A target curve tells Dirac Live what you want your system to sound like. Dirac measures what your speakers and room actually do, then designs filters to move that measured response towards the curve. Change the curve and you change the tonal balance: more or less bass, brighter or softer treble.
Target curves in plain English
Beginner
Why not just use a flat line?
Flat sounds logical, but in a normal room most people find it thin. Dirac says most preferred curves lift the bass by about 4 to 8 dB compared with the midrange, and roll the treble off gently, by about 2 to 6 dB at 20 kHz. That’s why almost every popular curve slopes down from left to right.
What the graph shows
- Left to right is frequency, from deep bass (20 Hz) to the top of the treble (20 kHz).
- Up and down is level. Above 0 dB means more of that frequency, below means less.
- The line is only a target. How close Dirac gets depends on your speakers and room.
Three rules that save most problems
- Use the same curve on every speaker, including the subwoofers. Different curves in the bass make the combined result miss the target.
- Don’t ask a speaker for bass it can’t play. Boosting below what a speaker can reproduce wastes power and can damage it.
- Treat any curve as a starting point. It’s a preference, so try a couple and keep the one you enjoy.
Next: see the popular curves compared, or go straight to the downloads.
This follows Dirac’s own target curve guide and widely used Dirac Live guidance.
Where the popular curves come from
Advanced
The Harman research
Many curves trace back to listening tests by Sean Olive, Todd Welti and Elisabeth McMullin at Harman (AES, 2013). Their preferred in-room response had a bass lift of about 6.6 dB below 105 Hz and a treble cut of about 2.4 dB above 2.5 kHz. Dirac notes the research assumed a controlled room, calibrated speakers, a seated listener and moderate volume.
The Harman curve files widely shared for Dirac Live are flat above 400 Hz, so they don’t include that treble cut. If you want it, add it yourself with a control point or a shelf.
Limiting how far Dirac corrects
You don’t have to correct the full range. Dragging the right-hand curtain in stops Dirac correcting above that point, so the speakers’ own treble is left untouched. Some experienced users correct only the bass and lower midrange, where the room causes the biggest problems.
Bass Control and ART change the rules slightly
With Bass Control, the lowest part of the curve is shared by the whole system. With ART, each group has its own curve, and a subwoofer in its own group has no curve of its own. See Bass Control setup and ART setup.