Can these cabinets be made to work without the need for dampening material? The .5" Bamboo ply is supposedly 25% harder than Oak. My current speakers are the Blumenstein Orca's which are also designed to work without the need for any dampening material. I like the minimalist philosophy used in these little speakers and hope to replicate it on a larger scale with the Alpair 12P.
The Pensil for 12P is a much bigger box than the Orcas, and the 12P can move substantially more air at much lower frequencies than an FE83E, so AFAIC, some minimal panel bracing should be considered mandatory.
And as with all MLTLs, a certain amount of damping is part of the design calculus, but you will find anecdotal evidence from a range of builders of the Pensil family that final actual amounts can vary.
If you mean birch or bamboo plywood, I'd strongly recommend at least 15mm BB for the enclosures, and as Jeff notes the 12P's mounting flange is thick enough to require a minimum of 24mm depth in at least the immediate driver area to allow for rebating driver for flush mounting - which also should not be considered optional.
And as with all MLTLs, a certain amount of damping is part of the design calculus, but you will find anecdotal evidence from a range of builders of the Pensil family that final actual amounts can vary.
If you mean birch or bamboo plywood, I'd strongly recommend at least 15mm BB for the enclosures, and as Jeff notes the 12P's mounting flange is thick enough to require a minimum of 24mm depth in at least the immediate driver area to allow for rebating driver for flush mounting - which also should not be considered optional.
No, damping is an integral part to the proper functionality of the design: the pensils are not bass reflex speakers, they're transmission lines. The damping is intended to be easily adjustable to preferences, but these enclosures are designed to use a reasonable amount in order to provide a relatively unreactive impedance load approaching that of a classical TL.
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While they're both MLTLs Bob and I had rather different alignments and different design objects for the two enclosures, so comparisons are somewhat apples / oranges. Speaking under correction, I suspect Bob has tuned lower & aimed for the lowest practical quantity of damping. The pensils are tuned a little higher for a pro-audio style alignment & use near TL levels of damping to provide the flattest practical impedance load. Name your poison.
Fruit? personally I'm more of an orange guy, but which is which?
Having followed the evolution of Bob's designs and construction methods for a few years now, and having built one of his enclosures ( M1-A10), and many more of Scott's, I can definitely confirm that while they may use similar design tools ( MJK worksheets) their performance targets and construction approaches are quite different.
Both are equally valid.
Having followed the evolution of Bob's designs and construction methods for a few years now, and having built one of his enclosures ( M1-A10), and many more of Scott's, I can definitely confirm that while they may use similar design tools ( MJK worksheets) their performance targets and construction approaches are quite different.
Both are equally valid.
I design my MLTL's to get to 40Hz in room. I presume room lift and I try to keep the cabinet somewhat overdamped. My speakers are designed around acoustic instruments and solo vocalists. As such the MLTL's for the A10's and A12's have good solid bass, but not overwhelmingly so. If I read things right, Scott's Pensil's don't go as low and have a wide bump up below 100Hz. This gives them a puncher sound, but less real bass. When I build my first M10-A10 with the A12.2, I also built a pair of the comparable Pensil's and I found this to be true. So....
If you are into modern music where kick drum is the predominant bass, go with the Pensil's. If you are into acoustic music, go with mine. And yes, this is a biased opinion.
Bob
If you are into modern music where kick drum is the predominant bass, go with the Pensil's. If you are into acoustic music, go with mine. And yes, this is a biased opinion.
Bob
And now, for another biased opinion 
- as noted in another thread, I spent several hours just yesterday afternoon listening to among other things Alpair12Ps in a pair of SuperPensils. While I haven't heard Bob's MLTL for this driver, or for that matter directly compared the M10A10 and Pensils for the 10.2 or 10.3 (the latter two being different enclosures) I 'm pretty confident the SPs go well below 40Hz in room - yes they may be a bit warm/fat in the lower mid bass, but not likely something that playing with stuffing and amplifier choices couldn't mitigate. Of course I don't have any in room measures to prove that.
- as noted in another thread, I spent several hours just yesterday afternoon listening to among other things Alpair12Ps in a pair of SuperPensils. While I haven't heard Bob's MLTL for this driver, or for that matter directly compared the M10A10 and Pensils for the 10.2 or 10.3 (the latter two being different enclosures) I 'm pretty confident the SPs go well below 40Hz in room - yes they may be a bit warm/fat in the lower mid bass, but not likely something that playing with stuffing and amplifier choices couldn't mitigate. Of course I don't have any in room measures to prove that.
Pretty much Bob. For the sake of interest, this is the stock pensil alignment with the default damping levels; the target is broadband gain with the ~60Hz - 150Hz region where the majority of LF energy resides tickled up slightly to give a little extra slam factor (these things being relative), & as flat an impedance load as possible without going to a 'pure' TL. In practice they usually do a decent open E double bass, although the end results of course depend on what damping levels people prefer to use in their boxes.
The so-called superpensil (or the current one at any rate) has broadly similar characteristics except it's got another 10Hz LF extension, although it was intended for higher output impedance amplifiers to achieve the target response.
I should note that this is not the only MLTL alignment I use. It just happens to be one of my favourites.
The so-called superpensil (or the current one at any rate) has broadly similar characteristics except it's got another 10Hz LF extension, although it was intended for higher output impedance amplifiers to achieve the target response.
I should note that this is not the only MLTL alignment I use.
