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Guido
05-07-2008, 03:15 AM
This goes out to the transducer experts.
Subwoof, Edge, 4313B, Gordon etc.

What will happen if I aquaplas a C8R2226 cone before dropping it into a 2226 basket? No mods planned with the spider or surround. Just 40 grams more.
Yes Yes, I already have the C8R2226 and will just try it. But I would like to discuss if it makes sense to have a heavy cone with a firm suspension.

e.g. the ME150 has a heavy cone, a very stiff spider and also a stiff surround due to the aquaplas on the foam. It is a nice transducer....

What do you think?

Hofmannhp
05-07-2008, 04:37 AM
What will happen if I aquaplas a C8R2226 cone before dropping it into a 2226 basket? No mods planned with the spider or surround. Just 40 grams more.
Yes Yes, I already have the C8R2226 and will just try it. But I would like to discuss if it makes sense to have a heavy cone with a firm suspension.
....
What do you think?

Hi Guido,

may I add a question to your's...
I mention about to do a test with a 2226H with a change of the fabric surround to a foam surround and maybe with an additional mass ring.
The voice coil depth of the 2226H is about 19mm and also the xmax is near the 2235. Spider maybe the original one (a little more stiff)
Have you tried this?

Would like to measure the TSP of this part.

HP

Guido
05-07-2008, 04:45 AM
Hi Guido,

may I add a question to your's...
I mention about to do a test with a 2226H with a change of the fabric surround to a foam surround and maybe with an additional mass ring.
The voice coil depth of the 2226H is about 19mm and also the xmax is near the 2235. Spider maybe the original one (a little more stiff)
Have you tried this?

Would like to measure the TSP of this part.

HP

Indeed I'm looking for a 2235 replacement ;)
The 2226 spider is a bit stiffer. It's a cupped spider so using a 2235 flat spider creates a VC offset (already tried this)
It isn't easy to change the cloth surround. I might be inclined to try this but then we have a stiff spider with a foam surround which makes things even more complicated :p

If I try it I'll of course publish T/S parameters. No question :)

subwoof
05-07-2008, 07:37 AM
JBL actually did that scenario with the automotive GTI series. The 1500GTI has a paper so heavy and thick you could go to batting practice with it. I have used them with good success in close-in stage monitors that are limited in size.

The basket is the same as the 2226. However the ME150 uses the *2227* motor with it's slightly deeper gap.....

Buried in my woodshop ( and I will be there in an hour ) is a NOS recone kit for an 8 ohm GTI1500. I will drag it out and send photo's.

If I had to "reinvent" the wheel on a budget, and have a powerful LF transducer, this speaker OR 'plassing a 2226 would be the choice.

Not everyone can afford the 5 mile deep ND monsters...:)

sub

Guido
05-07-2008, 08:32 AM
Hi Sub

I already thought about using a 1500GTI Kit. Actually one of my 2226 baskets is a 1500GTI basket.
2 probs
1st the 1500GTI is a 4 ohm transducer
2nd the driver should go up to 800 Hz. I'm not sure how the 1500GTI handle this.

Oh yes, the ME150 has a much better magnet structure. But man are they rare :(

Do you know one of the ND Monsters that can be used in the 2235 "direction"?

subwoof
05-07-2008, 10:10 AM
The GTI1500 was available in both 4 and 8 - the 8 is a rare puppy indeed.

You didn't mention the range. I thought you were looking for a sub transducer based on the tweaks.

Here are some pics.

One is the C8R1500 kit with a 2206 coil on top of it - the spiders, depth, spacing, etc are identical. Also is a close up of the coil ID. Note that it says 2226H on it - but unsure if that is for the coil/former or the entire assembly ( albeit a different build ). I don't have a new 2226H to compare it to here.

sub

Guido
05-07-2008, 11:09 PM
Thanks for the pics sub!

Yeah I need it up to 800Hz.

Come on guys, these technical topics made this forum interesting. I'm glad for every input here.

Sub, stay away from this Red Bull Drink. Beware, it's Austrian;)

Hofmannhp
05-07-2008, 11:43 PM
Thanks for the pics sub!
Yeah I need it up to 800Hz.
Come on guys, these technical topics made this forum interesting. I'm glad for every input here.
Sub, stay away from this Red Bull Drink. Beware, it's Austrian;)

Hahaha,

I recognized it too Guido,....it's the only way he can survive long JBL assembling nights I guess.:D

Indeed a very interesting thread this one here.

Guido....I have one 2226H without cone on my shelves, ready for a try with different ideas.
Thanks sub for the pics. This confirmes my project targets . As I read in other postings here, a mass ring seems not to be a good idea, though I prefer to get a similar mass refering to the 2235.
It will be very nice to know how the fres of 40Hz is affected by:
- foam edges versus fabric edges.
- mass ring or not
- aquaplasing or not

HP

pos
05-08-2008, 01:01 AM
In my understanding softening the surround/spider or increasing the moving mass will both lead to a lower Fs, but the second option will compromise the behavior of the driver in the mids more than the first one. Does it make sense?

Hofmannhp
05-08-2008, 01:58 AM
In my understanding softening the surround/spider or increasing the moving mass will both lead to a lower Fs, but the second option will compromise the behavior of the driver in the mids more than the first one. Does it make sense?

Hi Pos,

your'e right, but lowering the fres is more difficult then to handle the mids I think. The mids can easy be influenced by the crossover.

HP

grumpy
05-08-2008, 07:27 AM
what it the application/intent?

you can adjust tuning and trade mid-band efficiency for more output (up to physical limits)
in the lower bass region... Same as with 2234->2235. Shows up easily in modelling
tools... even WinISD. Fs moves to 34Hz (modelled as -large- closed box).

