Staggered stud walls are an effective way to prevent sound from getting out of your home theater, AKA 'Man Cave'. In a regular stud wall, sound waves hit one side of the drywall, travel through the stud and into the drywall on the other side. Since the stud connects the two sheets of drywall, the sound has a solid path to travel through. The trick is to separate both sides of the wall. That way, the sound won't be able to cross the wall as easily.
There are a couple of ways of doing this. One method would be to build two separate walls. Another would be to build one wall but with 2x6, 2x8, 2x10, or even 2x12 top and bottom plates, depending on your thickness requirements for the wall.
For this tutorial I'll be demonstrating building a single wall in SoftPlan with two rows of 2x4 studs and 2x8 plates. I'll also show you how to stagger the studs so they don't touch each other for your 3D framing details.
The first step is to build a custom wall. Start out by going to File-->Drawing Options-->Drawing Options-->Define Wall-->Edit. Or you could simply edit an existing wall and select 'Definition' down at the bottom left of the Wall Edit dialog.
Select an existing wall such as the 2x4 interior wall and then select Save As. Give it a new name like 8" Sound Wall and then click OK. Make sure your new wall is selected then start editing it to match how the wall will be actually built.
Change the top and bottom plates to be 7 1/4". Give the interior drywall a Horizontal Start of 7 3/4". The Horizontal Start determines how far into the wall a material begins. Since we have 1/2" of drywall then 7 1/4" of plate the interior drywall would begin at 7 3/4".
Next we need to add another row of studs. Select Add Material. An Adobe Brick material will be added to the inside of the wall. Edit the Adobe Brick and change the material to Stud. Give it a Width of 3 1/2", a Height that matches the previously existing stud, a Horizontal Start of 4.25", and a Vertical Start of 1 1/2". This places the new stud along the inside edge of the 7 1/4" plates.
If you use a texture to shade your studs on the screen make sure to move the slider way over to the right and place a check for the Texture. If you print your studs with a solid fill also make sure that the pen settings for the new stud match the existing stud.
Now if you look at the Plan view Wall Definition graphic you will have what appears to be two walls side by side. If you prefer to display the wall as one thick wall you can add an additional material following the method described above. Then change this material to 'None', give it a width of 1/4" and a Horizontal Start of 4". This will fill in the gap between the studs. Then uncheck the Inside Visible for the original stud, uncheck Outside Visible for the new stud, and uncheck both Inside Visible and Outside Visible for the 'None' material. Use the same Texture and Pen settings for the None material that you used for the Studs.
If you want to show insulation in the wall you can add insulation as well by adding an Insulation material. If this is an interior wall you don't want to change the Stud to Stud Insulated. Doing so would make this an Exterior Wall. Exterior walls have different properties than Interior Walls such as the way trim is applied around openings.
Your new double stud wall is now complete so select OK to exit out of the Wall Edit dialog.
After you insert your new double stud wall you may notice that the ends don't join up cleanly at Tees and Corners. So what I do is to edit the wall and change the Wall Join Tolerances to 0" and adjust the wall to butt into the other walls rather than joining up with them.
If you look at the framing in Framing Mode and 3D you will see that even though we do have double studs they are not staggered. So the next step is to go to Framing Mode and move the studs on one side of the wall. Select Move Block and draw a box around all the studs in one side of the wall. Move the studs 8" one way or the other to make them staggered from the other side of the wall. You may need to add an additional stud to make the framing work out right. While still in Framing Mode select Add Stud and add in any studs necessary to fill in after moving the studs as well as for tees and corners.
Bill is the owner and maintainer of SoftPlanTuts.com