Hopefully this is the right place.
For 22 years I've gone from not knowing what DACs are, or what EQ and DSPs are good for (didn't even know the term DSP existed), to experiencing the best sound quality I've ever heard through headphones, due to learning a ton this past week or so. I thought I'd share.
I made some tweaks to foobar's DSPs that are all incredible sound-quality improvers. ...For headphones, at least. (I have Denon Ah-D2000s.)
I'll type up a guide about it now! (This is copied from my journal. I wonder if it's a decent newbie guide.)
Everyone's audio system is different, so the guide may not produce a purely positive result without further tweaking. However, if the end result turns up slightly odd, it's still a way better start than nothing. 'Cuz foobar is one the best programs ever made.
It would help to have an external sound card like this one. Well, only if you're on a laptop. ...Use Turtle Beach Santa Cruz for desktops (UNLESS YOU LIKE EXTERNAL EVERYTHING). It'll also help to have half a brain when following this guide---regardless of my godly explanation skills---so that you understand what you're doing as you go along.
1. Install foobar. (There are some optional checkboxes while doing so. I remember in the last version, you HAD to check something to get all the great stuff, but not this one.)
2. Have fun learning the SEMI-intuitive interface, setting everything up how you like. (I like having everything available in view all at once---especially the visualizations!!! It exemplifies my tech-filled existence.)
3. Download this RAR of DSPs, and put the ".dll" files in foobar's "components" folder. (One of the DSPs needs to be installed, so it's a .exe)
4. Go to File -> Preferences -> Playback -> DSP Manager
5. You're going to move DSPs from the "Available DSPs" window to the "Active DSPs" window, in this exact order (!):
a.Equalizer [Here is the Configuration setting that makes mine good. Change it if necessary.]
b.Resampler (PPHS) [Might be pointless, but everyone says it's something they use, so I dunno.]
c.Convert stereo to 4 channels
d.Noise sharpening
e.4Front Headphones
f.Matrix Mixer [Normalize: Unchecked. Multiplier: 0.8]
g.Channel Mixer [Output channels: 6. Mode: Surround. "Use subwoofer": unchecked.]
h.Bauer stereophonic-to-binaural DSP
i.Advanced Limiter
Notes:
Not all settings are the ultimate truth. I may be completely unaware about some details. Like I think going to "Preferences -> Playback -> Output -> Output Data Format: 32-bit" makes the sound better (assuming your sound card supports 32-bit); it sure as hell sounds like it! And God knows what buying a headphone amp will improve, or what better surround-sound DSPs exist. Any feedback is appreciated.
I'm not sure if that Matrix Mixer helps. But at least it's one way to lower the volume legitimately, if you find that this setup really loud. Oh, by the way, IT'S GUNNA BE LOUD. Turn down your computer's Master Volume and Wave Volume way down.
Listen to multiple songs. Get to know the settings. (Unless you know right away that your audio setup doesn't like my configuration. ...I dunno.) The level of difference in some songs' production is grand.
I think hardware EQ might be the way to go, but I find foobar's EQ to be alright, and better than the limitations of the EQ of the sound card I linked at the top of this post.
Speaking of that sound card, I just turned on some Underwater effect, and it's making everything even better. (Some cases perhaps not).
SOUND KNOWS NO LIMITS.
Here's a song that really works well for me with my setup (there are many others). It's originally a lossy MP3, but I made some various volume changes, hence flac.