82FHW

LOUDSPEAKER ENCLOSURE DESIGN REPORT
Driver: 82FHMX8-445A
Generated: 2026-04-12
Application: Outdoor hi-fi, bars/hospitality, 2-way home systems
DRIVER SPECIFICATIONS
Code             : 82FHMX8-445A
Description      : 8" Ferrite Mid-Woofer — Hard-Anodized Aluminum Cone
Nominal Impedance: 8 Ω
AES Power        : 60 W
Continuous Power : 120 W
Peak Power       : 240 W

Fs               : 42 Hz
Re               : 5.7 Ω
Qes              : 0.76
Qms              : 3.1
Qts              : 0.61
Vas              : 33.6 L
Sd               : 213.8 cm²
Sensitivity      : 88.31 dB (1 W / 1 m)
Mms              : 28.3 g
Rms              : 2.41 kg/s
Cms              : 0.51 mm/N
Bl               : 7.56 T·m
Le               : 0.47 mH
Xmax             : 5.45 mm (one-way, peak)
Xmech            : 10.45 mm

Voice Coil       : 38 mm, Copper wire, Aluminum former
Cone / Dustcap   : Hard-anodized aluminum
Surround         : NBR rubber (UV-stabilized)
Spider           : Nomex
Basket           : Aluminum (coated)
Magnet           : Ferrite
DERIVED PARAMETERS
Volume displacement
  Vd = Sd × Xmax = 213.8 cm² × 0.545 cm = 116.5 cm³

Inductance rolloff onset
  f_Le = Re / (2π × Le) = 5.7 / (2π × 0.00047) ≈ 1,930 Hz

Cone beaming onset
  r_cone = √(Sd / π) = √(213.8 / 3.14159) = 8.25 cm
  f_beam = c / (π × r_cone) = 34,400 / (3.14159 × 8.25) ≈ 1,327 Hz

Working band        : ~50 Hz – 1,300 Hz
Tweeter crossover   : 1.5 – 3.0 kHz (acoustic target)
  Le onset at ~1,930 Hz provides a natural HF roll-off before
  the crossover network; a 2nd-order passive network at 2.0–2.5 kHz
  is the typical design point.

Maximum SPL (anechoic, 1 m)
  At 60 W AES   : 88.31 + 10·log₁₀(60)  = 88.31 + 17.8 = 106.1 dB
  At 120 W cont : 88.31 + 10·log₁₀(120) = 88.31 + 20.8 = 109.1 dB
  In-room / bar : add ~3–6 dB room gain below 80 Hz
ENCLOSURE RECOMMENDATION
Qts = 0.61 → Sealed (acoustic suspension) is the primary
recommendation. The manufacturer explicitly states that
parameters are optimized for sealed enclosures. Room gain in
home and bar environments further extends perceived bass.

Vented (bass reflex) alignments are provided below as an
alternative for high-output bar and outdoor applications
where maximum SPL and lower excursion at moderate levels are
prioritized over transient accuracy. Vented boxes are
significantly larger than their sealed counterparts.
SEALED ENCLOSURE ALIGNMENTS
Formula: Vb = Vas / ((Qtc / Qts)² − 1)
         fc  = Fs × (Qtc / Qts)
         f-3dB: u = [−(2 − 1/Qtc²) + √((2 − 1/Qtc²)² + 4)] / 2
                Ω = √u ;  f-3dB = Ω × fc

┌────────────────────────────────────────────────────────────────────┐
│ Alignment │ Vb (net) │ Qtc  │   fc    │ f−3dB  │ Character        │
├───────────┼──────────┼──────┼─────────┼────────┼──────────────────┤
│     A     │   20 L   │ 1.00 │  68.9 Hz│  54 Hz │ Flat, monitor    │
│     B     │   15 L   │ 1.10 │  75.7 Hz│  57 Hz │ Compact 2-way    │
│     C     │   10 L   │ 1.27 │  87.5 Hz│  63 Hz │ Bookshelf / sat  │
└────────────────────────────────────────────────────────────────────┘

--- Alignment A — 20 L sealed / Qtc = 1.00 ---
  Vb = 33.6 / ((1.00/0.61)² − 1) = 33.6 / 1.687 = 19.9 L → 20 L
  fc = 42 × (1.00/0.61) = 68.9 Hz
  f-3dB: 2−1/Qtc²=1.000; √(1+4)=2.236; u=(−1+2.236)/2=0.618; Ω=0.786
         f-3dB = 0.786 × 68.9 = 54 Hz

  Target applications: Floor-standing hi-fi 2-way; large stand-mount
  monitor; bar or restaurant satellite enclosure placed near walls.
  Flat bass response with no overhang; preferred for studio monitors
  and audiophile stereo. With 3–5 dB room gain in a domestic room,
  perceived bass extends to ~45 Hz.

--- Alignment B — 15 L sealed / Qtc = 1.10 ---
  Vb = 33.6 / ((1.10/0.61)² − 1) = 33.6 / 2.252 = 14.9 L → 15 L
  fc = 42 × (1.10/0.61) = 75.7 Hz
  f-3dB: 2−1/1.21=1.174; √(1.379+4)=2.319; u=(−1.174+2.319)/2=0.573; Ω=0.757
         f-3dB = 0.757 × 75.7 = 57 Hz

  Target applications: Compact 2-way stand-mount; bar satellite
  speaker; outdoor column speaker housing; 2-way portable enclosure.
  Mild low-bass shelf boost (~1–2 dB around 75–100 Hz) gives a
  subjectively warm, full bass in domestic rooms. A practical balance
  between box size and low-frequency extension.

--- Alignment C — 10 L sealed / Qtc = 1.27 ---
  Vb = 33.6 / ((1.27/0.61)² − 1) = 33.6 / 3.335 = 10.1 L → 10 L
  fc = 42 × (1.27/0.61) = 87.5 Hz
  f-3dB: 2−1/1.613=1.380; √(1.904+4)=2.430; u=(−1.380+2.430)/2=0.525; Ω=0.725
         f-3dB = 0.725 × 87.5 = 63 Hz

  Target applications: Bookshelf speaker; compact outdoor enclosure;
  under-bar fill speaker; satellite in a subwoofer-satellite system.
  Prominent bass shelf boost (~3 dB around 80–100 Hz); perceived bass
  sounds full in small rooms due to coincident room gain.
  High-pass filter mandatory: 80 Hz, 12–24 dB/oct (DSP or passive
  Butterworth) to prevent over-excursion below fc.
  Best paired with subwoofer crossed over at 80–120 Hz.

--- Notes for all sealed alignments ---
  • Recommended system-level high-pass filter: 40–80 Hz (selection
    depends on alignment and application).
  • Room gain adds 3–6 dB below 80 Hz in typical home/bar rooms;
    anechoic f-3dB values above will be 1.0–1.5 octaves higher than
    the in-room perceived bass extension.
  • Zobel network improves crossover flatness where passive networks
    are used: R_z = Re = 5.7 Ω ; C_z = Le / Re² = 0.47e-3 / 32.49
    = 14.5 μF → use 15 μF, 100 V non-polar standard value.
VENTED ENCLOSURE ALIGNMENTS (HIGH-OUTPUT OPTION)
For bars, outdoor installations, and applications where
maximum SPL and reduced cone excursion at moderate levels
are prioritized. Boxes are 1.5–3× larger than sealed.

Port: 75 mm round (Ap = 44.18 cm²)
  Port velocity limit: ≤ 17 m/s (hi-fi / install standard)

Leff = (Ap × c²) / (4π² × Fb² × Vb)
  c = 34,400 cm/s ; c² = 1,183,360,000 cm²/s²
  4π² = 39.478

Port velocity: v_peak = Vd × 2π × Fb / Ap
  Vd = 116.5 cm³ = 1.165 × 10⁻⁴ m³ ; Ap = 4.418 × 10⁻³ m²

┌──────────────────────────────────────────────────────────────────────┐
│ Alignment │ Vb (net) │  Fb   │ 75mm Port Length │ Port Velocity     │
├───────────┼──────────┼───────┼──────────────────┼───────────────────┤
│     A     │   35 L   │ 48 Hz │      164 mm      │   7.9 m/s  ✓     │
│     B     │   50 L   │ 40 Hz │      166 mm      │   6.6 m/s  ✓     │
│     C     │   70 L   │ 33 Hz │      174 mm      │   5.5 m/s  ✓     │
└──────────────────────────────────────────────────────────────────────┘

Port length calculations (75 mm round port):
  Alignment A: Leff = (44.18 × 1,183,360,000) / (39.478 × 2304 × 35,000)
                    = 5.228×10¹⁰ / 3.183×10⁹ = 164 mm
  Alignment B: Leff = (44.18 × 1,183,360,000) / (39.478 × 1600 × 50,000)
                    = 5.228×10¹⁰ / 3.158×10⁹ = 166 mm
  Alignment C: Leff = (44.18 × 1,183,360,000) / (39.478 × 1089 × 70,000)
                    = 5.228×10¹⁰ / 3.010×10⁹ = 174 mm

Port engineering note: All three vented alignments produce
near-identical port lengths (164–174 mm). Larger box volume and
lower tuning frequency cancel each other in the Helmholtz equation
— lower Fb² is offset by proportionally larger Vb. A single
75 mm × 170 mm port tube (with minor end-trimming) serves all
three tunings, simplifying production tooling.

--- Vented Alignment A — 35 L / Fb = 48 Hz ---
  Tuning above Fs (48 Hz vs Fs 42 Hz). Modest bass extension with
  strong output protection above the port tuning frequency. Clean
  output from ~50 Hz in a compact(ish) vented cabinet. Good for
  bar fill speakers and outdoor stereo where sub-50 Hz bass is
  not required.

--- Vented Alignment B — 50 L / Fb = 40 Hz ---
  Near-Fs tuning. Extended response to ~38 Hz (4th-order rolloff
  below Fb). Preferred for high-quality outdoor stereo or bar
  stereo where ~40 Hz bass reproduction is required without a
  separate subwoofer.

--- Vented Alignment C — 70 L / Fb = 33 Hz ---
  Below-Fs tuning. Maximum bass extension into the upper 30s Hz.
  Large box for an 8" driver; suited for floor-standing or tower
  vented enclosures in bar or patio stereo systems.
  Mandatory high-pass filter at 25–30 Hz to protect driver
  below the port roll-off (4th-order slope begins below Fb).
CROSSOVER AND SYSTEM INTEGRATION
Crossover to tweeter (acoustic target): 1.5 – 3.0 kHz
  f_beam = 1,327 Hz (cone directivity increases above this)
  f_Le   = 1,930 Hz (inductive roll-off onset)

Recommended crossover order: 2nd-order (12 dB/oct) minimum;
  3rd or 4th-order preferred at 2.0–2.5 kHz for controlled
  off-axis response above 1.3 kHz. Aluminum cone maintains
  pistonic response closer to f_Le than paper or PP cones of
  equal diameter, allowing a higher crossover frequency if
  directivity is not a primary concern.

Zobel network (for passive crossover precision):
  R_z = 5.7 Ω (standard 5.6 Ω resistor acceptable)
  C_z = 15 μF, 100 V non-polar (nearest standard to 14.5 μF)
  Place across driver terminals inside the enclosure.
MATERIALS AND DURABILITY NOTES
  • Hard-anodized aluminum cone: rigid, damp-proof, UV-stable;
    extends HF pistonic range; resists condensation and salt air.
  • NBR rubber surround: UV-stabilized; rated −30 °C to +70 °C;
    suitable for all-season outdoor and coastal installations.
  • Aluminum basket (coated): corrosion-resistant; structurally
    rigid; reduces chassis resonance in portable enclosures.
  • Nomex spider: heat-resistant; suited for sustained high-power
    bar operation in warm ambient environments.
  • Ferrite magnet: thermally stable; no demagnetization risk
    in normal audio operating temperature ranges.