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boputnam
06-01-2003, 10:48 AM
Can we Poll the Peers here, and get some dialogue on experiences with the WinISD freeware?

1) Does WinISD produce an accurate representation of woofer response?
2) What T-S parameters are the most critical and are the plots most affected by (besides Box Volume)?
3) WinISD does not seem as sensitive as I would have suspected to port area. True, or am I not observing the effect correctly?

The attached plot of the 128H (green) and LE14A (white) transducers in identical 93.8 liter vented enclosures yields probably indistinguishable responses. Is this result reasonable? Is it correct?

4313B
06-01-2003, 11:16 AM
What was the tuning frequency of the 93.8 liter enclosure?

boputnam
06-01-2003, 11:35 AM
WinISD auto-input 35.49Hz (LE14A) and 34.02Hz (128H).

I am a virtual novice on this freeware...

Robh3606
06-01-2003, 11:52 AM
1) Does WinISD produce an accurate representation of woofer response?


Well I can say I have gotten very good subjective results but I have not measured asside from what I see in room on my RTA. There is at least one other JBL driver combination that does that. The 2035 and 2226 will do damn near the same thing even with the same tunning. They are interchangeable in dual woofer thearter bins. As I am sure they were designed to be.

2) What T-S parameters are the most critical and are the plots most affected by (besides Box Volume)?

Good question can't wait to see the answers

3) WinISD does not seem as sensitive as I would have suspected to port area. True, or am I not observing the effect correctly?

Not sure what you meen? Are you looking at the port velocity??


The attached plot of the 128H (green) and LE14A (white) transducers in identical 93.8 liter vented enclosures yields probably indistinguishable responses. Is this result reasonable? Is it correct?

Well that depends. If that is correct then obviously the response will be very similar however the LE-14 will probably do better ultimately. I am assuming that it will be moving a lot more air more easilly at lower power levels.

Rob :)

4313B
06-01-2003, 12:18 PM
"2) What T-S parameters are the most critical and are the plots most affected by (besides Box Volume)?"

"Good question can't wait to see the answers"

Yes, very good question! And I must refer you to Don Keele's publication "Sensitivity of Thiele's Vented Loudpeaker Enclosure Alignments to Parameter Variations."

This was presented May 5, 1972 at the 42nd Convention of the Audio Engineering Society under the title "The Vented Loudspeaker Cabinet: A Restatement"

I believe it was then published May 1973 in Volume 21, Number 4 of the Journals.

4313B
06-01-2003, 12:19 PM
Here's what I get with Bass Box 6 Pro:

I don't usually use Winspeakerz anymore but if you insist I can run them in that as well.

boputnam
06-01-2003, 12:24 PM
3) WinISD does not seem as sensitive as I would have suspected to port area. True, or am I not observing the effect correctly?

Not sure what you meen? Are you looking at the port velocity??

The default 0.102 m diam for each yields 0.07 mach. Altering the diam changes the mach, but the response curve is not visually changed. I'm guessing this is a guide to minimum acceptible diam to avoid excessive mach (bad). I had intuited that modifications to port diam would affect the response curve, but perhaps not.

I agree that I would expect the LE14A to outperform for exactly that reason, but would it be audible? The response curve suggests "not meaningfully".

And, I should add that I too have had VERY good results consulting the WinISD curves - but my only RTA is my ears...

4313B
06-01-2003, 12:28 PM
"Well that depends. If that is correct then obviously the response will be very similar however the LE-14 will probably do better ultimately. I am assuming that it will be moving a lot more air more easilly at lower power levels."

Overall, the 128H is a lower distortion transducer than the LE14A with lower power compression as well. The LE14H as used in the final version of the L220 is the same era as the 128H. It is true though that moving the greatest amount of air with the least amount of effort is a desirable goal...

4313B
06-01-2003, 01:06 PM
Using a 2235H -

WinISD Beta 0.44 wants to put it in a 3.34 cubic foot volume tuned to 32.63 Hz by default.

WinISD Pro Alpha 0.50a6 wants to put it in a 3.418 cubic foot volume tuned to 32.63 Hz by default.

Bass Box 6 Pro wants to put it in a 3.391 cubic foot volume tuned to 29.34 Hz for a default "High Fidelity" application. Where "High Fidelity" is defined as maximally flat. This is with damping turned off meaning acoustic fill will have no bearing on the results.

By default, Winspeakerz wants to place it in a 4.15 cubic foot volume.

