If you still want to use those HD600 and are into DIY, you can buy a matched set of drivers from sennheiser and replace those old drivers. Also if you feel comfortable and have the time, do open up the headphones and check if the drivers don't have any foreign materials on them, like hairs etc, as that kind of stuff can impact driver performance. Yes, cleaning IEMs is certainly a thing, they do get clogged as time goes by. Have my best regards and enjoy your music. 🎩

Being young doesn't really matter as you can also damage your hearing if exposed to loud sounds, but I digress. Regarding channel imbalance. If your amplifier uses old school potentiometers channel balance is certainly a thing. So you indeed need to test that imbalance with other sources. Also I have been enjoying music since my teens and I'm now in my forties, imbalance with headphones was a pretty rare thing for me, as for IEMs besides the rare QC thing I never had that kind of problems. I know it's a long shot but you should test your amplifier section for DC offset...most amps filter it but one is never too cautious as it can ruin gear.

Same here.

Yea, something is not OK. I replied on another instance but I cant read it. Oh well. Hope someone fixs it. Almost looks like a shadow ban.

Very cool collection!

You sure because I'm using sdf rn.

For a indepth reading (and somewhat boring if you are not in to it) I also recommend this https://habr.com/en/articles/456182/ Bluetooth is a complex beast.

My dad is recovering from cancer and it was a hard fight, I sincerely wish the best for Stallman.

My last DAP is a Sony A35 with a firmware mod and with the unlocked amplifier flag but I rarely use it these days. Make no mistake that thing sounds wonderful and I actually use it on my desktop rig everytime I want to play meme high resolution songs. The modded firmware also lets me use it as a Bluetooth receiver/DAC, but I rarely do it. With that out of the way, I think a DAP is only worth it if you have IEMs or headphones that can take the full potential from it. Imo usually stuff way above 300USD. If you listen to music from streaming services (lossless or not) just take the money you would spend on the DAP and buy a better smartphone that can be used with a simple passive USB C to 3.5mm adaptor, or if you enjoy dongles get a simple DAC. So my answer is not worth it unless you have really great IEMs. (Edit for grammar)

Did you check with an audiologist afterwards? If you are lucky that problem might get better over time. There's many types of hearing damage and not all is permanent. Best regards.

When I was a teen I would literally spend all my day with earphones on, with music actually very loud (but not dangerously loud) guess I was lucky.

I worked in construction for a long time, and everytime I had to work with power tools I would just use some diy earplugs made with toilet paper, while it might sound hilarious it actually saved my hearing in the long run, for the ones who might ask why I didn't use correct earplugs. Well, in dusty environments it's actually better to use something cheap like paper mostly because you will be "burning" a ton of earplugs during the day and let's face it I wasn't in great shape regarding my finances, so every penny counted. Later on I would change jobs and actually buy decent earplugs so I could work nearby gas turbines.

Anyway long story short, use proper hearing protection because depending on the exposure you might actually lose your hearing without noticing it. As for tinnitus, besides the usual damage done by not using hearing protection, it can be genetic. My dad had tinnitus due to his exposure to power tools, but I know people who have it since birth.

Some last thoughts, I think younglings should be educated regarding hearing protection. I mean youth will be youth, but I'm pretty sure they don't want to lose their hearing in the long run.

Best regards.

Much appreciated! I'm sure those details might help someone in the future.