does anyone use subwoofers in their setup?

[baconbrain]

So I set the delay for the subwoofer preout as mentioned above and from an sw integration perspective, it sounds like a step in the right direction. I have now been experimenting with the phase settings (my sw has four, 0,90,180,270) and percieve 90 to be the one which gives me the best results, but what exactly is phase doing? I read the sounddoctor article, but still don't get it ...

Can someone enlighten me?

[thumb5]

So I set the delay for the subwoofer preout as mentioned above and from an sw integration perspective, it sounds like a step in the right direction. I have now been experimenting with the phase settings (my sw has four, 0,90,180,270) and percieve 90 to be the one which gives me the best results, but what exactly is phase doing? I read the sounddoctor article, but still don't get it ...

Can someone enlighten me?

Yes, confusing...from what I've read, it's typically a delay adjustment expressed in terms of phase at 80 Hz (by convention).  You might want to check that in the user manual for your sub-woofer, if you can.  If that is the case for your sub, by my maths that means each 90 degrees of phase adjustment corresponds to a delay of about 3.1 milliseconds (360 degrees = 1/80 seconds = 12.5 milliseconds).

[completeluxury]

Correct. by phase - it means if you looks at an 80hz sound wave it will be like half of an AC sinewave, it raises up to a peak, then drops back down to 0.

So to move it 90 degrees means basically a 1/4 of the sound wave, 180 is 1/2 and so on. its basically a delay stated by how much of the 80hz sound wave it delays by.

[Antoine]

So I set the delay for the subwoofer preout as mentioned above and from an sw integration perspective, it sounds like a step in the right direction. I have now been experimenting with the phase settings (my sw has four, 0,90,180,270) and percieve 90 to be the one which gives me the best results, but what exactly is phase doing? I read the sounddoctor article, but still don't get it ...

Can someone enlighten me?

You need to apply the delay to the fronts, not the sub (assuming your sub is near to your fronts/mains). It's the sub and any DSP in and/or in front of it that "lags".

A stepless phase control really would be best. During setup in my system I've noticed there's a real small "window" where things are optimal, just the tiniest change of the dial would again result in an out of phase setting again. (it's a bit like tuning to a radio station)

If there's no stepless phase control available I'd rely on the frequency amplitude measurements of a tool like REW (sounddoctor also mentions this). There you would look for the highest amplitude at the crossover frequency with the different subwoofer phase options to determine the phase setting nearest to optimal.

Devialet implementing a real time setting of the delay option so that we can change while listening, or even better doing real time measuring would indeed be very useful.

[baconbrain]

You need to apply the delay to the fronts, not the sub (assuming your sub is near to your fronts/mains). It's the sub and any DSP in and/or in front of it that "lags".

A stepless phase control really would be best. During setup in my system I've noticed there's a real small "window" where things are optimal, just the tiniest change of the dial would again result in an out of phase setting again. (it's a bit like tuning to a radio station)

If there's no stepless phase control available I'd rely on the frequency amplitude measurements of a tool like REW (sounddoctor also mentions this). There you would look for the highest amplitude at the crossover frequency with the different subwoofer phase options to determine the phase setting nearest to optimal.

Devialet implementing a real time setting of the delay option so that we can change while listening, or even better doing real time measuring would indeed be very useful.

Ok, so in essence phase is another possibility to adjust timing. What throws me off is that one would think if the delay settings were correct to begin with then you could leave phase at 0?
My subwoofer is closer to my listening position than the mains and for that reason I am applying the delay to the preout for the sw.

[Antoine]

The (mechanical and electrical) reasons behind delay are described in the Sounddoctor links.

10ms equals to around 3,43 meters distance. You'd also have to factor in the group delay of the sub and any DSP in front of it and subtract that. Once the number goes negative you'll have to delay the mains.

[Stigmater]

You need to apply the delay to the fronts, not the sub (assuming your sub is near to your fronts/mains). It's the sub and any DSP in and/or in front of it that "lags".

A stepless phase control really would be best. During setup in my system I've noticed there's a real small "window" where things are optimal, just the tiniest change of the dial would again result in an out of phase setting again. (it's a bit like tuning to a radio station)

Stepless phase controll indeed best , i found that on 80Hz sample i found very smal window around 40" on SW
and exactly as Antoine mentioned , tiniest change would result in an out of phase, not in a million years i would find that spot with out trick from sounddoctor.

 
I personally didn't liked the sound when Speakers and SW set on 80Hz as recommended by sounddoctor ( Speakers Hi pass 80 Hz, SW low Pass 80Hz)
So if after setting the correct phase by playing 80Hz sample i changing the setting in Devialet back to Full range speakers and 35Hz low pass on SW,
does phase that i set earlier is correct now for new settings as well (35Hz low pass on SW)?

if so , what delay i need to apply if my SW is in the left corner next to my left speaker along the wall 3.5m away from my listening position ?
The delay i should apply on speakers or on SW ? (According to my understanding its on speakers)

[Pascal]

Hello,

Can anyone shed some light on how to calculate the delay for the subwoofer. I asked the manufacturer for the amount of delay on their subwoofer (Monitor audio SW12) and got the following response:

“The DSP core has no delay added to it and the internal processing delay is 1 Sample. The ADC and DAC also add some small amount of delay but again this is around 1~3 samples. The total delay input to output will be much better than a very worst case of 10 samples and the DSP core runs at a sample rate of 48kHz so this is equivalent to 0.208 milliseconds which is phase terms at 80Hz is 5.7 degrees.

The delay in distance is 7.1cm which is usually a lot less than the error in path length between the speakers and the subwoofer. Also at these frequencies the difference either of these will make will be very negligible as the frequency response is dominated by room modes which will be orders of magnitude greater in their effect on the frequency response.”

The subwoofer is (counting from the listening position) about 60 cm (1.9865 feet) further away then the main speakers. I read in the posts that I should delay 1 milisec per 1.13 feet (34.44cm).
Does this mean that I should delay the main speakers with: 0.208 milisec + (1/34.44*60) = 1.95 milisec --> 1950 microseconds?

Thanks for the help.

Pascal

[thumb5]

Hello Pascal - your calculation looks right to me (for what that's worth!). Looks like you got a helpful reply from Monitor Audio.

[thumb5]

Having said that, there may also need to be a delay adjustment to cater for the phase difference between the main speakers and the sub-woofer at the cross-over frequency. There's an interesting article about this here: http://www.rythmikaudio.com/phase1.html.

So probably you need to measure the response and play around a bit with the delay to get the best result. Good luck - I would be interested to hear how you get on as I need to do something similar when time allows.