The Truth About High-Level Inputs on Subwoofers

Why Our Subwoofers Use Low-Level Inputs Only

At Arendal Sound, all our subwoofers are designed with Low-Level inputs only:

• RCA on the 1961 Series Subwoofers

• XLR & RCA on the 1723 Subwoofers

This design choice is intentional, and here’s why.

What high-level inputs are

Some subwoofers on the market offer High-Level (speaker-level) inputs, where you connect the same speaker cables that drive your main speakers into the subwoofer. The marketing pitch is that this creates “better synergy” between the sub and your main speakers, since both are receiving the identical amplifier signal.

In reality, this isn’t how it works. A subwoofer’s amplifier and internal filters require a low-level signal. High-Level inputs simply step the signal down internally using resistor dividers or buffers. The subwoofer never processes the speaker-level signal directly.

Why Low-Level is superior

• Cleaner signal path – With Low-Level inputs, the preamp signal goes straight into the sub’s filters and amplifier, without unnecessary conversion stages.

• Better signal-to-noise ratio – Keeping the signal at line level avoids additional noise and distortion introduced during conversion.

• No amplifier loading risks – High-Level inputs must be carefully isolated to avoid loading the main amplifier or causing interference. If poorly implemented, they can even damage the amplifier. With Low-Level, this is never a concern.

What about “synergy”?

The claim that High-Level connections provide better synergy is largely marketing. Once the speaker-level signal is reduced to line level inside the sub, there is no sonic advantage over feeding the subwoofer directly with a clean Low-Level signal. Proper setup and integration, including placement and calibration, matter far more than connection type.

When your amplifier has no sub output

In the rare case that your amplifier has no dedicated subwoofer or preamp output, you can still use your subwoofer. The solution is to add a High-Level to Low-Level converter, which safely converts your speaker outputs to a proper Low-Level signal for the sub. For example: Speaker Level Subwoofer Adapter