How to guide: Setting the delay between the left and right speakers.

[Axel]

Ok guys, so ive finally gotten this to a point and played around with enough programs that i think this will now be straight forward and easy enough for everyone.

This method gets your speakers PERFECT if you give it even 20 minutes.

You are going to need 2 programs - Audacity (free program) and adobe audition (30 day trial is available) and 1 audio file

You can download the audio file that you will need for this guide here https://www.dropbox.com/s/ddvs7yrhqef56c...t.wav?dl=0

So what i did was put a 9000us delay on the right channel (putting a big delay on the main channel means we can guarantee we are looking at the right pulses and know what channel they are in)

warning - PLEASE TAKE NOTE - warning - when you open the speaker settings in the configurator, there is a crossover/delay section for if the pre-out is enabled and if the pre-out is disabled. For all of us with pre-outs feedings subs - every time that you load this section up it will always open in the pre-out DISABLED section. you will change your settings, put the sd card back in your devialet and go why the heck didnt the settings change.. i did it so many times its not funny.

ok so now the master amp will be the delayed note by a serious amount so there can be no confusion.

First step - open audacity.

go to file - open then go to the dirac pulse file that you downloaded from this thread.



once you do that it will load the audio file. here you can see the dirac pulses i was talking about



So the top box is the left channel and the bottom is the right.

From here - open audition.

Once you are in, towards the bottom right there is transport controls. click on the record button and it will bring up some options. record at 192khz. it will start recording so just press stop.

Once you are ready, press the record button then quickly alt-tab to audacity and press the play button. once the clicks have both played alt-tab back to audition and press the stop button. You are going to look at the recorded section and think to yourself - why is it still blank - dont worry it recorded.

Where the transport controls are there are some magnifying glass icons. press the plus on the left until you can see the two pulses, then with your mouse click on the screen in between them so that you see the red marker line. after that press the magnefying glass on the right a few times. play around with your zooms and eventually you will see this:



now put your cursor dead centre on the right pulse and keep magnefying until you get a screen like this: please note - my apologies on being a really bad mobile phone photographer and its too late for me to retake these photos.



You can quite clearly see the 2 different pulses. The first pulse you see here will be the devialet slave unit. the second pulse is the master unit (we have a big delay on the master remember)

click your mouse on the first pulse like here and note the time. mine was "xx.373" then click your mouse on the next pulse like this:



and note the time. mine was "xx.380". we put a 9 micro second delay onto the master channel but here its telling me the actual delay is only 7ms. So from here you need to go to the configurator and take off that time from the delay. So i changed my delay from 9000us to 2000us and put the SD card back into the dev.

Now you need to do another recording of the pulse.

Now for your reference im going to show you this next photo. its the extremely zoomed in version of the FIRST pulse using the magnefying glass on the RIGHT hand side.



There is a few things here you need to pay attention to.The size and shape of the waveform. Also note after the initial peak how much further down the pulse goes past where it started in the negative region. its about 2 rectangles exactly.

From here, unzoom on the first pulse and zoom right in on the second pulse and it will look like this:



So the first part of the pulse is identical to the first even in the negative section it has the same extra length after the peak.

The second pulse combines a negative and a positive pulse. If the negative pulse happened at the same time as the positive - they cancel each other out completely.

if the negative pulse happened at the same time as the negative "dip" in the first pulse it would strengthen the pulse and extend much further. it did neither of those things so i know that the second negative dip is actually the negative pulse. it is smaller than the first positive pulse because it is being cancelled out by part of the positive pulse which you can see in the first photo.

so you need to find the time difference between the positive pulse and the negative pulse. for me you can see there is about a 0.1 micro second difference. so i pull the main devialet card out, jump into the configurator and change the delay from 2000us to 1900us.

pop the card back in and one more time record the pulse from audacity. Here you can see how good your delay is. Here is the final photo from my install:



Notice how the second pulse is about 1/3 the size of the first - that is because the negative and positive pulses are cancelling each other out! this is how you know your speakers are properly timed.

Now if you really want you can keep making adjustments to your delay and get that second pulse even smaller - but people arrived home just as i got to this stage and to be honest i dont think i will go much further but that is up to each and every one of you.

If any one has any questions feel free to ask and ill try help as much as i can.

Looks like you've gone to a lot of trouble to set this up! Great job.
One question: sorry if I am being a bit thick here, but if you are sitting equidistant from your speakers, would you still need to do this? If so, what would the benefits be?

Cheers,

Al