The Sennheiser HD 660 S is an open-back, over-ear headphone that delivers a natural and balanced sound signature, making it perfect for audiophiles seeking precise music reproduction. The open-back design allows for a spacious soundstage and accurate imaging, while the comfortable ear pads and headband ensure long listening sessions without fatigue. The HD 660 S features new and improved transducers that provide lower harmonic distortion, resulting in a more detailed and transparent sound. The detachable cables with high-quality connectors ensure a secure connection and easy replacement if needed. However, the open-back design may not be suitable for use in noisy environments or when privacy is required, as sound leakage can occur. Additionally, the HD 660 S may not be the most portable option due to its size and lack of folding mechanism. Despite these minor drawbacks, the Sennheiser HD 660 S offers an exceptional listening experience for audiophiles seeking high-end headphones under $500.

The HIFIMAN Sundara is a pair of high-quality planar magnetic headphones that deliver exceptional detail and clarity, making them perfect for audiophiles seeking precise music reproduction. The open-back design provides a natural and spacious soundstage, while the lightweight diaphragm ensures fast response and minimal distortion. The comfortable headband and ear pads are made from high-quality materials, ensuring long listening sessions without discomfort. The headphones also feature a detachable cable for easy replacement or customization. One downside to the HIFIMAN Sundara is that they may not be suitable for use in noisy environments due to their open-back design. However, for those seeking an immersive and accurate listening experience in a quiet setting, the Sundara is an excellent choice.

The Focal Elegia is a pair of closed-back circumaural headphones that offer excellent sound isolation and precision, making them perfect for audiophiles who want to enjoy their music without any distractions. These headphones feature Focal's proprietary M-shaped dome drivers, which deliver a balanced and detailed sound signature with tight bass, clear mids, and smooth highs. The memory foam earpads and headband ensure a comfortable fit, while the aluminum yoke and leather headband provide durability and a premium feel. The Elegia also comes with a detachable cable and a carrying case for added convenience. One downside to the Focal Elegia is that they may not be the best choice for those who prefer an open-back design, as the closed-back design can make the soundstage feel slightly narrower. However, the excellent sound isolation and precision make them a great choice for audiophiles who want to focus on their music without any distractions.

The Meze Audio 99 Classics are a perfect blend of style and performance, offering a balanced sound signature that caters to a wide range of music genres. These headphones feature handcrafted wooden ear cups, giving them a unique and elegant appearance. The 40mm dynamic drivers deliver a clear and detailed sound, while the closed-back design provides passive noise isolation, allowing you to enjoy your music without distractions. The self-adjusting headband and soft ear pads ensure a comfortable fit for extended listening sessions. However, the Meze Audio 99 Classics may not be the best choice for those who prefer a more analytical sound or require a completely neutral frequency response. But for audiophiles who appreciate a touch of style and a well-rounded sound signature, these headphones are an excellent choice under $500.

The Audio-Technica ATH-R70x is a pair of professional open-back reference headphones that deliver exceptional sound quality and comfort. These headphones are designed for audio professionals and audiophiles who demand accurate sound reproduction and a natural listening experience. The open-back design allows for a spacious soundstage and precise imaging, while the 45mm drivers with neodymium magnets provide excellent detail and clarity. The lightweight construction and breathable fabric earpads ensure long-lasting comfort during extended listening sessions. One downside to the open-back design is that it may not be suitable for use in noisy environments, as it allows for sound leakage and minimal isolation. However, for those seeking an immersive and accurate listening experience in a quiet setting, the Audio-Technica ATH-R70x is an excellent choice.

The Grado SR325e is a pair of handcrafted, open-back headphones that offer a unique retro design and exceptional sound quality. These headphones are part of Grado's Prestige Series, which is known for its attention to detail and commitment to high-quality audio reproduction. The SR325e features a metal housing that minimizes distortion and enhances the overall sound clarity. The open-back design provides a spacious soundstage and natural sound, making it perfect for audiophiles who appreciate an immersive listening experience. However, the open-back design also means that these headphones may not be suitable for use in noisy environments or for those who require sound isolation. Additionally, the retro design may not appeal to everyone's taste. Despite these minor drawbacks, the Grado SR325e is an excellent choice for those seeking high-end audiophile headphones with a unique design and exceptional sound quality.

The AKG K712 Pro headphones are designed for professional mixing and mastering, offering a spacious soundstage and precise audio reproduction. These open-back headphones feature large over-ear cups with comfortable velour ear pads, ensuring long listening sessions without fatigue. The lightweight design and self-adjusting headband provide a secure and comfortable fit. The K712 Pro's 3D-foam ear pads and genuine leather headband ensure maximum comfort during long listening sessions. The headphones come with a detachable cable and a premium carrying bag for easy storage and transportation. While the open-back design provides a spacious soundstage, it also means that these headphones are not ideal for use in noisy environments or for those who require sound isolation. However, for audiophiles seeking an immersive listening experience with accurate sound reproduction, the AKG K712 Pro is an excellent choice.

The Sony MDR-Z7M2 is a high-resolution audio headphone that delivers exceptional sound quality and comfort. It features an aluminum-coated Liquid Crystal Polymer (LCP) diaphragm, which provides a wide frequency range and precise sound reproduction. The closed-back design offers excellent noise isolation, making it perfect for listening in noisy environments or during long sessions. The ergonomic ear pads and headband ensure a comfortable fit, while the detachable cable allows for easy replacement or customization. One downside of the Sony MDR-Z7M2 is its relatively high price compared to other options on this list. However, the premium build quality, exceptional sound performance, and comfortable design make it a worthy investment for audiophiles seeking a high-end listening experience under $500.