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EQ settings for JBL B460

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Wound up workin' at a gas station....
Any suggestions for setting the parametric EQ on my subwoofer amp to mimic the boost normally provided by the BX63/BX63A? I have the B460 and BX63/BX63A spec sheets but they offer little or no help. There is an illegible graph in the scanned copy of the owner's manual that probably details the boost function and tells me what I need to know.

main XO = 60 Hz (controlled by AVR)

EQ adjustments on amp

frequency 18 to 80 Hz (try 20-24?)

bandwidth 0.1 to 1.0 (try 0.5?)

level -1.5 to +6 db (try +3?)
 
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The link Here has what you are looking for. Towards the end of the text it describes the EQ as centered on 26Hz, falling off at 12dB/octave in either direction.
 
OK, that takes care of where to put the bump. Now for the width and height...

Bandwidth? Does that mean what fraction of an octave the boost covers? I suppose I should dig up the amp owner's manual and RTFM.
 
I think it is +6db at 20hz with a q of about 1-1.2.

If you look up the pro box with the 2245 (45XX) in it I recall them saying wht the boost was to get to flat 30hz.

On my 2242's I do an 8db boost at 20 hz with a Q of 1.2. Sounds very good down here!!:D
 
Hey fellas, I've suddenly found myself in possession of a couple B380's--but BX63/BX63A is buried in storage somewhere. Any suggestion what I could use instead?
 
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wiredbecker said:
Hey fellas, I've suddenly found myself in possession of a couple B360's--but BX63/BX63A is buried in storage somewhere. Any suggestion what I could use instead?
Click to expand...

There were B380s (15" JBL 2235H in 4 cu ft) and B460s (18" JBL 2245H in 8 cu ft). Both were tuned to 24-26 Hz and, as stated previously, use +6dB boost at that frequency. W. J. J. Hoge described this configuration in detail in an article for Audio Magazine called "Switched on Bass" circa 1980. You can use any underdamped second-order high-pass filter (Sallen-Key, for example) centered at 26Hz with Q ~2 to achieve this.

Incidentally the Sumo Sampson subwoofer was essentially a B380... so if you can find the accompanying Sumo Delilah crossover, you get the correct EQ.
 
Thanks Wildcataz, I meant B380's. I'm just kind of underwater projectwise. If I can get the subs out of the garage then that frees up some workspace to build again. Until then I'm dead in the water.
 
Holy crap...I started that thread 8 years ago...I guess the internet never forgets.
 
I know this is an old thread, but I plan on doing a mix of

FMOD Crossover Pair 70 Hz Low Pass

and a sub amp where I can set the frequency.

My main goal is to be able to test the Sub to make sure it works properly while I decide what the heck to do with it.
 
If you're already low-passing the response at 60Hz via the AVR, or using something like an F-Mod for the same purpose- this circuit would work to provide the boost/low cut filter of the BX63A (26Hz, second order highpass with a boost of 6dB, which is a Q value of 2). This is built with a standard op-amp (TL072, etc):

jbl_bx63_boost_filter_equivalent.jpg


jbl_bx63_boost_filter_equivalent_response.jpg
That was calculated here:


Regards,
Gordon.
 
Boosting bass to any speaker can be dangerous exceeding the design capabilities of the driver in question. However if you know the RMS capability of the driver in its enclosure design at the frequencies in question and you stay significantly below that rating you should be good to go. A driver rated at 100 watts RMS may be only rated at 30 watts at 25 hz, so as long as you stay below 15 watts at that frequency for instance. Seems like you are giving up clost to 8 db of dynamic range. But its cheaper than loosing a woofer that may not be able to be rebuilt or has has been discontinued for a long period of time. Tweeters until the late 80's and 90's were more often than not very fragile.
 
The JBL 2245 will handle up to 600w electrical power.

And, it has an X-max of 9.5mm.

IME, when tuned properly- the 2245 will easily handle in excess of 300W, even at 26Hz. I have, in fact, built subwoofer using this driver, in an 8 cubic foot enclosure (same as the B460), that could literally make a large plate glass window bow in and out 1/4" in each direction, driven at high output on a 24Hz tone.

And, it's no problem to rebuild (or build from scratch, in fact, using a 2240 or other similar frame) a 2245H. Plenty of good aftermarket parts available, which will match original performance.

Regards,
Gordon.
 
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