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pfreak
06-30-2003, 08:50 AM
http://www.dvdstore.at/synthesis/s1sbig.jpg

Hello,

I would like to announce gladly the JBL Synthesis 1 Subwoofer copying if plans or other has please. I am very much interested in the interior life of the housing. Are for each answer gratefully


Here still a few technical data

Sorry for my bad English :(

18" THX Subwoofer
Sensitivity ( 2.83V @ 1m ) 95dB
Impedance 8 Ohms Bass Driver 18" Aquaplas cone
Power Rating 800 Watts
Frequency Response 18Hz - 1000Hz
Dimensions ( H x W x D ) 876mm x 533mm x 559mm
Weight 55kg [/b]

4313B
06-30-2003, 09:33 AM
See
http://www.jblpro.com/pub/cinema/4645c.pdf
for Pro version

The Synthesis One Subwoofer originally used the 2245H LF transducer, it now uses the 2242HPL LF transducer as shown in your photo.

pfreak
06-30-2003, 09:46 AM
What ist better now !

Because the 2245 H have a very low frequency (20 HZ). Are you sure that in den Picture is the 2242H ?

4313B
06-30-2003, 09:56 AM
Yes, I am sure the transducers in your picture are 2242's. I am quite familiar with both the 2242 and the 2245.

pfreak
06-30-2003, 10:13 AM
and witch one is better now !!!

2245H

Power Capacity: 600 W
Sensitivity: 95dB SPL, 1W@1m
Frequency Range: 20 Hz to 2 kHz


2242H

Power Capacity: 800 W
Sensitivity: 99dB SPL, 1W@1m
Frequency Range: 25 Hz to 1,6 kHz

4313B
06-30-2003, 11:16 AM
Short answer - 2242H primarily due to it's lower power compression and lower harmonic distortion.

*****

The power capacity of the 2242H in the same terms as the 2245H is 1600W. Pe of the 2245H is 300W, Pe of the 2242H is 800W.
You might want to read this as well http://www.jblpro.com/pub/technote/tn_v1n22.pdf

pfreak
06-30-2003, 11:33 AM
Whatever loudspeakers you would recommend to me thereby I a good and clean bass have where the frequency are correct. You know yourself there better out

4313B
06-30-2003, 11:44 AM
I'm not sure I understand your last post. What are you trying to accomplish? A "better" Synthesis One or 4645C?

pfreak
06-30-2003, 11:54 AM
Actually I want a Synthesis 1. But where is there exactly differentiated

4313B
07-01-2003, 05:46 AM
The Synthesis One currently retails for $2400.
2242H/HPL (originally used the 2245H) in 8.0 cubic foot volume tuned to 30 Hz.
The 4645C currently retails for $1203.
2242H/HPL in 8.0 cubic foot volume tuned to 25 Hz with option to add 25 Hz (Q=2) auxillary filter.
JBL is going to re-tune the Synthesis One in the near future to follow 4645C specifications. http://www.jblpro.com/pub/cinema/4645c.pdf

If you are going to build your own, the specifications to use are 8.0 cubic feet tuned to 25 Hz. Use 1" thick MDF liberally braced. The internal dimensions I personally use are 29-7/8" x 24" x 19-1/4". This puts the lowest internal standing wave at ~ 225 Hz. You can build your enclosure(s) to model the Synthesis One styling. The 2242H retails for $839 and the 2242HPL (no rubber tire on magnet) retails for $803.

MJC
07-01-2003, 08:02 AM
An 18" driver certainly moves a lot of air, but from what I've read elsewhere, smaller transducers can respond quicker. Thus in a move soundtrack that has a series of explosions in a row you will hear the separate explosions with a smaller driver instead of just one massive explosion.
What is your thoughts on this?

Robh3606
07-01-2003, 08:31 AM
"An 18" driver certainly moves a lot of air, but from what I've read elsewhere, smaller transducers can respond quicker. Thus in a move soundtrack that has a series of explosions in a row you will hear the separate explosions with a smaller driver instead of just one massive explosion."

