Time delay between vented and sealed ?

Deadof_knight

Ok im trying to tune my two subs together one is a 15 inch velodyne, the other is my DIY model with a fosgate 18 xlc in 4 cuft box with a dayton 1000 hpsa for an amp. 18 is sealed 15 is vented. Isnt there a phasing difference between sealed and vented or group delay ? I also think my box might be a tad big. Ill post dimension later today and pics.

ShinAce

Vented does introduce a group delay but it varies with frequency, sub parameters and box design. It gets worse as your approach the lower end(the tuning frequency).

There is no universal adjustement that you can make to match the subs(unlike crossover phase). Either the mixed sound will be satisfactory, or it won't. It's up to you to decide.

Deadof_knight

I guess I will port the thing then and then the can both be the same , and this will all be easier ...... PNR port 4 inch

ShinAce

Don't worry about it honestly. I can't recommend porting that Velodyne as a solution to a problem that does not exist.

If you have a variable phase control on one of the sub amps, set it to 30 degrees or 330 degrees as a start.

Deadof_knight

No its my DIY er 18" its running sealed Im running 1.2s full range with my 15" velodyne. both subs are on a wall 90 of the 1.2s when i put the 18 on the same plane or wall as the 1.2s or the 15 its BOOOM time when i put them both its not so ive got some cancellation going on between the 3 the 1.2s the 15 and the 18.

My thinking was that I use the 15 like I have been add the 18" sealed for a real deep rumble bass. The amp on the 18 is a Dayton hpsa plate. The phase on the Hpsa only does normal or reversed (180 out) my velodyne does a full swep of phasing change from 0 to 180 . Im going to play with it all day saturday probably. I still have to cover it in formaica to finish it but so far the box has turned out great. at 4.66 cubes sealed I still have enough room to port if i want and it will be at the upper end or half way point at 4 cubes thats the largest sealed but I used items to take up space ....too hard to create space but you can always take up some with bags of sand or shot. The 18 say it needs 3.5 to 5 cubes ported and I will be at about 4.15 to 4.25 if my figures are right.

ShinAce

You need to look at moving the subs around for best performance.

Phase will only serve as a bandaid.

Deadof_knight

HAHA well by moving the sub where I cant have right next to my 1.2s the sub is just killer pounds the room had to turn it way down infact. So now I gotta start moving around today and listening