subwoofer phase

[jordan21]

what exactely is this???

it allows me to set this at normal or reverse but im not sure what this means

for the time being i have it on normal

thanks again

 

[j_garcia]

It depends on where you have located the sub. If your mains are in the front and you put your sub in the back of the room for example, you could potentially have phase issues with the sub; this allows you to account for this to some extent, though a simple 180 phase shift may not solve it completley. If your sub is in the same general area as your mains, normal should be fine.

 

[Halon451]

You should try to re-post this in the Subwoofers section of the forum. But either way, I'll try to help.

Most subs come with a phase control knob/switch that either allow you to set it at 'normal' or 0 degrees, or Inverse or 180 degrees. Some allow you to adjust the sub's phase throughout the entire range from 0 to 180 or (I think), 360 on some models.

For most applications, if you have your main speakers set to 'small' and LFE set to sub only with a reasonable crossover setting at your receiver (say, 80 Hz), the phase will be fine set at 'Normal' or '0'.

All this does is allow you to control the driver's response relative to your other speakers in your setup (someone correct me if I'm wrong here), meaning that ultimately it's allowing those longer low frequency waves to reach your ears at the same time as the sound waves from the other speakers, so that (at the listening position) the sound is 'in-phase' and therefore does not contain any additive or negative (cancelling) effects to the overall sound.

There are some good audio test DVD's out there that can help you figure out which setting works best for your setup/environment, but like I said, for most situations, you should be fine with it at 'Normal/0'.

 

[Antus]

because high frequency and low frequency have different wavelength, at certain sound may arrive your ear sooner (or later) than the other. as a result, you may want to speed up (or delay) certain frequency so that all frequency reach your ear at the same time.

natually, an external sub will potentially have phase problem. when you think about it, it make sense. a signal will go through longer cable to reach sub (a potential delay) plus the signal has to go through crossover network and amp inside the sub to produce sound (a further delay) as a result, a lower frequency will arrive later than mid/high frequency.

there are some ways to adjest for the "out of phase" problem. the ideal way (for purist) is to relocate the sub so it will be "in phase" with other frequency. (u can move the sub toward or further away from listening position, so the frequency will "line up"). another way is to adjest the "phase" control.

in my opinion, human ears are not that good. unless it is really our of phase, you won't feel it. use a microphone to help you set up the system will be a good way to start.

btw, slightly out of phase sometimes may not necessary a bad thing. some people actually like it. if mid/high reach ur ear faster, the speakers(system) will sound more "forward", "fast", or "in your face" and in vocal recording, u will have the "feeling" that the singer is right in front of u.