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AudioControl SPK-8S4 Review: Specifications, Fitment and Comparisons

Writer: Akansh Garg
Akansh Garg
3 days ago
5 min read

Quick summary: the buying decision

The SPK-8S4 is an 8-inch Spike Series subwoofer with a single 4-ohm voice coil, rated at 350 W RMS / 500 W max. It needs an enclosure and a mono amplifier; AudioControl publishes both sealed and ported box recommendations, which makes it straightforward to build or order a box that suits the driver. Mounting depth is 109 mm (4.291 in), so check the space behind the baffle before you commit.

AudioControl SPK-8S4: what it is

The AudioControl SPK-8S4 is an 8-inch Spike Series subwoofer with a single 4-ohm voice coil, rated at 350 W RMS and 500 W max. A high-excursion design and a 3-layer high-temperature voice coil former deliver deep, controlled bass, and a removable grille is included.

Spike Series subwoofers are high-excursion, single 4-ohm designs with a fibre matrix paper cone with mica coating, a 3-layer high-temperature voice coil former, a dual damping system, a dual dust cap for enclosure compression control and a removable grille. AudioControl's Altitude monoblocks offer a Spike Mode for running three of them together.

Official AudioControl SPK-8S4 product photograph

Key features

  • High-excursion design for ultra-low bass

  • Fibre matrix paper cone with mica coating

  • 3-layer high-temperature voice coil former for serious power handling

  • Dual damping system for linear bass and dual dust cap system for enclosure compression control

  • Efficient heavy-duty motor; removable subwoofer grille included

Specifications explained

The SPK-8S4 is rated at 350 W RMS / 500 W max (single 4 ohm) with a 2.0 in (50.8 mm) voice coil. AudioControl quotes a 30 – 500 Hz frequency response and a driver displacement of 0.05 cu ft (1.44 L), which you add to the box's net volume when building.

Fitment: overall diameter 214 mm (8.425 in), cut-out 184 mm (7.25 in), mounting depth 109 mm (4.291 in) and mounting height 14 mm without grille, 30 mm with grille.

Full specifications as published by AudioControl:

  • Model: SPK-8S4

  • Type: 8 in single voice coil subwoofer driver

  • Size: 8 in

  • Impedance: Single 4 ohm

  • Power handling (Pe): 350 W RMS / 500 W max

  • Frequency response: 30 – 500 Hz

  • Voice coil diameter: 2.0 in (50.8 mm)

  • Displacement: 0.05 cu ft (1.44 L)

  • Overall diameter: 214 mm (8.425 in)

  • Cut-out diameter: 184 mm (7.25 in)

  • Mounting depth: 109 mm (4.291 in)

  • Mounting height: 14 mm without grille, 30 mm with grille

  • Motor diameter (with cover): 141 mm (5.55 in)

  • Sealed enclosure: 0.49 cu ft net; 14.5 x 10 x 10 in external (W x H x D); F3 69 Hz; Qtc 0.86

  • Ported enclosure: 0.89 cu ft net, tuned to 40 Hz; 23 x 11.5 x 12 in external; port 1.75 x 10 in, 28 in long; F3 34 Hz

  • Enclosure note: Recommended volumes exclude driver and port displacement

  • In the box: SPK-8S4 subwoofer, manual, warranty card

Enclosure: what AudioControl recommends

AudioControl's recommendations for the SPK-8S4:

  • Sealed: 0.49 cu ft (13.9 L) net; 14.5 x 10 x 10 in external (W x H x D); F3 69 Hz; Qtc 0.86

  • Ported: 0.89 cu ft (25.2 L) net, tuned to 40 Hz; 23 x 11.5 x 12 in external; port 1.75 x 10 in, 28 in long; F3 34 Hz

AudioControl notes that the recommended volumes exclude driver and port displacement, so add those when you calculate the internal size.

A sealed box gives tighter, more controlled bass and needs less space; a ported box plays louder and lower around its tuning frequency but is usually larger and needs a subsonic filter to protect the driver below tuning. Seal and brace the box well, and keep it away from rattling trim.

Wiring and amplifier matching

With a single 4-ohm voice coil, one subwoofer presents 4 ohm, two in parallel present 2 ohm and three in parallel present 1.33 ohm. One SPK-8S4 at 4 ohm suits the A800.1 (400 W at 4 ohm, gain set to stay within 350 W RMS). Two in parallel (2 ohm) on the EPIC1000 get about 350 W each (700 W at 2 ohm). Three in parallel (1.33 ohm) can run from an Altitude monoblock in Spike Mode, for example the A800.1 (800 W at 1.33 ohm, about 267 W each).

Set the amplifier gain with a test tone or an oscilloscope rather than by ear, and use the low-pass filter to blend the subwoofer with the front speakers.

AudioControl SPK-8S4, alternate view

How it compares

Related AudioControl subwoofers at VA3 Car Studio:

Price and value in India

At the time of writing (October 2026), VA3 Car Studio lists the SPK-8S4 at ₹29,740, 15% below the MRP of ₹34,990. Remember to budget for an enclosure and a matched amplifier; the driver price is only part of the total. Prices can change, so the product page always shows the current price.

Verdict: who should shortlist the SPK-8S4

The SPK-8S4 suits listeners who want deep, controlled bass with clear published box data, and it pairs neatly with the Altitude monoblocks' Spike Mode. For a ready-made option, look at the loaded SPK-V12.

Real-world reviews and limitations

We have not yet published a VA3 installation report for the SPK-8S4. The figures in this review are AudioControl's published specifications, not our own measurements, and real-world results depend on the enclosure, the cabin and the tune. If you have used one, we would welcome your feedback.

Frequently asked questions

What enclosure does AudioControl recommend for the SPK-8S4?

Sealed: 0.49 cu ft (13.9 L) net; 14.5 x 10 x 10 in external (W x H x D); F3 69 Hz; Qtc 0.86. Ported: 0.89 cu ft (25.2 L) net, tuned to 40 Hz; 23 x 11.5 x 12 in external; port 1.75 x 10 in, 28 in long; F3 34 Hz.

How much power does the SPK-8S4 need?

It is rated at 350 W RMS / 500 W max; an amplifier delivering close to the RMS rating at your final impedance is the usual target.

How should I wire the SPK-8S4?

It has a single 4-ohm voice coil: one sub is 4 ohm, two in parallel are 2 ohm and three in parallel are 1.33 ohm.

What mounting depth does the SPK-8S4 need?

109 mm (4.291 in), with a 184 mm (7.25 in) cut-out.

Sources, pricing and related reading

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