Quote Originally Posted by Calestus View Post
No idea, I bought it this way. Most of my speaker knowledge comes from my car audio days. On ported enclosures, the port is almost always in close proximity to the driver due to size constraints.
In most speakers in car audio with a port, the driver is a 10+ inch woofer, by comparison, the port is rather small.

On the L5, the port looks to be about half the diameter of the 708 driver. Its somewhat behind the driver as well. This as I have read, can cause the woofer to act more like a free air woofer in a respect - the box does not damp the woofers excursion as much, and sub bass will overexert the woofer. The reason I am lead to believe this is that both of my 708 woofers had spider damage where they separate from the cone due to over exertion and degradation of the adhesive used.

That said... my woofers were still moving, and not cooked. Had I kept listening they would have been. But I stopped and took a step back, and called a pro.

While my diagnosis of torn seam between spider and cone was correct, there was something I didn't know about:

When a speaker bottoms out, the voice coil former will hit against the backing inside the basket and damage the former. This can cause coil material to unravel from the former, contacting the inside of the basket, causing additional rubbing beyond the cone and spider friction. This was what was going on in mine. The repair person dissected the original driver, inspected it, and rebuilt it with the original cone. Its impossible to tell which one he repaired, and even he had trouble identifying which one it is.

In my limited experience, and based on posts and videos I have seen, it would seem that the 708 suffers an early death if neglected, but can be brought back from the brink of certain death if one has the patience and means to go about it. It also helps to use professional repair people with real world experience working with JBL and other high end and vintage drivers.