A brass player's sound travels out of the bell away from our ears, reflects off surfaces and returns to our ears. Sound waves are longitudinal, meaning they travel in a straight line until they reflect off of a surface. This is the sound brass players spend years listening to, and eventually it becomes their mental image of what their sound is. Variables in the size of the room, the material of the walls and the floor, the use of amplification, and number of people in the room can have a tremendous impact on our sound. What is everyone else hearing when we play, and how is it different than our mental image?
This distinction is important to explore in order to understand that what our audiences, conductors and fellow musicians are hearing can be very different that what you are hearing.
As an experiment play a few notes at a normal volume and listen to your sound. Listen for air, resonance, volume, timbre and anything else that you can identify. Now stand a few feet from a wall and point directly at the wall with your instrument angled horizontally. Play the same thing and listen to the change in sound. How is it different? Possibly brighter, especially if you're pointing at a wall made of stone or wood. Take a few minutes and point your bell around the room at various surface with various angles and get a feel for what changes.
When a mic is placed in front of our bell and we listen on headphones we're hearing a direct sound that is much brighter and punchier that what we're used to hearing. This is what conductors hear, what the musicians in front of you hear, and obviously what the mic 'hears.' It is very worth the time to think about how this applies to playing in different situations.
STUDIO PLAYING PRIMER
There is a lot to discuss about the difference of studio playing vs concert hall playing, (and by all means we can do both well if we work at it) but if you are looking to do session work or Broadway you need to learn how to incorporate what you're hearing from your headphones into the feedback loop that fuels your embouchure and decision-making about dynamics, articulation, timbre and even equipment choices.
We've trained for years to play any note in our range at any dynamic with any articulation and with a variety of sounds. Your beautiful ppp pedal Db might be perfect in chamber music, and if you're recording that then by all means, ppp yourself away! The studio legend Jerry Hey talks about playing dynamics in this fashion. To paraphrase, and begging his
forgiveness for possibly not conveying this correctly: "We [The Jerry Hey Horns] play full volume and leave the dynamics to the mixing engineer. A forte turned down sounds great, but if they have to turn up piano it still sounds piano."
Dry recordings of ourselves can sound, well.... dry. Because they are. They haven't been mixed, edited, or polished yet. No reverb and no mastering, you get the picture. It's raw. If you can learn to play with a total focus on your time, pitch, and sound you will take care of a lot of issues in the studio. All that's left to do is listen and blend with what you hear in your headphones. Keeping our expectations based on the reality of what we're putting into the microphone is the most important part of studio playing. And the same goes for any close-mic situation, including Broadway.
In the simplest terms, any time you're primarily on a microphone the microphone is your audience. It becomes part of your instrument, so hopefully it's a nice mic!
PERFORMING IN A CONCERT HALL
On the other hand, any time you are in a concert hall the room is your audience, so hopefully it's a beautiful room! The reflections, reverb and timbre become a part of your instrument and feedback loop. You could also say that the conductor, your fellow musicians and the audience themselves are your audience, but they too are hearing the combination of your sound and the room sound.
I think this is what is meant by "play for the back row." I've never interpreted this as 'play loudly,' but to play with great clarity and allow the entirety of the room help create your sound. It's chance to take your awareness away from your horn and listen to the room, listen to your fellow musician's sounds in the room. Let the reverb be a chance to correct your intonation, or a split second of consideration given to the end of the phrase you played. It's an open air version of the feedback loop we encounter in headphones.
LIVE SOUND, MONITORS & SUBWOOFERS
I spent the better part of my 20s on the road with horn sections and played every size venue there was. From empty clubs to full baseball stadiums, the sound at a live venue can vary from night to night. It was a blast! I honestly loved the power of the sound onstage. The massive bass drums, and even my sound echoing across the chairs after blasting out of the speaker stacks. It was a challenge to learn to play with restraint: I didn't need to play loud just because the concert was loud! If I could hear myself in the monitor mix, great. If not... well, I needed to learn how to hear myself without hearing myself. (Earplugs help!)
In relation to studio playing and concert hall playing, this was a huge challenge because my feedback loop had disappeared and I was playing by feel. Learning to play by feel is one of the most difficult and important skills you can develop. In order to play confidently by feel you need to be able to play your instrument well. It can save you in a situation when you need to sound great but can't hear yourself. If Michael Jordan can do it, we can too.... right?!
Consider playing by feel to be not so different than learning to play in tune. You have to practice creating solid tone on demand, recognizing your core and adjusting accordingly. Eventually your feedback loop will tell you what playing in tune feels like. Your instrument rings, and the beats in your sound disappear, and all is well. The same goes for playing by feel - keep paying attention to how things feel when they sound good and eventually you'll be able to do it on demand.