Replacement for a JBL E145

[davidlovellbass]

I bought a cabinet with a JBL E145 after reading how good they are as a bass speaker, sadly great tone comes in at about 50 Kgs for a 1x15 cabinet. The other problem is the cabinet design isn't standard either as it's a Karlson design so working out the internal area is a bit harder.

Anyone have any ideas for a replacement speaker that isn't so heavy?

[Bill Fitzmaurice]

[quote name='davidlovellbass' timestamp='1402165233' post='2470694']
Anyone have any ideas for a replacement speaker that isn't so heavy?
[/quote]There are many, the problem is matching anything to a Karlson box. It's a seat of the pants design that can't really be software modeled to get a good driver match.

[davidlovellbass]

I was hoping to swap the JBL out for an Emience basslite C2515 but spending out for a speaker that could sound bad isn't very appealing

[Bill Fitzmaurice]

[quote name='davidlovellbass' timestamp='1402226374' post='2471094']
I was hoping to swap the JBL out for an Emience basslite C2515 but spending out for a speaker that could sound bad isn't very appealing
[/quote]You need to go to the JBL Professional site and download their T/S spec sheet, then find a driver with similar specs to the E145. However, that only shows the low frequency compatibility, up to about 200Hz, not the midrange. You'd need to compare that on individual driver data sheets. The kicker though is that doing this only gets you something that's similar to the E145, it doesn't mean it's a perfect match to the Karlson, which the JBL may or may not be. Kep in mind that the Karlson dates to circa 1950, the E145 to circa 1970, so the Karlson was not designed using the E145 as a test driver.

[Dad3353]

Good afternoon, David...

Are you sure you're looking at this from the right perspective..? (Disclaimer: I'm far from expert in these matters, but know a little...). The Karlson box was a hifi/pa experiment which had a modest fashionable spate in the '60s or so, but was never really considered for mainstream instrument use, afaik. The JBL, on the other hand, has had a solid reputation for decades, and remains, for many, the 'king' of that generation of speakers. There have been evolutions in both cabs and speakers; the Karlson has been left behind, but the K145 still has its place in the 'usable to extremely good' spectrum, despite its age. In your position, I would be looking to find a suitable cab for the JBL, and ditch the Karlson, rather than the opposite, as it is at best a compromise, optimised for nothing and inherently difficult. It's also heavy, by its construction. What are the qualities of the cab that you're looking to keep..?
I'm not sure that this help much; sorry, but I'd like to hear your reasoning.

Edited June 8, 2014 by Dad3353

[davidlovellbass]

Thanks for the help guys. I'll have to start A/Bing spec sheets and see what'll work. It's an odd cabinet and one with quite a bit of history of pro player use so it seems a shame to ditch the cabinet. The other question would be finding a cabinet that'd work with the JBL and not cost a fortune

[JTUK]

Yes... I'd go with utiising the chassis and binning the cab as that is where all the weight is.
I think it would be far easier to find/buld a cab around a decent unit.. than find a speaker to fit the cab.

[Balcro]

Hi daidlovebass,

The E145 is definitely the thing to keep. It seems to be under-rated. so much so that it will probably last for many more decades.

I've run it's specs through winISD, the first JBL I've checked, and it's the first unit I've come across that handles more than it's rated capacity and laughs at the amp power! It handles the full 150 watts all the way down to it's fundamental resonance @ 35Hz. I think that's it's thermal limit, but at the same time it never exceeds the mechanical "xmax" until the same low point.

Where most (not all) reflex-port loaded drive units show a sharp dip in mechanical capacity between 55 - 70Hz, this thing just keeps on going. Mechanically you can simulate a 600W Rms input and that 55-70Hz band is still below xMax! That's rugged.

Enjoy,

Balcro

[Bill Fitzmaurice]

[quote name='Balcro' timestamp='1402308063' post='2471833']
I've run it's specs through winISD, the first JBL I've checked, and it's the first unit I've come across that handles more than it's rated capacity and laughs at the amp power! It handles the full 150 watts all the way down to it's fundamental resonance @ 35Hz. I think that's it's thermal limit, but at the same time it never exceeds the mechanical "xmax" until the same low point.
[/quote]It's certainly better than most vintage drivers, but today the 7mm xmax is about average. The main issue with it is the low (0.25) Qts, which chokes off low frequency response. In that respect JBL made it 'too good', as were most of the D, K and E series drivers, which were designed before T/S. Only after T/S came along was it understood that, while high sensitivity was in general a good thing, it could be overdone.

[davidlovellbass]

Thank you all for the responses, I never gave the speaker specs much thought as the cabinet never sounded like it was being taxed at any volumes.
Where could i find a cabinet design that'd use the speaker to it's full potential? I don't have a cabinet design program but making one isn't beyond impossible or would an existing brands cabinet work just as well?

[Balcro]

[quote name='davidlovellbass' timestamp='1402762606' post='2476644']
Thank you all for the responses, I never gave the speaker specs much thought as the cabinet never sounded like it was being taxed at any volumes.
Where could i find a cabinet design that'd use the speaker to it's full potential? I don't have a cabinet design program but making one isn't beyond impossible or would an existing brands cabinet work just as well?
[/quote]

From doing another run-through using the winISD modelling program, you realise that the E145 is very versatile, in that you can tune it to a variety of sounds. You can extend the low frequency response, you can tune it for a "flattish" frequency response with a slight low boost in volume, or raise the tuning to give a warm low-mids. It doesn't care.

It also seems to be quite capable of working in a wide range of cabinet sizes; perhaps in the range 65 - 150 litres. Of course, the smaller the box the lighter it will be. My impression is that maximising it's true potential is for a nearly flat response with some low bass extension.

For an example of what might be suitable as a cabinet design, take a look at the "pinned" DIY cabs section of Amps & Cabs. On page 1 post #8, dated 25/5/07. richardH shows a nice 1x15 fitted with an EV speaker. Something along those lines would be good.

There are two things to consider if you want to buy a 1x15 second-hand cab of similar size:-
The diameter of the existing screw/mounting holes in the cab and whether they match the E145. Probably not; so they may need to be re-drilled. Secondly, the baffle hole may need to be re-routed to match the speaker frame.

Balcro.