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View Full Version : B-460 subwoofer - need help



markus_tirol
02-16-2005, 02:01 AM
I just purchased an original JBL B-460 subwoofer on ebay - (as an addendum for my 250 tis). At least it used to be original at some time ..... . It looks in good working order but it seems not to have a crossover built in . When I hooked it up it sounds like a (bad) wide band speaker - with a wide frequency range. I did not open the cabinet yet - so I do not know if it has or does not have a crossover.

Does anybody know about the B-460 subwooofer and which crossover it originally had.

Also I would like to know what is the supposed power rating for the amp to drive it properly.

I am from Austria - so please excuse my not perfect english...

:bs:

Steve Gonzales
02-16-2005, 02:22 AM
You need the BX-63 electronic crossover that was the mate for the B460/B380. You are correct in your impression of the B460's sound without this vital piece of gear as it does not contain any crossover internally. You can run any brand of crossover (as long as it is of high quality) if you cannot find the semi- rare BX-63. The BX-63 crosses the B460/B380's at 63hz. It sums the Low Frequency information of the left anf right channels and outputs them to a mono channel and an otherwise identical inverted channel to enable bridging a stereo amplifier. At least 300 CLEAN watts from an amp capable of delivering high current would be the bare minimum I would use, 1kw wouldn't scare me at all, just as long as you set it up properly and again, use a VERY high quality amp. Massive, clean and musical bass is what you will get once you find the JBL BX63 or another quality unit. You will also need to pay attention to placement in the room (as much as you can) and balancing the levels between your mains and the sub. Take your time. A few inches can make a big difference although it usually is more like feet in a typical set-up. You've got something special there. Good luck and don't be afraid to ask plenty of questions of the forum members. We also really like to see pictures. Regards, Steve G

4313B
02-16-2005, 04:14 AM
Does anybody know about the B-460 subwooofer and which crossover it originally had.Yeah, I think we've all owned a few of them at one time or other...

http://audioheritage.csdco.com/vbulletin/showthread.php?t=4557

http://www.lansingheritage.org/html/jbl/specs/home-speakers/1983-b380-b460.htm

mrbluster
02-16-2005, 09:28 AM
[QUOTE=Steve Gonzales]It sums the Low Frequency information of the left anf right channels and outputs them to a mono channel and an otherwise identical inverted channel to enable bridging a stereo amplifier.......... Since Bridging would cut the dampening factor in half, and the amplifier would see a 4 ohm load (B-460), in (for example) the case of a 200 watt stereo amp, would this necessarily be an improvement over using one channel? Opinions, suggestions?

Thanks,
Mrbluster

Zilch
02-16-2005, 09:47 AM
See the information Giskard posted for you above.

I run B460 directly from the subwoofer output of my preamplifier through a bridged JBL 6260 amplifier. While I do have a BX63A crossover, which has additional features like adjustable crossover frequency (63-125 Hz), I have never used it, since B380 and B460 sound just fine without it. Room response seems to enhance the bass they deliver more than enough for me.

I would not bridge any amplifier that is not specifically made for that. Those typically have a switch to provide their own input inversion on one channel, and no external hardware is required.

Mr. Widget
02-16-2005, 10:15 AM
Many folks on this forum seem to like bridging amps. Most of the amps I own have a bridge switch built in and yet I still prefer the sound of 3dB less watts and better damping factor (woofer control). When I need a single channel I just use half the amp... it just sounds better. With most amps if you only use one channel you are taxing the PS less so you also have greater current capacity. Give it a try.

Widget

Zilch
02-16-2005, 10:23 AM
I still prefer the sound of 3dB less watts and better damping factor (woofer control).'Course you could easily get the extra 3 dB AND the damping control by simply running TWO B460's in stereo. :bouncy:

That way, half of the amp isn't sitting idle all the time. We believe in mantaining balance and equilibrium in the universe wherever possible.... :p

mrbluster
02-16-2005, 12:05 PM
[QUOTE=Zilch]'Course you could easily get the extra 3 dB AND the damping control by simply running TWO B460's in stereo. :bouncy:

Now that is an answer with some thinking behind it! I am impressed.
Don't know where I can find a second B460 right now, but while I am looking, do you think I could use a SUB1500 in a 6 cu.ft. Olympus cabinet as a reasonable substitute? It is the best I can do at the moment.

Mrbluster

Zilch
02-16-2005, 12:24 PM
That sounds like a reasonable interim compromise. :yes:

[Play gently with that Olympus, tho. It's not all that well braced for sub use, and Sub1500 will render it kindling if ya crank it....]

