⚠️ This curve is tuned for one specific system in one specific room. Don't copy the final YAML expecting it to sound right on your gear. Copy the process, not the curve. The point of this doc is to show how to iterate on a target curve using listening cues and measurements as your guide.
A walk-through of building a personal target curve over roughly ten listening sessions. Each section is structured as complaint → diagnosis → fix → result, which is approximately how the iteration actually unfolded.
| Component | Detail |
|---|---|
| Mains | Triangle Borea BR09 (3-way ported floor-stander, 1 × 25 mm silk dome tweeter with horn-flare waveguide + 1 × 16 cm midrange + 3 × 16 cm woofers) |
| Sub | SVS SB-2000 (sealed, -3 dB at ~19 Hz anechoic) |
| Amp / DSP | NAD C700 v1 with Dirac Live (BluOS) |
| Crossover | 80 Hz, 18 dB/oct (NAD bass management) |
| Room | Apartment living room, untreated, ~30 m² |
| Listening | Moderate-to-loud SPL, mixed music and occasional film |
A few things to know about the BR09: Triangle voices its speakers for an energetic, forward presentation, with elevated upper-midrange emphasis — they "want" to sound forward. That matters because Dirac corrects toward whatever target curve you give it: if the target is flat in a band where the speaker is intentionally not flat, Dirac will treat that elevation as a room problem and cut it away, removing the voicing along with it.
The community default. A first-order low-shelf at +8 dB — the most common starting point for music-focused Dirac calibrations, derived from Olive/Welti's Harman International listener-preference research.
base:
type: harman
params: { shelf_level: 8 }What was good: solid bass weight, neutral mids, easy on the ears. What was wrong: deep bass (below ~30 Hz) felt missing on bass-heavy modern productions with significant sub-bass content — the lowest notes were audible but lacked physical impact. And the speakers felt "smoothed away" — less forward and articulate than they sound un-corrected.
We tackled the sub-bass shortfall first (clearer fix, less subjective), then the speaker-character problem (more nuanced).
Complaint: "I can hear the sub but the lowest notes don't have the visceral, physical-pressure quality I expect at this SPL. Sub-bass content (20–30 Hz) feels recessed."
Diagnosis: Harman-8 already plateaus at +8 dB down to 10 Hz, so the target itself isn't capping the level. The issue is the equal-loudness contours: the contours steepen sharply below ~30 Hz, so a given SPL is perceived as significantly quieter at 20 Hz than at 50 Hz. To make the sub-bass band feel proportionate at typical listening levels, the target needs extra energy in the 20–40 Hz band beyond the shelf — psychoacoustic compensation, not flat reproduction.
Fix: A wide PEQ centred at 30 Hz, +2.5 dB with Q 0.9, to lift the sub-bass band on top of the shelf.
transforms:
- peq: { freq: 30, gain_db: 2.5, q: 0.9 }Result: sub-bass became physically perceptible on tracks with deep low-frequency content. The 20–40 Hz region is now the loudest band on the target — a deliberate over-flat shape that compensates for the steepening equal-loudness contours at low frequencies. (Not true isophonic compensation, which would require an SPL-dependent target; just a bump in the right place at one assumed listening level.) The fix exposed a secondary issue.
Complaint: "Now the 100 Hz region feels boxy — voices and upright bass have a 'cardboard tube' quality."
Diagnosis: with the sub-bass PEQ added, the 80–150 Hz band ended
up at roughly +5 dB on the target. That's the classic "boxiness"
zone, and the room's modal response was likely piling up there too.
Two ways to address it: cut that band with a surgical gain
transform, or tighten the Harman shelf corner so the shelf decays
faster. Surgical band cuts leave non-natural shapes in the curve;
adjusting the shelf corner is cleaner.
Fix: move shelf_corner from the default 105 Hz down to 85 Hz —
the shelf falls off faster, cutting ~2 dB across the boxiness band.
(Spoiler: 85 turned out to be slightly too tight once the warmth
PEQ was added in Stage 5 — we relaxed it back to 95 in Stage 6.
Iterative tuning.)
base:
type: harman
params: { shelf_level: 8, shelf_corner: 85 }Lesson: when a complaint maps to a band, the first reflex shouldn't always be a surgical PEQ. If the underlying shape is wrong, fix the shape. Surgical EQs leave kinks in the curve; shape adjustments don't.
Complaint: female vocals and cymbals have audible sibilance and a harsh, glassy quality.
