To add to the point above: if youre serious about accuracy for a commercial, you should look into the Sony MDR-CD900ST Studio Monitor Headphones. Theyre the standard in Japanese studios but often overlooked elsewhere. I've found them much more honest than the 7506s, especially in the mid-range where dialogue lives.

• Weight: They are incredibly light, so you wont get that head clamp feeling during a 10-hour edit session.
• Sound Signature: Very flat and clinical, which is basically what you need to catch audio errors before your final export.
• Repairability: You can actually rebuild these from scratch because replacement parts are widely available online. They usually run around $200, so youll have plenty of cash left over to grab some Yaxi STPad2 Earpads for Sony MDR-CD900ST to make them even more plush. It basically solves any comfort issues while keeping the sound professional.

Most editors start with the Sony MDR-7506 Professional Large Diaphragm Headphones because they are legendary, but unfortunately, they were not as good as expected for my modern workflows. I had issues with the high-end being too piercing and the ear pads flaked everywhere after just a few months. It was honestly a disappointing experience. With a $400 budget, you should definitely grab the Sony MDR-MV1 Open-Back Reference Monitor Headphones. These are much more methodical for spatial audio and the open-back design is a lifesaver for long sessions. They wont hurt your head after three hours like the older ones do. Its a much better investment for a pro commercial edit next week... definitely worth the extra cash.

Just caught up on this thread while I'm waiting for a 4K render to finish. I spent years sticking to the old standards because they were cheap and good enough, but a few years ago I had a client complain about a hiss in the audio that I simply couldnt hear on my budget gear. Since then, ive been pretty picky about what I put on my head for a 10-hour day. I actually switched over to the Sony MDR-M1 Reference Closed-Back Headphones recently and it changed things quite a bit for my workflow.

• MDR-M1: These are basically the new closed-back standard. The isolation is solid if you're working in a studio with others around. Plus, the frequency response is way more balanced than the older models. Biggest pro is the comfort tho, they dont squeeze your head like a vice during those long nights.
• Sony MDR-MV1 Open-Back Reference Monitor Headphones: I demoed these for a week and they are basically air. If you're doing spatial audio or need a massive soundstage for a commercial, these win easily. But man, everyone in the room will hear your timeline because they bleed sound like crazy. If your commercial edit involves a lot of precise dialogue cleaning and you're in a shared space, the M1 is probably the safer bet. If you're alone in a quiet room and want to feel like you're not wearing headphones at all, the MV1 is hard to beat for that $400 budget. Just my two cents from being in the trenches with these things...