[Mike Gillespie]

What are the sound quality advantages of getting music off a local drive rather than streaming it off a network drive NAS via hardwire in your house?  I can go both ways and am not sure what's better.  Coming off either a Mac Mini or a PC.  To the local drive, I can go firewire, Esata, or USB.  Thanks.

[firedog]

The big advantage of a external local drive is that it takes up less space and usually means less cabling.

The advantages of a complete external server PC/MAC/Linux box:

• • Network protocols can deliver your audio to a network capable DAC w/no jitter. This may or may not have relevance, depending on your setup.
  • External server can be built to be fanless, silent, and virtually noiseless, so it is both externally quiet and produces little interference that can negatively affect sound quality. NAS boxes and external HD boxes tend to have noisy fans and are built as general purpose machines (not dedicated for audio only) and usually are both physically and electronically noisy. They also have limited computing power and may not be able to run all audio related programs you are interested in. Some have no real server functions and are just external drives.
  • External server of high quality and low noise can be built for low cost with careful selection of components.
  • There is a school of thought that says best sound is obtained from computer system that is audio only and not general purpose - hardware and software and OS optimized for audio. OS on one drive and playback library from another drive.

[firedog]

sorry mistake

[Vincent Kars]

Although Firedog thought his answer a mistake, I do think it is useful.
It demonstrates that there are many options and as many opinions about this subject.

I’m afraid a lot of these solutions and reported improvements are system specific and the testing procedures are often not documented.

However as we talk computers there are a lot of things you can try for free.

Does playback from a HD has a negative impact on the SQ on your system?
Download a player  like JRiver or Foobar and configure memory playback.
Does it make a differences for you compared with playing straight from the HD?

Take another computer and store a couple of songs on it.
Play from the local HD and using file sharing over the network using the songs on the other PC.

If you have 2 Win7 PCs, try media sharing. This is DLNA, a true streaming protocol.
You can compare
-   Playing from the local HD
-   Playing the audio local using the library of the other
-   Etc

If you don’t hear a difference, stop bothering and choose what is most convenient to you.
Success

[Noseyears]

If you don’t hear a difference, stop bothering and choose what is most convenient to you.
Success

True that.
In case of a fire a NAS is more convenient though..you could unplug and run out with your NAS box 

[srb]

In case of a fire a NAS is more convenient though..you could unplug and run out with your NAS box 

A "local" hard drive could be an internal drive, but might also be an external drive in its own enclosure connected by eSATA, USB, FireWire, Thunderbolt, etc. - which can also be conveniently carried away.
 
Steve
 

[sfraser]

it "should not" make a difference, bit's are bits, however there are a lot of variables involved. I will assume your music player is a PC/MAC? With either local or remote music storage the bits should  be the same as they hit the input stage of your DAC/sound card of your player. Some may argue that  local hard drive may add some ambient noise. Other may argue remote Ethernet storage may cause jitter drop outs etc. I have tried both, and both work equally well, But I do prefer keeping all my digital content in a common server in my basement.