2245 up to 300hz?

[pos]

Hello all,

This is my first post on this forum, though I've been reading it for some time now.
I have a question regarding the low end of the 4345.
I read that it was not a good idea to get a 18" up to 300hz, and that the 2245 was tuned to high in the 4345.
Does that means that a 4345 is less accurate in the 100-300 zone than a 4344? Even bi-amplified?
Would a 4344+sub (2245 or maybe W15GTI) sound better than a 4345?
I'm asking this question because I have the project of building a studio monitor style speaker, with something like 2245+2123+2426/2342, with an horizontal arrangement similar to a 4412.
This could be called a 4444 or 4445 I guess...
I know that the 2123 will not go as low as a 2122 (it is crossed at 340hz in the 4344mk2), so maybe it would be better to use a 2235 instead of a 2245 and cross it around 500hz? Or a 2226+2245 ?...
The only drivers I already bought for this project are the two 2123, so all other options are still open and your input would be more than welcome!

[speakerdave]

Good question, pos, welcome to the forum. I think the problem you are puzzling over should be recognized as signifying that in designing and building a speaker compromises are necessary. It becomes a question of which ones you insist on designing out of your speaker and which ones you will settle for.

If you want to build a speaker like the 4345 the EASIEST thing to do would be to copy the 4345 EXACTLY, even though it would mean back-tracking and replacing your 2123's with 2122's.

You did not say who wrote what you read about not using an 18" woofer up to 300 cycles. Maybe you should just ignore him. Really, the only way you can answer the doubt it has raised is to hear for yourself a pair of 4345's (that have been biamped).

I think you should study Drew Daniels's system which is described here on the Lansing website. It is one solution to the problem you describe. Also, use our search engine in the forums and try to find a description of Robert H's system. Both of these systems use a 15" in the frequency region you are talking about, with a subwoofer below and a ten-inch above.

One option you did not mention is to consider the bass layout of the 4435 and Everest II. The 2234's used on the 4435 are still available new from JBL Pro.

David

Drew's Clues: http://www.audioheritage.org/html/pe...rews-clues.htm

[pos]

Thanks!

Here are the quotes about the 18" at 300hz:
http://www.audioheritage.org/vbullet...3&postcount=19
http://www.audioheritage.org/vbullet...4&postcount=20

And I remember Giskard said something like he didn't liked the tune frequency of the 4345 (too high) but I cannot find where. (maybe I misunderstood, which is quite possible).
I also read Greg Timber's post in the 4345 club thread. He said that the 2245 was a great driver when used as a sub for VLF, but quite difficult to drive (biamp mendatory) and not so articulated (compared to a LE14) when used as a LF tranducer.
In fact the 4345 is the only model that uses it that way.
I never had the chance to listen to a 434X, so I really wonder how a 4345 and a 4344 compare in the low end (not VLF). Everything I have read tend to prove that the 4345 performs better in practice.

You are probably rigth about the dual 15" approach. It was used in most modern JBL monitors (4435, DMS-1, new everest...), so it should be the best design.
But 2245s are easier to find than 2235, because they where also used in PA.
Maybe I could find a 2225 and have it reconed though, but then I would have to find 4 of them!

And, well, I would really love to have something like a giant 4412 !
Just imagine the beast that would be!

[remusr]

