Preface: I generally don't like to write reviews about things I know little about, but I guess you have to start somewhere. Also please be aware one of these speakers has damage to the rear face of the enclosure. Recently, I picked up a pair of S-500X speakers from ebay for $60 - I paid more for the shipping than the speakers. This appears to have been a great bargain, as the only other auction has the speakers alone priced at around $125 + shipping. Unfortunately, they were not packaged properly for shipment and one arrived damage due to what was either two separate hits, or one very nasty big fall. I got my money back without a problem, so these speakers are essentially free now. In my uneducated, unqualified opinion it has so far had minimal impact on sound quality. To me the speakers are still serviceable and function well for listening; I may not attempt a repair at all for fear of altering the sound of the damaged speaker. It's possible it is creating resonance issues with certain frequencies but again I don't have proper measuring equipment or anything. The speakers are kinda tall, but still what I would consider bookshelf size. Height: 14 inches Width: 8 and 3/4 inches Depth: a tad over 8 inches Specs on these speakers are hard to find. But I did find a scan from a manual. I really liked that they were 91dB because more efficiency is always better in my book. They seemed well matched for my Pioneer SX-636, being 30W nominal power. I also liked that they had front ports (well the messed up one now has a rear port too lol) They actually are very nice looking speakers if 80s aesthetic is your thing They're a big larger in person than I was expecting, but they still sit rather well on my computer desk on either side of my monitor. I have them setup as best I can and the stereo image seems to be pretty decent for nearfield listening. They are angled inward, and from inner edge to inner edge are sitting around 32 inches apart. My listening position is roughly 32 - 34 inches from the speakers. Sometimes it works well to scoot back a few feet, other times the sitting at desk position is well enough - I think this may be personal taste for me. The stereo image itself seems fine. I can clearly detect panned instruments, and can also detect centered content, although it isn't coming from behind the speakers due to the limitations of my listening room, it still sounds nice. The tweets are roughly at ear level, but I think if I raised them a few inches the sound might be slightly better. The low end is kind of "meh" in my opinion. Don't get me wrong, if you crank the volume up on a good song, and crank the bass as well, you can see the ports moving air, as well as feel it if you put your hand up close. At low / moderate listening levels I don't think they do much though. They can definitely provide some bass smaller bookshelves may not, and a little bit of punch, but overall I think they don't hit very well. Probably realistically useless below 60hz in my conservative estimate. You can get a little more bass out of them on my SX-636 by engaging Loudness mode, and also increasing bass on the tone controls. It doesn't get very bad / distorted that I can detect but I didn't do extended testing because I'm afraid of breaking stuff on accident. As mentioned before there may be some resonance issues / frequency peaks, however a little DSP has been able to correct it for me when playing audio off the computer. I don't know if the damage to the rear of the one speaker has something to do with this but it does seem "louder" than the other in subjective L/R panning tests. I haven't found anything too objectionable about the tweets. They appear to do their job well, and I haven't had an overly harsh / painful experiences with them. I usually don't have to touch the tone controls unless a particular album was mastered with excessive high frequencies. More often than not I move the Trebel notch a tick or two up rather than down, from flat. That may be the 636 though as I have done with with other speakers too. You could certainly do worse for a pair of bookshelf speakers I think, I know a smaller pair I have been using from an old Sears LXI mini system (5.25" woofer, smaller box) can't thump as low as these do and still sound natural. Not sure what else to write about these speakers, only that I wish they didn't arrive beat up like they were. They appear to be very suitable for all genre of music, although most of my testing was conducted with Electronic and Hip-Hop tracks for vinyl, and some Jazz & Rock style music added via the computer. My overall impression is that these were probably decent speakers for their time. I don't know their original cost, or what spectrum of the consumer market they were aimed at. But I think these speakers will do just fine with a 8" or 10" subwoofer added to reinforce the low end and then pick up the slack of sub bass frequencies. Crossing over at 80Hz will probably work well for a starting point. I don't know how much they are realistically worth. I paid $22 and I think I got a bargain deal from a naive seller to be honest. Shipping was nearly $40 but they weren't packed well, which suggests someone who has not dealt with a lot of audio products or how to ship them. I've seen these speakers listed for over $100 but personally I think they are probably asking too much. $50 - $60 for these is a good deal, and then if you have to pay a little extra on the shipping the total might come out to $100. That seems more reasonable. I could be way off but I'd feel satisfied if my total purchase cost for these off the Internet was $100 or less.