I received a pair of 1964 audio A6t's as a gift from an awesome friend and I have to explain how vast a territory these IEM's cover. They are incredibly linear in frequency response which is perfect as I am an AV Technician at a conference center and a musician. So I actually use them for everything from listening to recordings, to editing audio, to checking mixes, and to using them live while performing. I have yet to hear anything close to these. I previously used an older pair of Shure 500's, pre SE Series, and they sounded great but my ears were always tired afterward and I always felt drained. I believe that is because there was no pressure equalizing system which the 64's have and it works incredibly well. There is no extra pressure on my ear drums whatsoever and the ones I have cancel out 20db so I can sit at a piano, or play guitar and only hear them a little acoustically speaking. Because of this I can hear everything I need at a MUCH lower volume in my ears. My ears are more than happy and I geek out every time I use them. The only drawback is the difficulty getting them in and out of my ears but it just takes practice like any other fitted earpiece. That being said, once they are in my ears I could wear them all day long. If you gig long in loud situations or you are just doing a 15 minute set, and whether you're a pro on tour or local musician performing in a small club or playing for church, THESE ARE YOUR IEM'S! They. Are. Worth. Every. Penny. Sell whatever you need to, donate as much plasma as it takes. I am seriously considering buying a pair of A2's or A3's as backup and for personal listening. They sound so good, they are comfortable, and they look great while doing. 1964 Audio, you are not a business, you are a ministry to musicians, sound engineers, producers, and audiophiles. @64audio read more