Axiom Home Page Forums General Discussion Advice from Axiom Owners newbie needs speaker/sub advice!

First of all, here's what I'm working with....
Axiom Audio M1Ti's (front and rear)
Axiom Audio M1 Zero (centre)
Axiom Audio EP125 sub
Marantz SR5200 receiver
Panasonic DVD (RP52-K or something like that)

I have a ton of questions, I hope someone can help me out, local audio stores and previous internet searches have been foggy at best, and sometimes totally useless.

1. What is the purpose of the phase switch? I flick it and I hear no difference in sound from the sub.

2. What is the suggested setting for the audio/video switch on the sub? If I switch it to video, the bass seems to increase, which leads me to turn the volume on the sub down.

3. I was told that because my speakers are so small that I only need to use 16 gauge speaker wire, do you agree?

4. My receiver allows me to adjust the level of each channel, from -15dB to +15dB. If I set the levels at 0, I have to turn the main volume up from -75dB all the way to +2 to get a decent level of sound. By adjusting the levels up individually, am I providing more power to the channels, therefore creating more headroom and potentially improving sound quality? Or am I turning it up too much and degrading it. Likewise, by having the master volume up so high, am I possibly degrading sound quality?

Your help would be MORE than greatly appreciated. I have this strange feeling that I am not getting the most out of my home theatre.

CF, lets try: 1. The phase switch at 0 has the sub cone pushing out and pulling in at the same instant as the main speakers; at 180 it's in when the mains are out. The 180 might help in some situations due to a difference in room location between the sub and mains, but if you notice no difference leave it at 0.

2. I'm not familiar with there being such a switch on the EP125 and this may be something relatively recent that others can comment on, but I'll take a guess. There's a belief(misguided in my opinion)in some quarters that a sub should have more "oomph" for movies than music, so a switch is provided that gives an artificial boost to mid-bass frequencies. If this is the case, I'd leave the switch at "audio".

3. The size of the speakers has nothing to do with the size of the speaker wire. The primary factor is the length of the run from the receiver to the speakers. Unless you have runs longer than, say, 30 feet, regular 16 gauge lamp cord is fully adequate.

4. I'm not familiar with the 5200 and I'm not sure what +2 represents, but unless it's more than about 3/4ths up, it isn't anything unusual that needs to be changed.

I'll clean up after JohnK.

The audio/video switch indeed gives an extra boost to mid-and-low bass frequencies to give movie soundtracks more impact (when switched to video). Some people like this effect, others don't. I would suggest setting your sub gain exactly where you like it for music. If you're not getting the impact you want watching action movies, flick the switch to "video" for some added punch.

Adjusting up individual levels for each speaker should be done with caution. Remember, for a +3 dB difference, the receiver will need to send double the power to that channel. For example, setting the center channel or surrounds at +3 dB can cause your receiver to clip if you turn up the gain so that the mains are loud enough.

Make sure that all of your speakers are set to "small" in the receiver setup menu. This will route bass information to the sub which powers itself. The Marantz should have no problem driving the small speakers in your setup to an adequate listening volume, as long as your room isn't too big.

Thank you very much both of you for your help, it's greatly appreciated. Would you suggest that I leave all the channels at zero and rather than increasing levels for quieter channels, I reduce the levels of the channels that are louder to properly match all the channels? The surrounds I find I have to turn down, it's only the left and right front speakers that I have to compensate for. Also, the runs of speaker wire to the rear channels are over 30 feet, what gauge wire would you suggest for those channels? Finally, what' the trick to placing and adjusting the sub so that it perfectly blends into the mains, so that you can't tell where the sub is placed? It seems that no matter where I place it, I can tell its there. Does it matter where in what direction the sub is facing? Should it be pointed directly at the listening area?

confused,
Take a look at this Sound and Vision online article on speaker setup.
It will help to clarify how to setup all your channels properly so they are calibrated and how to place a subwoofer. It should answer all your questions.

As for your speaker wire runs, various people use different methods for determining the gauge that is required for certain distances. Just offhand, for runs of around 30 feet, 12-14 gauge should suffice. I have two runs of 40+ feet and i'm using a 12ga wire, but i think if you figure out the annoying math on resistances, etc., 14 ga is also possible. I just choose to err on the side of caution and go with the heavier gauge (looking to the future a bit in case i change my room configuration and distances get any longer).

Chess,

I continue to be amazed by your vast array of links to the appropriate web sites and forum posts. How do you find the time?

chess is much like zathras at Ars. He's not a real person. He's actually a very complicated AI that runs on the same server as the forum and has the entire forum chronicled in his memory subsystem.

Or perhaps he's insane.

...an insane addict?

CF, back on your 4. I'd assumed that you had balanced the speaker outputs by following the procedure in the 5200's manual and was just asking about the overall level. Certainly, do the balancing procedure regardless of where the individual level controls wind up.

On the sub location your 5200 sub out(which I assume that you're using) crosses to the sub at 100hz, which is a bit high and sometimes causes localization problems. Putting the sub in a corner and directly behind one of the M1s, if possible, would help with the illusion that the bass was coming from rhe M1. Another possible move is to violate the usual rule of leaving the sub crossover turned all the way up. Try setting it in the middle or a little higher to see if the additional rolloff of the sub that this causes will make it less localized. This might be the lesser of evils.

Yet another possibility is that you simply have the level control on the sub set too high and that's why it's calling attention to itself. Experiment.