Designing a box for a car with WinISD

[SINTORMAN]

Yeah i did just enter the ones he listed in the order he listed them. It just makes me annoyed that I can't get all the specs to line up .... I guess I will just take it even though they are slightly off.

[Fallen]

Originally Posted by SINTORMAN

Yeah i did just enter the ones he listed in the order he listed them. It just makes me annoyed that I can't get all the specs to line up .... I guess I will just take it even though they are slightly off.

It is irritating, but since they are dependent on each other it happens. Meanwhile some of the parameters are measured with different methods. So there can be a bit of error. The main thing is that the ones that need to agree do in WinISD. Otherwise you can't save the driver and that's just a pain in the ass.

But anyways if you're noticing a huge difference in BL(Magnetic Field X Length of Wire in the gap) it's sometimes because the manufacture lists it with the coils in series, and lists the Re of a single coil. In which case make sure you go back and enter the Re of the 2 coils in series(ie double the value).

If things are out just a bit don't worry about them too much.

[SINTORMAN]

Originally Posted by Fallen

It is irritating, but since they are dependent on each other it happens. Meanwhile some of the parameters are measured with different methods. So there can be a bit of error. The main thing is that the ones that need to agree do in WinISD. Otherwise you can't save the driver and that's just a pain in the ass.

But anyways if you're noticing a huge difference in BL(Magnetic Field X Length of Wire in the gap) it's sometimes because the manufacture lists it with the coils in series, and lists the Re of a single coil. In which case make sure you go back and enter the Re of the 2 coils in series(ie double the value).

If things are out just a bit don't worry about them too much.

Well the BL is off by .06,,, the QTS is off by .002,,, the FS listed is 26hz but WINISD has it as 26.76,,, the CMS is off by .1,,, the SPL is off by .36.. I don't think its going to make a huge difference but What do I know lol.

[Fallen]

Originally Posted by SINTORMAN

Well the BL is off by .06,,, the QTS is off by .002,,, the FS listed is 26hz but WINISD has it as 26.76,,, the CMS is off by .1,,, the SPL is off by .36.. I don't think its going to make a huge difference but What do I know lol.

Yeah that's pretty typical.
Cheers!

To top it off the T/S from sub to sub in the same production run can vary quite a bit. IIRC CMS can vary 40% between subs in the same batch. The main thing is it gives you an idea of how the subs will perform. If you're ever super bored you can try varying the parameters and plotting the modified subs against the original(keeping the box the same obviously). Keep in mind you can't easily hear a difference of less than 1dB.

[Subbin Blazer]

Great tutorial, i'll have to give this a try. It's my first time using Win ISD, so let's see how it goes...
Can someone direct me to the specific Win ISD program that I need? I noticed that there is an "Alpha" version, but not sure if that's the one I need, it did mention something about bugs so i don't know which to go with...
I'm on Windows 7 32 bit home premium if it matters. Thanks

[49konvict]

I have the alpha and the only glitch it gives me is you can't close it by the x button. You have to shut your computer down to close it other than that it works beautifully

[jmelton86]

Originally Posted by 49konvict

I have the alpha and the only glitch it gives me is you can't close it by the x button. You have to shut your computer down to close it other than that it works beautifully

Mine did that, too. Windows 7 64bit.
There is a new version out now, version 7 or something, that works perfectly.

The graph is white instead of the old black graph.

[cxa0897]

i find alpha to be a lot better. alpha lets you model the transfer function, xmax, and port velocity, which you cant do in the regular winisd. just use task manager to exit out of it and you should be good to go

[Subbin Blazer]

Ok, thanks guys. I download the Alpha version.
Let's see when i can have some time to mess with this.

[Subbin Blazer]

Ok, thanks guys. I downloaded the Alpha version, let's see when I have time to mess with it.

[Electrodynamic]

Originally Posted by Fallen

It's normal for some of the parameters to differ from the manufacturers. Especially if they exaggerate certain ones. Try to stick to the ones I suggested entering, they tend to work best in my experience. (plus they are more or less the most commonly published ones as well)

Originally Posted by Fallen

It is irritating, but since they are dependent on each other it happens. Meanwhile some of the parameters are measured with different methods. So there can be a bit of error. The main thing is that the ones that need to agree do in WinISD. Otherwise you can't save the driver and that's just a pain in the ass.

But anyways if you're noticing a huge difference in BL(Magnetic Field X Length of Wire in the gap) it's sometimes because the manufacture lists it with the coils in series, and lists the Re of a single coil. In which case make sure you go back and enter the Re of the 2 coils in series(ie double the value).

If things are out just a bit don't worry about them too much.

