Sound Storm LaboratoriesS4EQ 4 Band Pre-Amp Car Audio Stereo Equalizer - Gold-Plated Front/Rear and Subwoofer Outputs

Works fine BUT- I had same problem as others. One of the RCA plugs broke loose inside when I installed my cables, messing up the master volume.I've got the cables zip-tied at the rear which keeps the circuit board from shorting out.The RCA cables I used fit very tightly and were difficult to install. From now on when I install cables (to any unit) I will install them onto another device first, like an old CD player to make sure they are not too tight. You shouldn't have to use so much force that it breaks the unit you are installing them on.I don't think it was the fault of the EQ here. Everything about the unit seems to be of very good quality and the EQs performance is great. Clean and clear sound, and the preamp voltage rise really cranks up my amplifier's output.I really like this EQs variable sub frequency control. It allows you to change the crossover frequency right from the dash instead of resetting the amp. Works awesome-I can optimize hz values for different music on the fly. It makes a huge difference in dialing in the perfect sound, song to song.The rest of of this EQs performance is very good too. Master volume, sub volume and f/r fader-all good. The four band EQ boost/cut +/-18db provides a definitely noticeable difference when you dial the controls.Overall a very good unit. Would purchase again. The variable sub frequency control really gets it done-5 stars.Update Review 2-25-15Purchased another S4EQ for another vehicle. Pre-installed my cables onto the old head unit before using them on the new EQ. No problems.Using the EQ on a sub only signal from my head unit then to an amp. EQ door speakers with a seven band Clarion. Works great. Love controlling volumes AND sub frequency (S4EQ) using three easy to reach dials. No having to read displays while I'm driving.SSL S4EQ-Spot on. Perfect for a great price. Would definitely use again.

This little inexpensive EQ greatly improved the sound quality coming out of my phone/bluetooth receiver combination in my classic musclecar ride. For some 60's and 70's muscle cars, there aren't very many great options for head units that does not require cutting the dash. That's not a route I wanted to take, so I set out piecing together a sound system for my '74 Plymouth Duster after trying out and returning a RetroSound Redondo stereo.What I pieced together was this EQ along with an NVX bluetooth receiver (reviews aren't great on Amazon, but it's crystal clear) and an NVX 5 channel amplifier. Before I purchased this EQ, I was only using the NVX bluetooth reciever and amplifer along with my phone. The sound was very flat. The bass wasn't punchy and the highs not very crisp. So, I did some research and was convinced that I needed an EQ.If you're building setup like mine, then here's why you need and EQ like this one. What it does it separates the the lows and the mids/highs and boosts the signal to the amplifier. It also allows you to adjust the balance between the front and rear. Obviously, it also allows you to boost the signal for low, mid-bass, mids, and highs.After I added this EQ to my cobbled together sound system it made my music come ALIVE! The highs were nice and crips, the bass both punchy and boomy too. Mids are crystal clear. I listen to a variety of music from classic rock, metal, rap, 80's, ska, salsa, mambo, and more. This little thing definitely made it all come alive.So you might be wondering what speakers I'm running. In the front kick-panels, I'm running Pioneer 4"x6" speakers, in the rear package tray I'm running Kicker 6"x9"s and in the trunk I'm running a Kicker 10" subwoofer in a truck box since it fits the best.Best bang for your buck right here!!

The instructions are extremely vague as to how to make adjustments to clean up distortion and noise.Mine was turned wide open on the input adjustment settings. Once I turned that down it cleaned up quite a bit. I don't know if it will have ground loop and or alternator noise, but I have filters for those issues.For EQ they're designed to shape audio sounds for personal taste and room/cabin acoustic 's.If you use cheap speakers, your quality of sound will be far less than it could be. If your putting together a vehicle sound systems and need a EQ, do yourself a favor and buy good quality speakers. For the price point and quality of sound, Kenwood makes some of the best speakers available at any price.Hopefully I have been of some help with any questions about this product. 73 Earnest K5EWM.