Sub connection question

[connta]

Hello guys, i just got myself a SVS PB-1000 sub and i connected it over single LFE RCA cable. Now i see that my AVR has 2 subwoofer outputs (one labeled "SUBWOOFER" and another labeled "PREOUT" right below it), its an Onkyo TX-NR646. Every guide says to just connect single RCA from SUBWOOFER on AVR to LFE on the sub but i was wondering what would happen if i connected both outputs from the AVR to the sub? Theres probably a reason no one touches this in numerous guides/videos that i looked at but the curiosity is eating me as to why, what would actually happen with such setup?

Also, anything i should be looking at cables for a ~3m connection? Im currently using a standard, decent, mono RCA (it aint certified digital) that i already had at home, should i look at something better or is this fine?

 

[eljr]

You can use either from what I can see. It's kind of silly how it's labeled, IMHO.

Just connect the sub out to the sub.

and then,

enjoy your holiday!

 

[Speedskater]

Also, anything i should be looking at cables for a ~3m connection? Im currently using a standard, decent, mono RCA (it aint certified digital) that i already had at home, should i look at something better or is this fine?

If it's a coax with a heavy braided shield, it will be fine.
* * * * * * * * * * *
I wonder if the PRE out and the SUB out are both from the same point int the circuit?

 

[connta]

Its not even coax i think, coax is usually a lot more rigid cable. Its a standard, flimsy RCA tho it claims OFC and gold plated contacts (they are yellow, ill give em that) im not so sure those claims are correct.

I got few patches of coax left over from ISP installation and im sure i got a couple of RCA conenctors somewhere, gonna do a patchwork coax vs this and if its the same, i got my answer. Any idea what would be best cable test (lol) in REW?

EDIT:

I wonder if the PRE out and the SUB out are both from the same point int the circuit?

Same, should i try the preout and see if it behaves any differently? Aint gonna fry anything?

 

[Leemix]

The connection to the sub is analogue not digital.

 

[connta]

That much is clear, lol. My point was that any RCA cable can carry digital or analog signal but the ones certified as digital are usually better built with more shielding.

 

[William Lemmerhirt]

Kinda dumb how it’s labeled but it looks like simply a second sub out. AFAIK Onkyo doesn’t eq two subs separately so that’s likely just an internal splitter. If you do hook both of them up, the only thing that will happen is you’ll raise the input voltage. So you’ll need to lower the sub channel by probably 3db. This will not change the subs overall output capability though. This dual connection can be helpful if a sub has trouble waking up, but usually recalibrating so the subs level in the AVR is higher. Like -5 or so.

 

[MTVhike]

I think the sub cable is the least restrictive - the only possible defect is that if there's not enough shielding, you may pick up some hum. (I'm assuming both your potential sub connections have RCA connections).

 

[William Lemmerhirt]

I think the sub cable is the least restrictive - the only possible defect is that if there's not enough shielding, you may pick up some hum. (I'm assuming both your potential sub connections have RCA connections).

Exactly. The bandwidth required for subwoofer signals is very very small.

 

[connta]

On the hum issue, i have only encountered that when the electrical installation is shoddy or when people use USB powered sound sources since usb tends to have bad power on most budget motherboards that go in HTPCs. Or if you live under major power lines, that will do it.

Im really not using high powered system nor are there that many devices to create that much EMI as to translate into induction hum. If cables are not coiled this really should not happen with modern gear that is designed to mitigate EMI and usually also has some form of EMI shielding. Remember how cellphones used to excite audio devices but that doesnt happen for a while now?

Got a friend to bring a Cordial double shielded coaxial RCA and i did few REW measurements, both cables gave 100% identical output at 100 dB. No difference in signal to noise ratio either, el cheapo cables win.

I have to do a bit of moving the furniture since it seems my best position for the sub (determined by crawl) is currently taken. If the sub is placed along the wall and it is completely not corner loaded how close to the wall would you recommend placing it? Should it be flush to the wall or is there some rule of thumb to start with?