I had a pair of 510As recently and I thought they were pretty nice. Not the most revealing but well balanced and powerful sounding, with a large soundstage. I had a pair of 508s many years ago. I think they sounded very similar, with the larger 510 having deeper bass, of course. I agree that they need some good power to get going.
They don't sound anything like the old altec horn systems, of course.
If you like their big sound I don't know of much under $1500 used that would improve on them. Possibly Von Schweikert VR2s or Thiel 3.6s, for $1200-1700 used would be the next step up giving you the image size and power of the 510s with better resolution.
They don't sound anything like the old altec horn systems, of course.
If you like their big sound I don't know of much under $1500 used that would improve on them. Possibly Von Schweikert VR2s or Thiel 3.6s, for $1200-1700 used would be the next step up giving you the image size and power of the 510s with better resolution.