Diagnosis: with a flat target above 400 Hz and Dirac correcting through the top octave, the room is being driven toward a flat in-room response all the way up. In a real listening room the in-room response naturally rolls off above ~8 kHz (off-axis directivity of the speakers + absorption by soft furnishings and carpet; atmospheric absorption contributes a smaller portion). Correcting toward a flat target through that naturally-rolled-off band lifts the 5–10 kHz region — exactly where sibilance lives.
Fix attempts (this took a few tries):
- Switching to the
olive_welti_inroombase with a -1 dB/oct tilt → too dark; the entire top end was rolled off rather than just the sibilance band - A gentler -0.5 dB/oct tilt → still affected the bass (a downward tilt anchored at 1 kHz lifts everything below the anchor too, including the bass shelf)
- High-shelf cut at 4 kHz, -2 dB → cleaner, but trimmed too much of the 4–7 kHz band that gives transients their "snap"
Final: high-shelf cut at 7 kHz, -3 dB. The first-order shelf has a transition zone, so 4–6 kHz is lightly attenuated (about -0.6 to -1.0 dB) — enough to leave most of the presence/snap intact; above 7 kHz the cut deepens toward the full -3 dB, taming the sibilance band (5–9 kHz) and the lower portion of the air band (10+ kHz).
transforms:
- shelf: { type: high, corner: 7000, gain_db: -3.0 }Lesson: a high-shelf is fundamentally different from a tilt. The shelf only affects frequencies above its corner; the rest of the curve is left alone. A linear tilt affects everything around its anchor — useful for overall warming, wrong tool for surgical treble-only adjustments.
This was the breakthrough. After bass and treble were dialled in, the BR09s still felt "smoothed away" in the midrange — less forward and articulate than their natural character.
Diagnostic move: in the Dirac measurement view, switch to left and right channels overlaid (instead of the average). This separates two very different things:
- Where L and R agree = the speaker driver's intrinsic response, baked into the speaker.
- Where L and R disagree = the room. Asymmetric placement, position-dependent modes, single-side reflections.
Looking at the BR09 overlay:
| Band | L+R behaviour | Diagnosis |
|---|---|---|
| 30–80 Hz | L and R diverge by 5–10 dB | Room modes (correct) |
| 100–200 Hz | Some divergence | Mixed speaker + room |
| 200–500 Hz | L and R agree, +2 dB above target | Speaker (warmth region) |
| 800 Hz–1.5 kHz | L and R agree, +4–5 dB above target | Triangle's signature midrange forwardness |
| 2–4 kHz | L and R close, +1–2 dB above target | Speaker (presence) |
| Above 5 kHz | L and R tracking each other | Speaker rolloff + air |
The 200–2000 Hz elevation in both channels is the BR09's intentional voicing. Dirac was cutting it down to flat, removing the Triangle character entirely.
Caveat: L+R agreement isn't conclusive evidence of speaker voicing on its own. Symmetric room modes (e.g. low-frequency standing waves between parallel walls) also affect both channels. The width and smoothness of the feature matter as much as the L/R match: broad, smooth elevations across hundreds of Hz are characteristic of speaker voicing; sharp single-frequency peaks typically indicate modes.
Lesson: combine L+R overlap with shape — broad+smooth+matched ≈ speaker; narrow+spiky ≈ room. Use this to decide whether to EQ a peak away or leave it alone.
Two PEQs to lift the target back toward where the BR09 naturally plays. Dirac then cuts those measured peaks less, letting the speaker's voicing come through.
The character lift — 1 kHz, +2 dB, Q 0.6 (wide bell, roughly 1.5 octaves):
transforms:
- peq: { freq: 1000, gain_db: 2.0, q: 0.6 }This covers 400 Hz – 2.5 kHz with the peak centred at 1 kHz — matches the broad band where the BR09 naturally elevates the upper-midrange.
The warmth lift — 350 Hz, +1 dB, Q 1.0 (narrower, focused):
transforms:
- peq: { freq: 350, gain_db: 1.0, q: 1.0 }Picks up the separate ~300 Hz Triangle warmth bump that the wider 1 kHz PEQ doesn't fully reach.
Result: the BR09 character returned. Vocals more forward and present, acoustic guitars more articulate, snare attack more defined — without losing bass weight or re-introducing sibilance.
Lesson: if your speakers were chosen partly for their tonal character, don't let Dirac flatten that character away. Lift the target where the speaker naturally rises so Dirac cuts less there.
