Jbl Sr4719

[lgvenable]

I had a chance to purchase a an excellent condition 4719 dual 18" sub cabinet this weekend at 200. It seems tha originally it had 2241's in it, but I cant find any info at the JBL website. Where can I find the info on it?


In talking to the JBL reconer who had it he uses 2241's in his business, but wouldn't sell any kits unless they were purpose ordered for me, and since the season for shows is upon him, that might mean my cabinet is empty until September.

I currently have a 2245H, and a 2245H basket, and was planning on running the dual sub with 2 AB systems 821's running 600wpc into each side.

from out conversation he was hesitant (or unwilling) to recommend which driver set I should go with. Should I plan on reconing both as 2245's or as 2241's?

Second, the drift of the conversation led me to understand that my (front loaded) L100T system was probably not ideal, and that for a better system, I should consider using horn loaded speakers.

Guys I'm not a sound engineer, I do industrial chemistry on high speed coatings applied to aluminum. Where, other that this website can I find a forum to talk to sound engineers and the like from Harmon (as he said). While I as loaned a book by Yamaha (Sound reinforcement Handbook) >>all the answers are in there.....

I don't mind selling off all the L100T;s and going to another type speaker setup, but was hoping that a pro could in 30 to 45 minutes aim me directly at what I needed so I did not waste a lot of time spinning gears. Now to be told "conquer this book you'll understand all....was disappointing. I got that feeling that since I had professional amps, I should do the speakers like a pro would (he spent his youth designing theaters.

where within JBL pro forums can I go to talk to folks who can aim me right at the info I need to set up a full on theater with custom front loaded horns if that's where I need to go.

Recently I had the opportuniy to have bought a loaf of AB Systems(821's +713's) and BGw (250D) amps, and have like a mix of 15 of these professional amps; now I just want to set up the killer speaker hardware without wasting money where it didnt need to be spent.

[mikebake]

If only it was that easy...............................

[lgvenable]

if only that was answer. I'm looking for direction not esoteric answers. I've already had too many of those this weekend, if you catch my drift.

Besides.... am I wrong in thinking if someone works in sound reinforcement or the design of theaters, that if a paying customer walks in the door you're willing to help??!!

If someone asks me how to coat or apply materials, or build a gravure applied (or 55 other methods) web to web structure, I could give a 15 minutes overview; so I just expected someone who did (sound engineering)it for a living could too.

Larry

[Earl K]

I had a chance to purchase a an excellent condition 4719 dual 18" sub cabinet this weekend at 200. It seems tha originally it had 2241's in it, but I cant find any info at the JBL website. Where can I find the info on it?

- You can find info on the SR series over at JBL Pro .

- SR Series pdfs (http://www.jblproservice.com/NAVIGATION/SR%20Series.html)

>< cheers

[lgvenable]

I had searched and couldn't find the SR series, under which group?
Pro Audio?
Larry

[Earl K]

I currently have a 2245H, and a 2245H basket, and was planning on running the dual sub with 2 AB systems 821's running 600wpc into each side.

from out conversation he was hesitant (or unwilling) to recommend which driver set I should go with. Should I plan on reconing both as 2245's or as 2241's?

- The 2245H can not be reconed as a 2241H. They have different magnetic structures , as well as differences in the top-plate depth .
- Anyways, the 2245 is a better subwoofer .


I had searched and couldn't find the SR series, under which group?

- It is tough to find anything when you go through JBL Pros' "front-door" ( so to speak ). I just did exactly that ( then engaged the search function ) & got mostly garbage in return .
- I find it best to use the direct links that Giskard has provided to us / located at the bottom of this forums' main page .

>< cheers

[Earl K]

where within JBL pro forums can I go to talk to folks who can aim me right at the info I need to set up a full on theater with custom front loaded horns if that's where I need to go.

- I think LHF is mostly focused on 2-channel but; Harman employees will direct serious HT enquiries to their dealer network which sells,
http://jblsynthesis.com/images/syn_logo.gif (http://jblsynthesis.com/default.aspx)http://jblsynthesis.com/images/ENG_sys-the_systems.jpg (http://jblsynthesis.com/products/the_systems.aspx?Language=ENG&Country=US&Region=USA)
- By all accounts it takes some pretty large bags of cash to get their attention .
- Becoming "uber" familiar with the different Synthesis parts ( & series ) will help / since ( according to TiDome) there are some deals to be had out there / but one needs to move quickly sometimes, when deciding whether or not the trigger should be pulled.
- I find it pretty informative just to see what permutations & combinations Harman offers for different sized viewing rooms .

