MrBigs63' Posted June 12, 2014 Report Share Posted June 12, 2014 i'd try to get that PV in the 20s Why? It is one of those things where you do not want too much pv because it will cause a whistling or chuffing sound from the port, but if it is too little you will loose a lot of air flow and reduce spl I believe. Someone please correct me if I am wrong. I try to keep my port velocity at the least between 35-45 ft/s. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted June 12, 2014 Report Share Posted June 12, 2014 It is one of those things where you do not want too much pv because it will cause a whistling or chuffing sound from the port, but if it is too little you will loose a lot of air flow and reduce spl I believe. Someone please correct me if I am wrong. I try to keep my port velocity at the least between 35-45 ft/s. I'm a big believer in keeping port velocities low to eliminate port noise & compression, that's why I'm curious about why someone would want it to be higher. I do not claim to be any kind of SPL expert, but I find it very hard to believe that higher port velocities do anything to improve SPL. I've someone has any data to prove otherwise I'd be very interested to see it. When I saw your 35-45 number I was thinking in meters/sec and I was like "wow, that high" but then I saw it was in feet so actually your number is pretty modest. "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...
Joe X Posted June 12, 2014 Report Share Posted June 12, 2014 Hi guys, I'm trying to learn BassBox Pro and am trying to design a box for my HDS312. Is this a good response curve or is it too peaky? You need to factor in a cabin gain transfer function (which need to be measured) to reduce at least error, real world expect the response to be much peakier than you see. Link to comment Share on other sites More sharing options...
MrBigs63' Posted June 12, 2014 Report Share Posted June 12, 2014 It is one of those things where you do not want too much pv because it will cause a whistling or chuffing sound from the port, but if it is too little you will loose a lot of air flow and reduce spl I believe. Someone please correct me if I am wrong. I try to keep my port velocity at the least between 35-45 ft/s. I'm a big believer in keeping port velocities low to eliminate port noise & compression, that's why I'm curious about why someone would want it to be higher. I do not claim to be any kind of SPL expert, but I find it very hard to believe that higher port velocities do anything to improve SPL. I've someone has any data to prove otherwise I'd be very interested to see it. When I saw your 35-45 number I was thinking in meters/sec and I was like "wow, that high" but then I saw it was in feet so actually your number is pretty modest. I am in no way a box building/designing expert, I was just told to always keep port velocity up around 40 ft/sec by few people on the forum here. I have never built a box with port noise, and some of mine have gotten up closer to 60-65 ft/s. Then again I have built a box with around 18ft/s I believe it was, and it sounded awful, and it had no balls during any low end. Might have just been that box though... Link to comment Share on other sites More sharing options...
timc31610 Posted June 13, 2014 Author Report Share Posted June 13, 2014 Joe, how is that measured? Is there an easy way or should I shoot for the flattest response? My Build Log 94 Civic http://www.stevemeadedesigns.com/board/topic/188644-94-civic-4-door-build-loq-suggestions-wanted-will-be-super-slow-mo/ Faceebook reluctantly Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted June 13, 2014 Report Share Posted June 13, 2014 Joe, how is that measured? Is there an easy way or should I shoot for the flattest response? If you take your box specs from BBP and put them into WinISD I can tell you how to roughly approximate cabin gain. "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...
timc31610 Posted June 13, 2014 Author Report Share Posted June 13, 2014 Joe, how is that measured? Is there an easy way or should I shoot for the flattest response? If you take your box specs from BBP and put them into WinISD I can tell you how to roughly approximate cabin gain. Triticum, I have tried winisd and can't even get my driver loaded. I get an error saying missing parameters. My Build Log 94 Civic http://www.stevemeadedesigns.com/board/topic/188644-94-civic-4-door-build-loq-suggestions-wanted-will-be-super-slow-mo/ Faceebook reluctantly Link to comment Share on other sites More sharing options...
Krakin Posted June 13, 2014 Report Share Posted June 13, 2014 If WinISD has calculated any parameters from previous parameters entered, then do not change the calculated ones as you will get that error. 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...
mothra Posted June 13, 2014 Report Share Posted June 13, 2014 It is one of those things where you do not want too much pv because it will cause a whistling or chuffing sound from the port, but if it is too little you will loose a lot of air flow and reduce spl I believe. Someone please correct me if I am wrong. I try to keep my port velocity at the least between 35-45 ft/s.I'm a big believer in keeping port velocities low to eliminate port noise & compression, that's why I'm curious about why someone would want it to be higher.I do not claim to be any kind of SPL expert, but I find it very hard to believe that higher port velocities do anything to improve SPL. I've someone has any data to prove otherwise I'd be very interested to see it. When I saw your 35-45 number I was thinking in meters/sec and I was like "wow, that high" but then I saw it was in feet so actually your number is pretty modest. Just over the years I have always had good results keeping port velocity in the 20s. Yes PV in the 30s can and will cause port noise but I find that having a PV below the 20 have issues with overall output at all frequencies. Too low of a PV usually leaves the listener wanting more or with a very boomy sound which I feel is worse than port noise. To increase velocity just decrease the amount of port area. if nothing changes, nothing changes You don't know what you don't know, till you don't know Link to comment Share on other sites More sharing options...
MrBigs63' Posted June 13, 2014 Report Share Posted June 13, 2014 It is one of those things where you do not want too much pv because it will cause a whistling or chuffing sound from the port, but if it is too little you will loose a lot of air flow and reduce spl I believe. Someone please correct me if I am wrong. I try to keep my port velocity at the least between 35-45 ft/s.I'm a big believer in keeping port velocities low to eliminate port noise & compression, that's why I'm curious about why someone would want it to be higher.I do not claim to be any kind of SPL expert, but I find it very hard to believe that higher port velocities do anything to improve SPL. I've someone has any data to prove otherwise I'd be very interested to see it. When I saw your 35-45 number I was thinking in meters/sec and I was like "wow, that high" but then I saw it was in feet so actually your number is pretty modest. Just over the years I have always had good results keeping port velocity in the 20s. Yes PV in the 30s can and will cause port noise but I find that having a PV below the 20 have issues with overall output at all frequencies. Too low of a PV usually leaves the listener wanting more or with a very boomy sound which I feel is worse than port noise. To increase velocity just decrease the amount of port area. I understand how to increase and decrease it. By 20 you mean 20 m/s right? Link to comment Share on other sites More sharing options...
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