This is incorrect, rear vents on iems is a significant tuning choice. Yes, There is a resistance element glued to the rear of the driver, but sealing Vs leaking the housing has a dramatic effect. Rear loading a driver and venting the rear cavity are entirely different things

Ahh yes you are new here, welcome 😂 it only gets worse lol

Yes of course the changes would show up in FR but if they’re disproportional and non linear depending on frequency then you in fact cannot extrapolate all extra information from FR alone, you’d need additional information to find the unknown variables. Without a valid min phase assumption there’s too many unknowns to solve. 20-50hz is for sure in most people’s audible spectrum, as is alot of the hf content susceptible to it. Again, not saying this is inherently a bad thing, but it is true. Please see my other comments below for more discussion

Oh not at all, it’s all about learning and sharing. I mean I would say a 5ms delay in the low frequencies in those plots is pretty significant… and then a 2ms deviation in the high frequency as well on the lcd2. I also put a lot more time into listening than graphs myself, but they can be useful. The logical fallacy here is just that if they’re going to say it’s min phase and that, due to this, all information about transients and speed etc blah blah is all wrapped up in the fr. Well that’s just not true, a 4ms group delay in audio is not insignificant and could definitely lead a trained/experienced listener to hear a difference. So while in the grand scheme it doesn’t really matter, sometimes I put my neck on the Reddit echo chamber chopping block and say something 😂

To simplify it a bit, I’ll explain an example vs the actual concept as it gets kinda messy. A consequence of being minimum phase is that: Amplitude and decay time are proportionate. / louder sounds take longer to decay than quieter sounds, and the relationship between these two is constant. Areas where a system is NOT minimum phase would have that relationship breakdown such that either the proportion changes (got quieter /louder and the decay doesn’t scale linearly or equally to other frequency bands). This has consequences - though not necessarily negative. It just causes some issues in the common argument that “frequency response is everything, it tells all the info you need because headphones are minimum phase”. And while admitting it tells you a lot, I can’t help but be a little bit of a stickler just because it annoys me when people echo what they read elsewhere in other comments without knowing what it means. But now you know! https://www.reddit.com/r/headphones/wiki/resourcesindex/where-to-find-headphone-measurements/minimumphase-csd-ir/ here is another fairly short read I found from a while ago that discusses it a bit more without getting tooooo deep In the weeds

Interesting fellow oratory, no disrespecting the legend, but I also have a graduate degree in acoustics, and headphones are my full time work. I’ve measured many many headphones and in fact found, as I noted, that many headphones aren’t minimum phase “for their entire bandwidth” and I highly doubt he’ll disagree with that statement. It’s common knowledge in the headphone industry. There’s even some good plots of it floating around this sub , if I recall specifically calling out the LCD2, focal (forget which one), m50s, and hd600s. If you don’t believe me dig around and you’ll find them. - not that that in any way makes them bad headphones, again, I just get frustrated when people just echo other comments they read when they don’t know what it means/it isn’t completely true

Most headphones behave as a minimum phase system… for some of their response range, but many popular headphones (audeze, hifiman, sennheiser etc) have large portions of nonlinear and non- minimum phase response within their operating range. It just bugs me that everyone screams minimum phase and few of them actually understand what it means and /or if it’s even true.

Just to add in, literally everyone on this sub screams minimum phase this, minimum phase that….in theory… sure! In reality, a very small number of headphones actually behave this way, most of the favorite headphones in this sub and totl cans do NOT behave as minimum phase systems for their FULL bandwidth.

That is all . That’s the only point I wanted to make. Headphones aren’t often TRUELY minimum phase. The end. Let the downvotes begin.

• a headphone designer who has measured many many headphones.