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[Abdul-EQ]

Abdul-EQ is normally informative and entertaining, this time he seems annoyed.
The April copy of Live Sound International arrived and the first thing seen is the advert on page 5. Abdul remembers when Lars had an endorsement deal and a hardon for the EV line array. That was many issues and a few years back. What, did he think we forgot? Abdul is no rocket scientist, in fact, he’s just a self-proclaimed King of Karaoke, but even a time-blind monkey can see the low coherence of Lars’ two conflicting positions. What happened? John and Helen pay more?  Maggie May is nearing sixty, maybe Lars got attracted to some new stuff and wants to embrace higher technology.

Abdul also has a question or two for Professor Alexander on the top of page 38.  If the reason that the drum fill runs at “arc” is to overpower the late-arriving energy of the main sound system at the drummer’s position, how does adding delay to the mains change this relationship for the better? The mains are already arriving at that position later because they are further away physically.  Adding delay to the mains may signal align things from the FOH perspective, but from the drummer’s perspective, the mains are now further away. (Physical distance and added signal delay) Unless the Professor has invented a negative delay, simultaneous arrival is impossible. If the Professor did invent a negative delay, why didn’t he use it to rescue Mary Anne and Gilligan or prevent Maggie May from aging?

During his attempt to surround the audience with a disappearing sound system, the author makes the mistake again.  An audience member that is closer to the stage sound needs a different signal delay time to achieve simultaneous arrival than an audience member who is closer to the speaker system. A person sitting at the acoustic center between the two requires no delay. If these delay time compromises exceed the 20 – 35 mSec Haas effect, distinct arrival times will occur. Venue size is clearly critical to the professor’s approach.

The Professor doesn’t understand a dynamic feedback loop?  Allow Abdul to explain.  Wife #1 pleads “ !#$% me again Abdul!”  Abdul increases the Time allocated.
Wife #2 screams  “!#$% me harder Abdul!”  Abdul increases the Energy expended.
Wife #3 demands “!#$% me faster you Sand Devil!” Abdul increases the Frequency at which he operates.
Constant monitoring and adjustment, that’s all a dynamic feedback loops is.
Abdul suggests a more liberal arts college.

Abdul-EQ

[Guest]

[Ivan Beaver]

I agree.  I have aligned many true LCR cross matrixed systems.  It doesn't take long to realize that is easy to get it right for 1 person, but to get it right (or close) for several thousand people at the same time is another issue.  The more you make it right for a single person the more problems it causes for other people a distance away.  I usually walk 5-6 miles (I wear a pedometer) during an alignment.  It usually takes 5-10hrs.  This is after using 10 mics spread around the room to speed up the process.  A misalignmnet results in comb filtering/echo (multiple time arrivals).

This is not something you do on the fly-unless you are only interested in your seat-and not the sound for the people that paid to get in!!

I also loved the part that states that only 1.6K bounces off the back wall and 3.15K bounces off the stage rear wall (if it is close enough).  Do not other freq bounce off walls?  It is nice how he isolates the whole audio range down to a problem freq.

I still don't get the reason for the mics in the back of the cabinets. Wouldn't the sound out of the back of the cabinet override any sound that comes from the rear of the hall. And how clear will the sound be with the cabinet blocking all the highs?

I also install variable room systems and it takes a lot more that what he suggests to get that right also!

Sounds odd to me.

Ivan Beaver

[Sebastiaan Meijer]

Dear Abdul,

But.... if you spend more time @wife#1, more energy @wife#2 and you need to come more often @wife#3....
How do you keep your camel fit for the races? The poor animal must be exhausted from all the trips between tents.

Dynamic feedback loops smoke camels.

S.

[Guest]

[Abdul-EQ]

I still don't get the reason for the mics in the back of the cabinets. Wouldn't the sound out of the back of the cabinet override any sound that comes from the rear of the hall. And how clear will the sound be with the cabinet blocking all the highs?

Mr. Beaver,

Normally Abdul would be inclined to riff on your name.  You know, make some Clever joke or say " Leave it to Ivan to correct the Professor." But no, not this time because Abdul has broken bread with you, and you deserve better.

Abdul did not address the author's artificial sweetening technique of the back of box mics; he'd already had his fill of empty calories. In addition to your italicized questions, Abdul wonders why a condensor mic is important. Certainly not for the extended high frequency response that the author avoids. The proximity of the microphone to the speaker box dictates that the sound coming off the speaker will dominate at the microphone voice coil. The room sound is down ~40dB there or close micing never existed. Abdul doesn't care who the manufacturer might be. At the suggested 1/8" from the speaker box, the speaker dominates. What do you suppose the importance is for NOT using EQ(no relation)on these mics? The nasty phase changes that an equalizer introduces? Wouldn't want to degrade the signal path now would we?

Abdul can't wait til next month when we see how this works in a real live working situation.

Allah bless you and your precious family,
Abdul-EQ

[A Man]

It is the April issue.  

Methinks there is some serious chains getting pulled.

-if not-

I'd bet 99 out of 100 monitor mixers would say that everything coming off the back of the mains sounds like ass.  

[Dave Stevens]

I just read that on the plane...

Even if it was an April Fools gag it wasn't funny.  

Dave

[Ivan Beaver]

Believe me I have been tempted----. My boss has suggested that I do a seminar exposing all the problems and the solutions taken to MINIMIZE the problems (with LCR)-they will not go away.  As in all things audio-everything is a compromise of some sort-size/performance/price etc., but not I am so busy at work-among other projects.

Ivan Beaver

[pav01]

Just how seriously can you take an argument between Mr Beaver and Mr Camel ( toe ) ??

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