Yet another 4425 project on the board

[bigyank]

Pics available soon. My question is I picked up a pair of used 2380A's for a song. Only issue is one is about a 1/16" of an inch larger (H-and-W).

Have a pair of newly foamed 2214H's from Gordon as well. :applaud:

My question is when did these horns sizing change and why? I have contacted my source to see if he has any of each size left so I can have an equal sized pair. :)

Yank

[bigyank]

So, I have decided to build my version of the 4425. The only thing the original and mine have in common is the fact that we both use the 2214H (which I got from GordonW:applaud:).

Here is the folder which will document the project:

http://s165.photobucket.com/albums/u60/bigyank_19320/JBL%20DIY%20Monitor%20Project/

The HF drivers and horns I got via that infamous auction site. They are the 2446H with 2380A horns. I did not realize when I decided to go this route for the HF how big these were actually going to be. I have to decide now whether or not to free stand the HF outside the box or not. I am leaning towards baltic birch for this project since my last speaker project (2007) used double refined 1" MDF and man that stuff was like working with concrete and just as heavy. I want to ultimately match the tuner case in my avatar which is black walnut veneer. Grill cloth will be from Zilch (I have ordered this cloth from him in the past and love the color).

Most likely will install 100 watt l-pads (any recommendations in this area are greatly appreciated).

I will be working on this with another member of this fine forum (Duaneage) who is not only a friend of mine but my mentor in these endeavours! :D

More pics soon as I have been busy with work which requires I travel during the week! :(

Any thoughts
Yank

[subwoof]

the 238X flat fronts have at least 3 generations:

The first ( 2380 ) was the resin foam casted thick walled shiny type. They had a habit of shattering on the road.

The second version has a very thin walled neck and was made out of the current type injection molded plastic resin?? Check the website for tech spec on the stuff ) BUT the neck was so thin, and the driver at the time 2445 ( 32lb of pure cantilevered weight ) snapped them off even with the ample bracing. Even in a friggin hanging CLUSTER.

The third version added ribs near the driver mounting flange that did help but 32lbs is 32lbs and drop drop means break break.

I think the most current version is a little modified but I ( and nobody I know ) uses 2" stuff anymore so it's conjecture.

The 2381 ( 1.5" as used in the 4726A and others ) are fiberglas as are the newer PT series. Nice weight and real strong.

Of course they have to be since the new drivers weigh a whopping 3lbs ( yep - THREE )....:)

And over the years I was building SR cabinets minor variations in hole locations and overall dimensions with these horns drove me nuts in the woodshop. I have one of every horn for template ( reglued road warriors ) and batch to batch ( or versions to version ) was not consistant.

sub

[bigyank]

And over the years I was building SR cabinets minor variations in hole locations and overall dimensions with these horns drove me nuts in the woodshop. I have one of every horn for template ( reglued road warriors ) and batch to batch ( or versions to version ) was not consistant.sub

I had to get 3 of these off the 'bay to get 2 the same diameters! :banghead:

Interestingly these 2 had almost sequential serial numbers (off by 6) and the 3rd one was way up there and is 1/16" larger HxW. :(

Was thinking that I might look for a pair of 2509 mounting brackets and mount these outside a cabinet, ala 4670D. :D

Yank

[duaneage]

The wood shop is going to be open for this and other projects this month. We will be doing two systems with 2214H woofers, I have plans to make a 3 way Studio Monitor version of the L100T in the form of the 4312 series.

[bigyank]

I think the most current version is a little modified but I ( and nobody I know ) uses 2" stuff anymore so it's conjecture.

:applaud:Hey, count me in! I am getting ready to use 2" drivers and have decided, once I (with Duaneage's help) swept the 2446's that some additional UHF help was going to be required:

I just purchased a pair of 2404H's off of the bay and once those get here, Duaneage and I are going to get working on a crossover design.

yank

[bigyank]

Virtual Crossover Box. Another neat trick Duaneage brings to the table. We used this for another DIY project we did last year (made the mistake of starting a project at the end of January during a cold spell :blink:).

Duaneage can elaborate more on the working of this box but being able to simulate values and actually listening to the driver is really nice!

Yank

[hjames]

Virtual Crossover Box. Another neat trick Duaneage brings to the table. We used this for another DIY project we did last year (made the mistake of starting a project at the end of January during a cold spell :blink:).