4313B
02-16-2005, 12:51 PM
Don't know where I can find a second B460 right now, but while I am looking, do you think I could use a SUB1500 in a 6 cu.ft. Olympus cabinet as a reasonable substitute? It is the best I can do at the moment.You need ANY B460's with SUB1500's around??? That's bizarre! One of the major points of owning a SUB1500 is to get away from the huge enclosure volume requirements...

mrbluster
02-16-2005, 01:19 PM
Just daydreaming. You know the old agage, "there's no substitute for CUBIC INCHES"

Mrbluster

4313B
02-16-2005, 01:22 PM
:p Yeah, yeah. I'll take a 327 mouse in a 3,000 pound car over a 427 rat in a 4,000 pound car anyday. ;)

... but that 427 sure is fun in a 3,000 pounder! :rotfl:

Steve Gonzales
02-16-2005, 01:30 PM
I just wanted to tell him that JBL included that feature and choice. I guess if you are worried about dampening factor, your choice of amp would have to revolve around that and low impedence drive capabilities. I have run my m80's bridged and had no problems in real world conditions. I didn't notice a lack of control, just more power. It guess it must depend on what you are using.

John
02-16-2005, 02:25 PM
I have a Harman Kardon Citation 16 that I want to try with my B460. I know how to bridge it with the internal jumpers,but what input do I use and which speaker outputs would I use as well???

Robh3606
02-16-2005, 02:36 PM
"I know how to bridge it with the internal jumpers,but what input do I use and which speaker outputs would I use as well???"

The manual doesn't tell you?? Anything under the cover?? or near the jumpers??

On a Crown it's channel 1 as input channel 2 off and the output is taken off the two + leads. For yours?????


Rob:)

4313B
02-16-2005, 02:41 PM
I just wanted to tell him that JBL included that feature and choice.Yeah, there seems to be a fundamental lack of understanding about the design of the BX63 and B380/B460...

It guess it must depend on what you are using.True enough. Amps like the Citations and Adcoms have the requisite balls to power reactive loudspeaker loads regardless of stereo or bridged mode.
I have a Harman Kardon Citation 16 that I want to try with my B460. I know how to bridge it with the internal jumpers,but what input do I use and which speaker outputs would I use as well???

http://manuals.harman.com/HK/Owner%27s%20Manual/CitationSixteenOM.pdf

http://manuals.harman.com/HK/Service%20Manual/CITATION%20SIXTEEN%20sm.pdf

http://manuals.harman.com/HK/Service%20Manual/CITATION%20SIXTEEN%20ADDENDUM%20sm.pdf

Steve Gonzales
02-16-2005, 05:11 PM
Giving advise on this forum is interesting. I love all the different trains of thought. I've always had to research and do trial and error to figure out my own set-up and I've enjoyed every minute of it!. There are alot of options because of all the different types of equipment out there. I've found that you've got to find out what works for YOU. What is also important is to know all the options. This was the case with the Yamaha M80 amps I use. Yamaha's own rep said "We do not recomend bridging these amps", but their original owners manual showed the opposite to be true. I had to think about why the difference in recomendation. Probably legal was my thought and I hooked them up as per the manual's instuctions and it worked out just fine. So, I just wanted to let him know that this option was one way to go. One other instance is, my choice to go with an aftermarket diaphragm in my last pair of 076 tweeters. I figured that if anything, it would be a good learning experience. Well, I was able to do a side by side by side A-B-C real world critical listening test between an original badged pair, a 2404H motored/original 2404H diaphragmed pair and the aftermarket diaphragmed/ Alnico motor/076 lens pair and in what I, IMHO, call real world conditions, cannot tell the difference. In extention, smoothness, power handling and other critical aspects of performance, it is a virtual dead heat. So, if I would have listened to what others said (absolutely) without trying it for my own self , I would not know this. I realize that there is the fact that my ear may or may not be critical enough, the bottom line is that it works to my contentment. So, I urge all budding JBL "nuts" to consider ALL the information and find out what works for them. This is THE PERFECT forum for finding out these very things.

mikebake
02-16-2005, 06:08 PM
Many folks on this forum seem to like bridging amps. Most of the amps I own have a bridge switch built in and yet I still prefer the sound of 3dB less watts and better damping factor (woofer control). When I need a single channel I just use half the amp... it just sounds better. With most amps if you only use one channel you are taxing the PS less so you also have greater current capacity. Give it a try.

Widget

Funny, that is what I have long done, too. Always seemed to like it better not bridged, so I stopped doing it.......

John
02-16-2005, 08:30 PM
Thanks Giskard I should be able to figure out what I need to do,now that I am armed with the tech manual for that 55 lb. beast.:applaud: