# Sub wiring - Line in 0r speaker



## Steve Williamson (May 11, 2006)

My current set up is 1 x Richter Krakatoa 100W RMS sub with subwoofer pre-out from Pioneer VSX D814 receiver.

I just read about wiring subs with two cables coming from main speakers out of receiver with one cable going to main speakers and one going to subs speaker in, can someone clarify this for me.

I thought if you used speaker out then the sub didn't use its amp, or is it just bypassing the receivers crossover and the sub will still use its internal amp?

I'm confused :blush: 

I need to know for the next generation HT.


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## Sonnie (Apr 11, 2006)

My suggestion would be to keep it as you have it. Sub pre-out from receiver to line level input on sub amp. I think the only reason those speaker level inputs exist is if you don't have a sub pre-out... (I said I think, so don't hold me to it). Surely some others will have some input on this.


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## Fincave (Apr 20, 2006)

Not sure will this help so don't shoot me. My sub has both a low level input and a high level input connection option. Low level is the regular connection to the sub output of a receiver, processor. Acording to the manual using the high level input connection (which sounds like what you are referring to) " advantage of this method is that the sub receives exactly the same signal as being supplied to the main speakers, this means that the character and tonal balance of the bass from the main speakers is carried though to the sub bass". The manual also meantions " high and low level connections can be used at the same time if required, this has the advantage of being able to connect up a Hi-Fi and AV system simultaneously."  Hope this helps!!


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## Steve Williamson (May 11, 2006)

I think Fincave hit the nail on the head with


> advantage of this method is that the sub receives exactly the same signal as being supplied to the main speakers, this means that the character and tonal balance of the bass from the main speakers is carried though to the sub bass


This way, the receiver does not mess with any signals and the amps crossover will smooth the transition from mains to sub.

However, does the subs internal amplifier still power the driver with high level input?


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## Fincave (Apr 20, 2006)

On MY sub there is a separate gain control for both the low level and high level input connection option so I would presume that the subs amplifier is still powering the driver! Please note: I am only referring to my sub and the manual that came with it!


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## kingkip (Apr 20, 2006)

The problem with that method is that now you are relying on the xover of the sub to pull out the low freqs which will then be sent to the spooks. How good is that xover? IMO one more link in the chain to degrade signal quality. Not to mention that your receiver will have to work harder to send the LF stuff to your sub/speakers via it's own amp rather than completely utilizing the sub's amp. Generally you will get better sound by being less demanding on your amplification section, especially on a relatively lower powered receiver. You also need more speaker wire, not such a big deal, but... To top it all off, if you run it that way you are only using the bass sent to the front stereo pair. The center and surround speakers still have to produce a full range. There usually isn't a ton of LFE in the surrounds but there is a good amound in the center.

With the line in the receiver is splitting the signal for you and theoretically doing no harm. The same signal is still sent to both sub and speaks, just part goes one way and part the other. Also it is usually easier to set the xover on the receiver to match the speakers capabilities rather than the subs xover.

Either way the sub's amp is still being utilized. You are just asking your receiver to pull double duty and once again IMO degrading the sound quality the receiver is capable of.


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## kingkip (Apr 20, 2006)

Steve Williamson said:


> This way, the receiver does not mess with any signals and the amps crossover will smooth the transition from mains to sub.



Also remeber that the receiver's job is to mess with the signal. They usually do a pretty good job.:T


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## Brian Bunge (Apr 21, 2006)

Unless you have something like the REL subs (which is what it sounds like Fincave might have) then you really should use the low level input(s) on the subwoofer. The sub's amp is being utilized regardless of which inputs you are using but you need to use the receiver's internal crossover so that your speakers are not having to reproduce the bass frequencies that the sub is already reproducing. At least that is what is normally the best route to take for a multi-channel system. This is a more efficient use of amplifier power for your speakers and therefore keeps the receiver's amps from having to work as hard.


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## Exocer (Apr 19, 2006)

I agree with everything mentioned above. Before owning a receiver with a dedicated LFE pre-out I found myself using the High level inputs on my Velodyne. It worked alright until I found out it didnt have the 80hz highlevel crossover I thought it had. This meant that the speakers I connected to the sub wouldn't be crossed over at all, since my main 2 channel stereo receiver at the time had no type of bass managment. Stick with using the LFE pre-out.


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## Fincave (Apr 20, 2006)

Brian Bunge said:


> Unless you have something like the REL subs (which is what it sounds like Fincave might have)


 Maybe I should have mentioned my sub, it is a BK Electronics Monolith, if I remember correctly they supply parts to REL. Not trying to hijack this thread but what is the best connection type if one has a REL/BK Electronics sub. I just use the low level input connection though still have the Neutrik connector packed away somewhere. 

My apologies to Steve Williamson for using this thread!


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## Steve Williamson (May 11, 2006)

No worries, it will probably answer a question I have in 6 months anyway. Also. looking at the BFD, if I go that route, it will need the RCA line in connectors won't it?


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## Brian Bunge (Apr 21, 2006)

REL is just offering connection flexibility so that their subs could be connected to both multi-channel HT and audiophile 2-channel pre amps simultaneously. I believe ACI offers similar connectivity with their subs and are priced much better, IMHO.

If you have a single receiver/pre/pro in a HT type setup then using the LFE output into the line level inputs on the sub makes the most sense.


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## Brian Bunge (Apr 21, 2006)

Steve,

Yes, you will need to use the LFE output from your receiver into the BFD and then the output from the BFD into the line in on your sub.


