vasubandu Posted February 12, 2018 Author Share Posted February 12, 2018 58 minutes ago, CECAA850 said: That's not how subwoofer design works. You take the driver(s) load the TS parameters into a modeling program, figure out what tune you want, check port velocities and driver excursion THEN see what type enclosure is recommended by the program. At that point you'll have some sort of educated guess as to the enclosure size. I get that, I really do. But the math guy in me says that the process you describe must work equally forwards or backwards. Once i have the enclosure design and driver parameters, I can run simulations with different port and other variables to see what would occur. I can change the variables until I get numbers I like, and then I can finish the enclosure t the design. I agree that I could not make port decisions before doing the calculations, but there is no reason I could not start with the overall enclosure shape and dimensions. I am aware that my enclosure may be too big. IN that case, I will use calibrated bags of sand to reduce the air volume. The thing is I don't want t build a subwoofer or even a great subwoofer. I want to build a giant tube subwoofer. I laugh too when I read that. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 27 minutes ago, vasubandu said: What would happen if I pulled the drivers a foot or two into the tube? Or changed their direction? That can all be simulated. If you reverse a driver and reverse the polarity on that driver there will be no difference. Quote Link to comment Share on other sites More sharing options...
Ceptorman Posted February 12, 2018 Share Posted February 12, 2018 I hope your experiment works out, pretty gutsy to even try it. Carl (Cecca) does know a lot about subs, I believe he has built quite a few. The only thing I might add, you might take some measurements and make sure you can move it. Most doors are 36" wide at the most, and that depends on removing the door itself, and maybe even the hinges. It would be a bummer to make this thing in your garage, then have it too big or heavy to move it. Good luck, keep us informed. Pics are always nice. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 23 minutes ago, vasubandu said: I can change the variables until I get numbers I like To a point. Normally if you have a fixed or semi fixed enclosure size, you need to find a driver that will work properly with that size enclosure in mind. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 26 minutes ago, vasubandu said: But the math guy in me says that the process you describe must work equally forwards or backwards This is like saying, I have a car. I know how fast I want it to accelerate, I know how many cubic inches the engine will be and I know how much I want it to weigh. If one of those parameters is way out of whack your project will be a colossal failure. Of course a nice paint job may be more important than the actual performance of the vehicle itself to you in which case you would ultimately be happy which is really what's important in the end. I see you putting the emphasis of this project on aesthetics and performance is secondary to you. If that's the case, I wish you luck. Please post pictures as I'm sure it will be a fun project to watch come together. Quote Link to comment Share on other sites More sharing options...
vasubandu Posted February 12, 2018 Author Share Posted February 12, 2018 10 minutes ago, Ceptorman said: I hope your experiment works out, pretty gutsy to even try it. Carl (Cecca) does know a lot about subs, I believe he has built quite a few. The only thing I might add, you might take some measurements and make sure you can move it. Most doors are 36" wide at the most, and that depends on removing the door itself, and maybe even the hinges. It would be a bummer to make this thing in your garage, then have it too big or heavy to move it. Good luck, keep us informed. Pics are always nice. I can vouch for @CECAA850's knowledge. The thing is, he sometimes seems not to realize it himself as he casually throws out huge chunks of information. My project is much different because of his advice even if he still thinks I am out to lunch. My basement room has a 36 inch wide door t the outside that will actually allow a 36 inch object to pass through it. And I will make it in the family room with the TV. It is my space. I am planning to pick up the shell pieces tomorrow and will assemble them and post pics. You guys need your laughs. Quote Link to comment Share on other sites More sharing options...
vasubandu Posted February 12, 2018 Author Share Posted February 12, 2018 15 minutes ago, CECAA850 said: That can all be simulated. If you reverse a driver and reverse the polarity on that driver there will be no difference. I know it can be simulated, and maybe those simulations are all accurate, but it would still be fun to see it. And every now and then, the simulations turn out to be wrong. Quote Link to comment Share on other sites More sharing options...
vasubandu Posted February 12, 2018 Author Share Posted February 12, 2018 14 minutes ago, CECAA850 said: To a point. Normally if you have a fixed or semi fixed enclosure size, you need to find a driver that will work properly with that size enclosure in mind. OK now you have me concerned. I have an enclosure that is an empty tube 6 feet long and 36 inches wide. I have the space recommended for the driver. Is there some reason why the driver would still now work in that enclosure? I thought that as long as I had nothing but wide open spaces and met space requirements, I was OK. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 2 minutes ago, vasubandu said: OK now you have me concerned. I have an enclosure that is an empty tube 6 feet long and 36 inches wide. I have the space recommended for the driver. Is there some reason why the driver would still now work in that enclosure? I thought that as long as I had nothing but wide open spaces and met space requirements, I was OK. Ported? Sealed? What did everything look like once you plugged it into winisd and the sonotube calculator? Be sure you plug in the inside dimensions when you calculate, not the outside dimensions of your enclosure. If ported, subtract the volume of your port and driver when figuring total interior volume. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 If the picture in your first post is what you're building, I'll assume it's a dual sealed enclosure? If so, calculate the cubic area of the cylinder then subtract the volume of the driver displacement. That will give you total enclosure volume. If you divide that by 2 and the driver specs say it will work with that volume then you're good to go. Quote Link to comment Share on other sites More sharing options...
