does anyone use subwoofers in their setup?

[brit]

ok so basically ive set my room up pretty well at the moment so that i have a pretty constant and linear system in regards to the sound output at all frequencies.

a 40 hz room mode means that at 40 hz, the system is 10 to 15 db louder than the other frequencies (and we all know that a 10db increase is actually double the volume)

ill take some photos over the weekend when im working on my system to demonstrate what i mean and how it looks when measured on software

Many thanks for this explanation - now looked up room modes on t'web - helpful. I am afraid that I have not yet ventured into the realms of room "tuning" (if that's the right word!) and possibly won't as it seems fraught with it's own set of problems - bass traps and all that. Anyway hope you resolve your 40Hz room mode .

David

[Stigmater]

Great news, output delay is finally implemented in to configurator,
its measured in microseconds (µs) which is one millionth of a second.
The question is now, what value to choose?
i think based on what i read here , good point to start on 10ms delay which is 10,000 µs in configurator.

Or maybe the delay I should do on my speakers and not the sub ?

Please share your experience and tips on how to configure the delay for optimal Sub integration.

[completeluxury]

stigmater my question is - how do you know that your sub is out??

for me i wont be using this to delay the subs to the towers. instead - my listening position is slightly off centre from my speakers so there is a slight timing error between the left and right channels which it will be used to address

[muski]

Great news, output delay is finally implemented in to configurator,
its measured in microseconds (µs) which is one millionth of a second.

First, I'm so impressed by the responsiveness of the Devialet team in adding this feature...

Stigmata, you're correct—indeed it is in microseconds. Before this feature was fully implemented, the wonderful Devialet support team kindly made me a hand-crafted config file with a 3 millisecond delay on my mains. So just to confirm things, I loaded this file into the Configurator and saw it as 3000.

I suggest looking at the methodology proposed by Barry at  http://www.soundoctor.com/whitepapers/subs.htm. He recommends setting the mains delay a little high (say 10ms) then using the Phase knob on the sub to slightly delay it to match the mains. (He uses a brilliant trick of playing an 80Hz tone through the sub and a reverse-polarity main and adjusting the phase until the sub & main cancel each other out.)

The problem is that many subs don't have a Phase dial (they just have absolute polarity), plus I just don't like the idea of over-delaying the mains and the sub. As a next step, I'd love to see Devialet add a feature to allow realtime adjustment of the delay with the remote. Then you wouldn't need a phase dial on the sub (or a remote helper to twiddle the knob). You could sit in your listening position and adjust the delay until they matched perfectly. And because the delay setting is in microseconds, there'd be enough granularity to get it spot on. I've never heard of a 2-channel device that can do this.

So amazing what you can do with an audio device when it's got such a powerful processing power inside.

muski

[baconbrain]

A question on the subwoofer experts regarding properly setting up delay to ensure acoustical phase.

If my SW is located 11.4 feet closer to my listening position than the main speakers, then I will need to delay the output to the SW by 10.08 millisecs (11.4 feet divided by 1.13 feet per millisec) to correct the timing between the mains, sw, and listening position. I will also need to subtract the processing time of the sw dsp (1.5 millisecs per manufacturer) from this amount to arrive at a revised total delay of the subwoofer preout by 8.58 millisecs.

Is my thinking correct?

[Jean-Marie]

A question on the subwoofer experts regarding properly setting up delay to ensure acoustical phase.

If my SW is located 11.4 feet closer to my listening position than the main speakers, then I will need to delay the output to the SW by 10.08 millisecs (11.4 feet divided by 1.13 feet per millisec) to correct the timing between the mains, sw, and listening position.  I will also need to subtract the processing time of the sw dsp (1.5 millisecs per manufacturer) from this amount to arrive at a revised total delay of the subwoofer preout by 8.58 millisecs.

Is my thinking correct?

Yes to my understanding.

[thumb5]

A question on the subwoofer experts regarding properly setting up delay to ensure acoustical phase.

If my SW is located 11.4 feet closer to my listening position than the main speakers, then I will need to delay the output to the SW by 10.08 millisecs (11.4 feet divided by 1.13 feet per millisec) to correct the timing between the mains, sw, and listening position.  I will also need to subtract the processing time of the sw dsp (1.5 millisecs per manufacturer) from this amount to arrive at a revised total delay of the subwoofer preout by 8.58 millisecs.

Is my thinking correct?

That's my understanding too.  Lucky for you that the manufacturer can tell you the delay through your sub-woofer.

I don't think I have that information so am trying to work out how it can be measured - if anyone can share any hints and tips that would be most helpful.  (I have FuzzMeasure and REW so I expect it must be possible using those tools, but if I can avoid working out a method from scratch for myself that would give me more confidence that I'll get the right answer!)

[completeluxury]

thumb5 with REW it will be possible, using the time delay graph.

im waiting on a proper how to guide to know how to read them 100% properly ill post it here when i get it

[Antoine]

I'm currently experimenting with the delay feature. Started with the sounddoctor advice and set up 10ms (=10.000 us), disconnected one loudspeaker, wired the other closest to the sub put of phase, played a 80Hz test track and then dialed up the phase on my sub until my dB meter showed the highest amount of cancellation.

It sounds very good but not really sure yet if it's really much better than before. Have to listen more, perhaps I'm hearing a bit more focus/definition/tightness of particularly real bass instruments.

Found out how you can measure the delay using REW (Google) but the method/setting in REW ('Use loopback as timing reference') requires a loopback from soundcard output to input to measure the latency incduced in the PC+soundcard. I can't make that connection so have to look for alternatives. If you don't make that connection REW uses t=0 at impulse peak level making comparisons in delay useless.

If the 10ms is really best in my situation is something that I'd prefer to see back in measurements although I do trust Sounddoctors advice on this value since he is JL Audio's senior support/installer guy and I own a JL Audio sub.

[thumb5]

Thanks Antoine. Since my sub has only reverse/normal polarity adjustment rather than true phase adjustment, I will need to tinker with the delays in the configurator so it could be a slow process using that method... Someone else on the forum pointed out that real-time adjustment of the speaker/pre-out delay(s) via the remote would be nice, and I concur.