Jbl 10" vs le5 mid range

[ivica]

May also look into a 2155J. These are nice within their range, more efficient than an LE10, but not as much as a 2123.

I paid $125 for the pair plus shipping and except for some scratches on the front of the baskets from the prior mount, they are like new. These are 16 ohm and will require crossover mods. Also, these are just a bit smaller than the typical 10" requiring a smaller baffle cut-out.

Open back (35 mfd in series):


Closed back (~1/2 cu ft, 35 mfd in series):

Hi toddalin,

What is the scale factor applied to the amplitude axis ?
You have got very, very good price for a pair of 2251J drivers....

regards
ivica

[toddalin]

The scale is as you see it. Each horizontal line represents a span of 5 dB.

So what you see is the minimum of ~-75 dB @~420Hz to ~-61 @ ~3,800 Hz for a total span over the usable range of ~14 dB.

A 0.5 mH coil in series with the woofer reduces the 3,800 Hz peak/hump to a bit below that at ~600Hz also reducing this span. I've actually taken to winding my own coils for experimentation now that I have a meter that can read Henrys. When I do this, the crossover point works almost perfectly to the Heil on a 1st order 3.3 mfd cap with a bit of a dip between ~1 - 2.5 KHz.

It's amazing that with some of the chokes I have on hand, each wind of the coil will change the inductance by ~0.05 mH and I can wind/unwind the coil and see the results on the 61-band RTA in real time.

When I got my woofers, there was a vendor on the 'bay who had a bunch of these at this price. My pair have matching DCRs. I guess they're gone now.

[toddalin]

Hi toddalin,

You have got very, very good price for a pair of 2251J drivers....

regards
ivica

Actually, another vendor on the bay had a shiite load of 2123s that he was selling for $150/pr in excellent shape.

If anyone is looking for a nice pair of 2123s, there is a pair on C/L new in the boxes for $299/pr that have been listed off and on for a dog's age.

No affiliation.

https://losangeles.craigslist.org/ws...413973578.html

[toddalin]

Hi toddalin,

What is the scale factor applied to the amplitude axis ?
You have got very, very good price for a pair of 2251J drivers....

regards
ivica

I ported the cabinet and designed parallel passive bandpass filters and have the 2251J +- ~3 dB from <120Hz - >4,000Hz. Should do a beautiful rendition of vocals! I can't think of any JBL designs using a single driver that can achieve this.

Note the nice smooth "1st order" slope on top to the Heil, and smooth "quasi-2nd order" slope at the bottom to the 2241.