Would there be material difference in transients with an 18" or a 15" up to the 300Hz range? The 2245 has a larger & heavier cone than the 2235 with a larger magnet assembly than the 2235 to control it. Different specifics in suspension and magnet structure so lots of variables but they share a similar design philosophy in SFG w/ Flux Stab Ring etc and designed response range down to 20Hz.
The JBL brochures' freq response curves show the 2245 staying flat to 40Hz and -15dB at 20Hz (10ft3 box tuned to 30Hz) with a 2235 flat to 50Hz and -15dB at 20Hz (5 ft3 box tuned to 30Hz) so the 2245 may have some advantage in low bass.
For reference, and you may want to consider buying one of their kits, Gold Sound www.goldsound.net runs the 15" higher in their kits (2235 in 6 ft3 Kit#11 w/ 300Hz XO to 8" 2118H, 2245 in 12 ft3 Kit #14 w/ 80Hz XO to 12" 2206H).
I would say that the 2245 sounds great in my 4345 running passive (not biamp) crossing over at ~300Hz. It is far superior to the 2235 as used in my 4430's in the low bass and its overall articulation of bass instruments is also better. The sound is obviously influenced by room effects, enclosure, crossover & interaction with the speaker it crosses over to. Both have been placed in the same room location as well as many others. In the 443x series the 2235 is asked to go to 1000Hz where it is not the optimum driver - don't know if that affects its low bass performance significantly. So far as dual LF drivers in JBL systems I have only heard my 4435's. I really do like their low end as well, using 2234's, but find it not as quick or articulate as the 4345. The 4435 also does not image very well in my room, a small part of which may be due to dual speakers in the low bass. Neither system is currently biamped, but are using a good Mac MC352 power amp, and maybe that situation would change everything.
Roy

[Zilch]

The 4435 also does not image very well in my room, a small part of which may be due to dual speakers in the low bass.

Extremely small, I'd say, considering the frequencies at which the second woofer operates.

That's not "imaging" territory, in my experience....

[Robh3606]

Hello pos

Welcome to the site.

Does that means that a 4345 is less accurate in the 100-300 zone than a 4344? Even bi-amplified? Would a 4344+sub (2245 or maybe W15GTI) sound better than a 4345?

I have 4344 wanabees. They are biamped with a JBL DX-1 active crossover. With room gain they simply don't need a sub at least not in my room. Run active the 2235 sounds just fine. I can't say anything about a 2245/2235 comparison as I have never done one.

I'm asking this question because I have the project of building a studio monitor style speaker, with something like 2245+2123+2426/2342, with an horizontal arrangement similar to a 4412.

That is similar to my active set-up which I ran for a couple of years without changes. I used an E-145 as my 300Hz and lower driver with subs under them. I also used the 2344 horn as opposed to the 2342. It was a fun system and the 2123 is a very nice midrange driver. I still run the subs, E145 and 2123 but the top end has changed to a 2435 on a PTH1010 waveguide. You have to post some pictures for us. Are you going to run this active???

Rob

[Ian Mackenzie]

Pos,

Why not build a quasi 4344 with twin 2235/2234 woofers. You are going to have trouble finding the 2122H mid cone. The 2123 is more common.

The more recent JBL woofers used in the consumer series 2 way systems with a newer compression driver may be more hifi and better if you want a easier amplifier load.

I dont want to get into discussing the in's and outs of the 4345 tuning on the public forums but are happy to send a pm. Un fortunately there is a lot of mis information about these details as you have read in the links about.

However, one of the problems with the larger 18 inch woofer is it need a larger box to really work properly. The large cone also does a nice job a coupling to the room boundaries hence we ready about technically deficient applications in the 100-300 region..

The 18 inch woofer however does move more air and is has more linearity.

If you want to use the 18 inch woofer you must get it off the floor or use an equaliser to smooth the response. With such a large box this is not alway practical!

JBL typically used an 8 cu ft - 10 cu ft box for the 2245.

In one diy project I personally used the 2245 in a 10 cu ft box (net volume) properly tuned to 27.2 hz. In that system I used an Audax 8 inch mid cone HT210. I suggest you biamp

Later I decided to use the 2344 horn and it works very well. Using the 2344 bi radial is a more open sounding but you must have a room with not many flat bare walls otheruse it will not image correctly.

Depending on the room you can vary the tuning +-2 hz and get a satisfactory result.

You will need to trial a few options. I suggets you make up some test boxes (un finished timber) and see what works best in your situation.

