Because the cable itself doesn't determine whether a signal is balanced or unbalanced. This is determined by the circuitry design of the equipment-opamps, transformers, etc. Balanced gear is, on the whole, moure expensive to manufacture.

that said ...

if you have the choice, use balanced.

ps - anyone know if theres a practical limit to the length of a balanced trs cable without losing quality?

justfei wrote: okay, im new to audio and live sound so bear with me.

just a silly question about the difference and use between balanced and unbalanced cables.

since balanced cables reject noise, why not everything be connected using balanced cables instead of unbalanced ones?

nope... the balanced cables only can be use wit balanced gear connection .. if u're using the cables wit unbalanced gear (like guitar & other instruments), there will be no effect ... to reject more noise, use high quality cables (belden etc) ...

Balanced cables

rockstardave wrote: that said ...

if you have the choice, use balanced.

ps - anyone know if theres a practical limit to the length of a balanced trs cable without losing quality?

As long as both ends are operating balanced circuitry. a balanced signal can travel up to 2000m before the quality starts to degrade.

2000 METERS?!?!?! That's over a friggin' mile! The actual useable distance is dictated by a host of variables, not just the fact that it's "balanced". The type of balancing circuit (active or transformer-based), the average operating level (mics and line levels aren't the same in this regard), the quality of the cable (can you say, "capacitance"?), not to mention the amount of RFI in the operating environment, will all determine the max useable distance. I have experienced situations where we couldn't get much over 100 feet on a mic snake without noticeable signal loss, yet the engineers at E-V said "600 feet" (200 meters)...

more like 200 meters

Some old designers will tell you that a balanced circuit will not sound as good as an unbalanced one. Rupert Neve used to think this way, and most of his consoles were unbalanced.

Just a note on cable lengths, the longer the cable the higher the resistance (and hence lower signal levels among other things). If you need to go longer distances one way to offset this is use a larger diameter (lower gauge) conductor, as the total resistance depends not only on the length but the diameter, smaller the diameter the higher the resistance. Specifically, r~A/l where A is cross sectional area and l is length.

Opps, on vacation so I had a brain fart, the relationship should be r~l/A so as the diameter gets bigger (A gets bigger) the resistance goes down, or if the length gets longer the resistance goes up. Sorry, this was bugging me after reflecting on my answer.