757lmj Posted April 26, 2015 Author Report Share Posted April 26, 2015 Yes a 1:1 ratio will be less loud around tuning, you can set the ported chamber size so that you have some 3-4 dB bump there, more than that it may start to affect musicality too much, as far as tuning goes, you may want to try a removable port so that you can experiment. How would I do that? I'm leaning towards 4.5 sealed and 9 ported at 47-48hz. What would that give me range wise do u think?? I don't need to play over 52 hz really. And I'd like authority at 28 and 30 hz Link to comment Share on other sites More sharing options...
757lmj Posted April 26, 2015 Author Report Share Posted April 26, 2015 Being told ratios don't matter then being told the larger the ratio the louder doesn't make sense. I want as loud as possible from 30-50hz Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted April 27, 2015 Report Share Posted April 27, 2015 Being told ratios don't matter then being told the larger the ratio the louder doesn't make sense. I want as loud as possible from 30-50hz I never said ratios don't matter, I said that just picking a ratio because you read it somewhere is not what you want to do. You need to understand what effect the ratio has so you can make an informed decision. Yes making the box have equal sized chambers will make it less efficient like JoeX said, but it will get you the bandwidth you wanted. There is no free lunch when it comes to box design. If you want more output from a band pass box you are going to give up bandwidth, plain and simple. Please understand, I'm not saying high aspect ratio band pass boxes are bad. They have their advantages and disadvantages just like anything else. What I'm saying is picking an aspect ratio w/o knowing what it does, or just becase someelse used it is what's bad. My question for you is where did you come up with 4.5 cubes sealed and 9 cubes ported at 47 hz? Do you have good reasons for thinking those numbers will work well for you and do what you want to do? What do you think the box will sound like with those numbers? "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...
757lmj Posted April 27, 2015 Author Report Share Posted April 27, 2015 Being told ratios don't matter then being told the larger the ratio the louder doesn't make sense. I want as loud as possible from 30-50hzI never said ratios don't matter, I said that just picking a ratio because you read it somewhere is not what you want to do. You need to understand what effect the ratio has so you can make an informed decision. Yes making the box have equal sized chambers will make it less efficient like JoeX said, but it will get you the bandwidth you wanted. There is no free lunch when it comes to box design. If you want more output from a band pass box you are going to give up bandwidth, plain and simple.Please understand, I'm not saying high aspect ratio band pass boxes are bad. They have their advantages and disadvantages just like anything else. What I'm saying is picking an aspect ratio w/o knowing what it does, or just becase someelse used it is what's bad. My question for you is where did you come up with 4.5 cubes sealed and 9 cubes ported at 47 hz? Do you have good reasons for thinking those numbers will work well for you and do what you want to do? What do you think the box will sound like with those numbers? Well I've never designed a 4th order. Recommended sealed is 1.25ft^3 I figured gve a bit more for the lows. But not too much because sealed they play 32 Just fine. Doubled the ported chamber size bc what I've read up on says 1:1 will play everythingand 1:3 will be more peaky. I want everything from my system like u just said so 1:2 may be a happy medium? 47hz because I don't need over 52 really. White girls decaf note is about the highest I want. 50-52hz I forget. And I feel like I could get more out of these subs on the low end so I'm trying to cut off the highs I don't need and turn that into better lows.I would think it would play well up to about 50 Hz or so and play the lows a bit louder because of the increase sealed volume. Is this correct? I have no clue what hz would be loudest tho if it would be 47 or close to that only.. or if it would be 47 or so and something lowe also like 32 or 33 maybe Link to comment Share on other sites More sharing options...
757lmj Posted April 27, 2015 Author Report Share Posted April 27, 2015 Hopefully this helps a good bit more Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted April 27, 2015 Report Share Posted April 27, 2015 Yeah that does help. I think I understand what you are looking to do. What you read was correct. 1:3 sealed to ported ratio band pass boxes are going to be quite peaky. IMHO pretty much anything over a 1:1 ratio is peaky, but I have a low tolerance for peakyness and much prefer smooth, even bass. In fact every bandpass box I've built has a larger sealed chamber and a smaller ported one. My concern is that the box you will end up with could be so peaky that it doesn't have good low end output and you will not be happy with it. Let me show you what I mean, and you can come to your own conclusions. Here is a graph showing your current ported box and three different band pass boxes. In this graph I approximated cabin gain, its only an approximation so the actual frequency response you get in your vehicle may be a bit different. However the differences in output between the different boxes should be pretty accurate. The light blue line is your current ported box. To be honest, those subs are kinda funky in ported boxes (not in good way) and its no surprise you are not happy with the low end output. The yellow line is your proposed band pass box with 4.5 cubes sealed and 9 cubes ported at 47 Hz. The red line is the same thing but with 13.5 cubes ported (for a 1:3 ratio). The green line is my suggestion of 5 cubes sealed and 5 cubes ported at 50 hz. You can see that as you make the ported section larger, it does increase efficiency, but only around tuning. Once you get to about 33 Hz and below, all three are the same. The same applies for content above about 58 Hz. Your proposed box has a pretty decent hump around 43 Hz, while that is lower than your ported box, I'm not sure its going to be low enough to make you happy. You could tune the ported section lower, but then you are REALLY going to give up output on the upper end, and you might not like that any either. Hopefully the graph helps you understand whats going on. IMHO the best thing to do, if you really want good low end output, is to sell your subs and get a pair of decent 15"s and put them in a properly designed box. They will only take up about half the space of the band pass boxes you are considering and will do better on the 30-40 Hz content than your current subs in a band pass box ever will. May not be what you want to hear, but that's what I would do. "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 April 27, 2015 Report Share Posted April 27, 2015 If you are going the 4th BP way I would build the 2:1 as you planned and then you can reduce the volume of the ported chamber if you found 2:1 is too peaky, that along with a removable port is a flexible enough setup. Link to comment Share on other sites More sharing options...
