I managed a RS store in the mid seventies and the Mach I speakers came out in 1975 I believe. They replaced the discontinued Optimus 7, which was in my opinion the best speaker Radio Shack ever carried, by a long shot. I still have 4 of them in my main system, and they're outstanding.
But in my opinion RS blew it with the Mach 1. The 15" woofer was boomy and not particularly articulate, and the horn was annoying. I don't mean to disrespect any fans of the Mach 1 but I couldn't ever get them to sound good, and I worked with them for 8 hours a day!
I worked at a Radio Shack in the late 1970s for a brief period of time. I don't recall if we had the Mach One or Mach Two speakers at the time, but I do remember when we did inventory, which was monthly and done by hand and often took well into the wee hours of the night. We were allowed to pump the volume up to nearly intolerable levels, since it was a commercial area and no one around to complain. I remember well that the Mach speakers, whatever model they were, were as you describe; loud and boomy, but we actually didn't care for them. We usually ended up hooking up a set of the lesser models, I don't recall which one, but they weren't large, and preferred the sound.
I now have a set of Mach Two speakers, and I refoamed the woofers, and I honestly do not care for them. Loud and boomy, not articulate, not even pleasant to my ears. So I think I'm with you in terms of my opinion of the Mach speakers.
However, two things.
First, the OP didn't really ask if the Mach One speakers were good speaker, but whether or not they were worth $90. In terms of resale value, I'd say they do seem to sell, regardless of what some of us think about them. They have definitely achieved some sort of minor cult classic status; even if you and I do not care for them.
Second, there's a very long and detailed thread here on AK started by (as I recall) VideoLady, regarding how Mach One speakers can be redone to sound, according to her and many who have done her mods, quite nice.
So I'm not going to slam the Mach series speakers. My own opinion of them isn't really very good, but that's beside the point. The question was are they worth $90. Perhaps not to people who don't like them, but they do seem to be popular enough to sell. Best of luck to the OP; if he gets them, I hope he likes them. If he doesn't like them, at least there is a market for them. Unlike a lot of my unloved speakers, which if I tried to sell them would draw only laughs!
