Review: Stax SR-L500MK2 – Sleeper Hit

Review: Stax SR-L500MK2 – Sleeper Hit

Our comprehensive review will review the Stax SR-L500MK2, the latest iteration of an iconic model from the renowned electrostatic headphone specialist. Over 36 years ago, STAX made its debut with the SR-Lambda series. Now, the next generation has arrived in the form of the SR-L500MK2. Building upon the exceptional sound of its predecessors, this model introduces a fresh enclosure design.

The STAX SR-L500MK2 is an advanced Earspeaker, boasting durable stainless fixed electrodes and a meticulously chosen thin-film diaphragm. Immerse yourself in a harmonious blend of refined treble, soothing midrange tones, and immersive bass, achieving the pinnacle of audio balance. Let’s dive furthermore with us!

I. Product Tech Specifications

  • Type: Push-Pull Open Back Oval Electrostatic Ear speaker Headphone
  • Frequency Response: 7 – 41,000Hz
  • Electrostatic Capacitance: 110pF (including cable)
  • Impedance: 145k Ω (including cable, at 10kHz)
  • Sound Pressure Sensitivity: 101dB / 100V r.m.s. 1 kHz
  • Maximum Sound Pressure: 118dB / 400Hz
  • Bias Voltage: 580V DC
  • Left & Right Identification: “L” and “R” are indicated on the arc assembly Left channel cable is marked with a solid line. The right channel is marked with a dotted line.
  • Ear Pads: High-quality synthetic leather
  • Cable: HiFC parallel 6-strand, low-capacity special wide copper cable, 2.5m full length
  • Weight: 351g without cable / 471g with cable
  • Price: $830.00 via Offical Website

II. Design of Stax SR-L500MK2

Built Quality

The SR-L500MK2 bears a striking resemblance to the build quality of its counterparts, the SR-L700MK2 and SR-L300. However, it is unfortunate that the overall construction falls short of expectations, exhibiting subpar quality. Using plastic for most components, including the headband arc, gives a sense of fragility. It might be worth exploring the possibility of adopting the headband design, or a similar one, from the SR-X9000, as it showcases Stax’s ability to create a more robust headband option for their Lambda models.

During the experience with the product, noticeable creaking and popping sounds while putting on and wearing the headphones raised concerns regarding their durability. On a positive note, the earpads stand out as an exception to the general trend of poor build quality. Crafted from soft and comfortable leather, they exhibit commendable craftsmanship.

III. Performance


For those unacquainted with electrostatic technology, it is essential to note that these headphones operate differently from standard headphones, employing a significantly higher voltage (while maintaining a lower current due to their high impedance). Safety concerns should not be excessive, but it is crucial to use a dedicated amplifier.

Stax SR-L500MK2 Review

Traditionally, electrostatic drivers were renowned for delivering lower distortion and higher resolution than dynamic and planar-magnetic counterparts. However, it is worth mentioning that planar-magnetic and dynamic headphones have made remarkable strides, rivaling electrostatic headphones in terms of resolution. Nevertheless, electrostatic headphones possess a unique quality of effortlessly producing an airy sound, which remains difficult for other technologies to replicate.

It is essential to acknowledge that electrostatic headphones do have their limitations. For instance, achieving a sense of macro dynamics can prove challenging with these drivers.

Sound Quality

The SR-L500MK2, like other members of the Lambda series, possesses distinct characteristics that define its sound signature. It offers a lightweight and ethereal audio experience, accompanied by a slightly recessed lower midrange and bass, along with a peak at 1.5kHz.

These qualities can be captivating and addictive, creating a unique presentation where sounds seemingly materialize from the surrounding air in a truly remarkable manner. However, it is essential to note that such a presentation may not appeal to everyone, as it can sometimes lack impact, body, and dynamics.

Compared to the more affordable SR-L300, the SR-L500MK2 exhibits greater balance across the entire frequency range. It boasts improved midrange tuning, more articulate bass, and smoother, less edgy treble. Additionally, it demonstrates significantly enhanced resolving power.

Sonically, the SR-L500MK2 stands out as one of the most well-balanced offerings among the modern Lambdas, particularly in midrange tuning. It competes head-to-head with the SR-L700 regarding technical prowess while maintaining a more even and consistent tuning.