I don't know about that. Giskard just had the calculations up for the force to cone weight ratio for the E145 as an example. I doubt many other drivers can compare to the acceleration that motor and cone mass are capable of. It depends on the individual drivers, motors, cone mass so I don't think you can generalize. Depends on the box tunning too. Lots of variables. I have never used 18's but my 15's and 14's are barely moving so they are well within there linear range even at high SPL's. The bass from them beats the pants off of any 10 or 12 I have ever used. You have to look the distortion too. A 10" drivers is going to be working a lot harder for the same SPL. Basically it all boils down to the most air volume with the lowest distortion, lowest power compression. I think a well designed big driver properly tunned will win in most cases.

Rob:)

boputnam
07-01-2003, 08:41 AM
"...it all boils down to the most air volume with the lowest distortion, lowest power compression. I think a well designed big driver properly tuned will win in most cases."

Hear, hear! I second that, Rob, and can validate it from recent experience with the 2245H's (18-in) - these badboys are astonishingly responsive, tight (punchy where the source material is so) and at the same time full, beyond anything you might expect. You may match (or exceed...?) the response using two 2235H's (15-in) due to combined surface area, but you'd get only close with a one-on-one test.

MJC: "...in a move soundtrack that has a series of explosions in a row you will hear the separate explosions with a smaller driver instead of just one massive explosion."

With a larger format transducer you will not only hear the individual "explosions" (in your example) but you have the added pleasurable experience of having been knocked off your feet! The REAL Reality TV! :D

Go large, high quality, properly tuned.

IMHO!! :p

mikebake
07-01-2003, 10:41 AM
"An 18" driver certainly moves a lot of air, but from what I've read elsewhere, smaller transducers can respond quicker."..."
What is your thoughts on this?"

This is an utter (and common) fallacy, and one that won't go away. It has been discussed ad nauseum on the high efficiency forum at Audio Asylum, and definitively put to rest.

Repeat after me; at a given hz, smaller drivers are not "quicker". There are some possible reasons why people think this, such as
they have heard "mudmotor" drivers with poor control/distortion, etc.

Put this concept out of your mind; it is incorrect.
Remember this, too; we are talking about a volume displacement function, i.e. you can empty a swimming pool faster with a bucket than a teaspoon.
Smaller drivers may have other characteristics (good or bad), but being "quicker" ain't one of them.

The large magnets on JBL woofs and subwoofs, for example, provide great cone control and start, stop, and reverse very well!!!

The dumb (#*^(#@$ that think that some cabinet with a bunch of small drivers is going to combine to make great, deep bass, with additional "speed" are morons...............

But then, ask me how I really feel!!!
HAR!

MBB

boputnam
07-01-2003, 11:41 AM
There was a most interesting post out here earlier - suddenly gone missing - from the inimitable Giskard. The bit I recall the most, was attributed to the 2245H and said (I paraphrase...)

That's what I've always admired about the 2245H - you give it 1 watt, and you Get it All! :D

4313B
07-01-2003, 12:24 PM
Sorry Bo, I deleted the post when I realized I was just hashing over what you and Rob said.

As for the 2245H comment, I think I said -

If I had to chose only one thing I like most about the 2245H it would be that even with as little as 1 watt input, you still "Get it All".

But seriously, I'm back to this post because I want to know how Mike really feels :)

The theory of a smaller driver being "quicker" is valid I suppose. The theory is shot to hell if the smaller driver has a heavier moving mass or a weaker motor. The choice of words might be the error. I understand your point that for any given frequency the smaller driver isn't going to be quicker or faster, 50 Hz is indeed 50 Hz and that's what makes it 50 Hz. But I think you reinforced the common perception of "quickness" with the sentence "The large magnets on JBL woofs and subwoofs, for example, provide great cone control and start, stop, and reverse very well!!!" and probably therein lies the reason why certain transducers are deemed "faster" or "quicker" than others. Attack and decay. Mass and acceleration/deceleration. "Fast" is a term used to describe a transducer like the E145/150-4H. Although I'd put it in the "really fast" category :p

The 4645C is indeed "fast" enough and "quick" enough to render an audio playback of several tightly spaced 105mm artillery hits as intended, instead of as one big burp.

