Yet another 4425 project on the board

[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.



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

Yank

[mech986]

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

SCHWEEEET!!!

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.