The SR-L500 headphones provide unmatched resolution and detail in the sub-$1,000 range, impressing those transitioning from mid-fi dynamic headphones. They maintain exceptional clarity even in complex musical passages, with distinct layers and real instruments. The SR-L500 competes with higher-priced headphones in detail retrieval.

The imaging performance is commendable, though the soundstage size is not exceptionally large compared to other models like the SR-L700 and Lambda Pro. The soundstage of the SR-L500 feels two-dimensional, with sounds appearing to come from around the facial area.

The SR-L500 sacrifices dynamics for its remarkable qualities, offering reduced dynamic range and slightly compressed volume transitions. Prioritizing hearing health is important. While higher-priced electrostatic headphones like the Stax SR-007 may have more convincing dynamics and equal or superior resolution, the SR-L500’s price point makes it a worthwhile trade-off.


The SR-L500, like other Lambda models, faces bass reproduction challenges due to driver limitations and the inclusion of a bass port in the new design. Previous Lambda models had a flat bass response, but the new design incorporates a small port, resulting in slight mid-bass elevation and roll-off.

Plugging the ports with Blu-Tak can restore perfect bass extension, as the SR-L500’s bass frequency response may be lacking without this modification. The bass has an ethereal texture, which may disappoint those seeking dynamic impact. It is less bothersome for classical or jazz but falls short for genres like EDM or bass-heavy music.


The SR-L500, like other Lambda models, has a slightly deviated midrange tuning from complete neutrality. A subtle recession in the lower midrange contributes to a clear sound with a slight lack of body. The upper midrange has a laid-back character, creating a relaxed sound presentation.

There is a forwardness around 1.5 kHz, described as “honky” or “shouty,” though I find “glassy” to be more fitting. These midrange colorations are noticeable with instruments like the piano, where tonal balance is crucial. Certain notes in the upper registers may sound overly emphasized or wet, though it is less pronounced in the SR-L500.

Recordings with emphasis around 1.5 kHz may have a nasal or “washed-out” quality. Despite these characteristics, the SR-L500 has an excellent midrange, with fewer prominent “flaws” than other Lambdas, allowing clarity and lucidity to shine through. The result is a wonderfully clear and well-balanced midrange presentation.


The SR-L500, like other electrostatic headphones, has impressive treble with a slight “spiciness” depending on personal tolerance. The SR-L500 delivers resolving and clean treble with minimal distortion, presenting details effortlessly. There is a subtle emphasis on high-frequency air, enhancing the realism of sound reproduction.

However, the SR-L700 significantly surpasses the SR-L500 in treble performance. The L500, while excellent for its price range, may have slight graininess and less refinement compared to the L700. Note that this comparison is against a headphone twice its price. Compared to headphones in their price range, the SR-L500 excels, offering exceptional treble quality and resolution.

IV. The Advantages and Disadvantages

Stax SR-L500MK2 Review


  • Unmatched resolution for their price range
  • The crisp and clear midrange
  • Enchanting and captivating sound
  • Well-balanced sonic representation
  • Exceptional value compared to other Lambdas
  • Impressive imaging capabilities


  • Bass can sound rolled-off and bloated (can be addressed with a simple modification)
  • Below-average build quality
  • Limited dynamic range


The SR-L500MK2 deserves more attention despite its lower popularity than other Lambda models, often attributed to marketing and “middle child syndrome.” In certain areas, it even outperforms the SR-L700. With an excellently-tuned midrange and impressive resolution across the frequency spectrum, the SR-L500MK2 offers a well-balanced package.

It is a strong contender for daily use among electrostatic headphones. Priced at USD$830, the SR-L500MK2 provides excellent value, surpassing other sub-$1000 headphones in resolution and offering an outstanding sonic presentation. It’s important to note that as electrostatic headphones, they cater to specific sonic preferences.

Some listeners may find the sound thin or dry, and the need for an expensive amplifier adds to the cost. Nevertheless, for those interested in exploring electrostatic headphones, the SR-L500MK2 is highly recommended. They outshine cheaper options and are an excellent entry point into electrostatic audio.

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