*****

"The dumb (#*^(#@$ that think that some cabinet with a bunch of small drivers is going to combine to make great, deep bass, with additional "speed" are morons..............."

The concept of scaling is valid. Two 4645C's for a real small venue, perhaps a dozen for a big venue. A bank of E145's will be perceived as "faster" or "quicker" than a bank of 2245H's simply because the E145's have such fantastic transient character. Gotta pay the piper though, those E145's simply will not do what the 2245H's can do way down low.

Scaling occurs in transducers themselves as well. An example would be the excellent scaling done with the 2235H and 2245H. JBL increased the electromagnetic force of the 2245H to sufficiently deal with the increased moving mass and compliance resistance in such a way that, in reality, one might be hard pressed to tell the difference between the transient character of a properly loaded 2235H and a properly loaded 2245H.

Now the scaling of the 124/2203 and the 136/2231 is interesting. I remember a conversation with Mark Gander WAY back in the 70's about this driver... Basically a 12" basket and cone with the whole back end of a 136/2231 bolted to it, ROFLOL. (Kinda like slinging a 454 big block into a Vega). But... we're all used to listening to the 124/2203 in a 4315 and the 136/2231 in a 4333. Well that much volume on the 124/2203 "kills" any "speed" or "quickness" advantage is might otherwise have had (same motor as a 136/2231 operating on 50 grams less moving mass). Result was the 4315 didn't really show any "speed" or "quickness" advantage in the bottom end even though it used a smaller driver. Now, pop that little beast into a 1.6 cubic foot space tuned up to 40Hz or so and bang! There comes all that transient advantage back with a rush. Gotta pay the fiddler though. Deep bass then goes bye bye and it is no longer able to maintain the same bandwidth as the 136A/2231A in a 4333 enclosure.

Anyway, maybe I'm all wet. That's just my take on the matter.

mikebake
07-01-2003, 01:55 PM
Yes, scaling is, of course, valid, (and the sound reinforcement concept of coupling,etc.) but my point was the guy who stuffs three 6.5 inch "woofers" in a box, thinks he now has the surface area to perform like one large woofer, and that not only is he equaling the woof but bettering it because the 6.5's are "faster".....

Here are some fun pages for common reference (BTW, I'm not really a Stereophile fan)

Bass terms

http://www.stereophile.com/showarchives.cgi?26:1

and from another archive

"fast: Giving an impression of extremely rapid reaction time, which allows a reproducing system to "keep up with" the signal fed to it. (A "fast woofer" would seem to be an oxymoron, but this usage refers to a woofer tuning that does not boom, make the music sound "slow," obscure musical phrasing, or lead to "one-note bass.") Similar to "taut," but referring to the entire audio-frequency range instead of just the bass. "

From An Audio Glossary by J Gordon Holt

I guess as much as anything, I'm trying to rebut the notion that because a big woofer is big, it must be "slow". That is only ususally true of white football players.

MBB

4313B
07-01-2003, 02:30 PM
Understood :)

There we go! Nice find on the glossary! :)

MJC
07-01-2003, 09:10 PM
[QUOTE]Originally posted by Robh3606
[ The bass from them beats the pants off of any 10 or 12 I have ever used. You have to look the distortion too. A 10" drivers is going to be working a lot harder for the same SPL. Basically it all boils down to the most air volume with the lowest distortion, lowest power compression. I think a well designed big driver properly tunned will win in most cases.



I've got two 12" subs; one is a new 250w JBL PB12 and the other is in an old B212 box, with a new 150w amp and a Peerless driver. And now that I've got them in their correct postions the combo kicks ass. I was watching the movie "Don't say a word" and didn't realize how much bass is in that movie. It was loud, presise and it shook the floor.
Now I do have 3 LE14As that I have been thinking of making into subs, but I don't want to blow out the voice coils, as I did with the 121 in the B212. That was done with the new 150w amp that now drives the Peerless.

