They are heavy suckers and look like my drowned SVS barrel sub. Gives you the feeling it's a top notch product. I'm a JBL fan for years. I guess no need to look at speakers anymore for a while if these work perfectly. Too bad no review on YT. Just sound demos alone you can hear how good the bass is. Mark are they 8 or 6inch woofer on the top glass part?
The 520’s have two 8 inch woofers bolted together in the bottom end of the cab . The crossover is mounted to that plate with the binding post and compaction switch Iam pretty sure there part number is 408 G . The bottom chamber is sealed when the bottom is in place the top part is I believe a double chamber vented out the top .
Most of these drivers are available on eBay for reasonable cost as all these drivers were used in various high end jbl books at one time pretty sure most are 4 ohm too . A lot of guys part the drivers out . I have enough spare drivers to rebuild two of the 520’s if I blow something but Iam telling ya you’d have to really abuse these to burn something out . If these work out for you indeed build your system around these I did and if problems do arise there most parts to be found ya got to dig but there out there .
These are the only speakers I’ve ever herd that just disappeared in a large store showroom. When I bought my second pair about 10 years back I needed a glass top and a switch to get one running and jbl put me in touch with a warehouse in New England some old guy run it I told him what I had and what I needed for the price of one crossover he sent me everything he had for them two complete crossovers two still packaged glass tops and two sets of toe spikes . As these were Danish made everything is metric.
these were primarily for the European market Germany to be exact the 520’s and smaller 420’s made it over here I’ve never seen the 580’s over here but you can find them in Europe but shipping is insane . I apologize for the long and boring response — don’t drop these on that toe bro !
