Long speaker cable or RCA and does length matter

[conqueeftador]

Need a few runs of 10m cables, be it RCA or speaker cable. No balanced option available. A quick google before sent me down the path of longer RCAs. So I ran some and cheaper RCA cables, away from power sources and the are making odd noises. Previous builds I've ok success with long speaker cable runs.

Also would it matter if front left is say 1m and right is 3m?

 

[antcollinet]

If you have to choose between long RCA signals, and long speaker cables - always go with long speaker cables.

1 - higher voltage/current signals and low impedance circuit so much less susceptible to noise coupling in.
2 - more importantly there is no earth to a speaker so no chance of creating long earth loops.

Different length speaker cables might cause a small channel imbalance but I doubt it would be audible with just a 2m difference -as long as the wire is thick enough.

 

[Chrispy]

I've gone speaker cable when doing that length to subs (rack amps). 10m is with routing, direct distances are 1/3 m? Are you asking if differences in length will be a consideration?

 

[Kal Rubinson]

If you have to choose between long RCA signals, and long speaker cables - always go with long speaker cables.

1 - higher voltage/current signals and low impedance circuit so much less susceptible to noise coupling in.
2 - more importantly there is no earth to a speaker so no chance of creating long earth loops.

Different length speaker cables might cause a small channel imbalance but I doubt it would be audible with just a 2m difference -as long as the wire is thick enough.

If noise was the only issue, I might agree but noise issues can be dealt with by proper grounding, proper shielding and, if necessary, balanced interconnect cable. OTOH, increasing speaker cable length exacts power losses due to increased series resistance which also compromises damping factor.
...........................not that any of this is likely to be audible unless the lengths are reeeeeeeealy long.

 

[DonH56]

I usually do long interconnects and short speaker cables. I prefer to keep the driving impedance the speakers see low, more to terminate the crossover than for loss (which is usually negligible). Aside from controlling back-EMF, higher impedance from long speaker cables can change the frequency response of the speaker slightly -- how much depends very much upon the speaker, as well as amplifier and cables (cables are usually insignificant). That is also the reason I usually match speaker cable lengths, but in the real world that too is negligible (more me being anal) especially for short runs (10 m is fairly short).

For interconnects, I usually use XLRs for long runs and/or when the power amps are on a different circuit to deal with ground loops, but there are also lots of line-level ground isolation units available now (and few balanced-output consumer products). I have some ancient cheapie 50' RCA cables I have used many times that worked fine unless I was near a radio station or using them at some live venue and needed better shielding. The output impedance from line-level sources is much higher than from a power amp but still very low compared to an open circuit (antenna), usually 100 ohms or less at the driving end (admittedly much higher at the receiving end).

FWIWFM - Don

 

[clearnfc]

Need a few runs of 10m cables, be it RCA or speaker cable. No balanced option available. A quick google before sent me down the path of longer RCAs. So I ran some and cheaper RCA cables, away from power sources and the are making odd noises. Previous builds I've ok success with long speaker cable runs.

Also would it matter if front left is say 1m and right is 3m?

Yes long rca will work find, speaker cable woll do as well, just go for the cheaper option. Like you said, dont run them next to power lines and it will be ok.

Oh, just to add, if you are going through walls, you will need to consider the size of the rca connectors. Will need to drill a bigger hole. If not, you will have to run bare cables and terminate them later.

 

[antcollinet]

...........................not that any of this is likely to be audible unless the lengths are reeeeeeeealy long.

Exactly - whereas noise from ground loops is very audible. And with unbalanced connections can be very difficult to resolve.

 

[freemansteve]

I tested my system components when they first arrived, using 50cm long RCA interconnects for line-level signals and 2m speaker cables. These were parts left over from previous times. When happy it sounded OK, with the main speakers in their final destinations, but with wiring blu-tacked in place, I wired everything properly in place, including 1x6m speaker wire, 1x3m speaker wire, 1x5m RCA lead to one sub, 1x2m RCA lead to other sub, 1x5m RC lead to headphone socket box on a wall, 1x1.5m RCA for occasional AUX inputs - and cannot detect any issues compared with the testing setup. But then I wouldn't expect any possible problem other than noise pickup on the RCA wiring, and there was none I could hear.

I think it is possible to get a bit too worried over varying cable lengths between L&R channels over the short runs you get for most domestic setups... Plus, sometimes you don't get a choice unless seeking a divorce

 

[DonH56]

Exactly - whereas noise from ground loops is very audible. And with unbalanced connections can be very difficult to resolve.

I do not disagree, but I am curious how large the problem is in the UK? I know the power grid is different but no details (on the wrong side of the pond). And are there similar solutions available? I was in Europe (mainly Germany) some years back and noticed a lack of safety ground terminals but was focused on other things than the power grid.

