Audio EQ Settings

Since I went to the dark side, and started using gentle parametric EQ to correct the FR of headphones & speakers to neutral, I want to collect the EQ settings here. My general philosophy is to make subtle corrections. FR response deviations are often related to other forms of distortion like phase or ringing. Amplitude corrections big enough to restore completely flat response can exacerbate those other factors. Thus I stick to subtle, gentle corrections that improve neutrality yet preserve the original character of the sound, short of restoring perfectly flat response.

When boosting levels, remember to apply a reduction in overall gain to avoid clipping. Take the biggest amplitude boost at any frequency and cut by that amount. This is in the voltage (not power) domain, so dB = 20 * log(V1/V2).

For example, if you apply +2.5 dB @ 4.5 kHz, then you must reduce overall gain by 2.5 dB, which is a gain ratio of 1 / (10^(2.5/20)) = 74.98%. Or just use 74%. When it comes to gain ratio, to avoid clipping, lower is safer. So always round down (truncate the decimal), not up.

Sennheiser HD-580

Characteristic FR: flat down to 50Hz, then roll off bass at about 6 dB per octave. Gentle dip of about 5 dB between 3500 and 9000 Hz. Narrower dip of about 6 dB between 10 and 17 kHz.

Parametric EQ Correction:

  • +4 dB @ 25 Hz, Q=0.67 (2 octaves wide — 1 each side)
  • +4 dB @ 14 kHz, Q=1.3 (slightly under 1 octave wide)
  • Gain: -4 dB = 0.63 = 63%

Subjective Difference:

This simple EQ transforms the venerable HD-580 making it more open, natural and neutral. Deep bass extension without impacting mid-bass and linearity. Slightly crisper transients and “air”. Even though the midrange is untouched, it sounds a touch more open, less boxy.

Audeze LCD-2

Characteristic FR: flat from zero to about 2 kHz. Gentle dip of about 7 dB between 2k and 9k. Flat from 9k on up.

Parametric EQ Correction:

  • +2.5 dB @ 4500 Hz, Q=0.67 (2 octaves wide — 1 on each side)
  • Gain: -2.5 dB = 0.74 = 74%

Subjective Difference:

Normally the LCD-2 sounds perfectly natural, yet a touch soft like listening from the 5th instead of 1st row, and correspondingly soft on detail. This EQ brings the LCD-2 back to the 2nd row and restores some lost detail, but without affecting its near-perfect voicing. It transforms the LCD-2 into the perfect headphone!

The 2016 and later LCD-2 are a touch brighter and need less EQ. Say 2 dB for these, and 3 dB for the 2014 model. CSD plots show the LCD series headphone tends to ring or resonate around 4-5 kHz, which is the trough of their natural response curve, so you don’t want to boost this freq too much.

Magnepan 3.6/R

Characteristic FR: depends on the room. My listening room has floor-to-ceiling tube traps 2′ diameter in corners behind the listener and 4″ thick RPG acoustic foam on the wall behind the listener. This EQ is busier than the headphones, which is unavoidable with in-room speakers, though I still managed to keep the rates gentle.

Parametric EQ Correction:

  • +3 @ 32, Q=0.67 (2 octaves wide — 1 on each side)
  • -2 @ 90, Q=1.41 (1 octave wide)
  • +3 @ 240, Q=0.4 (1.5 octaves wide)
  • -2.5 @ 1000, Q=0.67 (2 octaves wide)
  • +3 @ 3000, Q=1.41 (1 octave wide)
  • Gain: -3 dB = 0.7 = 70%

Of these, the bold-faced ones correct anomalies inherent to this speaker. The rest are room corrections. That is, the Magnepan 3.6/R is a near-perfect speaker when set up properly in a good room, but it rolls off the low bass and has a gentle lift around 1 kHz. The other 3 settings are corrections to my room.