I hope my post helps
This is a smart phone calculator. It’s proven quite useful
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I hope my post helps
This is a smart phone calculator. It’s proven quite useful
Hi Guys;
I just weighed four new OEM JBL 2234-2235 cone kits.
The cone coil assemblies weight between 94 to 98 grams. The cap and mass ring weigh 42 grams in the little unopened bag they come in.
Average total is 139 grams. No glue. I can’t calculate that.
I hope this helps.
Barry.
The weight of my ( oem 2235H kit's ) dust-cap is 3 grams and the mass ring is 32 grams.
The kit is from @ 2001.
:)
I think within 3 grams is close enough.Quote:
Originally Posted by turnitdown
FWIW the 2234 has an official MMS of 105 grams
Add the official air load MMD is 120 grams
Add the mass ring +35 grams = 155 grams = 2235H MMD
Ian you're using the terms MMD & MMS backwards ( MMS = MMD plus air-load ).Quote:
Originally Posted by Ian Mackenzie
That's definitely not helpful to this thread.
Go look at one of my early links posted in this thread ( to the LoudSpeaker Database ) for a bit of re-education.
:)
I don’t need re education thanksQuote:
Originally Posted by Earl K
there is a typo on the JBL public data
Which states the 2235 MMS as 155 grams -see below)
To re state this
The official JBL TL
https://help.harmanpro.com/thiele-sm...efinitions-(2)
2234 has an official MMS of 105 grams ????
2235 As above. 155 grams
To prove this l did the following:
Note the actual 2234 fs is 23 hertz according to JBL public data :
The QTS is a bit low lower at 0.22
The QMS is also a bit lower at 2
The VAS remains unchanged
According to my TL modelling the 2235H has a MMD of 140 grams
Add the Air load of 15 grams for the MMS of 155 grams (this is confirmed in the TL modelling)
The real difference on a stock 2234 is the mass ring which is 35 grams. It always was and always will be.
Therefore
The 2235 MMD is 140 grams
The 2234 MMD is 105 grams
The 2235 MMS is 155 grams
The 2234 MMS is 120 grams (the JBL official TL data states 105 grams in error)
The air load in both cone is 15 grams. This is calculated from the cone SD and some allowance
The mass ring is 35 grams
The TL equations don’t lie. Have you actually met Neville Thiele. I have.
So l do know what l am talking about.
Mmd is the mass of the moving parts of the driver; the diaphragm, dust dome and voice coil. The diaphragm is the paper cone in a standard speaker. The voice coil includes the former and the copper wire. Most definitions online for Mmd seem to just be copies of each other, citing that the surround and spider are included in the moving mass. A bit of further research has suggested that only part of the mass of the spider and surround should be included, as the outside edge of the surround, and the outside edge of the spider are both glued to the chassis, and therefore DO NOT MOVE.
Mms is commonly used in loudspeaker modelling software. It is Mmd plus the ‘air load’. The air load is the air just in front, and just behind the speaker cone that will tend to move back and forth with the cone. It’s just a few grams of air, but for mathematical modelling of speaker performance, needs to be added in. A larger cone will have a larger air load.
Mms is used to calculate other TS Parameters, such as Qes and Qms.
There is one final significant point with regard to the Mms, and that is the relationship to Fs (Free Air resonance). A heavier cone generally has a lower resonant frequency, a lighter cone will generally have a higher resonant frequency. The other factor in the equation is Cms which is a measure of the suspension compliance. The formula which connects Fs to Mms is as follows:
Fs_Formula
Click here to read more about Thiele Small Parameters: Fs (Free Air Resonance)
We’ve mentioned this before, and just to hammer the point home here, you really, really should be aware now that all driver parameters are dependent on each other. The fact that cone weight, voice coil geometry, magnet strength, cone stiffness all interact and affect each other in both positive and negative ways means that any speaker design always has some compromises. Some might call this optimisation – a driver specifically designed for the best sub-bass response will sacrifice mid and upper bass response.
Consider yourself now educated’…Lol
Ian,
Thanks for demonstrating your complete understanding of the terms "MMS, MMD & Air-Load".
( Now to put it to use ), it would be helpful if you could puzzle-out why ( or offer-up a plausible theory ) why LHF member "patallen" has an OEM 2225H cone kit ( removed intact ) that weighs in at 105grams ( when best guess is that the 2225's MMD should be around 90 grams ).
Here's a pic of his 2225 cone assembly:
https://www.audioheritage.org/vbulle...1&d=1708384271
This "outlier" in measured weight is causing quite a bit of confusion ( from what I see ).
:)
So just to answer myself, 105G for the 2234h moving mass including everithing on a kitchen scale is good enough altough 30hz for self resonance after a moderate break-in period indicate a stiffer suspension (i wont use any technical words anymore so to not trigger the karens)
My old 2225H cone assembly measuring 105G too is probably "too heavy" due to too much impregnated beer and cigarette tar imbeded onto the cone (it stinks like if i where into a 70's rockabilly bar), otherwise it will remain a mystery and is responsible of my confusion.
thanks.
Cool patallen,Quote:
Originally Posted by patallen
Your mystery 2225 recone will remain a mystery ( though FWIW, that rust-colored banding or glueline on the back is much more typical of a very specific generation of the 2226HPL woofer ).
Also, as a continuing mystery, I've never seen a 2225 where the surround became unglued like yours has ( it looks like an adhesive failure to me ) & I've used 2205//2225's since the middle 1970's ( starting with the Alnico model ).
Back in the "Golden-Years" of JBL warranty claims here in Canada, I'm confident that "Gould-Marketing" would have accepted a claim ( from a qualified reconer ) for a free recone kit on your behalf.
:)
Any possibility some one tried to repair that? Every JBL cone I have has a black adhesive band. I am no expert but how thick is that brown stuff? It looks like is has an edge. Or re-edge it?
Just a thought.
Rob :)
impossible to tell, i bought it from ebay as is to be reconed (dead). it is not thick at all. just normal and dry i would say, compared to others in hand.Quote:
Originally Posted by Robh3606
i have 6 other 2225h and some J, gray basket and black, dates codes from 1984 up to 1990, all of them have this brown marking visible on the back of the cone where the suspension meets the cone.
They comes from all over the planet from various sources. you can see one of them other 2225 on the picture of the cone assembly. same color. i doubt it is a coincidence.
Hi guys;
I wondered the same. I bought an E140 that had been re-edged once. It looked about like that.
Barry.
Might have been a previous re-cone and the cork wasn't completely scraped off.
Hahaha. ..If only it could talk, eh? "..If I have to belt out "Sweet Caroline" one more time.. :cooked:"Quote:
Originally Posted by patallen