Archive for the ‘Sound Systems Book’ category

Sound Design Live eBook

July 25, 2013

I recently wrote the forward for an eBook that Nathan Lively has published called Sound Design Live: Build Your Career As A Sound Engineer. It’s a great read and I’ll include the forward below.

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sound-design-live-ebook-coverAudio engineering technology has changed, but the work is still all about connections. Not through CobraNet®, Dante or AVB but rather the personal connections of telephones, email, social media and old-fashioned face to face. Connecting to creative artists, crew, managers, producers and audiences. If you are already in this field you are somewhere in this interconnected network. If you are wanting to get involved, welcome to the ultimate work in progress. This book is all about connections and why they are the most important, valuable and motivating forces in the industry. Nathan Lively plays the role of network hub and monitors traffic in this book to give you a glimpse into the absolutely real experience of our peers and mentors in this trade. The voices in this book have vastly different viewpoints, passions, and experience. Artists who use technology for self-expression, technologists who thrive on being a conduit for artists to reach their audience, and folks who have worn many different hats. If Nathan had brought them all together in one room to discuss audio, there would be at least as many passionate disagreements as points of concordance. Two points they would all agree on are the importance of having a passion for this field of work and attention to networking and relationships. So much of this field is serial monogamy, and therefore we must be careful to maintain good relationships, not burn bridges and keep that little black book up to date with all the folks you might want to see in the future. This book examines the relationship issues that are so important for getting into, and staying in, this business.

Nathan’s choice of speakers and topics provides a mix of information and experiences that I have not seen collected in one place. The viewpoints are refreshingly honest and free of the laundry lists of gear that characterize 90% of words written about this field. These are not all superstar designers with mega-million dollar projects. Dive bars, home studios, educators, starving artists and manufacturers are here as well. The contributors are very real people in whom it is impossible not to see a part of yourself, just as much as it impossible to not find a viewpoint that you had never considered or understood before.

Nathan’s “Sound Design Live podcasts” have brought these people’s voices to the internet and will continue to do so in the future. Here and now is a collection of assembled wisdom and experience that I believe will open your mind to the many ways you can expand your role in the audio professional network.

Sound System: Design & Optimization hits 10,000

September 13, 2010

Thanks for your support

I am grateful to announce that Sound Systems: Design & Optimization has reached the milestone of 10,000 copies sold. Around half of these are the English language editions and the remaining half split equally between the Spanish and Chinese language editions. Work is currently underway to translate the 2nd edition into Chinese. I want to extend my thanks to everyone that has supported this project, either by buying the book, promoting it to others, or helping me write it. Thanks especially to my editor Catharine Steers at Elsevier, all of my peer reviewers and those that contributed photographs and perspective pieces for the book. Thanks also to John and Helen Meyer, Gavin Canaan, Mac Johnson and all the staff there that continue to support my educational efforts through their sponsorship of my seminars and to all who have taken their valuable time to attend them. Thanks also to everyone at LiveDesign, Rational Acoustics, TC Furlong, and others that have helped promote this book.  Also to Ana Lorentz for translation of the Spanish Edition and to Magu for his help in that effort. Finally my highest gratitude goes to my wife Merridith who negotiated the deal and was one of just two people (along with Thorny) to read the whole book during its development.

When this was written I felt that less than 1250 books would be a failure, and anything more than 2500 would be a success. Reaching 10,000 in less than 4 years is far beyond my wildest dreams.

So thanks a million, I mean a ten thousand.

Sincerely,

 6o6

 In case you are interested: Here is what I did with the proceeds from the book: I crossed back over the art/science line to a 1978 Gibson Johnny Smith, and a 2009 Breedlove Bossa Nova.

1978 Gibson Johnny Smith

Breedlove Bossa Nova

New York Trainings – Updated with Pics

May 19, 2010

I am in NYC this week for two rounds of classes: SIM3 training in Brooklyn and the Broadway Sound Master class on the NYU campus in the East Village. The SIM class is at City Tech in Brooklyn – which is where John Huntington teaches. We have several of his students joining the class which is really nice. This trip marked a first for me – even though I have been coming to NYC quite regularly since 1984 this was the 1st time I ever set fot in Brooklyn. We arelocated over by the legendary brooklyn bridge and I can see it from the school – so hey – I can add another borough to my list……Manhattan, Queens – been 2 places there – La Guardia AND JFK – wow, and now two places in Brooklyn – City Tech AND Peter Luger – the famous steakhouse.

