Nathan Lively's Blog, page 11

How to take fast impulse response measurements in Smaart© without pissing people off

Use these settings to efficiently investigate room modes with the impulse response module in Smaart.

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Loved this post? Try these:How to use a custom weighting curve in Smaart® and why I don’t recommend it How to Measure and Treat Resonances like Room Modes and Standing Waves with Smaart® 3-Step Configuration Hack to Get up and Running Fast with Smaart® v8 Beta

How to develop a habit of logical troubleshooting, piece-by-piece

Interview with David Scorteccia about troubleshooting signal flow on live sound stages using the Sound Bullet.

This article How to develop a habit of logical troubleshooting, piece-by-piece appeared first on Sound Design Live. Sign up for free updates here.

Loved this post? Try these:Build self-confidence for better productivity with this simple habit of relaxation Real World troubleshooting tips for wireless microphone and In-ear-monitor dropouts and interference Learn from the Sound Engineers for Tori Amos, Prodigy, and The White Stripes Online

Guess How Many Measurements Positions You Need for Proper Output EQ (it’s more than 1!)

Interview with Scott Sugden of L-Acoustics about the sound system tuning automation and the specific number of measurement positions you need to represent an audience for proper output EQ choice.

This article Guess How Many Measurements Positions You Need for Proper Output EQ (it’s more than 1!) appeared first on Sound Design Live. Sign up for free updates here.

Loved this post? Try these:SATlive + Thomas Neumann: Sound system tuning with a single measurement microphone Where do I put the measurement microphone? Smaart is just a tool. You are the analyzer.

My most popular posts of 2019

In 2019 Sound Design Live had 206k unique pageviews from 107k users, 330k video views for 23k hours of watch time, 75k engaged users on Facebook, and 131k plays on SoundCloud. It looks like video is starting to outpace the podcast in terms of maximum outreach. Based on number of unique visits and time spent […]

This article My most popular posts of 2019 appeared first on Sound Design Live. Sign up for free updates here.

Loved this post? Try these:The Five Most Popular Posts of 2013 Top 5 Posts of 2016 Where do I put the measurement microphone?

How far apart can I space my subwoofers?

We all know that pushing your subwoofers together gives you more SPL and less power alley. But what if you want to pull them apart to make the line longer for more narrow coverage?

Imagine a long, narrow room. You’ve got 4 subs. Each of those subs is 3.8 feet wide, giving you a line of 15.2 ft total. That’s going to give you directional control down to 74 Hz. Not bad. But what if you are crossing over at 80 Hz? You need more control.

[image error]Prediction @ 30 Hz

In that case, you could push the subs apart 8 feet, giving you 24 extra feet of line length, for a total of 39.2 feet. That gives you directional control down to 30 Hz without breaking the pattern. Woot!

[image error]Prediction @ 30 Hz with 8 ft spacingHow did I figure that out?

You will always have some amount of subtraction when two frequencies meet at equal level between 120º and 240º of phase offset. What you need to do is make sure that your speakers are within 2/3 wavelength of the highest frequency at which they could combine.

In our case, we are crossing over at 80 Hz, but to be safe I used 90 Hz for the calculation since the Sub and Main won’t be level isolated right at 80 Hz. Then I found the wavelength of 90 Hz, which is 12.5 feet. After that, all I needed was 2/3 of that, for 8.3 feet, which I rounded down to 8 feet.

Those steps again:

F = the critical operational range of your subsmax distance from center to center = (speed of sound / F) * (2/3)

Warning: the pattern will narrow as frequency rises. The tradeoff of pattern control down to 30 Hz is that you may now be too narrow at 80 Hz. The solution? Create a physical or delayed arc.

Further questions?

Click here to download my new eBook, 105 Questions about Sound System Tuning, free until Nov20th. It’s everything you wanted to know about live sound system setup, but were afraid to ask.

This article How far apart can I space my subwoofers? appeared first on Sound Design Live. Sign up for free updates here.

