I have an extra noisy neighbor. So I researched ways to muffled the noise. And created peace for myself.
This project is about making an acrylic window add on to existing window frame without modifying the house window or frame. I only add four nails to the window frame.
The cool part is using earth magnets to seal the windows to the frame.
Double pane windows are costly in comparison and require modification to the house.
These sound proofing windows decrease the noise substantialy and are easily removed with one's hands.

Step 1: Acrylic Sheet Cut and Prep

I bought a 48"x 98" 1/4 inch thick sheet at Tap Plastics and had them rough cut it in four equal pieces of 24.5" x 48".
I rested each sheet on the inside ledge in front of each window. I measured 40 mm from the edge in side the frame to the edge of the acrylic sheet. This gave me space for the magnet to be inserted on the acrylic sheet. Then I marked the excess width of the acrylic sheet.

I cut the excess sheet off with my circular saw and a plastic cutting wheel (modified triple chip wheel).

After all four sheets were cut to fit. I spot-faced the backside in four locations with a Forstner bit. to a depth of 0.11, the thickness of the magnet to be glued in the hole. The cuts are not all the way through the sheet!

Step 2: Locate Nails Based on Magnets in Sheets

I applied superglue to the four spot-faced holes and layed in each magnet. The magnets are 0.11 thick and 0.7 diameter rare earth magnets. They should lay in flush to surface of acrylic.

The nails need to be hammered in the frame behind the magnets in the sheet. One nail per magnet.

Step 3: Shields Up and Noise Down

It's a not perfect block for sound. But it is effective in reducing the sound and not interfering with my enjoying the sun through the window.

Materials:

48" x 98", 1/4" thick Acrylic sheet
4 each/window Rare earth magnets
Super glue
Larger head nails, roofing nails work best

Tools:
Circular saw
Plastic cutting blade
Forstner drill bit
Hammer