Which subwoofer phase should I set?

[JustAnAudioLover]

Hi there!

Due to space constraints, I had to position speakers in a less-than-ideal fashion:

(Not exactly to scale)

As you can see, the subwoofer is right next to the couch and, important information, it is facing the L/R speakers.

Basically the L/R speakers are firing sound to the MLP, and the subwoofer is firing sound towards the right speaker.

In this scenario, what phase should I set? 0° or 180°? I tried both settings and it seems pretty similar to me, but I'm not very sensitive to bass, so I'm not sure what I should do...

Thanks in advance for your help!

 

[staticV3]

This should be set on a case-by-case basis, so measure both using software like Room EQ Wizard or HouseCurve for iOS and choose the setting with better phase- and frequency response.

 

[JustAnAudioLover]

This should be set on a case-by-case basis, so measure both using software like Room EQ Wizard or HouseCurve for iOS and choose the setting with better phase- and frequency response.

I unfortunately don't have a calibration mic and use an Android phone :/

 

[DVDdoug]

I would spend hours sweating over trying to figure out the correct cable to purchase.

Maybe don't worry about it.

It's only important at the crossover frequency where the sub and main speakers are both operating together. (That's assuming you have a proper crossover.)

80Hz (a common subwoofer crossover frequency) has a wavelength of 14 feet, so if the main speakers are 7-feet further from your ears than the sub, you are at one-half wavelength and 180 degrees out-of-phase (which means the soundwaves will cancel-out at that frequency and that spot). In that case you can use the 180-degree setting to correct it. With a 14-foot difference, you'll be back in-phase, etc. Probably neither setting is "perfect".

...Sometimes you "main stereo amplifier" will flip the polarity/phase.

And... If there is a standing wave peak at the crossover frequency (depending on room dimensions/acoustics) it might be better to have cancelation.

 

[JustAnAudioLover]

I launched a subwoofer test video on youtube and found out that no matter what I do, there seems to be a null in the 60 ~ 70 Hz at 180°, and it gets even worse with phase at 0°.

Seems like even correctly setting up a subwoofer is pretty complicated... I would have thought it would be the most simple thing in the world ^^"

 

[Megaken]

But like if you sit down and listen to 'thanks to you' at phase 0 and then listen again at phase 180 - do you hear a difference?

 

[JustAnAudioLover]

But like if you sit down and listen to 'thanks to you' at phase 0 and then listen again at phase 180 - do you hear a difference?

The song from Boz Scaggs? Just tried, I'm not sure there is an audible difference - but note that I have amazingly bad echoic memory so it's hard for me to A/B compare things even a few seconds apart.

 

[Megaken]

Same here. The reason I suggested that song is because the bass parts there are memorable beyond hearing - you can feel it emotionally, especially if fronts are time-synced well with the sub. I use it to confirm dsp/room correction setups. It should be played from an uncompressed source like qobuz rather than YouTube or spotify. But if you don't feel much difference - I'd keep the phase at 0.

You can also search youtube for tricks -

 

[Keith_W]

I unfortunately don't have a calibration mic and use an Android phone :/

I think there should be a general warning on ASR that everybody who buys a sub should also budget for a microphone and preferably some kind of DSP. It is impossible to tune a sub properly without a mic.