High-Level Sub Input Connections Question

msg

You guys running high-level sub inputs...

With RCA connections to a sub with LR inputs, the convention if only using a single cable run is to run a splitter at the sub input to provide signal to both inputs. It results in a higher input signal so you don't have to turn up the sub volume as much.

With the high-level input method, do any of you run a jumper between the LR high-level input terminals at the sub when only using one sub and one cable run? It seems like I have to turn my sub's volume up higher than I should.

SeleniumFalcon

That would not be a good idea, you would be, in effect, shorting the left and right speaker outputs together if you used jumpers.

pitdogg2

Just run two speaker cables to the speaker cable inputs and then 2 speaker cables out to your speakers. I used that method for long time. You then use the subs XO for the signals sent out to the speakers.

I think this is what you're asking if I understood the question.

Ken is on point with the short, magic smoke will be let out....

msg

Okay, yes, this is what I was asking.
I didn't really think that through all the way before posting. I'm probably missing something, but I still don't see how it can short the left and right speaker outputs. It would be one speaker cable from one output channel from an integrated. The idea of the jumpers at the sub would be to input the same channel signal into both inputs of the sub, like the RCA method does.

Ivan, I see what you're saying, yes. I always wondered how this worked though, if you combine LR speaker outputs at a sub. Is the assumption here that the low frequencies are the same on both channels? If they are not, wouldn't this cause congestion in the sub, trying to play two different signals at the same time?

Why do people run stereo subs? I thought it was that bass information can be different for L & R channels.

pitdogg2

Low end should be mono. With left and right RCA inputs, I've always been led to believe you use the left for only one LFE/RCA out to the sub. At least that is how Cerwin Vega explained theirs on my CVT subs. The CVT's had LFE, RCA and high level speaker input and output.

Stereo subs can blend the room better. I ran them in front and back configuration in diagonal opposite corners. Made huge difference in the amount of quality bass.

SeleniumFalcon

"The idea of the jumpers at the sub would be to input the same channel signal into both inputs of the sub, like the RCA method does."

This would create a connection short exactly as if you took both of your speaker outputs and connected them together.

msg

Hahaha, thanks for saving me from the consequences of that little experiment, Ken.

Thanks for the supplemental suggestion, Ivan. I'll experiment with it the way you described.

GlennDog

My preamp has 1 pair of RCA outs & 1pair of XLR outs. XLRs goes to the mono blocks and both RCA outs go to the sub "Line In" jacks. There are also LFE jacks on the sub when using an AVR. There are no high level inputs (for speaker cables).

treitz3

Ivan, I believe LFE is mono. It has to be, since you are only using one cable.

Low frequencies are most definitely in stereo. I have the Rythmik F-25's hooked up in stereo (using RCA line level inputs to L&R respective subs with splitters right before hooking them up to the subs, so I can fully utilize the amps (L&R) on the subs.

Mark my words, there is a plethora of low frequency information in stereo. Especially when your subs are at the tweeter level (I have mine on stands....front firing subs with the tweeter positioned in between both the top and bottom woofers, flanking the mains). When done right? It's sublime.

Tom

msg

I thought I read that, Tom. Might even have been on one of your threads when you were first integrating an earlier set of stereo Rythmiks.

What frequency range are you talking about?

treitz3

Probably. That is about a 5 year old thread now. To answer your question, whatever frequency is on the original recording.

Tom

treitz3

It was actually 2 threads. The original one was this one - https://forum.polkaudio.com/discussion/110168/raising-sub-woofer-level/p1

When I got the Ryhtmik subs - https://forum.polkaudio.com/discussion/178729/dual-rythmik-f-25-direct-servo-subs-on-the-way/p1

All of my initial thoughts/observations are documented on these two threads. The subs still reside on the stands and are toed out just a little bit more than the mains. I have no reason or desire to change anything up with regards to the subs location(s).

I would say that the experiment was a complete success and I can no longer locate where the subs are in the room. They blend seamlessly to the mains with no discernible locationality cues. The timing issue is no more.....of course the Rhytmik subs helped immensely with that. The Tyler's were actually slow in comparison.

Tom

msg

It is/was old. I think you were playing with F12s back then.

I was meaning, is there a frequency range you've noticed before the frequency goes mono? I've seen notes about both perspectives on this.

If it's connected via high-level or RCA from a preout, I can see getting full range info and potentially lower frequency signal from the respective channel, but at what point does it become indiscernible? Still getting stereo effect at say 30Hz-40Hz and below?

treitz3

Well below that IME. I have mine hooked up on a variable loop out from the amplifier, so I am getting the full signal in stereo, 100% of the time.

It depends on the album/recording/mastering but as low as they want it to go, it will be in stereo if they put it there. BUT.....it has to be in stereo on the album. Some albums, it sounds like they blend the lowest of frequencies but other albums? Wow, is it a treat to get low frequency information presented just as good image wise/sound stage wise as one would get with the midrange, vocals or the upper frequencies.

It is just another element to enjoy in the reproductive effort. It's very hard to achieve (honestly) but when it's done and done right? Bliss.

Tom