Cabinet for ME150H

[Zilch]

Isn't there a board that separates the bottom portion of the box form the top, making it into 2 separate encolsures? I think Mathias called it a "plate" when he was making his S2600 copy. Even if that's not how the S3100 is made I think I will use that design. That way I don't have to worry about taking the volume of the horn into account when building the box.

I believe you'll find that S2600 is two chambers, but S3100 is not. Matthias discovered that early on, as I recall. It's a "plate" in S2600, but an open brace in S3100. See here:

http://manuals.harman.com/JBL/HOM/Te...S2600%20ts.pdf

http://manuals.harman.com/JBL/HOM/Te...S3100%20ts.pdf

[andy11]

Ah yes... I see. Crap!

And hopefully that nasty breakup of the CD is from the horn it was on.

[Zilch]

4430's 21-7/8" wide, and shallow (14-13/16").

I'd be looking to build John W's uber-cool trapezoid design:

http://audioheritage.org/vbulletin/s...ead.php?t=9695

Just fatten the base a bit to accommodate the 15" driver and get the volume you need, tapering the sides to the same size as John's at the top.

[Zilch]

And hopefully that nasty breakup of the CD is from the horn it was on.

If it doesn't work, as you say, you can always fall back on the proven 2344(A) and 2426H plus NL200t3 crossover in the same cabinet.

Guido likes the PH-316. I have a spare pair. PM me if you'd like to acquire them....

[Earl K]

Yeah, it is a little puzzling, isn't it.

- To plum these depths of puzzlement and paradox, one needs to own a pair of these woofers. I think you'd like and appreciate them ( that based upon your comments about the 2235H not being a direct "voicing" replacement for the 2231a(H) in a 4333(a) system ). That does set you apart, since most people never seem to get past the consensual LHF "hype", awarded to the 2234/5H .

Do you have the missing pages? And, if so, would you make them available? You state that the ME150H has a response drop between 800 and 1000 Hz, so you must have seen the documentation, including the frequency response.

- No, I've never seen the missing pages of the official JBL documentation . I was as surprised as anyone when Giskard posted that ME150H info. He had previously stated that it, and the ME120H info were both lost to antiquity ( if my memory of events is accurate ) .
- The response drop between 800 and 1000 hz is based on my own RTA measurements of the 2 ME150Hs that I listen to . ( I didn't measure the other 2 that I own and presently sit in storage ) .

Since I posted my last reply I plugged the numbers for both the ME150H and the 1500AL into bassbox and did some playing around. Not as hard as I was expecting! A volume of around 4 - 4.5 cu ft tuned to around 32Hz produces some nice results for both drivers. Things start getting nasty if tuned below 30 Hz and doesn't seem like it will play deep enough if tuned above 35 Hz, so I'm thinking 32 is just about right.

Good, now run some SIMs for both the 2234H and 2235H in similar sized boxes ( 4 and 4.5 cu ft ) keeping the same tunings. Also run some SIMs for 5 and 5.5 cu ft enclosures with tunings in the low 30s' . You should find that the 2234/5 "tune-up" quite a bit nicer . Too bad we don't really listen to SIMs .

Now I'm wondering why you suggested using two long ports instead of one shorter one? Only reason I can come up with is air velocity which would in turn create port noise... but maybe I'm way off here.

I'm not really sure why I recommended 2 smaller ports versus 1 larger one. It might have been based on having more length to work with, when trimming the tubes to achieve a desired Fb .

Anyone take a look at those specs from the compression drivers? If so, do they look ok (other than the fact that they're not JBL )? To me it looks like they might sound good. Bit of a dip around 2k which should make them sound less harsh/nasal, and extended top end which might work well with 4344/PH-316 horns.

- I haven't heard that particular model though I own a pair of their neodymium magnet, 3" titanium diaphragmed, DE900 model . I also own some DE45s ( 1" exit ) small format titanium diaphragmed drivers. Neither of these models are listenable ( IMO ) within the home environment / though their Mylar diaphragmed drivers are very listenable ( I also own some DE25s & DE16s ).
- Hold out and buy a pair of those surplus ( JBL ) 2435HPL that keep appearing on eBay. They'll be a much better investment in the short and long run . 2426H drivers are still a good mainstay driver and right now a good bargain when purchased directly from Harman .

[andy11]

I'm gonna keep my eye out for 2 used 2426Hs that I can afford... I'm a student and have a VERY limited budget so new ones, and 2435s, are pretty much out of the question at the moment. But in the meantime I'm going to try the CDs I've got. Like I said, I can always ebay them if they sound bad.

Once I graduate and get a real job I'll start on a proper, no holds barred project , but until then my "limited budget project" will have to do.

