Hmm, based on this thread and its associated article, measured specs, any number of alignments could be used, so it's more about what size, tuning you want:
http://www.diyaudio.com/forums/full-range/142599-markaudios-alpair-10-german-test-review.html
https://www.hifi-selbstbau.de/index.php?option=com_content&view=article&id=275&Itemid=91
Resonant frequency Fs
DC resistance Rdc
Mechanical QMS
Electrical Q Qes
Total Qts
Effective moving mass Mms
equiv. Air volume Vas
power factor BL
efficiency Eta (1m, 2.83V, half space)
39.69 Hz (+/- 0.6%)
5:46 ohms (+/- 0.3%)
2,340 (+/- 1.4%)
0.353 (+/- 1.0%)
0.307 (+/- 1.2%)
8.84 gr (+/- 1.7% )
20.85 dm³ (+/- 0.5%)
5.84 N / A (+/- 1.2%)
89.25 dB (+/- 00:07)
GM
http://www.diyaudio.com/forums/full-range/142599-markaudios-alpair-10-german-test-review.html
https://www.hifi-selbstbau.de/index.php?option=com_content&view=article&id=275&Itemid=91
Resonant frequency Fs
DC resistance Rdc
Mechanical QMS
Electrical Q Qes
Total Qts
Effective moving mass Mms
equiv. Air volume Vas
power factor BL
efficiency Eta (1m, 2.83V, half space)
39.69 Hz (+/- 0.6%)
5:46 ohms (+/- 0.3%)
2,340 (+/- 1.4%)
0.353 (+/- 1.0%)
0.307 (+/- 1.2%)
8.84 gr (+/- 1.7% )
20.85 dm³ (+/- 0.5%)
5.84 N / A (+/- 1.2%)
89.25 dB (+/- 00:07)
GM
One easy way to find Alpair 10 enclosure references is to search this forum. I designed several 'Alpair 10 MLTL' designs so try that search for references to my (and others) efforts. I also have an open back Alpair 10 design in that search. I've done Alpair 10 MLTL designs that work for Alpair 10 and 10.2 (the same design is tolerant to either) another design for a 10.3 MLTL version.
Around 2009-2010, I built for my Alpair 10 Gen 1 a box presented as MLTL (I drew inspiration from one of Jim's publications, if I remember correctly).
Back in those days, there were already also classical bass-reflex enclosures, things called "pencils", backloaded horns etc etc.
When I look at the enclosures published nowadays for Gen 3, I see not much variation, some have increased the volume of what looks basically like a BR enclosure with the shape of a thin column, but they claim that the classical load (lesser volume, as back in 2009) is more pleasing on their favorite music etc etc. From what I(ve read so far, there are frequent claims that the 10.3 is fundamentally different from the previous versions.
So: much ado for nothing ? Maybe.
Fact is, I don't personally see a major difference in the TS parameters between 10.1 and 10.3 (Fs in the region of 36-39 hz, Qts in the region of 0,32 - 0,33...). Here is what seems to be the datasheet of 10.1: https://www.hifi-selbstbau.de/images/stories/chassis/markaudio_MA10G/Markaudio_Alpair10.pdf
To me, it seems that any load that worked for 10.1 also works for the 10.3 and vice versa. A variation of 1 or 2 cm on the diameter or length of a vent does not say much.
As far as I know, in the speaker world, there are usually even (much) greater variations connected with manufacturing tolerances for a given model of a speaker.
What is unclear to me, on the other hand, is whether people still use a small serial LR equalizing. With the Gen 1, I remember that the vast majority of users implemented such a small equalizing circuit to compensate the baffle step effect due to the narrow front panel. With the current Alpair 10.3, most front panels are still narrow (in the 8"-9" region) but I've not seen - so far in my readings - someone using an LR compensation. I'm inclined to think that if there has been a major evolution, then it is probably in the overall balance of the FR.
Back in those days, there were already also classical bass-reflex enclosures, things called "pencils", backloaded horns etc etc.
When I look at the enclosures published nowadays for Gen 3, I see not much variation, some have increased the volume of what looks basically like a BR enclosure with the shape of a thin column, but they claim that the classical load (lesser volume, as back in 2009) is more pleasing on their favorite music etc etc. From what I(ve read so far, there are frequent claims that the 10.3 is fundamentally different from the previous versions.
So: much ado for nothing ? Maybe.
Fact is, I don't personally see a major difference in the TS parameters between 10.1 and 10.3 (Fs in the region of 36-39 hz, Qts in the region of 0,32 - 0,33...). Here is what seems to be the datasheet of 10.1: https://www.hifi-selbstbau.de/images/stories/chassis/markaudio_MA10G/Markaudio_Alpair10.pdf
To me, it seems that any load that worked for 10.1 also works for the 10.3 and vice versa. A variation of 1 or 2 cm on the diameter or length of a vent does not say much.
As far as I know, in the speaker world, there are usually even (much) greater variations connected with manufacturing tolerances for a given model of a speaker.
What is unclear to me, on the other hand, is whether people still use a small serial LR equalizing. With the Gen 1, I remember that the vast majority of users implemented such a small equalizing circuit to compensate the baffle step effect due to the narrow front panel. With the current Alpair 10.3, most front panels are still narrow (in the 8"-9" region) but I've not seen - so far in my readings - someone using an LR compensation. I'm inclined to think that if there has been a major evolution, then it is probably in the overall balance of the FR.
Without proofing your driver comparison; at least your reasoning, assumptions are spot on since other than the baffle's impact on the corner frequency between 2-4 pi space and ignoring horn design, the cab's loading on a driver peters out at ~2*Fs/Qts [HF mass corner/fhm] and since this is normally below our acute hearing BW, the cab merely acts as an IB above this point since the cab is now acoustically large for the BW and the driver is now in its mass controlled BW.
WRT to spec tolerances, down low we rely mostly on [usually quite high] distortion levels to tell any difference in tunings, etc., and even then many folks perceive its higher harmonics that comb filter with the driver's output quite euphonic as proven by the popularity of the multiple long vent Onkens/Jensens that in some cases can be audible above its fhm.
GM
WRT to spec tolerances, down low we rely mostly on [usually quite high] distortion levels to tell any difference in tunings, etc., and even then many folks perceive its higher harmonics that comb filter with the driver's output quite euphonic as proven by the popularity of the multiple long vent Onkens/Jensens that in some cases can be audible above its fhm.
GM
Hi Dave,
Since you're around: do you use some equalizing crossover in your various implementations with the Gen3 (or Gen 2) ?
And just in case someone has an early pair of Gen 1 (Gold) laying around, let me know. I am pleased by the results of my "old" 10.1 in 30 liter MLTL (+2,2 mH//3,3 ohm) but would want to try two drivers in parallel per channel in a 60 liter MLTL...
Since you're around: do you use some equalizing crossover in your various implementations with the Gen3 (or Gen 2) ?
And just in case someone has an early pair of Gen 1 (Gold) laying around, let me know. I am pleased by the results of my "old" 10.1 in 30 liter MLTL (+2,2 mH//3,3 ohm) but would want to try two drivers in parallel per channel in a 60 liter MLTL...
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