thiele small parameters of RE MT series drivers and SPL theory

[thadman 10+ year member]

I was just curious if anybody knew the thiele small parameters for REs MT series drivers. They seem incredibly popular with the SPL guys and I wanted to model them in WinISD.

im not an SPL guy by a longshot, but I have a theory that may help people improve their SPL scores.

(I would love everybody to comment, but remember this is just a theory and i have no expertise in the SPL field)

#1 install the subwoofer in any box and measure the frequency response of the driver within the vehicle

#2 remove the subwoofer and box from the vehicle and measure the frequency response of the driver close to the cone of the driver outside the vehicle in a very large area

subtract the outside response from the vehicle response and you get your room gain

#3 You can then easily design a box that will exploit that certain frequency

voila...you're done. You may yield a few extra dBs or maybe a huge gain, you'll have to test for yourself.

Click to read more...

 

[bigbassman Premium Member]

the peak frequency comes from the most efficient working point of the enclosure / vent / driver...

most vehicles boost from the corner frequency down at 12db/octave, and don't have any large response peaks or dips..

doing semi-echoic and non-echoic testing has been used some in the past.. with lacking results for SPL use..

good to see somebody thinkin though //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Loyd L.

 

[thadman 10+ year member]

well regardless, does anybody have the thiele small parameters for any SPL geared drivers (especially the MT)?

I dont think my theory would hurt, if anything it'd help you figure out when room gain kicks in.

 

[bigbassman Premium Member]

here's data on an older model DD 9900 15" dvc 3 ohm

Manufacturer: Test data

Model: DD 9915 dvc 3 ohm

Filename: 9915TEST.UNT

Speaker type: Bass

Sd: 860.00 cm^2

Vas: 71.01 l

Cms: 6.86e-05 m/N

Cas: 5.07e-07 m^5/N

Mmd: 285.53 g

Mms: 299.80 g

Rms: 23.05 Ns/m

Fs: 35.1 Hz

Bl: 21.21 N/A

Re: 1.70 ohm

Le: 1.88 mH

Qms: 2.87

Qes: 0.25

Qts: 0.23

Pmax: 1500.0 W

not allowed to release data on the MT.. sorry..

Loyd L.

 

[thadman 10+ year member]

why are the MTs thiele small parameters a secret? It would be very easy to measure them yourself if you had the driver in your possesion and a dayton woofer tester kit, so how could they expect to enforce it?

do you have any suggestions of what they might be...in a PM?

 

[djman37 5,000+ posts]

why are the MTs thiele small parameters a secret? It would be very easy to measure them yourself if you had the driver in your possesion and a dayton woofer tester kit.

so that's what the woofer tester II does?!?!!

 

[bigbassman Premium Member]

why are the MTs thiele small parameters a secret? It would be very easy to measure them yourself if you had the driver in your possesion and a dayton woofer tester kit, so how could they expect to enforce it?
do you have any suggestions of what they might be...in a PM?

I was given information through RE, under terms of an NDA I signed several years back... to my knowledge, the data on this particular driver was not made public domain.. therefore.. I can't post it..

don't like it? buy one and test it.. not putting my *** on the line for anyone..

Loyd L.

 

[thadman 10+ year member]

LOL...the description was pretty forward I thought

If you are building a speaker, why waste your valuable time calculating "optimum" enclosures that are based on specs that can vary by as much as 30%? With the Woofer Tester 2, you can accurately measure the parameters of your specific drivers from the comfort of your own home. The complete process takes just a few minutes, and provides easy-to-read results that you can print and save. But it's not just for woofers-- the WT2 accurately measures impedance and phase from 1Hz - 20kHz, allowing it to measure midranges, tweeters, inductors, crossovers, and even speaker cables.

Specifications: Includes USB cable, test leads, calibration resistor, and software. Measures Fs, Qms, Qes, Qts, Vas, BL, Re, Le, Mms, Cms, SPL, and more. Compatible with Windows 98SE, 2000, ME, and XP operating systems with an available USB port. Hardware box measures 2-1/2" x 2-1/2" x 1".

 

[thadman 10+ year member]

sorry...wasnt aware that you had a contract with RE.