What brands would you be most interested in checking out?
In the Orchard area, you have
Music Sanctuary and
E1 Personal Audio. Music Sanctuary have customs and cables galore, including the new FiR Audio IEMs that are currently exclusive to them. They also have fan favourites like 64 Audio, Custom Art, Ultimate Ears, etc. There, I'd personally recommend trying out Lime Ears and qdc's IEMs, 'cus they tend to be underrated outside of Asia, along with the brands I just mentioned. E1 also have customs by 64 Audio and Vision Ears, but they're more known for their headphone inventory. They have a selection of desktop amps, DACs and full-sized headphones.
A 5-to-10-minute walk will bring you to 313@Somerset. A level below the lobby is
ConnectIT. They carry a multitude of brands including InEar, Empire Ears, Jomo Audio, Campfire Audio, Sennheiser and many more. They probably have the best balance between IEMs and headphones of all shops in Singapore. They also have audio cables from Effect Audio. By the way, if you're interested in checking out Effect Audio's HQ and watching them make cables, their unit in Geylang also doubles as
Euphoria Audio; a dealer for Empire Ears, Vision Ears and Jomo Audio. The only problem is that they're located in a more remote part of town, so you're gonna have to travel quite a bit before you see your next audio store.
A single stop on the MRT from Somerset to the Dhoby Gaut station will bring you to Plaza Singapura. On the 4th level is
Stereo Electronics, which is more of a consumer-oriented store. But, they have a fair share of audiophile-oriented products too. They have headphones from STAX, Audeze, HIFIMAN, Sennheiser, etc. Their IEM line-up includes Unique Melody, Sony, Shure, AKG, Noble and iBasso, among others. They also have gear from iFi on display available for demo.
Then, another MRT ride will bring you to City Hall, where lies the infamous Adelphi building. The place is renowned for housing a multitude of audio stores, though they mostly cater to hi-fi. You can also find a couple record stores there if that tickles your fancy. There, you can find
Jaben SG and
AV ONE. Jaben carries a number of in-ear brands, including FitEar, Stealth Sonics (I believe) and WAVAYA, along with a collection of headphones too. Right next door is AV ONE, who carry JH Audio, Vision Ears and Ultimate Ears. Their headphone collection also include Sennheiser, Audeze, HIFIMAN and FOSTEX, among others.
Finally, going by MRT from City Hall, to Bugis, then to Rochor, will land you in Sim Lim Square; Singapore's no. 1 computer centre. On the second level (I think... I keep getting it wrong too, myself
), you'll find
Zeppelin and Co. It's unlike other audio stores in that it's both an audio store and a coffee shop, so you get to try out your high-end gear whilst sipping on a cup of fresh brew. They have STAX, Focal, Sennheiser and more for their headphone line-up. And, their in-ears include HIDITION, AAW, HUM, Empire Ears, Acoustune and EarSonics. I also believe it's currently the only place in Singapore where you can try out Empire Ears' new Valkyrie and Wraith, though I'd ask around to make sure.
Hope this helps!