Q: I’ve been reading a lot of manufacturer specification sheets lately, and I have a (perhaps silly) question.
Why is +4dB considered to be the professional standard? Is it because it outputs a hotter signal, or does +4 also give you better signal-to-noise ratio and frequency response?
A: First of all, thank you for reading the specification sheets. Good for you, and thanks for asking the question!
+4 dBu, being a higher level is slightly more robust — although frequency response and other specs are not inherently improved just by raising the level.
Minor improvement (not really related to the level) comes more from the fact that because it is slightly more expensive to implement, +4 tends to appear on higher end equipment, with better specifications.
But even more importantly, +4 dBu equipment is usually balanced, which gives benefits in noise rejection and cable length issues.
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