RL-P box redo

[BLD 25 10+ year member]

Hey, i have an original RL-P with the following T/s:

Fs:21.29 Hz

Qe:0.24

Qm:2.72

Qts:0.22

Vas:72.60 ltr

Sd:0.0471 m^2

Bl:20.05 N/A

Xmag:26.0 mm

Xsus:24.2 mm

Xmax:24.2 mm

Mag Maximum:0.4 mm

Sus Minimum:1.4 mm

I currently have it in 1.6 net ported around low 30's. I contacted mike at SS about a 15, and he said that if i built a new box for this one and bumped it up to 2.0 cubes at around 28 i would gain low end, and if i did 2.0 at 34, i would gain output. questions:

1)would i also gain output going to 2.0 at 28, or just lowend.

2)How much output would i gain going to 2.0 at 34hz over my current setup?

3)will i lose much sq in either situation?

thanks!

If anyone has any suggestions as far as box parameters, etc, that would be awesome. My only restriction is 14.5" high, and i don't want to be deeper than say 16-18".

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[mlstrass 5,000+ posts]

I can only offer up what I found out testing/building boxes for my RL-P 15's. 32Hz seemed to be the magical spot for SQL. 34Hz lost some of the lows/impact and 30Hz hit low/hard, but not as much output.

I'd try it at 32Hz, not sure about box size, but usually the bigger the better for low end...

 

[itzme218 10+ year member]

****, you got good ears. never knew someone can tell the difference between 30hz 32hz and 34hz. 30hz to 34hz yeah maybe, but come on 2hz difference you can actually tell?

 

[BLD 25 10+ year member]

so would i gain output or lose sq, etc?

 

[mlstrass 5,000+ posts]

****, you got good ears. never knew someone can tell the difference between 30hz 32hz and 34hz. 30hz to 34hz yeah maybe, but come on 2hz difference you can actually tell?

Well I don't profess to have "great" ears, but I play the same 8-10 songs off a demo CD I burned, so I know the source material VERY well. Also I took into account how much things shook/vibrated in the car. Obviously it wasn't a scientific test //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

But 2 guys I work with that have heard my set up numerous times, gave me pretty much the same exact feedback. And I didn't tell them anything other than I built new boxes. They both noticed how the 34Hz tune just didn't hit as hard as it did before. One guy still swears that 30Hz was the loudest/hit the lowest, but to my ears 32Hz seemed to be the sweet spot.

 

[mlstrass 5,000+ posts]

I'd go for 2.0 @32Hz going by what mine sounded like at 34. SQ wasn't bad, just not as good. Almost sounded hollow on some songs, just not at tight and pronounced on kick drums, etc...

Going bigger should help with the lows and 32Hz should give you more output while still sounding very good.

And it's only a hunk of MDF and some time, so give it a try and see what you think.

 

[BLD 25 10+ year member]

thanks, i may try to stick with 34 since that is what the owner suggested. i can always do a longer tube to go to 32 if i need to.

here is what i am looking at now:

I searched a ton and read up on ports, square inches of port area, etc, and i used various calculators. I used the calc on maximacar.com, which is the best i have seen.

The box dimensions are:

24x14.5x15 with a 4 inch by 11" port. The calculator takes into account woofer displacement and displacement of the port, and it comes out to 2.29gross, and 2.06 net. With the box being 15" deep, that leaves 3.25" of space between the back of the inside of the box and the port, which i would assume is enough since it will be coming from all angles.

I know many people will say the 4" port may not be enough, but i have read that using a round port since it doesn't have corners, etc, you don't need as much port area since the are flows smoother.

does everything look good? will i gain much output?

Thanks!!

 

[mlstrass 5,000+ posts]

Isn't a 4" port around 25^2? That would be fine for a 12" sub in 2 cubes....

 

[IonSQL 10+ year member]

Isn't a 4" port around 25^2? That would be fine for a 12" sub in 2 cubes....

No, a 4" port is ~12.5 sq in....

 

[BLD 25 10+ year member]

is it worth a try to use one 4"?