Axiom Home Page Forums General Discussion Home Theater subwoofer input?

In another thread Ian recommended using 2 EP-600's for the stereo setup that i am wanting..

For my processor, to get the full frequency range 20khz-20hz or so to the L/R output, i have to turn the subwoofer off.

My question is.. Where does the output that the receivers/processors output on the subwoofer channel come from? is it basically a lowpass from the L/R channels?

on a 5.1 dvd/blue ray, is the "sub channel" a separate input signal?

The reason for my question... if i do a L/R 600 then there is no need for a "dedicated" sub.. AKA EP-800...


Johnk, i am guessing you will know the answer to this?

Dak, the sub out on a receiver/processor usually is derived from two sources: the bass frequencies from any speaker channels set "small"(typically below 80Hz); the LFE(low frequency effects)occasionally present in the .1 channel in 5.1 or higher movie source material. This is all low-passed to the sub.

I'd like to try to answer more fully, but I'm puzzled by a couple points: what is the feature of your processor that somehow relates turning off the subwoofer to the frequency range in the regular L/R outputs? Also, I don't follow what you mean in the "L/R 600" vs "dedicated EP-800" sentence.

for the processor pass the entire signal to the L/R channels, the Sub has to be turned to "off" and the L/R channels selected to "large". If the sub is turned to "on" then you HAVE to select a crossover frequency even if the L/R is selected to "large". essentially only sending high-pass frequencies to the L/R channels, and lowpass frequencies to the sub.

Ian reccomended that i set up a 600, next to each M-60. to get the "full range stereo" this was in the tread "if axiom made" i think, i don't remember exact title... i was asking for a larger L/R option with a built in woofer, similar to the Wilson design.. like this with a 10" woofer in the bottom cabnet.



Ian recommended i use a pair of EP-600's as stereo subs with the same signal as the L/R speaker.


So it would be L M60+(Ep-600)/R M60+(EP-600)

or L M60+(EP-6000/ R M60+(EP-600) + EP-800


However, i was not sure if movies, had a dedicated "sub" channel being the .1 channel, that provided a separate signal to the receiver to output on the "subwoofer output" or if the receivers and such were just using a lowpass filter from the L/R ect input's to provide a signal to the subwoofer output.

I hope i made my question and intention clearer.. kind of a pain, when you know what you want to ask... But it doesn't all "make it's way to paper" as it were....

I may call the manufacture on monday to see if there is an "Advanced" setting that i did not notice in the instruction manual..

John, i think i misread the instruction manual..

"FULL RANGE sends 20Hz to 20KHz signals to the loudspeaker. LIMITED
sends information from the crossover frequency (see below) to
20KHz to the loudspeaker. The frequencies below the crossover frequency are sent to the subwoofer if present; otherwise, these low frequencies are sent to the full range loudspeakers in the system"


i scanned over the instruction manual, to try and figure out were i got the idea that the subwoofer needed to be "off" to get 20khz-20hz to the L/R output..

Okay, if this refers to the "Ivan" post(where I later kidded you about using a Russian designer, i.e., "Ivan", but you didn't see the humor), it appears that Ian was just saying to use two EP 800s with two M80s, and wasn't specifically suggesting that the EP800s be given separate "stereo" signals.

If you connect one sub with each M60 using speaker wire to the high level inputs of the sub(from the main amplifier terminals), the M60s would have to run full-range with no crossover and the EP600s would receive the full range of all the signals sent to the M60s, but the sub's internal low-pass filter(presumably set very low, probably 40Hz)would limit its response. The receiver/processor setting would be, as you say, "No" sub so that everything went out the main L/R terminals.

Yes, the .1 channel in movies is entirely separate and it's usually intended to be sent to the sub, but if the sub is shown as "No", it has to instead be sent to the mains out the regular L/R outputs.

Yup, you found the thread John



I would have to mess around with the cross over setting on the Subs, i think 40hz would be kind of low, i think i might start out at 80hz.. I was also thinking about getting an outboard cross over.

i was thinking about getting one of these, since it can separate the highpass signal and the low pass and output the two on different assignable outputs.
http://www.ashly.com/protea3.6sp.html

This way i can separate the high pass and low pass from the m-60's and the 600's before the signal gets to the respective amps..

I use an old Outlaw ICBM for this. Works great. They don't make them anymore, unfortunately.

Back several months ago, Outlaw announced a new updated 7.2 version of the ICBM-1, I believe, of course, it was announced as the ICBM-2, however, it has yet to see the light of day.

Incidentally, I have an ICBM-1 sitting in my basement, unused.

dakkon,

I just thought I would add some clarity to my earlier comments in the other thread. Though you can run a pair of subs with designated Right and Left channel information (use the high level inputs connected the right and left speaker wires with the subwoofer x-overs set to 40 Hz) I am not sure you would really want to do this. Even if the information below 80 Hz was separated on the source material, which it rarely is, you would still not be able to perceive its source location in the room. For the best bass in your room you will almost for sure find that the best location for the two subwoofers is not adjacent to the right and left main speakers. The advantage of the two subwoofers is that you get to put them anywhere in your room where they will give you the best bass at your various listening positions. And with two subs, as opposed to one, you will be able to get more listening positions to have good bass. This is a pretty big advantage over the design you have pictured where the “subwoofers” are built into the front main speakers. As for where to set the x-over point, assuming you are using a processor with bass management and it appears you are, then that would be best decided with experimentation in your room. I think JohnK has covered the answer to your original question pretty thoroughly, though I am not completely sure if you are looking to set up a stereo only system or a multi-channel system that you will use as stereo when the source is recorded that way. Either way it would not affect the sub selection and placement. I hope this helps with your quest for the best performance; and I would make those two subs EP800s.

The only problem with that Ian, is i already own 1 600, so i would only have to buy 1 600, instead of 2 800's..


The goal was for stereo sources, and also be able to use it for multi channel.
The the dual sub idea, was primarily for stereo, right now i am using 2JBL 8" woofers in this configuration, per your idea Ian.

The processor I am currently using is a Krell HTS 7.1, and the cross over I was planning on using was the ashly Protea 3.6SP 3x6 Speaker Processor, it can separate the source material and send different frequency ranges to different outputs. So I could have the same source material supplied to 1 highpass output, and 1 lowpass output. All on balanced cables. Thus getting the "same" signal to the M60, and 600 supplied to their corresponding frequency ranges.


Alex