Foobar2000 is a free, public domain program. It can be downloaded at : http://www.foobar2000.org .

It runs only on PC hardware, not Apple Macs. But there is also a recent mobile version supporting all three phone platforms -- IOS, Android, Windows Phone.

On first installing it, it's interface looks very simple, but it is very customizable and there are many plug-ins available for it.

You can totally customize how Foobar2000 looks. Search online for 'foobar2000 skins' . You will find many thousands of user created skins (themes).

It supports playing a myriad of audio formats as well as can stream content from Internet radio.

It can manage very large music libraries and has powerful library search options and options to automatically monitor your music folders for additions and deletions.

It supports outputting to whatever audio drivers you have installed on your PC so you can easily switch, for example, from an external USB DAC to Bluetooth headphones.

There is even a free programming SDK for it, which has resulted in the Foobar2000 community creating many more custom plug-ins.

I run Foobar2000 as a music server on small form factor PCs.

I feel my music sounds better when played thru Foobar2000, especially when using either the bit-exact Kernel or WASAPI sound output plug-ins. But I know that's a subjective, personal thing, so I won't get into that...

If you don't already use it, you can download and install it for free and decide if it suites your needs.

My preference is to use local hard drive storage for all my music files, versus a NAS (network attached drive). So my music files reside locally with Foobar2000 on my server PCs, and I'm not dependent on the state of some other network device.

Again this is just my preference, and not necessarily a recommendation since I know there are advantages to using a centralized NAS for your music library.

If I don't have large enough internal drives and did not want to update them (i.e. if I had to also reload the OS), I also use large external USB drives to store my music.

When I update internal drives to larger drives I recycle the old ones as external USB drives using USB SATA hard drive enclosures such as the Sabrent Ultra Slim one. About $8 on Amazon.

If I had a super large music library many terabytes in size, I would re-look at using a central NAS, shared by all my different music servers and tuned to make sure there were no network performance issues.

I do have on my home network two older smaller 1TB dual drive NASs in a mirrored raid configuration, but I don't use them for my music library, though they could serve that purpose.

Again I prefer having my music files local either on an internal drive or attached USB drive.

One reason is I sometimes notice Foobar2000 can hesitate a moment when I press play on a track if there is any system delay in accessing that media file. This is more so if I'm accessing Internet radio, where Foobar2000 has to fetch media off some Internet address.

But it can also happen with an attached external hard drive if the PC has shut it down to save power if it hasn't been accessed in awhile. You can mitigate this by configuring your Power Savings modes in Windows to not turn off hard disks or suspend attached USB devices if you are plugged in.

Also with NAS drives, ideally for performance, you want wired connections, especially if you are dealing with large uncompressed audio files. But for ease of access reasons, I run some of my Foobar2000 servers attached wirelessly to my network. So I did not want to deal with any wireless network variables in slowing access to my music files from my Foobar2000 servers.

The other advantage is that having separate local disk music libraries effectively gives my several backups. But that entails a little more work when I add new files to my music library. But at this point, I'm not adding huge numbers of tracks to my library...

I still buy CDs, so I can play the original CD in one of my CD players. But when I buy a new CD, I usually rip it first thing and add it to my digital music library, so I can play it from my foobar2000 PC based systems, or small portable players with headphones.

I do also sometimes purchase HiDef music from sites like Naim where I just get a digital download and no physical media. But I still prefer also having physical media.

Also having bought many CDs from Amazon over the years, they also provide a free digital copy of eligible CDs under their 'auto-rip' program, placing them in your personal library for you to access via the cloud for playback on your PC or devices like your Kindle.

Because of the sound quality and flexibility of literally having access to thousands of tracks at my fingertips on my Foobar2000 systems, most of the time that's what I'll select for playback versus using my CD players or turntables.

But I still keep CD players in case a friend comes over and brings a CD they want to play.

