Sorry, I don't know of the Audio-Technica store across from Sogo. Which Sogo? There are several on ZhongXiao E. Rd. -- the green Fuxing store, the white Zhongxiao Store, and the grey Dunhua store
FYI, AFAIK, here's a list of places that let you listen to headphones and IEMs in Taipei:
1) Music Hi-Fi, on Chongqing S. Road, near CKS Memorial MRT
2) PinCha, on Kaifeng St., between Zhonghua Rd. and Yanping Rd.
3) EarTron on Kaifeng St., between Yanping Rd and Bo Ai Rd.
4) Monster Cable, First Floor of Neo19, near Taipei 101
5) Don't know what it's called, but it's a small booth inside NOVA, the computer mall across from Shin Kong Mitsukoshi at Taipei Main Station.
They have a large selection of full-sized cans and amps on display and fewer IEMs available for listening (but they do have some rarities in Taiwan, like the Sleek Audio SA6, etc.); whichever brand, you name it, they have it (AKG, Alessandro (but no Grado for some reason), Audio-Technica, Beyerdynamic, Sennheiser, etc.) and they're all available freely for audition. They even have the HD800 hooked up to a very high end system (I forget what), but you need extra special permission to listen to it. Their amp selection is nice too, having recently become the Taiwan distributor for Schiit Audio. They also have the requisite Taiwanese brands Keces, Firestone, Kingrex, etc. High-end stuff like Weiss is also available in their special listening room.
The area of PinCha is quite small, but they pack a lot into it. I noticed they had some Woo Audio on their shelves; didn't ask if I could listen. I did, however listen to the Grado GR10 there. I'm going there for a second listen to see if I want to actually buy it, and maybe get lucky with the Westone 4 that just landed in Taiwan. On the full-sized part, I know they have AKG, Grado, and Sony available, but I haven't asked to listen. They also have a large array of head amps available from the Taiwanese brands (I'm most interested in the U2 from DA&T), as well as high end Benchmark DAC1, etc.
It feels the most pedestrian of the three stores because it only has headphones and IEMs for people to listen to; one has to goto their old place, EarZone, on Zhonghua Rd. around the corner to listen to their amps and sources. However, it is to me the most friendly of the three. They are very relaxed and let you listen to several pairs to compare against at the same time. This is where I do most of my heavy listening. I can take my time and compare between the UM3x, SE535, ER4P, IE8, etc. without feeling pressured. The PinCha owners seem okay, but they're usually very busy, so it's a cramped space. Music Hi-Fi is good too, but since I mostly listen to IEMs, I go there less, especially when they've slow getting back to me about whether or not they'll help me order Unique Melody customs.
You can imagine what it's like here. It's very consumer oriented but they do have all the Monster products available for audition, from the entire Beats line to the Turbine line. Of course, you'll also get the inflated corporate prices here too --- the Miles Davis is 16,000 NT!
Another non-audiophile oriented establishment. However, they do carry a nice selection of Audio-Technica; this is where I listened to the ATH-CKM77, the first time I listened to the AD700, the M50, and the Sennheiser HD25-1 II. They have other products there too, as well as the whole gamut of Shure products. Most of the IEMs they have available to listen are lower end though. Unfortunately, it's probably the loudest place of all, since it's inside a bustling computer mall with people competing for customers and a line of people next to them for the Shin Yeh buffet upstairs.
Hope this was helpful to all my fellow Taipei Head-Fiers.