Originally Posted by Fallen

Yeah that's pretty typical.
Cheers!

To top it off the T/S from sub to sub in the same production run can vary quite a bit. IIRC CMS can vary 40% between subs in the same batch. The main thing is it gives you an idea of how the subs will perform. If you're ever super bored you can try varying the parameters and plotting the modified subs against the original(keeping the box the same obviously). Keep in mind you can't easily hear a difference of less than 1dB.

I do agree that some manufacturers have issues like that. However, we are not the latter and we do not do the things you have mentioned. For instance the Cms can be easily reverse calculated to 0.07 mm/N where as Klippel gathered T/S's list Cms as 0.08 mm/N which is considerably less than the 40% change that you eluded to previously. Our Qts was measured by Klippel at 0.61 and we list it at 0.55 (right at 10% deviation) and BL measured by Klippel at 18.1 vs. the 20 that we publish (right at 10% deviation) which is well within production tolerances.

[zonaplay1]

thank´s for take the time for explain the winisd process, is very important to me learn more about winisd.

[sivertsdad]

it gave me problems as well good to know im not the only one havnt been brave enough to try the original one.

[sivertsdad]

it gave me problems as well good to know im not the only one havnt been brave enough to try the original one.

[DamienNicholas]

Can anybody try to plot the audioque HDC3.0 15" dual 1 ohm subwoofer with win-isd? I cant seem to do it, also the 8" 2.0 series. I need to build a center consol for 2 of the 8's and im having issues with the port and box size for the 15's. The box is pretty big: 9cubes after port and subs disp.

[Slobalt7]

Is this where you got the .707 for f0 and fp?

The peak at tuning has nothing to do with the port size. It has to do with the system Q.
The box size, tuning frequency, and driver t/s parameters determine the peak vs. frequency response.
Here is a quote from Dan Wiggins (pretty sharp guy when it comes to subwoofer for those of you that don't know):
Qtc > 0.707 will have a bump in the response, loses some accuracy (tightness) and bass extension. The higher the Qtc (0.8, 1.0, 1.3, etc) the less accurate and the less deep bass you get.
Qtc=0.707 is called the Butterworth alignment. It provides the most bass extension you can get without the bump. Good all-around compromise alignment.
0.707 > Qtc > 0.577 is considered overdamped. Better accuracy, a bit less bass extension as compared to the Qtc=0.707 alignment.
Qtc = 0.577 is considered best transient accuracy. It's also known as the Bessel alignment. This alignment has the flattest group delay, which means that signals in the passband go through the speaker at the same speed, so everything stays coherent.
0.577 > Qtc > 0.5 are considered heavily damped. They offer some additional benefits, such as less overshoot and ringing, which can be desireable in higher order systems.
Qtc=0.5 is critically damped. This is the point where you finally reach zero overshoot in the signal. You will have no ringing. Considered "transient perfect", because there is no overshoot, IMHO it's not a significant gain over the Qtc=0.577 situation.
Qtc < 0.5 is considered overdamped. You're not ringing, but you're taking longer to reach the final state of the system. Things get slow down here.
GENERAL NOTES:
The lower the Q, the shallower the "knee" in the response. The slower the transition from flat to rolling off.
The lower the Q, the tighter the sound (to a point).
The higher the Q, the more midbass output, and the higher the peak SPL.
The higher the Q, the boomier the response, and the less accurate the response.
IN GENERAL: responses around 0.7 are considered "ideal" for car use. They are typically considered audiophile grade, with very good accuracy and extension. Higher Qtc values are considered more SPL oriented, lower Qtc values are considered more musically/SQ oriented.
Qtc variances of 5-10% are basically inaudible; you'll be hard-pressed to hear the difference between a Qtc=0.66 box and Qtc = 0.74 box.
Hope this helps!
Dan Wiggins
Adire Audio

[cxa0897]

I don't know if fallen will chime in or not, so I'll try to answer for him. Basically, qtc is a measure in a system's frequency response curve. a qtc of .707, the butterworth alignment, is a smooth roll off and is commonly used in a broad range of applications, one of which is our audio systems.

here is a quick visual to give you an idea of how it affects the response



also keep in mind, this is an approximation, just another reason to pick a response that is sort of "middle ground" as opposed to something towards one end

[Fallen]

Originally Posted by Slobalt7

Is this where you got the .707 for f0 and fp?

the .7 for fp and f0 is to give the linkwitz transform a smooth transition when simulating cabin gain. Doing it this way gives you the typical 12db/oct gain.

So in this case it actually has nothing to do with the tuning of the sub. It's just to create a filter that simulates cabin gain. You'll see .707 show up a lot, it's a magical number