What's the best iOS app for adjusting the equalizer on premium Bluetooth headphones?

Marshall Bluetooth is an iOS application tailored for optimizing the audio output of supported Marshall Bluetooth headphones, such as the Major V model. The app stands out for its detailed equalizer customization, allowing users to manually adjust frequency bands or choose from preset sound profiles suited for different music genres or environments. This feature is particularly useful in real-world scenarios like commuting, where noise isolation settings might be preferred, or at home for critical listening sessions that demand clarity in vocals and instruments. Reviews indicate that users appreciate the ability to fine-tune audio, with many reporting improved sound detail and a more immersive experience. Beyond EQ adjustments, the app includes practical tools for firmware updates and battery monitoring, ensuring devices remain up-to-date and functional. However, a limitation is its compatibility with select Marshall products—older models like the Major IV do not support the app, which can frustrate some long-time brand enthusiasts. Occasionally, users note minor connectivity issues when pairing, though these are often resolved with app restarts. For those with compatible gear, Marshall Bluetooth offers a straightforward interface with a design that echoes the brand's iconic aesthetic, making it a reliable choice for audio enthusiasts seeking control over their listening experience without overly complex setups.