4313B
07-01-2003, 09:42 PM
IMO dual 12" subs based on the 4" edgewound copper ribbon voice coil are the bare minimum for HT. I have more than a dozen dual 12" subs in the field based on the 124/2203, most of them powered by GFA-555's, and none have ever blown.

Robh3606
07-01-2003, 09:46 PM
Hello MJC

"I've got two 12" subs; one is a new 250w JBL PB12 and the other is in an old B212 box, with a new 150w amp and a Peerless driver."

Glad you are happy with the set-up.

"And now that I've got them in their correct postions the combo kicks ass."

Yeah placement is really important. Didn't say they weren't good! Just that with what I have used I like the big drivers better.

"Now I do have 3 LE14As that I have been thinking of making into subs, but I don't want to blow out the voice coils, as I did with the 121 in the B212."

I use 2 LE-14A's with the Parts Express 250 Watt plate amps. No problems at all just don't use any EQ on them. They mated with 4655's like glove and kept up no problem. Unless you have a huge space or like bass boost they should work just fine.

MJC
07-02-2003, 12:15 AM
using the LE14a subs might be better, but being I already had the B212 box figured I might as well use it. And I bought the PB12 at about 1/2 the mrp after I blew up the 121a. I had the amp(parts express 150w/8ohm) set to about 50% volume when the 121a got ripped by a huge explosion.:mad:

4313B
07-02-2003, 07:00 AM
If you use two 121A/121H wired in parallel and spaced close together you will double the power capacity and increase the efficiency by 6 dB. This is a substantial improvement. The bandwidth of the B212 is quite remarkable. It has a very heavy cone (162 grams!) coupled to an extremely powerful motor with the result being a free air resonance of ~ 12.5 Hz and a Qts of ~ 0.175. Unfortunately it is over 25 years old and doesn't benefit from newer high temperature adhesives and improved heat sinking so power capacity is limited. Another consideration is that it is mounted in a 2.0 cubic foot sealed enclosure and rolls off at ~ 12 dB/octave instead of 24dB/octave like fourth-order vented enclosures do. Today's DVD's can have quite a bit of information down in the VLF which can overtax a single B212. Used in pairs and quads and coupled to improved amplification instead of the stock E212 Energizer they are extremely effective. AND each 12" only requires 2.0 cubic feet of real estate.

To obtain the same bandwidth from a 2242H would require a 20 cubic foot sealed enclosure but it can be done if you have the real estate :)

Anyway, enough of defending the 121A/H, you would probably be happier using LE14's in vented enclosures. Not as good in the transient department but certainly more efficient and lower distortion per watt input.

jandregg
07-02-2003, 07:44 AM
haven't seen these before, but they fit this thread

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2541493371&category=23794

4313B
07-02-2003, 09:40 AM
We used 4682's as full range SR systems, they are not subs ;) They are pretty weak below 80 to 100 Hz.

Niklas Nord
07-08-2003, 05:58 AM
My friend Neriks on this forum
runs 4 of the JBL 2242H in his
system, and it sounds sweet,
it has details, attack, and no
distorsion that i can hear.

It is SO dynamic that itīs scary,
a really nice setup!

http://www.neriks.com/Images/FrontSpeakers.jpg


It can make the whole house rumble,
i love his system, his dream came true
with this one i think.

:)

neriks
07-08-2003, 03:47 PM
Originally posted by Niklas Nord
My friend Neriks on this forum
runs 4 of the JBL 2242H in his
system, and it sounds sweet,
it has details, attack, and no
distorsion that i can hear.

It is SO dynamic that itīs scary,
a really nice setup!
:)

...



Niklas Nord,

I'm glad you like my system! :) Perhaps we can meet when I visit Stockholm soon?

Niklas Nord
07-09-2003, 02:33 AM
iīl drop ypu a mail