Phase, time, crossovers, level, and EQ: five controls, five separate problems, one picture at your two ears. This page shows what each one does, the order to set them, and where they collide.
"Loud is easy. Tuned is the difference you can point to."
How to use this page
Go in order, 01 to 06. Each section assumes the last one.
On the EQ (03): tap a zone for the big picture, tap one slider for that exact frequency.
On Masking (04): tap the crossover buttons and watch a tone move turn into a crossover problem.
Stuck on a real car? You skipped a step. The Quick Diagnosis grid on tab 01 tells you which one.
Explore the 6 sections, tap to dig in
The Order Is Not Optional
Each step assumes the one before it is already correct
A car is one of the worst rooms sound ever plays in, and a DSP is the only tool that can fix it. But a timing or level error creates dips and peaks that look like tone problems and aren't. Start with EQ and you tune the wrong problem forever. Foundation first, tone last.
The fixed order. Phase → Time → Crossovers → Level → EQ.
1
Foundation · Phase & Polarity
Get the speakers pulling together
Every speaker moves the same direction on a positive signal, and drivers stay in phase through each crossover. Out-of-phase speakers fight each other; nothing later can fix it.
2
Timing · Time Alignment
Make every speaker arrive together
Delay the closer speakers so everything lands at your ears at once. This locks the image and lets the sub and midbass sum instead of cancel.
3
Integration · Crossovers
Hand off cleanly between drivers
Pick which driver plays which range, by dispersion, not by ear. In a 3-way, keep the midbass-to-mid handoff below the vocal range so one driver carries the voice.
4
Level · Channel Balance
Match loudness side to side, band to band
Balance left vs right first (this centers the image), then blend midbass, mid, and tweeter so no band sticks out.
5
Correction · EQ
Fix what's left, by frequency
With the foundation right, EQ moves are small. Cut problems instead of boosting around them.
Quick Diagnosis
Hear the symptom, know the step
Center is vague, bass thin, fills in when you move your head
Step 1 · Phase / polarity
A deep dip (9 dB or more) that moves with your head is a wiring or phase error. EQ will never fix it.
Voice stuck in the near door, image smeared
Step 2 · Time alignment
The image pulls toward the closer speaker. Measure and delay; don't chase it with balance.
Bass strong, mids strong, hole in between
Step 3 · Crossover / sub phase
Drivers cancelling at the handoff. Check slopes and phase at the XO before touching EQ.
Image sits center but leans toward one side
Step 4 · Level
The image pulls toward the louder side. Match L/R per band, roughly 1 dB matters.
Muddy, thick, no punch
Step 5 · EQ, cut the masker
Cut around 200 to 315 Hz before boosting anything. See tab 04.
Harsh, fatiguing on long drives
Step 5 · EQ, small cut up top
Tweeters firing at glass spike around 4 to 6.3 kHz. A 2 to 3 dB cut usually fixes it.
Time And Level Are Two Different Jobs
Distance breaks both, so you set both
A farther speaker arrives later and quieter. Those are independent problems: delay fixes when, level fixes how loud. Neither fixes the other.
Two problems from one cause. Delay fixes the timing; level fixes the loudness.
Time Alignment
Changes WHEN sound arrives
Timing off = image pulls toward the closer speaker and smears.
Level
Changes HOW LOUD it is
Level off = image pulls toward the louder side.
The math, not magic
Sound moves about 13,512 in/sec in a warm cabin.
delay (ms) = (farthest − this speaker) ÷ 13,512 × 1000
A 20-inch difference is about 1.48 ms: nearly half a wavelength at 1 kHz, enough to smear the center. Measure, don't guess.
A lean, not a wall. The two overlap in the middle, which is why phase at the crossover matters everywhere.
A note on bass
Below roughly 80 Hz you can't tell where bass comes from. Time alignment down there isn't about placing it; it's about making the sub and midbass arrive together at the crossover so they sum instead of cancel.
