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Niklas Nord
04-29-2003, 04:07 AM
I have been reading the enclosure guide for
the JBL 2245.

Does everyne follow this guide? It doesent
seem to go as low as i want it to go.

What is the ideal design if i want it to be down
to 14 - 16hz

maybe lower the FS of the driver in some way?

CORNER placemement

4313B
04-29-2003, 05:16 AM
You aren't taking into account natural room EQ. Read about it on the Internet. Buy some books. Know the room you're building your system for.

The 2245H doesn't respond real well to corner placement. Use single 2242H's instead if you're planning on doing that. Try sealed first and then ported and see which yields the prefered response.

How do you know it doesn't go as low as you want? You have some previous experience with it?

Perhaps you need to look at running the 2245H in a B6 alignment. Put it in 8.0 to 10.0 cubic feet, tuned to 20 Hz and then apply a 20 Hz auxilary filter with Q of 2.

John
04-30-2003, 08:46 PM
Hi Giskard Is that what JBL did with the B460 Sub and BX63A crossover???

4313B
04-30-2003, 09:01 PM
No, the B460 is a B5 alignment with an auxilary filter at 26 Hz with a Q of 2.

jblwolf
05-06-2003, 02:49 PM
I found this in a old ATTEAN catalog if this helps-WOLF

Niklas Nord
05-09-2003, 01:08 AM
Now i have two 2245 baskets !!

yiiippiiiieieii

Niklas Nord
11-24-2003, 01:25 PM
And there may be 2 more 2245..

Ralf
11-24-2003, 05:14 PM
Originally posted by Niklas Nord
And there may be 2 more 2245..

Where you get FOUR 2245H? In Germany there is no way to get it. :-(

Niklas Nord
11-24-2003, 10:00 PM
'

Whell you can use 2240 and e-155 baskets as well
then recone

Ralf
11-25-2003, 12:04 PM
Originally posted by Niklas Nord
'

Whell you can use 2240 and e-155 baskets as well
then recone

Yea! That`s the way :-)

Niklas Nord
11-25-2003, 01:24 PM
oh yes

There are always several ways you know

Niklas Nord
11-25-2003, 01:26 PM
I learned by Giskard, the jedi knight master of JBL reinforcement

Ralf
11-25-2003, 04:57 PM
Originally posted by Niklas Nord
I learned by Giskard, the jedi knight master of JBL reinforcement

That`s realy right.

Hey Niklas, I have seen 3 2245 and one 2240 on ebay. What is a good price for a recone needed 2245/2240 in EUR?

Niklas Nord
11-26-2003, 06:47 AM
Well, here in sweden they cost cirka 280 euro for a recone
to 2245 ...

EXPENSIVE WARNING

Ralf
12-02-2003, 11:04 AM
Today I found some Informations about enclosures with 2245H. These are from JBL`s "Field Service Manual" from 198x. I got it from a local JBL-Dealer. Next time I will get it to scan it completely...

I'm surprised. That`s nearly the same result as I have calculated here:

Vented Box for 18" (http://audioheritage.csdco.com/vbulletin/showthread.php?s=&threadid=1126&perpage=15&pagenumber=2)

Ralf
12-02-2003, 11:06 AM
and something interesting if you want to have a special frequence...(also 2245)

hificanada
10-23-2009, 08:04 PM
I have been reading the enclosure guide for
the JBL 2245.

Does everyne follow this guide? It doesent
seem to go as low as i want it to go.

What is the ideal design if i want it to be down
to 14 - 16hz

maybe lower the FS of the driver in some way?

CORNER placemement
I had the same problem at first, built right to specs from the audio magazine in around the 1980's. I bump up the lower frequencies with a equalizer. I find the you got to get the equalizer just right, to much and I didn't get the lows I wanted , maybe the room had to much deflection or the amp did not have enought power. I used a coil, 16 quauge that I got free from the JBL rebuilder ten years later, when it needed to be reconed, it helped a bit, got rid of some more highs.
I heard if you put a cap across the speaker terminals helps to get a tighter sound. The size cap, I am still trying to find out.

robertbartsch
10-24-2009, 12:11 AM
I have a few 18" sub bass systems - mostly in 10cf boxes.

Are you building the 14hz subs for your dog freinds?

I always thought the human ear can only hear frequences down to about 25hz. In addition, the music content in CDs and cinema DVDs doesn;t go below this anyway; right?

If I had a pair of dead 2245 baskets, I would see if you could recone them into 2240s since their sensativity is alot higher. some others here probably disagree, however.

hificanada
10-24-2009, 02:02 AM
I have a few 18" sub bass systems - mostly in 10cf boxes.

Are you building the 14hz subs for your dog freinds?

I always thought the human ear can only hear frequences down to about 25hz. In addition, the music content in CDs and cinema DVDs doesn;t go below this anyway; right?

If I had a pair of dead 2245 baskets, I would see if you could recone them into 2240s since their sensativity is alot higher. some others here probably disagree, however.

