Extended Range LE5

[Joe Alesi]

Hello All,

It is not uncommon for some vintage and/or fullrange drivers to operate without a dustcap, or with a veil like, but acoustically transmissive dust cap or to even use a phase plug to help generate some extended response.

Has anyone tried modifying the LE5 by removing the dustcap and or adding a phase plug to the LE5 (preferably LE5-2)?

I have seen some published data from JBL for some LE5 models, but never for the actual LE5-2. Could anyone please provide (or point me in the direction of) any genuine JBL or measured frequency response data for the actual LE5-2?

Also while I have your attention- what is the lowest frequency people have used with the LE5 (300 Hz probably??) I was thinking of running these as low as possible into a 2226 per channel. I know I should probably keep away from 300Hz and run the 2226 higher, but I am curious about your experiences.

Thanks in advance for any info.

[Robh3606]

Hello Joe

Welcome to the forum! Take a look here, this is as close to what you are asking for that I know of off the top of my head. You could try searching, you may turn up a bit more. Have fun!! Let us know how it worked out if you decide to try adding the phase plug. Running them to 300Hz?? Why not let the 2226 come up to 800Hz or so. It can do that quite well with no issues. You can always try it but I think you would really be pushing the Le-5 hard at any elevated listening levels. That's a small cone area wise. Is the Le5-2 sensitivity high enough to match up with the 2226???

http://audioheritage.csdco.com/vbulletin/showthread.php?t=5706

Rob:)

[speakerdave]

There's a frequency response curve in the date sheet on the 2105 in the library here:
http://www.lansingheritage.org/html/jbl/specs/pro-comp/2105.htm
Not exactly the same driver, either, though. This driver is suggested as a full range for SPOKEN VOICE. The curve falls off below 200 and is not charted below 100 Hz.
For music at power the recommended crossover frequency for the LE5-2 is 800 Hz.

David

[Joe Alesi]

Hello Rob and David,

Firstlly thanks for the welcome. Thanks for your responses- just what I needed. Unfortunately my previous searches searching didn't find those hand drawn curves or alnico version data sheet for the 2105.

Out of curiousity only, I want to try the LE5-2 with as low a crossover as possible, just to get it as far away from 1000Hz as possible, where crossover is often more obvious and radiation patterns differ significantly in other speakers I have used/made. My ideal would be to make a minature "fullish" range driver by modifying the LE5. 200Hz to 15kHz ±3dB (dreaming.....) would be great. I would mount them in minature enclosures for and unobtrusive look and use electronic crossovers so that I can easily set the levels/crossover frequency to my hidden 2226 (sub?)woofers.

You are probably right that running the LE5 close to 300 Hz is questionable. It may be risky at higher levels or sound rough near its resonance (which interestingly from your data varies quite a bit: from 130Hz to 300hz). Anyway, I am willing to risk one driver for testing/modification. I suppose I can always re-glue the dustcap if my trial doesn't work. If I go ahead with my mods I will try to get some before and after data and post this.

Thankyou both again for your input. Also thanks in advance to anyone else who chimes in.

[soundboy]

Just FYI, I found that back in the day, the ceramic magnet LE5 was MUCH smoother and more transparent sounding over the LE5 2. It is also verified somewhere on here that when they switched to ceramic, the distortion products were a fraction of the alnico in this particular unit. It sounded like that to me, as well....made my old 4315's sound a bunch more listenable....My question is...why are you doing this? Why are you second guessing the origonal engineers, and running a pro 600 watt, 97 db driver with a colored, peaky, 5 inch that is at least 4 db less efficient, and designed to cross over at least 2 octaves higher for high power? What is your goal? Musical accuracy, or ??:blink: I spent many an hour playing with a lot of these wonderful drivers over the years, as well...I would suggest a 104H as a smoother alternative, and perhaps use a 2118H or 108H (hard to find) between the 2226 and 5"....for that matter, the 2226 only goes to barely 40HZ, as they are designed as a high power/efficiency PA driver...I have used them too for live sound...you won't be happy for low bass in a home system IMHO. You will need a subwoofer below that.....for movies, etc...all I am saying is, perhaps re think your driver/crossover point choices and goals....what you are doing will only bottom out your LE5's the first time a snare drums hits them.....just tring to help save some time....I have done worse things when I was starting out....how about a 8" JBL 2110 with a piezo tweeter??? It sounded ok (compared to??)with the vinyl of the day, until the bass bottomed out the voicecoils regularly!!...Above all, have fun...Pete

[speakerdave]

. . . . My ideal would be to make a minature "fullish" range driver by modifying the LE5. 200Hz to 15kHz ±3dB (dreaming.....) would be great. . . . .


You might--
1--settle for 8-10k and add a supertweeter
2--in an MTM arrangement, which has some of the advantages of the fullrange
The spacing between the LE5's would give you boost in the lower frequencies via acoustic coupling.
Put a zoebel on the LE5's to tame the rise.

I agree with soundboy on the sound of the later, ceramic LE5's being smoother sounding than the earlier Alnico ones. It's not the magnet that makes the difference in this case.

I think you should listen to the LSR32 and/or its successor the 6332 and see what you think. That 5" midrange (neodymium) is run from 250-2.2K; (it's available from JBL Pro). That gives you a lot of what you're after. Those speakers are very good. By the way, the woofer from that speaker is much more suitable for what you seem to be trying to do than the 2226. It is also available from JBL Pro.

David

(Edit: Actually even 8k (4315) is too high for the LE5. But now this is becoming an interesting problem. Exactly how can the LE5-2 be used?)

[Joe Alesi]

Hi David and Pete,

The 2226/LE5 thing is just a bit of a experiment to see how good a sound iI can get from miniboxes which are as full-range as possible. Thanks for the suggestion about the ceramic mids I will try to check this out.

When I finally get around to it: I will use the 2226 (As I already have a pair of these in good quality 110 litre ported boxes that I got for a song) with some 2440 and 2401/5 I have. Unfortunately I sold my 2235 (mistake many years ago), but I still have the custom eq (active filter similar to BX63) that I built for it. I was going to try to retune it for my 2226 drivers, although not sure how much success I will have as I will be trying to eq below the 40Hz free air resonance of the driver and as a result distortion or excursion limitations may be a problem at higher levels. Whilst this remains to be seen I am encouraged by the Erik Tongen (I think) 2226 (sub)woofer. (notice the brackets on "sub" for any perfectionists out there)

Great Forum Guys,

[Joe Alesi]

Hello Rob and David,

Anyway, I am willing to risk one driver for testing/modification. I suppose I can always re-glue the dustcap if my trial doesn't work. If I go ahead with my mods I will try to get some before and after data and post this.

.

Hello All,

OK so I measured an UNBAFFLED LE5-2
1. In standard form RED
2. with dustcap removed BLUE
3. with dustcap removed and a small 1 inch long 1/2 diameter pointed "phase plug" fitted (with blu tak) GREEN

I will post the response graphs later, but it is enough to say that there is no further HF extension using the phase plug, but there is some extra (1dB) which helps fill a hole at 3 and 5kHz.MY CONCLUSION- guess what- for all the effort possibly leave it the way it is or go for the extra dB if you must.

EDIT: added graphs:


Best
JA

[duaneage]

The 5-2 and most other LE mids were designed for use in the 800hz to 4.5Khx range. The natural rolloff was used in the slope and once in an enclosure a rise occurred on the lower end.

The later midranges had batter responses, the 5-2 was an early model, by the time they made the 104H series the line had improved. Although for some reason the 5-2 sells for big bux on ebay.