mini-box

This is the microphone connector CAD
http://a360.co/2pMHhZM
here the Hypophonia Amplification Device
http://a360.co/2pMeu8c
Here the deal
the dimensions are: height 2.5 inches, Length 2.5 inches, and width is 1.6 inches if you include the clip.
for better dimensions detail look into the pdf for the hypophonia amplification device drawing
I base my design off of the sony x11 ultraportable bluetooth speaker

• http://www.bestbuy.com/site/sony-x11-ultraportable-bluetooth-speaker-blue/6604143.p?skuId=6604143&extStoreId=&ref=212&loc=1&ksid=34abc314-af94-45b3-82ea-6b056573dd13&ksprof_id=11&ksaffcode=pg210753&ksdevice=c&lsft=ref:212,loc:2
  for me this is as small as it gets if you want quality sound and high volume.
  The volume control is the + and - signs on the mini-box device. and the P sign is for power.

There is a switch as you request for the microphone connector CAD. this switch will turn off and on the sound.
i also include a stl file so you can 3d print it out to have a better look at it.