Ya but the same rule applies, you cant buy common sense, any level headed smuck would have known that was not right.
He prolly put some numbers in all focked up

 

Enter the other values in that equation, play around with it!! I didn't say it works 100% first time everytime, I played around with it, I often ran into that problem, but honestly when you figure it out the first few times, it gets easy quickly!!

 

No SPLzd are easier you just enter the #s into the formula and BANG!!! SPLzd are made.

 

Here's my plan of action when building boxes with WinISD Pro.

1. Determine if it's gonna be SQ or SPL. SQ will most likely be sealed. SPL will most likely be ported. Some order bandpass can be used as well but these are trickier to make.

2. Input the TS params of the sub into WinISD Pro, if they aren't already in there.

3. Start a new project in WinISD Pro for your sub. WinISD Pro will suggest either a sealed or vented box based on your sub's TS specs. Cross check this against item 1 above. If WinISD Pro says vented, do vented. If WinISD Pro says sealed, do sealed. If WinISD is somewhere in the middle, go with either but watch your xmax plot later on. If your box pref is the opposite of WinISD Pro's box type suggestion, pick another sub.

4. The program will then give you an optimal box. Watch the transfer function graph while changing the size of the box and/or port lenght, type, size if this is a vented enclosure. I like a graph that starts flat and stays flat until the response rolls off at 20-30 Hz. I like SQ. You may want more punch and decide to resize the box to give a peak at 60 Hz or so... but be careful, the car's interior will add to the response shown on this graph. This graph is effectively not considering the car. Usually, the low lows end up being a bit louder, in car... but this is where the art comes in and maybe an EQ.

5. You'll now have the size of the box and port length required. Add on the displacement of the driver(s), figure out and add on the displacement of any bracing you'll use, and add on the displacement of the port, if used. Then you'll have your inside volume requirement.

6. Do an extra check in WinISD Pro. Set the wattage you plan to input into the driver(s) and then check the linear excursion chart. If it indicates that you'll be exceeding xmax of the driver, figure out if you can resolve this issue with eq or a subsonic filter, or if the box size, ports, etc... need to be adjusted.

7. Run WinISD (not Pro) and do the whole thing again. Enter the TS specs into this program, create a project for a box with same size, type, ports etc as in WinISD Pro ... then add the additional volume you calculated in step 5 to the box volume - the chart will be off but you're just going to use WInISD for box panel calulations. So continue to use the box size calc to give you the sizes of the panels.

This is about where I took my packing noodles to the fiberglass garage and built my own custom formed box based on the volume. No MDF, aside from the 3/4" ring that the driver mounts to, was used. I used a carboard box to define my noodle volume, filled the cardboard box with packing noodles to the volume mark and then used the measured noodles to check/adjust the size of the fiberglass enclosure along the way. You could use sand or water, but the noodles in a garbage bag make it really easy to measure.

Alternatively, now take your great total volume number and plop it into any online or other box panel calc software to get your panel sizes. And yes, no less than 3/4" MDF for a MDF-based box, eh.

 

Or, hey, just read the WinISD Pro documentation. This installed when you installed WinISD Pro. Read the Getting Started section.