TL;DR - balance the sub with the monitors, use the -10dBV setting on your LSR monitors if that's what you're using (as stated in the manual), and don't hesitate to use the -10dBV setting on the sub to get proper gain staging even if you're using "professional equipment." If you just dime everything, it won't be properly balanced and won't sound good. Balance out the system and use proper gain staging, and the sub is fantastic! Hugely powerful. Would probably take the paint off my walls if I cranked it too much. However, even with the imposing power, it's never boomy or distorted. The 80 Hz setting is recommended for use with the LSR305, LSR308 or any studio monitors. The External setting allows use of an outboard crossover.

It took me a few minutes to dial in the JBL, but once I figured that out it sounds smooth and complimented my setup perfectly. I'm not sure why anyone in a studio setting would want to use anything but the 80hz crossover. It had PLENTY of power, in fact, it's set to about 40 percent power to balance out with my studio monitors. Folks that say it doesn't have enough power need to turn down the gain of their monitors. A TRS connection into one side only yielded the weakest output—same with XLR. Going to an unbalanced mono guitar cable into one side gave me much better output but I suspected there was better. The -10dBV/+4 dBu sensitivity switch ensures compatibility with a broad range of signal sources, allowing you to connect the LSR310S to high-output professional equipment without any danger of input overload.Now, the bass in cd audio is incredibly amazing and you can easily and clearly hear all the high frequency too. I have the 305Ps placed near two of my room's corners; and the sub sits, a little in front of the 305Ps, in almost the room's horizontal center. I moved it nearer to a side wall bc when it's placed in the horizontal center the bass from one side of the room perfectly meets bass from the other side and the bass cancels itself out. This was quite evident, then moved this sub over a little… and bass sounds fantastic now. This change of mind return policy is in addition to, and does not affect your rights under the Australian Consumer Law including any rights you may have in respect of faulty items.

JBL Transducers are legendary for their performance. The custom-designed driver in the LSR310S exemplifies JBL engineering prowess, delivering deep low frequency response into the 20 Hz region, and 113 dB peak output, for long periods at full rated power with no risk of failure. Here's what JBL have to say about this Sub Woofer The downward-facing driver ("Low Frequency Transducer") has a diameter of 10 inches, which corresponds to about 250 millimeters, and has a very soft surround and a fairly large, maximum deflection of almost two centimeters (3/4-inch). By the way, "transducer" means structure-borne sound generator and is a clear indication that the loudspeaker radiating downwards should reproduce the low frequency components that are particularly popular in surround environments and that are barely audible but physically perceptible. Finally, I used an unbalanced guitar cable in one channel only. Boom! There it was! My studio is in the middle of electrical interference hell (aka the Silicon Valley) so I used a balanced cable from the MC3 to the JBL but terminated it with a 1/4TRS-F to TS-M stereo to mono converter (Hosa GPP-290). Now I had a balanced line with a mono plug. Hey, it works and is quiet.Create the full-range sound you need out of your studio monitors with the JBL LSR310S active subwoofer. The rich and full low end you'll get from the 200-watt Class D power amp and 10" woofer will make it easier than ever to create amazing sounding mixes. When you activate the XLF Extended Low Frequency Setting, you'll get a club-like response that will help you tailor your bass volumes and frequencies to perfection. The JBL LSR310S powered subwoofer delivers deep bass down to 27Hz to round out the sound of your studio. Ported design means more accuracy at low volume levels Definitely not made to sound good in any condition. Will require a half decent room to sound the way it should. It definitely didn't sound bad to start without a good room but it was a little separated. This sub completely changes music; I'm using it with two JBL 3 Series MkII 305P speakers supported on stands; the 305Ps connected to this sub and then the sub is connected to a "SSL 2" interface; the interface's usb cable connected to my CPU. To sum up, I finally got the promised output and it balanced nicely with my monitors. I also found some shelves that now rattle because of the extra bass (easily fixed). No adjustable crossover, so if you want to crossover at anything other than 80hz, you'll have to use an external crossover.... DON'T SKIMP.

JBL Transducers are legendary for their performance. The custom-designed driver in the LSR310S exemplifies JBL engineering prowess, delivering deep low frequency response into the 20 Hz region, and 113 dB peak output, for long periods at full rated power with no risk of failure. Would you be interested in reading about Musical Review: A Little Night Music Review as well? There's a lot of great information to be found in this article.The audio quality wasn't excellent, for me, until I ended up with the sub and both 305Ps' Input Sensitivity set at +4dBu, sub crossover set at 80Hz, each 305P's EQ Boundary and HF Trim both of them set at 0, both 305P volume knob at 9, and sub volume at max, interface volume around 1:00. The whole idea of a studio sub is not to blow you away (which this can certainly do) but rather to compliment (extend the frequency range of) the monitors. It does this very well. If you don't use this balance, your mixes will not be accurate may result in them being low-frequency deprived. The JBL instructions state that when you do this, go into one side, either L or R but not both. Do not believe this. I bought the 5" JBL powered reference monitors, and I am very happy with them. I like to do most of my editing at lower volume levels. And you're only going to get so much response from a 5 inch 'woofer', especially at lower volumes. I was going to get a larger set of studio monitors, but space in my studio is getting slim. Sales suggested this. It's not a 'wow, what a difference', and that was not my expectation. It permits me to hear the lower ends in my mix that were present but not too audible with the smaller reference monitors.