[soundboy]

...I have the project of building a studio monitor style speaker, with something like 2245+2123+2426/2342, with an horizontal arrangement similar to a 4412.

The only drivers I already bought for this project are the two 2123, so all other options are still open and your input would be more than welcome!

Not to be redundant, but what are the design goals? Maximum efficency and output, or maximum transparency, articulation, and detail?

For maximum output, I would go with a 2241/2242 to 300hz. For maximum articulation, and would go with a 12" or LE14 to 300 hz, and use a 2245 below 80hz. How low does it have to go? How many cabs do you want?

Like it has been said, it is all a trade off...the 2241's would play a lot louder, and still get 35 hz or so, in a single cab arrangement, and, they would be punchier in the midbass than a 2245H....
I tried the 2245H's for live SR years ago, and they just don't get it above 100hz, like a 2240, or 2241 did, in my experience...not enough efficiency and punch...they were in 10 cu ft, tuned to 30 hertz, I think. Again, this was for live sound..
JBL used the 2241 and 2123 crossed at 600hz for a PA cab years ago (4738?)....they sounded killer for stage monitors....but I never put a pair in my living room, and listened....maybe that's a good thing???
My 2245H subs in two different systems sound killer below 80hz in my home...nothing better, IMHO. One is below 4408's, the other below a Dynaudio 3 way with 10" midbass....they both blend superbly....not slow or boomy at all...in fact, they both sounded even better after I re screwed the sheetrock to the studs behind each one....the nails had loosened and were out an 1/8" from the walls

[speakerdave]

Here are the quotes about the 18" at 300hz:
http://www.audioheritage.org/vbullet...3&postcount=19
http://www.audioheritage.org/vbullet...4&postcount=20

Oh, those guys!

And I remember Giskard said something like he didn't liked the tune frequency of the 4345 (too high) but I cannot find where.

I'm guessing that Giskard was talking about the box size being too small and the port tuning too high to make the most of the 2245's bass capabilities. Greg Timbers said the same thing.

But that is a perfect example of the kind of compromise I was talking about. The 2245 in a smaller-than-optimum 9.5 cu. ft. cabinet would take away some of the bass but would help the woofer in the upper part of its range. If you put the woofer in a larger enclosure, yes, you would want to cross out of it lower in the upper bass, as soundboy has said. But much lower and you will not be able to use any of the purpose-built 10" midranges in the way they are used in the large four-way monitors, because you would need to make a larger dog box, maybe even a ported one, and that would compromise performance in the upper part of IT's range due to increase in size of the dog box and greater excursions in the lower part of its range. So, you would need to identify a driver to use in the upper bass, lower midrange. The 12" 2202 would present the same problems as the 10's. If you choose a 15", then you must lower your crossover to the treble horn, which would require a different horn, maybe a 2" compression driver. And on and on.

You are probably rigth about the dual 15" approach. It was used in most modern JBL monitors (4435, DMS-1, new everest...), so it should be the best design.
But 2245s are easier to find than 2235, because they where also used in PA.
Maybe I could find a 2225 and have it reconed though, but then I would have to find 4 of them!

Yes--it's going to pay to observe JBL's latest thinking. By the way, if you choose to follow the example of the 4435, it's 2234's you want, not 2235's. If you have frames reconed for the purpose, it's a simple matter of leaving out the mass ring of the the 2235 kit.

Or, you could get some 1500Al's. I believe they are slightly easier to get in Europe than here.

David

[Zilch]

I stay out of 43xx discussions, 'cause I don't do them.

But I'm not above pushing the envelope ahead 30 years or so:

http://audioheritage.org/vbulletin/s...4&postcount=24

[Send Mr. Widget over here.... ]

[Ian Mackenzie]

Pos,

It might be worth looking for an LE14H.

It does not need a big box and does many things very well according to the JBL folks.

