JBL B460 Subwoofer QUESTION

[Andersen]

Hi All
I will have one B460 speaker (without the BX63) arrive in few days and plan to build a 2nd order passive crossover cutting at 70hz. May I ask if it's ok to just connect this subwoofer through the passive crossover and to a normal stereo amplifier either L or R speaker outputs?

Thanks and regards
Andersen

 

[loach71]

Passive Filter

Hi All
I will have one B460 speaker (without the BX63) arrive in few days and plan to build a 2nd order passive crossover cutting at 70hz. May I ask if it's ok to just connect this subwoofer through the passive crossover and to a normal stereo amplifier either L or R speaker outputs?

Thanks and regards
Andersen

This MAY work -- but it will not be optimal. You need a LOT of clean power to drive the JBL 2245H driver -- which may not be available in a "normal" stereo amp. I suggest a good active crossover with adjustable crossover frequencies. I use BGW 750C power amps with a variety of JBL2245H based enclosures.

 

[HiFiCanada]

Hi All
I will have one B460 speaker (without the BX63) arrive in few days and plan to build a 2nd order passive crossover cutting at 70hz. May I ask if it's ok to just connect this subwoofer through the passive crossover and to a normal stereo amplifier either L or R speaker outputs?

Thanks and regards
Andersen

I had it that way for years, the 2245H will still produce plenty of very low bass, it's not the perfect way to set that up.

 

[HiFiCanada]

Autually I should add that I had the Harmon Kardon PM665, using the left channel and bumping up with a EQ, no crossover, still surprising how much sub bass that can add.

 

[Andersen]

Many thanks for your replies. My concern is if there is any identifiable imbalance for just using left or right channel to feed the sub-woofer?

 

[Bigears]

I have a B380 and BX63A powered by a bridged PC-2002M and I would not use any less power. JBL in their white paper suggests a minimum of 1000 watts. I ran a BGW 750E which I think is close to 1000 watts bridged, however the Yamaha is noticeably cleaner. I used this setup with my XPL-200A's...the real value with an ULF sub is reducing the cone distortion on the main woofers which really cleaned up the LF from 100 Hz and lower.

Here's a shot of my B380 BX63A before the refoam. Don't use it much anymore...may turn it into cash for other gear.

 

[Bill Shenefe]

Years ago I acquired a JBL 2245 when the big sub came out. I built an 8 cu ft box using 1.25 inch MDF and bracing. I used a single front port with 6 inch diameter pvc schedule 40 pipe ad an elbow to allow the needed length of port. I ran it with a bridged Heathkit 250 W/ch amp that had 3 db headroom and would occasionally light up the full power leds on the amp. I tried to make a good active crossover but the card for the JBL crossover had a crossover frequency 63 cps and a boost with the box tuned to 24 cps I think from memory with a subsonic filter below that. I found that for music it really did not much for my music system which at the time was a pair of home built JBL L-300s which had all stock JBL crossovers and speakers. They were great, flat down to about 30 cps in my room and the sub really didn't do much other than take the punch out of the low end that was already there, probably since I could not match the bx63 crossover characteristics. . Later I added the 10 inch midrange with JBL crossover parts and circuit design to make a 4343 pair. These still did not like yet another crossover yo bring in the sub but I did get away with going active on the crossover to the 136A woofers at least. Again wanting to use my big sub I tried it for home theater but settled on a pair of SVS PC13 ultras to go to lower limits than the JBL for the home theater sound effect range. I do however use my second set of home made cabinetry L-300 side channels with a center channel using a smaller cabinet and 12 inch JBL woofer but retaining the super clear le85 horn driver and 077 slot radiator. To my dismay I was never able to see or hear a real B460.

 

[mech986]

Hi Bill,

Welcome to AK!! Sounds like you had some interesting experiments there. Today there are other active crossovers which can mimic what the BX-63 could do, as well as adjust the boost available to you. Some rooms just don't work very well with an 18" subwoofer, and a lot of music just doesn't have much content down there.

If you get a chance, show us some pics of your DIY speakers, maybe put them into another thread such as an introduction thread. What have you done with the 2245H and its cabinet?