AUDIO BASICS
Volume
•Measured in decibels
•Logarithmic scale
•Applies to fan noise as well as speakers or headphones
Sample/Bit Rate (Digital Only)
•How many times audio was sampled per second
•One sample is one point of data, allocated anywhere from 16 to 32bits of data for that single point.
•traditional audio contains anywhere from 22 to 192khz (kHz = 1000 samples) per second
DAC
•Converts digital audio files into analog (electric) sound streams that can be outputted by a speaker
•Can be integrated into a device or plugged in as an external device via a USB or Thunderbolt port, or even via a sound card in a PCIe slot.
•The backbone of sound output in modern systems, a bad DAC will make everything sound bad, no matter how good the source audio file is.
Latency
•Technically also applies to video but it’s really not a big deal with monitors compared to response times so I’m focusing on audio
•The time between audio being played by the software and the audio actually being outputted by the speaker. Applies in reverse as well with regards to sound recording, doubly so when listening to the microphone output in real time
•Ideally you want this to be 0, but various factors prevent that. Software latency is a big factor but for casual use this can largely be ignored as long as audio sounds fine to the user.
DPC (Deferred Procedure Call)
This is an operation Windows uses to assign a priority to processes or drivers that run simultaneously in the same system.
TL;DR it handles driver efficiency
If processes that are involved in streaming audio are not given a high enough priority then there would be issues with the audio streaming in 'real-time'.
Problems include pops/clicks, 'glitchy audio' and device disconnections. This is a big downside for people who want to do music production or simply watching streaming video or playing games.
To analyze your DPC Latency you can use Jarrod's currently used latencymon tool:
https://www.resplendence.com/latencymon
and not some random metal music
Basic Fixes for bad Latency:
- Update Drivers to their latest version
- Other components might be interfering with your audio. Try deducing which other hardware drivers are interfering with your audio. Common suspects are Network/Wi-Fi cards, BT adapters, Card Readers, Graphics Card and other sound devices not in use
Here's a link of a much more in-depth discussion about DPC:
https://www.reddit.com/r/windows/comments/11itqe/dpc_latency_and_why_you_should_care/
Credits: Nintonito, NTHNZO