You?re welcome!Originally Posted by Encyclopediabsh
OK???..
Again, it depends on the system?s output impedance [total series resistance the driver[s] ?feel?], the amount of room/boundary gain and desired LF response. GPA is a manufacturer that must CYA itself against product liability, so it?s in their best interest to suggest an alignment that pretty much protects the driver against over excursion damage at rated power. They may also believe this is an optimum alignment for all I know, but from long experience it sure isn?t my idea of one except when the other considerations dictate it.
Again, my attitude when there?s not enough measured data to make a well informed choice is to recommend the largest acceptable cab since it has the most tuning flexibility, i.e. it?s a lot easier to ?shrink? a cab than it is to ?stretch? it if the bass line sounds unacceptably ?lean?.
Based on published specs, your acoustically relatively large room and high [unknown] output impedance amp, a reasonable worst case would be a ~23.3 ft^3 net cab tuned to Fs if a matching impedance and due to true half space [2pi] loading, it can be reduced to its Vas rating or ~11.65 ft^3 net without any obvious loss of LF acoustic efficiency down to ~25 Hz in a sim.
If you built them full size, they would probably sound too ?boomy? and have problems with TT ?rumble? if spinning vinyl, so they would need to be empirically damped to deal with this. For my personal use, this is the way I would go since it?s the best size overall for a sealed alignment if desired, but I tend to prefer a much ?tighter? [damped] compression horn-like presentation than most folks, so quit recommending it once I found out folks were mis-tuning and/or reducing cab net Vb to get the [vintage] ?tone? that sounded best to them.
In short then: ~9.0-23.3 ft^3 net/tuned to measured Fs, your call.
Make it the max height and post new internal [i.d.] dims once a net Vb is chosen for more design details.
GM
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