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Hey guys what's up? Another tech question, what kind of mid air SPL readings do you think they reach at these shows? Are we talking open air past 150dB barrier (not near the ports I mean in audience). If so that's pretty nuts... Thanks!
 

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Yeah that's what I was thinking, I'm oldschool guy though so to me the 130's is needed and 140's sweetspot and satisfies, 150's nuts, 160's top fuel dragster crazy (loudest I've ever heard was Orion Demo van in 2001 that supposedly did low 160's (on old AC SA3055 w/SPL-180 mic so....) and I was scared). 170's I'm terrified of lol and I love bass music its one of my favorite genre's of music. Open air 130's though is insane, so if they're in 140's in the standing waves its got to be a beautiful experience!!! Probably sort of like when I heard a Clarion SRW8000 (32" Thunderdome) in person on 300 WRMs...def not meter happy...but an experience I'll never forget it just moved your shirt, insides, the drywall was creaking, wonderful!
 

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Discussion Starter #44
Some random observations:

I've been to a series of SPL events, and they're *nothing* like a good PK Sound system. At SPL events the sound is mostly contained in the car, so the experience at those events feels a lot like watching a locomotive going past. You can *hear* that it's loud but you don't get that 'punch in the chest' effect that you do at a PK show

I ran a spectral analysis of some dubstep tracks, and I think I figured out the "PK magic." (data is here: PK Sound CX800: 95% efficient?? - Page 12 - diyAudio) Basically a lot of these tracks have deep bass with no harmonics. I think the lack of harmonics is basically the secret sauce here.

Here's how this works, bear with me if this makes no sense:
In conventional music, there are lots of harmonics from the instruments themselves. For instance, when you play 40hz on a bass guitar, the harmonic at 80hz may be 75% as loud as the fundamental. And we hear high frequencies a lot better than we hear low frequencies. Due to this, the harmonic may "sound" louder than the 40hz fundamental.

Now if you strip out the harmonic, you can play the fundamental really really really loud without making everything sound muddy.

Take a look at my analysis of that Bassnectar track and you'll see this. The bass is TWENTY ONE DECIBELS louder than the rest of the track.

Back in the day, I remember guys would EQ their stereos so that it was all bass. But that sounds muddy fast, because of the harmonics

But strip out the harmonics? Then you can go nuts with the bass level.

To give you an idea of how insane it is to have twenty decibels of extra bass, if you were giving your midrange a hundred watts and you wanted to get your subs up by twenty decibels, you'd have to dump ten thousand watts into your subwoofers. And that assumes that they're the same efficiency! Which they usually aren't.

If the subs are just three decibels lower in efficiency, you'd have to put 20,000watts into the subs and 100 into the mids.



Now, obviously a lot of people will say that drum and bass had lots of bass before dubstep was around. But I think that D&B and rap had harmonics in the bass. This is for a really simple reason:

Drum & Bass and rap was largely based on sampling in the 90s. So the music was electronic, but it was sampling real instruments. (Which have harmonics.) Even old school electronic music from the 70s and 80s had harmonics, because a lot of the synths were designed to imitate the sound of real instruments (which have harmonics.)

IMHO, this idea of just using pure sine waves for bass is largely a product of everyone getting their asses sued off for sampling. But one way or another, we now have a lot of electronic music that's completely lacking in harmonics, and THAT allows them to crank up the low frequencies to an earth shaking level without it sounding like mud.

 

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Great post man, makes perfect sense! The stuff I really dig (DJ Magic Mike, Bass Mekanik, Techmaster PEB, Beat Dominator (mekanik's alias early on in 90's), Bass 305, basically all the "oldschool" Miami and Euro bass stuff, seems to be mostly pure sine tones (fundamentals as you just taught me) with not much harmonics. That's something I always loved was lack of harmonics in the bass. If there's a song with sine wave bass sweeps and drops I'm all over it, (must have equally great treble and mids to show off the highs). I'll have to check out these guys I might like them.
 

