Best box for type r's?

[99FirebirdSPL]

I'm about to order 2 type r 12" and the box im using right now is 4.5cf@38hz which wont work. I'm leaning towards vented or ported, but i'm not too good with the math involved in tuning and such.
Anybody have the new type r's in a ported box?

Just trying to find the right box design. thanks

[96firebird311]

Re: Best box for type r's?

4.5 cubes is fine for two 12" Type-Rs. 38Hz is tuned pretty high....but hell... try it out. If you decide it's a little too peaky you can add length to the ports (couple few inches) to lower tuning frequency. If that's impossible, then you'll just have to build another box.

[99FirebirdSPL]

Re: Best box for type r's?

i thought the 12" R's took 1.75cf each. And I doubt I'll be able to make the ports on my current box longer, I cant really explain but i'll post some pics of my box sometime today.

[96firebird311]

Re: Best box for type r's?

Manfacturer's suggestions are so extremely vague it's not even funny. I honestly believe they just put those numbers out there so people will stop emailing/calling them asking "what size box should I use?"

Making a box larger or smaller has different effects on subwoofer performance. You can usually go quite a bit larger than "recommended" before the sub preforms as if it were in a free-air setup. (like your door panels) Surely you could go clear up to 7-8 cubes with two 12" Type-Rs. Next, I bet that's 4.5cubes before sub displacement and maybe port displacement? Making the end result, smaller.

Anyway, it's not going to hurt anything to throw them in the box you have now to test them out. I've already modeled up the charts for what it might sound like. If you think I'm lying to you....(donno why I'd waste my time on here day in and out).... I can post up the graph from you.

[99FirebirdSPL]

Re: Best box for type r's?

i guess i will I just need to fix the design flaw on the box which is that the top port tube had to have the back of it cut at an angle to fit, god knows what its really tuned to. I'd also like to separate it to 2 chambers. And yes 4.5 before sub displacement and port displacement. that was as big as i could go. when its tuned higher than suggested doesn't it start to ruin sound quality, but get reasonably louder at a certain freq range? I've heard that competitors usually tune their setups pretty high for burps.
Im actually looking at these now:
http://www.realmofexcursion.com/vide...emier12.23.wmv
lots of movement

[95Batmobile]

Re: Best box for type r's?

Ported and 2 chambers will be difficult to do correctly and is not really necessary.
People in comps usually port in the 40-50hz range, but it is different for every setup. 38hz is on the high end for a daily driven car, but a lot of people actually do it. You should try it and see if you like it. If there isn't enough low end you can try a 32-35hz tuning.

[96firebird311]

Re: Best box for type r's?

Ported and 2 chambers will be difficult to do correctly and is not really necessary.
People in comps usually port in the 40-50hz range, but it is different for every setup. 38hz is on the high end for a daily driven car, but a lot of people actually do it. You should try it and see if you like it. If there isn't enough low end you can try a 32-35hz tuning.

QFT. Like I said.... again.... there is no harm in trying it out. Thats step one.

Oh and for the record, many pre-fab ported boxes that come with alot of MTX, Kicker,etc subwoofer systems are tuned right around 35Hz. People buy those all day long and are happy with them. So it's not a big deal if, infact, it IS tuned to 38Hz.