How should I hook up my B380?

[Gary C.]

I've got a couple of Yamaha M-80 power amps,and also an M-630.
They don't have a subwoofer connection on them,and I'm completely ignorant of how to do this.Never owned a sub before now.
Is there something I can put inline between the C-80 control amp and the M-80 power amps,that will only send the correct frequencies to the B380?
Or if the B380 is fed the entire signal,will it only reproduce the notes in the appropriate range?And would it be best to bi-amp,so the B380 is getting its' own power?
Any advice greatly appreciated,as I've never had to wire up one of these before.

[pmakres1]

Ideally, you would use the JBL BX63 Electronic dividing/summing network. This is inserted between the preamp and power amp (s). The unit crosses over at 63 Hz, and provides a summed signal to the subwoofer amp, and provides another set of stereo outputs to the main amplifier. In addition, the unit has the capability to bridge the inputs of a dual channel power amplifier to provide sufficient power to the B380 (or B460). The unit is designed for these two systems. I suggest you read the brochure for the systems by following this link:

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

There is also a model BX63A that provides a variable crossover frequency control. Personally I see no great advantage to this model over the BX63. I use a BX63 with my B460.

I hope this is helpful.

Best regards,

Peter M. :)

[Gary C.]

Thank you Peter. :)

[pmakres1]

Gary,
You're very welcome..I hope you can find one of these crossover units. They do turn up on eBay from time to time. The B380 is a very nice sub.

Good luck!

Peter :)

[Mr. Widget]

If you don't run across a BX63 or BX63A, there are quite a few other subwoofer or general purpose crossovers you can use. Any of these will require a dedicated amp for the sub.

What type of system are you using the sub with, HT or two channel stereo? What are the speakers that will be used in conjunction with the sub?

Widget

[Gary C.]

My stereo gear is all Yamaha components from the Golden Years of the 1980's.Just their standard high-end stuff from the time:amps,cd players,cassette decks,turntable,etc.
I'd like to try the sub with each set of speakers I have,just for grins.L112,L150,L250.Probably for a little while at least,have it in use with the L250's,just to see how good that could be.
Maybe long-term use with the L112's,as they could probably benefit the most from the low-end assistance.

Please do tell about other crossover networks that will give acceptable performance.I'd most likely get whatever is available and will work,while keeping my eye out for the proper JBL unit to come along.

Thanks for the help.

Edit:will a JBL 5232 work?

[4313B]

Personally I see no great advantage to this model over the BX63.

The variable low pass of the BX63 can be nice to have as are the 0.001 uF high pass bypass caps. JBL also saw fit to bypass the low pass coupling caps in the BX63A as well. The bypass caps can be added to the older BX63 to improve performance. The BX63A is a tad cleaner sounding. If one has the older BX63 just add the bypass caps and call it a day.

Edit:will a JBL 5232 work?

I wouldn't waste my time with a 5232. The high pass is active and "dirty" compared to the passive high pass in the BX63 or BX63A. Additionally, I don't believe that particular model has the required high pass bump filter. I've posted extensively about these things. Build your own if you're so inclined. Schematics and details can be found with a search. Heck, gut a 5232 chassis and build a BX63 in it!

Further reference - B460 (http://audioheritage.org/vbulletin/showthread.php?t=4557)

[Ian Mackenzie]

The BX is a nice unit and worth the wait if you can.

Apart from what's said already it also has the desired LF boost for the 380 extended alignment as I recall.

And I think its just a 1st order HP filter using series capacitor.

So its does some neato tricks. Subs can be a prick to set up and integrate properly so I would recommed that unit.

I have seen a schematic around and it would not be too unreasonable to build one up sez I.

Ian

Edit: Well we posted at the same time but the points are reinforced.

Good luck and enjoy.

[4313B]

Subs can be a prick to set up and integrate properlyTrue. You might find yourself doing things like stuffing the ports of your L112's to get a potentially better transition.

[Zilch]

B380 wants lotsa power. You're not going to run it successfully without providing it with a dedicated amplifier. See the brochure in the library for factory recommendations. For just messin' around initially, you might play with a car audio sub passive crossover, but you're left with the problem of how to sum the left and right channels to drive it.

The BX63(A) was designed to do all that stuff, and then some. While I have one, I don't use it (not gonna sell it, tho), rather, I just run B380's through a separate amp fed from the subwoofer outputs on my system controller, which are already summed. B380 plays just fine without the added VLF assist provided in BX63(A). See here for more info on that part:

http://www.lansingheritage.org/html/jbl/reference/technical/1983-subs.htm

If you don't have subwoofer outputs, you're going to have to create them using an external line level crossover, and if you're only using one B380, you'll have to sum the left and right channels as well in the process. Best answer there is to buy or build BX63(A), though M552 will do it, and LF cards are available for 523x series electronic crossovers, as well.

Another option is to purchase a subwoofer "Plate" amplifer such as those offered by Parts Express, which have summing and sub crossover built in, plus other features. Their 500 watt version is just under $300, though I think it goes on special from time to time. If you had two B380's, you might get by with a pair of their 240 watt ones for less, instead.

Subs are fun, and a worthy enhancement of most systems. After the initial "rattle everything in the room" phase, you'll settle on using them at moderate, even subtle, levels once you discover that too much bass is, well, "too much." The objective is to extend the bass lower, primarily, not to create unnatural sound....

[Mr. Widget]

Please do tell about other crossover networks that will give acceptable performance.I'd most likely get whatever is available and will work,while keeping my eye out for the proper JBL unit to come along.

Many of us have used a variety of pro active crossovers... unless you buy a really good one, most of them are a disappointment if you are a picky listener.

