Help with understanding Melco music HD app and other UPnP

[Thomas Chiles]

Dear Audiophile Style Community,

 

I have a Melco N1 music server that is directly connected to a Berkeley Alpha USB that in turn, is connected to a Berkeley Alpha DAC 2. My music files are stored directly on the Melco hard drive(s). The Berkeley DAC 2 is fed directly to a MC275 valve power amplifier. There is no preamp. between the DAC and the power amplifier.  I control/adjust volume using the Berkeley Alpha DAC 2 preamp stage (using a remote).  I manage my music library and control playback by way of an iPad using a Melco music HD app, which is very similar too and actually identical to a Mconnect HD player that I have used in the past.  

 

I noticed recently that both the Melco and Mconnect players have an adjustable volume control embedded in the software application. I had no need to take notice of this as when the app loads the volume is automatically set to the highest (max) level.   This feature does control play volume through my system.    I am writing as I am confused as to why these software apps have an adjustable volume control?  I understand that if you are listening to music on the iPad itself one needs this feature to adjust volume, but with the Berkeley DAC2 is being rendered by the Melco app software, what purpose does this feature serve? 

 

More importantly, does the volume setting controlled by the app impact sound quality in any negative way?  The DAC 2 reads a correct sampling frequency regardless of the volume adjustment on the app.   At present, I set the volume to the max level and adjust playback volume via the Berkeley DAC 2 preamp remote volume control. My confusion stems, in part, because I do not understand fully how player software interfaces with the music server beyond managing the stored music library.  

 

Explanations by the AS community will be greatly appreciated,

Best,

Tom

 

 

[PAR]

The volume control on the Melco app is there so that users may adjust volume for the system without the need to get up from their listening position.  Not every system configuration has other volume controls available.

 

Volume controls on an app work by discarding bits. So in order to avoid audible loss of resolution the app needs to have both adequate headroom in respect of the amplifier matching the sensitivity of the speakers and the bit depth needs to be adequate to cope with the losses without audible repercussions. So a volume control based upon  32 bit resolution is less likely  to cause audible loss than a 16 bit one.

 

I am finding this hard to explain so, briefly, the best solution is to set the app volume to max ( i.e. 0dBfs) which means that there is  no attenuation by the app and to use the pre-amp to control volume. If the pre-amp has no remote then you lose the advantage of controlling volume from your listening position but gain full resolution of the source. NB: That is theory , in reality I cannot hear any loss of resolution in my system as the volume is lowered and, therefore, bit depth is reduced via an app or other digital volume control as the sound  becomes too quiet to notice  such factors😉.

[PAR]

On 8/16/2019 at 10:15 PM, Thomas Chiles said:

I understand that if you are listening to music on the iPad itself one needs this feature to adjust volume,

 I'll just add for clarification that the volume change does not happen within the app itself. The app is only a control interface and is telling the Melco N1 to reduce/increase  the signal it sends to your Berkeley device.