Box for atomic apxx 18

[raptor727 10+ year member]

So I just made a deal for some apxx 18's and have never used atomic before so I am pretty lost when it comes to a box design for these... For now it will be a single apxx on a ampere 3800.1. I have tried google and only seen someone reccomend 5.5-7.5 and tune around 35hrtz.. I suppose these don't like lower tuning so I am going to try 34.. Any advice on sq inches of port area or optimal cubes would be greatly appreciated thanks for your time.

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[72Impala 10+ year member]

atomic speakers

Try that sheet, if you don't see apxx on there you can go with apx tuning.

I would say 32-34hz is good, and I would go above 6 cubes per woofer, in regards to lows, that is a misconception, they will get low, you just need the airspace and power for it.

 

[will3 10+ year member]

7ft3 w/95sqin tuned around 33hz would be a good place to start with the APXX 18 , is this the 4" coil or 3" coil APXX

 

[72Impala 10+ year member]

7ft3 w/95sqin tuned around 33hz would be a good place to start with the APXX 18 , is this the 4" coil or 3" coil APXX

He has a 856 motor on it, he got it and another spare 856 motor from me.

 

[akadj 10+ year member]

I just built a box for two Atomic 18" with the 856 motors.. but buddy had NO room. The box is 40×18×24 with four 4" ports tuned to 35hz.. There was just no room in his car. It was a little Hyundai hatch back and they had to stay in the hatch area. But they really got down and were slamming off of just 1200 watts each! Once he puts more power to them and they really start moving they will need more port area FOR SURE.. But its good for the mean time with the power he's got going to them.

I'm going to throw it on the meter on January 6th when I get back home

 

[raptor727 10+ year member]

I just built a box for two Atomic 18" with the 856 motors.. but buddy had NO room. The box is 40×18×24 with four 4" ports tuned to 35hz.. There was just no room in his car. It was a little Hyundai hatch back and they had to stay in the hatch area. But they really got down and were slamming off of just 1200 watts each! Once he puts more power to them and they really start moving they will need more port area FOR SURE.. But its good for the mean time with the power he's got going to them.
I'm going to throw it on the meter on January 6th when I get back home

lol I know what you mean I got a 1998 Mustang GT these are going in and it has turned out to be a ******.. Took out the back seats and everything and I still don't know if I have enough room for the box I want to do.. And yes they are the 3" coils..

 

[raptor727 10+ year member]

ok not going with atomics plans on the website just seems like too little of port area and I just think it would be peaky... Going with 95sq in of port tuned at 34 I think... And 6.75 after displacements unless anyone has any ideas..

 

[raptor727 10+ year member]

ok now trying 7.5 cubes I am soo **** lost lol.. power is 3500rms give me some ideas for daily folks this is driving me nuts!!

 

[akadj 10+ year member]

Edit

 

[akadj 10+ year member]

Only thing I can tell you with out being there to see the vehicle and dimensions to work with is that your port should be 1/3 of the surface area .

I've never been one to use the 12-16 sq" of port per cubic foot because your port area is not a variant to box size, port length is. Your port radiates sound and needs to be built accordingly to Xmax and surface area. To small of a port for your woofers and the air your trying to move will essentially just be a "leaky sealed box".. So i suggest a pair of 18" woofers should have a port no smaller then 150 sq"