Smaart - sub woofer alignment with Keith Morris

Short and sweet way to get array and subs aligned

[rashofbeatings]

Thanks for your videos.. i was a student/graduated in 2006.. been working in live sound, post production & system installations ever since. Thanks to everyone at CRAS for your work! God bless

[leadaudioengineerlasvegas]

Keith, I love you. you are awesome.Thanks for giving back and helping our next generation. I'm just and old FOH A1 in Vegas and have been sending my techs to your videos to help them out. Keep it up, you're making a difference. Peace to you.

[NBDY_SPCL]

The method you describe is pretty solid with delay. The phase inversion doesn't have to be exclusive of delay, either. I tend to not invert, because (in outdoor scenarios), I will often try to employ Endfire-type techniques for sonic containment.
This requires at least 4 points of sound, though a 4.3 system (tops in each corner, summed sub array in front, rear corners are full range) has worked best so far. Essentially, you measure from the center of the space, first aligning the front tops with the front sub array, then aligning each rear top with its respective subs. Once you have that done, you move to the rear line and you delay the rear stacks until you are 90° out of phase from the front stack. Step back maybe a foot further away from the front stack. If you have adjusted things correctly, you will get a summing of the signals inside your sound space and almost total cancellation outside of if. You may have to fiddle a bit with your times, and the more bands of delay you have, the more profoundly you can create this effect. When I say fiddle, I mean tenths of a millisecond for mids and highs, so lightweight processing isn't going to do the job.
It does work, I've done it, however, it's not easy, it's very time consuming, and I would only suggest even thinking about trying this if you own the system, or have a very supportive owner and team who are willing to give you the time to try and fail until you get the hang of this. If you can get it right, you absolutely blow minds because if you are outside of the field, you will question whether the system is even on, and then as soon as you cross the threshold, the sound hits you like a wall.

[seanmakessound]

Thanks for the video! Definitely a good review for the System Engineering practical I'll be taking tomorrow!

[kappabravomusic]

7:49 absolutely, most of the time there is few various solutions to the problem solving path. Cool video. Thanks

[airwickyeager]

Keith, you're a badass. Thanks for teaching me the skills to be successful. I'm still trying to nail good mixes fast but it'll come with time, I'm sure

[joes]

Keith is a great teacher!!! Thank you for sharing!

[timogletree]

Nice job Kent. Some food for thought... not that I have a conclusive answer or the point is mostly academic... but in this scenario we're looking through the perspective of a continuous signal. What about a transient? Polarity or delay the better choice? Also, important for everyone to understand the alignment is only as good as the design allows the alignment to be consistent over as much audience area as possible. A whole other topic....

[DJAlstein]

I love the way you explained it, please do a Video about PA basics

[SiaDavarnia]

Thank you Keith.. Delaying or Polarity inverse would essentially be the same in this case, 8ms delay would be half cycle of 62.5hz which you spotted the alignment is needed. correct me if I am wrong, thanks in advance...

[JerryD]

Have you compared this method to using the "delay locator" method? If I wanted to align the tops to the subs or vice versa - I would want my crosshairs (cursor) to be exactly on the crossover point on the magnitude trace AND I would want the phase traces to align at that position as well. That is why you have the straight line going into to the upper screen with the crosshairs up there as well. They (Rational) made it easy for us to lock it in this way.
It seems you are choosing a different point to align the boxes that is not at the down-point on the crossover where they cross. Can you explain further?
In my mind when it comes to delay vs. polarity - I usually go with whichever option uses less delay.

[HansonProductions]

Problem with polarity inversion vs. time delay in this case: what does polarity inversion do to frequencies above and below the crossover? It may be perfectly aligned at the exact crossover frequency, but is it combing out energy anywhere else outside of the crossover frequency?

I think Merlijn van Veen has probably the best solution for a situation like this. Do separate measurements with both time delay and polarity inversion and not only check the phase at the crossover, but check about 1/3 octave above and below the crossover as well. (If your x-over is 100hz, 1/3 octave below and above would be roughly 80hz and 125hz, respectively). If polarity inversion causes weird buildup or cancellation of frequencies, then it's not the ideal solution (likewise with time delay).

[duanelr]

Good video. But more people might have a deeper understanding if he defined his terms. Plot the trace, phase wrap, delay locate. These are all Smaart terms that are simple in concept but students may not know.

[CKDrumsInc]

Great video, just a bit confused, is the oscillator still on 5.20seconds, just low that we couldn't hear it? (otherwise surely it's just matching the output time which I know you aren't doing) or is thee a way to monitor the differences without noise?

[domwujek]

WOW So it really has been a while since ive watched audio related video and didnt understand a thing!

[dharshanaperera]

Great video. Thanks for the video. I have Smaart v6 how to alignment sub on smaart v6???

[ivandaniels]

Keith, can’t knock you for making a decent video. However, you failed to show your students the full picture when it comes to possible differences between your polarity inversion vs. time alignment. For one, it was by chance (or perhaps by design for the sake of your video) that polarity inverting your subs aligned the phase traces. That’s going to be a shot in the dark for many deployments. A student should see what happens in the crossover region after you’ve applied the two different actions outlined in your video. With the polarity inverted on the subs, what does the measurement look like with the main array added back in? Do you have proper summation above and below the crossover frequency you were focused on? With both systems energized, do you have significant cancellation in the crossover region if you flip polarity back on the subs? How does this compare to the delay method? If the subs remain in relative phase and you time align them to the tops, do you have more or less summation in the crossover region? If you flip polarity on one of the systems in this case, do you have more or less cancellation. You may be misleading your students by not showing them this additional context for measuring and tuning crossover points. You might be “in phase” at that one crossover frequency by overall out of time. You may be giving away “free” energy of the systems aren’t properly time aligned through the crossover region. You should see distinct summation through the crossover region with both systems time aligned and and in proper polarity. If this summation produces undesirable frequency response, apply corrective EQ. This way your system design is benefiting from the “free” summation energy. You may have been there with what you demonstrated with the sub polarity flip, but I feel you need to demonstrate how to validate it with additional measurement.

[BjorgenEatinger]

What crossover are you using? I didn't hear that mentioned anywhere.

[brianchristopher]

My question is "aligned from WHERE??!" Measuring from one spot/seat in the room will make for a varried results from other locations of measurement, depending on relation from seating locations vs subwoofS locations, and sub to sub respectively and in assocation??? Seams one sub will be close and one far from any given seating, so how do you balance and for Phase on that?! Seams challenging if impossible to balance for all seating locations in this particular instance. Besides my marbles, what am I missing here???

[godwashereable]

Keith, very good video! Thank you very much! My question is if the subs are really far from the main.. let say the the main is 10ft behind the subs, then do we have to find the delay time between sub and main first and then phase match them?? And how do we find that delay?