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Discussion Starter #47
Hey guys what's up? Another tech question, what kind of mid air SPL readings do you think they reach at these shows? Are we talking open air past 150dB barrier (not near the ports I mean in audience). If so that's pretty nuts... Thanks!
I did some fairly intense sims on the PK boxes over at the diyaudio thread, and the conclusion I came to was basically that they go a little louder and a LOT lower than boxes did in the 90s.

So it's not so much that your ears are getting blown out, it's that you're getting massaged with so much deep bass that it feels like something you've never experienced outside of a car.

If you've ever been inside a car when it was playing some deep bass and the subs were sucking the air out of your lungs, it's kinda like that.

Here's some calculations:



The rig at the Full Flex Express had something like sixty subwoofers.
Each one is good for 130dB at one meter, running at their max.
The calculator at sengpielaudio.com says that with sixty of those on tap, that gets you 128dB at ten meters. (about 30ft.)
This number doesn't make sense to me. As I understand it, that number should be 156dB, but maybe I'm missing something.

It's a real p.i.t.a. to get loud, and going from sixty cabinets to just six cabinets gets you 136dB. (This assumes that going from six to sixty cabinets gets you ten decibels of output, and multiplying the power by ten gets you another ten dB.)
 

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Discussion Starter #48
Great post man, makes perfect sense! The stuff I really dig (DJ Magic Mike, Bass Mekanik, Techmaster PEB, Beat Dominator (mekanik's alias early on in 90's), Bass 305, basically all the "oldschool" Miami and Euro bass stuff, seems to be mostly pure sine tones (fundamentals as you just taught me) with not much harmonics. That's something I always loved was lack of harmonics in the bass. If there's a song with sine wave bass sweeps and drops I'm all over it, (must have equally great treble and mids to show off the highs). I'll have to check out these guys I might like them.
The funny thing is that DVDs trump all of these guys. I used to have a giant 10hz tapped horn in my bedroom, the thing was bigger than a refrigerator*, and once in a while a sound effect would cause the whole room to shake. There's some movie sound effects that go into the single digits. I've never seen this in a music track. I *thought* there was some six hertz bass on a Plastikman track called 'Ask Yourself', but it turned out to be a false positive, basically the filter I used to analyze the track wasn't set up right.

* Night of The Living Bassheads - diyAudio

 

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I work in the production industry so I'm a bit familiar with this stuff. I'm mostly a video guy, but audio fascinates me.

At a local(Richmond, Va) soul/rap show this year the local sound company showed up with 24 sub cabinets, each with three 18s with around 50-60kw for the subs. In an open air amphitheater it got pretty loud

I worked the Srillex show when it came through, they brought their own power supply, it was a semi trailer mounted generator. Their power distro was a single frame that was about eight feet long, six feet high and three feet wide. It was so heavy that when they set it on the mobile stage, it broke the deck, they had to put it under the stage. I don't know how much power was running to the sound system, but it did have a wall of subs like in the above picture. The whole setup was LOUD. At about a mile away it was as loud as your average club on a Saturday night.

Their video screen was a pretty slick prototype unit, incredibly easy to repair on the fly and VERY light.

One that stands out for being unique, but not because of how loud it got, is Sarah McLachlan's current tour. I watch a lot of shows on the side wing at that venue and the sound is usually ok in that location. But on this show there was almost no sound at all. The sound reflecting off the restroom in the back of the open air venue was the loudest sound source when not in front of the stage. As you walked towards the seats there was a window of about 3 feet where the volume level increased dramatically. It was a pretty amazing thing to experience.

We couldn't use her video wall because we can't get the height out of that venue. Each column of LED is one piece that rolls up on an axle and they can't simply leave off the bottom sections to make it shorter. Normally a video wall is made up of individual panels that you piece together, then scale the video to fit.
 

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Discussion Starter #50
Yes!

Here's some things that amazed me about these shows:

1) At the Bassnectar show in Vancouver BC, the sound behind the stage was easily 20dB quieter than in front of the stage. The cardioid subs he was using was basically eliminating the reflection off of the back wall. (Okay, 20dB of attenuation isn't' perfect, but it makes a huge difference in tightening up the bass.)

