zolko60 Posted July 12, 2019 Share Posted July 12, 2019 I have almost sorted out what is going on with Helix input and output levels by my and my friends research. The professional standard for line level audio signals is +4dBu. If we assume 15dB headroom to full scale digital level (0dBFS) is the standard Line 6 has adopted then Helix has three level settings: Line level: +19dBu full scale (+4dBu reference with 15dB of headroom) Instrument level: +11dBu full scale (-4dBu reference) Mic level: +8dBu (-7dBu reference) The pad on instrument input labeled "Guitar In" is 5dB so padded input is +16dBu full scale. Hx FL/RA "Aux In" is just another line level input. The Volume Kob is a digital attenuator assigned before chosen DA converter(s). Now let's see what is happening when we interface Helix with Yamaha MG06 mixer by XLR cable: Let's input -4dBu sinus signal to Guitar Input. It will appear at Hx XLR outputs set to mic level as -7dBu. MG06 mic preamp gain range is 20-64dB. At minimal gain position we get +13dBu. Getting unity gain is not possible without engaging mixer 26dB pad. Using DI box is better because they usually attenuate an amplitude by 18-20dB (plus some padding). -4dBu input signal appears at Helix XLR or TRS outputs set to line at +4dBu. After DI box -14dBu. At min mic pre gain we are near the unity. What I don't know is if Hx FL/RA mic input is set to the same mic level standard (0dB gain=-7dBu reference with 15dB of headroom=+8dB full scale). I would appeciate if somebody could confirm that. Thank you for your attention and research cooperation. :) Yamaha MG06 manual http://shopwl.com/content/MG06 Mixing Console - Manual.pdf 1 1 1 Quote Link to comment Share on other sites More sharing options...
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