[mjg100]

Looking at making a box out of 3/4" MDF. Planning on making ported sub using Shiva-X driver and 4" port. Front baffle will be 1-1/2" thick. All other sides 3/4" thick. I am looking at this size: 19-7/8" height, 23-1/4" wide and 23-1/4" deep. I can go larger or smaller, but I would like to use this size if it models well because this size will match a sub that I already have. Other sub is in another room, but I would be able to switch them if I wanted if they are the same size. This sub will be used in a 1,200 CF treated room. Sub to be front firing with 4" port on the front baffle. Cabinet will be braced. I plan on using a notched brace across the back running horizontally and one or two braces across in the middle. Now for my questions.


1. Should I place one brace across the middle or should I use two braces?

2. I have read that the 300 watt Bash amp will work well. Should I use that or

would I be better off using 500 watt Bash amp?

3. How long do I make the 4" port for tuning. Sub will be for HT use.

4. How much poly fill do I use, where is it placed and is it secured in any

way?

5. Does this model well?

6. Should I do something different?


Thank you for your help.

 

[lennon_68]



Quote:
Originally Posted by mjg100 /forum/post/15505603


1. Should I place one brace across the middle or should I use two braces?

2. I have read that the 300 watt Bash amp will work well. Should I use that or

would I be better off using 500 watt Bash amp?

3. How long do I make the 4" port for tuning. Sub will be for HT use.

4. How much poly fill do I use, where is it placed and is it secured in any

way?

5. Does this model well?

6. Should I do something different?

1. The more bracing the better (within reason). If you can add that brace without too much more cost/effort go for it.

2. The Shiva in a ported box that size can handle the 300W or 500W amp - that won't be the limiting factor here.

3. That depends on what you want to tune to. You should download Unibox or WinISD and run some models. The longer the port the lower the tune

4. You shouldn't need much poly fill in that size box

5 (and 6). For the most part this models well. The major limiting factor here is the 4" port. I don't think that will be enough port area for what you're trying to do - it looks like chuffing could be a major issue down around 18hz or so. Although I still don't have a great idea of how bad chuffing will be as I look at a graph but it shows the air speed with 300W and a 20Hz tune (~12" long port) getting up to a peak of 43 m/s at 18hz.

 

[mjg100]



Quote:
Originally Posted by lennon_68 /forum/post/15506620


1. The more bracing the better (within reason). If you can add that brace without too much more cost/effort go for it.

2. The Shiva in a ported box that size can handle the 300W or 500W amp - that won't be the limiting factor here.

3. That depends on what you want to tune to. You should download Unibox or WinISD and run some models. The longer the port the lower the tune

4. You shouldn't need much poly fill in that size box

5 (and 6). For the most part this models well. The major limiting factor here is the 4" port. I don't think that will be enough port area for what you're trying to do - it looks like chuffing could be a major issue down around 18hz or so. Although I still don't have a great idea of how bad chuffing will be as I look at a graph but it shows the air speed with 300W and a 20Hz tune (~12" long port) getting up to a peak of 43 m/s at 18hz.

What can i download and run on a MAC?

 

[lennon_68]



Quote:
Originally Posted by mjg100 /forum/post/15507879


What can i download and run on a MAC?

If you're lucky Unibox will work on your mac (it's a Microsoft Excel spreadsheet)... I'm not lucky (it doesn't work on my mac at home) so I have to model on a PC at work