CD players can sound very good. I have a Sony CD player that was tube modified by Decware and also a Njoe Tjoeb digital/tube CD player. But I have found music played off my PC based systems can sound so good and is so much more convenient. I never organized my CDs and was always trying to find certain CDs.

And if you look at the cost of a very good CD player versus putting together a PC based system, which can additionally do Internet radio or drive bluetooth headphones, interface to your phone for easy search and access, to me it made more sense to do go that route in the end.

The external DAC is the part of the computer based system that can be expensive, but you can start smaller while you experiment and can always swap out just the DAC.

Also PCs over the years have increased in performance but decreased in size, such that some will now fit in the palm of your hand.  I think when you say 'computer audio' some people visualize some big, noisy tower computer next to their amp versus one of the newer palm sized fanless computers now available.

Encoding formats... WAVs,  FLACs...

My music library consists of uncompressed WAV files, which I rip from my original audio CDs using Exact Audio Copy (EAC). EAC is a free public domain program and basically provides a bit for bit copy of audio files off CDs.

WAV files can be like a factor of 10x larger than MP3 files but fortunately today's hard drives are large and relatively inexpensive.

I chose WAV format because it is uncompressed (for good sound fidelity), but also because most devices out there will play that format.

Also that's the closest thing bit for bit of what is on the CD and I can also always convert tracks to some other lossy format like MP3 if I need to.

I found what can take a lot of time is ripping your CD collection -- and its something I did not want to constantly be re-doing if I say wanted to just to go to a higher bit rate of encoding on an MP3.

The negative of using WAV format is it does not support embedded metadata tags, so my audio files names tend to get long because using EAC I write the file with the artist, album, track number, track title contained in the file name itself.

But if I were starting out today, another very good option is to use uncompressed FLAC which does support metadata tags. Nowadays lots of devices also support that format (though Apple does not support it, but does support WAV).

But like I said originally, I really do not want to re-rip my many thousands of tracks or hassle with converting files.

Uncompressed FLAC is basically a WAV file wrappered with the metadata tags.  There is also compressed FLAC, which is also a lossless format -- think of it as a 'zip' file of an uncompressed audio file.

But Foobar2000 or your music player then has to on the fly uncompress the FLAC file, loading your PC CPU more versus processing uncompressed FLAC or WAVs.  

There was a time hard drive space was limited and costly, giving rise to various compressed file formats, but today with drive space so inexpensive why even go there when you can rip your files once in an uncompressed file format and be done with it.

Small portable players and WAVs

Two small portable devices I use and very much like are the Colorfly C3 and the SanDisk Sansa Clip+ -- so if I'm on the go I can load them up with some of my WAV files and wear a nice pair of headphones. The Colorfly C3 has a primitive user interface but its the sound quality I most like about it... 

All I have to do is make selections from my WAV audio library, and then load them into a micro sd card and then insert that into one of my portable players -- I don't have to re-encode anything.  And WAV files are almost universally supported on devices.

On recording quality

Recording quality matters a lot.  Some music is recorded and mixed so badly, encoding it in a higher bitrate or nothing else downstream in the audio chain will magically save it.

To me some of the music that sounds most 'real', like being there, is very simply mic'd. As is often done in simple acoustic sets with just a singer playing a guitar.

I think part of the reason for this, is that a lot of studios will separately record different instruments in a sound booth and then later mix that all together. But all those instruments originally weren't all together in one space playing at the same time, and I think our brains can sense that.

With Bluetooth installed on my PC audio server, instead of listening thru my DAC and tube amp, I optionally can stream audio to a pair of wireless Bluetooth headphones or to a small portable Bluetooth speaker, which I can move room to room.

The PC Foobar2000 server can be in another room, while I roam about at home untethered, but connected wirelessly to the server wearing a pair of Bluetooth headphones.

I control playback using my Foobar2000 Copilot Wi-Fi app running on my Windows phone, which I carry around in my pocket.