Yes , 25hz is about right, but symphony's and especially the big Euroupean and U.S pipe organs on the 32ft stop , the lowest note on the 32ft stop is right on the farest left on the pedal, note C produces 15hz.
What they found with pipe organs already way back in the late 1600's is that even when one can not hear it, it still adds harmonics with the higher octive notes C, creating a more powerful sound. This worked so well that a few pipe organs and only a few even has the 64 ft stop.
The 2245H will do some of that also, one can feel the extreme lows that it can make, also adding to the higher octive notes in your system.
I don't recone, but want to learn that, I read that the 2245H has a special ring mounted on the voice coil to keep down problems with harmonics, that the large diaphram can make.
Added picture of the 64ft stop, the sleaves on the top of the pipe slides, if it is put up higher the lower the note will go , more internal Cubic ft, same with the sub enclosure's, al though once built , it can't be changed . So there is a place and reason for the extreme lows, one can't hear.

robertbartsch
10-30-2009, 10:13 AM
I have a couple of 2245s that have been professionally reconed from 2240 cores. Also a single 2242 powered sub that is even better.

JBL OEM recone kits can only be purchased by authorized dealers, so don't expect to buy a kit and learn to recone for fun.

I thought many passive electronic crossovers and music mixes of CDs, movies etc. eliminated most signals below 25hz, in part, to minimize potential damage from ULF excursion.

Is this sub for sound reinforcement, HT or some other purpose?

lgvenable
10-30-2009, 10:32 PM
I made my own, based on a 12 cu ft internal cabinet, two layers of box layer 1 = mdf, outside layer was walnut covered plywood. weighs a ton, 228 lbs; so I dont move it as much as slide it.

Thanks for those pads they sell to let things float on....

FYI it was designed to mimic the look of my L100T's thr navy grlll is not on

47" tall, 31 " wide 24" deep
the upper AB systems amps drvies it 60W biamped cintinuous......load with lots of driving bass.
my exovr is aDbx driverack 260 to conrtrol all inputs parametrically

Doc Mark
10-31-2009, 07:58 AM
Good Morning,

Very nice job, Sir! I'll bet that sub can "do the deed", without even breathing hard!! Thanks for sharing it with us, and congrats on a job well done! Take care, and God Bless!

Every Good Wish,
Doc

robertbartsch
11-03-2009, 01:55 PM
...looks a lot like one of my powered subs only this one is loaded with a 2242. My cab, however is designed so the woofer is firing down at the floor. The baffle is 10" above the floor.

I got the design idea from a cheapie contemporary powered Klip-horn sub.

This baby ROCKS the house foundation on my HT. It is powered with a 500 watt plate amp. When an earthquate, tornado, thunder storm, frieght train, or other impressive sound comes along in the movie you are tricked into believing it is real.

The dogs go NUTS!

lgvenable
11-03-2009, 03:57 PM
Hey Doc good to hear from you:

Yes, and I used one of the 2245's from the same set of speakers as the one you got.

600W continuous creates earthshaking effects on movies. Combine it with this second sub I have, which is two 2240's again controlled parametrically using a dBX Driverack 260; and each speaker driven 600W by its own AB Systems 821 amp bridged mono; well you get my drift...

the 2245 sub does 25 Hz
the SR4719 w/2240H's is good for 30 Hz

So when 1 sub @ 600W is quite enough...do 3@600W continuous; and the effects from a movie are as good as anything I've ever heard at a high $$ venue.

Thank God for an understanding wife. She thinks I'm a bit of an audio nut anyway.

BTW the 4719 box was a find here in Evansville at a cost of $200 for the cabinet.

Larry

hificanada
11-06-2009, 03:09 PM
:)Believe me, there is no other sub like it, I'll sure miss mine if it were gone, shakes the house with not to much effort, I power it with the Inter-M, 10.5 @ 350 watts RMS per channel. I built mine in 1983, probally one of the first in my area.

JBL 4645
06-14-2010, 10:09 AM
I learned by Giskard, the jedi knight master of JBL reinforcement

Well JBL is also…Jedi Blaster Lightsabers.:D


Today I found some Informations about enclosures with 2245H. These are from JBL`s "Field Service Manual" from 198x. I got it from a local JBL-Dealer. Next time I will get it to scan it completely...

I'm surprised. That`s nearly the same result as I have calculated here:

Vented Box for 18" (http://audioheritage.csdco.com/vbulletin/showthread.php?s=&threadid=1126&perpage=15&pagenumber=2)
http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=1374&stc=1&d=1070391898



Hey I like the idea of that tried drainage piping with bends and extended tubing attached to the my diy JBL 4645 a few years back. I wasn't sure if it worked because I didn't have decent way of seeing the frequency response on a recorded graph.

Any idea on the diameter of the tube I see 22" but what is the port diameter?


I have a few 18" sub bass systems - mostly in 10cf boxes.

Are you building the 14hz subs for your dog freinds?

I always thought the human ear can only hear frequences down to about 25hz. In addition, the music content in CDs and cinema DVDs doesn;t go below this anyway; right?


Well cats are limited to 40Hz to 90 KHz