Loved this post? Try these:110 Questions about Sound System Tuning – Pt. 3 Make Space for Bass in Your Ableton Live Mixes One Simple Tool to Find the Right Size Speaker for Any Space

Merlijn’s Subwoofer Alignment Method Will Make You Feel like a Jedi Master

Subscribe on iTunes, SoundCloud, Google Play or Stitcher.Support Sound Design Live on Patreon.

In this episode of Sound Design Live I talk with the senior technical support and education specialist at Meyer Sound, Merlijn van Veen. We discuss subwoofer alignment, subwoofer spacing, and M-noise.

I ask:

In Subwoofer Alignment: The foolproof relative / absolute method you describe a process of comparing two sources in the near-field when they are side-by-side and measurement conditions are favorable, creating an alignment preset, and then deploying that in the far-field with complementary delay to correct for any distance offset caused by moving the speakers apart relative to the listening position. Unfortunately, most of us attend a seminar where we learn how to align two sources and it seems pretty straight forward. Then we get into the field and the whole thing falls apart. Why can it be so challenging to get actionable data in the field and how did you came to develop the relative/absolute method?You published a series of articles on your site called Mind the Gap, in which you share the performance improvements in directional subwoofer arrays caused by adding an air gap between enclosures. You end the articles with this: “the challenge becomes to determine the minimum required gap size for improved rejection without a noticeable increase in lobing.” Do you have an update for us on this subject and any further information on the minimum gap size?Could you give us a run down of the settings you use in your audio analyzer? smoothing, graph limits, averaging, etc.What is M-noise? Do I need to start using it as my test signal in Smaart? From FB Dave Gammon: If he had hair…. would he have a mullet or ponytail… Swapnil Wakodikar: Accessible software for all which provides stimulation of Line array and subwoofer configuration. Ockert Marais: If you could only teach a single lesson about sound system optimisation for your entire life, What would it be? Thorsten Bunz: Did having your own education site and writing articles help you get the job at meyer? How did it change your career?[image error]

If you ask a violin player to describe their violin, you’re going to get an 8-hour lecture because he knows his instrument intimately. He knows everything there is to know about that instrument because that’s how he makes his money. Ask an engineer to describe the phase response of the loudspeakers that he works with regularly and chances are you will hear crickets.

Merlijn van Veen

NotesAll music in this episode by Derrick Bryant.Meyer Sound, MAPP XT, M-NoiseMerlijn’s starting audio analyzer settings: 1/48oct resolution, ±30dB with 10dB divisions, MTW FFT resolution, Complex magnitude average type, 16 FIFO or 1sec averageSC0403-A task groupSound system Design and Optimization: and em Español.QuotesIt’s notoriously hard to absorb long wavelengths.If you have really unfavorable conditions, even using a gratuitous amount of smoothing, typically, will not rid you of those fake wraparounds.If you ask a violin player to describe their violin, you’re going to get an 8-hour lecture because he knows his instrument intimately. He knows everything there is to know about that instrument because that’s how he makes his money. Ask an engineer to describe the phase response of the loudspeakers that he works with regularly and chances are you will hear crickets.I don’t consider ripple a bad thing. It’s arguably the most important metric that there is in interpreting an analyzer because it gives you an understanding of the degree of interaction and direct to reverberant ratio.It’s not about wrong or right. If you know what you are doing, anything goes. If you want your analyzer to become an ally, then the analyzer should render the sound as crappy as it sounds, not paint a picture from a data sheet.It makes no difference which signal we use when it comes to obtaining a transfer function. M-noise does not change my calibration practice.Calibration is the process of making it sound the same everywhere. Voicing is the process of “How should the sound system ultimately sound?”.In the absence of a viable alternative, I think MAPP is still the ultimate sandbox to experiment with these things while looking at data that you will run into in the real world.Vince Lombardi: Excellence is achieved by the mastery of the fundamentals.

