What is a patch cable and should I be using one for my subwoofer?

[rask33]

Is it just a cable with two different ports on either end? I need to connect my sub to a processor that has TRS ports on it. The sub in turn has XLR and RCA ports. I was going to get an XLR to TRS cable to connect but I wanted to make sure this is a good way to do this. Essentially my concern is avoiding EMI; there are a lot of cables around in the desired path.

So specifically subwoofer cables seem have denser/more quality shielding in order to avoid interference. But they all seem to be RCA. My understanding is that the purpose of a balanced connection is to avoid EMI, so that is why I went that route with my processor (miniDSP). So that is my question.

 

[fpitas]

Any TRS to XLR cable should work. I usually just go for Amazon basics. Blue Jeans might have a spiffier one if that appeals to you. Still sound the same, though.

 

[rask33]

Any TRS to XLR cable should work. I usually just go for Amazon basics. Blue Jeans might have a spiffier one if that appeals to you. Still sound the same, though.

Yeah I know they all sound the same m8, but again, my very basic understanding atm is the more expensive cables are better at shielding against EMI, which is what I'm after. The sub will be placed near an electric panel, and the cable will run towards and possibly cross speaker/amp cables and a thirsty PC.

 

[fpitas]

Yeah I know they all sound the same m8, but again, my very basic understanding atm is the more expensive cables are better at shielding against EMI, which is what I'm after. The sub will be placed near an electric panel, and the cable will run towards and possibly cross speaker/amp cables and a thirsty PC.

Generally, any competent shielded twisted pair cable like used with XLR has excellent EMI rejection. I doubt you'll have trouble.

 

[DVDdoug]

I was going to get an XLR to TRS cable to connect

That's good. XLR and TRS connectors both have 3 conductors and can be used for balanced connections. RCA connectors have only two conductors and are for unbalanced connections.

understanding atm is the more expensive cables are better at shielding against EMI, which is what I'm after.

I wouldn't worry about it unless you have a problem. Most "audio" cables will be properly shielded. Balanced connections are naturally more immune to noise than unbalanced connections. Audio outputs are usually low-impedance (even when connected to high-impedance inputs) and this helps to kill any picked-up noise. And line-level signals are a lot stronger than microphone signals so that means if noise is picked-up you have a better signal-to-noise ratio. A mic preamp amplifies the signal and the noise together, making the noise more audible. But balanced mic cables are rarely a problem either.

Balanced connections are also highly immune to noise caused by ground loops. In general, you are more likely to get hum from a ground loop than from EMI.

What is a patch cable...?

As far as I know, it's a vague term. Usually for a short-temporary connection like the old-time telephone switchboard where the operator would manually "patch" someone into the correct extension for the duration of the call.

A recording studio might have a patch panel so they can easily make various connections to the permanently-installed wires or equipment without changing connections on the back of the equipment, etc.

 

[fpitas]

Another way to do it would be to use a standard XLR to XLR cable, with a TRS adapter at one end. Might be easier to get or cheaper, dunno.

 

[rask33]

Generally, any competent shielded twisted pair cable like used with XLR has excellent EMI rejection. I doubt you'll have trouble.

That's good. XLR and TRS connectors both have 3 conductors and can be used for balanced connections. RCA connectors have only two conductors and are for unbalanced connections.


I wouldn't worry about it unless you have a problem. Most "audio" cables will be properly shielded. Balanced connections are naturally more immune to noise than unbalanced connections. Audio outputs are usually low-impedance (even when connected to high-impedance inputs) and this helps to kill any picked-up noise. And line-level signals are a lot stronger than microphone signals so that means if noise is picked-up you have a better signal-to-noise ratio. A mic preamp amplifies the signal and the noise together, making the noise more audible. But balanced mic cables are rarely a problem either.

Balanced connections are also highly immune to noise caused by ground loops. In general, you are more likely to get hum from a ground loop than from EMI.

cool, thanks guys.

 

[rask33]

Another way to do it would be to use a standard XLR to XLR cable, with a TRS adapter at one end. Might be easier to get or cheaper, dunno.

