Summary: Very powerful for its compact size. I was quite surprised. I was worried about the chirping thing but mine doesn't do that. It definitely does power down too often when you are watching TV without much bass in it, though. Wish it didn't do that. That's my only (small) complaint. I've had it for 2 1/2 years and I still love it.
Summary: Kudos to Amazon for their customer service but at the same time it shouldn't have happened. The first sub I received was clearly a repackaged return (still had the old shipping label) and was blown with a rattle to it. A quick call to Amazon and they had a new one shipped overnight to me and dispatched UPS to pick up the bad one. Once that issue was resolved, this thing is rock solid and fills my room with beautiful deep sounds.
Summary: I bought one of these for a living room/home theater setup. I got it to replace a JBL PSWD112 Powered Subwoofer that I bought in 1999, replaced under warranty in 2000, and has been thumping along ever since. The old unit started to crackle so I thought I'd upgrade all of my speakers.
Excerpt: Bought this monster back in May of 2007, and ever since have been enjoying movies and music like they really should be heard - and felt :) I also have JBL's Studio L880 towers, which produce pretty strong bass, but the L8400P goes beyond them, with even deeper reproduction, and more "oomph". The only thing I would have preferred in this sub would be a different design for the feet. But that's very minor, and a personal preference.
Fantastic bass, but price will increase about 50% before its possible to use it in Europe.
christer roth, Amazon
18 October 2013
Summary: The bass is fantastic. Unfortunately, the subwoofer is built for 120 V/ 60 Hz 700 W. It means that in for example Europe you have to buy a very big, 12,4 kg and expensive transformer to use it. Maybe that should be mentioned in the adverticement.
Excerpt: Bought in Lima, Perú, this incredible subwoofer has delivered thousands of hours of joy, no matter you use it for music or films. Although I purchased a 110 V model, with a good transformer it works finely and matches perfectly a Denon AVR 4520. Highly recommended.
Summary: Time for an updated review on this product since the others here are a few years old. Picked this up in August 2013 when my ancient JBL PSW120 finally died after 15 years of service. And after a month of use, I can say I am happy. I did a lot of research on subs and saw that internet direct sellers like SVS, Bic America, and Hsu were now all the rage - along with well-known Velodyne. But I wanted to stay with JBL after my past positive experience.