jcody_parker Posted May 4, 2019 Report Share Posted May 4, 2019 Looking to build a box for lows in a 1989 Dodge Colt Hatchback with a Sundown X15 D2 V2. Not a huge fan of SPL just want to move a lot of air and play 14-19hz. I don't need a lecture on it, I just love the feeling and want to go that route with this build. Building a large box or a wall is not a problem, since the car is so small I figured I'd have to sacrifice the entire rear of the car or most of it at least. I'm fairly new to box design, but have been researching the past few months before building a box. I remembered that I used this forum to help with my last box about 6 years ago and loved the results with the help I got from here! Figured I'd give it a shot again. I was talking to a guy on YouTube, but he doesn't speak very good english. He is on 4K rms, I didn't think a single X15 could handle that much power in such a big box. I asked the volume of his box and port, and he replied to my comment and said "my box makes 170 liters internal (not counting the vent) and 240 liters in total. The frequency of tuned is at 20hz but in a larger vehicle the frequency rises to 28hz" I put all the parameters into WinISD and I could not get the port volume the same as what he mentioned. The only way I could keep the box at 20hz would be to make the port super long, or super skinny it seems like. Any help is appreciated! Thanks His Videos - Fast forward to 0:57 where he turns it up a little. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted May 4, 2019 Report Share Posted May 4, 2019 How much power are you going to be running? For the guy you posted above, putting 4K into that sub in a 6 cu foot box is definitely a risky proposition. The X-15 has a lot of cone excursion capability, but he is probably pushing his luck quite a bit, its not something I would do. There are a couple ways you could tackle this problem. In theory, a 4.5 cu ft box tuned to 17 hz or so would work great. However, as you found out, the port is going to have to be ridiculously long to the point its not practical and would create is own problems. Since a ported box isn't going to work, here are some other options, each has its own advantages and disadvantages. One would be a 4th order bandpass box. I'd make the sealed chamber as large as you possibly can while still keeping cone excursion at a safe level for the amount of power you are running. Another option would be to use a passive radiator, this would probably be the most elegant and effective solution, but its going to cost you a couple hundred bucks for a high excursion 18" PR (or possibly two 15" PRs). Just out of curiosity, what music are you playing that has content down to 14 Hz? I'd like to hear that for myself. "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...
DiBo Posted May 4, 2019 Report Share Posted May 4, 2019 14-19hz? Good Lord lol. You won't hear much but it'll definitely move some air lol. Triticum will definitely help you get there. Link to comment Share on other sites More sharing options...
Joshdashef Posted May 4, 2019 Report Share Posted May 4, 2019 Must be rebassed songs right ? Your average songs never go that low ? Interested to see how this comes out SMD Tool Map (2022): https://www.stevemeadedesigns.com/board/topic/220267-smd-tool-map-2022/ My Port Size Calculator (in progress): https://www.stevemeadedesigns.com/board/topic/217087-port-size-calculator-in-progress/ Common Port Walls for a Slot Port: https://www.stevemeadedesigns.com/board/topic/217076-common-port-walls-why-it-matters-to-your-box/?tab=comments#comment-3240313 Link to comment Share on other sites More sharing options...
jcody_parker Posted May 4, 2019 Author Report Share Posted May 4, 2019 6 hours ago, Triticum Agricolam said: How much power are you going to be running? For the guy you posted above, putting 4K into that sub in a 6 cu foot box is definitely a risky proposition. The X-15 has a lot of cone excursion capability, but he is probably pushing his luck quite a bit, its not something I would do. There are a couple ways you could tackle this problem. In theory, a 4.5 cu ft box tuned to 17 hz or so would work great. However, as you found out, the port is going to have to be ridiculously long to the point its not practical and would create is own problems. Since a ported box isn't going to work, here are some other options, each has its own advantages and disadvantages. One would be a 4th order bandpass box. I'd make the sealed chamber as large as you possibly can while still keeping cone excursion at a safe level for the amount of power you are running. Another option would be to use a passive radiator, this would probably be the most elegant and effective solution, but its going to cost you a couple hundred bucks for a high excursion 18" PR (or possibly two 15" PRs). Just out of curiosity, what music are you playing that has content down to 14 Hz? I'd like to hear that for myself. 4 hours ago, DiBo said: 14-19hz? Good Lord lol. You won't hear much but it'll definitely move some air lol. Triticum will definitely help you get there. 3 hours ago, Joshdashef said: Must be rebassed songs right ? Your average songs never go that low ? Interested to see how this comes out Yes I listen to all rebassed songs. Mostly the DJ Russticals and Decaf ASTRO collection. The car will mainly just be for demo's anyway, however it would be nice to see a decently high number for SPL. I understand that it's only one 15 so i'm not expecting anything too crazy. But there's plenty of videos with tons of flex from one X15. I'll be on 2000 RMS. I was thinking of doing a 4th order, but some posts on forums suggest a sealed box isn't ideal for the X15. I've looked a little into 4th orders but don't have a full understanding on how to design one, which is why I figured i'd just go for a giant ported box for now and build a 4th order once I get a second X15. I wanted to do an aero port just for being easily changeable, but im still stuck on how to tune this low without a massively long port. Unless its not possible? Link to comment Share on other sites More sharing options...
