2216Nd-1 Measurements??

[Robh3606]

Does anyone have any information on the 2216-1nd?? Specifically a measurement?? I am wondering what exactly the aquaplas is doing besides adding mass. I have been :banghead: trying to work some differences out between system voltage drives vs drivers. I was having my own issues with measurements with the 2216nd until I finally got things resolved and a raw measurement of a 2216-1nd would go a long way to see if I got it right. Thanks!


Rob:)

[grumpy]

I assume you're after audio (vs electrical) measurements... (?)
Electrical I can do, if my Smith & Larson WT-2 still works ... and I can find it :o:
Audio would be more of a trick.

[Robh3606]

Hello Grumpy

I found what I was looking for will post the curves latter and they answer a lot of questions for me. If you could run the T/S it certainly would not hurt to have it available on the forum.

Thanks Rob :)

[Robh3606]

Here is what I was talking about. The differences between the voltage drives used in the 4700 which uses the 2216-nd and the 4367 which uses the 2216-nd-1. Looking at the differences as far we know it's a couple of grams of aquaplas to the lower the FS and lower break in time. I was looking for a measurement to compare the 2216 we have on the site and found it in the 4367 White Paper.

If you carefully look at the measurements you can see that the aquaplas is doing more than just adding mass. It is affecting the frequency response by flattening out the rising response of the 2216 above 500Hz as well smoothing out the response and filling in the notch at 200hz. This is exactly where the differences are in the voltage drives.

Based on this they are not equivalent replacements. Good to know if you decided to try out the "new" drivers.

Rob :)

[grumpy]

Used 13.5" as Diam (mid-surround)

Note: Vas/BL/Mms 2216Nd (not -1) EDS shows 140L/18.9/135g. These and Cms are the squishy numbers that can be difficult to measure accurately and consistently. I would consider those parameters listed below as "ballpark", not definitive.

Took several tries to get a clean impedance/phase sweep...with no funny wiggles and resulting in seemingly realistic Vas/BL/Mms values. Ended up resorting to a vertical hold for the initial sweep, and an open horizontal hang for the mass-loaded Vas test (OK, basically between my knees whilst sitting). Never got around to building a custom jig for this. Setting it on the floor or tabletop was not sufficient as the aforementioned values were bonkers.

Also, perhaps note that these units have not (yet) seen active duty. The numbers look OK and repeatable including between two drivers. I'm assuming that the 2216Nd-1 is the 2216Nd frame, coil, and magnet with an aquaplas-ed cone (perhaps the same basic cone) and perhaps an adjusted spider.

The cones have numbers written on the back... I'm guessing it's some measured cone weight after aquaplas application (73.6 and 71.6) but before installation... there really isn't much, maybe a very thin layer in a 2.5" ring nearest the surround, and 1/3 of that nearest the surround is coated with a thin viscous layer. Hard to imagine this adding much weight to the cone...20g doesn't seem crazy. More of a mechanical impedance termination/transition (?).

If something looks out of whack or if there are questions, let me know.
:cheers:

Buffer[1] Vas Ver 7.01
Completed: Tue Jul 14 22:07:24 2020
Drive level 90.000% [3.244 mA]
Sine,LoZP(LV/LA)->Vas,20 pts
;------------------------------------------------------------------
Re = 5.5253 ohms
Fs = 28.6031 Hz
Zmax = 116.6246 ohms
Qes = 0.4082
Qms = 8.2082
Qts = 0.3889
Le = 0.6475 mH (at 1 kHz)
Diam = 342.9000 mm ( 13.5000 in )
Sd = 92347.4431 mm^2(143.1388 in^2)
Vas = 237.8970 L ( 8.4013 ft^3)
BL = 19.5839 N/A
Mms = 157.6664 g
Cms = 196.3697 uM/N
Kms = 5092.4346 N/M
Rms = 3.4521 R mechanical
Efficiency = 1.2814 %
Sensitivity= 93.0949 dB @1W/1m
Sensitivity= 94.7023 dB @2.83Vrms/1m
Krm = 10.782E-06 ohms Freq dependent resistance
Erm = 1.365E+00 Rem=Krm*(2*pi*f)^Erm
Kxm = 8.660E-03 Henries Freq dependent reactance
Exm = 713.618E-03 Xem=Kxm*(2*pi*f)^Exm
;------------------------------------------------------------------
Ftest = 23.546 Hz
Ftest/Fms = 0.8232
Test Mass used = 75.0000 g (Equal to 15.0 nickels)
Test Mass (Ft=Fms*0.90) = 36.983 g (Add -38.017g for Ft=25.743)
Test Mass (Ft=Fms*0.75) = 122.629 g (Add 47.629g for Ft=21.452)

[Robh3606]

Great !!

Thanks for doing it and posting it!

Rob:cheers:

[Earl K]

Yes, thanks Grumpy for shedding some more light on the specs for the 2216nd-1.

The limited application of aquaplas ( you mention ) is really interesting.

Is that aquaplas 2.5" wide strip on the front or back ?

In your opinion, do you think someone already handy with handling woofers speakers, could aquaplas a similar 2.5" wide strip ( onto say, a regular 2216nd ) ??

:)

[grumpy]

Hi Earl, it’s on the back.

I think it would be difficult to accomplish a truly equivalent DIY -1 version for several reasons.

It’s on the back.
There may already be goo (aeroflex 400?) where you would need to put the aquaplas (even if a spray on the front was considered).
Then there’s the overlay of sticky stuff, and I think I recall a different spider was used.
Not sure a spray on the front would perform the same function (conjecture, I have no way to test this).

Not to say a person couldn’t experiment (even virtually, to first order... e.g., put a 2216Nd into winisd and add mass, but that doesn’t cover edge termination and resonances). Could get expensive :) starting with a recone kit would make a lot more sense, but then why not just order the desired kit (if available)?

Photos follow.

[grumpy]

87060
87061
87062

[Earl K]

Thanks for the pics Grumpy!

:)