Which Pensil plan?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
There is a shallower version of the Pensil12P, but I believe the way the math works for MLTLs, the line length and driver placement shouldn't be changed.

FWIW, if you don't already own the 12P, the 10.3 or 10P can probably go lower in a much smaller box- such as the appropriately tuned Pensil, or the FHXL - at the sacrifice of a bit of sensitivity - and unless running a single digit watt SET amp, I'd frankly consider that almost irrelevant.

Time for Jeff to pipe in any time now...,;)
 
Well, as you know I love the 10p+FHXL and the 12p Super Pensils. I think I could live with either long term, but I never felt I could push the 10p drivers as hard as I do the 12p's. So if playing rock music loud is something that the speakers will have to do occasionally, then the Super Pensils might be the way to go. They will certainly play Steely Dan just fine.

Hard to give without knowing room size, amps to be used etc.

jeff
 
Thank you clarifying this for me.
The 37" is the correct plans for the 12P. (12.2)
My room is 14" x 25 (It is in the basement, carpeted, with 7' ceilings) and I must sit 12' away from the front wall that is 14' due to a support Column.
I will be running them with a KR Audio VA300 amp - that puts out around 12 watts.
Thanks
Mike
 

GM

Member
Joined 2003
There is a shallower version of the Pensil12P, but I believe the way the math works for MLTLs, the line length and driver placement shouldn't be changed.

FWIW, AFAIK it ideally depends on both the line length and CSA, but it only theoretically reduces the amount of internal damping required for a given Qt and never having actually tested it, I don't know if the difference would be even perceived, much less audible, so in the scheme of things a plenty good enough 'rule of thumb' is to have them at the line's odd harmonics and though they aren't acoustically exactly at these locations, dividing by 3, 5 works just fine and of course the 1st harmonic is the fundamental, so is at the extreme ends, ergo has the most pipe gain and consequently typically requires the most damping if used wide range.

Scott chose a good compromise for the driver's specs by placing it at the first 5th and the vent at the bottom 1st. If the driver spec'd a larger net Vb, then it could have been made taller and the driver dropped to a 3rd or second 5th and still been at a good seated ear height without penalty, but most folk's desire for tiny cabs severely limits the aspect ratio if minimal damping and a smooth response is desired.

FWIW, some years ago I noted that these drivers tend to be just right for the taller cabs while still maintaining the same CSA as one when used in pairs [2x Vas], so for those folks that want more LF for BSC/whatever and can tolerate a taller cab and extra parts cost, making 1.5 systems using the same driver model allows one to 'have their cake and eat it too' WRT the sonic perks a 'single driver' system offers.

Speaking of which, has anyone [been] 'campaigning' for some tonally matching wide range drivers designed specifically for 1.5 alignments? Seems like they could be made somewhat less expensive to keep parts costs down, yet increase a manufacturer's 'bottom line', a 'win-win' for everyone.

GM
 
GM,

Greetings!

Thank you for the insightful post.

Regarding a taller cabinet for 2 drivers in 1.5 config, does overall cabinet volume need to be 2x vs single driver cabinet? If that is the case and CSA is same as before, then basically double the height of the cab? I am probably wrong here... would appreciate yours inputs.

Thanks in advance.
 
Greets!

Hmm, in retrospect, that's what I seem to be implying, though not quite what I meant as while 2x height will work, it will still suffer from strong TL pipe modes and be stronger due to having a lower fundamental, so potentially requiring not just proportionately more damping, but even more dense to boot.

Instead, just increase the pipe based on one of the 'optimum' driver locations from the top relative to seated ear height to a minimum increase of ~1.42x. Obviously, the response will probably change some, so vent tuning may need to be adjusted lower, though in room, not necessarily and IME they just sound better overall due to better driver control with the same [or less] damping as for the shorter, single driver alignment.

GM
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.