I am looking at a speaker which has the 2245H reconed as a 2240H. What is the effect of such a transplant? Is it good or bad? Anyone know the answer?
Thanks
MB
I am looking at a speaker which has the 2245H reconed as a 2240H. What is the effect of such a transplant? Is it good or bad? Anyone know the answer?
Thanks
MB
Restoring the legend, one cabinet at a time
I'm fairly sure that 2245 and 2240 are same cores.
I have 2245 cores that have been reconed as 2240's arriving next week and will let you know how the results are when I have a chance to play them awhile.
Ron
JBL Pro for home use!
A 2245H reconed as 2240H is a 2240H.
Ok, except the foilcal.
As a subwoofer is the 2245 superior? Is it something that if played side by side in the same type enclosure I could hear a significant difference? What does it do to the value of a B460?
Thanks
MB
Restoring the legend, one cabinet at a time
For home use? I'd say yes.As a subwoofer is the 2245 superior?
or feel, ... most likely....hear a significant difference?
Current price of a 2245H reconeWhat does it do to the value of a B460?
These are freshly reconed and have not been broke in yet:
I listed the serial nrs that were used for the 2245 since I wanted to keep both identifiable.
JBL 2240H #24026 2240H #24010
Fs 31.68hz ---31.2hz
Qes .32 ---.31
Qms 7.2--- 6.8
Qts .31 ---.3
Le .87mH--- .87mH
It will take me a few weeks and break them in before they each get their own 8 cubic ft ported cabs for LF duty between 40hz and 200hz.
My room is so small that I don't worry about loading down below 35hz. The living room will not energize with those low notes, but the garage, kitchen and outside will!!!
Ron
JBL Pro for home use!
I see the Qms values I measured with WT2 are higher than the JBL 2240H specs.
Does anyone have ideas on what caused that figure to be off???
Could it be from the voice coil not being in the exact location in the gap???
Or will it decrease upon break-in???
Thanks for all comments/opinions!!!
Ron
JBL Pro for home use!
I guess it’s the foam surround that you find discouraging and ribbon cloth surround reinsures you with easy of mind and conference.
Here is a simulation of a 2245H (green) and a 2240H (red) in the B460 (8ft 26Hz)
group delays are also higher for the 2240H
Hi Ron,
Change in compliance (Cms) will affect Fs (more compliance, lower Fs).
Change in Fs will affect Qms in direct proportion.
So... I'd expect a break-in to increase compliance, lower Fs, ... and therefore Qms.
http://en.wikipedia.org/wiki/Thiele/Small
As to what's 'normal' for a newly reconed 2240, perhaps you already have the
best information.
-grumpy
JBL Pro for home use!
That'll be an interesting setup. I hope the 2235's can keep up
I'd be curious to see how/if the 2240's actually do drop Fs after some use,
...if you have time (and feel like bothering) to remeasure later.
grumpy,
I will be running the JBL 18" as a 2-way with compression driver and horn on top driven by either a single ended (triode-strapped EL34 monoblocks - 6 watt output) or a McIntosh MC-240 tubed amp. The 2235's will get a much larger SS amp to fill in the bottom.
My listening room is very small, so not much wattage required.
I will post results after burn-in when time permits.
Thanks, Ron
JBL Pro for home use!
In a few weeks I'll have a pair of 4 cu ft cabs w/6" dia port 7" long for approx 40hz tuning.
Crossover will be 500hz to 2441 on 350hz Edgar tractix horn with bullet tweeter on top.
I will post when all the goodies come together and get installed.
Regards, Ron
JBL Pro for home use!
POS:
The graph you posted is interesting.
I have a couple of 2245Hs and was told they are not suitable for two-way systems since they cannot play flat much over 100Hz. According to your graph, this is not true, I suppose.
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