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johnaec
03-19-2004, 09:19 AM
'Any idea on how the 2445J driver would sound for midrange, assuming Sub1500 LF, 10" 2012H mid-bass, and 2404H or 2405H for HF? Is 2" a little big for this? 'Any good horns to go with the 2445? I was thinking maybe 2380A or 2382A, but have also heard many don't think this type of JBL horn works well for most music, even though the specs look pretty good.

'Still in search of the most appropriate midrange for the above combination of components...'would still like to hear more about the 2430H...(availability?).

John

4313B
03-19-2004, 09:31 AM
Just a reminder that the 1500 SUB / REVEL 15 driver is dragging around a 300+ gram moving mass which works out quite well in the VLF. If you like the way it sounds operating up into the few hundred cycles range then that's fine, but something with a wee bit less moving mass will probably perform quite a bit better. ;)

"Is 2" a little big for this?"

No

maxwedge
03-19-2004, 09:45 AM
John, your system's growing.:thmbsup:
I like my 2445's/2380's and I don't even have an UHF, yet. But maybe I haven't heard a good 2441 yet (or a upgrade to 2450's:window: )

boputnam
03-19-2004, 09:47 AM
So, could you use something akin to the 2202HJ and lower the crossover point between the VLF and the MF? Or, do you really need something beefier in the LF, like a 2231H...?

Widget and I have been going 'round about this scheme... :spin:

4313B
03-19-2004, 10:09 AM
"So, could you use something akin to the 2202HJ and lower the crossover point between the VLF and the MF?"

I don't recall the 2202 being able to go low enough, maybe if you port it though... the 112/2108 and 2122 work fine in 0.4 and 0.5 cubic foot sealed volumes. I think the 2012 might work if you port it.

"Or, do you really need something beefier in the LF, like a 2231H...? "

2234H? E145? 1400Nd?

johnaec
03-19-2004, 10:14 AM
Originally posted by Giskard
Just a reminder that the 1500 SUB / REVEL 15 driver is dragging around a 300+ gram moving mass which works out quite well in the VLF. If you like the way it sounds operating up into the few hundred cycles range then that's fine, but something with a wee bit less moving mass will probably perform quite a bit better. ;)Yeah - I was thinking of a little sub-cabinet, probably ported for a crossover in the 100-120hz range.

John

4313B
03-19-2004, 10:21 AM
Yeah, that could work. You'll probably have to go active since the upper hump would probably play hell with any passive filter.

johnaec
03-19-2004, 10:43 AM
Active has always been part of my plan, except for possibly the 2404/5H.

John

Chas
03-19-2004, 11:38 AM
Sounds kind of like what I want to do. I am thinking of a fourth order triamp scheme: SUB1500 to about 80Hz, then run my 2231A's at 80-800Hz (or maybe 1K if I install my 2307 horns). Then leave the 2420/2405 passive.

My only concern is that running the 2231A up to 1KHz doesn't seem to be recommended. But maybe using 24 db/octave xovers, it may be okay, since it will attenuate the 2231A a lot more rapidly. Anyone have any thoughts/experience they'd like to share?
Charles.

GordonW
03-19-2004, 02:13 PM
Can't a new 2020 (the 12" version of the 2012) make it down to 100 Hz? I thought I remembered, those things having quite a bit lower f3 in a sealed box, than the earlier generation stuff (2202, 2123, 2118, etc). If so, that might work better. With a 2" driver on the mids, I'd think the 12" should be a pretty nice alternative, crossover points should work out fine up top...

Regards,
Gordon.

johnaec
03-19-2004, 07:30 PM
Originally posted by maxwedge
I like my 2445's/2380's and I don't even have an UHF, yet. What else are you running with these? LF? Crossovers? If you can ever spare the time sometime, I'd really like to hear these in a real-world situation.

John

Mike Bates
03-19-2004, 08:30 PM
I like the horn loaded 2123 with the 2440 and 2405. 180 hz tractix round horn for the 2123 250-1k, then 360 hz round tractrix 1k to 10k with the 2440 and the slots for the top. Also use 2220A's 50-250 in sand filled 60 cycle dipolar expo horns below the 2123's and 3 18" hornloaded subs for the bottom.

IMO the big format compression drivers beg to be used in a fully horn loaded rig. Just using a 10 mid and a 15 bass direct radiator probably would be better suited for a 1" driver and no super tweeter. Plus it will take up less space and be a heck of a lot easier to integrate into your room.

maxwedge
03-19-2004, 10:11 PM
Originally posted by johnaec
What else are you running with these? LF? Crossovers? If you can ever spare the time sometime, I'd really like to hear these in a real-world situation.

John
You could probably skip a stone acrross San Pablo bay and hit my back window!:wave: Yeah come on over, I have tons of spare time.