These two home crossovers are quite good but will cost a few hundred each and are also rare:
Dahlquist LP-1
Symmetry ACS-1

One home/pro possibility that is typically less costly and easier to find is the Crown VFX 2A.

Good luck.

Widget

[JuniorJBL]

I have found my Ashley 1001's to be great crossovers for subs. I do use crown K2's for the amp and that is how I summed the signal when I had one sub.
Just my 2c

[Zilch]

Good point. Some amps have channel summing to mono, as well.

I have a Sony ES sub amp here I smoked doin' that to run a B380. :D

[JuniorJBL]

It seems to me that the easiest way is with a pro amp because they usually have options like this and they are relatively inexpensive compared to good home amps that go in excess of $2500 or more.:)

[JBLnsince1959]

It seems to me that the easiest way is with a pro amp because they usually have options like this and they are relatively inexpensive compared to good home amps that go in excess of $2500 or more.:)



True, but as mentioned above, if you're a picky listener ( and I think one should be for stereo) it may not sound the best. pro actives, specially "new Ones" ( I'm showing my age now) with their 24BD can make the music sound "harder". Of course it's a matter of taste.

[JuniorJBL]

I run my subs crossed very low so I have not found that it makes much difference. But I do have rane and ashley parametrics on these channels as well.
I did have a Proceed HPA2 running my subs for a while and it did work very good but I have since changed back to my K2's because I much prefer the proceeds on the mains. The K2 has a bit more power but does lack the extra bottom end extension that the HPA2 had, but with the parametrics in place that is all but history. Anyways to get an amp that has the power of the K2 and the sound of the Proceed you must spend an insane amount of money:shock:
Shane

[JBLnsince1959]

Anyways to get an amp that has the power of the K2 and the sound of the Proceed you must spend an insane amount of money:shock:
Shane

10-4 ;)

[Mr. Widget]

True, but as mentioned above, if you're a picky listener ( and I think one should be for stereo) it may not sound the best. pro actives, specially "new Ones" ( I'm showing my age now) with their 24BD can make the music sound "harder". Of course it's a matter of taste.

I am not sue if it is indeed the slope or the circuit design, but I agree about the "harder" comment. You could also say harsher, or aggressive.

I too have the Ashley 1001. I like it much more than the Rane, Audioarts, and others I've tried. I haven't done a thorough evaluation of it, but I don't think it is in the same league sonically as the Dahlquist or Symmetry. ANother good on is the Bryston 10B, but it is typically about a grand on the used market.

Widget

[JBLnsince1959]

I am not sue if it is indeed the slope or the circuit design, but I agree about the "harder" comment. You could also say harsher, or aggressive.



Yes, those are good subjective adjectives( I use hard). I think it's both, however, try getting an old active 12DB and see if there's a difference. There is to my ears, the 12DB sounds more "musical" :blink:

[Mr. Widget]

OK, but you really can't make that comparison because the associated electronics are different. You are right that you are comparing different slopes, but you are also comparing different circuit topologies as well.

I have a new crossover that allows me to pick my slopes... 12 doesn't sound inherently more musical than 24 with this device... they certainly sound different and depending on the drivers being used 12 may be preferred, but they sound different as expected due to the different slopes. I have been using the new device at 96dB/octave slopes as this is even better... at least with the drivers and frequencies I am using.

Widget

[sanpablo]

"Best answer there is to buy or build BX63"
And where can i found the plans ?

Thanks

[JBLnsince1959]

I have been using the new device at 96dB/octave slopes as this is even better... at least with the drivers and frequencies I am using.

Widget

what device was this, I must have missed it.

[Mr. Widget]

what device was this, I must have missed it.

Don't ask;) It's an awesome single rack unit that is a bit pricey but a deal when you consider all that it does. I have the balanced preamp version which currently retails for about $4K.

http://www.deqx.com/dsp-product/PDC26P-Preamp.html

Widget

[JBLnsince1959]

Don't ask;) It's an awesome single rack unit that is a bit pricey but a deal when you consider all that it does. I have the balanced preamp version which currently retails for about $4K.

http://www.deqx.com/dsp-product/PDC26P-Preamp.html

Widget

hmmmmmm :hmm: Nice toy.... ;)

[Ian Mackenzie]

When it comes to subs I prefer Kiss (keep it simple stupid).

As mentioned above a plate amp is a fun quick fix and many have a variable FR point and phase to facilitate setup. Mind you we have talked this through before on previous forums...hey Giskard.

The problem with certain crossover topologies is they add considerable group delay and this amongst many room related interactions can make subs a deal to integrate correctly.

The subtractive AllPass crossovers like that below are sometimes deemed better for subs crossing over below 150 hz.

I would tend to avoid an active high pass filter unless you are only using it for ELF on your THX setup as active filters with rare exceptions degrade (1) audio performance.

The BX63 however looks easy enough to build up and as it was purpose designed I would run with that for the 380 sub anyways.

If you are feeling adventurous and like a good read before bedtime the subject of phase coherent crossovers will no doubt appeal. Despite all our knowledge they are not an exact science but this paper explains in simple terms what happens .....By your own audio legend up in the Sierra's CA Nelson Pass.

http://www.passlabs.com/articles.htm


Ian

(1) The Hi End Active Crossover.

PS My Scanner is very feeling ill so spy photo's of this snippet of an article by Kaufman must suffice for now!

[Zilch]

"Best answer there is to buy or build BX63"

And where can i found the plans ?

ThanksUse forum "Search" function to find many threads on BX63(A). Some have pics of ones members have built. Look also for links to the technical manuals, which include the schematics for both versions....

[Robh3606]

Take a look here


http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/UREI-%20BX63A%20ts.pdf

Rob:)