abdc Posted February 9, 2020 Report Share Posted February 9, 2020 This is the beginning of a build log for a crazy large enclosure for a Sundown X 15 ------------------------------- After using this sub for my daily driver, with close to factory recommended specs at 4.36 cu.ft (and a bit larger than recommended port area at 81in2) I have become obsessed with this driver for its seemingly bottomless mechanical limits. So, I want to make a super huge, super efficient enclosure to really max out this sub, while still keeping limits within reason on paper. Net Volume 9.81 (roughly 2.25 X recommended enclosure volume) Tuning 32hz F3 26.84hz Port Area 100.53 (2 8inch bigass ports) Max Air Velocity 22.891m/s at tuning with max rated power 1500 Port Surface Area 1055 in sq Max xmas 15.632 (of available 30mm) at 37hz ... So I know what you are all thinking... 'really? 10 cubes for a 15? no way'... I know, but I'm convinced this sub will eat it up, here is my thinking. 1) During free air test I put 1900 watts through this X-15 and I can't seem to bottom it out full sweep 2) On paper, I'm only using half of the available Xmas under full power 3) Group delay remains under 50ms at tuning. Generally you don't get the 'boomy' effect of super large enclosures until 77+ms at tuning, so I am still within the realm of solid bass reproduction (on paper) 4) LAST BUT NOT LEAST: At only 800 watts, I will be exceeding SPL output of my current 'manufacturer recommended' enclosure at 1500 watts along the same frequency curve So, all of that being said, has anyone here done testing on the Sundown X 15 in ultra large enclosures? Just HOW stupid is this project Link to comment Share on other sites More sharing options...
Ron36 Posted February 9, 2020 Report Share Posted February 9, 2020 Seems like a waste of time if your building a box to fit 2 15’s , just by another 15. The manufacturer makes specs for a reason, U have a great sub Y try to beat it up and distort it to death . Don’t understand how it will sound better in a box way to big then it’s made for but it’s your time and money.I bet the Xmas drops on a box that big. 2022 Ford Maverick on 22’s Skar SK1500.1 on 4 Skar VD-8’s Mids Sundown Super tweeters, Skar TX 6.5 components on Skar SKM400.4 LC2 for audio control , XS Power D680 XS Series Extra Battery Link to comment Share on other sites More sharing options...
abdc Posted February 9, 2020 Author Report Share Posted February 9, 2020 6 minutes ago, Ron36 said: I bet the Xmas drops on a box that big. Not on the model. That is why I am so curious. And if it doesn't, it shouldn't distort to death. But I definitely understand the sentiment, this is purely for testing purposes. Using inexpensive materials. I did have a DD 15 on 9 cubes with great success before so I am trying to see if this one another rare driver that performs well despite being relatively near IB environment. Link to comment Share on other sites More sharing options...
Ron36 Posted February 9, 2020 Report Share Posted February 9, 2020 DD is on another level but good luck. 2022 Ford Maverick on 22’s Skar SK1500.1 on 4 Skar VD-8’s Mids Sundown Super tweeters, Skar TX 6.5 components on Skar SKM400.4 LC2 for audio control , XS Power D680 XS Series Extra Battery Link to comment Share on other sites More sharing options...
abdc Posted February 9, 2020 Author Report Share Posted February 9, 2020 Yeah thanks man. I'll post results and you get fulls rights to throw me an 'I told you so' if this ends in a re-cone. Distortion isn't really a product of relative enclosure volume unless you are reaching mechanical limits. Manufacturers recommend box sizes for the overall Q value of the system as well as keeping volume in line with the recommended port area at rated power, but depending on your needs the values you are looking for in practice may vary. Sundown does advertise safe use of their X series products up to 1.5 times the recommended volume right on the product page for example. I know I am going beyond this, but just wanted to point that out. Thanks for the feedback! Link to comment Share on other sites More sharing options...
Ron36 Posted February 9, 2020 Report Share Posted February 9, 2020 Post some videos now I’m interested in seeing if Xmas is increased or decreased with that box. Also if possible the DB change. 2022 Ford Maverick on 22’s Skar SK1500.1 on 4 Skar VD-8’s Mids Sundown Super tweeters, Skar TX 6.5 components on Skar SKM400.4 LC2 for audio control , XS Power D680 XS Series Extra Battery Link to comment Share on other sites More sharing options...
shredder2 Posted February 9, 2020 Report Share Posted February 9, 2020 4 hours ago, abdc said: This is the beginning of a build log for a crazy large enclosure for a Sundown X 15 ------------------------------- After using this sub for my daily driver, with close to factory recommended specs at 4.36 cu.ft (and a bit larger than recommended port area at 81in2) I have become obsessed with this driver for its seemingly bottomless mechanical limits. So, I want to make a super huge, super efficient enclosure to really max out this sub, while still keeping limits within reason on paper. Net Volume 9.81 (roughly 2.25 X recommended enclosure volume) Tuning 32hz F3 26.84hz Port Area 100.53 (2 8inch bigass ports) Max Air Velocity 22.891m/s at tuning with max rated power 1500 Port Surface Area 1055 in sq Max xmas 15.632 (of available 30mm) at 37hz ... So I know what you are all thinking... 'really? 10 cubes for a 15? no way'... I know, but I'm convinced this sub will eat it up, here is my thinking. 1) During free air test I put 1900 watts through this X-15 and I can't seem to bottom it out full sweep 2) On paper, I'm only using half of the available Xmas under full power 3) Group delay remains under 50ms at tuning. Generally you don't get the 'boomy' effect of super large enclosures until 77+ms at tuning, so I am still within the realm of solid bass reproduction (on paper) 4) LAST BUT NOT LEAST: At only 800 watts, I will be exceeding SPL output of my current 'manufacturer recommended' enclosure at 1500 watts along the same frequency curve So, all of that being said, has anyone here done testing on the Sundown X 15 in ultra large enclosures? Just HOW stupid is this project I always thought 2 8" BAP is 98in2 of port area, and going that big on volume (9.81ft3 net?) will probably be super-peaky and a one note wonder. But hey... test and let us know your impressions... tuned in. Link to comment Share on other sites More sharing options...
abdc Posted February 9, 2020 Author Report Share Posted February 9, 2020 11 minutes ago, shredder2 said: I always thought 2 8" BAP is 98in2 of port area You are right! My math was at 8 inch diameter, however BAP 8s are actually 7.91 diameter. This makes internal surface area slightly more efficient at 1042.7in2, and adjusts enclosure volume to a slightly smaller 9.62 to maintain the same 21inch/port length (max length within available dimensions). Yes, net volume lol. Thanks for the reminder! Link to comment Share on other sites More sharing options...
abdc Posted February 9, 2020 Author Report Share Posted February 9, 2020 Oh it will certainly be a one note wonder in terms of SPL around tuning, but otherwise I expect the response to be flat enough. If I wanted an sq flat system I would probably have to go with a C4/SC4 alignment on low power and the enclosure would be absurdly small. But that's just not what this driver was made for. I am a little concerned about air velocity at tuning, but considering the flared round ports I think port noise should be kept to a minimum, but I'm sure I will experience some SPL loss to compression at tuning. Anyway, here are the graphs. I start building in the morning, will keep ya updated. And getting an SPL Lab meter this week so I should be able to get some accurate comparisons. Here are the WinISD comparisons of this build vs my current setup with manufacturer recommended specs. Green = Big Box Test SPL Transfer Function Magnitude Air Velocity Cone Excursion Link to comment Share on other sites More sharing options...
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