I have a pioneer 84 - that has MCACC - it's a way of equilizing a room.

Anyway, I just got my new Focal Electra SW1000 - and when I run
the MCACC it states that the distance is 26.5' - which is almost
double what it should be. The loaner sub - I think didn't have this problem.
All my other speakers - are pretty much - what it states.
This sub - does have phase control - Is phase used in calculating distance?
If so, should I change the sub output - to make the distance correct?
What does it sound like - when the sub is out of phase with the rest of the
speakers. This is my first sub.

Yes, MCACC uses phase to calculate distance.

I'd probably adjust the sub's phase setting until the calculated distance is as close as possible to the real one, but I'm compulsive about such things. Chances are, you are fine as is and won't hear much difference.

The most common symptom of an out of phase sub is a reduction in bass output, especially around the crossover point. Sometimes the difference is obvious, sometimes you need a meter to detect it.

Ed spoke about this in a post a while ago. I can't remember the technicalities but the recommendation was to leave it alone once the auto calibration does its thing. Just be sure to check that your mains are set to small after calibration.

Ed spoke about this in a post a while ago. I can't remember the technicalities but the recommendation was to leave it alone once the auto calibration does its thing. Just be sure to check that your mains are set to small after calibration.


Right now I'm experimenting with the mains set to large and small. I know it
is usually recommended to set them to small. But shouldn't it matter on the
quality of the speaker and the amp, you are using.

Only if your mains' low FR is as good as your sub. Set to Large, all LF in the main channels goes to the main speakers including frequencies they can't reproduce. Those are just lost, as only LFE goes to the sub. Set to Small, everything below the crossover is directed to the sub. Usually, you are better off letting the sub handle all the lows.

As a side benefit, you reduce distortion in your mains and ease the load on your amp if you use Small.

There are exceptions to most rules, of course, but generally setting the mains to Large also increases the possibility of phase cancellation resulting in degraded sound at least some of the time (depending on the sound track mix).

You'll find "experts" (including most sub manufacturers) pretty uniformly recommend setting the mains to Small. However, MCACC seems hell-bent on setting the mains to Large if they are capable of any response at 40Hz. They have to be set to Small manually.

To clarify my previous post, I'd let the MCACC have the last pass then leave it alone even if I did manually adjust the sub's phase setting. It will do a better job of final fine tuning than I could do. I'd only fiddle with the sub to get it's initial phase setting closer to right because I'd feel better if I did, not because it is likely to make a noticeable improvement.

The MCACC is actually acoustically correct with it's seemingly incorrect distance setting. Leave the setting as it sets it.

yes the distance settings from my elite 81 seem to be fine- even though a bit off as far as the distance it reports.

however i find the volume it sets the sub to to be far too low. after double checking with an SPL meter i find it to be around 6 db too low. anyone else find this? and have you increased the level to compensate or did you leave it "as is"?

Distances measured by automatic measurement systems can be way off because of electronics or other components which cause delays. A bit like lip sync problems between video and audio. After making sure the phase was set to zero I would leave the setting as MCACC measured it.

however i find the volume it sets the sub to to be far too low. after double checking with an SPL meter i find it to be around 6 db too low. anyone else find this? and have you increased the level to compensate or did you leave it "as is"?
I would seriously look into proper placement of your sub. Often these differences in volume are caused by huge peaks and nulls in the frequency response caused by room modes.

I would seriously look into proper placement of your sub. Often these differences in volume are caused by huge peaks and nulls in the frequency response caused by room modes.

I have to agree. With my sub in the front left corner, and calibrating at the sweet spot, it used to raise my sub +1. Not bad at all. Until, on a whim I calibrated the levels 2 feet over on the couch and the sub was suddenly -7db. I was sitting in a huge null that I was able to verify once I got my sms-1 and could see the frequency response on the screen. So while the levels might of been right for that one spot, anyone else in the room was getting a ton of bass. Moving it to a location behind the couch smoothed out the frequency response across the entire seating area. There's no substitute for good placement.

i will try that. i have it calibrated in my sweet spot. my room is a bit of an issue- as well my sub may be too. i have a smaller cramped living room and an x-sub i got the x-sub due to space constraints. and while i do really like it i wonder if i would be better off with something slightly bigger in a more obscure placement.

thanks for the input i had been considering placement an issue. and that is what it probably is. actually i KNOW thats what it is. that and a more efficient sub. i have it next to an opening to a kitchen area- due to space constraints. i will run the real traps test and i will place it elsewhere.

so with the real traps test you want to find the area of placement with the LEAST amount of nulls on the spl correct? in all seating areas. so the response on the spl should be even across the seating area? even better if even throughout the entire room?