How good are the Sony APM speakers ?

not very good...even then.

Sony made two speakers for the Esprit line which used APM drivers in the early eighties. One was a large rectangular monolith which was a four way design I think. The second model was a two way design also very large but with rounded sides. They cost $12,000 and $8,000 respectivly. They sounded good especially the two way. Other speakers I had listened to at the time were the Hill Plasmatronics, ESS Transar, and the original 801's. The Hills were $10,000 and most other exceptional speakers at that time were less. This APM is an example of trickle down technology, sounding great in the Esprit but leaving much to be desired in their mid-fi brethern. APM drivers are also hard to repair because of their unusual surrounds and multiple voice coils.

thanks for the responses so far

There are so many APM designs that it is hard to generalize. The ES line from SONY had a very controlled, detailed, unforgiving sound. The lower range APMs could be a bit too harsh and boxy.

On the other hand, the 2-way APM-22ES which was bottom of the ES line has a refined, detailed quality that I admire. And wonderfully musical, convincing bass. Their build quality is first rate.

The APM-615 is 3-way. I am listening to a pair now. The brass is most convincing. But the bass is a little boomy and the high end is very ordinary sounding. BUT they can play amazingly loud!

My strong suspicion is that Sony chose to under-damp the cabinets to get more bass volume. If one recalked all the inside seams and added foam to the back panel and then stuffed then full of cotton-poly fluff, I bet they would sound much much better. Perhaps even gaining the control and subtlety in the ES line. Also, I am tempted to try a diffusion ring around the tweeter. Because the 615 has a lot of promise and is basically a very good idea but the details are implemented crudely.