Port rec for RSD Comp 10 in 0.7cF box

[lawrence131]

I have a Probox shallow 10" box that I really like for cosmetic and fitting reasons behind the passenger seat of my SL55 convertible. Black on black box and woofer on dark grey interior.

http://www.bicostereo.com/index.php?act ... uctId=5046

It looks better in person than in the picture and fits very well where I need it to, and is also very stiff and of great build quality (for a prefab). It is 0.7cF sealed so I have enough extra space to add an internal port and still keep the volume between the SQ and SPL manufacturer recs so I should get a balance between SQ and SPL. This is bigger than needed for the sealed recs so I want to try out ported just for fun of it since I have the space in this box to do so.

What size port would you guys rec? The manual indicates a 1.5 x ~6, but have you guys tried different ones that work better for this purpose? That Vd just seems small to me for some reason.

It's being powered by an Arc 1200.1 that benches over 1400 so power shouldn't be an issue.

Thanks.

[The Golden One]

the bigger the port the better well within reason given the port location and if it may contact the speaker magnet. a bigger port has less port noise than a smaller one but you need to make the bigger port longer. i usually go with a 3 inch on 12's so i think a 2.5 would work good for 10's also you may have to do some custom tuning to get it where you want it. i would'nt know the exact port length for what your doing but maybe someone else may can help a little better.

[lawrence131]

thanks, i think this will get a little complicated since the larger the port diameter, the longer the port length, and the more box volume I lose. this pushes it more toward the pure SPL volume requirement but I wanted it in the middle of SQ vs SPL.

also do you know if WinISD box volume is the total volume or the volume minus the woofer displacement?

[The Golden One]

i dont know if WinISD does that or not i used http://www.bcae1.com/spboxnew2.htm box volume calculator when i last built a speaker box but i called the speaker maker to find the actual volume of the speaker basket.

[Stryker]

here's the one i use
http://www.the12volt.com/caraudio/boxcalcs.asp#por
for a tune in the low 30's your gonna need a 2 inch port about 10" long, which may or may not have port noise. go punch in some numbers.

[stipud]

I wouldn't recommend going ported in that small of a box personally. The recommended SQ spec for ported boxes is the only one I would consider using in any installs, and even then I would go with a bigger box in order to use a larger 3" port. For some reason PG specs these tiny ports, which cause chuffing on low notes. No good!

0.6 sealed is about perfect for that sub. I would suggest dropping a small block of styrofoam in there to take up some .1cf airspace and run the sub sealed. It sounds best that way

[Stryker]

I wouldn't recommend going ported in that small of a box personally. The recommended SQ spec for ported boxes is the only one I would consider using in any installs, and even then I would go with a bigger box in order to use a larger 3" port. For some reason PG specs these tiny ports, which cause chuffing on low notes. No good!

0.6 sealed is about perfect for that sub. I would suggest dropping a small block of styrofoam in there to take up some .1cf airspace and run the sub sealed. It sounds best that way

exactly my thoughts as well.

[lawrence131]

thanks, that makes it much easier. I will just lose some low end extension based on the WinISD parameters going with 0.6 sealed but it will probably still sound better overall. 2 inch X 11 inch is what I came up with on WinISD as well for low 30s, but was concerned about the possibility of port noise on that size diameter.

I may just stick in the pre-made 2 x 11 parts-express port for fun to see what happens and seal it back up if it's bad.

[ttocs]

you can always add some low end with a bass cube...........

[Bfowler]

just a heads up, this sub already performs like a ported sub, the 20-40 range is louder then the 50-70.

so if you beef up that 30ish range with a port, you need some serious midbass!

[lawrence131]

bfowler - if I just leave it sealed as is in the 0.6 cF box there will be plenty of low's in the 20-40 range? The T/S parameters in WinISD show's the opposite - shows a large/steep drop below 60 Hz and that the 20-40 range has much less SPL than the 50-70 range.

going by the parameters, the 30ish range needs a boost, but real world experience > modelling programs.

[Bfowler]

is that graph accounting for cabin gains?

[lawrence131]

ahh, the graph does not account for cabin gain. i have no idea how to do that but will do some research.

[Bfowler]

you could use your normal graph, and pit the 2 subs against eachother

use a sub you are very familier with and just see how the rsdc curve looks next to it