JBL 4425 Restoration

Zonker92

Zonker92

All shiny and chrome
[EDIT: This thread is a year old; I'm just trying to replace some of my pictures, missing after the migration.]

Thanks to awesome AK member mech986 (known to many as Bart) and a couple of weeks of very enjoyable tinkering, I now have some nifty 4425s for our master bedroom.

They started out as empty boxes; non-mirror imaged. I don't have a photo, but this is how they looked:

Bart hooked me up with two crossovers (with pots and L-pads), two horns, hardware, two 2416 drivers and two 2214H woofers. Bart drove the woofers down to have them refoamed at Orange County Speaker Repair. They came out like new.

I used this approach (thanks, Zilch!) to pop off one horn baffle and reverse it to make them mirror-imaged.

I steamed out some minor dents and lightly sanded the veneer, and used a hot iron to re-adhere some black vinyl trim that covers the edges of the baffle, and some of the grill cloth edges (reactivating the glue). I also cleaned the pots and L-pads.

Then I painted the horns and baffles with Duplicolor Bumper and Trim Paint (auto parts store). I made the stands out of some cut-down and repainted end tables.

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Wow Zonk, your the king of cheeks! :thmbsp:

I'll be picking up a pair of original owner piano black 250ti's very soon, Just need to do the three hour drive. Already paid for, so no surprises or disapointment. So I'll have quite a JBL line up here, there is a shootout in the works! :D
 
Sweet! I give you joy of those awesome Darth Vadars; I bet they sound amazing. :D

I am indeed feeling very cheeky today!
 
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Close cousins. I think the woofers might be different? Different cabinet sizes and crossovers, anyway.
 
RS Steve said:
Wow Zonk, your the king of cheeks! :thmbsp:

I'll be picking up a pair of original owner piano black 250ti's very soon, Just need to do the three hour drive. Already paid for, so no surprises or disapointment. So I'll have quite a JBL line up here, there is a shootout in the works! :D
Click to expand...

3 hours from Jupiter... sounds like my area. Did you score them on CL?
 
Bumping this olde thread for a few recovered photos; a lot of my links got lost in the forum migration. A year later, I can attest that these speakers sound terrific, clean and detailed, with a great soundstage and very impressive bass. We're using them in our master bedroom and they have sufficient bass for both music and movies.
 
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I remember those. You did an awesome job on them, great karma help, and nice to see the pics back!
Gives newer members the opportunity to see them too!
 
Read through it, thanks Zonker. I wish I had been a forum member when Zilch was still with us. Would have been great to have had some correspondences with him. What a talent!
 
Hi guys, I'm looking for some JBL 4425 advice. Any thoughts would be greatly appreciated. Here's the story. In the past I owned a pair of 4430's and absolutely loved them! However, I'm building a smaller recording studio now and thought the JBL 4425's would be a nice fit for a smaller studio to A & B audio with my Genelec's. So, I recently purchased a pair of JBL 4425's on Craigslist. The person I purchased them from said the woofers were refoamed. Not sure if they did a good job because on one of the speakers I can see the foam needs to be re-glued to the woofer, but the cabinets are over all in really nice shape.

The big issue here is when I plug them into my Crown Amp D60 Amp (56 watts per channel), without playing any audio through them, I hear this very quiet crackling noise?!?! It's a very annoying sound. Note: this is super old and beat up Crown D60 Amp. I'm aware the 4425's are 200 watt speakers, but I wouldn't think that a smaller amp would make them have a crackle sound without playing any audio through them? At the persons house that I purchased them from, I had him demo these speakers prior to paying, I def did "not" hear this cracking sound. The more I play them the louder it gets when the music if off. When music is on you really don't hear the crackle sounds so much, unless the song that's playing gets quiet. The crackle is more of a very big distraction and super counter productive for making making. So far I went out and purchased 12 gauge speaker wire and really nice banana plugs so I was certain the speaker wire connection was solid, which now it is. After doing that, no change, I still hear this crackle noise..... Next I'm going to try another amp, but I'm not sure if that's going to fix the issue here? Thoughts? If it is the amp, can you recommend an amp? I sure do love Crown Amps. Maybe I just need a bigger amp?

