The web's headquarters for discussing high-end personal audio and headphones, Head-Fi, has released an in-depth review of Heir Audio’s 6 A CIEMs. This review has positive analyzed 6 A from various aspects covering designs, craftsmanship and of course sound quality. In conclusion, 6 A is claimed as “Heir Audio has another winner on their hands. Despite a rather unorthodox driver configuration, or perhaps because of it, the 6.A performs like a full on flagship model. Despite living in the shadow of its older brother the 8.A with its higher driver count and larger price tag, the 6.A is absolutely a top tier IEM.”

For details, please refer to the link of the review:http://www.head-fi.org/products/heir-audio-6-a-custom-iem/reviews