This article Merlijn’s Subwoofer Alignment Method Will Make You Feel like a Jedi Master appeared first on Sound Design Live. Sign up for free updates here.

Loved this post? Try these:3 Phase Alignment Hacks to Make Your Sound System Tuning Easier Smaart® Beta: Will the new filter control in the delay finder help with your main+sub alignment? Dave Rat’s End-Fire Adjustable Arc Subwoofer Array Explained

Dave Rat’s End-Fire Adjustable Arc Subwoofer Array Explained

During my interview with Dave he explained a subwoofer array that he developed during a Blink182 tour. Here’s what it looks like.

[image error]

Here’s where Dave explains it in the interview, starting at 45 minutes.

This came out of the sub testing that I did, primarily on the Blink 182 tour and then finished or got farther on the SoundGarden tour. I tried multiple arrays and out of it I came up with this fanned array.

The way to make it is, find your zero point, your rear sub location, the center of the grille. I would just have someone step on a tape measure there or put a road case on it. Then walk out 6.25ft for a 45Hz maximum rear cancellation. Then I draw an arc with the string.

Then you would place along that arc the front radiating points. One, two, three, however many you want. The 0ms point is your rear sub. Set your front ones at +6.25ft, which is about 5.8ms.

I see, so if you soloed up any of those front subs, they should be arriving at the same time as the rear subs.

Yeah, so the concept is the sound radiates from [the rear sub] and travels 6.25ft to sum with the subs in the front.

The closer these are together the beamier it gets. As you spread them out on the arc, the wider it covers.

[You have to put a sub stack in the back equal to the ones in the front. Each stack has three.] It’s making sound that will actually cancel out everywhere else and sum in the front.

The theory

Dave’s design is a combination of end-fire and physical arc. The end-fire takes care of the cancellation in the rear and the arc controls the coverage width.

End-fire array: an array of multiple subwoofers, placed in a line, one behind the other, with a specific spacing and delay strategy in a timed sequence that creates forward addition and rearward subtraction.

Bob McCarthy, Sound Systems: Design and Optimization

The array achieves summation in the front by delaying the front elements to the rear, causing everyone to arrive at the same time. It achieves cancellation in the rear through delay as well (output processing + distance offset), except in the rear everyone is arriving late causing a chaos of phase relationships.

Physical arced arrays exhibit a coverage angle equal to the segment of the arc segment of virtual circle whose origin lies behind the array.

Merlijn van Veen

A physical arced array turns a line source into a point source. Where all elements were arriving at equal level and time on-axis, they are now steered outward with a virtual origin from behind the array. As arc angle increases so does coverage width as the various spatial crossovers move away from on-axis.

The design

How did Dave come up with the 6.25ft spacing?

spacing = ¼λ

spacing = speed of sound / frequency * 0.25

6.2778 = 1130 / 45 * 0.25

Dave’s design breaks some rules, which is fun. Normally we avoid a two-element end-fire array because it is limited to a single cancellation in the rear and then comes back with a nasty peak an octave up.

It is for this reason that if you design this array in Merlijn van Veen’s Subwoofer Array Designer, it will recommend high and low-pass filters at 29 and 60Hz, respectively.

[image error][image error]

With preferred filters.

[image error]The modelWide coverage

I haven’t tried this in the field, yet, but we can look at some models in MAPP XT.

I’ll start with the widest spacing to get the widest coverage.

[image error]

Here’s a prediction at 44.2Hz showing an opening angle of 176º.

[image error]

In the measurement viewer we have a nice F2B ratio of 50dB at 50Hz.

[image error]

But why 50Hz? I expected to see it at 45Hz.

It turns out that I spread the subs out so far that the distance offset changed from 6.28ft to 3.77ft from the rear. This changed the combined phase of the front subs to 150º apart at 45Hz and 180º apart at 50Hz, compared to the rear sub.

[image error]

I reset the placement and delay based on the outside subs instead of the center one and was able to shift the null down to 47Hz. Hurray!

