DSP allows the user to “shape” the signal according to the needs of their system.
There are 3 things that impact the sound going to your ears:
- your content
- your hardware
- your listening environment (headphones, room, etc…)
All 3 can often be improved, and sometimes improving it using DSP is easier (or even possible) than improving the original item.
Think about the Audeze DSP presets. The Audeze LCD-4’s aren’t “broken”. They don’t need to be “fixed”. There are compensations that can be done in DSP which improve them because DSP is a different domain than physical headphone design. You can do things in DSP would be cost prohibitive in hardware design.
Nothing wrong with adding a bit more bass to your music than the crossover designer allowed for in your speakers
Got reflective flat walls? Room correction via convolution filters can help.
Changing the phase of your audio, or the mapping of your outputs sound to match your hardware can correct errors otherwise very difficult to resolve. I have one room with a speaker that is about a meter further from the listening sweet spot than the other speaker… easy to fix in DSP, hard to change my wall or my wife’s design for the layout of the room.
On and on… there is a ton of you can do with DSP.