Hey,
I found onions and oily food generally ruins my voice, so i avoid that before gigs. I gaveup ice a long time ago, becuase i always lost control over my voice after having ice.
The best thing ive found for a soothing throat is 1 tsp. honey + blackpepper. and orange juice with blackpeppe. also, for range improvement, ive realised few drops of concentrated eucalyptus oil in a cup of green tea 30 minutes before i start singing does wonders.
overall, i find for better vocal performance and range development, practice practice and mroe practice is inevitable.
just my $0.02
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~Jay
Yamaha PSR-3000
Korg i3
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~DJay
PSRS910