2) At the Skrillex show in BC the concrete walls were flexing. I've never seen that in my life; so much bass it was literally making the walls flex like a balloon.

I have no idea what is up with the Canucks, but YOWZA do they love bass.


P.S. The location in my profile is a goof, I actually live in San Diego and used to live in Seattle and Portland. BC was a two hour trip from my home.
 

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Yes, the cardioid setups are becoming more popular. My local sound company just started playing with them this summer so that they could do it if the customer requested. When I asked one of the guys about it he explained it and seemed a tad surprised that a silly video guy understood :D

With a cardioid setup running it is much more pleasant to spend countless hours backstage babysitting equipment, especially when trying to catch a nap on some empty cases!

I have a picture of a friend napping against 12 of the cabinets at the soul/rap show I mentioned, while 50 Cent was playing! That guy can nap anywhere...

What's most amazing about using sound to make concrete flex, is think about how much the moving speaker parts weigh compared to the concrete!

I just moved to Richmond about 4-5 months ago, I just forgot to update my location. I was born and raised in the Greenwood neighborhood of Seattle and have spent most of my life there. Right now I'm sitting in Alabama, I've got 7 LED walls to start setting up on a golf corse tomorrow, the humidity is gonna kill me!
 

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Also, what you say about experiencing that much bass in an open air venue is spot on. There is no way to compare it to anything else. I've built a car that did 162 on music from the passenger seat, with the doors open, it's a neat experience for sure, but it doesn't compare to loud bass in an open air venue. I think the open air bass wins because you don't have a vibrating car seat, door panels and a thin floorboard distracting you from the sound.
 

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Also, what you say about experiencing that much bass in an open air venue is spot on. There is no way to compare it to anything else. I've built a car that did 162 on music from the passenger seat, with the doors open, it's a neat experience for sure, but it doesn't compare to loud bass in an open air venue. I think the open air bass wins because you don't have a vibrating car seat, door panels and a thin floorboard distracting you from the sound.
Sadly this. Also been in several mid 50's on music cars and every good EDM show I've been to is more impressive. Bassnectar at Spring Awakening last year from literally a football field away (it was in soldier field lol) hurt my ears during a transient peak, playing va va voom. The stupid koo koo clock noise was Loud, bass wasnt' super impressive at that distance, but you could hear it and feel it some, I know by 50 yards away you could begin to feel the grass moving and your chest had some pressure on it.. I also heard them indoors in bloomington a couple years ago and they were moving clothes inside the middle of the venue on the floor, using less than 1/4 their gear apparently.


Despite all this the quality is the main difference. Nothing rattles, nothing vibrates and it's not nearfield so you get a very different sound to it. Especially on the lower stuff.
 

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Discussion Starter #54
I caught Nine Inch Nails a few weeks ago. They had an L'Acoustic line array set up. It's one of these newer array designs, the ones that mimic the Danley Synergy horn. (Basically the midranges and the compression drivers are mounted coaxially, like a Synergy horn.)

During the concert I noticed something I've *never* heard at a show: imaging.

It wasn't pinpoint, this definitely wasn't The Magic Bus, but it's the first time I've heard a big rig like that actually have something approaching stereo seperation. I'm guessing it's due to a couple things:






1) Coaxially mounting the midranges and the tweeters gets us a point source from about 300hz - 20khz
2) Line arrays still suck, but they've come a long way. With good shading we can lower the level of the edges so it doesn't create all of the horrendous comb filtering that's a staple of line arrays.


There was as an odd side effect though: It sounded polite! I think this was due to the absolutely insane number of elements, the entire system was basically loafing. It was a very odd sensation. I almost wish they had a way to crank up the distortion. The sensation was a lot like when I listened to some well known tracks on Jon's Magic Bus. The distortion is insanely low, but it's so low it almost feels like it might need to be added back.

I guess this is one of those things you probably get used to, but I'm not entirely sure I *want* my music to sound that clean. Again, this goes against the whole idea of hifi, but Nine Inch Nails playing at 120dB but sounding clear as an unmuddied lake was a bit odd.