The three most common solutions for the average audiophile I have seen (here, in the USA) are:

1. Line-level isolators, e.g. https://www.amazon.com/RECOIL-2-Cha...1649248479&sprefix=ground+isol,aps,148&sr=8-7 or https://www.amazon.com/Compact-Mini...1649248578&sprefix=ground+isol,aps,148&sr=8-6 (there are also active DI boxes but those are seen more in pro use);
2. Power-line isolators, e.g. https://www.amazon.com/Ebtech-Hum-P...649248578&sprefix=ground+isol,aps,148&sr=8-10 ; and,
3. Cable isolators (here, cable/satellite boxes are often the main culprit) e.g. https://www.amazon.com/Ground-Loop-...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

I have not used any of these specific devices save the Hum-X but there are a myriad of similar products available. I would expect line-level and cable isolators to work "anywhere" but not the power-line isolators (have to get one that works for your power outlets).

The solutions are fairly inexpensive and simple to install but of course you have to know which is the one to use. IME many audiophiles do not know what a ground loop is or sounds like, let alone why it appears, so step one is identifying the problem. Then troubleshooting to find the specific cause (which can indeed be frustrating, especially for someone with no experience). In my system, the rear (sub) amps use XLR connections but when I tried RCA there was no ground loop noise despite them being on different circuits. Interestingly enough, it is the front subs, on the same circuit and with only RCA connections available, that had a ground loop problem until I did some rework to fix it.

I think it is possible to get a bit too worried over varying cable lengths between L&R channels over the short runs you get for most domestic setups... Plus, sometimes you don't get a choice unless seeking a divorce

I am/was very big on matching even for short runs, partly because I prefer to keep longer cables in case I move things later, but have fought the designer's instinct to make everything "perfect" for many years. I took another look fairly recently after being challenged here and discovered my fear was largely irrational. Results here: https://www.audiosciencereview.com/...ffect-of-speaker-cable-length-mismatch.20150/

 

[Speedskater]

Long RCA cables (lets say well over 20 feet) and components that are powered from different AC circuits are often subjected to 'Common Impedance Coupling' noise. Both Bill Whitlock and Kurt Denke write about this.

 

[Kal Rubinson]

Exactly - whereas noise from ground loops is very audible. And with unbalanced connections can be very difficult to resolve.

Agreed but I've had very few such issues over many decades of audio systems.

 

[clearnfc]

Exactly - whereas noise from ground loops is very audible. And with unbalanced connections can be very difficult to resolve.

Imho, ground loop is usually not that big of an issue these days and i would say quite easy to resolve. I dont like to put isolators on the signal line (i feel it degrades audio but thats just me). So i use them at the mains instead. Each equipment has its own ground isolator. DIY them myself.

 

[Ricardus]

COUGH!

 

[antcollinet]

Agreed but I've had very few such issues over many decades of audio systems.

Thing is - over decades we've mainly been using RCA over short distances between stacked analogue audio devices. In these days of powered speakers and subs, people are running RCA leads over much longer distances - and where those powered devices have earths, it is common to find issues. PC's as sources are also horrible when ground loops occour - because not only are they usually earthed, so with an earthed amp you get a ready made ground loop. Then with their power hungry CPUs and graphics cards, they are good sources of higher frequency magnetic fields to couple into the loop.

Personally I had a serious ground loop problem when my PC was the (analogue) source, and the amp was only 2m of RCA away. An isolation device only attenuated the noise (and rolled off the highs). Solved with optical connection.

 

[antcollinet]

Imho, ground loop is usually not that big of an issue these days and i would say quite easy to resolve. I dont like to put isolators on the signal line (i feel it degrades audio but thats just me). So i use them at the mains instead. Each equipment has its own ground isolator. DIY them myself.

I do hope your ground isolator isn't disconnecting, or putting imedance in, the safety ground.

By far the best way of removing the problems caused by ground loops is to use optical digital connections, or balanced interconnect between devices.

 

[Kal Rubinson]

Thing is - over decades we've mainly been using RCA over short distances between stacked analogue audio devices. In these days of powered speakers and subs, people are running RCA leads over much longer distances - and where those powered devices have earths, it is common to find issues.

Sure, that can happen but I have been running mixes of RCA and XLR outputs over 10m lengths in both my MCH systems without issues. If it happens, one can fix it with a little effort.

PC's as sources are also horrible when ground loops occour - because not only are they usually earthed, so with an earthed amp you get a ready made ground loop. Then with their power hungry CPUs and graphics cards, they are good sources of higher frequency magnetic fields to couple into the loop.

Of course, that is another possibility but my PCs are restricted to digital in and digital out.

Personally I had a serious ground loop problem when my PC was the (analogue) source, and the amp was only 2m of RCA away. An isolation device only attenuated the noise (and rolled off the highs). Solved with optical connection.

There you go.

 

[paddycrow]

and does length matter​

Trying not to laugh...

 

[antcollinet]

Trying not to laugh...

Girth: Much more important.**


** Lower resistance at least, electrically

 

[Lambda]

I usually do long interconnects and short speaker cables.

This is also what i would do. but i would also uses balanced interconnects.

if this is not an option maybe long speaker cables are not as bad..

Also would it matter if front left is say 1m and right is 3m?

NO... but i personalty would avoid it and just used the same 3m cable for both sides.