Also, there's one other thing I noticed. The high frequency and low frequency dials on the front of each of these speakers seem to be doing absolutely nothing.... With the 4430's back in the day I remembered that I could hear the change in high or low frequency when I turned the dial up or down, but on these 4430's I don't hear change when adjusting either high or low frequency dial, I mean nothing... Maybe there's just not as sensitive at the 4430's?

Thank you all in advance for your time, thoughts and any assistance - much appreciated.
 
Phil, with one exception, I've never seen passive speakers that were able to generate any spurious buzzing or humming sounds on their own. The exception were some B&W 802 Series 80s, and I'm pretty sure their 1,000 uF capacitors (acting as DC filters) had some stored energy. The 4425s don't have such large caps and my belief from here is that you're experiencing some noise from the amp, albeit enhanced by the relatively-high sensitivity of the 4425s. As you say, the obvious test is to switch amps, while making sure not to have any noisy source involved.

As for the L pads, IIRC the upper one just contours the upper HF a little bit. It's not dramatic but with some hiss playing its operation should be noticeable. The lower one basically adjusts the overall output of the horn driver, IIRC. A simple test would be to turn it all the way counterclockwise and see if the treble output vanishes entirely, as it should. It is, of course, possible that as prior owner bypassed those controls.

You should be able to re-glue that surround with Aleene's Tack Glue.

Good luck! None of those problems sounds insuperable.

I would also point you to the crossovers that my friend Matt is selling at Echo Mountain Audio. I was his test mule but have no financial stake in the enterprise. I have a pair and really like them, along with Radian horn diaphragms.

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Thank you for the reply! All the information you mentioned is very helpful!!

Amp: Purchased a Crown XLi1500 and that spurious buzzing or humming noise was 100% gone instantly. The old under powered amp was def the issue there.
Surrounds: I noticed both surrounds of both speakers were falling apart (yy finger went right through the surround when touching it). I purchased a replacement kit on https://www.simplyspeakers.com/jbl-speaker-foam-edge-repair-kit-fsk-jbl2214.html for my 2214H woofers. The replacement surrounds took about 1hr on each speaker and their video follow along was very helpful. They came out great and sound fantastic now!
L pads: I'll do the test you mentioned and report back.
Crossovers: Would the crossovers from your buddy Matt at Echo Mountain Audio that you mentioned replace the internal crossovers or is it an external rack mount crossover?
These speakers sound incredible, however I would love more bass out of them at normal listening volumes. If I crank them up really loud 80% to 100% volume, then I "get" the bass I want. However, when listening at 65% volume or lower they are def missing bass (which is kinda shocking for a 12 inch woofer). They sure do sound beautiful and they are a fantastic pair of studio monitors, but they're definitely not as bass heavy like the 4430's. I understand the 4430's have a larger woofer then 4425's 12 inch woofer, but my Genelec 8030C's have a 5inch woofer and at "lower volumes," the Genelec 8030's hold their own with these 4425's. At "higher volumes" the 4425's BLOW the 8030's to pieces over all, especially with bass. A little more bottom out the 4425's 12 inch woofers at "lower volumes" would go a long way, or maybe a nice bass bin, or maybe if they were soffit mounted?
 
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Delighted to hear of your progress! Matt’s boards won’t alter the bass response; electrically they result in output curves exactly matching the originals. The printed circuit boards install in place of the factory boards; they screw to the inside speaker terminal boards the same way, but are a bit larger.

Google the Fletcher-Munson curves if you aren’t already familiar with the idea: speakers definitely sound less bassy at lower volumes; I like loudness compensation for this reason. https://en.wikipedia.org/wiki/Equal-loudness_contour (I’m also a bass-head so now I’m using a B380 sub with my 4425s.)
 
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