A 30 watt amp, 40 into 4 ohms, may not be enough power for some of the speakers mentioned above. The one with which I am most familiar, the Harbeth Compact 7, will sound nice with a low power amp with the kind of music you listen to, but you won't be getting as much out of the speaker as it is capable of delivering. Although it is my favorite speaker, and Seandt's advice is good, as usual, the Compact 7 does very well at imaging and soundstaging, its primary strengths are tonal accuracy and midrange clarity, especially in vocals.
The Compact 7 was actually designed in 1994 (later changes were all cosmetic), and was not derived from a BBC design, except to the extent that the designer's work is informed by the BBC tradition. It replaced the earlier Harbeth Compact, which was also designed by Harbeth md Alan Shaw, for home use. Harbeth did make a BBC LS3/5a and a BBC LS5/12a, and currently offers a range of Monitor speakers that are "drop-in" replacements for BBC monitors, but the Compact 7 isn't one of them.
The Compact 7 is a fairly large box. Most speakers that are considered good for imaging are narrower, like the Audio Physic speakers Seandt also mentions. One Harbeth speaker that is absolutely uncanny in its imaging ability is the HL-P3ES, about the size of a shoebox, made to replace the LS3/5a. I had a pair of the predecessor HL-P3 (no ES), and properly set up, I could almost walk up to one of them without having a centered vocalist or soloist move from the middle. Also exceptional, as is the Compact 7, at producing the illusion of a solid three dimensional performer in your listening room. With the P3's, you would need to add a very good subwoofer, and probably a more powerful amp.
Paul
