2123H vs 2122H in a 4343 monitor

[boputnam]

... no doubt incomprehensible for others.

That's the best part about this forum - contributions range from from reveling in joy of finding an old pair of JBL's to incredibly insightful engineering pursuits.

I was rivited by the thread you refer to - I found myself reading and re-reading it. While exhibiting a high level of understanding, all the posts in that thread were incredibly legible and supported by graphics. While not contributing to the thread pesonally, I found much that matched observations of my own, which I didn't understand the reason(s) for. That said, the discussion of the change in the voltage drive of the 2122 when going from passive to biamp has caused me to go take additional measurements out of curiosity.

You can't match the depth of this place.

[Ian Mackenzie]

We must remember most members are each at a different stage of understanding hence my remark. But we can all grow by watching and if you wish participating.

Yes its all a lot of fun and you will serve yourself well by doing some logical hands on stuff. But remember to use your ears, what you see is not always what you get with this stuff, even drivers have their own personalities!

[boputnam]

...most members are each at a different stage of understanding...

Uh, yeah - each member IS at a different stage in everything. I don't understand the point of your prior post, or of this one - they are each redundant.

[Ian Mackenzie]

Uh, yeah - each member IS at a different stage in everything. I don't understand the point of your prior post, or of this one - they are each redundant.

Oh, The point is you learn by doing and by all means model and measure it but try and listen it at each stage of development, science ain't the whole story with audio!

All redundant now

Ian

[4313B]

Oh, The point is you learn by doing and by all means model and measure it but try and listen it at each stage of development, science ain't the whole story with audio!

All redundant now

Ian

It is redundant. We've gone over it time and again since this forum started.

Here's a thought, and I'm just tossing it out here for consideration. How about we deal with the topic of this thread - 2123H vs 2122H in a 4343 monitor. Let's start over?

Anyone have the experience of using the 2123 instead of the 2122 in the 4343 monitors?? Aside from the obvious efficiency difference any suggested changes to the network? sub...:0)

The 4343 used the 2121. The 4344 and 4345 used the 2122. Which system are we discussing?

I'll start off with one of my favorite lines from JBL - "Won't work." Very common answer. Let's discover why? Or if it's even a reasonable answer. There, I've thrown down the gauntlet. You guys figure it out.

[4313B]

As soon as I can I am going to lay my hands on a pair of these 2123H's and give them a go.

Ok, that's a good start. Which system will you be trying them in?

[Ian Mackenzie]

I can see your point and I agree, that is why when I did a search I found this thread with some useful stuff. There are other threads too, it needs to be put somewhere where those who need it can find it!!

Here's a thought, and I'm just tossing it out here for consideration. How about we deal with the topic of this thread - a 2123H in place of a 2122H in a 4343 monitor. Let's start over


I think this would be the most useful for the majority.

Ian

[Ian Mackenzie]

Ok, that's a good start. Which system will you be trying them in?

In may case initially the 4345 (with some mods) but ultimately a 4344mk11 clone.

In any case as this is a technical forum I suppose any mention of non standard drivers in a JBL design makes it DIY subject matter and that is probably where this thread should be.

Ian

[Zilch]

Until last week I did nothing. The result was good but not perfect.

[4313B]

Thanks Zilch! That's splendid!

[Guido]

It was as it was

[Tom Loizeaux]

If we are talking 4343s, I believe the foam-surround 2121 is the driver to use because it reaches down best to meet the woofer. As I recall the 2122 and 2123 don't go down quite as low.
Is this correct?

Tom

[4313B]

If we are talking 4343s, I believe the foam-surround 2121 is the driver to use because it reaches down best to meet the woofer. As I recall the 2122 and 2123 don't go down quite as low.
Is this correct?

Tom

Thanks Tom.

From http://www.audioheritage.org/vbullet...t.php?p=135258

The 4343 used the 2121. The 4344 and 4345 used the 2122. Which system are we discussing?

From some of my ancient posts - I'll leave it to others to run the curves to see which goes deepest.

The published xmax on these drivers:

.060"
.120"
.100".

All three have a 0.280" top plate.
All three currently have a moving mass of roughly 26 grams.

The 2121 has a voice coil winding depth of 0.280"

The 2122 has a voice coil winding depth of 0.180"

The 2123 has a voice coil winding depth of 0.420"

They are not interchangeable... Yeah, that's what I said then and I was paraphrasing a JBL engineer so let's see if it's true. You guys try them and report your findings.