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## Sonnie (Apr 11, 2006)

You'll probably want to have some cables made for you on that BFD connection. It actually requires 1/4". I had a RCA to 1/4" made from my sub pre-out to the BFD input and a 1/4" to dual RCAs from my BFD output to two sub inputs. Of course you can also use the 1/4" adapters from Radio Shack... I used those until one of them broke on me from the weight of the cable hanging (true story). Well it didn't break off but it broke and was just barely hangin' on. I decided then it was time to get some good cables built... which I had been threatening to do anyway.


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## Brian Bunge (Apr 21, 2006)

Oops! Sonnie is right. I forgot to mention that you'll need 1/4" plugs on one end of the cables going into the BFD. When I had mine I did use the 1/4" adapters but will rectify that when I get a new one.


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## Exocer (Apr 19, 2006)

My local DJ audio store had the Rca->1/4" cables sold in pairs for $9.99. I also recommend using a Y-splitter if your amp has two inputs. http://www.topdjgear.com/hohedu1to1ca1.html
You'll only need a pair. If you do get cables made you'll have no need for the Y-splitter.


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## Brian Bunge (Apr 21, 2006)

There's really no need to use a y-splitter unless you need a stronger input signal into your subwoofer.


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## lcaillo (May 2, 2006)

Fincave said:


> Not sure will this help so don't shoot me. My sub has both a low level input and a high level input connection option. Low level is the regular connection to the sub output of a receiver, processor. Acording to the manual using the high level input connection (which sounds like what you are referring to) " advantage of this method is that the sub receives exactly the same signal as being supplied to the main speakers, this means that the character and tonal balance of the bass from the main speakers is carried though to the sub bass". The manual also meantions " high and low level connections can be used at the same time if required, this has the advantage of being able to connect up a Hi-Fi and AV system simultaneously." Hope this helps!!


Using the speaker connection means that the sub receives exactly the same distortion as the main speakers, too. Using the speaker level inputs is typically a bad idea for several reasons. First, as I said, any distortion in the amp stage is added. Second, you have to run the mains full range and you are adding the bass from the sub and the mains, making placement even more critical. This also causes the amp for the mains to have to work much harder producing bass that it would not have to if you use the LFE output and send the bass only to the sub. I also makes crossover areas harder to tune and deal with. Third, you are having to take the speaker level signal back down to pre level so you are adding signal path that may or may not be particualrly clean.

You might, in some limited cases, be able to break a ground loop that cannot be dealt with without isolation by using speaker level inputs, but you can usually use better methods for this kind of problem.


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## GregBe (Apr 20, 2006)

speaker level connection is viable if you have small mains, and you don't have adaquate bass management in your receiver. Since that is not an issue with just about all modern receivers, I would always use the line level connection.


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## Chrisbee (Apr 20, 2006)

I ran my SVS 16-46 cylinder with high level connections and 40Hz floorstanders running full range for a couple of years. 

I had no pre-out on my stereo pre-power at the time. This worked so well I needed a 60Hz crossover point to get a nice flat response through the crossover point. 

Actually it was a very nice, ski jump house curve up to 15Hz. But we wont dwell on that. :T

I wouldn't use the built-in crossover in a sub plate amp to feed the speakers.

Of course the plate amp in a subwoofer powers the sub driver. 

The plate amp just has a very high impedance high level input to protect the stereo amp from the effects of a low (parallel) impedance.

It has been said that you don't even need proper speaker cable to feed the sub on high level connections. Ordinary twin lighting flex will do just as well.


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## xcapri79 (Jun 7, 2008)

I think using the speaker level inputs can allow small subs to be used to supplement the bass on the surround speakers. I use two Polk PSW505 subwoofers with the Polk RTi8's as my surrounds and they certainly do the job. 

I just copied the idea Polk and other manufacturers had with adding subwoofers to their speakers such as the RTi100 and LSi25. Up front I use a KEF PSW2150 subwoofer with a LFE input. 

I used to use the speaker level inputs when my previous receiver didn't have a subwoofer preamp output.


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## Usher (Aug 18, 2008)

Hello from Finland!

Continuing this thread.

I have Monolith sub and currently using both inputs at the same time, because it's the only way to accoplish what I want, or is it?

I have Yamaha RX-V 3800 receiver, and using that also for 2-channel listening. I prefer using amps "pure direct" feature in 2-channel, which gives best and purest signal. So if I understood right, when "pure direct" is on, then amps crossover won't work, and it does not send sub-signals to sub-out. So if I want to use sub in 2-channel listening I have to use high-level input and sub's crossover.

I would like to use only low-level input and just the recievers crossover, but I think it's not possible, when using "pure direct" in 2-channel. Am I right or is there any other possibilities to do that?

Luckily monolith sub has level control for both high and low inputs, so I can keep my sub "hot" when watching movies. But still have to use just sub's crossover.

Am I doing this right and only way, or is there a simpler solution?

Thanks for any help.

MV


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## salvasol (Oct 31, 2006)

Usher said:


> ... So if I understood right, when "pure direct" is on, then amps crossover won't work, and it does not send sub-signals to sub-out.


No, what the receiver does in "Pure Direct Mode" is to turn off all digital signal processing ... so it will send what is in the disc untoched :yes:.

What you have to do is on the AVR set up ... just tell the receiver that there's a Sub connected.

I think most sub manual advise agains the use of both terminals at the same time (speaker and line in) :yes:

But I could be wrong ... :huh:


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