We are halfway through the class and pretty much right on schedule. Looking forward to the BSMC this weekend – always a great learning experience for me

****** John Huntington was kind enough to take some pics of the seminar.

6o6

Off to Mexico for AES and SIM3 Training – Updated

April 25, 2010

I have been busy putting together new material for SIM 3 training, and AES seminar and the upcoming Broadway Sound Master Class. You have seen some of the work in progress below, but I have had to push to get things ready for showtime.  Sorry for the delay in getting more things posted and for my lateness in response to Goran. Just pushing it right now – LOTS of really good stuff coming- phase circles galore but priorities………..

AES Expo

I was invited to give a talk for the AES at the Sound Check Expo in Mexico City

This is a big audio trade show in Mexico City. Lots of  levels of gear mixed together: Pro Audio, Music Industry Audio, Guitars, Pianos, Disco lighting , and the most popular event was getting the autograph of a hot young girl singer. I am sorry but I never made it to the front of the line. :-(.

I did a talk for about 1.5 or  hours and it was like giving a speech at the United Nations. There was a faint spanish language echo in the room when I spoke, about 500 ms delayed. It was a translator in a booth at the rear and everybody in the audience was listening on headphones. Wow, this guy was fast – and good, because I even got a few laughs at my jokes. I remember doing a translated seminar once in China. 4 days without a single laugh – until I tripped and fell down on the stage – the crowd loved THAT!   OK back to Mexico. The lecture was very well attended and it was a great honor to have so many people there. We covered alot of interesting topics including subwoofers steering and fun stuff like that. I was told that this was the best attended training session of the convention (about 120 people) and that felt really good. If only I could have gotten the singer girl to join me on stage we would have REALLY filled up the place!

Here are two pics from the seminar. The first one shows me at the podium. I don’t remember the bubbles floating around the room, but you can see them in the picture. The second one shows the view in the room.

AES Sound Check Expo

SIM3 Seminar

 Next on the agenda was Meyer Sound Mexico where we held a SIM3 Training. It was the usual 4 day session, but in Mexico City the sessions are marathons. Typically we go from 10 am to 7pm, but two of the days we went past 9 pm. The Mexico city schools are some of the most interactive of all the schools I do. The students are sendiing up a constant stream of interesting and challenging questions and we cover SO MUCH material. Sometimes the order in which we cover them is a bit crazy, but we cover TONS of topics.

Working with me on this seminar was Oscar Barrientos and Mauricio Ramire(el Magu). These are expert teachers in their own right so it is great to have them to translate and enhance. My typical style, when doing a translated seminar, is to (try) keep my talking short, to make quick switches to the translators. With these guys, because they know the subject so well, they can follow the concepts and even expand on what I say when they move it into Spanish. This helps speed things along alot – because typically a translator has no audio knowledge, does not know the terms, and certainly does not know FFT analysis. (In Korea once we had a translator QUIT at lunch time the 1st day – because she was too humiliated by all the students telling her she was translating all the audio words wrong. A student, Sean Cho, took over the job and saved the seminar).

Most of the students had been to Magu’s and/or Oscar’s training courses before and a few (Eduardo Brewer from Venezuela and Jorge and Juan Carlos Yeppes) had even been to my course before. It is the ultimate honor for me to have engineers return to my course.  The advanced level of the students helped us to move along at a very fast pace.  I am always very grateful about the way i am treated in Mexico. They are SO GOOD to me.

I also had the honor of meeting Luis Pinzon. He is the only person I know with 3 copies of my book – 1st & 2nd edition ingles, and 1st edition espanol. I happily signed all 3 for him. I wish I had brought a Chinese version to give to him. That would have completed the set!  . Luis also gave me his cable checker – which is quite amazing.

