24/11/2017
Purchased (Black Friday)
23/12/2019:
After two years since I bought them for 100 euros, they are very decent and quite powerful speakers; they haven't shown me any problems (so far). The power supply is filtered by an APC, and the green input of the speaker is also filtered for any interference. The potentiometer has negligible interference. After two years of use, I can say that they have settled as speakers; of course, their bass is quite strong even at the first level (where it makes the click), resulting in it becoming annoying. I don't know much about sound, but I suspect that with a sound card better than the one on your motherboard, you will find the perfect balance. I am more than satisfied. Highs, mids, lows—all very nice, rich sound without distortions. THX knew who to collaborate with and put their signature on it. Well done! One negative thing that I’m sure happened to me is that when I lower the volume too much, the sound only comes from the speaker that does NOT have the potentiometers and the switch, but as soon as I raise the volume a bit, everything is fine.
6/4/2020:
After a bit of searching on the internet, I read that the RCA => 3.5mm jack cable is slightly better. Switching to a simple jack with (two obviously) male RCA plugs changed the sound for the better, and the interference was almost eliminated! I’m approaching 3 years and I am extremely satisfied!
Searching today 18/4/2020, I found something I had noticed for a while. The speaker with one button and two potentiometers has a scratching noise, and generally, when I turn up the volume (this sound does not occur on the bass potentiometer) or keep it steady for a while and turn left or right. Looking a bit further into the issue, I read that the Z623 often has this problem with the volume control potentiometer. I solved (probably temporarily, long-term will tell) my problem simply by removing the plastic cover for the potentiometer and sprayed a little WD-40 inside, and the scratching completely disappeared; it’s even better to spray with contact cleaner. This happens because the potentiometer is analog and not digital, so it collects dust, hence the scratching/interference. This is what I read, and this is what I pass on to you. You can look into it yourself. I, however, still remain satisfied at 101%!
21/11/2020:
Three years now, and everything is as it was on the first day; crystal clear sound just like the first moment. Everything flows excellently. I am still fully satisfied with this system. If you find them for 90-100 euros (new, of course), buy them.
16/06/21:
Everything perfect as on the first day, whether highs, mids, or lows!
24/01/22
Everything excellent.
24/09/23
We continue steadily quality-wise, no problems!
20/11/23
One potentiometer (the volume one) broke, any repair/replacement is futile. Six years in my hands, and they have gone through all stages: metal music, Pontian music, and ample house music in all its glory. I bought them for 100€; did they deserve the money? OF COURSE, an amazing system. What I can say is that it has very strong bass. I am seriously considering buying them again... Very beautiful and warm sound; over time, they settled more and more. I am completely satisfied!