posted
I'm looking to know if sound waves travel along surfaces as soon as they come out of the port.Or do they just go everywhere lol?
-------------------- Steven Tyler integra 2006 WF 2nd place 129.9 bassrace JVC Arsenal KD-AHD39 HD Radio/CD Receiver Alpine type-X comps Havn't picked out the amps or subs yet. All on the way soon to be installed
posted
what do you mean follow surfaces? It's a case by case scenario.
Say, for example, you take a horn (mid/high) and build the dash around it...basically by molding the dash having it flow with the shape of the horn, enlarging the mouth...it will esentially 'tune' it lower.
Same goes for flared ports. The shape/radius will alter the frequency.
So yes, the sound waves can travel along surfaces. But it also reflects.
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quote:it would all be for nothing without my favorite cawk-smoker NAvi
posted
cutting a slit in pvc longways and putting it on the edges of the ends of the ports like some people do with walls and such in spl. does this lower the tuning so they can make the port really short?
-------------------- Steven Tyler integra 2006 WF 2nd place 129.9 bassrace JVC Arsenal KD-AHD39 HD Radio/CD Receiver Alpine type-X comps Havn't picked out the amps or subs yet. All on the way soon to be installed
posted
it's a case by case scenario. Can't say it will lower the tuning...or raise it for that matter.
Take into consideration: Say someone has a wall with a 24" wide port. Then use 6" pvc around the edges of the port mouth. That's going to take up to a good 3" along each edge right? So the port is no longer 24" wide...
changing the size (changing the shape is essentially changing the size) will alter the freq.
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quote:it would all be for nothing without my favorite cawk-smoker NAvi
-------------------- WWW.DCSOUNDLAB.COM Team Hifonics Voted 2004 DB Drag Rookie of the year 2004 World Finals 3rd place finish SS1-2NW 2005 World Finals 4th place finish SS1-2NW 2006 World Finals 3rd place finish SS3-4 2006 Super Street DeathMatch Participant 2007 Super Street 3-4 163.1 with 2 amps 2007 West Coast SS3-4 Champion Posts: 2747 | From: West Coast | Registered: Nov 2003
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posted
Someone mentioned the flare of a horn, but the flare of a horn is not tuning it lower, the horn itself deals with resonance, it has a small section, high resonant point all the way to whatever size you finish with at a lower resonant frequency, it is essentially the same thing as the BOX is for an acoustic suspension, but it has multiple FS points, leaving a bandwidth of FS if you will, within that bandwidth, it is highly efficient. The shape of the horn simply directs it's radiation path. The sound waves reflect, they won't just skim along the wall, air will however. As long as you remember to separate the two and what each does for SPL if that is your end goal. Case in point: our van has the "rounded vent lip". Let's just say that the vent is large to say the least. What most people would consider the length of the vent, determined by whatever board comes from the face into the box is not very deep, but allows a very big radius to round it off. At first, it was flat with maybe a 1" radiused edge, playing it's loudest at so and so frequency. Once further radiused with X amount of a radius, the frequency did not alter, but the output went up drastically. "Drastically" was determined from the idea that the beginning SPL # was already above 162dB.....to make a change as large as we gained is drastic since vehicles of this magnitude do not gain 3dB from doubling power or cone surface area. As far as Aero ports go, they also have a very high resonant frequency as compared to wood vents, this does create multiple frequencies being emmited from the vent, so the length of it can tune the enclosure, but the size of the flare can also help with velocity and turbulence as well as lend a second frequency, which can assist at the dash. But simply put, if you study acoustics a little, you'll see that soundwaves do not "follow or skim along" a surface, rather they reflect off of them. Air will, with turbulence ofcoarse.
-------------------- HO Audio Team Leader 14 Combined world titles Countless world records broken And just to step out on a limb Some left to break!! Posts: 176 | From: edmond | Registered: Jun 2001
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