I have four complete 20 year old Yamaha AST-1 Systems
, each comprises an AST-A10
amp and 2x AST-S1
speakers; the nominal system/speaker frequency response is 28 Hz to 20 kHz. This is really a three piece active speaker
system: The AST-S10 amp section can be switched to 'FLAT' for use with a conventional speaker, or 'custom equalized' for a the AST-S1 speakers, but the AST-S1 speakers cannot be used with a conventional
In the 1980s, US consumers associated deep bass with large cabinets, so the AST-1 System's 8"x12"x9" speakers did not gain much acceptance [plus the MSRP was around US$1450], and I mostly saw them remaindered
I use mine as the L/C/R on two systems. Easy placement for L/C/R does not however equate to ideal bass response, and I have to add a conventional sub to each system. Yamaha gave up using the active servo technology to build compact full range speakers, but continues to use it for their sub woofer line today.
What looks like a conventional front port is the 'air woofer' associated with the speaker's Helmholtz Resonator design; I can feel air puffs from soundtrack explosions six or seven feet in front of the port.
After Yamaha lost a name ownership lawsuit, they renamed everything from AST
echnology' to YST
echnology' so creating alternate names: YST-1 System
amp, and YST-S1
speaker . . . plus lots of confusion!