[mvw2]

Well, back when I owned the ER4S, I felt it rolled off below 60Hz.  It had a tough time trying to reproduce notes lower than this.  I could get it to 40Hz with some EQing but notes below that wasn't doable.  I found that the driver noticeably bottomed out when trying to push lower notes with any meaningful output.  It took a lot of EQing to extend the response and the lack of SPL meant usable listening levels were moderately reduced.  The top end also noticeably dropped off, again requiring bumping of the EQ to help extend the response.  It's not a "this has no top end" kind of thing, but the extension wasn't "limitless" like some other earphones like the CK10, Triple.Fi 10, or RE-252 where there really is no discernible end to the extension.  The ER4S did cover the spectrum well though.  It offers enough on both ends to not feel entirely lacking.  It had enough up top to not feel like you're missing anything.  It had enough midbass and high bass to produce a full presence.  It did lack the visceral on the bottom end, because 20Hz to 40Hz really is needed to develop that.  The RE-252 offers more on the bottom, although it does require a good seal to do so which is harder to get than the very easy to fit ER4S.
 
I never did say the ER4S was less neutral.  I feel it's a tonally well balanced earphone.  It's simply a matter of frequency response range.  I have yet to use a single BA earphone that offers enough breadth to fully cover the entire audible spectrum competently.  I always seems to take two BA drivers to do so.  This isn't to say that a single BA can't do ok.  Really, earphones like Ety's ER4S or Sleek's SA6 work very well and better so with the addition of a touch of EQing at the ends.  Dynamics seem to be more able overall.  Ortofon's moving armature e-Q7 does wonderfully for covering the spectrum using a single hybrid driver.  However for BAs, it always seems to take two.  The CK90Pro is a great example at covering the spectrum, 30Hz to 16kHz ruler flat, but it's two drivers.  This isn't to say that multi-driver earphones are absolute winners.  Even dual and triple BA driver earphones don't necessarily cover the spectrum fully.  The SE530 is a good example.  It has a dual low frequency unit but still rolls off way early.  it can hardly produce a 40Hz tone with a heap of EQ to save its life, and the note quality is terrible once you get the sensitivity up.  The Triple.Fi 10 rolls off a little right on the bottom end despite being a 3 driver device running a dual bass unit.  The Custom 3 rolls off on the top end despite being a dual driver system.  It still comes down to implementation and not just the number of drivers.  (Retracted, see post #22) The crossovers of these multi-driver units also create a side issue, delay.  This really only pertains to video where you want the audio and video to be well synced.  Some of these multi-driver earphones have a short delay through the circuitry that offsets the sound around 100ms, something that may influence people's decision if the earphone will be used for a lot of movie watching (some video software allows time delay changes to fix this, if you're using a PC).  Phase issues and coherency between drivers across the crossover ranges aren't always ideal either which can compromise the overall presentation to a degree.  Some of the multi-driver earphones are seemless, some not so seemless, although the effect is really only a small frequency range which in turn only pops up with certain songs, instruments, etc. that use that frequency range.  The crossover points can also be chosen to move this outside of sensitive areas.  Passive crossovers are always a compromise.

 

[Pianist]

Quote:

The crossovers of these multi-driver units also create a side issue, delay.  This really only pertains to video where you want the audio and video to be well synced.  Some of these multi-driver earphones have a short delay through the circuitry that offsets the sound around 100ms, something that may influence people's decision if the earphone will be used for a lot of movie watching (some video software allows time delay changes to fix this, if you're using a PC).

 

What? Are you serious? Where did you read this?

 

[Mad Max]

Yes, quite.
 
Citations needed, I've noticed nothing wrong with TF10's sound like you mention.

 

[mvw2]

Quote:

The crossovers of these multi-driver units also create a side issue, delay.  This really only pertains to video where you want the audio and video to be well synced.  Some of these multi-driver earphones have a short delay through the circuitry that offsets the sound around 100ms, something that may influence people's decision if the earphone will be used for a lot of movie watching (some video software allows time delay changes to fix this, if you're using a PC).

 
Quote:

 

What? Are you serious? Where did you read this?

 
Retracted: See post #22.

Read?  No.  This is first hand experience when using the earphones in conjunction with video and software that does allow the adjustment of video delay.  For example, the UM3X and CK100 both have a noticeable amount of delay that I can tune against to get things synced again.  I can swap to other BA earphones or dynamics and not have this using the same video.  Now for pure audio, this really doesn't matter one bit.  It doesn't matter what kind of time delay there is, so it's really a mute point.  However, if you start watching video using the earphones, playing games, or use them in conjunction with any video for whatever reason, the delay will be a small factor.  Is it enough to care about really?  No, not really.  It's there.  It's noticeable if you look for it.  For casual listening and viewing, it's not a big deal.  For pure music/audio it's not a deal at all.  It simply exists.  Also it's not the same for all multi-driver BA earphones.  Many of them don't have a discernable delay, but some do.  For example the UM3X is somewhere in the neighborhood of 150ms.  This is how long I have to delay the video for to sync up the sound and image to that of what I get from a dynamic.  It's lengthy enough to notice.  Other BA earphones, it isn't.  It's also something you probably won't notice casually.  It will also depend  upon what you're actually viewing and if there's meaningful cues that could even show you the offset.  For most things, you simply won't notice.

 

[winds of change]

I'm a lucky girl, I found them like "designed" for my ears; really lucky because they're very confortable to me and in almost a year I used them a lot despite the other IEM's I've tested.
I can say now that there's a little similarity with AKG K501 sound, and they're a big improvement over my still beloved RE0; I think that a classical shape could have been lead this IEM to be best known or at least high ranked.

 

[goodvibes]

Crossovers do not delay sound like that. There can shift phase via frequency which constitues something like that but we're talking 1/2 cycle of a mid or high note and nothing even close to 100ms. With the 1st order networks commonly used in in IEMs, you don't even get this. It's like saying cable length will mess with time constants. Close to speed of light transfer stuff here. The low frequency driver will never even show phase shift as it's lowest frequencies are not filtered and will have 0 phase shift. If you have180 phase shift of a 5000hz tone (a lot and not typical for IEMs) it will have a delay of exactly .00001ms. (neglegable in absolute time perseption) The type of x-overs used in IEMs typically have far less.

 

[mvw2]

Decided to re-investigate the issue.
 
The video I was using was a drum solo of Neil Peart.  Going back through with a few of my earphones it seems the video and audio are slightly out of sync by somewhere around 175ms.  The sync issue comes across less noticeable with a number of the earphones, but some show through more blaring, and this happens to be a couple of the BA based ones, likely due to the speed and short note they offer.  The sync mismatch is more apparent with them, and they seem to act like they're out of sync versus the other earphones with a thicker, smoother note and/or less attack.  I really haven't seen it in other videos, but I also used videos without such specific cues and of course they didn't have the delay.  It was something I really only noticed wit that video, which should have been a red flag, but it was also a video that was particularly good about showing a delay in the device if that existed.  In a sense, it was expected when it was noticed, and the difference in the presentation of sound changed the perceived delay time or delay all-together for some and particularly highlighted only a few.

 

[kiteki]

Thanks mvw2 for the informative thread.
 
Do you still feel the same way about the RE252 today, after hearing more IEM's?