Duaneage can elaborate more on the working of this box but being able to simulate values and actually listening to the driver is really nice!

Yank
Whoa - looks like a very cool designing tool!

http://www.purebits.com/virtcross.html

[bigyank]

Heather you are correct................:D

It is the "right tool for the job", IMO.:)

Yank

[bigyank]

Okay so I am getting ready to rumble...................

I decided, while doing research here, to add some "sizzle" to the design and I am going to have to rename this project.

2404H

:D

They just arrived today from that infamous auction site safe and sound.

Yank

[bigyank]

http://i165.photobucket.com/albums/u60/bigyank_19320/JBL%20DIY%20Monitor%20Project/100_3103.jpg

So the first bass cabinet (on its side) being test driven last night. :applaud: 1" double refined MDF for the front baffle and 3/4" MDF for the remainder of the cabinets. I will eventually be posting "real" test results once I get them up and running.

Very preliminary testing but I like the results so far. :)Now I have to wait until I get off work so I can finish the other bass cabinet.

Yank

[duaneage]

We are going to finish the bottom ends today and determine the actual air volume inside the cabinets and adjust the final volume to 3 cu feet with a small amount of dampening on the cab walls. The side and back panels could stand some bracing and the box was oversized for this purpose.

The internal dimensions total 3.4 cu feet or about 11% oversize. with ports, woofers , coil resistance and bracing offset by fiberglass stuffing it should end up around 3 cu feet. The 2214 drivers are really well behaved in small enclosures, the 4425 being one example. The delay curves are excellent. Tuning will be around 38 hz and the dual drivers yield a normalized response of around 41 hz -3 db down. The power handling should exceed 400 watts in this cabinet versus a larger box (like the L100 T) where delay was sacrificed for bass extension.

The deep cones match well with the horn assembly, reducing the time delay effect. Crossover testing showed 2.0 mH to be a decent starting point with 33 uf across the drivers. THis should come in around 800 hz or so, matching the horn cutoff.

Hopefully we should be able to test with the horns in place on Saturday. I am anxious to run some test curves on the enclosures.

[bigyank]

http://i165.photobucket.com/albums/u60/bigyank_19320/JBL_Floor_Monitor.jpg

Here is the rough draft of my :)JBL Floor Monitors. I ran 110 watt/ch via a "vintage" Sansui receiver I had in the basement. Note the basement walls. My wife pulled rank and told me I had to build myself a man cave. No more audio stuff in the living room. They are approximately 47.5 inches tall.

Ran the first pass using Pink Floyd "Echoes" (always loved that song) with the L-Pads at "0". Holy s&it they are loud. Have to sound soak the back walls before I continue.

Yank:applaud:

[BMWCCA]

They look great. I'm surprised how small they actually are. They look absolutely huge in the pictures but according to your dimensions they're only about two-inches taller than an L7. Just curious; how do you suppose a DIY project similar to this using the LE120H-1 instead of the 2214H-1 would work? I may have some spares to play with.

[bigyank]

Used Woofer tester and WinISD pro with Duaneage's guidance (I am a TOTAL newbie but willing to learn) for the bass box design. if you have woofer tester you can get true thiele-smalle parameters and really design your boxes. Note: All 4 woofers have brand new surrounds (1 pair of these came from Gordon:D). One 2446H has a brand new diaphram and the 2404H's were swept and tested well within spec.

Even with only a rough draft crossover scheme the bass in these things rocks! :applaud:

We are going to have to pad down the midrange of these 2446H's. Holy crap are they loud. I listen to primarily hard rock (Led Zep, Pink Floyd, AC/DC, etc) so they fulfill that mission. I am surprised how clean the top end is with the 2404H's.

A lot of work still to go. Here is what we really leverage for crossover building a Virtual Crossover Box VCB-100

http://i165.photobucket.com/albums/u60/bigyank_19320/Frankenspeaker/100_2940.jpg

Like my pop always said when working on a job. Measure twice cut once. :applaud:

Yank

[bigyank]

They look great. I'm surprised how small they actually are. They look absolutely huge in the pictures but according to your dimensions they're only about two-inches taller than an L7. Just curious; how do you suppose a DIY project similar to this using the LE120H-1 instead of the 2214H-1 would work? I may have some spares to play with.

Thanks for the compliment. :D

http://i165.photobucket.com/albums/u60/bigyank_19320/100_3112.jpg

Just over 47" tall and around 100 lbs I think, I still have to weigh them.

