4645B Subwoofers question

[Rudy Kleimann]

Hi guys, I run a couple of 4645B subs Sound is great, punch is amazing but i expected some thing better on the very low frequencies. After a tone test it is no present anything under 33hz I was expecting to reach 25Hz

You need to provide a 2nd order peaking high-pass filter with a Q=2 tuned to 25Hz to get the 4645B to do its magic. The 4645B, with its' two 5.25" diameter x ~24" long port tubes, is tuned to ~23.3Hz, perfect for the 25Hz peaking filter. I have one in my living room, driven through a slightly modified JBL 5235 active crossover. It has a built-in switchable 2nd-order peaking high-pass filter with settings to peak at 20, 30, OR 40Hz, and switchable mono summed LF output. I changed the filter caps to peak at 25Hz, per forum member 4313B's instructions. WINISD modeling indicates it to produce 24-55Hz +/- 0.6dB I'm very pleased with the results. The 20Hz stock filter setting in the 5234A and 5235 is ideal for the 2245H in a 12 cubic foot box tuned to ~18Hz.