Ways to lower tuning?

[groundpound4200 5,000+ posts]

some bad info ITT...

 

[Moble Enclosurs 10+ year member]

If he were to add mass inside the enclosure to lower the compression area, while maintaining the same port area, wouldnt this lower box tuning?

Only if the added mass were to slow down the sound waves. Adding mass with equal or more density than the enclosure material, would actually increase tuning.

 

[Moble Enclosurs 10+ year member]

I thought it was opposite...lowers tuning

No. Increasing acoustical compression increases tuning, if all other variables were equal.

 

[24v 10+ year member]

*WARNING Stupid Newb Question*

Couldn't he add some polyfill to get the desired effect? It is my understanding that adding polyfill is similar to a displacement increase. Increased displacement would lower tuning, right?

 

[Moble Enclosurs 10+ year member]

*WARNING Stupid Newb Question*Couldn't he add some polyfill to get the desired effect? It is my understanding that adding polyfill is similar to a displacement increase. Increased displacement would lower tuning, right?

In essence, yes, but this has a different effect on the overall sound than a properly constructed design without it. Normally, polyfill is more desired in a sealed enclosure for tuning purposes, or transmission line enclosures for LF output at the opening while dampening the HF from the rear wave for proper reproduction. In subwoofer designs other than sealed, which is based mainly on the Q factor, is not necessary for tuning. It will also, likely not do much to the tuning if the desire is to lower it by many frequencies, rather than a few(1-6Hz band).

Best bet is to properly construct a compression area and port volume for the desired frequency range, rather than tuning frequency, as the tuning frequency has minimal relationship to the entire response, unless the desired goal is SPL output alone.

I will not say do not do it though. Most of what we know today is based on trial and error.

 

[Moble Enclosurs 10+ year member]

*WARNING Stupid Newb Question*Couldn't he add some polyfill to get the desired effect? It is my understanding that adding polyfill is similar to a displacement increase. Increased displacement would lower tuning, right?

Think of designing enclosures this way in the idea stated in the quote:

For tuning a vehicle for speed, would you rather use a mod chip to trick the vehicle into a couple of extra horsepower, or would you rather get the turbo and hook it up correctly to get much more than a few horsepower?

 

[hispls 5,000+ posts]

*WARNING Stupid Newb Question*Couldn't he add some polyfill to get the desired effect? It is my understanding that adding polyfill is similar to a displacement increase. Increased displacement would lower tuning, right?

May work somewhat. There is some good data out there if you google the subject of stuffing boxes with polyfill. The biggest issue with stuffing a ported box in this type of scenario is stuffing firing out a big *** port into your trunk... I've tried it and it's a mess (It did change the boxes response a bit though)