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dB Drag Racing
Exedore writes "For a paltry $80,000 outlay, you too can fight back against the punk kids blasting gangsta rap from their Honda Civics. Enter the strange (and rather loud) world of dB Drag Racing and join a small group of dedicated competitors in their quest for the loudest car sound system possible. The numbers: 130,000 watts output, 177dB, 10,000 lbs. of equipment (including the vehicle and all the sound insulation needed to protect those nearby). It might not be quite up to Disaster Area standards, but it's not far off."
yeah but remember dB is logarithmic, 194 is a shitload louder than 150 or whatever they're doing now.
A BIG SHITLOAD!!!
If by "reboot" you mean "destroy" (and I think you do), the magnetron from a microwave will do fine. You will need a microwave horn to aim it, though, or you'll boil your blood.
Go to www.4hv.org, go to the buy and sell thread, and ask someone if they will sell you a HERF unit, and tell them what you need it for.
That's where David Shriner's Klingon zapper comes in. Wait until a traffic light, point and zap, I mean *ZZZZAPP*, and enjoy the silence. Plus, it destroys the electronic ignition of the prick's car, allowing you to drive away without fearing a pursuit. Now if only RadioShack carried them...
I am going to market them to retirees and quiet-loving coders under the brand Rap-B-Gone (TM). Any takers?
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Mad science! Robots! Underwear! Cute girls! Full comic online! http://www.girlgeniusonline.com/
From the article: "every 10 dB increase equivalent to a doubling of perceived sound."
In high school physics, I was taught that an increase of 3dB doubles the intensity/amplitude of the sound. My teacher concluded that +3dB would mean you hear a sound twice as loud. Then he went on to explain that P (power) is directly proportional to 1/d (the inverse of the distance squared).
I know that the Richter scale works on the idea that an earthquake of 6 on the Richter scale is double the strength of one of 5 on the Richter scale.
But have I been mislead? Is "perceived sound" different from amplitude/intensity? Did I really get staight 'A's in pyhsics?
Mike
Tux, myself and my lady regularly engage in 3somes - over the home network.
In fact, that's exactly what many competitors do. They overload the input to the amplifier to produce square waves at the tuned frequency of the enclosure/vehicle.
As for the battery thing, many multiple serial/parallel setups in use, along with external regulators, etc. to keep the voltage level up while banging.
For those who have never seen it, The official dB drag website. Wayne Harris, they guy who started this, used to work for Rockford Fosgate.
Overrated / Underrated : Moderation
The sound control works on a mixture of sheer volume and psychological effects; strictly speaking it's not a directly physical effect.
I really don't care to think of what would happen if a persons resonant frequency was "accidentally" broadcast.
Only in Star Trek does everything have a resonant frequency. "People" do not have resonant frequencies; we are too soft and too squishy. In order to have a resonant frequency there must be some kind of resonance, which arises because the waves (whatever they are) are sharply and cleanly reflected, and can reinforce each other. When they are mushed up, they cease to resonate and you get more normal, mundane effects.
Certain parts of the body, mostly bone, can have a resonant frequency, but everybody's will be different. In fact, if you try, you can probably locate your jawbone's resonant frequency. Every once in a long while (on the order of once every couple of years), something will manage to hit one of my bone's resonant frequencies loud enough to be very unpleasent, generally construction equipment. Even so, my bones didn't crumble for various reasons, including the fact that even bones don't have very good resonant frequencies, and it's embedded in a soft goo.
So you can't simply broadcast some magical noise and watch the crowd dissolve. Of course you could kill them with pure power; an explosion's concussion can do that. But that isn't really "sound" in the traditional sense (no real periodicity, just one burst, maybe two or three significant oscillations (for nuclear-sized blasts), and that's it; the essense of "sound" is the wave nature).
Star Trek really promotes some bad science here; really strong resonance, strong enough to hurt things, is not an every-day, everywhere-you-look phenomenon. Simple observation will confirm this fact; despite the wide variety of noise in the modern world, things conspicuously fail to blow themselves to smithereens because something was hit by its resonant frequency. It's the exception rather then the rule. You need a very regular structure that's also very hard, which doesn't happen much in nature. The reason we see any significant effects at all arises from our tendency to build regular and hard structures, like Tacoma Narrows or your shower (a rectangle box lines with tiles? Show me something like that in nature!).
