🔧 INSTALLER LEVEL: Professional Tuning

Parametric EQ Setup

Parameters:

1. Frequency (Center): - Which frequency to adjust - Be specific (not wide corrections)

2. Gain: - How much to boost/cut - Cutting preferred over boosting - Typical: ±3 to ±6 dB

3. Q (Quality Factor): - Bandwidth of adjustment - Low Q (0.5-1.0): Wide, gentle (2 octaves) - Medium Q (2-4): Moderate (1 octave) - High Q (8-15): Narrow, surgical (1/3 octave)

Illustration in preparation Description: Graph showing effect of different Q values on same frequency/gain, illustrating bandwidth differences

When to use each Q:

Low Q (broad): - General tonal balance - Large room modes - Musical adjustments

Medium Q: - Most applications - Typical response corrections - Good starting point

High Q (narrow): - Removing specific resonances - Feedback suppression (live sound) - Surgical corrections

Measurement-Based EQ

Process:

Step 1: Measure frequency response - Use RTA or REW - Pink noise or sweeps - Microphone at listening position

Step 2: Identify problems - Major peaks (>6 dB) - Major dips (>6 dB) - Overall tonal balance

Step 3: Prioritize corrections - Cut peaks before boosting dips - Fix largest errors first - Don't chase perfection

Step 4: Apply EQ - One correction at a time - Re-measure after each - Verify improvement

Step 5: Listen - Measurement + listening together - Trust your ears - Test with various music

Example correction:

Measured: Peak at 80 Hz, +8 dB

EQ settings: - Frequency: 80 Hz - Gain: -8 dB - Q: 3.0 (start here, adjust if needed)

Result: Peak reduced to flat

Advanced Time Alignment

Multi-way systems:

Each driver needs individual delay:

Illustration in preparation Description: Side view of car showing tweeter, midrange, woofer, subwoofer with measured distances and calculated delays

Measurement procedure:

Method 1: Tape measure

1. Measure from each driver to listener's ear
2. Note distances (in inches)
3. Subtract distances from furthest driver
4. Convert to time delays

Example: - Subwoofer (trunk): 72 inches - Midbass (door): 30 inches - Tweeter (dash): 24 inches

From subwoofer (reference, no delay): - Midbass: (72-30) / 13,500 = 3.1 ms delay - Tweeter: (72-24) / 13,500 = 3.6 ms delay

Method 2: Acoustic measurement (more accurate)

1. Generate impulse or sweep
2. Measure impulse response
3. Software calculates delay automatically
4. Apply calculated delays

Software: REW, ARTA, TrueRTA

Fine-tuning by ear:

After measurement-based alignment:

1. Play music with strong center image (vocals)
2. Adjust delays in small steps (0.1-0.5 ms)

3. Listen for:

   • Centered vocals
   • Clear imaging
   • No phasiness

4. Optimal setting = most focused image

Target Curves

"Flat" isn't always best!

In-room response should NOT be flat:

Illustration in preparation Description: Multiple target curves shown: flat, B&K, Harman, house curve, with explanation of each

Why not flat?

1. Fletcher-Munson effect:

   • Ears less sensitive to bass/treble
   • Perception requires boost

2. Room/cabin acoustics:

   • Natural rolloff at high frequencies
   • Boundary gain at low frequencies

3. Personal preference:

   • Some prefer more warmth (bass)
   • Some prefer more sparkle (treble)

Common target curves:

B&K House Curve: - +6 dB at 20 Hz - Slopes to 0 dB at 500 Hz - Flat to 20 kHz

Harman Curve: - +6 dB at 20 Hz - Slopes to 0 dB at 250 Hz - -4 dB at 20 kHz

Your custom curve: - Adjust to taste - Start with standard curve - Modify based on preference - Re-test periodically