Rockford Sub Box Rebuild

[old skool malibu]

Thanks everyone for your help. After much discussion I think i will go with a new sub and amp as well. The Xi12DVC and Xi500.1 should be a wee bit of a step up over stock. If I am going to the effort to build a box might as well have some good gear in there. Any recomendations of box size would be appreciated. I want to keep with a sealed enclosure and I am after a consistent punchy sound not a one note wonder.

[Earmark Marine]

old skool,

Here is the answer to the PM you sent me. It should be useful to anyone doing the same thing with any woofer regardless of brand or series.

When running a sealed enclosure it will be a box that is too small that will create more peak output but will also create more of a 'one note wonder' as you called it. A box that is too small will seriously attenuate the lower bass fundamentals and you will miss important material.

A larger enclosure will create deeper bass extension but the bass will be generally non-descript in its tonal construction when you go too far in pursuit of deep bass extension. You will also sacrifice some power handling at either extreme but in particular with a box that is too large.

As stated before, you want to model the enclosure based on the Thiele Small parameters so that you end up with a balanced Qtc (system 'Q' with the woofer loaded in the box) which is a resulting Qtc of between 0.7 and 1.0. An ideal balance would be a Qtc of 0.8 to 0.85. A rule of thumb or shooting from the hip will not give you the correct box size with any degree of precision. Get this recommendation out of the realm of subjectivity and do it by the numbers. If the specs are accurate then the results will be accurate.

At first glance a good internal enclosure volume for the woofer you referenced might be around 1.3 cu.ft. net (after the woofer displacement) based on a large signal calculation. You want to go to either your local ME dealer or the product manufacturer who should run the specs on a good in-house computer program rather than the primitive on-line calculators.

David

[Bobby Light]

As I told you via PM 1.25 cu ft after displacements is a real world experience tried and true box size for that sub.

[old skool malibu]

Thanks gents. Sounds like 1.25-1.3 is roughly the way go go! I have a pm into Brian to get the specifics. I really have no idea at this point on the Qtc etc but I am sure Exile will point me in the right direciton.

Edited February 28, 2012 by old skool malibu