Question about Modeling RL-P15

[dsl1]

For Christmas I received a Soundsplinter RL-p15 sub and am looking forward to building a sonosub.


I went ahead and purchased a 4.5ft length of 24in sonotube for 40$ from the local concrete place. Unfortunately, I now realize if I go with the classic 260-265L enclosure with a ~25inch length 6inch diameter port the driver would be touching the end of the port.

I posted on avsforum and was told I could increase the enclosure size and should model it in winISD. I went ahead and put in the data for the duel 4ohm rl-p15 and this is what I came up with. The lumps look kinda weird to me but I am not sure what the ideal look should be. Any help would greatly be appreciated.


350 Liter's at 18hz. I would be fine with this size as the port wouldn't even be close to the driver anymore.

Image not available

For reference here is the 265L model. Hopefully will show if my driver numbers are weird if this one looks off.

Image not available


Thanks in advance :T

[ThomasW]

The plots you see are anechoic simulations, not what the sub will do in a real room. In a real room the lower frequencies are filled in by room gain. So the dip (saddle) in the 350L plot is filled in when the sub is operated in a room.

[dsl1]

The plots you see are anechoic simulations, not what the sub will do in a real room. In a real room the lower frequencies are filled in by room gain. So the dip (saddle) in the 350L plot is filled in when the sub is operated in a room.

Okay great. So 350L should be fine? If I tune it lower in winISD it drops off at a much sharper rate. Is it possible for you to say how much lower I could tune it and have room gain balance it out? 14ft wide 8ft high 22ft long carpeted basement with drywall.

I would like to to go as low as possibly smoothly, but am not sure where that point is. I can go 350-375L no problem.

Thanks in advance. I'm off to Menards to grab MDF, pipe, black paint, etc... :T

[dsl1]

Got everything except the bolts for the driver. Can't seem to find any button head ones that are 4inches long Will figure that out tomorrow. Any idea what I could get?

Any ideas on what volume it should be and what I should tune it to?


Thanks

[---k---]

I just use drywall screws to hold my RL-P15 in place. I've done the t-nut thing, and broke a few loose. Lots of people here just say to use a drywall screw, so that is what i did and it is working fine.

Several people have built RL-p15 sonosubs with 320L and somewhere around 15hz tune. That is Steve Callas's typical recommendation. Do a search for the exact numbers - shouldn't be hard to find one.

[ThomasW]

Okay great. So 350L should be fine? If I tune it lower in winISD it drops off at a much sharper rate. Is it possible for you to say how much lower I could tune it and have room gain balance it out? 14ft wide 8ft high 22ft long carpeted basement with drywall.

I would like to to go as low as possibly smoothly, but am not sure where that point is. I can go 350-375L no problem.

The lower the Fb the greater the saddle. The greater the chance that room gain will not fill it in.

Room gain depends not only on the geometry of the room but how 'lossy' (flexible) the room is. So rooms with lots of doors and standard drywall construction will have less room gain than a room with stiffer walls (like a basement) and fewer doors.

Several people have built RL-p15 sonosubs with 320L and somewhere around 15hz tune. That is Steve Callas's typical recommendation. Do a search for the exact numbers - shouldn't be hard to find one.

The person primarily responsible for starting the trend of people using the RL-p15" for home subs is posting in this thread. As a result I don't think the OP needs to look elsewhere for guidance.....

The OP's limiting factor for how low he can tune, with be the length of his tube in relation to the length of the port.

[---k---]

The person primarily responsible for starting the trend of people using the RL-p15" for home subs is posting in this thread. As a result I don't think the OP needs to look elsewhere for guidance.....

Yep, you are correct. I just couldn't remember offhand you giving adivce on one this big. I saw the 350L, and it seemed like there have been a few recently that he could copy. I must have missed how he is going to have trouble fitting the port in. 15hz is around 39" long, so I would think that would just fit in a 4.5' long tube. I must be missing something, so I'll hang up now and listen to your comments.