It just happens to be one of my favourites.Attachments
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No doubt. Alas, I don't have a pair here at present (if I had a pair of every speaker I designed over the years, they'd probably stretch, laid end to end, from here to Aberdeen), nor do I have any measuring equipment at the moment either unfortunately What I had was sacrificed into the open maw of my PhD a while back. In fact, the only system I currently have in permanent use is a pair of Dave's (excellent) uFonkens on my desktop as computer monitors powered by a little Scythe class D amp.
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I think there not much difference between the a10 and a12. Everyone who have heard both driver like both. I think you cant go wrong with either. The difference is in the metal vs paper. I have strong belief about not buying anything but paper cones.Hello Friends,
I am trying to decide between Alpair 10P and 12P. What I am looking from these drivers is a realistic reproduction of male voices like Nat King Cole. I am not sure which way to go. Any experiences to share?
Also I have to choose between MLTL and Pensils
murphy - if you're talking about the current 10s - paper and metal and 12P, I'd beg to differ about "there (being) not much difference" - in approximately equivalent boxes, I found the 12p went much deeper and had greater dynamic impact, particularly on drums, plucked double bass etc, while the 10P was more extended on the top end
as for the current A10.3M and 12P - no contest about the bottom end or sensitivity, but the metal is far more extended on the top end than the 12P, subjectively even more presence than the 10P in my few sessions
which is any of the 3 is "better"?
not touching that one -
but if forced to pick just one to replace my current 7s - it'd probably be the 10P in either the FHXL or Pensil
so, I guess I did "touch this" - HammerTime!
as for the current A10.3M and 12P - no contest about the bottom end or sensitivity, but the metal is far more extended on the top end than the 12P, subjectively even more presence than the 10P in my few sessions
which is any of the 3 is "better"?
not touching that one
-but if forced to pick just one to replace my current 7s - it'd probably be the 10P in either the FHXL or Pensil
so, I guess I did "touch this" - HammerTime!
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I'm a sucker for the sound of male vocals on the 10Ps - Kevin Mahogany, Terry Evans, Jamie Cullum, Jim Byrnes, Buddy Guy, Muddy Waters, SwingSoniq - but that's just me. I tend to favor the slightly brighter / "open" top end for what it does for female vocalists such as Alison, Diana, Ella, Eva, Holly, Jacqui, k.d., Madeline, Patricia, the Jennys - and a couple of those gals can play the piano too
Diana's "All for You" is a must have for Nat fans, Patricia Barber can play just about anything, and Holly Coles' "Temptation" (1995) is a treat for Tom Waits aficionados. I digress as usual
Kits for Pensils for either driver wouldn't be that difficult a cutting job, but the dimensions are such that once packaged shipping rates can get out of hand fairly quick.
when you say more extended on top, what do you mean? You can hear more clearly the highs, or the extended simply higher in the 15khz zone?murphy - if you're talking about the current 10s - paper and metal and 12P, I'd beg to differ about "there (being) not much difference" - in approximately equivalent boxes, I found the 12p went much deeper and had greater dynamic impact, particularly on drums, plucked double bass etc, while the 10P was more extended on the top end
as for the current A10.3M and 12P - no contest about the bottom end or sensitivity, but the metal is far more extended on the top end than the 12P, subjectively even more presence than the 10P in my few sessions
which is any of the 3 is "better"?
not touching that one
but if forced to pick just one to replace my current 7s - it'd probably be the 10P in either the FHXL or Pensil
so, I guess I did "touch this" - HammerTime!
murph - I'm somewhat of an agnostic re the primacy of measurements over subjective listening and it's hard to look at the the FR graphs for the two drivers and proclaim that what I hear is clearly there on paper.
Perhaps it's the slightly steeper peak trough peak that shows up on the 10P around 5K vs the wider and shallower valley between around 3K and 8K on the 12s that I hear as more upper mid-range presence in the 10s? Indeed, looking at the RAW data published on Mark's site, the 12 seems to have a slight advantage in the 15-20K range before they both start to fall
I don't honestly know why, but to your words, I guess I hear more clearly the highs (more precisely from the upper midrange 5-6K up ?) on the 10Ps.
Of course my daily drivers are still the 7s, which are certainly not shy in the 9-12K range, and certainly extend further than either of the large papers - so perhaps I'm more atuned to that section of the spectrum?
geeze, now you've got me second guessing myself - which is not always a bad thing - sooner or later, I'll be right about something
Perhaps it's the slightly steeper peak trough peak that shows up on the 10P around 5K vs the wider and shallower valley between around 3K and 8K on the 12s that I hear as more upper mid-range presence in the 10s? Indeed, looking at the RAW data published on Mark's site, the 12 seems to have a slight advantage in the 15-20K range before they both start to fall
I don't honestly know why, but to your words, I guess I hear more clearly the highs (more precisely from the upper midrange 5-6K up ?) on the 10Ps.
Of course my daily drivers are still the 7s, which are certainly not shy in the 9-12K range, and certainly extend further than either of the large papers - so perhaps I'm more atuned to that section of the spectrum?
geeze, now you've got me second guessing myself - which is not always a bad thing - sooner or later, I'll be right about something
I personnaly use a 3 db boost at 6khz and then 11khz, so I raise the whole 5khz to 12khz region up 3 db. It greatly helps with the issues you mentioned.
Without the help of eq, I personnaly felt the highs a bit lacking, but that may be personal taste? I really appreciate hearing clearly the hi hats with jazz so....
Without the help of eq, I personnaly felt the highs a bit lacking, but that may be personal taste? I really appreciate hearing clearly the hi hats with jazz so....
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