Yank

[mech986]

http://i165.photobucket.com/albums/u60/bigyank_19320/JBL_Floor_Monitor.jpg

Here is the rough draft of my :)JBL Floor Monitors. I ran 110 watt/ch via a "vintage" Sansui receiver I had in the basement. Note the basement walls. My wife pulled rank and told me I had to build myself a man cave. No more audio stuff in the living room. They are approximately 47.5 inches tall.

Ran the first pass using Pink Floyd "Echoes" (always loved that song) with the L-Pads at "0". Holy s&it they are loud. Have to sound soak the back walls before I continue.

Yank:applaud:

SCHWEEEET!!! :applaud::applaud:

Looks like a modern update between the L150 and the L220 type concept. Probably ratchet up the bottom end if needed with a single 18 in a matching cabinet.

Love the ingenuity and concept.

Bart

[duaneage]

I decided to try a 3rd order network on the 2446H horns and a 1st order on the 2214H pair. Crossover is around 800 on the horn and 750 on the bass. The 2404 is using a 2nd order network and the 2446 has no top end crossover, we are using natural rolloff which appears to be 12db anyway. 2404 crosses at 10K

The initial testing with the 2446 showed they needed about 12 db of attenuation to match the dual 12's. This is one loud mid and properly attenuated it sounds wonderful. Power handling should be off the charts with that much attenuation.

The dual 2214H setup has a Zobel of 5.6ohms with 56 uf. I may replace that with 20 ohms of straight resistance, most JBL applications with these drivers used a shunt resistance, not sure why they went that way instead of a Zobel. Driver impedance runs around 3.2 - 3.9 from 250 Hz up to 10K with the Zobel. Lowest Z (Zmin) was 2.9 at Fbox of 39.4 Hz. I don't recall what the peaks were, when we are done testing I'll up the graphs. Either way, wimpy amps with undersized power supplies need not apply.

The third order HP on the horn is 17uf of polypropelyne caps with 1mh of shunt followed by a 47uf electrolytic cap. It's a Black Gate cap for those that care. The shunt inductor is aircore.

The lowpass uses a 1 mh iron core choke with low DCR of around .23 ohms. If BigYank decides to go with a hunky air core here we will need to retune the cabs as they are set for this DCR.

The cabs are 3.2cuft of working volume tuned to 39.4 Hz. Ducts are dual 4 inch tubes around 7 inches each, I think. Ql was not calculated yet because we need to seal the ducts and all that. Internal bracing is staggered mdf sections along each wall with a center brace front to back. The 50lbs of drivers on top of the bass cab helps dampen it a bit too. F3 with two drivers normalized to 0db is around 43 hz. Max SPL at 400 watts should be in the 123db range. WAF is pretty low at the moment but once they are finished in something other than MDF and wood putty we should get a better rating there.

I pleaded ignorance on the size and scope of this project to his wife. I don't think she believed me. These are bigger than the last monsters we built.

[duaneage]

They look great. I'm surprised how small they actually are. They look absolutely huge in the pictures but according to your dimensions they're only about two-inches taller than an L7. Just curious; how do you suppose a DIY project similar to this using the LE120H-1 instead of the 2214H-1 would work? I may have some spares to play with.

The 2214H is a rather interesting driver in that it does not go really deep in frequency but tolerates a wide range of box volumes while still managing to produce decent delay curves. It has excellent transient response no matter how you load it and works in small volumes too. It shares many traits with the 128H but the heavier and deeper cone increases the VAS significantly. The deep cone creates a further starting point for sound origination that improves time response with the horn.

I have never played with a LE120H-1 but I understand it is an excellent driver. I don't think it shares the same characteristics as the 2214H though. BigYank likes live concert music which tends to lack really deep bass while having untamed transients. The 2214H is a great choice for this style of music. While these drivers are not bass shy they don't have the low end of the 2235 or 2245, however they are also in 3.2 cu ft of cab not 6 or 8 feet. Such a system would be way too big for the application, the spousal unit dictated no more than 4 feet or else. We could have reined in another foot or two from the top box but having them separate enables a different low end to be built someday, like a single massive 18 or 15.

I had a pair of 2214H drivers in a Saturn 15 years ago. Knocked the rear view mirror down and made all the plastic in the car creaky. It was real hard to see the road when the volume was up.:bouncy: