XLR vs TRS vs TS Cables: Balanced vs Unbalanced Audio

What is the difference between XLR, TRS and TS cables?

The difference is the number of conductors. XLR and TRS carry three (two signal wires plus a shield), which is what a balanced connection needs, while TS carries two (one signal wire plus the shield), so it is always unbalanced. Rane describes a balanced line as three separate conductors: two signal wires, plus and minus, and a shield^[1].

The letters describe the plug. TS stands for tip-sleeve, the classic guitar cable. TRS adds a ring between tip and sleeve, which you can spot as two thin black bands on the plug instead of one. XLR is the round, latching three-pin connector used on microphones. On a standard XLR mic cable, pin 2 is hot, pin 3 is cold and pin 1 is ground (shield); Audio-Technica's AT2020 datasheet uses exactly that convention^[3].

How does a balanced cable cancel noise?

A balanced cable sends the signal twice, once normal and once polarity-inverted, and the receiving input keeps only the difference between the two. Any hum or buzz picked up along the way lands on both wires equally, so it cancels out at the input.

SoundGuys explains the mechanism as differential signalling: the input stage amplifies only the difference between the hot and cold lines, and anything common to both is rejected. The two conductors are twisted together so they occupy the same space along the run and pick up the same interference^[2]. How well an input does this is measured as its common-mode rejection ratio, or CMRR^[2].

This matters most for microphones. A mic puts out only a few millivolts, and the preamp then adds a lot of gain, which would amplify any induced noise along with your voice^[2]. That is why every professional mic cable is balanced XLR. Rane goes further and argues that only balanced interconnects can reliably deliver hum-free results^[1]. The same pair of wires also carries phantom power to condenser mics, which is covered in phantom power explained.

Is a TRS cable always balanced?

No. A TRS cable is only balanced when it connects a balanced output to a balanced input. The same three-conductor plug is also used for unbalanced stereo, with left on the tip and right on the ring, which is how every pair of headphones works^[2].

Your interface shows both uses side by side. On the Scarlett 2i2 4th Gen, the rear speaker outputs are balanced ¼-inch TRS jacks, while the headphone output is a TRS jack carrying stereo^[4]. Plug a TRS cable into either and it fits, but only the first is a balanced mono connection. The front instrument inputs accept both unbalanced TS and balanced TRS jack cables^[4].

Mixing the two worlds is where trouble starts. Rane warns that balanced and unbalanced interconnects are not truly compatible, and that connecting unbalanced gear into balanced gear does not make it quieter^[1]. A TRS cable between an unbalanced synth output and a balanced input is still an unbalanced connection. It will usually work, but the noise rejection you paid for in the cable is not there.

Which cable should you use for mics, monitors and instruments?

Match the cable to what both ends support. Balanced where both devices are balanced, TS where the source is an instrument or an unbalanced output. Check the jack labels or the manual for the words balanced, unbalanced, TRS or TS.

• Microphone to interface XLR female to XLR male. Never use a jack adapter on a condenser; phantom power only travels to the XLR inputs on interfaces like the Scarlett 2i2^[4].
• Interface to studio monitors TRS to TRS, or TRS to XLR if the monitor has XLR inputs. Yamaha's HS series, for example, accepts balanced XLR and balanced phone (TRS) inputs^[5]. Focusrite recommends TRS cables for balanced connections from the 2i2's outputs^[4].
• Electric guitar or bass TS instrument cable into a Hi-Z or Inst input. On the 2i2, the Inst button switches the front jack input to instrument level^[4].
• Synth, drum machine, sampler TS if the outputs are unbalanced, TRS if the manual says balanced. Stereo instruments need two cables, one per side; see recording hardware synths into your DAW.
• Headphones The headphone cable is a stereo TRS or a 3.5 mm plug with a ¼-inch adapter. Focusrite notes that headphones with TS or TRRS connectors are unlikely to work properly from the 2i2's TRS headphone output^[4].
• Turntable or DJ controller RCA to TS or RCA to TRS into line inputs. The connection is unbalanced at the source, so keep the run short.
• Outboard compressor on a mixer insert An insert cable, covered in the next section.

For a full walkthrough of a typical beatmaker desk, from interface to monitors to MIDI controller, see how to connect home studio gear.

What is an insert cable and when do you need one?

An insert cable splits one TRS plug into two TS plugs so a single mixer or interface jack can send audio out to an effect and bring it back. Hosa describes its insert cable as designed to connect a channel insert on a mixing console to an effects processor with unbalanced phone jacks, with the leads labeled tip (send) and ring (return)^[6].

The key detail is that an insert point is unbalanced by design. The tip carries the signal out and the ring carries it back, so there is no spare conductor for a balanced pair. Rane lists insert points alongside effect loops as typical unbalanced connections^[1]. Keep insert runs short and route them away from power cables.

1. Find the insert jack
   Look for a jack labeled Insert on the mixer channel or interface. Many budget interfaces do not have one, in which case you use a separate output and input pair instead.
2. Plug in the TRS end
   The single TRS plug goes into the insert jack.
3. Connect the send
   The TS plug marked tip (send) goes to the input of your compressor, EQ or pedal.
4. Connect the return
   The TS plug marked ring (return) goes to the output of the same device.
5. Test with the effect bypassed
   Level should match the dry signal. No signal usually means send and return are swapped.

What should you check before buying audio cables?

Buy the right connector types and lengths first, then decent build quality. Home-studio cable problems almost always trace back to the wrong cable type, a damaged connector or a bad solder joint, not to exotic materials.

• Measure before you order Measure the actual path around your desk and add about 30 percent. A cable pulled tight strains the connectors every time you move a stand.
• Keep unbalanced runs short TS and RCA runs have no noise cancellation, so keep them as short as your layout allows and away from power strips. Balanced runs can be much longer.
• Check the pin wiring on XLR Audio-Technica warns that all mic cables must be wired consistently, pin 1 to pin 1 and so on, to avoid phase cancellation and poor sound^[3].
• Choose metal strain reliefs The point where the wire enters the plug takes the most strain. A solid strain relief and a metal shell hold up to years of plugging.
• Buy monitor cables in pairs Two identical TRS or TRS-to-XLR cables keep left and right consistent and make troubleshooting easier.
• Label both ends Tape labels like MIC 1 or MON L save time when something goes silent mid-session.

If your setup still hums or buzzes with the right cables in place, the cause is often a ground loop rather than the cable type. Audio cables and ground loop fixes covers how to diagnose and fix it safely.