Yeah what is the physical difference between this and a patch cable? What's going on with the wires inside the insulator in a patch cable?

 

[fpitas]

Yeah what is the physical difference between this and a patch cable? What's going on with the wires inside the insulator in a patch cable?

In a pro environment, any of these might be called a patch cable. Unless you have some other definition over there across the big water.

 

[rask33]

In a pro environment, any of these might be called a patch cable. Unless you have some other definition over there across the big water.

so the only difference is the adapter on either end? balanced = balanced?

 

[fpitas]

so the only difference is the adapter on either end? balanced = balanced?

Generally pro audio only uses balanced connections, for the reasons described above by DVDdoug. Even high-end home hi-fi is beginning to appreciate it.

 

[twsecrest]

Is it just a cable with two different ports on either end? I need to connect my sub to a processor that has TRS ports on it. The sub in turn has XLR and RCA ports. I was going to get an XLR to TRS cable to connect but I wanted to make sure this is a good way to do this. Essentially my concern is avoiding EMI; there are a lot of cables around in the desired path.

So specifically subwoofer cables seem have denser/more quality shielding in order to avoid interference. But they all seem to be RCA. My understanding is that the purpose of a balanced connection is to avoid EMI, so that is why I went that route with my processor (miniDSP). So that is my question.

If you in any way use RCA for any of the connections, you will not get a balanced connection.
Even if one of the connectors is XLR
Better to just go RCA to RCA.

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[Speedskater]

The best XLR balanced interconnects use bulk cables from the major industrial manufactures. Manufactures like Belden, Canare & Mogami.
While some audiophile & boutique cable brands use those major mfgs. to make their cables, others that make their own, will most likely make poorer cables with regards to nose and interference problems.

 

[Grumpish]

The best XLR balanced interconnects use bulk cables from the major industrial manufactures. Manufactures like Belden, Canare & Mogami.
While some audiophile & boutique cable brands use those major mfgs. to make their cables, others that make their own, will most likely make poorer cables with regards to nose and interference problems.

The vast majority of studios are cabled through out with cables from Belden, Canare,, Mogami, no-name bulk Ethernet cable, and connectors from the likes of Neutrik and Studiocraft.

 

[MaxwellsEq]

A patch cable is a temporary (usually) connection between two sets of fixed wiring. Sometimes one end is into fixed equipment and the other end is into the fixed wiring. It's used in telecoms and datacomms a great deal (e.g. the building-wide flood-wired Ethernet UTP cabling and the ports driving the cabling). Making patch changes is quick and easy and doesn't require a building re-wire for every small change. You could argue that a mains cable is a patch between your fixed mains wiring and your portable kit. Studios make heavy use of patching between fixed video and audio wiring and control surfaces.

 

[rask33]

A patch cable is a temporary (usually) connection between two sets of fixed wiring. Sometimes one end is into fixed equipment and the other end is into the fixed wiring. It's used in telecoms and datacomms a great deal (e.g. the building-wide flood-wired Ethernet UTP cabling and the ports driving the cabling). Making patch changes is quick and easy and doesn't require a building re-wire for every small change. You could argue that a mains cable is a patch between your fixed mains wiring and your portable kit. Studios make heavy use of patching between fixed video and audio wiring and control surfaces.

Thanks for answering my question. So is it detrimental to long-term performance if I'm using a quality patch cable for my home system?

 

[JayGilb]

Thanks for answering my question. So is it detrimental to long-term performance if I'm using a quality patch cable for my home system?

No.

 

[Zek]

...if I'm using a quality patch cable...

Perhaps it would be good for the sake of understanding if you specified which patch cable you meant.

 

[MaxwellsEq]

Thanks for answering my question. So is it detrimental to long-term performance if I'm using a quality patch cable for my home system?

It shouldn't - if using good quality cable (I've been pleased with Mogami 2549) and good quality connectors (I've found Neutrik XLRs to be reliable).

It may help to realise how many patches and matrix-junctions the music has gone through before release. I've attached a picture of an audio patch bay in a studio. The connectors are Tip-Ring-Sleeve (TRS) balanced "double-enders".