Parallel 6th for team fi 18

[rocking.that.eclipse]

19 hours ago, Triticum Agricolam said:

Ratios don't really apply to parallel-tuned 6th order boxes.  Also the high side is almost always significantly smaller than the low side, its generally the opposite for series-tuned boxes.  

I'm surprised i would have assumed that you would want a higher ratio. I see the highs side not mattering as much to space since lows side is controlling the cone

 

[WalledSonic]

I wonder what happens if these rules are followed when using designing software for a parallel tuned 6th, as Mr. Bose described in his patent:

"It has been discovered that best results are obtained when the ratio of volumes of the two subchambers is within the range 2:1 and 4:1, with the ratio of the corresponding port resonances in a ratio within the range between 1.5:1 and 3.0:1"

The thing is, at the time of his patent 30 years ago, there weren't many people designing enclosures like this yet and software hadnt been developed.  I wonder how in the last 30 years since the patent was issued how the 'rules' may have changed for this enclosure style.

Source: https://www.google.com/patents/US4549631

[Ernest]

Here is something that just dawned on me, I'm not sure if I can do this but it would be a huge space saver with this 6th order dream I have lol. I have 2 18" psi passive radiators, would it work if I use them on the low chamber Tuned to 28hz and on the high's chamber use a standered slot port? Have any one ever done this? Or would the pr's cause problems with the highs port. Would all you guys laugh at me for doing it ?

[Triticum Agricolam]

2 hours ago, Ernest said:

Here is something that just dawned on me, I'm not sure if I can do this but it would be a huge space saver with this 6th order dream I have lol. I have 2 18" psi passive radiators, would it work if I use them on the low chamber Tuned to 28hz and on the high's chamber use a standered slot port? Have any one ever done this? Or would the pr's cause problems with the highs port. Would all you guys laugh at me for doing it

That should work just fine.  I haven't seen it done in the caraudio world yet but bandpass boxes using PRs has certainly been done.  I don't think you will have any problems as long as you have enough capacity in your PRs. 

[Triticum Agricolam]

4 hours ago, rocking.that.eclipse said:

I'm surprised i would have assumed that you would want a higher ratio. I see the highs side not mattering as much to space since lows side is controlling the cone

 

Both chambers will control cone excursion when playing around their respective tuning frequencies. You are right that you don't really need to limit excursion around the higher frequencies though, so high chamber size isn't important in that regard.  The problem you will run into with too large of a high chamber is you will get too much of a boost in those higher frequencies and it will sound like the box is lacking lows.  It also puts a lot of stress on the cone.