I was taken to some really nice restaurants by Antonio Zacarias and also  we went for Tacos to El Charco – which I highly recommend.  Also went to a Chinese restaurant in a shopping mall near Meyer Sound Mexico – I DON’T recommend this place, unless you want to die.  Funny though ….A week later I had Mexican food in China – The Mexican food in China was better than the Chinese food in Mexico, but Mexican in Mexico and Chinese in China worked out the best.

So here are some photos from the Mexico seminar, taken by Eduardo and Hermes. I think I have the names right on the class photo – if not help me out please. Also if you have some others – please send them to me.

Thanks for inviting me to Mexico, and I hope I can come back soon —actually I WILL be back in Mexico this Novemeber – but it  a cruise vacation – so I won’t be working 🙂

Until next time,

Hasta luego y Buena Suerte

6o6

 
Mexico SIM3 Class 2010

6o6 is getting some hands on experienceNow we know who was reading email during class

Yes this is supposed to make sense..........

Magu, Oscar, Paco and 6o6

Eduardo, Magu, Hermes, 6o6, Oscar and the bald guy

6o6

Uncoupled Array Design: Beginnings and Endings (Updated)

March 28, 2010

** Update:  A downloadable version of the calculator to do this work is available (courtesy of Daniel Lundberg). Go to the bottom of this post for preview and instructions. 

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When a coupled array is assembled, its operating range is limited primarily by its power capability. Even very large arrays will congeal fairly quickly and once they have joined together let no phase tear them asunder. Wow! Not often that we can work hard-core religion language into speaker array theory (not to say there is not a lot of mysticism out there in line array theory land).  So coupled arrays, once joined, once fully formed will maintain there shape over distance, finally either running (literally) out of air, or into the wall.  

Uncoupled arrays are quite the opposite. They can’t wait to destroy themselves. The battle begins with each speaker owning  its piece or real estate close by, in front of it. As we continue forward we have a happy meeting with the neighboring speaker’s response. They greet with an in-phase handshake and we have a crossover, known as the unity line.  At this point the speakers are working together and the line that runs from speaker center to center (through the crossover) is approximately unity gain. This is exactly what we want to happen – an extended line of unity gain, wider than a single speaker. Ideal for frontfills, underbalconies, parade routes, racetracks and more. This is both a happy beginning AND a happy ending.  How so? The beginning part is obvious, but the ending part…………well what I mean here is that this beginning is the best response we will get. It is all downhill from here as the more distant areas directly in front of each speaker no longer have sole ownership of the coverage. The others speakers are spilling in and they are arriving late. VERY late in acoustic terms. The displacement between the speakers (a factor that is large in an uncoupled array) now creates a very rapidly changing variation of time offsets between the elements. The result is combing that moves rapidly down in frequency and becomes stronger with each step we go deeper into coverage.  

How far can we go before we throw up the white flag and surrender? One could evoke a variety of subjective answers such as: until it sucks, or until I can afford another set of speakers to take over etc., but these are not very satisfying to me. There is a verifiable milestone: three’s company. When we reach the point where the entire length of the coverage line is within the pattern of three sources we have reached full immersion into the combing. Three is a magic number. With three sources arrayed along a line, or an arc it is impossible to find a location that is equidistant to all three. This guarantees two or three arrival times from speakers operating within their coverage  angle. That is the fight I was talking about before. The only way to stop the fight is to drown it out with another much louder speaker – like a mains to take over for your frontfill, or stop it – like a back wall for your underbalconies.  

In my book I go through a set of design calculations for uncoupled line source and point source arrays. The variables are the coverage shape of the speaker (The Forward Aspect Ratio/FAR), the spacing, and the splay angle. From these we can determine where the coverage will start (D unity) and where the coverage should end (D limit). If you know the speaker and where your audience starts, you can determine the spacing, and where you will need to connect to the mains. If you have fixed positions you can get the right speaker model etc.  

An example reference chart using a 80 degree speaker in an uncoupled line source is in the book.  This shows nicely how to solve for this particular model and then one can refer back to the FAR chart to get the angle/FAR conversion for other speakers.  

