Cabinet for ME150H

[andy11]

I have a pair of brand new ME150H drivers that have been sitting in a closet for the past 2 years, which is a shame since these are such great speakers. I plan on building cabinets for them over the summer, but unfortunately I don't know much about box design. Anyone have any ideas? (I've attached an image of the Thiele-Small parameters below)

I plan on using them as home theater fronts, but will also be using them a lot for music playback. I have about 350 to spend on the HF drivers, crossovers and remaining materials.

I'm also trying to decide what to do for the high frequency drivers. I'm thinking maybe 1.5" or 2" compression drivers which should also cover the midrange pretty decently (but like I said I don't know much about design so this could be a BAD idea for all I know ).

Any ideas would be greatly appreciated!

Thanks,
Andrew

[Earl K]

Hi,

- Start with an enclosure that's 4.5 cu' ( net volume ) tuned to 30hz . ( Use 2 ducts of 4" inside diameter, that are approx. 12.5 to 13" deep to approximate this tuning ) .

- Discard from your memory those ts parameters that you displayed. Use the "ts" numbers from the 1500AL speaker if you want to play around with tunings and look at graphs .

Per your stated budget ( for the rest of the system ) :
- It's somewhat low , IME .
- Anyhow, buy some used 2426H ( not "J" ) 1" exit drivers ( maybe eBay ).
- You can buy new horns inexpensively from someone like PARTS EXPRESS (horns ) . They have ( for cheap money ) a Dayton horn that "looks" to be their standin for the JBL 2344. This horn appears to be limited to a crossover point of maybe 1000hz .

- The "Woofer to Horn" crossover point for your project will be a challenge . With you apparently having little to no test gear, you're limited to "guessing" at your net results and therefore living with the results . The ME150H has a significant response hole that occurs from 800 to 100 hz. That's why it's better to aim for a 750 to 800 hz crossover. To find a horn that effectively reproduces the lower driver frequencies means you're limited to buying used Altec 811s or 511s ( on eBay of course ) or something like them .

- Don't ask me what other small format ( no-name ) compression drivers may work at this low ( 800 hz ) a crossover point / I really don't know of any . - FWIW, I feel the JBL has more grunt than the comparable Altec at these lower frequencies .

- I recommend that you get a "paid-for", fully functioning version of TrueRTA ( along with a test mic like the Behringer 8000 model ) & assuming your using a PC not a Mac . A small investment ( such as this in testing software) , will immensely help any projects' final results .

[andy11]

Thanks for the great info!

I did a bit of hunting around since I posted my first message and I realize that my "budget" is a bit unreasonable. I do want these to sound as good as possible and I'd be willing to spend a bit more to do so.

As for the boxes, I've been taking a look at the design of the S3100 (thanks for all the pics Jan!), but building that horn seems to be a bit beyond my abilities. I looked at the horns from parts express and most of their better horns that have a minimum x-over point of around 500-800Hz are for 2" throat comression drivers only, except for one dayton which is a 100x60 dispersion elliptical horn w/ a min x-over point of 800Hz. Since there are many higher quality (Eminence, B&C, etc) 2" throat horns that are usable to 800Hz, would the 2446 work? I really like smooth highs and those drivers are supposed to be SMOOTH... or would I be losing too much top end?

Again, thanks for the help!

Andrew

[MatthiasA]

Hello i rebuild the S2600
(there is a DIY S2600 Thread in the Forum by me)
here you can see a few pictures of my Box
in the next time i will make a second one
if you need informations or cad drawings let me know!
please email me - (contact button - on my homepage)

greetings matthias

[andy11]

It's taken a while but things are finally starting to come together. I got my hands on two 1.5" throat B&C compression drivers (DE700) from a friend. (I know... not JBL ) Here's a link to the spec sheet http://www.bcspeakers.com/download/p...F/more/136.pdf. Please let me know if you guys think they will work, otherwise I guess I can ebay them and find something else. I also have 2 older QSC amps, one is 2x125W into 8 ohms and the other is 2x100W. They sound pretty decent and each has a really beefy power supply. I plan on biamping the speakers, which will also let me play around a bit with the crossover frequency.

I've been doing some reading up on horns and the P-audio PH-316 seems to be a pretty decent "cheap horn"... other than the drastic HF roll-off, off axis. I just might have to try a pair out.

The last problem I have is the box design. For anyone who owns a pair of S3100s, how is the low end? Is it pretty strong, or should I be looking to design my own enclosure?

Cheers!
Andrew

[johnaec]

I've been doing some reading up on horns and the P-audio PH-316 seems to be a pretty decent "cheap horn"... other than the drastic HF roll-off, off axis.

You ought to talk to Zilch about 1.5" horns - I think he's done tests on just about every 1.5" horn there is, including P-Audio.

