# LFE/ Sub out jack / 2 Channel



## airpiratehkg (May 27, 2008)

Need your thoughts as it applies to using the sub out jack on my RX-V2600. 
I am noticing a huge difference in sound quality when listening to 2 channel audio (CD's) over the following setup (note this is in reference to 2 channel stereo listening not movies):

Setup 1: 
=>Deftech Mythos 1 mains x 2 connected directly to receiver in the usual fasion.
=>Deftech Supercube 1 sub connected to sub output jack on receiver (single cable from receiver to LFE hookup on sub).
=>Receiver: Mains set to "small" bass output to "sub" xover at 80Hz

Setup 2:
=> Main L/R channel connected to "High Level" inputs on the Supercube I
=> Mythos 1's connected directly to the "High Level" outputs of the SuperCube I
=> Receiver: maines set to "large" bass output to "main" sub xover at 80Hz (on the sub side not receiver)

Phase and sub gain are correct and identical in both setups.

Here's what I am finding. There is a very obvious difference in sound that anyone short of a deaf person would notice immediately.

Setup 1: Sounds thin like there is a section of mid / mid bass missing. This is really obvious when listening to Beatles / Stones. Sounds like - made me long for a set of true full range speakers again and want to trash this sub setup. 
Setup 2: Polar opposite of setup 1. Truly sounds like a pair of good old full range speakers. Really and amazing difference!

So my question is this: Why the difference? i would have though that setup 1 and 2 would have identical sound. Only differences being 1 cable vs 2 to the sub and using the xover on the receiver vs the sub. Is the sub output jack on the Yamaha built around movie soundtracks and possible throwing out a range of frequencies not normally found in digital movie tracks? I noticed the folks at REL in thier user manulas (makers of high end subs) recommend that us 2 channel buffs hookup via high level rather than sub output jacks.

Anyone else experienced this.. And please folks phase and all that jazz are set correct.


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## brucek (Apr 11, 2006)

> Why the difference?


Probably because the receiver has the typical bass management crossover setup of a 2nd order (12db/octave) high pass to the mains and a 4th order (24dB/octave) low pass to the sub.

A quick look at your sub on-line and I see these specs:

_High Level High Pass Crossover :Non Variable *6 dB/octave* @ 80 Hz: Available only with high level inputs and outputs
Low Pass Crossover% :24 dB/octave, continuously variable from 40 Hz – 150 Hz:_

See the difference. The mains only have a 1st order filter on them and will therefore contribute a lot more bass to the mix.

Some may like it, some may not.

brucek


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## airpiratehkg (May 27, 2008)

Burcek that makes perfect sense! Thanks for solving my mystery.. Learned something new.
Thanks


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