When mixing music, often one listen’s to the music at a loud volume and over time this can cause your mix to be a bit off. It is a good idea to listen to your mix at different volume’s go from low to high and back and forth. The idea is to get a more realistic sound. You may also want to try listening to your mix on different monitors to get more of the listeners sound. After you have done this and have your mix how you want it, move it back to your main mixing process and complete. Try to mix your music at different volumes, I think you will be more consistent.
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The Tesseract: Recording Tip 32: Keep an eye on playback levels. Listening at varying volumes.