Here is a guide of some little things that are helpfull to play with that not everyone knows about when using winisd.
Let's do some work
Mine? Well, I i'll be using a custom 10" Power Acoustik Fubar Driver, a subwoofer.
Well it's a Subwoofer and I am going to focus on the general range that subwoofers tend work with.
Decent sounding bass that is decently loud and "hits". An average setup, not competition burping/music, but good sounding daily music, a middle compromise of decent SPL and alright sound quality. Also most important is that it's for a vehicle, not home.
Very Important, Subwoofer paramaters
TS Paramaters, or small signal paramaters which I got from self testing with a woofer tester
Series Wired Dual voice coil
Re = 6.8190 ohms (Nominally 8ohms)[D4 coil]
Fs = 43.2323 Hz
Zmax = 71.4393 ohms
Qes = 0.6007
Qms = 5.6927
Qts = 0.5434
Le = 4.6287 mH (at 1 kHz)
Diam = 213.3600 mm ( 8.4000 in )
Sd =35753.2799 mm^2( 55.4177 in^2)
Vas = 20.8026 L ( 0.7346 ft^3)
BL = 19.0994 N/A
Mms = 118.3046 g
Cms = 114.5568 uM/N
Kms = 8729.2910 N/M
Rms = 5.6451 R mechanical
Efficiency = 0.2629 %
Sensitivity= 86.2163 dB @1W/1m
You don't necessarily need ALL of them but it's ALOT nicer to understand the driver better.
We should all know the mandatory paramaters already, the Qs
as i call them, the vas
, and the Fs
I will explain later but i prefer chebychev for this particular response
Here is our Fubar without Le Sealed, 1.100 cubes NET:
This is whithout Le AND without cabin gain, F3 of 58hz
Now, with Le
Added Le of 4.63mH Creates that hump above the red line near the newly found Lowpass rolloff of the subwoofer. Le is the coil's self-inductance at 1000Hz. Inductors hate changing direction of current so the higher you go in frequency, the more reactance there is, bascially, which is why subwoofers can't play high very well, if at all.
Next, Cabin gain simulation
This isn't right on the money, just a mathamatical trick people use to key cabin gain into their response graph.
You goto the eq/filter tab on you driver settings, click add, etc
I am lazy so read here for settings and what they are for: http://linearteam.proboards.com/inde...lay&thread=283
That link is one of the first writeups i read about it.
Look what we have with my example without Le
in a sealed box for my 10" Fubar
with a typical 12db/octave "predicted cabin gain" Via linkwitz transform EQ simulation added.[Note, of-coarse this isn't a precise simulation of cabin gain but it is just like imagining it in your head, but it excludes an additional gain around 25hz and down that is another part of cabin gain]
But, now let's see how it looks with Le
I would like that.
Well, i will explain a little
What it does is add an imaginary EQ to boost the low end, pretending as if a 12db/octave slope of boost was there like your typical cabin gian theory goes, but in reality cabin gain will be a little different and there is more boost around 20-30hz and down in vehicles. In the settings use .707 for q0 and Qp, 15hz for fp, and f0 is your cab's resonance frequency.
'Advanced' setting for system loss under the box Tab
What does this thing mean in the box tab at the bottom? looks complicated? Naw...
Ql This is the box leakage, high is tight and low is leaky, 5-10 is average, default is 10.
Qa The Box absorption losses, lower is more loss, adding pollyfill lowers it.
Lowering it reduces peak response above tunning and and reduces impedance there too which is bad for a sealed box if it is too lossy. default is 100. Having 5 as a value is like stuffing the crap out of your box with polly fill. With a ported box you will see the first Resonance, or the right impedance hill lower.
Qp Port loss, increasing power to the sub will make this worse so it changes with more power and the default is 100, higher makes the box more efficient at tunning.
Having 10 for this value is like having something in the way of the port or bad loading.
Voice-coil Temp rise
Under drivers tab, you will see this, click on K until it changes to C and type in what you think your sub is getting too. There is a rule of thumb that a copper coil subwoofer doubles DCR at 200celsius. Don't get this confused with impedance rise, that false assumption that reactance rise is from the coil temp raising! That is so false! It is DCR that raises with added heat which is different then reactance, but that won't be gone into. With the temp raising, your Qts is suppoused to go up and that lowers port loading efficiency and changes response a bit.
Drive Level and excursion
You can change the drive level from the default of 1 watt upto say 500watts, 1000, etc. Then, you can checkout the driver excursion to get an idea how your mechanical power limit may be. You may have to give your subwoofer less power to safely achieve the entire low end beyond tunning, or you can also set your sub sonic filter, ot change the alignment. It's best not to have to change the alignment IMO, and you may also want to avoid the deviation in power handling, it is upto you, the designer.
With the level at 800W, the PEAK to PEAK excursion is about 1.23", the p2p Excursion of the sub is about 1.2".
That is all for rightnow i am busy and may add alot more when i have time. I hope you like it.
600w shows 1.12" P2P, that is good for me for a small motored 10" sub with a .25" Top plate and low density coil.