[image error]Narrow coverage

Now let’s try the narrow coverage version.

[image error]

Here’s the prediction at 44Hz. Looks like it’s 10º more narrow than the previous design.

[image error]

Nice F2B rejection of 31dB at 44Hz.

[image error]An alternative?

Dave breaks some rules here, which is fun.

Never end-fire with just two elements. It’s a one-note-wonder on the back side. Use the gradient in-line instead (same physical, different settings).

Bob McCarthy

This make me wonder what an in-line gradient array would look like with the same design.

Gradient array: A cardioid configuration commonly used for subwoofer arrays with front and rear elements. The rear element is delayed and polarity reversed to effectively cancel behind the speakers.

Bob McCarthy

The gradient array has frequency dependent coupling in the front in exchange for broadband cancellation in the rear.

You can use the exact same speaker placement, with different output processing.

[image error]

It looks very similar to the end-fire at 44Hz, but is quite different across its operating range.

[image error]

Where we had a limited range of cancellation with the end-fire array, we now have broad-band cancellation with the gradient. You may be worried about the dip at 100Hz, but notice that that the expected response is already 20dB down, moving it into isolation if you are running a linear system.

What’s it for?

As we discussed on the podcast, Dave was looking for a way reduce LF interaction in the center of the audience and total LF energy behind the arrays.

Compare a traditional setup of left and right sub stacks…

[image error]

To two of Dave’s end-fire arcs splayed 90º apart.

[image error]

If you would like to play with these MAPP designs, you can download them here. Please let me know if you discover any improvements.

Dave Rat’s End-Fire Adjustable Arc Subwoofer Array

During my interview with Dave he explained a subwoofer array that he developed during a Blink182 tour. Here’s what it looks like.

[image error]

Here’s where Dave explains it in the interview, starting at 45 minutes.

This came out of the sub testing that I did, primarily on the Blink 182 tour and then finished or got farther on the SoundGarden tour. I tried multiple arrays and out of it I came up with this fanned array.

The way to make it is, find your zero point, your rear sub location, the center of the grille. I would just have someone step on a tape measure there or put a road case on it. Then walk out 6.25ft for a 45Hz maximum rear cancellation. Then I draw an arc with the string.

Then you would place along that arc the front radiating points. One, two, three, however many you want. The 0ms point is your rear sub. Set your front ones at +6.25ft, which is about 5.8ms.

I see, so if you soloed up any of those front subs, they should be arriving at the same time as the rear subs.

Yeah, so the concept is the sound radiates from [the rear sub] and travels 6.25ft to sum with the subs in the front.

The closer these are together the beamier it gets. As you spread them out on the arc, the wider it covers.

[You have to put a sub stack in the back equal to the ones in the front. Each stack has three.] It’s making sound that will actually cancel out everywhere else and sum in the front.

The theory

Dave’s design is a combination of end-fire and physical arc. The end-fire takes care of the cancellation in the rear and the arc controls the coverage width.

End-fire array: an array of multiple subwoofers, placed in a line, one behind the other, with a specific spacing and delay strategy in a timed sequence that creates forward addition and rearward subtraction.

Bob McCarthy, Sound Systems: Design and Optimization

The array achieves summation in the front by delaying the front elements to the rear, causing everyone to arrive at the same time. It achieves cancellation in the rear through delay as well (output processing + distance offset), except in the rear everyone is arriving late causing a chaos of phase relationships.

Physical arced arrays exhibit a coverage angle equal to the segment of the arc segment of virtual circle whose origin lies behind the array.

Merlijn van Veen

A physical arced array turns a line source into a point source. Where all elements were arriving at equal level and time on-axis, they are now steered outward with a virtual origin from behind the array. As arc angle increases so does coverage width as the various spatial crossovers move away from on-axis.

