Sub wiring help, high level speaker terminal to RCA line level Sub inputs

@jtcf I just don’t see the reasoning in using a Y adapter if I could just use a straight cable from the source to the Sub. Is the adapter going to give me a better connection or signal in some way than a straight cable? I would still need to spend more because of the cost of the adapter and also an extra set of cables as well. And I figure it could potentially introduce more adapter related issues unnecessarily.

I’ve done some more reading and found using an XLR to RCA cable is a bad idea. Mainly because to make the cable the XLR (-) lead is shorted to the ground lead on the RCA side, which could cause feedback issues and potential damage, so those options are out.
https://forum.audiogon.com/discussions/cd-player-xlr-output-buzzing

So my options are then what yogiboy and jtcf suggested to use an RCA Y-splitter, or my original though of using a speaker terminal to RCA cable.

@millercarbon Thanks that's a lot of good info, I'll read up on it more closely, seems like real easy job. I ended up buying the Y-splitter to see how that works out in the mean time. I could already use some cheap stock rca's I have laying around to try out the resistors.

@lalitk It’s just a PITA to return plus having to pay for return shipping for a 50lb package. And Rhythmic doesn’t have another similarly priced option. If I end up returning it I’ll get an SVS SB1000 which was my 2nd choice. It’s really annoying because even though on Rhythmic’s website it doesn’t explicitly say the L12 has high level speaker inputs, they have reference pictures on the L12 page that shows a back with the speaker inputs, which I see now is not actually an L12 at all. So while I’m sure it’s not done on purpose it is unintentionally deceiving of what you’re actually getting. If I had double checked before putting in my order I wouldn’t have bought it, but now since I waited 2 months for it and I do think it has the best specs and features I would like to try and get it to work as it should.

@millercarbon I see, the one thing is I just personally hate using any kind of adapters, converters, etc.. on my equipment. Even though it’s cheap and should work with no issues it’ll always be nagging at me that it’s not connected in an optimal fashion. If it were just a temp solution to get the job done I would do it, but I just feel if I’m paying $500+ I want it to work as intended with no additional trickery.

One question is if the input to the Sub is only technically used as a signal, not carrying any loads, wouldn’t I simply be able to use a straight cable from my speaker terminals with RCA’s plugs on the other end into the Sub? This would provide the same function as that converter without adding in extra resistors?

At least they have a 45 day return policy if I can't find a solution I'm happy with.

I completely agree, that's the main reason I didn't want to go with any kind of adapter/splitter and just figure out some way to get a direct connection. It bugs me to spend money on better speaker cables and then terminate them with a Y-splitter.

Just for discussion using the resistors, is it possible to get unwanted feedback back into the pre-amp that can cause some other kind of distortion?

@almarg I understand I meant terminate as just the end of the cable. You're right I miss-spoke saying pre-amp, I meant power amp. Thanks for the explanation!

Wanted to post a follow up. I've spoken to all 3 companies in the mix, Rythmic, Cambridge Audio, and Schiit, they all said to use the RCA line out with a Y splitter. They said the speaker post connection would at best sound the same, but have the side affect of potential distortion so there's no real point in using that connection unless the sub was made to use them.

I tried using the amps speaker post output anyway, the volume levels were not incredibly different, they were about 25% louder than the RCA line out. In the end I couldn't really notice any difference in sound quality between either one when volume matched. So I'm going to stick with the RCA line outs using a Y split for peace of mind.

Now I have one last question, I've been using BJC LC-1 cables to my power amp, but for now only had left over cheapo component video cables I was testing to the subwoofer. I would like to get RCA's that are Y split themselves to not have to use an added Y adapter. However BJC cannot make the LC-1 cables in Y configurations, only their MSA-1 cables which don't have the same gauge, shielding, etc..

So I'm not sure if it would be best now to use 2 higher quality LC-1 cables attached to the separate Y-adapter, or use 2 lesser quality MSA-1 cables already Y split and eliminate the use of the adapter.

Or is there another cable company that can make better quality custom Y cables for the same price as BJC?

@millercarbon I see what you mean. One thing is why would any possible distortion be present through the pre-outs but not through the speaker outs? I don’t think the power amp is doing anything to make the signal out of the pre-amp cleaner. I figure it’s just amplifying, which whether done through the RCA outs, or eventually through the power amp and speaker terminals, it’ll still be there. Unless the argument is based on the the Y-adapter itself causing the distortion, not the pre-out signal.

One other thing that I was thinking about is the effect on the audio signal after being amplified multiple times over if using the Speaker level outputs. So the pre-amp is slightly amplifying the signal, which is then fed to a power amp that is again amplifying the signal even more, which then in this case would be sent to a 3rd amplifier which would be amplifying a signal that had to be lowered by resistors in between, before finally reaching the Subwoofer itself.

Just in a logical sense to me going though that cycle seems like it has the potential to introduce more distortion to the sound than going one straight shot to the power amp.