My system is : 2242 LF, 2202 mid and 2245/2380 hi. I could really improve it with an UHF, but unfortunately they arn't in the budget for some time. I add some eq above 12K and it sounds nicer. I think in my case the thing to do is to snag some 2440 diaphragms and a pair of 2405's, but I have to wait.

I have a pair sub1500's also that will run under 80hz in 2-15 sealed box of about 4 cu ft. I chose sealed cause I don't like the looks of group delay I see in BB6P, so I'm going to try Giskards suggestion to cut with eq between maybe 50-80hz to even it out and then crank 'um up to match the rest of my stuff.

I heard Mr Widget's sub1500's today and they do sound nice in 5cu ft and ported box's (ea spk=5 cu ft) but I just don't have anymore room for big box's.

My whole system is run by a Mackie 1604VLZ pro board Rane 22b/23b crossovers and Hafler amps.

You've seen this (http://audioheritage.csdco.com/vbulletin/showthread.php?s=&threadid=1790&perpage=15&pagenumber=12)...look for my post.

Scott

4313B
03-20-2004, 01:23 AM
"I have a pair sub1500's also that will run under 80hz in 2-15 sealed box of about 4 cu ft. I chose sealed cause I don't like the looks of group delay I see in BB6P"

Just a reminder that any EQ added also affects group delay.

Here's a shot of the group delay properties of the JBL BX-63, a bit extreme for EQ on a 1500 SUB but it does show the effects. I would guesstimate any EQ desired/required for a 1500 SUB in a small sealed volume would come out about the same as porting. In other words, a ported 5 cu ft 1500 SUB system probably has no worse group delay than a 2 cu ft sealed 1500 SUB system using a dash of EQ.

edit

johnaec
03-20-2004, 06:42 AM
Originally posted by maxwedge
You could probably skip a stone acrross San Pablo bay and hit my back window!:wave: Yeah come on over, I have tons of spare time.

You've seen this...look for my post.Ahh...now I remember. I'll drop you a line.

John

Ian Mackenzie
03-20-2004, 07:13 AM
Giskard,

Are you able to simulate the effects of room gain with the un equalised sealed enclosure?

As a guess I was figuring with 12 db rolloff of a typical sealed box the effect of room gain could be adjusted by placement to give optimum extension without the group delay.

Ian

4313B
03-20-2004, 08:25 AM
"As a guess I was figuring with 12 db rolloff of a typical sealed box the effect of room gain could be adjusted by placement to give optimum extension without the group delay."

Yes, I've mentioned numerous times about using room gain to effect and the sealed system is a "natural" due to it's shallow rolloff. I've mentioned boundary reinforcement, corner loading, 2 pi and 4 pi environments, etc. I've mentioned how 2245H vented systems don't necessarily need a whole lot of boundary reinforcement and how 2242H vented systems can use boundary reinforcement to great effect, etc., etc., etc.

One of the biggest problems with selling the old three-piece L212 (http://lansingheritage.org/html/jbl/specs/home-speakers/1977-l212.htm) system was in getting it set up correctly in a listening room for demo purposes. Dealers that "knew what they had" had L212 systems set up so they would knock your socks off and they sold them. Dealers who thought a loudspeaker sold itself and a room had no bearing usually had an L212 system stuffed in a corner and never moved a single one.

Basically one can place their system in their room either benefiting the decor of the room or benefiting the performance of the system. Most people naturally go for decor, whether that means "looking good" or "merely convenient". When someone mentions, for instance, that they owned 4343 (http://lansingheritage.org/html/jbl/specs/pro-speakers/1977-4343.htm)'s and didn't think the bass response was all that great, I surmise they probably suffered from poor placement. I've heard the 4343 sound terrible first hand and I've heard the 4343 sound fantastic first hand, and both instances were solely due to the environment.

"Are you able to simulate the effects of room gain with the un equalised sealed enclosure?"

Yes, BB6P can do that. It's easier with cars because one can pretty much go with "12 dB/octave rise below 50 Hz". If one is real serious they can measure their room gain and plug that information into BB6P.

Anyway, I guess this is getting a bit off-topic. Sorry! :D I've posted the paper on why to use a 2" compression driver instead of a 1" before. Search for Technical Notes Volume 1, Number 8. I believe it is in the "Ultimate Large Format JBL System" thread.

BTW, Nice 4345 Avatar Ian! :yes:

maxwedge
03-20-2004, 10:06 AM
Originally posted by Giskard
Just a reminder that any EQ added also affects group delay.
I was going to cut in the 50/80 range and bring it all up with amp volume. I think you said somthing like this dosn't effect group delay but you pay a price in efficency.

4313B
03-20-2004, 10:51 AM
Right