How to practice Merlijn van Veen's Relative/Absolute Subwoofer Alignment Method at home

[@johnschalk1271]

I have two questions about this process. First, at the end of the video you show how to determine the total area of good phase alignment with the systems at the same relative level. But, in the real world for most pop/rock musical styles, we know that we're going to have a bump in the low frequency range, so wouldn't it be better to practice this method with the systems set to your preferred target trace? Secondly, the main issue I have with trying to apply this process in the real world is with viewing the phase trace for the main system with its HPF engaged. I understand why that is the case, the the slope of the HPF makes say 60Hz too low for good coherence, but how to account for this? Must we disengage our HPFs to use this process? BTW - I have never gotten all the way through Merlijn's process even in my driveway, so maybe I'll take a shot at it using MAPP XT/3D.

[@nathanlively]

Hi John! > wouldn't it be better to practice this method with the systems set to your preferred target trace? Yes! > how to account for this? Can you share an image of what you're seeing? By the time we get down to 60Hz, it's rare that the main and sub would still be interacting. We really only need to focus our efforts in the region where magnitudes are still within 10dB. Within 20 or 30 if you want to be extra critical or have the time. > Must we disengage our HPFs to use this process? No, this would defeat the process. > I have never gotten all the way through Merlijn's process even in my driveway Hmmm, sounds like there may be something strange going on. Some ideas: Record your process and post it so we can offer feedback. Write it out step by step and comment here. Practice with some traces from Tracebook first.

[@johnschalk1271]

@@nathanlively I am attending a Meyer Sound System Optimization class this week, so I am hoping that I can get my questions about sub alignment answered . If not, I will post more details here.

[@user-if3to7pz6q]

Thank you for the good video. I have a question. 1) MerlijnvanVeen's article adds the phase of woofer and main, is there a reason for calculating by subtracting the phase of woofer and main in the video? (4:12) 2) MerlijnvanVeen's article delays main speaker and reverses phase Is there a reason to give phase inversion and delay to the woofer in the video? (7:50) Is it because the delay value is negative?

[@danielugochukwu6011]

Great work Nathan. Thanks so much. Pls whats the name of the software?

[@nathanlively]

MAPP XT?

[@cephaswesley7684]

Why dint you use HPF LPF on the mina and sub? I believe you could have avoided the polarity reversal bit and in the filed if you do end up using filters wont these presents become obsolete? Merlin also had a post on measuring with the filters. Let me know what i am missing. Thanks for making amazing videos!!!

[@nathanlively]

Hi Cephas. Thanks for checking out the video. >Why dint you use HPF LPF on the mina and sub? Just to keep things simple, especially when practicing. >if you do end up using filters wont these presents become obsolete? Yes, if applied asymmetrically.

[@malcolmtitan8602]

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[@jasperjoseph872]

@Malcolm Titan Instablaster :)

[@malcolmtitan8602]

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[@malcolmtitan8602]

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[@ing.brunoramper2917]

Where Does the 0.9 comes from ?

[@nathanlively]

The formula for sound speed in air is c = (331.4 + 0.607*temperature (°C)) in m/sec. The imperial version is c = (1052 + 1.1*temperature (°F) in ft/sec. For example at 22°C: c = (331.4 + 0.607*22) meters/second c = 344.75 meters/second Wrapping our brains around the sound speed formula is difficult because the parameters are out of scale to our practical applications: 334.75 meters is too big to visualize and increments of one second are laughably imprecise. That’s a rate of three football fields/second. Does it help to rescale it down to 0.344.75 meters/millisecond? It’s easier to invert the rate to ms/meter instead. This reduces to 2.94 ms/meter @22°C, and can be rounded to 3 ms/ meter. For those using the English system (feet) there are three options: (a) learn the metric system, (b) ms/foot, which rounds to 0.9 ms/foot and (c) feet/ms, which rounds to 1.1 ft/ms. McCarthy, Bob. Sound Systems: Design and Optimization: Modern Techniques and Tools for Sound System Design and Alignment (p. 79). Taylor and Francis. Kindle Edition.

[@hoobsgroove]

how do you add the delay What software are you using to achieve that rew, mini DSP?

[@nathanlively]

Hi Hoobs, I'm using MAPPXT from Meyer Sound to practice.