Ian

[pos]

Would there be material difference in transients with an 18" or a 15" up to the 300Hz range? The 2245 has a larger & heavier cone than the 2235 with a larger magnet assembly than the 2235 to control it. Different specifics in suspension and magnet structure so lots of variables but they share a similar design philosophy in SFG w/ Flux Stab Ring etc and designed response range down to 20Hz.
The JBL brochures' freq response curves show the 2245 staying flat to 40Hz and -15dB at 20Hz (10ft3 box tuned to 30Hz) with a 2235 flat to 50Hz and -15dB at 20Hz (5 ft3 box tuned to 30Hz) so the 2245 may have some advantage in low bass.

Ok, so maybe the 2245H used that way is not optimum in the sense it will not go as low as it could in a properly tuned enclosure, but will not be more colored in le LF than a 2235.

[pos]

That is similar to my active set-up which I ran for a couple of years without changes. I used an E-145 as my 300Hz and lower driver with subs under them. I also used the 2344 horn as opposed to the 2342. It was a fun system and the 2123 is a very nice midrange driver. I still run the subs, E145 and 2123 but the top end has changed to a 2435 on a PTH1010 waveguide. You have to post some pictures for us. Are you going to run this active???

That is a very impressive system you have here!
I will have some questions about the top end also, maybe in another thread.

Yes I want to run everything active, using a DCX2496 that I plan to buy. The DCX has 6 outputs, which is parlty why I want to stick to a 3-way design.
It is surely not the best device, but if the DMS-1 did sound good with their old digital crossover then it cannot be that bad.
The digital crossover will allow me to put delays on each transducter, and also to play with crossover frequencies. It also has some nice parametrical eq, which could be sufficient to flatten the horn response.
I do not have any picture to post yet. The only things I build so far are two little 14L sealed boxes for the 2123. I put them on top of my 4425 and did some testing, removing the 300-1200 zone from the 4425 and feeding it to a separate amplifier for the 2123 using my PC soundcard.
It does not sound really good, mainly because of the passive crossover in the 4425 that is already operating in the 1200 range. Maybe I should try 1500 or even higher to minimize this.
The ideal would be to test on a 4430, but I don't have any.

[pos]

However, one of the problems with the larger 18 inch woofer is it need a larger box to really work properly. The large cone also does a nice job a coupling to the room boundaries hence we ready about technically deficient applications in the 100-300 region..

The 18 inch woofer however does move more air and is has more linearity.

If you want to use the 18 inch woofer you must get it off the floor or use an equaliser to smooth the response. With such a large box this is not alway practical!

JBL typically used an 8 cu ft - 10 cu ft box for the 2245.

In one diy project I personally used the 2245 in a 10 cu ft box (net volume) properly tuned to 27.2 hz. In that system I used an Audax 8 inch mid cone HT210. I suggest you biamp

Later I decided to use the 2344 horn and it works very well. Using the 2344 bi radial is a more open sounding but you must have a room with not many flat bare walls otheruse it will not image correctly.

Depending on the room you can vary the tuning +-2 hz and get a satisfactory result.

You will need to trial a few options. I suggets you make up some test boxes (un finished timber) and see what works best in your situation.

The DCX with allow me to do a lot of trial and error testing I suppose.
The speaker will *have* to be off the floor because it will have a horizontal layout, à la 4412. I will also have to find/make some nice stands...

It might be worth looking for an LE14H.
It does not need a big box and does many things very well according to the JBL folks

The idea of a not-so-big box is appealing!

[pos]

I'm guessing that Giskard was talking about the box size being too small and the port tuning too high to make the most of the 2245's bass capabilities. Greg Timbers said the same thing.

Yes, I understand now. So that does not mean a 2245 will not perform as good as a 2235 is this situation. It will just not perform as good as it could have. That is fine for me.

Or, you could get some 1500Al's. I believe they are slightly easier to get in Europe than here.

Not sure I will be able to find this in France. Maybe in Germany?
But I guess this will be quite expensive.