Logitech Surround Sound Speakers Z506 (980-000430) - Reviews
Pros: gets fairly loud
Cons: audio quality.
I got these as a gift during Christmas. The rear speaker cables are 15ft which is reletivly short and most of the time the sound they produce is unnoticeable. they make a lot of static noise and the sub is easyaly overpowered. for watching youtube or a movie they are great. however if you want a cheap system for music there are way better for the price.
I have had the Z506's predecessor, the X-540 speakers for almost 6 years now. Downgraded from my old Logitech Z680. The sub of the Logitech Z-680 had a buzzing sound within a few months of use that forced me to set the bass volume to less than 10% (although it was sufficient enough for decent bass). Until now the X-540s have not shown any signs of aging or sound deterioration. This considering that the speakers have been dropped a few times as I relocated 3 times and also had my little brother's toys thrown at them occasionally causing a minor dent on one of the speaker grills, it still performs well after 6 years. No distortion, and no discernible deterioration of sound quality. At least I didn't notice it. The sub doesn't have a grill and is exposed, although it is still intact since it always faces the floor and I often keep it in enclosed spaces.
The speakers are ideal for a small size room. I never had to go over 50% volume. The bass, despite its small size is no slouch, I had to set the bass to 25% max otherwise the neighbors would come knocking. The speakers can be wall mounted easily as well.
These speakers are perfect for the price. My only gripe with it would be the cable length and the inability to replace the cables. I had to use extension cables if I wanted to set the speakers a little further away from the sub. I don't expect the best sound from these speakers and therefore don't think anyone would want to replace the cables as it might have minimal positive effect at best. But still the experience I've had with it was positively great.
I also like the fact that I can control the main volume and bass volume through the extended dock.
Definitely better than the Z506 (which is "supposedly" an improvement model). I don't like the fact that the Z506's volume controller is on the right speaker. This limits the positioning of your right speaker. Also the bass volume controller is behind the bass, which would be an inconvenience for some, especially for those placing their sub inside a cabinet or enclosed spaces. Not to mention less drivers and are priced the same or higher.
I would purchase X-540s again if I could, and would definitely recommend these to anyone interested in a budget 5.1 computer speaker system.
Pros: Easy to set-up. Amazing value. Decent power.
Cons: No hanging options. Average Sound Quality. A lot of ground noise.
This set is in no way flat, response wise, but I bought them because I wanted to be able to watch movies with decent audio quality without headphones. 
The sub is pretty decent. Too small for proper sub-bass, but bass and mid-bass are plentiful. Does tend to distort when pushed hard, and the cone on the sub is unprotected from being punctured.
Continuing on the V shaped tendencies, it does have quite a noticeable hill in the 10-12KHz area, I think just to make it sound like it has a lot of fidelity. But it isn't too harsh.
I have no idea why there's a doughnut shaped hole towards the top above the centre driver. There's absolutely no sound coming out and it's gathering a lot of dust. It's probably to fool people into thinking there's two drivers per speaker. They didn't even do that with the Z5500's so I have no idea who would be fooled into such thinking.
Apparently because it's neodymium there's no need for more than one driver per speaker.
It has pretty bad noise issues though, I'm thinking it's to do with the amp (within the sub). I stuck a ferrite bead on the power cord, looped through twice. It did halve the noise, but even when using the headphone jack on the front right speaker creates noise with head/earphones that sounds like a desert wind howling in a sandstorm.
Set-up takes about half an hour from un-boxing to up and running. Cables are reasonably long for a small theatre, probably inadvisable to extend them further, even though they're "balanced".
I wanted to hang them, but there's literally no way to hanging anything apart from the centre speaker, and even then it's bothersome.
Inputs are standard 3x1/8'' jacks plus Stereo RCA. 
I wonder if I can hijack the amp in any way....
All you gotta do is buy two RCA cables...
Cheers, and just into phono on the amp?
Sorry for the hassle, much appreciated.
Hi, how can i connect Logitech Z506 with Creative Sound Blast X-Fi 5.1 Pro USB external card? and when i tried to connect with my laptop sound is coming from two speakers only? why not all 5.1 speakers working? i need setup guide please. Thanks.