[theblackbird]

Hello,
 
Several years ago I bought a pair of Shure SE420's. While I'm pretty ok with them (lacking some bass imo) I'm considering replacing them with some higher end IEM's. The Westone 4's currently have most of my attention.
 
But I wonder: is the difference in sound clearly noticeable? And I know this is subjective, but let's say an untrained ear listens to the SE420's and then the Westone 4's, would one notice and prefer the latter?
 
Thank you.
 
Br,
B.

 

[NA Blur]

I think the main purpose of a custom is fit and then sound.  I have worn many universal IEMs and none of them fit perfectly.  I think the SE535 sounds great and is built really well, but the fit in my ear was very uncomfortable.  I went to the JH5, JH7, JH 10 x3 Pro, and JH11 Pro after testing the SE535.  The JH5 and JH7 were quite bassy and the crossover was an issue listening to Maroon 5.  The vocals and bass would beat together creating a bass spike that would hurt my ears.  The JH 10 x3 Pro sounded very good with just a tiny bit of bass emphasis which I appreciate.  The JH11 Pro was much more neutral and a tad quicker, but really lacked the bass I prefer.
 
After reading a few reviews of the Westone 4 I imagine it is going to sound very similar to the SE535.  Both being neutral and not exciting in the bass or treble.  I would say if you want something with a tad more bass go with the JH5 as it receives many great reviews and I imagine the demo set I was listening to was not perfect perhaps explaining the beating I hears during my testing.  Customs receive so many great reviews that I highly recommend going custom based on the fit alone, but of course due to the superior seal of a custom the sound is almost always better too.
 
Going from the SE420 to a Westone 4 is not going to be a huge leap is sound quality.  There are a few resources around that may help.
 
1.)  joker's master IEM review list
http://www.head-fi.org/t/478568/multi-iem-review-262-iems-compared-ultimate-ears-ue-900-added-10-28-12
 
2.)  Innerfidelity's IEM measurement table
http://www.innerfidelity.com/headphone-data-sheet-downloads
 
Hopefully those can help you decide, but it sounds like you want an IEM with a bigger soundstage and a tad more bass.  Try looking for reviews that include both of those characteristics and you should be able to narrow the choices down.

 

[Glow Fish]

I went from a SE425 to an SE535, and felt it was a definite upgrade.  But the SE535 is really a mid-lover's IEM.  It has a bit more thump than the SE425, but not a lot.  You may want to look at the Earsonics SM3 or the JVC FX700.  Both have more bass than the SE425.  I had the W4's briefly, but found them bass light and somewhat thin sounding.  The UM3X has more bass, but also a very flat presentation in terms of soundstage. I sold both Westone's and the SE425 as well.
 
My personal favorite IEM right now is the SE535.  It has such a lush but clear sound, I can really lose myself in the music.

 

[Brooko]

Agree with Glow Fish.  I originally had the SE420's, and then the SE425's (after Shure replaced the 420's due to the old cable issues).  Absolutely loved the 425's - but eventually sold them - mostly because I was looking for a similar sound but an improvement at both ends.  The thing that I wasn't quite satisfied with the 425's was the early roll-off (or maybe lack of impact) in both lows and highs.
 
So I went to the SE535 Ltd Ed and couldn't be much happier.  They are pricey (probably over-priced considering alternatives that are around now) - but the Ltd Ed definitely have more presence and sparkle in the top end.  Still retains the intimate Shure mid-range, and fit me fantastically.  The bass is definitely better defined and textured than the 425 - but I have to admit it's quality is better than it's quantity.  Once you get used to it though (for me) ..... perfection.
 
If you want more quantity of bass than the 420s though - you may want to look at another brand.  Sorry - can't help you much there - always been a Shure IEM sound signature fan.  It's the mids

 

[ZARIM]

The Westone 4, Sony EX1000, UE900, Heir Audio 4Ai and CK100Pro willbe noticable upgrade over SE425 with increased soundstage, better instruments separation, imaging, higher resolution soundquality.

 

[wireking1]

I recently upgraded from the Shure se420 to the UE 900 and the improvement in sound quality is pretty amazing. I have have the Shure's since 2008, so I was overdue. The sound quality in the under $400 IEM market seems to have taken a sizable leap forward the past few years.
 

 

[darkinners]

I didn't try SE420 but I do have a pair of SE425 before I upgraded to Westone 4
 
Before I bought my westone 4, I really like the sound signature of my SE425, only except
1. lack of bottom end
2. recessed trable/air
3. pushy high mid
 
 
I was seeking an upgrade to maintain the similar feel of the SE425 sound.
tried SE535, IE8, IE800, Triple-fi 10
 
 
ended up got the Westone 4, definitely a very noticeable upgrade in terms of SQ.
 
SE425 is quite brighter than Westone 4, because of the high mid peaks, even the treble in SE425  rolled off a lot.
Westone 4 sound more warm and midrangy. MUCH more defined sound, instrument separation is sublime.
The bass was a little bit egged(some bump at around 80-100Hz) but the quantity is very controlled.