Material options for sub box

[Gravy]

I am a newbie to both the this site and speaker building, so I apologize if these are ignorant questions.

I have been strongly considering building a kappa perfect sub similar to the designs posted, and had about a million questions, but I will try to keep it to a minimum

Initially I was wondering if a box constructed out of aluminum or steel rather than plywood would work. I was thinking I could make a much more efficient port (enclosed oval port all the way) as well as save a lot of space in bracing and material thickness. Any thoughts?

Also, a huge thank you to everyone here for the friendly and knowledgeable information that is so prevalent.

 

[lsiberian]

I am a newbie to both the this site and speaker building, so I apologize if these are ignorant questions.

I have been strongly considering building a kappa perfect sub similar to the designs posted, and had about a million questions, but I will try to keep it to a minimum

Initially I was wondering if a box constructed out of aluminum or steel rather than plywood would work. I was thinking I could make a much more efficient port (enclosed oval port all the way) as well as save a lot of space in bracing and material thickness. Any thoughts?

Also, a huge thank you to everyone here for the friendly and knowledgeable information that is so prevalent.

I can't suggest this option as the sub would be overly resonate IMO. Use Cabinet grade Birch Ply or MDF. I suggest Birch for subs because of their size. But I'm sure in practice either would work well. you could potentially use concrete, but seriously if you are even asking these questions I don't think you have the expertise yet to experiment with other building materials. The Port is best the way it is and has very little rear port velocity. There is no need to improve it.

 

[highfigh]

Pioneer made a limited run of 3/4" plexiglass HPM-100 and they sounded really strange. SFZ was a small company that used 1/2" limestone and they sounded strange, too. Both materials still resonated.

I recently saw a brand that uses Corian and that's a material I have considered using for a long time, but they don't sell it on a cash & carry basis because of the product warranty. Can't even buy it because they won't accept a waiver. MDF and cabinet grade plywood are still some of the best and reasonably priced materials.

 

[Gravy]

My thinking was that I could easily make the box resonance frequency outside the driver functional frequency range and if necessary add dampening to the box.

As far as the port goes, I was thinking that getting rid of the 90 degree turns would improve the port flow efficiency reducing turbulance and therefore reducing distortion. If the port has very low velocity, is there any reason not to reduce it's cross sectional area (and length to maintain the same tuned frequency) resulting in a smaller enclosure with the same volume in the sealed chamber? I understand there is a port flow velocity value that you do not wish to exceed due to turbulance issues, but as long as you are below that throughout the operating range of the driver what is the benefit of a larger port?

 

[lsiberian]

My thinking was that I could easily make the box resonance frequency outside the driver functional frequency range and if necessary add dampening to the box.

As far as the port goes, I was thinking that getting rid of the 90 degree turns would improve the port flow efficiency reducing turbulance and therefore reducing distortion. If the port has very low velocity, is there any reason not to reduce it's cross sectional area (and length to maintain the same tuned frequency) resulting in a smaller enclosure with the same volume in the sealed chamber? I understand there is a port flow velocity value that you do not wish to exceed due to turbulance issues, but as long as you are below that throughout the operating range of the driver what is the benefit of a larger port?

If you want to undertake this project in an experimental fashion. I suggest you do a lot of research.