Connect a laptop, iPod, iPhone, iPad, MP3 player, Android tablet or phone to your pro audio mixer, amplifier, or other device.

Have you ever used a stereo-to-mono "Y-cable" or TRS (Tip/Ring/Sleeve)-to-TS(Tip/Sleeve) cable for combining two audio outputs together, or for summing the Left and Right channels from a single stereo output to mono? For example, maybe you wanted to connect the stereo outputs of your CD player, laptop, iPod, iPad, Android tablet or phone into a single 1/4" TS input channel on an audio mixer. Or maybe you needed to sum a stereo signal to mono for connecting to a single subwoofer. Or maybe you do some recording at home and like to check your mixes in mono on a "grot box" like the Auratone or one of its clones (Avantone Mix Cube, Behringer Behritone, etc.). If you're like me, you've probably done this, but what you may not know is this:  a Y-cable used to SPLIT a signal into two outputs is being used properly. A Y-cable used to MIX or COMBINE two signals into one input is being abused, and may even damage your equipment!

Here's the rule: outputs are low impedance, and must only be connected to high impedance inputs. You should never tie two audio outputs directly together. If you do, each output tries to back-feed into the other, and drive the very low impedance of the other output, forcing both outputs into current-limit. At best, this can cause signal loss, audible distortion (popping and clicking sounds), and weird phasing effects. At worst, it can actually cause damage to your equipment!  

I learned this the hard way when gigging with my band. We were playing a large outdoor picnic and using our own PA system. We normally run some backing tracks off of one of our band member's iPhone. In this case, we were using an Android tablet instead. We connected it up to the system using a standard 1/8" TRS stereo to 1/4" TS mono cable (HOSA CMP-105). I had used this same cable in the past with other devices without any trouble. But when we started the tracks, we were getting constant pops and clicks, the sound was distorted, and everything had a weird phase-y sound to it (think phaser pedal for an electric guitar). We fooled with it for a few minutes, but never could find the problem, so we ultimately had to abandon using the tracks at all for the gig. I later did some research and testing and discovered that what I needed was this cable. It aims to solve the problems listed above.

It includes the following:  5' (five feet) of low-profile, dual-conductor shielded microphone/line cable. On one end is a 1/8" 3.5mm stereo TRS plug for connecting to the stereo output of your iPod, iPad, Android tablet, etc. On the other end is a 1/4" 6.35mm mono TS plug for connecting to the input of your other device (mixer, amplifier, etc.) Inside this plug are two resistors (see pics) that are used to sum the signals from the left and right output channels, sending the combined mono signal to the tip of the 1/4" mono TS plug. The sleeve is connected to the shield of the cable like normal. So you get a perfectly summed mono signal with no distortion or phasing, and it won't damage the outputs of your other device. You'll note from the pictures that I also use high quality connectors and heat-shrink tubing to cover the resistors and prevent shorts inside of the 1/4" TS plug.

From the research I've done, there are no off-the-shelf cables from any major cable manufacturer on the market that do what this cable does. It's a widely-known problem, but no one has addressed it--until now. There are other cables that claim to do it, including the Hosa CMP-103, CMP-105, and CMP-110, but none of them do it properly. Those cables simply short the tip and ring together, but do not utilize any resistors.

How our cables are different: you may have seen some other mono summing cables online that are constructed with resistors (their name might bring to mind a fishing trip, LOL) . These cables appear to have a low price, but that's for a 1-ft length cable. For a 6-ft cable (ours are 5-ft in length), the price is pretty much the same as ours. However, their cables are built with cheap connectors that have a pinching/clamp style strain relief, and then they cover them with heat shrink. This type of strain relief does not grip the cable firmly and can even damage the cable over time with use. Their 1/8" plugs often do not fit snugly in the headphone jack of some devices, and the outer shell of the plug is too large to fit many devices if the device is inside of a case (e.g. phone or tablet). Our cables use a low-profile 1/8" connector with molded strain relief that fits firmly in most devices, and the outer part of the plug is small enough to fit the headphone jack in virtually any device--even if it's in its case. Also, our 1/4" plugs use a chuck-style strain relief that provides superior gripping action without damaging the cable in any way when compared to the pinch/clamp style relief. Our cables are the original mono summing cable with resistors, which we've been selling now for many years with hundreds of satisfied customers. Please take this into consideration when buying a cable. 

For further reading on this subject, just Google search "Why Not Wye", which will lead you to an article on the Rane website that explains the problem and its solution in more detail.

Contact me with any questions.