Hi Thor; I use a SE EAR 859 which is 9 watts se and Theatre Pi4's. The sound is spacious, deep and quick, seamless through the midrange and very articulate. It images well in a smallish room and plays small jazz combo's particullarly well. At no time have I noticed any strain from the amp, even when using them outside on the deck. I use Bruce Cockburns album Whole Night Sky as a reference and his voice sounds natural and positioned correctly on the soundstage, the bass is very organic and acoustic bass runs up and down the scale maintain accuracy without emphasizing one note over another. The body of the stand up bass sounds woody and musical; pianos have a nice percussive effect that resonates the same as a real piano sounds and female voices are smooth and liquid. They have an ease of presentation that is non-fatiquing over lengthy listening sessions. I use a pair of Altec Valencias and A7's also and the 4's while having their own unique sound compete equally with the much more expensive Altecs. I consider the 4's to be a great bargain for SE amp fans such as myself. Hope this helps, J.R.