In Foobar2000, you can route audio out to any of the audio drivers installed on your PC, whether it be to your external DAC or to any connected Bluetooth audio device.

After pairing your Bluetooth headphones or speakers to your PC, in Foobar2000 go to 'Files>Preferences>Playback>Output>Device'.  Your paired Bluetooth device should appear in the 'devices' drop down list. After you select it from the list, Foobar2000 will then send all its audio to that device.

See the figure below, where I'm selecting my connected JBL Flip 3 bluetooth speaker as my Foobar2000 audio output device. Make sure you first pair your Bluetooth device to your Windows PC, before entering the Preferences screen or the device will not appear in the Device drop down list.

I don't get the kind of enveloping audio quality that I experience when playing thru my DAC, tube amp, and bigger speakers, but it's not bad sounding at all.

But many times when I'm moving about at home with headphones on, I'm listening to some Internet talk radio show streamlining from Foobar2000, so I don't need super fidelity.

There are so many Bluetooth headphones and portables speakers available today at all sorts of price points, and some can sound really good.

If I want super fidelity from headphones, I put on a pair of my bigger, wired headphones like my Grado RS1's and connect them to one of my headphone amps. I still can use my Foobar2000 servers as an audio source. 

So for my particulars, I usually go for smaller, light weight and comfortable Bluetooth headphones, that also don't cost a lot.

Some of the Bluetooth devices I use and like are :

This is a small sampling of Bluetooth devices -- from headphones to speakers to receivers/transmitters to PC dongles. Today there are a myriad of Bluetooth devices available to you, with new devices being introduced almost daily.

Mpow Bluetooth 4.0 AptX headphones -- about $37 on Amazon.  Nice sounding and lightweight. Comfortable, not tight fitting on my head, very gentle.  Also has an embedded microphone and so can double as a phone headset.

Puro Adult Bluetooth headphones -- about $150. See the Puro site. These headphones fidelity-wise sound better than the MPOW headphone, but they also fit tighter on my head, so aren't as comfortable as the MPOW headphones.

BlueAnt Ribbon Bluetooth AptX Streamer and HeadSet -- about $22 on Amazon. Very lightweight. The earbuds it comes with actually sound pretty good, but you can also change those and plug in another pair of lightweight earbuds or headphones you may have. I clip the streamer to my shirt. The streamer part itself has a microphone so you can also use this device as a phone headset.  I especially like using this headset if I'm just listening to talk shows on Internet radio.

Sharkk Bluetooth 4.0 10 Watt Portable Speaker -- about $55 on Amazon.  Good sound, has NFC and can double as a speaker phone.

Another Bluetooth Speaker that I use and can highly recommend is the JBL Flip 3 -- about $70-$80 on Amazon. The Flip 3 doubles as a speaker phone as well. JBL has recently come out with the JBL Flip 4 at about $99.

Other options if you want to use an existing pair of powered speakers or transmit via Bluetooth to an amp and then out to speakers, is to get a Bluetooth audio receiver, such as the HomeSpot NFC-Enabled Bluetooth Audio Receiver about $18 on Amazon. You can transmit Bluetooth from your PC audio server to the Bluetooth receiver...

Another Bluetooth receiver/ transmitter I use is the Indigo BTR9 -- about $23 on Amazon.

It you don't have Bluetooth on your PC or if you have had driver issues with supporting older Bluetooth hardware when updating to Windows 8.1 or 10, you can add a newer, small Bluetooth USB dongle to your PC.  

One Bluetooth dongle I've used and can recommend is:

SoundBot SB340 Bluetooth 4.0 USB Dongle -- about $8 on Amazon. Supports all versions of Windows from XP to Windows 10.  When paired with the Mpow headphones or Sharkk speaker, I've gotten at least 30-40 feet transmission ranges, but this also depends on the particulars of your place, like how many walls you may have to transmit thru.

If you need a greater range, there are also some high gain Bluetooth transmitters, some with advertised 100 feet transmission ranges. See Amazon.