Where Sound Lives On The EQ
Tap a colored zone for the big picture · tap one slider for that exact frequency
The 31 standard bands, and where each instrument lives most strongly. EQ is the last step: it corrects what time, level, and crossovers couldn't.
One honest note on harmonics
Every note is a fundamental plus harmonics stacked above it, so one band is never only one instrument, and one cut touches more than the thing you aimed at. When in doubt, nudge two or three neighboring bands together instead of yanking one.
One note is many frequencies. A 100 Hz note also rings at 200, 300, 400, 500. The "snap" you chase is often a harmonic of a lower note.
Critical · default to cutting
Find the band that's too loud and pull it down, don't raise everything else. Cutting keeps headroom and it's how masking gets fixed. Boost only for a genuine broad dip or a target curve.
Frequency Masking & The Crossover Trap
Why snappier midbass means cutting, not boosting
When two sounds sit close in frequency, the louder one hides the quieter one. A common car example: a heavy region around 200–250 Hz buries the attack around 300–400 Hz. The fix is a cut at the masker, not a boost at the snap. And remember an EQ cut is a band, not a line: cutting 215 Hz pulls down its neighbors too (width = your Q).
Cut the masker and the snap stands up on its own. Same speaker, same amp.
Critical · two rules1. For snappier midbass, cut ~215 Hz. Don't boost ~350 Hz. 2. Within about half an octave of a crossover, an EQ move changes the blend between two drivers, not the tone of one. Crossover and phase first, then EQ off the handoff.
It All Builds One 3D Picture
Correct size and position of every instrument
Every control feeds one goal: a life-sized singer centered in front of you, instruments spread wide, drums set back, real depth. A stage you can point to.
The payoff. A properly tuned system recreates the recording's stage. Real width, real depth, not just loud.
◆
Phase & Time
Solid, focused center
The foundation everything else locks onto.
◆
Crossovers
One source, not separate drivers
Clean handoffs keep the whole range coherent.
◆
Level & EQ
Accurate tone, stable image
Balanced side to side and band to band, corrected last.
◆
The Result
Size and position in 3D
Instruments at their real size, in their real place. The whole point.
Why DSP Isn't Optional Anymore
Your factory system already has one
The automaker tuned your exact car, with its exact speakers, at the factory. That tuning is the only reason stock sounds as good as it does. The moment you change speakers or add an amp, you break it, and the leftover factory corrections now fight your new gear. That's why an upgrade can measure better and sound worse.
Louder is easy
Better is the hard part
More speaker and more amp gets loud. Without re-tuning you also get the weirdness: a voice stuck in one door, boomy one-note bass, harshness that wears you out. That's not bad gear, that's an untuned system.
Tuned to you
The part only a DSP delivers
The factory picked one compromise for the average driver. A tuned DSP dials the system to your car, your music, your taste, and keeps it correct while doing it.
The Paths To A Real Result
They all lead to a tuned processor
Swap gear onlyFactory processing still in the way, fighting the new gear. Usually the worst result.✕
New head unitEscapes the factory tuning, but often impossible in modern integrated dashes.~
Add a DSPTake control after the factory system. Works in almost any vehicle.✓
DSP, properly tunedThe full method on this page. This is what beats the factory, not just matches it.★
The catch
A processor out of the box does nothing. It has to be tuned for the specific car and speakers to even match the factory, let alone beat it. That skill is what this page teaches.
Where RPM Fits In
For the shops and installers reading this
Arc Audio, Focal, Gladen, Mosconi, Musway are built to be tuned this way: clean signal paths, processors with the channels the method needs, speakers that behave once set up right. We back the gear with calculators, configurators, training, and a real phone number when you're stuck on a car.
Want to hear the method work?
Customers: ask a shop that runs these brands. Dealers and installers: get the line card, book a tuning training, or put your hands on the demo vehicle.
