How To Use Winisd?

[buggers]

I have tried for a couple years to get winisd to work. No matter what I do it gives me an error. Yes I put in only the perameters that Steve Callas recommends and it still errors out. Is there a tutorial out there with step by step instructions? Thanks.

[brucek]

The tutorial is the Help file. Go to the section on entering new driver data parameters and follow it explicitly and it works fine.

The condensed version is this:

LOAD THESE INTO WIN ISD IN THIS ORDER TO PROPERLY ENTER NEW DRIVERS:
or just follow the Help files. They say the same thing. use TAB after each entry to invoke the auto calculate feature.

1. Mms, Cms

2. Sd, BL, Re (ensuring that you know whether it is specified in series or parallel for dual voice coil drivers)

3. Qms

4. Xmax

5. # voicecoils (default is parallel)

but if Re, BL is specified in serial, then select serial and correct Re, BL that the auto feature messes up. If you have the series values for Re and BL and want to calculate the parallel values - initially perform the following to calculate them and then clear all entries and start at point #1.....
I'll just reprint what the help file says:
If there are several voicecoils, then you must be careful when entering parameters in that case, because many manufacturers give Bl in voice coils in series, because it yields double value for Bl against parallel connection. If driver manufacturer gives Qes, Bl and Cms or Mms, then you can check how Bl is specified. For that, you can enter following parameters to calculate Re: Qes, Fs, Mms or Cms and Bl. Connection mode can be changed by changing the combobox selection. The driver editor then converts Bl and Re values accordingly.

Equivalently, you can check for Bl by entering:

Qes, Fs, Mms or Cms and Re (for desired connection mode).

If you enter resistance for parallel connection and get about half of advertised Bl, then you know, that Bl was specified that way.


So, for example with the SoundSPlinter RL-P18-D4 where they specify Re=6.26 and BL=24.25, this would be two coils in series. You know this because two times 4 ohm is 8 ohms and so the 6.26 ohms is the pure resistive coils in series. If you want to calculate the parallel equivalent use the method I outlined above to first establish that and then clear and start at point #1.... (the answer for parallel would be Re=1.565ohms and BL=11.93070

Get it?

brucek

[brucek]

and also............

There's a decent discussion here on using WinISD.

It shows which parameters are important.

For example, in this quote from that very discussion.

Here is a response that Steven Kephart contributed in another thread, but it can by very useful as an addition to this one. This can help you understand relationships of parameters when you are filling in the driver editor for your subwoofer. You'll see statements like (paraphrased): "Fs is set by Mms and Cms." This gives you an indication that if your spec sheet shows all three of these parameters, use just the Mms and Cms and let WinISD calculate Fs from those values to avoid the possibility of getting an error. If your sheet shows only Fs, then that is what you input.

"Here's a quote from my old boss, Dan Wiggins, that helps explain Theile/Small parameters:

'There are only 6 fundamental physical parameters of a driver:

Re - the DC resistance of the voice coil (often called DCR). This includes the voice coil and tinsel leads. Measured in Ohms.

Le - the inductance of the voice coil. Usually measured in millihenries, sometimes microhenries.

Sd - surface area of the cone, usually measured in square centimeters.

Cms - compliance/stiffness of the suspension, usually measured in mm/N. That is, the suspension will sag X millimeters per Newton of force (there are ~4.5 Newtons per pound).

Mms - moving mass of the driver. Typically measured in grams.

BL - motor force factor of the driver. Measured in Tm (Tesla-meters) or N/A (Newtons per Ampere). I prefer the latter, because it is much more explicit about the force factor - X Newtons of force for every Amp of current you put through the driver (note that 1 Tm = 1 N/A).

and this:

I have gotten an indication from a reader that my wording in the 'Input the T/S parameters' section may lead you to think that you can fill in only a few parameters from your spec sheet and you're good to go. That is not true. You want the driver editor box to be filled out as completely as possible before you save it. Regarding what I wrote in the first paragraph here, you will see that the WinISD Help section on inputting parameters tells you to start with Cms and Mms (both physical parameters) if you have those values available. The reason they did not include Fs should be apparent to you now.

See why it's important to follow the method in the HELP file. Entering the best parameters to allow it to calculate the missing ones is quite important.........

brucek

[Blaser]

Brucek, really helpful as always!!

[buggers]

Thanks Bruce! I have entered the parameters like you said and it appears that the program is holding. I am making a 30 inch diameter Sonosub with the RLP-18 D4, 14Hz tune for Home Theater.
Qts: 0.493
Qes: 0.554
Qms: 4.500
Fs: 21.5 Hz
Re: 6.26 Ohm
Ls: 4.341 mH
Rp: 10.27
Displacement: 0.2 cu ft
Vas: 276 L
Mms: 373 g
Cms: 137.7 u

Bl: 24.25 T*m
SPL: 89.25 dB
Sd: 0.1188 m^2
Xmax: 27.4 mm
According to Winisd I need a 25 CUFT (708liter) box with a 37Inch (93.98 Cm) Length, 10Inch (25.4CM) Diameter Port and according to the sonosub calculator is a 65.5 Inch (166.37) Length sonotube.
Could you check my calculations to see if I have done this properly? Thank you very much.

[Blaser]

Buggers,

704 L and 14 Hz will depend on the power used, if you have too much power with too low a tune, you may exceed the Xmax at higher frequencies than the tuning.... Take care of that.
The volume in WinISD should not be followed exactly as it is. you can check for 600 L also which models quite well with a 16 Hz tune, and still keeps below Xmax with 1000 Watts.
Also take care of port velocity and apply the correct Qp to keep port air velocity under 26 m/s.

B Rgds
Blaser

[brucek]

Could you check my calculations to see if I have done this properly? Thank you very much.

Yep, if you take exactly what WinISD recommends and use 1000watts as input power into the two coils in series, and add a usual electronic rolloff filter at 10Hz with a 1st order, it looks pretty good.

The dip in SPL will theoretically be boosted by room gain, so that seems good.

The velocity only goes to ~20m/sec at full power at 12.7Hz, which is only 5.8% speed of sound. In a 10inch port, my understanding is that will not make noise.

The excursion peaks at 10Hz with full power applied. The 27 xmax is the linear max and not the Xmech. From reading, the 38mm at 10Hz seems acceptable. I don't know the Xmech of that driver. Others might.

Again, I'm no expert. I just learned by reading about subwoofer construction since I knew so little about it.

The experts can comment....






brucek

[Blaser]

brucek wrote:

(the answer for parallel would be Re=1.565ohms and BL=11.93070
brucek

Hi Brucek,

Re is OK but Bl is 12.125 Correct?

Blaser

[brucek]

Well it depends whether you let the program solve it for you.

If you do as the Help file says and enter Qes, Fs, Mms, and Re to calculate BL using the TAB key to let WinISD calculate BL, then you get these two following screens when you switch between serial and parallel.





But you can enter new parameters within your project at any time and the software won't object as it will in the initial database entry...

brucek

[Blaser]

I prefer to enter Mms and Cms by myself, this is why there has been a slight difference for Bl, which will even not be noticeable at all....

Anyway, got your point

Thank you very much!