Thanks again for all the help!!

Andrew

[Bernard Wolf]

I'm gonna keep my eye out for 2 used 2426Hs that I can afford... I'm a student and have a VERY limited budget so new ones, and 2435s, are pretty much out of the question at the moment.

Andrew

While you are on the lookout keep an eye peeled for a single 275nd... I will be very happy to trade you 2 2426H for a single 275nd ... I want to turn my 3100's into MK II's.

Thanks - Bernard

[andy11]

will do!

[andy11]

After some more reading I'm thinking a high-pass filter will be needed for these boxes. The low-end roll-off looks a bit steep and I'm starting to worry about overexcursion. Just wondering if I should build a passive high-pass into the boxes, or use an active design. I also have an eq, but I'm thinking an extreme curve may cause some phasing issues. What's my best option?

[andy11]

Another question... How far from the center of the me150 should the horn be mounted? Am I safe to assume that closer is better?

[Earl K]

After some more reading I'm thinking a high-pass filter will be needed for these boxes. The low-end roll-off looks a bit steep and I'm starting to worry about overexcursion. Just wondering if I should build a passive high-pass into the boxes, or use an active design. I also have an eq, but I'm thinking an extreme curve may cause some phasing issues. What's my best option?

- You may want to build ( or buy ) an 18 db/octave highpass filter, set to around 20hz.
- You'll only need this hipass circuit if you decide to electronically "boost" the VLF bass frequencies because you find a ME150H in a 4.5 cu' box, "VLF-shy".
- Like the 1500AL, the ME150H responds nicely to VLF EQ ( highish "Q" )
- Urei used to make a mono unit like this ( with a bit of EQ I believe ) / back in the 1980s' .
- FWW, , most modern ( stereo ) electronic crossovers come equiped with a builtin 12 to 18 db hipass filter .

- Since you've stated you're a student ( & I assume relatively young ) your appetite for VLF is quite likely a lot more voracious than those of us in the 50 plus age range. As a consequence, you may find the extra articulation built into all of JBLs' newer SOTA drivers, not to your liking . You really may need to use EQ to get these woofers to give you the"sound" that you are after. I earlier mentioned that a 2234/5 type woofer might suit you more / since they require little EQ to please most people.
- I previously mentioned the 4.5 cu' enclosure size because it's a nice compromise that works well enough with both JBLs' newer & older woofers .
- Also, since you're a student, moving your belongings many times is in the stars / so ultimately, size matters .

Another question... How far from the center of the me150 should the horn be mounted? Am I safe to assume that closer is better?

Yes, closer is better. I'd make it so that the horn-edge is almost touching the rim of the woofer .



ps ; I wouldn't overthink all this too much / remember / your "first build" is unlikely going to be your "last build" .

[andy11]

My Rane crossover has an 18db/octave high pass at 20Hz built in! How perfect is that? Guess that's one less thing to worry about.

As for your comment about bass response... I may be young, but I definitely appreciate accurate/articulate response. I grew up listening to a fairly high-end system, (Luxman amp, Mission speakers, NAD CD player, Dual turntable) so I'm pretty sure I know what I'm getting myself into. Am I right to guess that these will have a very damped sound? Seems to have a pretty heavy cone (Aquaplas) so I'm thinking this will be the case. If so, I think I'm really going to like them. This is not what I was originally expecting as I always associated jbl with kind of the opposite... but this is definitely not a bad thing!

Since I was originally hoping that these could double as HT fronts, it looks like a sub may also be needed in the future. Any more more sub1500s kicking around? While I'm still on the subject of subs, has anyone tried the EAW or QSC theater subs?

[Earl K]

As for your comment about bass response... I may be young, but I definitely appreciate accurate/articulate response. I grew up listening to a fairly high-end system, (Luxman amp, Mission speakers, NAD CD player, Dual turntable) so I'm pretty sure I know what I'm getting myself into. Am I right to guess that these will have a very damped sound? Seems to have a pretty heavy cone (Aquaplas) so I'm thinking this will be the case. If so, I think I'm really going to like them. This is not what I was originally expecting as I always associated jbl with kind of the opposite... but this is definitely not a bad thing!

- I'm glad you have a growing awareness of what this model is all about .
- The cones are mechanically/sonically well damped. Electro-mechanically the motor-drive system is very damped. So overall this is a very "tight" sounding woofer.
- I have two in 2.8 cu' enclosures ( tuned to @ 40 hz ) / arranged in an MTM setup / and I constantly catch myself thinking ;
" Why do these sound like twin 8" woofers ? "
- BTW ; I consider that a compliment to the woofers' designer.