vasubandu Posted February 12, 2018 Author Share Posted February 12, 2018 9 minutes ago, CECAA850 said: This is like saying, I have a car. I know how fast I want it to accelerate, I know how many cubic inches the engine will be and I know how much I want it to weigh. If one of those parameters is way out of whack your project will be a colossal failure. Of course a nice paint job may be more important than the actual performance of the vehicle itself to you in which case you would ultimately be happy which is really what's important in the end. I see you putting the emphasis of this project on aesthetics and performance is secondary to you. If that's the case, I wish you luck. Please post pictures as I'm sure it will be a fun project to watch come together. I understand why you would think that, but in the end this is all about performance. Or rather it is about the effect of volume on performance. If I am right that the industry is squeezing enclosure size to the detriment of performance, then providing optimal space should improve performance. If it doesn't then my premise is wrong. I personally could not care less how it looks, but if I want to get others to look at it, I might need some aesthetic or curiosity help.\ Let me ask you this. In your system, which is pushed harder, speakers or subwoofer? Which is run closer to its capacity, and which, if any, is every driven beyond capacity? Which is more likely to be damaged from use? I don't know the answer to these questions of course, and they are genuine questions. You know what I hate about subwoofers? It is that subwoofer sound that they all make. Hard to describe, but I know it when I hear it. It does not sound like any natural sound that I have heard, but it is part of subwoofer language. Usually right at the beginning. It is noise, not sound. I wold love to get rid of that and have nothing but sound from my subwoofer. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 1 minute ago, vasubandu said: Let me ask you this. In your system, which is pushed harder, speakers or subwoofer? Neither is pushed anywhere near their limits. I believe in headroom and overkill to keep everything clean. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 2 minutes ago, vasubandu said: It is noise, not sound. You're listening to either: A crappy sub, a sub being pushed beyond it's capability or more than likely a sub that has not been set up properly. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 18 minutes ago, CECAA850 said: If the picture in your first post is what you're building, I'll assume it's a dual sealed enclosure? If so, calculate the cubic area of the cylinder then subtract the volume of the driver displacement. That will give you total enclosure volume. If you divide that by 2 and the driver specs say it will work with that volume then you're good to go. OK, 2 drivers need between 16 and 24 cubic ft in a sealed enclosure. I wouldn't go more or less than that. Each driver displaces .75 cu ft. Go ahead and do the math. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 12, 2018 Share Posted February 12, 2018 Unless I forgot to carry the one it looks like that tube will be almost twice as large as it needs to be. Please check my math. Too large of an enclosure can damage the drivers as they don't have the proper air spring to keep the drivers from overexcursion. That size would probably work as a ported enclosure although I don't think I've ever seen a ported dual driver tube. Quote Link to comment Share on other sites More sharing options...
vasubandu Posted February 12, 2018 Author Share Posted February 12, 2018 43 minutes ago, CECAA850 said: If the picture in your first post is what you're building, I'll assume it's a dual sealed enclosure? If so, calculate the cubic area of the cylinder then subtract the volume of the driver displacement. That will give you total enclosure volume. If you divide that by 2 and the driver specs say it will work with that volume then you're good to go. No, it is ported. I did not include ports because to be honest I was not sure where to put them or how large to make them. I was sure that I can find that information, but it wil be a learning experience. If this was going to be sealed, it would be half the size. The HS-24 is 8-12 cf sealed and 16-20 cf ported. I hope you know that part of the goal here is to give you guys something laugh your asses off about. Won't bother me in the least. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted February 12, 2018 Share Posted February 12, 2018 CECAA850 You have been saying all the right things. Unfortunately they have been falling on deaf ears. I also believe that design comes before buying parts. The problem is that a considerable amount of money is being thrown at the project. In my book, 1) getting a good low end response does not need to be expensive, and 2) two (decent) subs are better that one and that three are even better. All of this is being ignored. What is perplexing is that there a number of good simulation programs that can answer these "what if" questions without spending a dollar. Are they perfectly accurate? Nothing is perfect but that can narrow things down quite a bit. 1 Quote Link to comment Share on other sites More sharing options...
TasDom Posted February 12, 2018 Share Posted February 12, 2018 1 minute ago, vasubandu said: I hope you know that part of the goal here is to give you guys something laugh your asses off about. Won't bother me in the least. 15 minutes ago, vasubandu said: I was sure that I can find that information, but it wil be a learning experience. 2 1 Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted February 12, 2018 Share Posted February 12, 2018 I guess I take this hobby more seriously than others. Secondly, I am a cheap son of a gun and I hate to see others throw money away. Perhaps these are personal flaws ...... Quote Link to comment Share on other sites More sharing options...
jason str Posted February 13, 2018 Share Posted February 13, 2018 9 minutes ago, PrestonTom said: CECAA850 You have been saying all the right things. Unfortunately they have been falling on deaf ears. I also believe that design comes before buying parts. The problem is that a considerable amount of money is being thrown at the project. In my book, 1) getting a good low end response does not need to be expensive, and 2) two (decent) subs are better that one and that three are even better. All of this is being ignored. What is perplexing is that there a number of good simulation programs that can answer these "what if" questions without spending a dollar. Are they perfectly accurate? Nothing is perfect but that can narrow things down quite a bit. Many need to learn the hard way or just not learn at all. Just my perspective. 1 Quote Link to comment Share on other sites More sharing options...
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