2009 toyota corolla custom port slot box

suprfast wrote: How does one know how large of a box to make vs how long of a port. I ask because i have been plugging numbers into the calculator here on the site and it seems like one could make a huge box with corresponding port length tuned to the Hz one would want and still have too large of a box. Where would one find the happy median or magic numbers? I guess what im trying to say is, If i didnt have your help, which i am glad i do, how could i figure this out? kris

Well that is kind of the trick to designing ported enclosures. There is no way to do it other then messing around with different configurations until you get an enclosure that will work the best. It involves a lot of trial and error until the best design is determine. I personally always use a CAD program such as SolidWorks. This allows me to make slight adjustments in the design until I get what is required or what works the best. When I design an enclosure I start with finding out the best internal volume and tuning frequency for the sub being used. So before I even start making my design I know what internal volume I need, the tuning frequency I need, and the maximum dimensions I have available. Once that is determined I start my design in a CAD program. I plug in some initial values that are within the maximum dimensions available. I will make an "ideal" design which is typically a very large port. Then I modify the design until it meets my internal volume requirement. If this design is too large then I will modify the port and make it smaller which makes it shorter. I will do this until I finally figure out a design that will work. Sometimes it will require taking away internal volume or going with a smaller for in order to get the specs I need. There is usually a give and take in a design. Unless you have a huge amount of area to work in you will have to give up a little something in the design. I don't know if this is what you wanted to know but this is how I typically design an enclosure...

whiterob wrote: When I design an enclosure I start with finding out the best internal volume and tuning frequency for the sub being used. So before I even start making my design I know what internal volume I need, the tuning frequency I need, and the maximum dimensions I have available.

Your first sentence is what im looking at. Apparently these sub manufactures (speaking on alpine particularly) claims that a 1.25 CF is ideal. Yet everyone i talk to and trust more than alpine says that a 2-2.5 cf box is the goal for the 12" type R. How do we know if the claim by alpine is rubbish? Is this what the calculators are doing for us with the Xmax, depth, numbers, etc? Thank you again. kris

suprfast wrote: Your first sentence is what im looking at. Apparently these sub manufactures (speaking on alpine particularly) claims that a 1.25 CF is ideal. Yet everyone i talk to and trust more than alpine says that a 2-2.5 cf box is the goal for the 12" type R. How do we know if the claim by alpine is rubbish? Is this what the calculators are doing for us with the Xmax, depth, numbers, etc?

Well people that design enclosures will use enclosure designing software. If you use this software you can see that a larger enclosure that is around 2 cubic foot is going to be a bit better then Alpine's recommended enclosure. This does not mean Alpine's recommended enclosure is bad. In fact, I can easily see why they would give those recommendations. Alpine is a large manufacturer which means they want to appeal to the largest audience they can. Most people don't want to have a large enclosure in their car. For this reason Alpine recommends a smaller enclosure. Alpine will also recommend that enclosure because it is fairly forgiving. You can be a little off on the specs either way and not have a huge difference in overall performance. I know that Alpine says that a 1.25 cubic foot enclosure is "optimum" in the manual. The truth is that there is no such thing as an "optimum" enclosure. The best enclosure design will depend on your own space available and your own type of performance. So if you are looking for something that is good for output you would have a different enclosure then you would if you were looking for sound quality. So the "ideal" enclosure is the one designed specifically for your own taste.

Thank you whiterob, i appreciate all the input. Helped me greatly. kris