The way we perform is related to the physical space we play in and the mental space we play in.
First, let us consider the physical space. I played in a hall that was rather dry when I was in the Nashville Symphony. In a recent post in Adaptistration we learn from acoustical consultant Christopher Blair that
Prior to moving to moving to the new Schermerhorn Symphony Center, the Nashville Symphony performed in the multi-purpose Tennessee Performing Arts Center. The farther the musicians were seated behind the proscenium of that facility, the more forceful they had to play to make an impact in the room.
Particularly affected were brass and percussion sections. As they played louder, other musicians became concerned about their hearing. These sections were pushed further back (the seating area for the orchestra became very large), and a forest of plexi-glas shields appeared.
In moving to their new home, in which all the musicians play within the audience chamber, the players had to learn a new way of listening and responding to the lively new acoustics. The brass, in particular, quickly learned to temper their efforts, and despite the much smaller seating area provided to the orchestra (better for ensemble) the plexi-glas shields have largely disappeared.
My main memory was that the old hall was very dry even with the electronic reverb on and the brass did not project very well in the audience. I did not perceive my playing style to shift louder due to the hall (although it might have), but I do recall that my articulations were intentionally somewhat long. I was just aiming to match the group but the reason we did that at all was because we had to effectively create a bit of reverb to help out the dry space. I am sure they must be enjoying the new hall; I would love to someday play in it.
In my teaching I try hard to hit the middle of the road on this issue and also try hard to help students be able to control the extremes from very short to very legato so they can adjust to any acoustic.
The other performing acoustic is your mental place that you play. David Vining in his recent publication What Every Trombonist Needs to Know About the Body gives a good example. We can easily get used to only performing in a practice room sized space, and that may become the only space we mentally feel ready to play in.
Some trombonists are shocked every time they walk out onto a concert stage because it is so much bigger than their practice space. When we are inclusively aware, we can claim for ourselves as much space as we like. We are not confined to a small practice room nor are we required to fill an airplane hanger with our trombone sound.
When we put ourselves in a right relationship with space, we claim as much room as we need to move to play trombone and this includes room to move the slide! Some trombonists experience tension because they confine themselves to a space which is too small to accommodate their bodies and their instruments. To put yourself in a right relationship with space is to understand your trombone playing needs and to allow yourself to occupy all of that space, whether you are in the practice room or on the concert stage.
This book is an excellent book that I would highly recommend reading; most topics translate to horn easily.