An instrument is always played in a space, and every space has its own acoustics.
Spatial acoustics is the study of how sound waves are reflected off walls and received by the musician and the listener. Electronic sounds have to have an artificial reverb added to them to sound natural.
Hard walls create a long reverb time, because they reflect sound waves easily. Soft wall materials attenuate sound (particularly high frequencies).

Because a musical performance involves producing sound waves all the time, and they are reflected over and across the space, music literally does surround us.
We not only hear sounds but also sense them with our bodies. Our ribcage resonates with frequencies in the 80 to 120 Hz range, which is why we can feel a bass drum or loud bass instrument in our gut. We also sense variations in air pressure with our skin. This is why listening with headphones can be so dangerous: because we are missing the visual and bodily sensations of live music, we may try to get the same feeling by pushing up the volume too much.
Not cool. The only thing you will end up doing is damaging your hearing.

Sound can also be conducted directly into the body. Olav Skille, Petri Lehikoinen ja Otto Romanowski designed and built the VibroAcoustic chair, which contains several speakers and plays music devised by Otto Romanowski, incorporating specific low frequencies. The premise is that the various organs in the human body have specific resonance frequencies and that these organs could be massaged by producing those frequencies.
The chair found use with athletes to help them recover from performances (and indeed is still in use in the USA). One chair was at the Music Education department in Pitäjänmäki once upon a time, and the results were inspiring.

Outdoors, where there are no reflective surfaces nearby to reinforce the sound, music has to be played loud in order to be audible, and it has to be fast to avoid attenuation of tones. Many folk instruments have a rich spectrum (e.g. the krummhorn) and a loud sound (e.g. bagpipes) and are traditionally used to play fast tunes.

In an echoey indoor space such as a cathedral, the sound bounces off hard walls, restricting the tempo of the music, because the reverb tends to blur the sound. Music in churches, at least in the early days, was simple and slow. The tempo of Gregorian chant depends on the space: when the reverb creates consonances with the melody being sung, the tempo is appropriate.

In view of this, it is hardly surprising that the earliest form of counterpoint was the canon. Here, singers mimic the effect of a reverberant space. One voice becomes two, two becomes four, and so on. It seems reasonable to assume that counterpoint emerged by listening to singing in a generous acoustic and observing which tones sound good together.

For this work, a person talking in a room was recorded. Then that recording was played back into the room and recorded again, and this process was repeated multiple times, which led to the resonance of the room being amplified, gradually obscuring the speaking voice. One could describe this as 'playing the room'.

A traditional, non-electronic musical instrument can be defined as a non-linear dynamic system with feedback.

Explanations:

• non-linear = the instrument does not respond evenly to impulses (e.g. horn ‘cracks’, uneven registers)
• dynamic = the instrument’s tuning changes according to space and time (humidity, temperature, string tension, etc.)
• system = an entity made up of several elements
• feedback = the vibrations of a tone produced have a backwards effect as well (e.g. a vibrating guitar string impacts the bridge and other strings)

It is this complexity that makes traditional instruments sound 'alive'; after all, the tones they produce are slightly different every time and change subtly over the duration of each tone.