- For those whose budget expectations are created mostly by the tracking of past eBay sales, I'd suggest it's best to see what can be learned by observing someone like Titanium Dome .
- "TiDome" has had a few HT systems of different types and has posted quite a lot of info about them . One can learn a lot by keeping track of what he is up to .


>< cheers :)

[robertbartsch]

Keep the L100T as they are very good.

So the dual cab 18s are both dead?

[lgvenable]

I bought the cabinet, and they had stripped the 2241's out to use in a w bin sub based on a w bin that jbl made for the movie "earthquake".
Larry

[grumpy]

add an "X" to the end of the model # & re-search jblproservice.com,
if you haven't already.

Box size seems on the small end for a pair of 2245H's (~16ft3?) but
might work with retuning (lower) and some EQ (needed anyway).

[lgvenable]

Earl/others
Then, can I use the box wth twin 2245's (as I already have a 2245 basket needing recone), along with the one in this sub, or alternately I just buy 2 x 2241's.

Anyone out there know what putting a pair of 2245's in the 4719 cabinet would do to the port tune on the box? Its the same size as my 12 .04 ft3 box

see attached photo >> DIY designed last year, port tuned to 25HZ
Larry

[grumpy]

guessing a 40Hz tuning of the cabinet (4719), replacing the 2241's with
2245's and not retuning the box models (simply) as the peaked line

[lgvenable]

I tend to agree. Its probably a good book to read, but from what I've seen so far, front loaded speakers suffer a dB loss at 30 ft or so, and in a home theatre, seldom will someone be 30 ft from the speakers.

Horn loaded speakers would seem to be made for larger venues, and from what I've seen are more directional, since they 'aim" all the sonic energy dispersed by the front loaded speaker in a narrower fan shape, enabling the sound to travel further. It also seems that you have to delay the woofer sopund by some small number of milliseconds to allow the bass a, mid and HF to hit you at the same time. (is that correct).

However, tis all started when I told him I had scored a mess of 2446J's (16 ohm) and 2404J or H (8 ohm), and AB Systems 713 mono-troamps to drive them, and was waiting to understand what I could do with those to make a blended tri-amplified system.

Problem was I couldn't keep him on subject, as I guess he's more focused on making bigger $$ from shows than dealing with self made enthusiasts like me.

[lgvenable]

Grumpy
I have a velodyne sms-1, so I should be able to do a parametric EQ manually.
What would I need to do to hit say 25 to 30 HZ
Larry

[grumpy]

changing the port... extend length or (probably more practically) reduce the
port area along it's entire existing length ... -very- roughly by 1/2.

25Hz isn't a bad target (but a bigger box would make this easier).

Then implement a bump filter (peaks a bit at the box/port resonance, then drops
off at lower frequencies... which helps protect the driver). Room gain will
help also, in terms of getting usable response in that region. SMS-1 is nice tool
for this.

If you don't have any modeling tools, you could do worse than
what's available here in online (java) versions as well as for Win/PC:

http://www.linearteam.dk/default.aspx?pageid=isdonline

Nice looking DIY 2245H cab implementation!

[lgvenable]

Thanks!
The cabinet is a box in a box, lined with fir 2x4's The inner cabinet is 3/4" baltic birch, the outer cabinet is walnut veneered plywood, with cross-braces in the center.
I added bracing on the inside to reach 12.04 ft3 internal volume, and two x 14.67 (or 13.67?) 6"ID ports and got 24.79HZ when tested with my woofer tester.
Its got a matching(zilch) jbl navy cloth covered grill (same as the L100T next to it).

Oh...and it weighs 230 lbs.

[lgvenable]

Grumpy
I was selling two 2240's. what about those?
I could just install a second set of terminals and bi amp them, drive each with a 600 wpc amp, and then turn the gain down on the amp till it sounds right (like I did on the 2245 sub).
larry

[grumpy]

"In most applications, the 2241G/H can provide more
low frequency response, 3 dB more output and less
distortion than the 2240G/H, with little or no enclosure
retuning."

Given that (from the 2241 spec sheet), why not try it if you have them?

As a sub, it just appears that tuning is ~3dB less/watt, with similar
extension (30Hz is going to be ~10dB down until you throw the room
into it)... at least this is what the T/S parameters show on a cheap
modeler :)

[grumpy]

an example (making some assumptions about the cabinet) comparing 2240/1/5 cases,
each at 100w input (using WinISDpro this time):

[lgvenable]

Grumpy thanks for that,
Could you send a higher res photo (or screen capture) to my email, lgvenable at gmail dot com. Also include the speaker setup for winisd pro (the files to pick and load the speakers in a new project from from) for the 2240,the 2241,and the 2245. Thanks a bunch in advance!

