Some people like to hear music precisely as it was recorded, which is why the most expensive audio equipment purports to do absolutely nothing to affect the original audio signal. Others like to tweak their sound. Whether you're on a Mac or PC, there's a way to set a global equalizer across everything—iTunes, browsers, Spotify, Rdio, Pandora, iHeartRadio, or whatever else you listen to.
Even your system sounds will be affected. If you're a sound-tweaker, this is important information, because it means you no longer have to hunt around for the equalizer that is missing from most of those apps anyway. The instructions vary based on whether you are on a Mac or a PC. Let's start with the PC.
On a Windows PC
Unfortunately, every Windows PC is a little different, and whether you have a built-in equalizer depends on your audio drivers. Here's what it looks like on my system, but if you don't see it, see if your sound card offers separate drivers or another audio tool that has an equalizer built-in. Many do, you just need to check your manufacturer's web site.
1. Open Sound ControlsGo to Start > Control Panel > Sounds. That looks like this on Windows 7:
2. Doubleclick the Active Sound DeviceYou have some music playing, right? If not, start some, using whatever application you want. Once it's playing, you'll see little green bars light up next to the thing that is playing your music. Double-click that.
3. Click EnhancementsNow you're in the control panel for output you use for music. Click the Enhancements tab to bring up a bunch of options:
4. Check the Equalizer boxLike so:
5. Choose a PresetWith some soundcards, you can access a graphic equalizer like the ones your Mac friends use. On my fairly standard HP box, you can only choose presets. To find out how they sound right as you select them, check "Immediate mode," and then start trying the presets:
If I were you, I'd try that "Custom" setting too; on my box, nothing happens, but I have seen evidence that it works on other Windows machines. Either way, you have now set an EQ setting globally, across your entire PC, once you hit the OK button.
On a Mac
The keys to this bit of musical magic are entirely free software: Soundflower from Cycling74, makers of the amazing Max/MSP software, which lets smart people build neat stuff (including an NES danceclub visualizer, a heartbeat-driven "Call Me Maybe" controller, a city-remixing taxicab, and invisible dubstep instruments); and AU Lab, from Apple itself.
Here's how to use Soundflower and AU Lab to control sound equalization globally:
1. Install SoundflowerThis part is easy—just grab the most recent .dmg file for your system. Click it after it downloads to install it, just as you would any other Mac software from the web.
2. Install AU LabNow, you'll need Apple's AU Lab software (.zip file).
3. Restart Your MacYou know the drill.
4. Turn Your Volume All The Way UpBefore you monkey around with the rest of this stuff, turn up the volume all the way with headphones plugged in. Then do it again without headphones plugged in. Once you complete this process, the volume will get controlled at the next part in the chain, so if you start out too quiet, you won't be able to get back to top volume.
5. Make Your Mac Output to SoundflowerThe beauty of Soundflower is that your Mac thinks it's an audio output, which, in a sense, it is. To set up your Mac to route all sounds to Soundflower, go to System Preferences > Sound, and choose the two-channel Soundflower option:
6. Make AU Lab Input from SoundflowerGo to Applications > Utilities, and double-click AU Lab to open the program. Now, you just need to set the input to Soundflower, like so, and then click Create Document:
7. Add EqualizationNow you can see under the hood of AU Lab, which can add a wide array of effects to your sound. Unless you want to experiment with the rest of them, proceed directly to AUGraphicEQ, and select it as an Effect in Audio 1.
8. Tweak ItAU Lab defaults to giving you 31 bands of equalization, which allows for fine tuning—probably too fine, for most purposes.
You'll probably want to switch to the 10-Band equalizer instead using that dropdown button to the lower left. Here's what that looks like with the bass frequency sliders dragged up for more low-end:
Sometimes this can make the sound a bit distorted, so instead of raising the bass, you could alternatively lower everything else instead, and turn up your volume. When you're done, you can save it as a preset like this:
Now, every sound your computermakes will be EQ-ed just how you like it. And if you followed Step 4, you'll still be able to use your volume keys to reach your Mac's top and bottom volume levels. (If you skipped that, you can go back and change it after the fact.)
Evolver.fm editor Eliot Van Buskirk has covered and occasionally anticipated music and technology intersections for CNET, MP3.com, McGraw-Hill, Wired, The Echo Nest and other outlets full-time since 1997. He regularly appears on NPR, and his Evolver.fm articles are currently syndicated to Gizmodo, Wired, Time, Billboard, Hypebot, Huffington Post, Drowned In Sound, MTV O Awards blog, MidemBlog, and other outlets. He plays music and rides a bicycle just about anywhere.