Speaker Experts... need your expertise (JBL 2123H)

[::::BASSIST::::]

I am building a small combo that will serve two purposes... 1. act as a powered vocal stage monitor. 2. act as a living room level bass combo.

I am using the gkmb200 built into a small-ish box that contains a 1-10. I did some experimenting and yanked a 110 driver from a junky bass combo that was given to me and put it into this unit I am building. The speaker sounds 'okay' for my purposes, but I found a decent deal on a JBL 2123H and was thinking of using that instead.

This combo will be mainly used as vocal stage monitor. However, from time to time I will want to use it to play bass with at very low volume. The other advantage is that the gkmb200 can be used as my backup bass amp at a gig or even poweramp for our small PA if need be.

My question is that the JBL 2123H seems to only go to 80hz according to the specs. Is that low enough to sound good for bass at living room volume levels? I dont expect it to sound 'awesome' but decent enough that it wont be a midrange bap bab bap kind of thing.

[will33]

80hz in what box? Any specs?

Anyway, if it can reach 80 it'll sound alright at home volumes. If you want it to be a decent vocal monitor, you have to give up some low response for higher response in the vocal range.

[::::BASSIST::::]

I should say I am FAR from a cab designer. I am mainly just doing this for fun. If it totally turns into a crap heap, I will just go buy a proper 110 monitor, but I am pretty limited in funds so I am trying to avoid that.

The box is about an 11" cube. It barely fits the 10 inch driver. Right now its sealed. I may add a port later. I am trying to keep it as small as possible so I can fit it into my car which also has to haul the PA, my bass gear and oftentimes the drummer's junk.

But yeah, vocal monitor will be its primary duty 80% of the time and as I said I dont expect the tone to be gorgeous... just useable.

[will33]

From what I could find, the 80hz on the low end and 6khz on the high are -10db. Would play pretty even, and incredibly loud from 200hz - 5khz. More of a purpose built mid that might a little bit of lows, like practicing bass at living room levels but probably not very deep. Haven't modeled it but I doubt your box is big enough to reach bass range. Looks like one helluva vocal monitor though, really impressive. Maybe someone else will see something I'm not here. What do they go for? Being JBL I would imagine quite a bit, but it look really good if your needs fall within it's strong range, like 110 vocal mons or 210+tweet mains.

[gigslut]

That speaker is the pro sound version of the E110, it has a little more excursion, but the xmax is not nearly enough for use as a bass guitar speaker. Off the top of my head, I wouldn't hit it with more than 40 watts with a bass in any enclosure. Run it through winisd and pay close attention to the excursion limits. You might get by in the living room, but it will be mostly midrange. A very nice speaker, but made for use in three way systems. Add a tweet and you will have a nice vocal monitor, but don't put drums or keys in the mix.

[will33]

Ya, some corrections. It is a big dedicated mid. The curve I was looking as was a ,25 cu.ft. sealed box, like a mid subchamber. Yours would allow it to reach a little lower but not really bass. It probably would sound like brap....brap to you on a bass although, xlim is way high, pretty hard to damage it. A damn loud vocal driver but should be crossed to a real woofer for bass use.

[gigslut]

http://www.jblpro.com/pub/obsolete/2123.pdf

Here's the specs. Xmax is listed at .1" and that is optimistic. The top plate is .28" and VC winding height is .42". Xlim won't be great with that short a coil. I built some boxes for these years ago for somebody. I used dual ports with a plug to block one port and drop the tuning for full range use. Tuned low the midbass is weak, but damage is averted at the lowest frequencies. I would still limit power in this application.

[will33]

Pdf lists xdamage at 19mm peak to peak although I see where you're coming from. I defer to hands on experience on this one.

[gigslut]

at 19 mm p-p the VC is exiting the gap on both ends. There would be gross distortion way before that and total loss of coupling when you get there. Speakers with thin top plates and short stacks can boast similar xmax to speakers with thicker plates and longer coils based on overhang (coil height - gap height), but beyond that point they distort quicker and are more prone to "jump out".

[::::BASSIST::::]

Well I asked for expertise... and you guys delivered!

So essentially as far as I understand what you are saying, it will be great as a vocal monitor driver, but not great as a driver for a very low volume level bass cab.

Correct?

[gigslut]

The overhang is similar to the E140, which was their bass guitar speaker, but I always thought that speaker lacked excursion and had way to much mid emphasis. Add to that a 10" cone instead of a 15" and you just aren't pushing enough air for bass.

[gigslut]

You could use it at home for practice, but will have to use a lot of EQ and watch your excursion. If it starts distorting back off! You don't have much headroom. Might not be worth risking such a nice speaker.

[::::BASSIST::::]

Alright duly noted. 80%+ of the time it will be for vocals only. And if I use it for living room jams as a bass combo I'll be careful. Sounds like I am getting a great price on it.

[ian_s]

Should be fine for the living room. If you want a box with a 10" that will give better response for both applications, look into a BFM Jack 10.

[billfitzmaurice]

Originally Posted by ian_s

If you want a box with a 10" that will give better response for both applications, look into a BFM Jack 10.

It's not even good in that. It's a dedicated midbass driver that should not be used on its own.