I got the cabinet re-wired tonight, to use two twistlock speaker connections with 12/4. I'm waiting on the 20 ft piece of 12/4. The amps are already to go, so I'll be running 600 W mono into each 2240H in the cabinet.

The AB amplifiers are much stronger than the BGW's, and look beefier inside as well. I should have it up in couple of days, and I'll post a picture. The two enclosures will basically have amps stacked on them, and eventually amp racks. My wall is starting to look like pretty wild with these two 4' x30" x 24" cabinets...huge!

My 42"Phillips is starting to look pretty small.

and the sound engineer who's gone over all the amps to make sure everything was perfectomundo said, stay with the L100T's as well. He did suggest the addition of a 25 KVA transformer and an isolated ground to bonus room for the theater amps power supply to get rid of all ground loop issues, so that is under way as well...so no more isolation transformers.

Larry

[grumpy]

Could you send a higher res photo (or screen capture)...If I had saved it... Seriously, if you grab WinISDpro and have the JBL Thiele/
Small table, you should be able to pound all this out and more in about 5 minutes.
(OK... maybe add 30 min to learn how to steer :)). If you have
questions after futzing with it, let me know and I can respond to specifics.

"trick" ... when entering parameters for a driver (e.g. one not in the WinISD
library), start with an empty template and let the program calculate what it
can, letting values that are calculated and approximately in-line with the specs
just be close enough. E.g., enter Qms and Qes and let the program calculate Qts.

Vas, Re, Fs, Xmax, Pe, Mms are useful to start with, and are usually available.

For 2240H, I entered:
Qms 2.2
Qes 0.25
Vas 481.4 liters
Fs 30 Hz
Mms 164 g
Le 1.40 mH
fLe 1KHz
Re 6 ohms
Xmax 5.6 mm
Pe 300 w

... and let the rest of the parameter be calculated.

If you enter -all- of the parameters, there will often be conflicts (inconsistent
parameters), and you won't be able to save the new driver file.

I assumed the 4719 was ~16ft3, based on the external measurements and
guessing a bit. 40 Hz was the tuning I assumed for the unmodified
box/port.

[SMKSoundPro]

I just got home from a family funeral in illinois and saw this thread.

Sr4719 = 48"x24"x30"/1728 = 20.0 ft3.

20 cu.ft.

Original factory tuning on go-bys were 40 hz.

My clones were 41hz before adjusting.

I have one 4719 in my shop with 2245's with each driver wired separately to a Yamaha 2200 and driven by a dbx 120xp from 80hz and down.

I did not re-tune the box as it may have to go work with the other 4719's with 2241's. Call me a nut, but with the 2245's, its close enough down there for my workshop stereo rig, and the bartenders come upstairs and bitch about it all of time! i have to keep it way turned down.

[MikeBrewster77]

I just got home from a family funeral in illinois and saw this thread.


My sympathies on your loss.

Sincerely,
- Mike

[lgvenable]

The cabinet still needs a little more touchup, so far one can of resolve spray. But here 's the $200 4719 cabinet find with the NOS 2240's I did have for sale.

Seems like a dead nuts fit, now I have to completely re-do the end of the room, as I already had a 17.6 ft3 2245 sub, and as you pointed out SKS..this dude is 20 ft3.

The two AB Systems amps were scored at the same time as the speakers and are wired to run bridged mono at 600 WPC & 8 ohms into each of the 8 ohm 2240's mounted in the 4719 cabinet. I'm going to get a DBX 260 Driverack to EQ the two cabinets, so these things should shortly be turning up the bass.

What a deal, and now I'm glad all I got was low ball offers for two brand new, but 3 year old 2240's, still in JBL boxes they were sold in.....

Larry

[lgvenable]

I got a Driverack 260 to replace my sms1, and all I can say is "Holy Cow"!!!!!
I have never heard anything so loud as 2 AB amps at 600 wpc mono into each speaker. The vibration from the box cause the L100A's sitting on top to walk .

I can understand a couple of comments I've seen on the forum, as the sound level just drives you back, clear, undistorted, but at an entirely new level. I've got a local sound engineer I'm working with and he had me place both subs toward the rear wall to couple the room, and the effect was unbelievable

:rockon2: