enclosure/sub woofer question

good post steve, I agree.

Also Ranger has posted some great examples....

 

Thanks VIKING, check you're pm. I'm going get another beer

 

Please show me where you get that information from so that I may look it up.
My information comes from
V Dickason, "The Loudspeaker Design Cookbook" Audio Amatuer Press, 10/91.

If my MLA citation is not correct please PM me

I don't consider myself an expert on box design. With that said I've built around 500 to 600 boxes and I have never seen one case where the failure of one sub caused a failure in another, not once.

Also, the port tuning has to do with the size of the enclosure, not the woofer or the number of woofers. So if a woofer blows in a multiple woofer format, the tuning will remain unchanged.

The standard equation used for tuning does not reference any woofer specs.

r= radius of the port
Vb = box volume
Fb = is the desired tuning of the enclosure
Lv = vent length

 

Two other sources if your interested

R. Small, "Vented Box Loudspeaker Systems" JAES, June through October 1973

R. Bullock III, "Thiele, Small, and Vented Loudspeaker Design" Speaker Builder 3/81

 

You are right and I agree with you 100%.

We need to be realistic and we need to build to fit our vehicle. My Mercury has a single 12-inch woofer in a 1.85 cu ft box tuned to 42Hz. It will play any music I want to with no problem and it will play "low".

It would provide perfect performance in your car if you go with a 1.8 to 2 cu ft box and tune it between 38 to 40 Hz. The performance will be great.

 

I recall many audio books,and don't recall anything contradictory of what I've said.Well,I have seen them blow more than once,but always at high power. Cannot say how many boxes i've built(don't remember) nor can i say how many systems i have designed after all these years.

You are indeed correct in that box tuning has nothing to do with the spkr specs.However the box design and tuning have everything to do with how the spkr reacts, that being said..if one sub were to fail or become disconnected, the other sub would suddenly be under greater mechanical stress, and possibly fail....Why? well simply put(we design enclosers for spkrs,right?) the spkr will reach Xmax sooner(greater mechanical stress) the excesive cone movement can also result in thermal failure in the vc...Why? Because the active driver will see over 2X of the space backpressure will cause the (blown) woofer to move out of phase,some T/S parameters are altered,the blown sub tries to act as a p/r , the subs power handling is lowered....bottom line is that in general using 2 subs in a shared box will have more chance of going out than using multiple subs is the point I was trying to make. Of course i wouldn't be too worried of this if power was not very high in a large box with only 2 subs.

 

And I do agree with that statement. Thank you for Clarifying.

 

different ideas, different thoughts......different ideas and lots of theory. If it was not for the thought process involved in all of this, we all would be buying wal mart boxes and thinking they sound great. it is always good to question those that have other opinions and ideas that do not agree with our own reason. the perception of ideas may vary intensly, but the end result may be the same.



I love this site! so nice to see adult converastion and no flaming BS. Outstanding folks!

 

I agree. i'm so glad i finally found a site with adults who use some logic in their responses and can see/debate others views without being condescending or rude about it.
Sounddomain forums were the worst imo, after a couple others i finally landed here and has been good reading ^_^

 

dont wanna steer this thread off course.....but typically all comments and suggestions are done in an adult manner.....we like it that way, as do other users in this great site. We wont deal with excessive conflict aimed at others for differing opinions.

Now....back to the program! LOL!