Uncoupled line source design reference for an 80 degree speaker

Design procedure for the same speakers as above

Another example reference chart uses a 90 degree speaker in an uncoupled point source source in the book.  In this case the splay anglwe variable is added to the equation.  

Design reference for 90 degree speaker in an uncoupled point source array

Design Procedure example for a 90 degree speaker

It is not possible to put an XL file into the book and not practical to give a separate chart for each speaker angle/spacing etc.  but folks that bought the book don’t have a working calculator/spreadsheet that they can go to on their computer so I was in the process of making one for the blog and then Daniel Lundberg contacted me with his calculator based on this same concept. Whereas mine was derived from observing the trends and behiavior of many, many, array interactions, Daniel’s goes to the heart of the trigonometry involved.  

So over the past few days I ran through some different models of speakers athdifferent angles and spacing to check for consistency between a) my published values derived through observation of other speakers at other angles  

b) Daniel Lundberg’s values derived through trigonometry and geometry  

c) what we can see on the MAPP plots now  

The good news is they are all in very close agreement.  The largest discrepancy is in the limit values for the longest range, and even these are relatively close.  

Comparison of observed and mathematically derived values 45 deg speaker with 4m spacing and 0 deg splay 45 deg speaker with 4m spacing and 4.5 deg splay

45 deg speaker with 4m spacing and 9 deg splay 45 deg speaker with 4m spacing and 13.5 deg splay

45 deg speaker with 4m spacing and 18 deg splay

45 deg speaker with 4m spacing and 22.5 deg splay

  

Here is what the downloadable version of the calculator to do this work looks like (courtesy of Daniel Lundberg). You can have a copy of it. Free. 

HOWEVER, the security rules of this blog host prohibit me from posting an XL file. 

Therefore, if you want a working copy of this calculator, you will need to send me an email request to bob@bobmccarthy.com. If you think this is just a trick to get you on my mailing list…………

 

Phase alignment of spectral crossovers

March 11, 2010

This is a continuation of the impulse response subwoofer thread. Here are some screens from Sounds Systems: Optimaztion and Design that deal with phase alignment of crossovers.

The figure above shows the phase responses brought together between sub and main.  The crossover is not steep and therefore the phase response overlap over a wide range.

The LF and HF components of a 2-way xover

The combined response of a 2-way xover

Line Array Gain Taper (Breaking the Line II)

March 10, 2010

After Bob Gardam’s comment on Breaking the Line I decided to give a quick go of the hypothetical scenario I had proposed in my reply:

12 boxes,  6 @ 2 degrees @ 0 dB, 3 @ 4 degrees @ -2 dB, 3 @ 8 degrees @ -4 dB.

I made screen dumps of 3 scenarios:

1) 0,-2, -4 dB taper – the system as it would be if operated below limiting

2) 0, 0, -2 dB taper – the system as it would be if the top section only was limiting

3) 0, 0, 0 dB taper – the system as it would be if the whole system was limiting – or if there was no gain tapering

As expected the compression reshapes the HF range most noticeably. The honed agular shape – longer throw for the uppers – becomes rounded so that the relative level in the near areas goes up.  This is most easily seen in the 4 kHz response because there is minimal fingering, but is also present in the 8 k Hz response.

The 1 kHz response carries on the trend in a similar – yet reduced fashion. Notice that the main frontal lobe is barely affected. Waht you see is an increasing bulge in the underside heading toward the near seats.

The 250 Hz response requires a very careful look to spot the changes. Two things are happening. As the taper is reduces by compression the additional coupling of the lower boxes steers the main lobe downward by a whopping 1 degree.  Not exactly a game changer. People who can hear that in their system should check out the products of Acoustic Revive.  The other change is that the beam has narrowed very slightly. This can be seen by the markings I made of the original shape. The mechanism causing the narrowing is the same as the downwaqrd beam steer – increased summation causes both.

So here is your choice – loud HF in the front ALL the time, or only when we drive it limiting. Bear in mind also that the limiting simulated here is a brick wall. Actual limiters will be more forgiving so results in the field would be somewhat LESS than that pictured.

6o6