I found this EQ to be dull and lifeless. Unless the bandwidth was extremely to minimum or maximum width, there was little discernable difference in octave spread. I guess I should have not expected much more from a product in this price range. Presonus used to make great products - MP20 Preamp for example. Maybe, like so many other 'cheap' products coming from Asia, Presonus has chosen cost-effectiveness over good quality.

My PreSonus EQ arrived with the bottom of the unit scratched up a bit despite the fact that I paid for a new unit. I hooked it up according to the directions in the manual, and also tried some other configurations. The unit failed to work at all. No sound would pass through it-- with or without the bypass. There is no excuse for this kind of shoddy quality control. Even for a Chinese product.

I spent a lot of time on the internet reading and giving reviews of equiptment, etc. My last adventure was for a personal audio station to sit next to my recliner. I needed a headphone amp. I read all I could find on the internet. Then auditioned the Grado RA1 and the Creek OBH 21SE. One costing $379 and the other $299. I was amused by the specs on your unit, but having tried a Sampson (did not work at all well), I was hesitant to try yours. Better stick to Stereo Audio equipment, ya know. But I had to prove your specs wrong. To my amazement, your HP4 sounded as good as the Creek and the Grado. Very very clean and loud. I can't believe you put 150 mW per channel, @52 ohms, to four headphone outputs and offer such a quality unit for this low price. My $345 Grado 325 headphones, as well as my $375 Senn. 600's never had it so good. The Grados are weak in bass and the Senn's put you back in the tenth row of seating with muted clairity. SOooooo, I also tried two of your EQ3B's (Tri band EQ unit-MONO), also at a very low price. Simply astounding. Now I can tweak an almost great headphone to perfection. Or a mediocre pair of cans to greatness. Your EQ unit offers gain, frequency, and bandwidth adjustment for each of the lo, mid, and high settings. Fantastic. Ultra-quiet also.