Whether other parameters will change, or the coating will survive punishing drive
levels on the 2226 cone is more than I know.

Guido
05-08-2008, 07:42 AM
what it the application/intent?

As written, 2235/2234 replacement with VG technology

grumpy
05-08-2008, 08:02 AM
additional group delay on the low end, about same efficiency once you adjust EQ
slightly to match, maybe 2dB more available output (excursion limited depending on
tuning), faster rolloff above several hundred Hz... but then you've already modelled
this... yes? Then, there's the "unexpected" stuff :) ... resonances, terminations, other
changes in "timbre". It will be an interesting experiment.

Joe Alesi
08-16-2008, 02:35 AM
This goes out to the transducer experts.
Subwoof, Edge, 4313B, Gordon etc.

What will happen if I aquaplas a C8R2226 cone before dropping it into a 2226 basket? No mods planned with the spider or surround. Just 40 grams more.
Yes Yes, I already have the C8R2226 and will just try it. But I would like to discuss if it makes sense to have a heavy cone with a firm suspension.

e.g. the ME150 has a heavy cone, a very stiff spider and also a stiff surround due to the aquaplas on the foam. It is a nice transducer....

What do you think?

Hello Guido,

I Just saw this thread when searching on 2226 drivers. I thought I'd post- better late than never.

Interesting idea- a souped up 2235!!..well 2234..ish
The 2226 has an fs=40Hz and a moving mass of 98 grams. If you add 40 grams to the moving mass the fs will clearly go down. What will it go down to? I think it will be something like 33 Hz.

This is based on treating the speaker as a simple spring mass system- a reasonable first order approximation, which ignores any 2nd order terms like damping.

PS: Thanks again for the avatar - still using it!

Another idea (not as sophisticated/high-performance as aquaplas- take 40 grams of lead shot (good because high density) (BB's) and place them evenly around the annular valley formed between the dutcap and the cone. Then glue them in place in a sea of epoxy. I saw this in an old "Speaker Builder" article in a subwoofer application. Only problem would be all that mass in that concentrated location would change the cone's breakup and resonant modes in possibly undesirable ways...an idea to try anyway if you are flush with cones and want to experiment. You could even try blu-tak to get a quick (until it falls off) idea of what adding a certain amount of mass will do.

Best
JA

Zilch
08-16-2008, 10:56 AM
http://audioheritage.org/vbulletin/showthread.php?t=4215

Hoerninger
08-16-2008, 11:09 AM
Some TSP can easily be recalculated:
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20%281977-05%20AES%20Preprint%29%20-%20LF%20Horn%20Design%20Using%20TS%20Paras.pdf ,page 17.
(RE, Bxl, CMS, RMS, QMS, VAS unchanged.)

Given speaker (2226):
MMS = 98 g
FS = 40 Hz
QES = 0,33
QTS = 0,31

new speaker (2226Guido)
MMSn = 139 g
FSn = 33,7 Hz
QESn = 0,39
QTSn = 0,36
____________
Peter

4313B
08-16-2008, 11:32 AM
Which probably isn't what you really want. You probably want to keep that Q low ( If not then just use a W15GTi :p They're all over the place. )

I assume you aren't satisfied with the low end of the ME150H, 1500FE or 1500AL? The only transducer I know of that JBL has left which exhibits the bottom end of days gone by is the LE14H-3.

Guido
08-17-2008, 11:35 PM
I assume you aren't satisfied with the low end of the ME150H, 1500FE or 1500AL?

No No

it's not that.

I just still looking for a 2235 substitude made with easily available JBL components.
Those 2225 cores start to get rare here as I already converted them all to 2235/2234 :D

GordonW
08-22-2008, 06:58 AM
If the driver needs to go up to 800 Hz, you may find that a mass ring may work better than aquaplas, since it will affect the high-frequency behavior of the cone less.

IIRC, this is why JBL went to mass rings on the 2235 instead of heavy cones... better HF behavior...

And, IME, I wouldn't be too concerned with a Qts of .36. That's not too high... especially considering that the Qes is still under .4, also. If it was over .4, I'd be starting to get a bit concerned. A lot of very good speakers have had Qts and Qes figures in the .3 to .4 range...

Regards,
Gordon.

4313B
08-22-2008, 07:35 AM
If the driver needs to go up to 800 Hz, you may find that a mass ring may work better than aquaplas, since it will affect the high-frequency behavior of the cone less.Plus it takes a ton of the stuff to get any kind of decent mass on large cones. I'm on my third coat now on a 2235H and I'm still 10 grams shy. The cone stiffens up real nice though.
IIRC, this is why JBL went to mass rings on the 2235 instead of heavy cones... better HF behavior...The aquaplas tends to flatten out the response curve which may or may not be what someone desires in the design.

GordonW
08-22-2008, 10:36 AM
The aquaplas tends to flatten out the response curve which may or may not be what someone desires in the design.


From what I've seen, the aquaplas flattens out the response, but the decay time (as indicated by the waterfall plot) gets a little longer, before things totally settle down. More stored energy in the extra cone mass (with more opportunity to move in "random" directions, compared to a pretty-much-rigidly-fixed mass ring). The decay drops faster at the beginning, but the "tail" is longer before it completely goes away (it's more "squished" downward right after the impulse, and outward from t=0, on the plot)

Plus, extra stiffness can result in "ringing" modes, where there weren't any before. Fortunately, the extra damping of the aquaplas tends to absorb a lot of these, so it's not as much of a problem as it would be, say, if you used something like epoxy coating... but with any stiffening agent, you get some effect like this.

So yes... it's a trade-off... bandwidth and rise/fall time vs. damping and response flatness...

Regards,
Gordon.