2. Exactly what I want to experience.
I imagine most of the RE-400 owners are coming from fairly neutral phones so they find the 'relative' slight warmth appealing. I'm heading over here from basscamp, so I'm not sure about how I'll feel.
The fact that you are a "converted basshead" makes your advice easier to swallow
3, I'm not going to even pretend I understand completely what those graphs mean. So the damping affects the upper-mids and beyond. I'll keep your felt mod in mind though.
@modulor, @Tom22... Thank you very very much for all your help and advice. I hope to get my RE-400 in the next 2-3 weeks. I'll be back with my impressions, whether positive or otherwise. Bass quality! Here I come!
Any time - glad to help! I think the HiFiMan IEMs are an entry point for more neutral signatures for a good number of people. My first 'nice' IEM was actually the RE-ZERO, which at the time I felt was too bass-shy without a bit of EQ. If you are used to a bassier signature, you're definitely going to have to give these 1-2 weeks minimum exclusive head-time - that'd be my recommendation anyway to get adjusted to the new signature. I'd be interested to hear your initial impression, then a 2 week update.
I wouldn't exclusively call my former self a 'basshead' but bass was definitely a higher priority and something I always worried about lacking in neutral signatures. I don't feel this is the case anymore, but it definitely took trying out a few different IEMs and headphones. RE-400 is a great place to start exploring IMO - very technically capable, very transparent and great extension on both ends of the spectrum. Not necessarily exciting in that it gets your heart pumping, but exciting in that you can hear more details in a very clean manner. My revelation came when I first heard the HE-500 - I was shocked because while it's quite neutral with tight/quick decaying bass, that bass is definitely present and the large drives can move some serious air. You can feel the bass without resonance (only textured by itself I guess is one way to say it) and it goes down to 20Hz audibly. Impressive bass presentation both in terms of quantity and quality, but I still have a soft spot for some powerful, resonating bass boom...it's all relative and depends on the listener, content and situation I suppose.
I'll try to give a quick explication of that first graph I posted - on both charts, the horizontal measurement is the frequency (from 20Hz up to 20kHz in the first chart, and deviations from the stock measurement in the second) and the vertical is dB level (loudness/sound intensity). Basically, the first chat is the frequency response curve with total dB level measured at each frequency, and the effects that the different variables being tested. The second shows a little more detail because of finer increments - the reference stock measurement is equated to 0dB, and the others show the deviations above and below it depending on the different variables being tested. You can more easily see the differences here - adding a piece of felt/microfiber cloth/handkerchief drops the 6k region from stock by about 4dB, while removing the filter and foam and leaving an empty nozzle will raise that same area from stock by about 6dB. Everything below 1k is relatively unaffected. Adding more acoustic damping will lower the treble, which in turn elevates the mids and bass relatively. Think of it as a physical EQ tuning.