Where to split the subwoofer feed?

[Boomzilla]

If I use my Oppo's bass management, the subwoofer feed becomes monophonic & plays from a single "sub" output jack.

But I have two subs that I'd like to drive from that same feed. The two hookup options available are:

1. Install a splitter at the Oppo & run dual (10-foot long) interconnects, one to each subwoofer. or

2. Run a single 10-foot wire from the Oppo to the subwoofers & install a splitter immediately before connecting the two subs.

Which option reduces the likelihood of ground-loop hum the most, if either?

Thanks - Boomzilla

[hosko]

Its in parallel so the config with the least amount of cable should be the best option.

[Deleted]

Nov 7, 2016 20:46:53 GMT -5 Boomzilla said:

If I use my Oppo's bass management, the subwoofer feed becomes monophonic & plays from a single "sub" output jack.

But I have two subs that I'd like to drive from that same feed. The two hookup options available are:

1. Install a splitter at the Oppo & run dual (10-foot long) interconnects, one to each subwoofer. or

2. Run a single 10-foot wire from the Oppo to the subwoofers & install a splitter immediately before connecting the two subs.

Which option reduces the likelihood of ground-loop hum the most, if either?

Thanks - Boomzilla

Doesn't matter. Whichever is easiest and cleanest for you. Ground loop hum could be present in either scenario but unlikely

[Lonnie]

Nov 7, 2016 20:46:53 GMT -5 Boomzilla said:

If I use my Oppo's bass management, the subwoofer feed becomes monophonic & plays from a single "sub" output jack.

But I have two subs that I'd like to drive from that same feed. The two hookup options available are:

1. Install a splitter at the Oppo & run dual (10-foot long) interconnects, one to each subwoofer. or

2. Run a single 10-foot wire from the Oppo to the subwoofers & install a splitter immediately before connecting the two subs.

Which option reduces the likelihood of ground-loop hum the most, if either?

Thanks - Boomzilla

From a technical standpoint, Option 2 should offer a slight edge over the option 1. Its not likely that either one will have an audible difference, but if you look at it from an EMI or RFI standpoint, running a single long run offers the least capacitance to the line and therefore the least chance of picking up unwanted noise.

Lonnie

[Boomzilla]

Thanks - will try the single-long-wire option today.

[vneal]

Option 2 is your best choice

[AudioHTIT]

It would seem to make a recommendation we would need to know where your subwoofers are in relation to your Oppo. For instance if they were in opposite directions from the preamp then option 1 makes sense, if they're both in the same direction, then option 2. But you seem to have a plan so ... cable on.

[KeithL]

Electrically - in terms of grounding - there's not an awful lot of difference.
Minimizing the total amount of wire will lessen the chance of picking up hum - usually.

However, I would decide based on the physical wire run.
If the two subs are sitting next to each other then split it near the subs; if they're not near each other then use two runs from near the Oppo.
(You also may find that one or the other arrangement allows you to keep the interconnects further from your power cables - which is good too.)

Nov 7, 2016 20:46:53 GMT -5 Boomzilla said:

If I use my Oppo's bass management, the subwoofer feed becomes monophonic & plays from a single "sub" output jack.

But I have two subs that I'd like to drive from that same feed. The two hookup options available are:

1. Install a splitter at the Oppo & run dual (10-foot long) interconnects, one to each subwoofer. or

2. Run a single 10-foot wire from the Oppo to the subwoofers & install a splitter immediately before connecting the two subs.

Which option reduces the likelihood of ground-loop hum the most, if either?

Thanks - Boomzilla

[Boomzilla]

Both subs are stacked in a corner. Not the common location, I know, but it works WELL in my room. So single wire to the subs & split there. Will try it this afternoon.

[novisnick]

Nov 8, 2016 10:17:28 GMT -5 Boomzilla said:

Both subs are stacked in a corner. Not the common location, I know, but it works WELL in my room. So single wire to the subs & split there. Will try it this afternoon.

Yes, split just before the two subs. Works well in my system. Let us know!

Good Luck!

[yves]

Option 3, install a splitter at whatever location makes it easiest and/or cheapest in terms of routing the cable across the room and in terms of required total cable length and required total number of RCA connectors. So depending on all that, it is quite possible that the ideal way is to just hook up the splitter to one of both subs, and in fact some subs already have a built-in splitter exactly for this purpose.

That said, at 10′ distances you shouldn't have a problem with RCA cables picking up noise if you, like me, are using decent, pro grade, double shielded RCA cables. Each of the two mono RCA cables that connect my Airmotiv 5 monitors to my UMC-200 is 16′ 5″ (5 meters) long, and these cables don't pick up any noise even in the slightest. www.profigold.com/en-us/sound/55902875

[goozoo]

All the above being said, because you are using unbalanced connections and because you don't know how the house is wired, there is still a possibility that you may pick up a ground loop hum; also considering the circuitry inside the Oppo versus an XMC-1 for example. I had the same issue with very high quality cables and still had ground loop hum. If it happens, go to Sewell who makes an in-house product for the situation that will take care of it for about $30. That being said, something you may want to consider is finding a better location for the second sub and utilizing a miniDSP to EQ the differences while still running a summed mono signal. This is what I did; and it worked out so good that I added a third sub as well. Good luck.

[hosko]

Nov 8, 2016 11:13:14 GMT -5 yves said:

That said, at 10′ distances you shouldn't have a problem with RCA cables picking up noise if you, like me, are using decent, pro grade, double shielded RCA cables. Each of the two mono RCA cables that connect my Airmotiv 5 monitors to my UMC-200 is 16′ 5″ (5 meters) long, and these cables don't pick up any noise even in the slightest.

Pro grade is a marketing term, very few professional setups would use RCA and when used it would be a short run to a DI box and converted to balanced.

[yves]

Nov 8, 2016 16:45:31 GMT -5 hosko said:

Nov 8, 2016 11:13:14 GMT -5 yves said:

That said, at 10′ distances you shouldn't have a problem with RCA cables picking up noise if you, like me, are using decent, pro grade, double shielded RCA cables. Each of the two mono RCA cables that connect my Airmotiv 5 monitors to my UMC-200 is 16′ 5″ (5 meters) long, and these cables don't pick up any noise even in the slightest.

Pro grade is a marketing term,

To me it means very concise technicalities, i.e. quality materials like a robust and therefore thick enough PVC jacket, die cast metal components, hard gold plated and silver soldered contacts, and high purity oxygen free copper conductors. So no prestige branding or price premiums for little to no extra quality.

[Boomzilla]

The "one cable to rule them all" theory has worked and without any problems at all. So - single cable from Oppo sub output to the subs - splitter at the subs - no hum - no hiss - no noise at all.

Thanks for the suggestions, amigos!

Boomzilla