Sex or Music EDIT 1 (now ORGAN SYMPHONY WITH ORCHESTRA)

[Magpie]

Hi Kolemath, an enjoyable poem with a metaphor that works. I have a couple of issues regarding technicalities and terminology, nothing too serious though. Also I agree with Leanne regarding the title, with a poem like this it is quite important to have a title that doesn't give it all away.

 
Sex or Music
 
If you are a violin, -- I also think that you could drop the repetition of 'if', without it the statements would seem more definite.
I am a bow.
 
If you are a trumpet,
I am a valve.
 
If you are a trombone,
I am a slide.  -- This is the first of my technical issues - A valve is part of a trumpet and a slide is part of a trombone so for me these two statements don't work in the way that the other two do. A bow is a separate implement that makes the violin sound and likewise the mallet to the xylophone. I was thinking about what the equivalent would be for trumpet and trombone and I suppose it would be breath or air which doesn't work for what you are wanting to say. 
 
If you are a xylophone,
I am a mallet.
 
I tune you, listening
for the perfect pitch in key -- musically this line doesn't seem to make much sense. Pitch is only paired with 'perfect' as a descriptor when talking about people with 'perfect pitch' who are able to identify the pitch of a note without any reference note. And 'key' is used for a piece of music. This stanza could be written as
I tune you, listening
to your pitch
to test and taste the sound
to test and taste the sound.

 
The curtain is pulled,
conductor and orchestra together.
The first score light,
slow and gentle, delicate,
easing into the fullness of a bouncing bridge, more -- Another technical issue with 'bridge' - I'm not sure how many people are aware that it is a musical term for a passage in a piece of music. I only say this because before I became a musician when I heard James Brown say "Take it to the bridge" I presumed he was talking about a big metal thing stretching over some water, which was quite worrying.
tempo and crescendo, climax of movements,
orchestra, conductor, one sound in swells,
fingers clenching
neck and bow,
horn and note,
mallet and key,
brass over strings,
the percussion crashing,
perfect pitch, harmony, -- careful with 'perfect pitch' again here. I do like how you have constructed this stanza with the line lengths and the fact that it is all one long sentence. 
 
all finishing together,
and the conductor collapses,
and the orchestra gasps for air
and all in the hall,
 
renewed.
 

I like the poem and most the comments that I have left are of a technical issue regarding music, so nothing too serious but still issues that should be addressed.

Thanks for the read,

Mark