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Author Topic: Blue "bit perfect" light and Volume changes  (Read 2937 times)

blgentry

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Blue "bit perfect" light and Volume changes
« on: January 25, 2016, 08:40:57 pm »

I was just discussing this on another forum and someone said that if the blue light is on, then the signal going to the DAC is "bit perfect".  But this clearly is not true because when you change volume using Volume Leveling, Adaptive Volume (peak level normalize), or Internal Volume, the bits going to the DAC are *definitely* being altered in order to change their volume.  Unless I'm missing something?

So why does the light stay blue when changes are clearly being made to the stream?

Brian.
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ferday

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Re: Blue "bit perfect" light and Volume changes
« Reply #1 on: January 25, 2016, 10:17:39 pm »

you are correct

however i was under the impression that the blue light was just for "no processing" and not an actual "bit perfect" light.  i could be wrong



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RD James

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Re: Blue "bit perfect" light and Volume changes
« Reply #2 on: January 26, 2016, 01:01:44 am »

I think this only applies if you're playing a file that is less than your output bit-depth.
So you should still get the blue light up to -48dB if you play a 16-bit file with a 24-bit output.
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Arindelle

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Re: Blue "bit perfect" light and Volume changes
« Reply #3 on: January 26, 2016, 04:36:18 am »

I think this only applies if you're playing a file that is less than your output bit-depth.
So you should still get the blue light up to -48dB if you play a 16-bit file with a 24-bit output.
But as James says thats a lot of headroom before anything is really "lost" (attenuated?, not sure of the proper terminology?)

As the signal is being processed at 64bit, rounding it out it works out to basically 6db per bit. So  a 16bit file will give you -48db to play around with, a 24 bit file 40db which is still very big.

This is oversimplifying so if any recording engineers want to chime in for more detail (or correction) ... or a nice laymen's link explaining headroom

Changed my skin to check and the blue light doesn't turn off though.
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blgentry

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Re: Blue "bit perfect" light and Volume changes
« Reply #4 on: January 26, 2016, 09:38:19 am »

Irrespective of output bit depth, changes ARE being made to the audio data being sent to the DAC when volume changes are in effect.  So the blue light isn't exactly "accurate" in this respect.  It's not a big deal; I'm just asking why that choice was made and verifying that "yes indeed audio changes are being made for volume adjustments".

Brian.
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ferday

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Re: Blue "bit perfect" light and Volume changes
« Reply #5 on: January 26, 2016, 09:48:16 am »

i never thought about it until you posted...as someone who uses room corrections and/or EQ in every situation, i've never seen the blue light come on :)
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RD James

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Re: Blue "bit perfect" light and Volume changes
« Reply #6 on: January 26, 2016, 11:45:20 pm »

Changed my skin to check and the blue light doesn't turn off though.
Is this a bug? I thought they added that calculation when they decided that volume control would not always disable the blue light.
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Arindelle

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Re: Blue "bit perfect" light and Volume changes
« Reply #7 on: January 27, 2016, 04:10:08 am »

Is this a bug? I thought they added that calculation when they decided that volume control would not always disable the blue light.
Didn't know they did that so not sure if its bug or not. Just checked again -48db and below the blue light still is on with 16bit Flac playing.
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