These speakers had a good consistency to test with various situations. Special order items are NOT returnable. And the good thing about the LE5 drivers in general is that they are fast as lightning. We will cover the cost of return shipping if warranty claim is valid.
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From the beginning it was clear that this speaker might end up as a 3-way. As discussed before, restoring old speakers always leaves you with a lot of dilemmas. What should be left "as-is" and what should be modified to possibly enhance performance.
You easily get into modifying everything, leaving little of the original design and end up with a modern speaker made from highly tweaked old components with little resemblance of the real thing.
The L26 may not be one of the most precious gems from the JBL company and I have tried taking the middle road and added bracing to the cabinet, done only little to the drivers and most importantly, kept the LE25 for treble.
This is really not a bad tweeter, but it needs some equalisation to deliver the best. The one and only alnico LE to the left and the "modern" ceramic magnet version LE to the right.
Seen above left is the response of the LE blue and LE red on a 20 cm wide baffle. Overall sensitivity appear to be almost the same. The ceramic magnet on the LE is doing very well and from this presentation the LE seems like a much better driver compared to the LE, having a smooth response in the upper mid and lower treble.
The frequency response turned out just as bad as the LE I really thought this alu dust cap was crap and then it turns out to be much better than the paper "bowl" of the LE So what to do? A rubber dome on a JBL driver?? Right: The response of the LE with alu dome red and with rubber dome blue. So in went the rubber dome as seen on the photos below. LE with alu dome removed to the left felt material added the polepiece for damping - and LE with rubber dome to the right.
Even if they have minor bumps I recommend leaving them in place. Not bad at all. As soon as the LE5 mids sees a wide baffle, the response below Hz rises some 4 dB, the LE even worse than seen here. One of the reasons for this is the very high Fs of the drivers as seen below. These LE5 mids really behave more like giant tweeters than middrivers.
They would fit in well with the old Wharfedale open baffle speaker with its up-firing 3" "tweeter". Working on 1st order filters often takes a notch filter to flatten the impedance and a LCR circuit is actually used to create the acoustic roll-off needed for the LE Another thing about the LE5 mids - and this is the last one - is consistency. As can be seen on the graph above, the impedance of these two drivers are not exactly the same.
I mean, you wind so and so many turns one way and so and so many turns back again to make a two layer voice coil. How tough can this be? A fabric spider and a rubber or foam outer suspension is likely to produce the same compliance all the time. Seen above is the very simple 2nd order crossover for the LERD middriver. Whether the points of crossovers are going to be Hz and 3. And the good thing about the LE5 drivers in general is that they are fast as lightning.
Very lightweight paper cones and very strong motor systems. Quite some work! The old front panel was cut off by a jigsaw and the remains removed with the router router bit with a wheel. The middriver takes a cabinet and this one is x x 96 mm made from 12 mm side panels and 16 mm bottom panel producing 1.
Bracing made from 12 mm MDF was added to the cabinet as seen on the photos. And I had to cut out for the mid enclosure. Fillets were added to support the front panel. The LE25 cut-out needs "ears" for the terminals and these are not 45 deg to the horizontal alignment. Put the tweeter into the hole and mark the placement of the terminals to route for the "ears". The middriver really needs serious chamfering to allow free air ventilation.
The LE5 mids have almost all the ventilation to the sides and need a lot of chamfering to breathe and not sound congested. The rear panel is attached to the side panels by a notch in a groove and can actually vibrate a lot. Loads of PVA glue was added and I left it overnight to dry. The hole for the terminals were chamfered as seen on the photo to the right and a 19 mm MDF block was glued to the inside for the new terminals. I like the original oak veneer and this was one reason for keeping the olds cabs.
Adding bracing and make the best of it. The cabinet panels are made from chipboard and I see chipboard coming back in a few constructions Living Voice. The veneer was sanded gently and is ready for a new oil rub. The vent? You may already have wondered where the vent has gone. Well, the A bass driver has a high Qt and is really not suited for bass reflex designs.
If you want to know more about an acoustic vent, I suggest you read the isssues of HiFiWorld where the Dynaco A25 has been revived with the use of an acoustic vent. Usually an acoustic vent provides a more amplifier friendly impedance profile. Should you decide to stay with the vent, here are the dimensions of the original: Front panel driver layout and port Left: As always: The placement of the drivers have a major influence on the response of the drivers and I suggest you follow this layout to make the crossover work properly.
In particular this is important for the middriver as seen above. The front panel was made from 22 mm MDF. The bent tube is very suitable for long vents.
All internal panels except rear panel were added 10 mm polyester foam. Rear panel had 30 mm "wave" polyester. The crossover will be on small MDF blocks over the terminals in the middle of the cabinet. Rear routing for the acoustic vent. Right behind bass driver.
Centre mm from bottom. To the right: Front panels after adding laquer for saturating the MDF to allow the use of water based paint. The cabs were finished during the summer holidays and the sanded veneer was given a fresh oil rub. Gut feeling tells me the crossover option is the most likely to succeed. Gut and gut This will be reported later, but what was apparent was the point of crossover between bass and mid. The LE5s are more like mid-treble hybrids and should be treated accordingly.
JBL LE5-2, LE5-8, LE5-9, LE5-10, LE5-12 Aftermarket Recone Kit LE52
This is a learning curve for me. I also do not have the product break down on every fricken 4" mid JBL ever made. They all look the same. That is what the forum is all about talking, teaching and learning!!!!!!!!!!!!!!!!!!!!!!!
5" JBL Style LE5 Midrange, L36, L100, 4311, Others, M-LE5
The 12" woofer JBL A in particular is a gem. Black crackle finish covers a cast aluminum alloy frame. The motor contains a 6 lb. Alnico magnet of 10, gauss with a 3" edge-wound copper ribbon voice coil.
JBL C8RLE52 L100 LE5-2 Midrange Recone Kit
Ditaur All kit and component prices may be subject to change and are always to be confirmed by Jantzen Audio Denmark. Mid, tweeter and summed response. The video instructions have been unusually helpful, especially the hints to apply adhesive to the back side of the foam before turning it over and attaching it to the cone. For additional information, see the Global Shipping Program terms and conditions — opens in a new window or tab. Mouse over to Zoom — Click to enlarge.
SS Audio Recone Kit for 5" JBL LE5 Series Midrange, 8 Ohms, RK-JBLLE5