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Quentin Jarrell

Ethos sample 12" T/S parameters

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Klippel results are in. I was able to get full small signal results. (ones used when building boxes). But was unable to get complete large signal parameters because their 5,000 watts RMS amp couldn't push it to XMECH. I'll have graphs and parameters up tonight.

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Current small signal parameters are as followed. I plan on doing a little modifications on the motor's internals that will decrease BL a tad. I got a 70% bl xmax of 27.8 so I'll be making the coil a few mm longer to get it to 32 mm xmax. So finial parameters will change but I really just wanted to see how close SpeaD was to Klippel and to verify that the Magnitizer used was fully charging the magnets. For right now I'm happy with the motor and will order the production run tomorrow.

RE 1.5

FS 34.36 HZ

MMS 347.36 G

MMD 341.503 G

CMS .044 MM/N

KMS 22.69 N/MM

BL 16.96

MOTOR FORCE FACTOR 191.76

QMS 7.439

QES .463

QTS .436

VAS 15.03 L

SD 490.87 CM^2

XMAX 27.8MM

LE 1.79 MH

SPL 85.3 DB

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Is the Ethos one of the MMAG motors or standard overhung?

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Is the Ethos one of the MMAG motors or standard overhung?

Standard overhung. I will not be offering any MMAG with standard baskets and softparts. The geometry is not good enough for a ultra high xmax or SQ sub. In my opinion anyway.

The problem is the clearance between the spiders and body. Because the spider pack is so thick the cone body rides on it causing the coil to offset. This sub for example sees an offset of 6mm. In order to correct it I'll be offseting the coil 6mm. You notice this a lot on big 10'' subs Not a big deal and no one one would even know if I didn't say anything but I don't thing it's acceptable on a "high end" line like the MMAG will be.

Also I don't want to design a motor around a cone or basket. Nor do I want to stick the same motor on a 12 as a 10 or a 15. The MMAG will be done right. I have set goals. For example (numbers are rhetorical) I want a 12" sub to handle 2,500 rms, with 70mm one way xmax that will have an f3 of 27hertz in c4 enclosure of 1.5 cubic feet. So every part for that particular sub in mind from the motor to handle the moving mass down to the correct geometry and weight of the dust cap.

Edited by Quentin Jarrell

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Is the Ethos one of the MMAG motors or standard overhung?

Standard overhung. I will not be offering any MMAG with standard baskets and softparts. The geometry is not good enough for a ultra high xmax or SQ sub. In my opinion anyway.

The next driver with the mmag motor is going to have the increased Sd over traditional cone/surrounds, correct?

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Here's the motor in case people missed it. I wasn't happy with the durability of the black paint so I'll be going with black chrome or regular chrome dependant on price. I will also be adding a 10mm high chamfer and putting in (4) 10mm x 10mm cooling vents down the pole similar to what JBL started doing a few decades ago. I'm still gathering final prices but the 18" will be at or right under $390

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ON A 18 BASKET

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ON A 10 BASKET

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PURE COPPER FLATWIND COILS

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CSC_0143.jpg

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voltagecurrentgraph.jpg

Above is a voltage/Current graph from the large signal testing done on the 12" sample. Testing was done free air on a Klippel machine. The measure Re of the sub was 1.5 ohms

(yellow) Urms = rms voltage applied

(blue slashed) Upeak = peak voltake applied

(gray) Irms = rms current

(gray slashed) Ipeak = peak current

The bottom is the time in seconds that the testing was done. Using ohm's law you can calculate the amount of power that was giving to the sub FREE AIR during the testing

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The below graph is the voice coil displacement and correlates directly with the power graph above.

Green= physical coil movement

Blue = calculate instantanious center of coil's in and out amax value

yellow= calculated xmax if from a true zero center

voicecoildisplacement-1.jpg

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This is the actual Re as measure during the testing.

reresistancegraph.jpg

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Looking forward to the finished product. Thumbs up Quentin.

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Just stumbled upon this but I really enjoy analyzing, to the best of my ability, the FEA results and testing results you post during your the design process if your subwoofers. I am about to graduate from LSU as a mechanical engineer. I spent many hours last semester designing a structure for our senior project using Solidwork's FEA software so I can appreciate your work.

What software did you use to get the above testing results?

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The above parameters and charts are real world testing on the actual sample via a Klippel Analyzer. For modeling I use a few Programs. To figure what's needed for a particular driver I use SpeaD and Reverse SpeaD. For example with the Ethos 12" I wanted a sub with 30mm one way xmax that would work in a 2 cubic foot box tuned to 32 hertz with a 25-30 hertz f3. Reverse SpeaD will tell me the mechanical parameters along with the necessary motor force to achieve this. Then using that information I use SpeaD to design the motor. Once I have the motor parameters designed I use FEMM (2d magnetics modeler) to verify saturation and motor force, and heat saturation and flow with the help of Mathcad. Once that's done I use Infolytica's "Magnet" (3D software) to design things like motor cooling. This software allows you to input parameters of the softparts and power, ect to get a good idea how the motor will operate in the real world. When it comes to soft parts I use LoudSoft's FineCone, which I haven't applied yet. None of my custom softparts will be available till late this year.

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