E-120 Guitar Cabinet Suggestions

[Ed Zeppeli]

Hi,

I have a few JBL E-120 speakers that I'd like to make two 1 x 12 speaker cabinets for guitar.

I'm wondering if anyone has experience with these speakers in various configurations and if there are some good suggestions for dimensions. I understand they may do better in a 'closed back' cab which also doubles their capable power handling.

I've seen JBL's own enclosure guide which recommends a ported cab tuned to low E basically. Is this the optimum enclosure?

Thanks for reading,

Warren

[Aaron]

No matter what, the E120 will sound very lean and bright even if in a ported box.
That said, a ported box does sound like the way to go if you want to maximize low end output:

0.6cuft internal volume
3" ID port 4.25" long tuned to 70Hz

[Ed Zeppeli]

That's a puny box for a 12" speaker. It might barely be around 5" deep. Not really enough to accomodate a 4+ inch port let alone the depth of the speaker.

...or am I way off base here?

Thanks,

Warren

[Aaron]

I have to admit, I was only thinking of loading the rear wave to keep excursion under control and group delay response. I suppose a slot port with a 1"x8" cross section would at least fit on the front baffle...

Yeah, box size will be small for a driver with such a low Qts and Vas.
Also, you have to take into account the volume of air the magnet system displaces, the box will need to be a bit bigger than you think.

A compromise could be had with a 0.9cuft box, a slot port (10"x1") 3.5" long, still tuned to 70Hz. Internal dimensions could be: 13"W x 14"H x 9"D.

It won't have the smoothest low end ever, but then everything needs some EQ at these lower frequencies.

[Ed Zeppeli]

I have to admit, I was only thinking of loading the rear wave to keep excursion under control and group delay response. I suppose a slot port with a 1"x8" cross section would at least fit on the front baffle...

Yeah, box size will be small for a driver with such a low Qts and Vas.
Also, you have to take into account the volume of air the magnet system displaces, the box will need to be a bit bigger than you think.

A compromise could be had with a 0.9cuft box, a slot port (10"x1") 3.5" long, still tuned to 70Hz. Internal dimensions could be: 13"W x 14"H x 9"D.

It won't have the smoothest low end ever, but then everything needs some EQ at these lower frequencies.

The box will need to be bigger than I think?

I looked at JBL's reco of 1.5 cu. ft. tuned to 80 hz. I happen to have a Marshall 1912 cabinet that is virtually identical to the recommended JBL enclosure guide cab. One and a half cubic feet; two 2.1 inch untubed ports (holes) in the baffle. I swapped in one of the E120s and am pleased with the results but unfortunately these speakers had been reconed w/ aftermarket stuff and I've yet to do an OEM recone. So, I can't honestly say how these speakers as stock would sound in what is virtually a "recommended" enclosure.

As I understand it, TS parameters tend to be more redundant w/ MI speakers as flat response is not the objective.

Have you tried the speaker in such a configuration or is this just theoretical modelling?

Also, is it true that the aluminum cap makes it radically brighter?


Open to all input and thanks again,

Warren

[Hamilton]

I happen to have a Marshall 1912 cabinet that is virtually identical to the recommended JBL enclosure guide cab.

Those are great cabs, even for playing bass at low volume gigs.

[Ed Zeppeli]

Those are great cabs, even for playing bass at low volume gigs.

Oh ya? Did yours have a Celestion G12T-75 in it?

[Hamilton]

No, they have the 150 watt Celestion Powercell.

[Aaron]

The box will need to be bigger than I think?

What I meant was the magnet system, cabinet bracing, amplifier and port tube (if applicable) all take up some of the volume in the box, so the internal dimensions will have to be bigger than whatever internal volume you choose if you just punch in XXcuft x 1728 and divide that by H" x D" x W".


Have you tried the speaker in such a configuration or is this just theoretical modelling?

I have an E110 in an open back cab. It's VERY bright and miraculously has good low end.
I thought about putting it in ported box but decided I didn't need half the output I already had.

...To be more direct, I just modeled it. :o:



As I understand it, TS parameters tend to be more redundant w/ MI speakers as flat response is not the objective.

I keep forgetting the difference between sound production and RE-production...
you can probably tell, I work with home audio mostly.

As far as your boxes: use them. You might try some fiber fill in there if it sounds muddy.

[Ed Zeppeli]

Thanks Aaron for your reply.

Yes, it's the subjective nature of guitar speakers that confuses the issue for me as well.

I appreciate any and all opinions on what might make a good cab for this driver.

Cheers,

Warren

[jcrobso]

I have mine in an open back Line6 amp. Open back amps are good for guitar, the open back loads the speaker to about 80hz or so.
Are you only play guitar or maybe some bass as well?
Even though the E120 is guitar speaker it will work for bass in limited applications.
For bass a 2 cu-ft sealed box with fiber fill would work.

[Ed Zeppeli]

Well, i've been debating the idea of making two identical cabs for ease of portability.

I have this idea of approximating the JBL recommended 1.5 cu. ft. ported cabs but giving them a slight potbelly shape at the front. If I can get the right Tolex material one will be Marshall Blue and the other Wine Red; both w/ salt and pepper grill cloth. Then if I wanted to I could use them spread for stereo separation or stacked on their sides for mono and dual. I haven't seen anything like this for a guitar cab and am thinking it would look pretty good and sound even better.

On one of the cabs I'm thinking of a 1/2 back design for that openness/Fender twin thing you're describing.

The JBL cab guide says it's ported but if I understand the guide correctly, it's basically just a 4.2" hole cut into the 3/4" baffle.

I really like the idea of being able to use these for bass as well. You think a closed and larger cab would better suit dual purpose?

It's amazing how little info there is out there on the E120 in guitar cabs. All i've really found is the stock Fender info.

Thanks for the feedback, :)

Warren

[jcrobso]

http://www.audioheritage.org/vbulletin/showthread.php?23635-A-120-and-a-bullet-for-200.00&highlight=JBL+4602

I have this 4602 with a D120 and it works for bass in small places, I have thought about putting an E120 in and using it as a small bass speaker.
I did end up having a friend recone a E120 as a bass speaker we call it E120B.

[Ed Zeppeli]

http://www.audioheritage.org/vbulletin/showthread.php?23635-A-120-and-a-bullet-for-200.00&highlight=JBL+4602

I have this 4602 with a D120 and it works for bass in small places, I have thought about putting an E120 in and using it as a small bass speaker.
I did end up having a friend recone a E120 as a bass speaker we call it E120B.

Interesting. I checked out the specs on that Cabaret box and it's internal vol is 1.5 cubic feet. Same as what JBL recommends. Is that port hole in the box about 4.2" across?

Regards,

Warren

[jcrobso]

Interesting. I checked out the specs on that Cabaret box and it's internal vol is 1.5 cubic feet. Same as what JBL recommends. Is that port hole in the box about 4.2" across?

Regards,

Warren
I think it is 2.5" since it has D120, if I put a E120 in the box I would need to make the hole 4.2".

[Allanvh5150]

If you want the best of both worlds you could make a 1.5 cu ft cab with an open back and one with a closed back. Run them both together. As far as porting a guitar cab, not really much point.

Allan.