Complaint: "Adding the warmth PEQ at 350 Hz makes the curve feel disconnected — there's a gap between the bass shelf and the warmth lift."
Diagnosis: back in Stage 2 we tightened shelf_corner from
105 Hz to 85 Hz to reduce boxiness. With the new warmth PEQ adding
energy in 250–500 Hz, the over-tight shelf created a valley at
around 150–200 Hz between the bass shelf and the warmth band. The
curve fell into a hole, then climbed back out — visually weird, and
audible as a disconnect between the bass region and the warmth.
Fix: loosen shelf_corner from 85 to 95 — a compromise
between the default 105 and the over-tight 85. Lifts 100–200 Hz
by ~1 dB so the bass shelf flows continuously into the warmth band.
base:
type: harman
params: { shelf_level: 8, shelf_corner: 95 }Lesson: every parameter interacts with every other parameter. A fix that solves a problem in isolation can create one elsewhere. Always re-check the shape after adding a new transform.
name: Living room (Triangle BR09 voicing)
output:
path: living-room.targetcurve
device_name: Living Room
low_limit_hz: 10
high_limit_hz: 24000
base:
type: harman
params:
shelf_level: 8
shelf_corner: 95 # Stage 2 + 6: tightened from 105 → 85, then relaxed → 95
transforms:
# Stage 1: sub-bass immersion bump (equal-loudness compensation)
- peq: { freq: 30, gain_db: 2.5, q: 0.9 }
# Stage 5: Triangle warmth region (~300 Hz)
- peq: { freq: 350, gain_db: 1.0, q: 1.0 }
# Stage 5: Triangle character lift — preserve the speaker's natural
# upper-midrange forwardness rather than flattening it
- peq: { freq: 1000, gain_db: 2.0, q: 0.6 }
# Stage 3: high-shelf cut to tame sibilance and air-band harshness
- shelf: { type: high, corner: 7000, gain_db: -3.0 }
breakpoints:
resolution: third_octave
freq_range: [10, 20000]
Stage 0 has the plateau at +8 dB; the Stage 2 snapshot adds the +2.5 dB lift at 30 Hz (Stage 1) and tightens the bass shelf for boxiness (Stage 2); the final adds the Triangle warmth and character lifts (Stage 5) and the air-band high-shelf cut (Stage 3). Each step is small; the cumulative effect is decisive.
- Read the L+R overlay sooner. I spent several iterations guessing at "is this voicing or is this the room?" before switching to the per-channel view. That single diagnostic is much faster than iterating blind.
- Use a high-shelf, not a tilt, for treble-only adjustments. I initially reached for a downward tilt to tame HF harshness, thinking it was a "treble-only" tool. It isn't: a downward tilt anchored at 1 kHz also lifts everything below 1 kHz, which re-bloated the bass. A high-shelf only affects above its corner, so the rest of the curve stays untouched.
- Adjust shelves before reaching for PEQs. When the warmth
band felt off, the first reflex was to add another PEQ.
Adjusting
shelf_cornerby 10 Hz was the cleaner move and didn't introduce a new transform.
For your system, the process — not the curve — is the gift:
- Start with a known-good baseline (Harman-8 is fine).
- Listen on real music with sub-bass content. Identify the
biggest single complaint and frame it as a frequency band:
- "Lacks impact" → 20–40 Hz
- "Boxy" → 80–250 Hz
- "Hollow" / "thin" → 200–500 Hz
- "Sibilant" → 5–9 kHz
- "Dull" → 10+ kHz
- "Vocals smoothed away" → 200–2000 Hz
- Use the L+R overlay in Dirac before adjusting anything. If a peak appears in both channels at the same frequency, it's most likely speaker voicing — don't EQ it away.
- Prefer shape adjustments over surgical EQ when possible. Adjust the base curve's shelf or tilt parameters first; only reach for a PEQ when a surgical bump is truly needed.
- Reload, listen, repeat. Each
curveforge buildtakes a few seconds; you can iterate dozens of times in an evening. - Keep the recipe in version control. Diffing two YAML versions tells you exactly what changed between two listening states.
The final YAML at the top of this doc will probably sound wrong on your system if your speakers aren't Triangle BR09s, your sub isn't an SB-2000, your room isn't a similar size and untreated, or your listening level isn't moderate-to-loud. The shape changes were targeted at a specific speaker's voicing and a specific room's modes. Use the methodology to find your own.