Right!!!

So cool and thank you!

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very cool, thanks for posting. Glad the info can be helpful

Awesome!!

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Awesome and thank you!

Awesome and thank you!

Thank you thank you!

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keepin mind that temp impacts high frequencies more. and the longer distance increases the impact as well

Interesting. Turns out humidity doesn't impact sound very much but heat affects it significantly. One of The issues that he creates is when you have an inversion layer. That is where you have cold air sitting on top of hot air which causes significant refraction of sound off of the hot air if the sound system is radiating from a space that's up in the cold air. Sounds like what happened in your event was you lowered the PA such that it was radiating sound from within the hot air and dropped it out of the colder air above. Perhaps it was an air conditioner or it was colder outside and the roof was radiating lower temperatures creating the inversion layer

@DaveRat yep, that's the conclusion I had to drop it. Still wasn't ideal, but it was better. Figured the hi end dispersion angle could allow a better result about 3 feet above head height. Temperature definitely. But with humidity, those fine moisture particles absorb energy too.

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Interesting. Crisp nights can give that sparkle. But seems too cold gets dull again

+G Carttar where does the HF HF go? Good question. In the demo it moves up a to the sides as well. So of smeared out an away from the heat. For a rock show, I believe I smears upwards a unevenly at various angles.

Exactly!

Thank you Kevin for the props!

Interesting. Soundchecks in hockey arenas with wood over the ice floor and the heaters on does have the sound bend down and the reverse direction for show time

Yeah, KZfaq deleted 15,000 comments on my channel in a screw up. Hope I will be able to get them back and thank you!!

+theheilious Shouldn't even be an issue if you can fly your mains over the front of the audience, angled down at an angle sharp enough to not be affected. For a larger audience, fly more speakers farther back, and delay the signal going into their amps, so that their sound arrives in phase with the sound coming from the over-stage mains.

+Matthew Morgan ha yes, Festool tracksaw! Just go go new jigsaw with circle cut adapter. Festool I night and day better than any other tools.

you can say that again! I just got a jigsaw, router and sander for christmas. Santa went way overboard this year.

if you dont have the dust collector already I suggest that purchase. It's what really makes the tools stand out.

+Matthew Morgan yes, have pretty much a full setup with table and chop saw. All about building quality stuff very fast

Good ears and yes, cold will tighten up the cones and and drop some low end till they warm

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The mest bags absorb the lows.

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+Rosie The Band Thank you for commenting. The issue as I see it is that acoustic spaces are constantly changing. Yet test and tuning methods are primarily structured to 'set and forget'. We tune a room and then the audience shows up, the temperatures change and many aspects of the room sound change while other aspects stay similar. The floor reflection tends to be wide bandwidth, distinct and intrusive whereas the effect of the thermal layer from an audience tends to diffuse and dissipate high frequencies more than lows. I would say the value is using this knowledge to minimize wasting time tuning aspects of a system that will drastically change over the course of the show and focus on implementing methods to measure and easily compensate for the changing aspects in real time.

or hook up a monitoring system that adjusts your cabinet DSP in real time

mac rondo and what would that be?

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It's interesting to sort through these physical phenomenon and find which aspects impact us in relevant ways and which aspect we can ignore. I co wrote a paper for the AES society describing how sunlight on audio horns can alter the dispersion of the horn.

+theberndog it is is combination of temp differential, PA height/angle and distance among other things. I would always maintain an awareness of temp issues, and tur tur room heaters when possible. possible. Carry a laser thermometer gun with me an measure the room temp throughout the show.

Sound tends to refract when encountering a temperature differential. The more drastic the differential and the longer distance the sound is traveling while encountering the differential, the more sound will bend away from warmth or toward cooler air.

Hmmm, thats a fun stretch connection. The tunes need to warm up and stabalize to pass sound. Probably more like needing to defrost soup before you can stir it. Anyway, the impact of heat on sound in air is different frome the impact of heat in sound in wires.

Actually no. Outdoor festivals, warm ground will extend the coverage and at night coverage areas reduce to shorter distances. Heat is heat, it does not know if its inside or out

Do a search for my AES paper on heat and horn dispersion that I did with Mario DiCola 🤙

@@DaveRat i have to pay to read all the paper . the video i get the idea and conducted same test in my room . often my room THX cinema , 26c and that's with some of the processors switched on . i placed the heat-gun "paint stripper" off axis to the projection at-screen , near the HF horn JBL 2380A JBL CD 2445 . i used cable tie to hold the heat-gun to microphone boom lol . you could update on this test as it was 2015 . i tied air conditioner , but tricky and not messing with it as don't want damage it . was going to use bag of ice-cubes then maybe do smoke fog machine video with laser projection beams with a movie . the heat-gun test will suffice . my video on it be up soon . dave , keep up the science tests they are good .

Love that, yes test

You mean like fiberglass in the wall absorbs high frequencies of course. Except the fiberglass still hears all the high frequencies that it's absorbing How come the people can't hear the high frequencies they're absorbing?

@@DaveRat Certainly they can still hear the small amount of the overall speaker output that is coming at them directly, and if it were possible to focus the entire speaker output on their ears like a laser beam, nothing would change in regards to the size of the crowd at all. But what you have failed to consider is in an empty room that listener would also be hearing a tremendous amount of reflected sound as well. You could fill the remaining area around a single listener with (cold) sound absorbing battens, and I assure you the effect would be the same as having a crowd of hot sweaty people around them.