John

[speakerdave]

. . . . The last problem I have is the box design. For anyone who owns a pair of S3100s, how is the low end? Is it pretty strong, or should I be looking to design my own enclosure? . . . .

I'm not getting why you don't think Earl's suggestions are useful.

David

[andy11]

I found Earl's post VERY helpful, but like I said earlier I have pretty much ZERO experience using box design software. I just thought that if if the S3100s sound really good, then why not use the same dimensions? For me this would be the much easier route as there would be much less guess work on my part.

One thing that I don't understand is the TS parameters. Why am I to use the TS parameters for the 1500AL? It looks to me like that driver is almost 99% different! Different cone, different motor structure, and different basket.... pretty much a completely different speaker. I'm just having a hard time understanding how the TS parameters of these two drivers would be exactly the same.

Anyway, It's not that I'm not greatful for the help... just thought using a proven enclosure would also be a good option.

[speakerdave]

One thing that I don't understand is the TS parameters. Why am I to use the TS parameters for the 1500AL? It looks to me like that driver is almost 99% different! Different cone, different motor structure, and different basket.... pretty much a completely different speaker. I'm just having a hard time understanding how the TS parameters of these two drivers would be exactly the same. . . .

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

David

[Jan Daugaard]

Hi Earl K,

in the section on transducers, the documentation for the ME150H is incomplete -- only 2 of the 5 pages are available.

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.

[Earl K]

Andy,

- I think copying an existing box size and tuning is a smart approach . That is essentially what my first post was all about .

- Do a search for Bernard ( in the "Search by User Name" box ) , coupled with S3100 entered into the "Search by Keyword" box . Select "display results" as posts if you want faster access to the search results ( bypassing the rest of the host thread ) . You'll find Bernard has a lot to say about the bass quality of his S3100(s) .


- I suggested ( start by building ) a 4.5 cu ft box ( tuned to into the very low 30s' ) for a bunch of reasons. One, this size is about the safest size box one can choose / for most JBL 15" woofers( that I can think of ) . Even 2225H and 2226H woofers ( pressed into HiFi duty ) will give decent performace in this size of box. Two, this volume appears to be the approx. enclosure size of the woofer chamber found in the S3100 . Maybe Bernard ( or Jan ) will remeasure a box for you so that you can arrive at your own conclusions . Another reason is , 4.5 cu ft does work quite well with a 2234/2235 woofer . ( ???, If you ultimately don't like the bass articulation from the ME150H, you may be forced to either build a bigger box ( and "slur" its' response some to achieve more bass ) or eBay these ME150H woofs and replace them with the venerable 2234/5 type / which come slightly "slurred" "comparitively speaking" right out of the shpping carton ). FWIW ; the 4344mkII ( which uses the ME150H ) would appear to have an approximate internal net volume of around 6 cu ft .

One thing that I don't understand is the TS parameters. Why am I to use the TS parameters for the 1500AL? It looks to me like that driver is almost 99% different! Different cone, different motor structure, and different basket.... pretty much a completely different speaker. I'm just having a hard time understanding how the TS parameters of these two drivers would be exactly the same.

- The "official" ts numbers you quoted within your first post are still pretty "questionable" IMO, and are most likely going to be more a hinderance rather than a help ( if you feel you must "tune by the numbers" to get to where you think you want to be ) . FWIW; A person who really cares about this stuff would measure the ts numbers on their own woofers ( and then use those to design by ) .

- I ( somewhat tongue in cheek ) suggested using the AL1500 ts numbers ( if you must play with graphics ) because those numbers happen to have a greater grounding in reality ( helped by Project Mays' studies and all the ts cross-checks run on that woofer ). FWIW; The "May" sims don't necessarily support the 4.5 cu ft as the "optimal" size ( for bass extension ) when tuning an AL1500 / but / ( and this is the big "but" ), Greg Timbers happens to like that size ( with a bit of VLF EQ to extend the bass ).

- I'm guessing you haven't actually run many SIMs for either of these woofers ( or else your questions should be more in the vein of WTF ??? )

[andy11]

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.

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.

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.

Cheers
Andrew

[Zilch]

The net internal volume of an S3100 cabinet with a different horn is not going to be the same unless that horn displaces the same volume as H3100 and its throat, or the dimensions are changed to compensate.

Fact is, enclosure volume +/- 10% doesn't matter much, as long as you have means to measure and vary the final tuning according to design or desire.

I like the angled back on S3100, actually. Most boxes are getting about 30° toe-in here of late, to widen the sweet spot. However, the S3100 baffle is overly wide for alternative horns.

[If I floated H3100 and driver I could get the volume.... ]

[andy11]

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.

[Zilch]

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.

You're not going to know until you measure the response of the driver and horn combined. That's a nasty breakup at 15 kHz; the utility of the HF extension depends somewhat on what the horn does with that. I've worked with worse....