The design

How did Dave come up with the 6.25ft spacing?

spacing = ¼λ

spacing = speed of sound / frequency * 0.25

6.2778 = 1130 / 45 * 0.25

Dave’s design breaks some rules, which is fun. Normally we avoid a two-element end-fire array because it is limited to a single cancellation in the rear and then comes back with a nasty peak an octave up.

It is for this reason that if you design this array in Merlijn van Veen’s Subwoofer Array Designer, it will recommend high and low-pass filters at 29 and 60Hz, respectively.

[image error][image error]

With preferred filters.

[image error]The modelWide coverage

I haven’t tried this in the field, yet, but we can look at some models in MAPP XT.

I’ll start with the widest spacing to get the widest coverage.

[image error]

Here’s a prediction at 44.2Hz showing an opening angle of 176º.

[image error]

In the measurement viewer we have a nice F2B ratio of 50dB at 50Hz.

[image error]

But why 50Hz? I expected to see it at 45Hz.

It turns out that I spread the subs out so far that the distance offset changed from 6.28ft to 3.77ft from the rear. This changed the combined phase of the front subs to 150º apart at 45Hz and 180º apart at 50Hz, compared to the rear sub.

[image error]

I reset the placement and delay based on the outside subs instead of the center one and was able to shift the null down to 47Hz. Hurray!

[image error]Narrow coverage

Now let’s try the narrow coverage version.

[image error]

Here’s the prediction at 44Hz. Looks like it’s 10º more narrow than the previous design.

[image error]

Nice F2B rejection of 31dB at 44Hz.

[image error]An alternative?

Dave breaks some rules here, which is fun.

Never end-fire with just two elements. It’s a one-note-wonder on the back side. Use the gradient in-line instead (same physical, different settings).

Bob McCarthy

This make me wonder what an in-line gradient array would look like with the same design.

Gradient array: A cardioid configuration commonly used for subwoofer arrays with front and rear elements. The rear element is delayed and polarity reversed to effectively cancel behind the speakers.

Bob McCarthy

The gradient array has frequency dependent coupling in the front in exchange for broadband cancellation in the rear.

You can use the exact same speaker placement, with different output processing.

[image error]

It looks very similar to the end-fire at 44Hz, but is quite different across its operating range.

[image error]

Where we had a limited range of cancellation with the end-fire array, we now have broad-band cancellation with the gradient. You may be worried about the dip at 100Hz, but notice that that the expected response is already 20dB down, moving it into isolation if you are running a linear system.

What’s it for?

As we discussed on the podcast, Dave was looking for a way reduce LF interaction in the center of the audience and total LF energy behind the arrays.

Compare a traditional setup of left and right sub stacks…

[image error]

To two of Dave’s end-fire arcs splayed 90º apart.

[image error]

If you would like to play with these MAPP designs, you can download them here. Please let me know if you discover any improvements.

How to Estimate Delay and Level Offset Between Speakers in Your 3D Models

Save time in the field by presetting your speaker output delay and level offsets.

Here’s a model from a recent show where I estimated the level and delay for a pair of relay speakers and line of front-fils.

[image error]

If you know the difference in distance between two sources, you can accurately estimate their time offset, and therefore, the delay necessary to bring them into alignment. The challenge is finding the correct crossover point.

Drawing About Sound

Crossover (spatial): An acoustic crossover in a spatial domain, i.e. the location where elements combine at equal level.

Bob McCarthy, Sound Systems: Design and Optimization

Finding a spatial acoustic crossover point in the field is pretty simple. Once you have defined the on-axis (ONAX) point for source A and source B, match their levels, then walk in a line between the two points until they sound equal. Place our measurement microphone at this point, then use the audio analyzer for verification.

You can simulate the process in a modeling and prediction software like MAPP XT, but I have been practicing a quick offline method of drawing speaker coverage shapes and estimating their crossover points that you can do on a plane (or even with pencil and paper in 2D).