​@richmond4471 Air temperature changes air pressure sound is entirely dependent on pressure Rising air will reflect pressure waves Maybe it is not the entire equation but it surely plays a large part in it Now the fact that the heat gun creates a layer of air that is moving might be reflecting away the sound waves and it might not be the heat of the heat gun at all

Have you watched my video where I use the flames of a gas stove to do the same thing? When I used to do my seminar and travel around the world talking sound, I did a demo with a hot plate where I shot a speaker across the top of a hot plate and put a mic on the other side of the hot plate and as the hot plate increased in temperature the sound of the mic became noticeably dollar and dollar. I actually did this demo for a namm show presentation as well but for that I used a bunch of tea candles and a speaker shooting over them and a mic on the other side that was run into the speakers the audience could hear. When we supply sound systems for large festivals like Coachella, one of the issues we face is the temperature of the ground changing from the hot sun to the cool evening. The warmth of the ground actually refracts the sound such that the coverage distance is increased by hundreds and hundreds of feet and as the ground cools the coverage does the opposite and contracts. Nothing I'm presenting here is a mystery or unknown. The fact that sound refracts away from heat is well known. What I'm pointing out here is that phenomenon has a real world impact on the coverage of sound systems in the real world.

@@DaveRat my point was not to refute your point my point was to answer to him I have been doing it long enough to know that your point is correct

+vainwretch Pointing a speaker over the burners on a gas stove works.

+vainwretch HF reflects on smoke or haze aswell.

Actually pointing a smoke machine in the sound path has no effect. Using a spray water mist has no audible effect either. Holding a hot frying pan does have an effect. Try it! It is surprising how much heat has an effect compared to other things.

well i thought i noticed it. allthough the room itself was 55+celcius hot and steamy. and a lot of fog. but when the firefighters were outside , we had to turn off the hazers. and i thought it really had a effect regarding the HF. i thought so because of the heat, the the moist and haze fluid which is more dense. dont know! it made sence since at the time. i had to cut the HF with my lovely avalon instead of pushing it.

because it was still 55+c afterwards but no smoke. and i had to push the hf when it was hazy

+Shad Chollack (soundbarrier) hello Chad, maybe look at an Audix TM1 RTA mic, they are not too expensive and work well. if you call over to Rat Sound and talk to John Karr tell him know know he'll hook you up with bette prices than we are allowed to advertise or use on our Web store 8053830777

THANKS ALOT MAN! also i did have the dbx and the behringer rta mic, are all brands pretty consistent with same measurements.

+Shad Chollack (soundbarrier) For RTA/analyzer mics it is not overly difficult for a company to make a mic that has a flat response or at least very close to flat. Plus it does not really matter that much if a mic is slightly off of flat as because speaker response and room response tend to have variations from flat so much larger, that the tiny variations even a cheap mic has, are not really an issue. That said, the more important advantages of a higher quality analyzer mic are max spl, noise floor and mic to mic consistency. Cheaper mics can distort at high levels, especially at low frequencies causing erroneous readings. When measuring very low levels, cheaper mics can have internal noise issues that distort data. And also if using multiple mics, cheaper mics are less likely to be accurately matched in level and response.

THANKS FOR EVERYTHING. HOPE I CAN CHAT WITH YA ANOTHER TIME!!

Oh my, lots of worry and rules! Well, since airports, races, fireworks, an open car window on the freeway, a monocycle, going fast on a bicycle, snowboarding fast, audience cheering at any sporting event, and too many other things to mention all exceed 90 db, perhaps all of those things should be absolutely avoided, right!! As far as taking active control over the venue temp to optimize the audience experience vs just leaving it set wherever the local human thought was a great idea for the last hockey game, I would say that skilled attention to making things as good as they can be vs trusting someone that does not have the shows best interest at heart, is preferable, But who am I to say, its not like I have ever done some of the largest rock shows on the planet and mixed for for 40 years. Oh, wait....

@@DaveRat just wear earplugs when there are dangerous sound levels my dad could not handle his level of tinitus anymore and well lets just say he passed away

@@DaveRat sorry abou my comment i was probably tired an i have a mild case of hypochondria

All good. Balancing risk and reward is a challenge we all approach differently.

@@DaveRat yes i usualy eq my music so that i can play it at lower volumes but still sound great becuase if i use my big tamonn speakeers outside neighbours might otherwise get pissed off so i run my system mostly indoors witch has it pros and cons including reverb and smaller spaces get more sound at lower volumes so constantly adjusting eq and volume settings to make sure nothing gets to loud but it also is not to quiet

There was a link where you are running down your rig set up for RHCP in 2016 and giving your philosophy of sound engineering, I watched it. I don't know much about cabinets or effects just the basics on waves and interference, but I found your interview really interesting. I just thought I'd come back and say thanks for making the shows the best that they can be for whatever band you're with. You clearly care about the synthesis between the band and the crowd. Next time I'm at a show I will definitely pay more attention to the engineer booth, and hopefully I catch one of your shows.

I did another vid, I think it's on my Instagram where I shoot a speaker over a gas stove burner and have an RTA and mic on the other side. You can clearly hear it without the heat gun noise

To explain it further the heat forces the particles of air to expand from one another which makes the higher frequencies die quicker .

You aren't nearly as smart as you think you are. But Dave is.

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