Axiom Home Page Forums General Discussion Technical Questions Driving a load with less than 4ohm

Guys:

This questions is actually for the Outlaw Hideout, but the two times I posted questions there, no answer from them.

I have both VP100 and VP150. The VP100 was my initial experiment of a direct radiating rear channel for my original 6.1 setup 1yr ago, for space reasons, and I did not study as much in the Axiom board like I do now. Then I got 2x M22's as rear channels. Now the system is too big for the room, but I will have the room someday...

Anyway, I did parallel the VP150 and the VP100 just for the sake of it, as the VP100 is just laying there doing not to much. The combined impedance is 3.43ohm. I am driving it with an Outlaw 770, that goes up to 4ohm as the spec sheet, but I dont know if you guys have any experience driving this lower-than-spec impedance. The center channel I know is not driven too hard anyway, but I use a lot of
surround modes that uses a lot of the center channel.

Actually, I am not worried about this,the 770 have shown to be a champ in terms of driving this speakers to ridiculous loud levels without a hitch. But I will like too see if any other person is doing something like that with their amps.

I have seen the posts on loading 4-ohm into 8-ohm receivers, and the current capacity, ovecurrent and thermal shutdown, clippling and distortion, etc.. so my questions is not related to those answers, is just a survey to see if this is a common practice, or if I just went crazy with this setup.

For the record, I like the double center with the movies, but with the music, I rather disconnect the VP100 (if I am listening in surround using center). It might be something to do with dispersion, the tweeter configuration, distance to the fronts, etc... but it feels overwhelming, shadowing the stereo from the fronts; I am talking with the proper calibration, but if I reduce the level of the center channel in the pre-amp, like -3/-4 dB than the calibrated value, then the double-VP does sound really good across the whole room. That is what I actually do, as I have memory presets for the different content I am playing at the moment.

Wow, that was a little long for a simple question.

Thanks

Alberto, using two center speakers in parallel isn't common, but isn't extremely unusual either(when I first got my M22s I briefly experimented with using them in various center channel configurations). Of course when it's done usually the two speakers would be identical, so in that respect your setup is quite unusual, but if you like it, fine. How are they arranged; horizontally, vertically, etc.?

You calculated the parallel impedance correctly, using the nominal 8 and 6 ohms( 1/X = 1/8 + 1/6 = 7/24, X = 3.43), but of course at some frequencies the actual impedances drop below the nominal figures. Apparently the 770 still approves.

I imagine a lot of people are doing this without realizing it. Every few months we get a post from someone who is running three or four sets of speakers wired in parallel and wondering why their amp is running hot. I think the record was about 1.2 ohms...

The VP's are in a horizontal position, side to side. They were originally in the top of a old CRT RPTV, but now, with the new DLP set, there is no space to put them on top, so I am just positioned them under the tv, in a shelf, laying on the wedge side so they points angled upwards.

Now that the speakers are under the tv, the problem I had of the overwhelming center its kind of gone. I guess that this big center is better positioned under the tv in my particular room setup.

thanks