This is a rather clever idea.
The TonewoodAmp is a device that allows acoustic players to add the type of sounds, usually only available by plugging in to a chain of FX pedals and then an amp.
It attaches to the back of your acoustic guitar, and seems to require a soundhole pickup, but instead of then sending that signal out to an amp to hear it, it sends it to a transducer on your acoustic. This turns your guitars body into a speaker for the effected signal. The result is a blend of your guitars natural acoustic sound, along with whatever effect you have dialed in on the Tonewoodamp, and both sounds are coming from the guitar itself. It can also be used along with Midi apps for more possibilities!
This explanation from Tonewoodamps is probably clearer.
How does it work?
In general the body of an acoustic guitar is used to amplify the sound the strings produce. When the strings are plucked, they begin to vibrate the bridge of the guitar (1). As a result of the bridge vibrations, the top (front) plate also begins to vibrate (2). For the lower frequencies, the vibrations are transmitted to the back of the guitar, then bounce back through the sound hole (3).
ToneWoodAmp adds an additional layer of vibrations using a driver that is attached to the back of the guitar (4). These sound waves are pure sound effects such as reverb, delay, echo, tremolo, etc. and even virtual MIDI instruments (using iDevice). The combined results of the effects plus the natural strings’ sound create a unique playing experience which is heard directly from the sound hole and felt through the body of the guitar itself (5).
It attaches by gluing two magnetic ‘rails’ to your guitar with a glue they say won’t damage the guitar, and is easily removed. The Tonewoodamp then attaches to these magnets. There is also another “locking system” for attachment that is still in development. They are currently taking pre-orders at the introductory price of $90, which they say is half price. There is no mention of a ship date.
Here’s a link to their site : tonewoodamp.com
Here’s some demos:
