revoracing247 Posted November 14, 2013 Report Share Posted November 14, 2013 i don't have any insightful suggestions on what to try next. but i had fun reading it! and i think people should do more experiments (including me lol) and post up results here. it's fun seeing simple things actually proven in real life I think you have a bit of truck stuck in your mud bro ~Ford Ranger, ext cabKenwood DDX4701/0ga stinger wiring for big 31/0ga ofc flextech wiring 3 kinetik 800's AQ2200 @1ohm Sundown Audio X15 in a 27Hz tuned ported box LE BUILD LOG!!! Link to comment Share on other sites More sharing options...
agf144 Posted November 14, 2013 Report Share Posted November 14, 2013 Do since the flared port moves sir with a higher velocity does that add to the sound pressure level or does the split stay the same. I am also interested in dimpled vs non dimpled Chick took 3 shots of Jager, and then, pissed in my mouth.. oh.. wait.. naw.. that wasnt weird.. He probably tearin dat ass up every night. Reason for "insomnia" Ain't sleeping cause he's like a horny hamster on coke. 2000 grand prix gtp: SOLD My Home Theater Build (working progress) 2002 accord coupe subs: 2 soundqubed hds300 12s 4'1" towers tuned to 29hz sub: AQ hdc3 12 Amp: pioneer gm9061 amp: poineer gm9601 headunit: kenwood kdc 255u mids: SQ pro mids midbass: polk db 8s highs: stock mids/highs: shitty off brand Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted November 14, 2013 Author Report Share Posted November 14, 2013 Interesting.Another question is how much of a flare do you need to stop port noise. I know you did a 3/4 round over but would a bigger flare improve it more?Also this testing can help determine if a flared square port will or will not be as effective a flared round port.I've seen a lot of people saying round Ports.with flares are more efficient then square Ports so they need less port area. I chose the 3/4" round over because I heard for round ports and round over one quarter the diameter of your port was the way to so. So 3" port, 3/4" round over. To get the same amount of increase in area with a slot port the outside radius of the flare should be 5/8ths the width of the port. Unfortunetly I couldn't do that because I don't have a 15/16" round over, 3/4" was as good as I could do. I'm sure a larger flare would be more effective, at least to a point. I'd be curious to know what that point is. I've heard that round ports are a more efficient use of port space as well, and I can see why, obviously the inside corners of a slot port are going to have more resistance than the nice smooth circumference of a round port. Not much you can really do about it though, and I think it would only take a slightly larger slot port to make up for the difference. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted November 14, 2013 Author Report Share Posted November 14, 2013 Do since the flared port moves sir with a higher velocity does that add to the sound pressure level or does the split stay the same. I am also interested in dimpled vs non dimpled Someone please correct me if I'm wrong, but I'm pretty sure higher sound pressure is going to come from a higher volume of moving air, not higher air velocity. I think using a smaller port to get higher air velocities is going to hurt your output, not help it. As far as the dimpled thing goes, I understand the reasoning behind it, but I think its a really complicated solution to a fairly simple problem. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
agf144 Posted November 14, 2013 Report Share Posted November 14, 2013 Do since the flared port moves sir with a higher velocity does that add to the sound pressure level or does the split stay the same. I am also interested in dimpled vs non dimpledSomeone please correct me if I'm wrong, but I'm pretty sure higher sound pressure is going to come from a higher volume of moving air, not higher air velocity. I think using a smaller port to get higher air velocities is going to hurt your output, not help it. As far as the dimpled thing goes, I understand the reasoning behind it, but I think its a really complicated solution to a fairly simple problem. Thanks for cleaning that up for me Chick took 3 shots of Jager, and then, pissed in my mouth.. oh.. wait.. naw.. that wasnt weird.. He probably tearin dat ass up every night. Reason for "insomnia" Ain't sleeping cause he's like a horny hamster on coke. 2000 grand prix gtp: SOLD My Home Theater Build (working progress) 2002 accord coupe subs: 2 soundqubed hds300 12s 4'1" towers tuned to 29hz sub: AQ hdc3 12 Amp: pioneer gm9061 amp: poineer gm9601 headunit: kenwood kdc 255u mids: SQ pro mids midbass: polk db 8s highs: stock mids/highs: shitty off brand Link to comment Share on other sites More sharing options...
Souldrop Posted November 14, 2013 Report Share Posted November 14, 2013 Yeah a smaller port would "choke" the volume of air coming out of the port. As far as Port velocity. I figured a rough estimate of sub velocity by using Y=A*sin(wt)where Y is the position of the cone as function of time and if you take the derivative you end up with the velocity which v=A*w* cos(wt) where A is the amplitude or one way xmax and w=frequency*2pi. The equation for velocity can reduce to v= A*w = A*2pi*(freq) since the highest velocity will be at the 0 point. I'm sure this is definitely a ball park estimate, but may be useful for something. 1997 Lexus ES300 HU - Pioneer MVH 7350 Processor - Helix DSP Front Stage - JBL P660C Mid/high amp - Alpine PDX-F4 Subs - 1 IA Death Penalty 12 Sub Amp - Cactus Sounds PF300.1 Link to comment Share on other sites More sharing options...
dfoland93 Posted November 14, 2013 Report Share Posted November 14, 2013 Very cool write up! The spot with least resistance LOL. I would ground to a rubber dildo if it had less resistance than a run of 4/0 wiring. how many poeple work there 3 or 4 lol At crescendo HQ? probably 2-3 At the sweatshop in china? 30,000 children No Engine Link to comment Share on other sites More sharing options...
Joe X Posted November 14, 2013 Report Share Posted November 14, 2013 A hot wire anemometer has been used to measure airspeed in ports, however I believe most of the research on this topic has already been done before. Much of this research have been presented and maybe available from aes.org. Link to comment Share on other sites More sharing options...
dfoland93 Posted November 14, 2013 Report Share Posted November 14, 2013 A hot wire anemometer has been used to measure airspeed in ports, however I believe most of the research on this topic has already been done before. Much of this research have been presented and maybe available from aes.org. I think we all know how lazy people are so this helps keep people updated (i know im lazy) ahha The spot with least resistance LOL. I would ground to a rubber dildo if it had less resistance than a run of 4/0 wiring. how many poeple work there 3 or 4 lol At crescendo HQ? probably 2-3 At the sweatshop in china? 30,000 children No Engine Link to comment Share on other sites More sharing options...
Krakin Posted November 14, 2013 Report Share Posted November 14, 2013 It would be great to see a test doing core limits of the vent and compression and different flare radii. Would also love to see testing at 30hz and 25hz, possibly 20hz but that would be very rare in a real world situation to be played. Krakin's Home Dipole Project http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370 Krakin, are you some sort of mad scientist? I would have replied earlier, but I was measuring the output of my amp with a yardstick . . . What you hear is not the air pressure variation in itself but what has drawn your attention in the two streams of superimposed air pressure variations at your eardrums An acoustic event has dimensions of Time, Tone, Loudness and Space Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears, thus no formula can achieve a definite effect for every listener. Link to comment Share on other sites More sharing options...
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