Axiom Home Page Forums General Discussion Advice from Axiom Owners Sub Hookups

Hey,
I'm just wondering if there are any differences between using a low level LFE connection versus a high level connection to a sub from your receiver? I'm aware that the LFE connection puts your receiver in control of crossover, while the high level connection allows your sub to control that. Is one of these prefered over the other to achieve higher quality sound, or is it simply presonal preference?

Thanks

What receiver are you talking about? My Pioneer Elite (as many others I would suspect) have the sub-out port(s) on the back, and internally to the receiver, you can set the crossover to whatever you want, including full range. Not that you would want to. The standard seems to be 80Hz, but I guess you could play around with it, or if you think that the sub has a better crossover or something.

If the equipment is doing its job, then it shouldn't matter which part handles the crossover. I guess if I was the type of person that liked to mess around with the crossover on a regular basis, I would set it higher on the receiver, and then let the sub handle the crossover. That is because in order to change it on the receiver, I have to go through a couple of menu screens, but on the sub itself, I just turn an adjustment knob a little bit.

That is the only reason that I can think of, but I really don't mess with it once it is set. Others may have different opinions.

I'm not referring to a specific receiver, just in general. If I understand correctly, there are two ways to get a signal to the sub:

Option 1: You can run your front channels through your sub, which then extracts the low frequencies according to the crossover you set on the sub. This means you don't use the preout on the receiver and the sub controls the crossover.

Option 2: Use the sub preout on the receiver and run the front channels directly to the front speakers. This way the sub gets a dedicated channel from the receiver and the receiver now controls what frequency range is sent to the sub and front speakers.

The reason I'm asking is because my cable run is fairly long to the sub (~20-30 ft since the cables will go up to the ceiling, across to just above the sub, then down to the floor where the sub is). Now if I use Option 1, I only need two wires for the front channels to go to the sub, and since the fronts are on either side of the sub, not much extra cable is needed to carry the signal from the sub to the fronts. If I go with option 2, I need to have the 2 wires for the front channels as well as a dedicated LFE cable for the sub going the same distance. So it's a little extra cost to cable it for option 2, but if the sound quality is increased, I will go this route.

Does that make sense? The question is simply "Which sounds better, Option 1 or 2?"

Unless you're talking about stereo only listening, using option 2 is the only way to go. If you don't you don't get the dedicated LFE channel, or anything from any other channels that is being directed to the sub by the crossover in the receiver. (Same deal with using the sub's crossover instead of the receiver).

Also, on my sub (in my opinion), I found the line level inputs performed better.

Frankly, I'd rather run a single cable to the sub than (min) 4 separate wires to the sub, and then 2 wires to the fronts.

Well, yeah, I guess... but... still seems a lot more complicated than it's worth.

>>What if I set the receiver so that there is no sub and put the front channels as large, shouldn't that redirect the bass to the front speakers which could then be extracted by the sub?

You would expect this, but not all receivers work this way. Yamahas definitely do, HKs seem not to, and I think the rest are split about 50/50.

Jason, your understanding may not be entirely correct. When a coaxial cable is used from the sub output on the receiver, the receiver can handle both the high frequency rolloff of the sub and also the low frequency rolloff of the speakers quite accurately. Typically the sub is rolled off at 24dB/octave above the selected frequency(e.g. 80Hz)and the speakers are rolled off at 12dB/octave below that same frequency(with an accuracy of about 1-2Hz). When a high level connection is made with speaker wire the receiver does no bass management. The internal crossover on the sub only rolls off the sub, it doesn't roll off the speakers(even if the speakers are connected through the sub) as the receiver bass management does. Also, the markings on the sub's internal crossover control are typically far less accurate than the setting on the receiver. Some subs do have a separate fixed filter around 100Hz on their speaker out connections, but otherwise the speakers would run full-range and not be relieved of some of the low bass burden.

In short, for more accurate bass management which will affect both the speakers and sub use the line level coaxial cable connection and set the speakers small.

Thanks for the repies. I appreciate the detailed explaination John, that is exactly what I was looking for. I will be ordering the extra coax cable for sure. The receiver that I will be using, which I just picked up today for $555 CDN, is the Yamaha HTR5960. Sounds like a good one so I'll see how it works when my Axioms get here in about 4 weeks, hopefully less . I will be making my order for them tomorrow. Does anyone know any secrets for making 4 weeks go by faster?

See the "cocktails" thread. That seems to help.

We can tell you that "looking out the front window" does *not* help.