🔧 INSTALLER LEVEL: Professional Crossover Configuration

Active vs Passive Crossovers

Passive Crossover:

Illustration in preparation Description: Schematic of passive crossover with capacitors and inductors, showing component speakers connected

Components: - Capacitors (block lows, pass highs) - Inductors (block highs, pass lows) - Resistors (level adjustment)

Location: Between amplifier and speakers

Pros: - No power required - Simple - Reliable - Included with component speakers

Cons: - Power loss in components (heat) - Fixed frequencies (can't adjust) - Component tolerances (±10-20%) - Interacts with speaker impedance

Active Crossover:

Location: Before amplifier

Types: 1. Built into head unit (basic) 2. Built into amplifier (common) 3. Dedicated DSP (professional)

Pros: - Adjustable frequencies - Adjustable slopes - No power loss - Precise filtering - Time alignment possible (DSP)

Cons: - Requires separate amp channels - More complex - More expensive - Requires tuning

Which to use?

Passive: - Simple systems - Component speakers with included crossovers - Budget builds

Active: - Serious systems - Custom installations - Competition - Maximum performance

Crossover Point Selection Methodology

Step-by-step process:

Step 1: Identify speaker capabilities

Check specifications: - Tweeter: Fs = 1,200 Hz → Cross >2,000 Hz - Midbass: Fs = 80 Hz, Usable to 3,000 Hz

Step 2: Determine overlap region

Where both speakers can play: - Tweeter: 2,000 Hz and up - Midbass: 80-3,000 Hz - Overlap: 2,000-3,000 Hz

Step 3: Choose crossover point in overlap

Considerations: - Lower (2 kHz): - Tweeter plays more range (more output, more distortion risk) - Midrange has less work (better power handling)

• Higher (3 kHz):
  • Tweeter protected (less distortion)
  • Midrange works harder (possible distortion)

Typical choice: 2,500-3,000 Hz

Step 4: Select slope

For this overlap: - 12 dB/octave: Good starting point - 24 dB/octave: Better if speakers widely separated

Step 5: Listen and adjust

• Too much treble: Raise crossover or lower tweeter level
• Too little treble: Lower crossover or raise tweeter level
• Harsh sound: Steeper slope or raise crossover
• Smooth but weak: Gentler slope or lower crossover

Subwoofer Integration

Subwoofer crossover is critical!

Frequency selection:

Low crossover (50-63 Hz): - Subwoofer only for deep bass - Front speakers carry more bass - Use when: Large front speakers (6.5"+ midbass)

Medium crossover (80 Hz): - Most common choice - THX standard - Good for most systems

High crossover (100-120 Hz): - Subwoofer does all bass work - Protects small front speakers - Use when: Small front speakers, factory integration

Slope selection:

12 dB/octave: - Gentle integration - More overlap with front speakers - Can cause boom if not careful

24 dB/octave: - Clean separation - Most common - Good all-around choice

36 dB/octave: - Very steep - Maximum separation - Good for sound quality - May sound disconnected if not tuned well

Subsonic filter:

Essential for ported enclosures!

Illustration in preparation Description: Diagram showing subsonic filter protecting subwoofer below tuning frequency with excursion graph

Function: - Extreme high-pass filter - Protects subwoofer from over-excursion - Filters infrasonic frequencies (below hearing)

Settings: - Sealed: 20-25 Hz - Ported: 5-10 Hz below tuning frequency

Example: - Box tuned to 32 Hz - Subsonic at 22-25 Hz - Slope: 24 dB/octave minimum

Phase Alignment

Phase = Timing relationship between speakers

In phase: Speakers move together (reinforce) Out of phase: Speakers oppose (cancel)

Illustration in preparation Description: Waveform diagrams showing in-phase vs out-of-phase signals and resulting sum

Phase switch on amplifier: - 0° = Normal - 180° = Inverted

When to invert:

Test by listening: 1. Play bass-heavy music 2. Toggle phase switch 3. More bass: Correct setting 4. Less bass: Wrong setting

Physical explanation:

If subwoofer and front speakers move opposite directions: - At crossover frequency they cancel - Weak midbass response - Inverting phase fixes this

More advanced: DSP can adjust phase continuously (not just 0° or 180°)