Help with transpose tools and tips

[[Member Brai…]]

Hi!

This is a double question, musical and technical.

First, the music:

I'd like to sing the song "God help the outcasts". The original recording is in B flat, and when it builds, it goes a full tone up into C.

I'm a tenor, so I can sing the first verse in woman's octave, but when I get to the chorus, I struggle with those high notes, so I chicken down to my male octave.
I feel that going down an octave in the chorus is not very musically appealing. The second part of the song, that is in C key, I think I can continue in my octave ... but it's a bit dull.

As an option, I thought I may transpose the song. But here I cannot decide if transpose it up one tone and sing it all at male octave (again I feel it like dull), or if it would be better transposing it two full tones down (G flat) and sing the entire song in the high octave. 
What do you think would be teorically more appealing?

I supose the best option is try, listen and choose ... So now, the technical problem:

Taking a backing track four semitones down is A LOT . Can you recommend me a good software tool to do this? (free if possible).

 

Thanks!

[[Member open…]]

1 hour ago, BrainDad said:

But here I cannot decide if transpose it up one tone and sing it all at male octave (again I feel it like dull), or if it would be better transposing it two full tones down (G flat) and sing the entire song in the high octave. 
What do you think would be teorically more appealing?

Both make sense. Hard to give a general recommendation. What would sound better would depend on the individual. 

1 hour ago, BrainDad said:

Taking a backing track four semitones down is A LOT . Can you recommend me a good software tool to do this? (free if possible).

I wouldn’t know any. Transposing the finished audio mix always sounds terrible. I don’t think I ever used such a background track on Smule. I always look for actual recordings in a different key. 

[[Member Brai…]]

Thanks,I tried with an online converter, https://www.conversion-tool.com/audio?lang=en

The results are not very good for two full tones . Instruments are in the not hideous range, but the choir voices are the worst.