DRC User Guide
From DRC
Contents |
DRC Userguide
DRC is a complicated piece of software. In effect what we want to do is play a known signal through our hifi system and (using a fairly decent microphone) record what we actually get at the primary listening position
By now comparing what was sent with what was received we can figure out what distortions are occuring to our signal. It is then possible to derive a filter which reverses some of the distortion effects.
DRC takes what is effectively the error term in the signal and calculates this correction filter. However, its not trivial to measure this error, nor is it trivial to find the right params for DRC. The discussion below aims to help the user understand what is going on and how to manage each step.
You should definitely also take a look at the excellent walk through written by Jones Rush. Although it is written from the point of view of a windows user, it offers a step by step guide to do everything from measuring the impulse response of your room through to operating DRC to generate the filter. Get the most recent version from here:
http://www.mooneyass.com/DRC/ (Seems to be offline, copy archived here: DRC_Guide_v1.0.pdf )
Step 1 - Setting Up Your HiFi System
Measure everything! Getting the speakers eactly equidistant from you, and also the same distance from rear walls makes a HUGE difference in sound quality (much more than some new cables).
Then start to think about rear and sidewall echos. These muddy the sound and blur the soundstage. Sound busters are hard to get past the wife, but I have some evidence that a large leafy plant placed in the right spot can have a similar effect... (strange but true...)
Clean your connectors. If you have speaker wire running directly to the binding posts, then consider chopping off the exposed chunk of wire and stripping back another inch and using that. Removing oxidation on cables makes a big difference to the bass.
Step 2 - Measuring the Room Impulse Response
- Generate a log linear sweep using xxxx
- Play this file through your sound system using your favourite sound player
- Record the sound using your favourite sound recorder
- Generate the impulse by convolving the recorded sound with the original sweep file using xxxxx
So what is an Impulse Response anyway? Click here for more info
Also see this link for a really detailed example of how to read an impulse response and measure your room: Impulse response analysis
Step 3 - Using DRC to Calculate a Correction Filter
You need to create a drc config file based on one of the standard templates
See here for some design ideas for a GUI to generate the config file
DRC takes the impulse response that we generated above, plus any microphone calibration files, and your DRC configuration file and generates a filter that can be used to correct your system.
Step 4 - Playing Your Music Through the Filter
Use Brutefir, Foobar2000 or something else to take the correction filter and apply it to your audio files.
