Hifi-Amp to Subwoofer Connection, what cable, what input?

[walvis]

I do have an Yamaha AS-500 amp connected to two sets of Monitor Audio BX2 speakers and recently added an Monitor Audio BXW10 subwoofer since my room does not really seem to bring out the lower frequencies. Richer Sounds sold me a 1-2-1 Cambrigde Audio sub-cable. While there is only one out option on the Yamaha amp, I noticed two input options on the MA BXW10. One is a classic red/white R/L input and the other one is labelled LFE. According to the manual, the LFE is designed for connecting the sub to an digital AV amp, which clearly the AS-500 is not.

So I have tried out connecting the 1-2-1 cable to both the R and L ins as well as into the LFE. What I noticed is that when being connected to LFE, the bass volume is significantly higher. Since I could not found any information what the right connection is, I am now slighly confused. Am I supposed to use the LFE, or one of the R/L inputs or even another cable with a 1-2-2 configuration to connect to both the R/L input.

Apologies, first sub ever and also not an AV expert... so please excuse the probably stupid question.

 

[tomlinscote]

I would have thought that from a hifi amp you should simply connect the amp's pre out (volume controlled) output to the L/R inputs of the sub using a standard phono cable, that is what I do and the sound is fine.

Tommo

 

[AnotherJoe]

Connect to the LFE on the sub if you want to control the crossover level via the amp.

If you want to control the crossover using the control on the sub, then just connect the amp to the L input

In either case the crossover range for a bookshelf speaker is 50-90hz depending on your listening preference.

 

[MattSPL]

Your lack of bass might be due to phase cancellations in your room. Running 2 sets of speakers is not usually done in a 2ch home setup.
Have you also checked the + & - connections all match up at speakers and amp?

As for the sub, does it have a single RCA subwoofer output, so for example you can only connect a red or white phono cable, not both? If this is the case, connect the single cable from the amps sub output into the lfe on the sub.

 

[walvis]

On the phase cancellation. The room is split by french doors and I tend to only use one pair at the same time, depending where I/we are listening, so that should not be the issue. It's more down to the architectural specs as I have used the same setup in my old flat with ore furniture etc. resulting in a better bass response.

On your recommendation to connect to LFE and control the crossover from the amp, I though (and I might be wrong), the AS 500 as a stereo amp is not able to control crossovers and therefore the LFE in would not enable me to do any adjustments. Not sure if this is correct.

Secondly, if I connect to RCA, is it ok to just use a mono lead to either the L or R in or should I buy an subwoofer Y cable so that I can exit from the single "Sub Out" on the Amp to the RCA R/L in, something like that: http://www.amazon.co.uk/Oehlbach-Subwoofer-Y-Cable-Jack-Black/dp/B00007ELXI/ref=sr_1_3?ie=UTF8&qid=1364078440&sr=8-3

As mentioned, when putting the mono lead into either the R or L in, I can control crossover and phase, but the volume is generally lower, since the double room is rather large, the LFE volume seems quite attractive...

 

[MattSPL]

Ok, sounds like the 2 sets of speakers are fine.

I didnt realise the subs crossover was out of circuit when you connect into its LFE. In that case, connecting to the left or right input is the way to go. Using a Y splitter should solve your low volume issue as you will be sending twice the signal into the sub. I remember using a Rel sub before with a single RCA cable and the volume was very low.

 

[walvis]

Sounds like a y splitter is the answer here... stumbled about this one http://www.superfi.co.uk/p-3969-qed-performance-ysw-subwoofer-interconnect-y-adaptor.aspx - so will probably continue to use LFE as an interim solution until the y splitter arrives as the rca volume is simply to low for the room in the current setup. Should have an old, low quality y cable flying around somewhere. Will dig that out tomorrow and test how the volume is affected, but sounds good....

Thanks for all your help...

 

[MattSPL]

Let us know how you get on

 

[walvis]

Will certainly do...

 

[walvis]

Since I promised an update, Monitor Audio Support replied, and apparently the LFE connections is the right one:

"I have just looked at the user manual for your amp (link below) and it does have a sub-woofer output on it. So despite not being an AV amp, it does have a dedicated sub woofer output channel which means you have got the correct cable and that it should be connected to the LFE Input on the sub woofer.

Link: http://download.yamaha.com/api/asset/file/?language=en&site=uk.yamaha.com&asset_id=54754"

 

[MattSPL]

Thanks for the update. The answer you got doesn't make sense if you can't control the subs crossover. They obviously didn't realise that.

 

[nopiano]

i agree with MattSPL. They didn't do a very good job of reading both manuals, which I have just done.

Yes, the sub output on your Yamaha only outputs below 90Hz, so that is the correct output, but you presumably have no processor with which to make adjustments because it isn't an AV amp. So you need to put the cable in the left or right inputs (doesn't matter which) as that way you can adjust the sub's volume and crossover to match your speakers per the table. As they say, you can tweak it a bit either way.

Personally, I suggest starting at zero volume on the sub, turn it up until it is noticeable, then back it off a shade. Then listen from your normal seat rather than the floor! Then adjust slightly up or down, so that you are not aware of the sub unless you switch it off. Remember it is for music not atomic bomb sound effects!

 

[walvis]

Ok, seems you guys have been right, just got a reply from Yamaha confirming that I need to use one of the R/L inputs. I actually bought a Y splitter and now seem to get a decent volume out of the R/L ins....

"From the description of your set up you would need to use either of the L or R inputs on the subwoofer as your A-S500 being a hi-fi amplifier has no crossover adjustment (but please feel free to check this with the manufacturer of your subwoofer for clarification when the subwoofer is used with a hifi amplifier as opposed to a AVR) as neither the L or R sockets are marked as a mono input we would think either socket would be ok ( but again we would recommend to check with the manufacturer of the sub).

One other point we would recommend to test would be the phase of the sub, as the bass that you hear in your listening position can mean you could be in a peak or a trough of the bass signal, a quick test would be to change the phase on the sub to see if the bass signal in your listening position is increased or decreased and which do you prefer ?

Hope this helps and if you have any further questions or quereis, please do not hesitate to ask.

Many thanks

Yamaha Technical A/V

A/V & Hi-fi Technical Support Team
Yamaha Music Europe GmbH (UK)"

 

[MattSPL]

Glad you got it sorted

 

[nopiano]

Glad you got it sorted

Here, here! Or is that hear, hear?

Disappointed at the duff reply from MA though.