757lmj Posted April 27, 2015 Author Report Share Posted April 27, 2015 Yeah that does help. I think I understand what you are looking to do. What you read was correct. 1:3 sealed to ported ratio band pass boxes are going to be quite peaky. IMHO pretty much anything over a 1:1 ratio is peaky, but I have a low tolerance for peakyness and much prefer smooth, even bass. In fact every bandpass box I've built has a larger sealed chamber and a smaller ported one. My concern is that the box you will end up with could be so peaky that it doesn't have good low end output and you will not be happy with it. Let me show you what I mean, and you can come to your own conclusions. Here is a graph showing your current ported box and three different band pass boxes. In this graph I approximated cabin gain, its only an approximation so the actual frequency response you get in your vehicle may be a bit different. However the differences in output between the different boxes should be pretty accurate. The light blue line is your current ported box. To be honest, those subs are kinda funky in ported boxes (not in good way) and its no surprise you are not happy with the low end output. The yellow line is your proposed band pass box with 4.5 cubes sealed and 9 cubes ported at 47 Hz. The red line is the same thing but with 13.5 cubes ported (for a 1:3 ratio). The green line is my suggestion of 5 cubes sealed and 5 cubes ported at 50 hz. You can see that as you make the ported section larger, it does increase efficiency, but only around tuning. Once you get to about 33 Hz and below, all three are the same. The same applies for content above about 58 Hz. Your proposed box has a pretty decent hump around 43 Hz, while that is lower than your ported box, I'm not sure its going to be low enough to make you happy. You could tune the ported section lower, but then you are REALLY going to give up output on the upper end, and you might not like that any either. Hopefully the graph helps you understand whats going on. IMHO the best thing to do, if you really want good low end output, is to sell your subs and get a pair of decent 15"s and put them in a properly designed box. They will only take up about half the space of the band pass boxes you are considering and will do better on the 30-40 Hz content than your current subs in a band pass box ever will. May not be what you want to hear, but that's what I would do. wow thank u very much. Makes much more sense on the graph except I could never load my subs to winisd. Also wasn't aware of these things low end when I got em. I was a bit younger haha. I'm planning on getting 4 15s soon. Simply because of the lower notes and much more cone area per sub. I do see what u mean by the 1:1 very flat. It's more impressive then I thought it would be. Definitely going with either ur 1:1 or my 1:2. The 3 seems way more peaky then I want. And for these subs I want to push em as much as I can so the 1:2 may get me some more of the noise I want. Not too peaky and still has the lows. 1:1 is enticing but I think I want the noise for this setup over the flattest response. It doesn't seem like it will be that much different just looks like the 43 45hz area is louder. Also, what would a 5 sealed box and 7 or 9 ported do? That might meet in the middle of gaining lows and losing highs Link to comment Share on other sites More sharing options...
757lmj Posted April 27, 2015 Author Report Share Posted April 27, 2015 If you are going the 4th BP way I would build the 2:1 as you planned and then you can reduce the volume of the ported chamber if you found 2:1 is too peaky, that along with a removable port is a flexible enough setup.good stuff. Prolly what I'm guna do. Now finding port area for this, how many in^2 of port do u guys recommend for each ft^3 I designed my 9ft^3 side to have a 12 by 12 port thats 9 inches deep. Yay or nay?? That's about 16 inches for each cubic foot Link to comment Share on other sites More sharing options...
757lmj Posted April 27, 2015 Author Report Share Posted April 27, 2015 So 5 sealed and 9 ported seems good. 8 ported there's hardly any room for my port in the middle. 12x12 port 8 inches deep at 49 hz Link to comment Share on other sites More sharing options...
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