Linn Exaktbox Sub

Adding a subwoofer to a high-quality stereo system is harder to do well than most people expect. The problem is not the subwoofer itself — it is the crossover. A conventional analogue crossover introduces phase shift at and around the crossover frequency, creating a region of the bass where the main speakers and subwoofer are pulling in different directions rather than integrating cleanly. The result is bass that sounds thick, slow, or disconnected from the music, regardless of how well-specified the subwoofer is.

The Exaktbox Sub solves this properly. It provides two channels of Akurate-level Exakt digital crossover and DAC processing, making the whole system — main speakers and subwoofer together — phase linear from the crossover point all the way down to 0Hz. The integration is genuinely seamless in a way that analogue crossovers cannot achieve.

How Exakt Subwoofer Integration Works

In an Exakt system, the signal from the Linn DSM travels via Exakt Link — a digital connection — to the active loudspeakers and any Exaktbox units in the chain. The Exaktbox Sub sits in this signal path and performs the crossover digitally, in the mathematical domain.

The digital crossover has a critical advantage: it can achieve phase-linear crossover behaviour that is physically impossible with an analogue circuit. Rather than the gradual phase rotation of an analogue filter, the Exakt crossover processes the signal in a way that maintains correct phase relationships across the entire frequency range. Main speakers and subwoofer arrive at the listening position with the same timing relationships they had in the original recording.

Additionally, the Exaktbox Sub allows the main speakers and subwoofer to be configured independently, accounting for differences in their physical positions and therefore their distance from the listening position. Getting the time-of-flight relationship correct between main speakers and a subwoofer sitting in a corner is one of the most overlooked aspects of subwoofer setup; the Exaktbox Sub handles it properly.

Configuration Options

The Exaktbox Sub supports two subwoofer configurations:

Stereo subwoofer operation: Two separate subwoofer channels — one for left bass, one for right bass — driven from the two analogue outputs. This configuration retains full stereo imaging in the bass register, which is audible on well-recorded material.

Mono subwoofer operation: Both channels summed and fed to a single subwoofer. This is the more common configuration and is appropriate for most rooms and most subwoofer positions.

The unit connects to the Linn DSM via two Exakt Link inputs, and outputs via balanced XLR or unbalanced phono (RCA) to the subwoofer's amplifier input.

Compatibility

The Exaktbox Sub is compatible with any subwoofer — it outputs a line-level analogue signal that feeds the subwoofer's own amplification. It requires an Exakt-enabled Linn DSM as the source component. If your Linn DSM does not currently have Exakt capability, discuss upgrade options with us before purchasing.

Technical Specifications

Who Is It For?

The Exaktbox Sub is for the Linn Exakt system owner who wants to add a subwoofer to their setup, and wants to do it properly rather than in a way that compromises the performance of the main system. It is also appropriate for anyone who has struggled to integrate a subwoofer into a high-quality stereo system using conventional crossover methods and wants to understand why the result has been unsatisfying.

If you are using passive loudspeakers rather than Exakt-active speakers, the Exaktbox Sub is not the right route — it is specifically an Exakt product. If you have Linn Exakt-active speakers and a Linn DSM with Exakt Link, the Exaktbox Sub is the correct, purpose-built solution.

Buying from Martin's Hi-Fi

Martin's Hi-Fi has been in Norwich since 1968, and the Linn range has been part of what we do for years. We are still family-run — Ted Martin's daughter Elizabeth runs the business today — and we stock only brands we have heard properly and stand behind.

Exakt system configuration — particularly around subwoofer integration and Space Optimisation — benefits from dealer involvement. We can walk through the right setup for your room and system before purchase, and help with configuration and calibration during installation.

Reach them at dave@martinshifi.co.uk, chris@martinshifi.co.uk, info@martinshifi.co.uk, call on 01603 627010, or WhatsApp Dave or Chris directly on 07554 687137. You can read more about who we are and how we work on our Why Martin's page. We are at 85–91 Ber Street, Norwich, NR1 3EY, open six days a week.

Contact: info@martinshifi.co.uk | 01603 627010 | WhatsApp: 07554 687137 | 85–91 Ber Street, Norwich, NR1 3EY