SUB Box- Ported or Not?

[16vStyle 0]

I'm currenty doing a boot build with a 10" Sub, and was wondering whether to port the box or not. I have not had a ported box in the past and have always had decent bass.

what difference does porting the box make? and are there any advantages or disadvantages to porting?

Appreciate any advice

 

cheers

[forcefed_vw 0]

You need the "Theile Small" parameters for the specific bass driver. They will tell you about the internal volume of the enclusure, the length and diameter of the port etc. Some units don't need a port, it all has to do with the deisgn of the voice coil, the materials that make up the cone etc. When deisigned the enclosure there are some basic rules, ported or not. Try to limit the number of parallel sides, these cause internal reflections will tend to make the bass notes 'hang'. Make the MDF as thick as you dare and reinforce the long sides with internal bracing (you can use a pice of MDF with large holes cut into it screwed across the enclosure). Use glue as well as screws, the enclosure must be airtight (except fot the port).

[Pete 0]

Sound advice by Forcefed.

 

Don't make a cube, indeed try to make all the panels different sized and, if poss, different thicknesses too!

 

Dynamat/brown bread the inside of the box too to damp it down.

 

Lots depend on the sub and amp used, but rule of thumb is a sealed box will go louder and ported goes deeper.

 

You could also make a bandpass box which will produce tighter "hifi" bass.

 

Sealed needs real meat and an amp to match, the ported design is easier to handle.

 

Pick your sub, and get the facts from the manufacturer, they will tell you the ideal volume of the enclosure and whether the sub os for sealed or ported boxes.

 

Then get screwing! :D

[corradokid 0]

Pete, what difference does making the panels different thickness's make?

 

Sealed boxes are usually better for tightness and punch, they also usually drop lower. The idea of a ported box is to increase the level at a certain point, which means that below this tuning frequency subs tend to unload meaning the sub is effectivly playing free air, which can damage it if its not designed to do that.

 

Bandpass boxs take serious skill to get right.

 

have a look at this page http://members.lycos.co.uk/efmax/boxdes ... lained.htm

 

The guy has serious skill, and can come up with the most amazing boxes.

[Pete 0]

Ckid:

 

The theory is that the different panel thickness reduces vibrations even further.

 

Not too sure about the science behind it though... :oops:

 

I have Mark Levinson Home hifi which uses this and its a real audiophile trick.

[corradokid 0]

Pete, will have a look into this as its always nice to read about new ( to me anyway ) ideas. Do you have any links?

[Pete 0]

http://www.marklevinson.com

 

No mention of the construction though [and please don't look up the prices while standing up...]

 

Wadia do a similar chassis. Its called MONOLITHIC construction. Not much mentioned on the website though.

 

http://www.wadia.com/technology/tech_guide.htm#CC