Gary Margolis' and Richard Small's old "Natural Flat Alignment" wants a 3.34 cubic foot volume tuned to 31.8 Hz.


I've personally had very good results using WinISD and excellent results using Bass Box 6 Pro. One of the things WinISD can't do is inform you about mechanical limitations of transducers when tuning very low.

boputnam
06-01-2003, 01:50 PM
Thanks. Exellent dialogue.

Helpful to know my WinISD results are reproducible. I'll keep posting any curious observations, and will check into BassBox 6.0, too.

Robh3606
06-01-2003, 04:36 PM
Hey Rob

"Overall, the 128H is a lower distortion transducer than the LE14A with lower power compression as well."

I have a 128H-1 and it is a really nice sounding driver. I have a 129H too hoping I could use them as a pair, Well we will see on that. Is the lower power compression because of the ferrite??? The larger 4" coil doesn't help equalize the differences?? As a matter of fact all things being equal would a larger coil help minimize the power comperession because of better heat dissipation?? Is it more dependant on the alnico??

Rob:)

4313B
06-01-2003, 06:34 PM
"I have a 128H-1 and it is a really nice sounding driver. I have a 129H too hoping I could use them as a pair, Well we will see on that."

If you ever want to send me that 129H so I can measure it feel free :)

"Is the lower power compression because of the ferrite???

The ferrite structure is a larger heat sink.

"The larger 4" coil doesn't help equalize the differences??

Not for the overall drop in distortion between the 128H and LE14A.

"As a matter of fact all things being equal would a larger coil help minimize the power comperession because of better heat dissipation??"

Yes. A 3-inch coiled LE14, if it existed, would exhibit greater power compression than the 4-inch coiled LE14A or H.

"Is it more dependant on the alnico??"

Only in the amount of heat sink material. When JBL moved from alnico to ferrite Pe figures approximately doubled in most instances.

Don't forget that the ferrite assembly also has an undercut pole piece and flux stabilizing ring. A 128A (alnico V) has less than 1% second harmonic distortion at 100 Hz with 10 watts input. A 128H (conventional ferrite) exhibits ~ 2% second harmonic distortion and the 128H we all know and love (SFG ferrite) exhibits ~ 0.3% second harmonic distortion.

Here's something that may be of interest:

Robh3606
07-14-2003, 06:36 PM
Thanks Rob

I always wondered about the distortion levels in the alnico's. So SFG was a significant improvement across the board.

Rob:smthsail:

boputnam
07-14-2003, 07:26 PM
That's why they make such a startling improvement when swapped into the 4312's. I get it... :thnkfast:

Whoa...

John B
07-15-2003, 03:05 PM
I have LE14H-1s in a pair of 240Ti's. I have LE14As in L220s, L101s, L55s and S99s. I have various 12 inchers in 120Tis, L112s, L166s and L100Ss. Call me stubborn but Iíll take the LE14s, A or H, over any of the 12s.

4313B
07-15-2003, 03:34 PM
Interesting John. So you like the LE14A over the 128H eh? (It seems the LE14, in any form, is G.T.'s favorite transducer and I hear rumors he's fought with Marketing for years to keep it around)

I can easily see why one would like the LE14H-1 so I don't have to be "sold" on that one :) I would like to snag a pair of LE14H-3's to try out.

Just for grins, have you ever tried the LE14H-1's in the L220's with the PR's? :)

Robh3606
07-15-2003, 04:28 PM
Hey Rob

That interesting. When I was looking for a frame drawing for the LE-14A I called JBL Pro. I was talking to the tech about it and he told that for one of Greg's aniversary years the went out and got an LE-14 frame Gold plated to give him. Don't know for sure if it's true but it seems fitting based on your last post.

Rob:)

John B
07-17-2003, 06:56 PM
I thought of swapping the drivers in the 240Ti and L220 but never tried it. I will say that the sound of the bass of the 240Ti is closer to the L55, L101 than any are to the L220. I just got some L150 cabinets, I am curious to see if the 128H in a PR would sound more like the L220 than L112. I am still debating what mid and tweeter to use in them. I could go original Ė LE5-10 & 033. Or semi L212 (similar network) - 2105 & 066. Or 104H & 050 (probably require network changes)

When I hit the lottery and get some PS1400 I let you know what I think of them. Of course you canít trust my opinion Ė I like alnico V speakers too.

4313B
07-17-2003, 08:34 PM
"I like alnico V speakers too."

Me too, specifically the 124A and 136A :)