Closed box

[hjames]

We looked in the hole and seen that someone had plugged the other side of the port. This was the difference because after we unplugged the port they sounded identical.

Because of this and how that pair sounded I would never buy a closed system. IMO a ported system sounds much better especially in the low end. Does this make sense to anyone?

Makes sense - but neither the L100 nor the 4311s were designed as a closed box - they were supposed to be ported. Closing the port changed the working parameters. I think something else would have needed to change to make the L100 drivers work in a "closed box" system. Maybe a larger box would be needed, maybe a different woofer, but something in the design would have to change.

[Zilch]

Does this make sense to anyone?

It's a matter of taste, James.

The bass in L100s is artificial, contrived. It does not reproduce the actual performance.

Impressive, yes, but fake, and intentionally so.

That's not true of all ported systems, of course, but it's well acknowledged that a properly designed closed-box system can produce a more "natural" bass response.

The accuracy of bass in L100 may be much improved by closing the port:

http://audioheritage.org/vbulletin/s...841#post122841

[Thom]

I think the L100 was designed to be a bookshelf speaker that sounded just like a big JBL if you were down the hallway. It didn't of course because the 075 made most tape decks unlistenable a trait not shared with the LE20.

[duaneage]

Does this make sense to anyone?

The transient response of the best ported system will be inferior to a critically damped or optimally damped sealed box. This would be Qtc in the range of .5 to .707 and even the QB3 alignments don't have as good a transient response compared to sealed.

The issue really is a combination of the sharp rolloff that ported boxes have combined with poor delay curves on the driver. The sharp rolloff means the ported system actually cuts off the last part of a decay more than a sealed system does. A sealed box is a close to a snare drum (or any percussion instrument) as your going to get.

The delay curves are a result of driver loading by the port and can get very wild near the box tuning frequency or cutoff. The driver has different amounts of excursion caused by the port damping the driver's movement. Below the tuning frequency the driver begins to excurse a lot more. The port in effect dynamically changes the damping effect of the box whereas a sealed system has a constant value for box compliance with predicable results.

On a more practical note sealed boxes are easy to get right and vented boxes involve a lot of compromise, design, testing and variables. It's not hard to make a proper sealed box sound good, and it's also easy to make a vented box sound bad.

Most of my builds have been vented because that's what everone associates with great big sound. But my best results were with sealed and sealed bandpass systems because I was able to tune them easier and focus more on the rest of the system.

Just my .02, no refunds available