpress.com/pe/showd...number=027-416
C2:
http://www.partsexpress.com/pe/showd...number=027-426
L1:
http://www.partsexpress.com/pe/showd...number=260-719

The tweeter may gell better with the 4x10 wired out of phase,
also note used on its own (not on top of a 1x15) close up the
tweeter will be difficult to hear unless the cabinet is tilted back.

sreten.