sub out-of-phase sounds better?

[Bevan]

hi, i'm hoping for some help again.

trying to set up my new sub, using denon 2200 with speakers set to small(80hz)

when the sub is in-phase with the speakers i have a large peak in my requency response through the crossover region. when flipping the phase switch the response is a lot flatter.

i'm wondering if there is any inherent problem, musically speaking, if i run the sub out-of-phase?

thanks for any input


b.

 

[j_garcia]

Entirely depends on your particular room and your speaker positioning, seating position etc.... Your phase setting should be adjusted to whichever your sub sounds strongest/cleanest on.

 

[edwelly]

I changed my yesterday and while it was not a HUGE difference I could tell some change. I left it out of phase as it seemed smoother, less boomy...

 

[MDS]

The whole purpose of having a variable phase setting on the sub is to help integrate its sound with the rest of the speakers. If yours sounds better run 180 degrees out of phase, then that is the right setting for your particular room.

 

[Bevan]

thanks for the speedy replies.

seems i need to get out some music rather than be messing around with test tones.

j_garcia, by in-"phase" i mean what gives me the most output around 80hz, not 0 on the phase switch. is the best real phase for the sub still dependent on the speakers, sub, listner possition or do you just mean the relative 0/180 phase setting? can strongest and cleanest be contradictory? because i always read that one should go with the phase setting that gives the strongest output through the crossover frequency i.e in-phase, but if one already has large room nodes in these frequencies it makes sence to go with the polarity that minimises output here?

i would think that whatever gives the flatter curve is best, but my avia dvd in the sub phase sections mentions not only volume differences as a way of determining what is in-phase(they recommend to go with what sounds loudest through 80hz), but also to listen for what gives a subjectivly smoother sound. this is why i'm thinking that the flatness of my frequency response might not be the only issue.

i'll play some music and decide what i think sounds better, but i'll have to wait till tomorrow for that so's not to wake the neibours(appartment ). also wish this damn sub had a remote... might have to enlist the help of my significant other for this...

cheers

b.

 

[j_garcia]

If you only have 0 and 180, then go with the one that sounds best, as MDS said. Some subs have a continuously variable phase adjustment.

Yes, strongest and cleanest (flattest) can certainly be contradictory - depends on your room. Flatter may actually sound softer (due to fewer/no peaks), but when calibrated, should actually be hitting roughly the same levels. It really is a personal preference, and if you like the way it sounds with it set to 180, then that's what you should use.

Are you using Avia to do a sweep and that is how you are determining you have flatter response with it at 180?

 

[Bevan]

ya, i'm using the avia 200-20hz sweep and the rs spl meter.

had a quick listen to music now and the sub is sounding pretty damn amazing. well, the sub doesnt sound, just the music!

i have it at the "0' setting, but i'm calling that "out-of-phase" here as it delivers appreciably lower spl's from 75-85hz. i have it positioned in the front right corner about 5 feet behind the speaker plane, 38cm from the font wall and 10cm from the side wall. it's facing backwards and towards the side wall at a 45 degree angle. is this wierd? it's the only possition my too-short power cable will allow.

will fiddle more later when my girlfriend gets home. with the phase switch.

b

p.s the sub is a dynaudio 250 (8inch, sealed). first product i ever bought without reading one single review on it(there are none on the net believe it or not). did home audition first though. very happy so far.

 

[j_garcia]

Generally speaking, "0" works in most rooms. I wouldn't say it's weird, because my sub's position is dictated by the length of my signal cable

 

[Bevan]

wow, ran the sweep one more time. not only is my two main peaks at 80 and 90hz down, but the only real dip i had in my curve, a 15db hole at 102hz, is completely gone.

i wonder why avia and everyone else i read advises to go with whatever phase setting gives highest output over the xover range? maybe i just have lucky room dimentions? (5.45mx4.4m)

 

[BGLeduc]

I have been taking a lot of measurements in my 2CH (sub/sat) room using a Behringer measurement mic and RoomEQ software. Regarding the question of getting the subwoofer phase right, I have attached two plots of the unequalized room response; both identical save for the fact that the sub phase switch is inverted from one to the other. FTR, I am using an ICBM as the crossover, set to 120 hertz.

Here's the part that surprised me. The response at 120 hertz is better with the phase at 180 degrees; at 0 degrees, its a bit lower. But, look at the area around 120 hertz. Its clear that the overall response in the crossover region is better at 0 degrees, even if the reponse at the exact crossover frequency is slightly better at 180.

I suppose that point is you really need to look at the whole region, rather than just the crossover frequency.

Note that is you put your mouse over the thumb nails, it should tell you which file is which.

Brian