A similar answer to this message's grandparent: You can pulverize some things with sound, but mostly just hard things. The technology is pretty simple and if it's easy or useful, it's already being used in industry somewhere for something. You don't sound used as a pulverizing weapon because it's useless for that purpose. Generally, if you're trying to pulverize something it's easier to just hit it (not being sarcastic), but I've seen some exceptions (and even that is just "loosening" things with sound, it's sound plus "conventional" pressure and some rotation that all comes together to do the drilling).
She already _is_ tone deaf, isn't she?
What a long, strange trip it's been.
3dB is the limit of relative sensitivity, that is, average person can only hear the difference between two sounds if the difference between their loudness is 3dB.
Nice one buddy.. 112 dB is hardly uber load though.
Isobarik - two woofers basically facing each other, with a very small area of space so the cones do not touch when fully extended. The woofers are out of phase (+ and - connected the opposite) meaning that as woofer 1's cone extends out, woofer 2's cone is moving back), it is basically push-pull. The main function of isobarik configurations is that the optimum enclosure of a sub is halved, so instead of needing say 2 cubic feet per woofer for a good frequency response you now need 1 cubic foot for the both of them, the configuration is around 3dB less efficient than two woofers in a box (or so they say).
The benefit of isobarik configurations is that the frequency response of the box becomes very flat strangely enough.
I have an isobarik configurated box (2 15"s) but i would hardly consider it the reason why it is loud. Nor would I consider 7th order crossovers but he may be talking about a custom enclosure. Very creative people can produce amazing results spl and quality wise from creative boxing.
And anyone who buys a prefab enclosure deserves what they get. When one buys a sub they should design the box to their own requirements. Depending on whether you want punchy or deep bass, loud or flat frequency response etc.. this comes down to enclosure size, shape and porting (or not porting).
*I* can.
I did high end car audio for a living for quite a while, but some of my customers didn't really want high end so much as maximum boom. The customer is always right, eh?
Well, take one boom-lovin' customer with Mom's credit card, add an installer with an engineering background, and you have some serious bass. I recall getting high 120's at 17Hz (yes, seventeen cycles per second, measured by my LinearX LMS system -- poor man's Audio Precision) out of four secondhand Soundstream 8's in a BMW, f'rinstance, and with a good ole acoustic suspension design.
Your vented bandpass boomeroo probably moves some air, but I hope it's not "seventh order" -- that would be a waste of power. The "order" of a box roughly works like this:
- First order: 6dB/octave (or so) highpass at (about) driver Fs, or "infinite baffle".
- Second order: 12dB/octave highpass at enclosre F3, generally acoustic suspension (sealed volume lower than driver's Vas).
- Third/Fourth order: 18-24dB/octave highpass at enclosure F3, generally a standard bass reflex (vented, "ported") enclosure. Slope varies depending on tuning, rule of thumb is 24dB/octave.
- "Fifth Order": Sealed bandpass enclosure with 12dB/ocatve highpass above acoustic suspension chamber's F3 and 18dB/octave lowpass below vented ("front") enclosure's F3. Got its "order" by adding low and high pass characteristics.
- "Sixth order": Either a "fifth order" enclosure with an additional electrical lowpass filter (think "coil") or a vented bandpass design with a 18dB/octave highpass above "rear" chamber F3 and 18dB/octave lowpass below "front" chamber F3.
- "Seventh order": Vented bandpass design with and additional electrical lowpass filter (think "coil" again) or a sealed bandpass enclosure with a 12dB/octave lowpass filter (think "cap and coil" or "active crossover").
- ...
- "Tenth order": Vented bandpass with additional 12dB/octave high and lowpass -- or -- 24dB/octave lowpass filters (think "gang o' caps'n'coils" or "decent active crossover").
