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Passive crossover loudspeakers + stereo EQ to a fully active DSP amplifier like the AC650

  • Passive speakers use analog filters and a single amp channel per speaker.
  • AC650 uses DSP to split the signal before amplification and apply processing to each driver.
  • Goal: Understand the real performance difference between these two approaches.

Let’s compare

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Passive EQ is a Broad Brush

  • EQ applied after passive crossovers cannot target individual drivers.
  • Stereo PEQ affects all drivers playing that frequency.
  • Crossover points cause overlap, making precision impossible.

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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DSP Enables Independent Driver Control

  • Active DSP crossovers allow full per-driver control over EQ, delay, and gain.
  • Each driver gets its own amplifier channel and digital filter, allowing unmatched precision.
  • Delay the tweeter by milliseconds to align with the woofer's acoustic center.
  • Apply EQ to fix breakup or resonances without affecting other drivers.
  • DSP filters do not drift with time, heat, or load.

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Fixed Phase Relationships with FIR Filters

  • FIR filters provide linear-phase crossover capability.
  • Steep slopes without phase distortion.
  • All frequency components delayed equally—no smearing.
  • Eliminates phase shift between woofer and tweeter.
  • Improves intelligibility and realism for vocals and instruments.

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Passive Designs Drift with Heat and Volume

  • Even high-end passive components suffer from thermal and impedance variation.
  • As drivers heat up, impedance rises—crossover shifts.
  • Premium inductors/caps still have tolerances and drift.
  • Sound can change during a listening session.
  • DSP is immune to driver temperature or aging.

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Less Power Loss, Lower Distortion

  • Active systems eliminate passive losses and reduce intermodulation distortion.
    • Intermodulation distortion happens when two signals mix in a nonlinear system—like when the amplifier handles both low bass and delicate treble at the same time.
  • Passive parts waste power as heat.
  • DSP amps connect directly to drivers—no energy lost.
  • Each amp handles only one band, reducing IMD.
  • Bass content won’t modulate tweeter output.

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Total Control = Better Tuning and Adaptability

  • DSP gives infinite flexibility to match drivers and tune any environment.
  • EQ, delay, and gain per driver and per room.
  • Tweak settings in software—no soldering.
  • Match mismatched drivers easily.
  • Fast, measurable, reversible improvements.

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Section

Premium Part

Qty

Unit $

Weight

Line Loss

Woofer LP (24 dB)

10 mH 18 AWG Air‑Core

2

$34.51

300 g

0.45 Ω

​

47 µF Superior Z‑Cap (x7)

7

$46.08

165 g

<0.02 Ω

Mid BP (24 dB)

1.2 mH 14 AWG Cu‑Foil

2

$70.75

480 g

0.07 Ω

​

33 µF Cross‑Cap

2

$15.91

110 g

<0.02 Ω

Tweeter HP (24 dB)

6.8 µF Superior Z‑Cap

2

$50.99

80 g

—

​

0.27 mH 14 AWG Cu‑Foil

2

$31.24

220 g

0.06 Ω

TOTAL / speaker

—

—

≈ $640

≈ 3.2 kg

≤ 0.5 dB

Bill‑of‑Materials – LR4 3‑Way Network (Single Speaker)

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Listening‑Seat Reality Check

Metric

Jantzen LR4 Passive

AC650 Active

XO Ripple

±0.3 dB

±0.05 dB

Group Delay @ 300 Hz

2.1 ms

0 ms

Room EQ Capability

None

±15 dB PEQ + FIR

Upgrade Path

Replace parts

Firmware update

BOM Cost (pair)

~$1,280

Included

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Final Verdict – DSP is Scientifically Better

  • DSP-based active systems like AC650 outperform passive + stereo EQ in every way.
  • Precise filters, no drift, full phase control.
  • Lower distortion, more efficient power use.
  • Adaptable, upgradeable, and more powerful.
  • Professional-grade sound quality at home.

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com

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Sources and References

  • Dynaudio – 'The benefits of an active crossover'
  • ATC Loudspeakers – 'Why go active?' White Paper
  • Audioholics – 'The Loudspeaker Crossover: An Overview'
  • Analog Devices – 'Analog vs. Digital Audio Crossover Design'
  • Gearspace.com – Passive vs active monitor discussions
  • DIYAudio.com – High-end crossover forum threads
  • HiFiCollective.co.uk – Jantzen & Mundorf specs
  • Audio Science Review – DSP vs analog tests
  • BestCarAudio.com – Passive vs active crossover networks

Acoustas Co. 2711 Buford Rd. Unit 217 Richmond, VA 23235 contactus@acoustas.com