JBL 4345 in Sansui EC146 Cabinets?

[kelossus]

I've managed to pick up a pair of Sansui EC146 cabinets for a very good price. The EC series in Japan was a somewhat modular cabinet made by Sansui populated with a variety JBL components.

Luckily I have all the drivers on hand and intend to build these as biamp only with a biased passive network for the top 3 drivers.

The question I have is regarding the cabinet volume of the Sansui EC146 vs the original 4345. The 4345 is 8.8 cubic feet while the Sansui is 7.6 cubic feet. Roughly 15% smaller. I can change the port length to mimic the 4345 tuning but will I require bass eq like used in the b460? Actually, does the 4345 have any bass eq when biamped with the factory 5235 network? I believe the 4355 and 4345 crossover cards are the same so I don't think it has eq built in. Which makes me question why the B460 at 8 cubic feet required bass boost but the 4345 didn't?

Below is a pic of the EC146.

 

[powerman]

Hello Kelossus, I will try and answer some of your questions. The JBL 4345 is tuned at 32 Hz I do not know what the Sansui EC146 is tuned to. Maybe 32-35Hz. The JBL B460 is tuned at 26Hz. The 5235 cards for the 4345/55 speakers are set at 290hz with no EQ. The JBL 5235 electronic crossover has different settings the user can pick.
Dual position DIP switches set at 20/30/40Hz with a maximum boast of 6db/Q2. The 20hz setting mimics the BX63 or A used to extend the response of their B460 sub. The B460 used the Q2 boast at 20 Hz to give the speaker a F3 of 26Hz. The B460 was designed as a true sub and bandwidth limited and usually crossed over in the 60 to 80Hz range. How did you come up with the cubic feet for the Sansui is it by their specs. If so maybe they took into account the displacement variables for the drivers and such. There is a great article with Greg Timbers in the Audio Aug1983 issue on the 2245 driver for 8cuft and 12cuft with this EQ. Hope this helps with your questions.
https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/80s/Audio-1983-08.pdf
Starts at page 60

 

[kelossus]

Hello Kelossus, I will try and answer some of your questions. The JBL 4345 is tuned at 32 Hz I do not know what the Sansui EC146 is tuned to. Maybe 32-35Hz. The JBL B460 is tuned at 26Hz. The 5235 cards for the 4345/55 speakers are set at 290hz with no EQ. The JBL 5235 electronic crossover has different settings the user can pick.
Dual position DIP switches set at 20/30/40Hz with a maximum boast of 6db/Q2. The 20hz setting mimics the BX63 or A used to extend the response of their B460 sub. The B460 used the Q2 boast at 20 Hz to give the speaker a F3 of 26Hz. The B460 was designed as a true sub and bandwidth limited and usually crossed over in the 60 to 80Hz range. How did you come up with the cubic feet for the Sansui is it by their specs. If so maybe they took into account the displacement variables for the drivers and such. There is a great article with Greg Timbers in the Audio Aug1983 issue on the 2245 driver for 8cuft and 12cuft with this EQ. Hope this helps with your questions.
https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/80s/Audio-1983-08.pdf
Starts at page 60

I got the cubic feet from the spec sheet on the EC series. Adding up the volume of the cabinet (subtracting the material thickness and recessed baffle) it's obvious Sansui have accounted for the driver displacement in their figures. With the internal wadding I think the cabinet would be close to 8 cubic feet.

Good to know no bass boost is required. I can check the cabinet tuning and build the biased networks to suit. Cheers!

 

[donprice]

Are the EC146 ports removable? Based on other posts/photos, it appears so. If I were king, I would fab up a second set of ports to mimic the lower B460 tuning and add a miniDSP or similar to dial in the required EQ boost (6db @ 26Hz Q=2.0) and a protective filter below 20Hz and let 'em rip.

Of course you could always pull the DSP/EQ and pop in the "4345 tuned" ports if you decide you like that better.

Good luck!