Overview

The JBL LSR310S is a studio subwoofer belonging to JBL’s professional LSR series. It combines a 200W Class D amplifier with a 10-inch custom driver, and its down-firing design achieves a nominal low-frequency extension down to 27Hz. The XLF (Extended Low Frequency) setting also accommodates the ultra-low frequency tuning used in dance clubs. It is designed to build an accurate monitoring environment and is intended for seamless integration, especially with JBL’s LSR monitor series.

Scientific Validity

\[\Large \text{0.5}\]

While the official specifications claim low-frequency extension to 27Hz and a maximum SPL of 113dB, third-party measurement data reveals some issues. In particular, the Total Harmonic Distortion (THD) has been observed to exceed 5% in the 30-40Hz range at high volumes, which qualifies as a problematic level under the policy standards. Furthermore, the nominal low-frequency cutoff of 27Hz is a -10dB point; the practical bass extension (-3dB point) is around 33Hz. Its support for professional +4dBu signal levels is commendable, but due to physical limitations, especially concerning distortion, it does not achieve the transparent reproduction quality of amplifiers or DACs.

Technology Level

\[\Large \text{0.7}\]

JBL’s proprietary Slip Stream™ port technology is a rational design that suppresses air turbulence and reduces port noise. The adoption of a 200W Class D amplifier and a professional design with balanced XLR inputs and outputs meets industry standards. However, the overall design is an effective combination of existing technologies rather than a showcase of groundbreaking innovation. Considering that the measured distortion performance is not ideal, the applied technology does not necessarily translate into top-tier acoustic performance, making its technological advancement limited.

Cost-Performance

\[\Large \text{1.0}\]

With a current Japanese market price of 265 USD, this product offers extremely high cost-performance. Studio subwoofers from other major manufacturers with comparable or superior specifications (10-inch driver, 200W class amplifier) are all significantly more expensive. Cheaper alternatives, like the PreSonus Eris Sub 8XT, have smaller drivers (8-inch) or lower power, and thus are not directly comparable in performance. Therefore, this product is effectively the world’s most affordable option for a professional-grade subwoofer with these specifications, representing unparalleled value.

Reliability & Support

\[\Large \text{0.8}\]

JBL is a brand with a long history in the pro audio industry, and its products meet industry-standard reliability. The LSR series is robustly designed for studio use, and a support system is well-established through authorized distributors in Japan. However, the long-term reliability of Class D amplifiers does not yet have the same extensive track record as traditional analog amplifiers. Also, considering its price point, one should not expect the absolute durability of high-end professional equipment.

Rationality of Design Philosophy

\[\Large \text{0.8}\]

The philosophy of designing based on measurable performance and a scientific approach is rational. The Slip Stream™ port and down-firing design are physically sound from an acoustics perspective, and there is a complete absence of unscientific elements or occult claims. The professional specifications also directly contribute to sound quality. However, not all aspects of the design philosophy have culminated in the best possible results, as the measured distortion rates do not reach ideal levels, marking a clear difference from higher-end products. While it achieves a breakthrough in price, there remains room for improvement in performance.

Advice

For users looking to build a low-frequency monitoring environment in a small to medium-sized studio, the LSR310S is an outstanding choice from a cost-performance perspective. The ability to get a professional-spec subwoofer with a 10-inch driver for around 265 USD is a powerful advantage unmatched by other products. It is especially effective when paired with JBL’s LSR series monitors for a seamless system. However, for those who prioritize absolute low distortion and frequency response flatness, this unit’s performance may be insufficient. This product is highly recommended for users who want to take the first step toward accurate bass reproduction while prioritizing cost above all else.

(2025.7.23)