Here’s a recent show that I worked on using JBL VRX 932 speakers on stands. The distance from the speaker to the end of coverage is 61.66ft. I can divide this distance by the forward aspect ratio of this 100º speaker to find the coverage width.

61.66ft / 1.31 = 47.1ft

For more on forward aspect ratio, please read One Simple Tool to Find the Right Size Speaker for Any Space. These topics are also covered in detail inside of Pro Audio Workshop: Seeing Sound.

[image error]

This gives me a quick sketch of the coverage shape.

[image error]

For comparison, here’s a similar speaker’s prediction at 4kHz.

[image error]The Steps

Here’s how you would do this in the field with the audio analyzer:

Match solo ONAX levels B1 to A1.Find XAB (the acoustic crossover between A and B) between ONAXA and ONAXB where A1 and B1 match in level .Set delay.

Now let’s do those steps in our model with distance measurements.

Set Level

B1 level = 20 * Log10((distance from ONAXB to B) / (distance from ONAXA to A))

In our model that would be -2.4dB.

20 * Log(22.59 / 29.78)

You can drop that formula into google to verify it.

[image error]Find XOVR.

Find XAB at the center of their coverage pattern overlap.

[image error]Set Delay

B1 delay = (distance to A1 – distance to B1) * 0.9

In our example model that would be 24.17ms.

(48.01 - 21.16) * 0.9[image error]Field results

Once we got into the room the coverage shape of B1 changed due to an obstruction. This changed the level offset, but the delay was very close to my estimate.

Much of the front-fill processing changed because we replaced two of the 928 speakers with 932 models and were able to level set and delay them independently.

Will this work for subs?

Yes for delay. If you have followed Merlijn van Veen’s Relative/Absolute Method, then you already have a preset for the relative relationship of the spectral crossover alignment of your main and sub. Use your 3D model for the absolute step.

No for level. Low-frequency energy will enjoy room gain and I’m less confident that a distance measurement will help you estimate the level. If you try it, let me know.

Have you tried presetting your DSP using distance measurements from a model? How did it go?

This article How to Estimate Delay and Level Offset Between Speakers in Your 3D Models appeared first on Sound Design Live. Sign up for free updates here.

Loved this post? Try these:3 Phase Alignment Hacks to Make Your Sound System Tuning Easier How to Time Align Your Main to Your Front Fill Using Smaart Live IR What do I need to know about my speakers?

Dave Rat’s Simple Problem Solving Mindset for a Long Fulfilling Career in Pro Audio

Subscribe on iTunes, SoundCloud, Google Play or Stitcher.Support Sound Design Live on Patreon.

In this episode of Sound Design Live I talk with the president of Rat Sound Systems, Dave Rat. We discuss artistic solutions to technical problems, the best mindset for a finding work and a long fulfilling career, and the time Flea shouted in his face for missing an entrance.

I ask:

What are some of the biggest mistakes you see people making who are new to FOH mixing?What is the biggest mistake you’ve made on the job and how you recovered. From FaceBookRoshan Malim: Ask him about his sub woofers configurations and which is his favorite and why? And what is his most common sub woofer configurations for gigs? His ideas between flown subs and ground stack subs.Christian Michael Martinez: As an owner of one of the largest production companies, how did you cope with the possibility of failure in the beginning as a small shop? How do you cope with risk now that the company is a success?Maurizio M. D’Errico: Ask him about his technique of tuning a pa using headphones as a reference and if he still feels the same way about it since he made the YouTube video: How to EQ a Live Sound Reinforcement System. Craig Gordon: Balancing touring and family/health.Stephen Mink: Since he has some videos on YouTube about sub placement/patterns/alignment, his thoughts on where in a room to align flown and ground subs.Dave Gammon: Does he really see the M-Force driver as the futureGarrick Quentin: Has he seen or heard of anyone else not affiliated with Rat sound using the double hung array as he did with the RHCPs and perhaps any comments on the whole concept in terms of its popularity, or otherwise, within the industry.Davide Bonetti: does he need an assistant?