View Full Version : Almost there!

07-16-2005, 06:57 PM
Got a 2245H 18" woofer off of eBay. And a surround kit for the future. Guy threw in the cab for shipping expense. 3/4" MDF.

Internal dimensions are 27.5" x 19.5" x 42.5". Port is 8" x 8" x 20.75". Port exits one end of the box and the driver is below it.

I am using a Carver TFM-22 strapped mono for 350w into 8 Ohms.

I have a JBL/Urei 5235 Freguency Dividing Network.

Given the dimensions, port and driver what should I be using for a crossover point? The 5235 is currenly set for 800Hz. That is too high. I plan to change the channel 2 board in the 5235 so I can take the LF from channel 1 and feed it to channel 2. Channel 2 would be set to give LF at the needed point. That will got to my pre-amp (for volume control) and then to the Carver.

Does JBL still offer the 8630 boards populated or blank?

07-16-2005, 08:05 PM
Boards for 5235 are NLA from JBL. They do occasionally appear on eBay, or you buy an earlier model with the board(s) you want for cheap.

Your box is tuned to 21.84 Hz, with net volume 12.16 cuft. assuming typical internal damping. 2245H will play fine in it, up to rated 300 W. Enable the high pass filter in the 5235 at 20 Hz; your driver runs out of cone displacement at 18 Hz.

If you're just using it as a sub, I'd find the 18 dB 80 Hz card and use that.

Cursor's at -3 dB. If you enable 5235's Q=2 bump filter at 20 Hz also, it'll play flat down to 25 Hz, but cone excursion will limit you to about 180 Watts.

Wait for someone else to confirm this. I'm new at using BB6P. :)

Not sure about your "running it back through the preamp" scheme. Doesn't sound right, but you know your gear better'n me....

07-16-2005, 08:32 PM
Carver CD goes to Adcom pre-amp. AudioSource EQ in pre-amp processor loop. Output goes to Carver M-500t main amp feeding pair of L300s. Using Tape out of EQ into a Carver C-1 pre-amp. Output of C-1 feeds a Y cable that feeds a channel of the 5235. The LF output feeds the left input of the Carver TFM-22 strapped for mono ops.

The C-1 is needed so I can control the volume of the sub independently of the main speakers.