 

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Great post man, makes perfect sense! The stuff I really dig (DJ Magic Mike, Bass Mekanik, Techmaster PEB, Beat Dominator (mekanik's alias early on in 90's), Bass 305, basically all the "oldschool" Miami and Euro bass stuff, seems to be mostly pure sine tones (fundamentals as you just taught me) with not much harmonics. That's something I always loved was lack of harmonics in the bass. If there's a song with sine wave bass sweeps and drops I'm all over it, (must have equally great treble and mids to show off the highs). I'll have to check out these guys I might like them.
My TWO Pandora stations are DJ Magic Mike (for work) and Public Enemy (for truck and home)!
 

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I've worked with the L'Acoustic stuff before, I've never had a problem with their sound. The thing that always impressed me was how light it was compared to your typical touring cabinet. When you are pushing/pulling those things up and down truck ramps you REALLY learn to appreciate the newer, lighter gear these days.



I caught Nine Inch Nails a few weeks ago. They had an L'Acoustic line array set up. It's one of these newer array designs, the ones that mimic the Danley Synergy horn. (Basically the midranges and the compression drivers are mounted coaxially, like a Synergy horn.)

During the concert I noticed something I've *never* heard at a show: imaging.

It wasn't pinpoint, this definitely wasn't The Magic Bus, but it's the first time I've heard a big rig like that actually have something approaching stereo seperation. I'm guessing it's due to a couple things:






1) Coaxially mounting the midranges and the tweeters gets us a point source from about 300hz - 20khz
2) Line arrays still suck, but they've come a long way. With good shading we can lower the level of the edges so it doesn't create all of the horrendous comb filtering that's a staple of line arrays.


There was as an odd side effect though: It sounded polite! I think this was due to the absolutely insane number of elements, the entire system was basically loafing. It was a very odd sensation. I almost wish they had a way to crank up the distortion. The sensation was a lot like when I listened to some well known tracks on Jon's Magic Bus. The distortion is insanely low, but it's so low it almost feels like it might need to be added back.

I guess this is one of those things you probably get used to, but I'm not entirely sure I *want* my music to sound that clean. Again, this goes against the whole idea of hifi, but Nine Inch Nails playing at 120dB but sounding clear as an unmuddied lake was a bit odd.

 

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I don't think the whole rig was ever deployed all at once but if it was,probably a lot of that wattage is marketing.


I regularly work with a rig that's using 12 crown k2 amps bridged at 1600 rms into a pair of horn loaded 15s on each amp. it is..very powerful, also very big and not tour/truckpack friendly. but the sound I get out of this old no compromise cabinet design with updated drivers and power is nothing short of amazing.

I cant find a pic of it for obvious reasons but if you google image search "klipsche mcm1900 burning man" you will see pics of the rig..it doesn't just go to burning man.
 

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Having been to countless drum amd bass shows and half the number of dubstep shows in the last decade, I'd have to say that that the 3 loudest shows were ltj bukem, chase and status(before they went rockish a la pendulum), and caspa and rusko.

Ltj was playing in this area of the LA sports arena that was an intersection for human traffic, sidewalk area, and when he went on, I swear the concrete slabs I was standing on were shifting, bouncing.

Chases and status played on another area, a large balcony of the same sports arena, and had the tightest bass.

Caspa and rusko played in a large warehouse, and by far I had experienced the most spl in one sitting.

Actually, the most spl I had experienced was at a virus records party at the wmc in 2007. My first dubstep party, which had three levels, the upper two being dnb, and the first level beong dubstep. The first level was really tight and small for the equipment that was ised. It was roughly 16000 sqft, with a bar in the middle and subwoofers lined against all the walls. There was so much bass, my internal organs and eyeballs were being rattled. It was definitely a double hearing protection zone(earpligs and earmuffs), but my body literally could not take the deep spl of that first floor I could only take a couple minutes of exposure at a time.

I loved going to dnb shows in the early 2000s, but soon after the headliner, typically the sound would fall off from being pushed way too far.
 
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