[buke9]

Sorry let me restate. On my QP1R there is no change in volume if the eq is set to flat with it on or off. The volume is the same . Did I say something different?

 

[buke9]

I would assume it's pretty much this. My guess is that they just lower the master gain, hence when you use the flat preset, the frequency adjustments doesn't occur but the master gain is still applied.

Your assumptions are based on what? Where did you get that the master gain was lowered -10 db on all master gain for all presets ?

 

[castleofargh]

Manny DAPs lower the volume when eq is engaged they do this to prevent the amp section clipping . IE if you were already at a high volume close to the amps capacity then boosted the base the amp would be pushed beyond its limits

this.


the basic principle is that is you have a 0dB signal(loudest sound recorded on a track) and you digitally boost it with EQ or another DSP, you clip it. and that's not cool ^_^. different devices have different approaches to that issue:
-some just don't care. if you clip you clip.
-some apparently don't care but they in fact always have an attenuated gain by default, that way no need to bother about when to change things or not, and no issues about intersample clipping or whatever. usually they find a middle ground between protection and losing too many bits(which in turn will show as worst SNR on digital stuff). so such protections don't mean it's impossible to clip the signal when pushing everything to the max of when stacking up several processing options(I can clip my sony DAPs pretty easily if I add up DSPs).
-some lower the gain the second you turn the EQ ON, even if it's with everything flat. because who cares about that one time some dude want to use the EQ with no setting? it's just practical and simple to lower the gain when EQ goes ON no matter the setting.
-some advanced stuff might have an auto gain linked to how much boost you use or to checking the signal itself to prevent clipping(although I'm not sure DAPs would bother with that sort of options).


in conclusion for OP, it's nothing and it doesn't matter. first time I remember reading about this gain going down even without an EQ boost on a DAP was for the old sansa clip, so it was a while ago. it's just one choice so the user will be less likely to ruin his sound by using his EQ poorly. "it's not a bug it's a feature".

 

[Dulalala]

Your assumptions are based on what? Where did you get that the master gain was lowered -10 db on all master gain for all presets ?

Firstly, I did specify -10dB is an example, not an absolute value. Secondly, its because it's generally what is done. Why its done to flat, I have no clue, probably lazy programming. Here's a post from Fiio to prove my point.

Q: Why does the volume decrease when EQ is enabled?

A: The equalizer is implemented in the digital processing stage, and includes a filter stage and a digital gain stage. Volume is controlled after digital-analog conversion. The equalizer filter can effect a maximum increase of 6dB in a frequency band; if this is done without lowering the digital gain, it could cause the digital signal to clip at 0dBFS and cause audible distortion. Lowering the analog volume afterwards has no effect on the distortion. Thus to preserve signal integrity, a digital gain of -6dB is added when equalizer settings are enabled to avoid clipping. This does not affect audio quality except in so far as you need to turn up the volume afterwards.

http://fiio.me/forum.php?mod=viewthread&tid=39939

 

[TYATYA]

Some eq reduction of overal gain with purpose advoiding sound clipping. It is software programmer choice to use or not to use.
It didnt show but may be a fix value like -3dB for gain. Since it start active when eq on (not depending on value eq, even zero), flat eq will have lower out put.