DiBo Posted May 4, 2019 Report Share Posted May 4, 2019 15 minutes ago, jcody_parker said: Yes I listen to all rebassed songs. Mostly the DJ Russticals and Decaf ASTRO collection. The car will mainly just be for demo's anyway, however it would be nice to see a decently high number for SPL. I understand that it's only one 15 so i'm not expecting anything too crazy. But there's plenty of videos with tons of flex from one X15. I'll be on 2000 RMS. I was thinking of doing a 4th order, but some posts on forums suggest a sealed box isn't ideal for the X15. I've looked a little into 4th orders but don't have a full understanding on how to design one, which is why I figured i'd just go for a giant ported box for now and build a 4th order once I get a second X15. I wanted to do an aero port just for being easily changeable, but im still stuck on how to tune this low without a massively long port. Unless its not possible? Not fond of aeroports. Slots are easy to tune and get exact port area you want. X series do good in fourth orders. Just not small 4th that are mostly enclosed... They do good in walls inverted so they can cool properly. 2.0 sealed and about 5.5-6ft³ ported with around 75in² of Port area would do well. You'd need at least 2k RMS after rise tho. Super simple to design actually. Link to comment Share on other sites More sharing options...
jcody_parker Posted May 4, 2019 Author Report Share Posted May 4, 2019 20 minutes ago, DiBo said: Not fond of aeroports. Slots are easy to tune and get exact port area you want. X series do good in fourth orders. Just not small 4th that are mostly enclosed... They do good in walls inverted so they can cool properly. 2.0 sealed and about 5.5-6ft³ ported with around 75in² of Port area would do well. You'd need at least 2k RMS after rise tho. Super simple to design actually. I just tried making a 4th order in WinISD with that box size but i'm still clueless on how it actually controls excursion, and what exactly is needed for the port size to move air. I've tried to look around for answers but not really sure which direction to go. Looking at the size of his port, I'm confused on how he has it tuned to 20hz without the port being like 4 foot long. Any reason in particular you don't like aeroports? I just figured I could try out 20hz, then if I don't like it, cut down the length of the port to tune higher. The box will be pretty long, so I'm sure i COULD fit a 8" diameter X 36" long port inside if needed. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted May 4, 2019 Report Share Posted May 4, 2019 The problem with an aero port is there is no way you are going to be able to get it long enough to tune below 20 Hz and still have enough port area. Totally impossible. If if you want to try a 4th order band pass box I can crutch some numbers for you when I get home. "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...
DiBo Posted May 4, 2019 Report Share Posted May 4, 2019 The port on a 4th order is for the higher frequencies. You usually tune to around the mid-forties. If you are trying to play really low I would tune to around 36-38 to play under 18hz. you don't get your Lows from the ported side Lows come from the sealed side. Link to comment Share on other sites More sharing options...
Kyblack76 Posted May 5, 2019 Report Share Posted May 5, 2019 Odd,.. adjusting the loading wall, lowered our "low" peak. ( Pushed it back) ( Psyclone competing) (4th order) ( ) SMD SUPER SELLER The Burban Build Blazer Build sold Acura trunk build sold Link to comment Share on other sites More sharing options...
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