World's Largest Dynamic Driver Headphones (DIY)

The build processes.

I was attempting a speed mod on an old tape player from a boombox with a friend and at the end we were left with a pile of random parts and 2 100mm dynamic speaker drivers. 

At first before committing and spending lots of time I made a basic mock up to see what they would sound like. To my surprise they sounded extremely good and had incredible wide soundstage.

I then spend a day flattering and trimming the front grill of the boom box so I could use it to protect the driver from being touched.

After this by using some wire form an old cooker grill, furniture foam and scraps of wood I made the headband. 

The cups are attached on using nut and bolts I brought attached to small, wooden blocks, so the cups can be swivelled. By angling the foam ear cups I could get much better imaging. I used cocktail stick grill to protect the drivers from the outside and 2 sliding metal pipes of similar diameter between the cups and the headband so it can be adjusted to fit on any head size. A small piece of elastic ribbon is used to give the sliding mechanism resistance, so it stays where you leave it. 

The original headphone jack from the boombox is wired up to the drivers with telephone cable which means the headphones can be used with any 3.5 mm headphone jack.

To make the headphone wireless I used a Fiio BTR3K which supports lossless codecs, Bluetooth multipoint and Bluetooth 5.0.

Video/pictures.