I guess almost every guitarist has got his very own place in the rehearsal room. Next to him his amplifier. For a long time you have been adjusting the setting of your amp to get the sound you have longed for and so you will be pretty irritated if the other band members do not like your tuning. Or you will be surprised that in another location your amplifier does not sound as good as in the rehearsal room.
One thing you should keep in mind is that the sound of the speaker of your amplifier varies depending on the position of the listener – this is a simple law of physics. While treble is projected straight forward and therefore maybe sounds unpleasant to a listener right in front of the speaker, the bass is distributed quite indirectly.
And especially to open back combos the reflection matters. All those emissions and reflections influence the sound of your guitar.
Furthermore the sound of open back combos varies with every inch of distance between the amp and a wall. The sound waves that are produced by the speaker need another period of time to arrive the ear of the listener than those sound waves that are reflected by the wall. This causes a phase cancellation which influences the sound.
Because of this it is possible that you will recognize the treble more intensive while you play your guitar on stage, in front of your amplifier.
For this problem Weber created a useful little helper. Bolted in front of the speaker, the 10“ Beam Blocker will distribute the frequencies more smooth. Even if you walk back and forth in front of the speaker the sound will stay more equable.
But not everybody likes the variation of the sound that can be produced by using a beam blocker.
Deeflexx developed beveled elements that can be set in front of the amplifier. They also should scatter the sound more even.
This sound diffusers made of a high-tech synthetic substance is able to split the beam by its interlocked wedge shape. The signal appears less shrill and the sound will be like in the sweet spot of the amp even if you are next to or behind the amplifier.
Famous users of the Deeflexx are Marcus Deml, Rabea Massaad, James Burton (formerly Elvis Presley), Jon Herington (Steeley Dan) and Michel Kosho Koschorrek (Söhne Mannheim).
Joe Bonamassa uses the Clearsonic Sound Shields to produce his sound at his live gigs. By doing so he is able to play his amplifier pretty loud without drowning the Band.
I think trying to simulate the position of the walls of your rehearsal room might makes sense. Therefore you can place your amp in front a case or a self-made element (always in the same angle). But unfortunately these elements would have to be several meters high and wide to create a similar effect.
And also the ground plays an important role. Everyone that has ever placed his amp on a wooden ground knows what I mean. The ground transmits the bass that we can feel in our feet. This aspect can be important to the feeling of playing. And while you are playing on a stone ground you might get the feeling that something is wrong with the sound.
The manufacturer Eich Amplification developed elements for bass-players that can be connected to the amp which transmits the signal to a board on the ground on which the bass-player stands.
In an interview with Keith Richards I have read that he always puts his amplifier on the ground when he is recording at studio.
Of course there are also musicians that does not want this effect and place their amplifier on a tripod to undock it from the ground.