The "orders" tell you very little and are pretty arbitrary. Some marketing schlub at Rockford/Kicker/JL Audio overheard one of the R&D guys talking and thought "seventh order" sounded cool cuz seven is, like, a totally rad number and would rule and stuff.Those coils are just heaters unless you only have two amplifier channels, so you really DON'T want a "seventh order" boomerator
Isobaric (yeah, Kicker coined "Isobarik", but I always thought it was dumb) loading allows you to make the box a lot smaller for a given resonance at the cost of 6dB in power efficiency vs. driving the two speakers normally. You're usually better off just using a single speaker one size down from the ones you're thinking of doubling up if you're hurting for space, but sometimes you gotta do what you gotta do. It's also an excellent way for an installer to sell twice as many speakers in a given boomola. The customer isn't getting ripped off, though, because he gets to say "isobari[c/k]"
I'm glad you enjoy your system -- be careful of your hearing, though. Oh -- and don't say "seventh order" again or I will lecture you a second time. Go and sin no more.
Sigh
Thousands of dB?
:) Ofcourse they probably aren't using equipment intended for music playback, but still...
If you need to double the amp power per three dB, that would require an insane amount of energy.(You do the math
I remember reading an article in some hifi magazine wih calculations of the energy and speaker requirements to produce 1000 dB, as far as I remember you'd need an energy source equivalent of more than a few stars the type of our sun. And a speaker membrane moving back and forth a distance equivalent of the size of our solar system.
You can't easily go deaf from loud bass.
Absolutely incorrect. Loud bass is, in fact, a sure-fire way of damaging your hearing. Read this information from an audiologist and come back when you finish.
Most noise-related deafness is from high frequencies.
Again, wrong. Hearing damage usually manifests itself as a degradation in the ability to hear high frequencies. But you are mistaking cause and effect. The hearing loss can be caused by excessive SPLs (sound pressure levels) at any audio, or even subsonic, frequency. If your hearing was damaged by 20hz bass at an excessive volume, the effect would probably be a loss of ability to hear high frequencies, but that does not mean that the high frequencies caused the hearing loss.
Hey all...
:-) )and therefore we are forced to come up with a way around the restriction. To some of us its just as fun as figuring out how many gigahertz we can squeeze out of an overclocked CPU.
I didnt have time to read every response to the entire post, but I thought I would come over to your board and speak a little on the subject.
I agree that there are alot of punk kids out there that mis-represent what DB Drag is all about. And just like "hackers" give avid computer users a bad name - these punk kids or people without respect for others gives the DB Drag world a bad name.
To begin - most truly serious DB Draggers dont drive thier cars around annoying people. Yes - there alot of "us" that cannot drive thier cars around at all... but it pretty much equates to a real drag racing car - those arent street legal either. Alot of our cars are so specialized that it would simply be impossible to safely operate the vehicle in the street.
There is a world of diffrence between a DB Drag Racing competitor and a kid who has seen one too many movies about racing and hasnt developed a sense of respect for others. Myself for instance - I listen to my car system pretty loudly while on highways with the window down... but the second I come off the highway, enter a residential area, or come to a stoplight - not only do I turn it down, alot of the times it goes OFF altogether.
Not many people will ever truly understand other peoples hobbies, and DB Drag racing is no diffrent. To some people it seems a horrible waste of money. To others it seems too easy to prove a challenge. To me it was easy to reach a certain level of performance in competition, but after that you have to start applying more than simple physics or adding more and more speakers to get louder. Eventually you hit a point where you get diminishing returns. There are alot of things that are not legal in competition (the afforementioned pressurized cabins for one
The world of DB Draggers learns alot from reading feedback such as this. It is painful to think of someone defining your hobby as something used to annoy other people. But in reality it is only a small percentage of people that do such things. It makes about as much sense as racism. We all pretty much stick together in our sport, and save the bad apples - we all come out better for it.
Before I take up entirely too much space here on your board (some of you may think that already) ill draw to a close.
P.S. 10 Db IS in fact a "doubling in percieved sound level" to the human ear. When you mentioned 3db being a doubling - it IS... but it is a doubling of apparent signal level. To an electronic meter, a 3 Db gain reads as twice the signal, but is sometimes very hard to pick up with the human ear.
By the way... if you want to see the Good (mixed in with the little bit of inevitable bad... you can find a forum of DB Draggers at http://www.termpro.com
I only ask that you conduct yourselves as civilly as I have here.