Hi ilwooz, aha, okay you are looking to build something very specific, as opposed to the theory.
MJK's classic TL alignment tables don't cover MLTL (which can be tuned lower than a classic TL for a given rough cabinet size). Classic TL means no port tube, MLTL has the port tube (which is the ML or mass loading in MLTL).
So you might want to post questions here and one of the gurus will have excellent suggestions or will run a calculation in a tool such as Henkjan has suggested. GM can do this stuff in his head, by the way.
MJK's classic TL alignment tables don't cover MLTL (which can be tuned lower than a classic TL for a given rough cabinet size). Classic TL means no port tube, MLTL has the port tube (which is the ML or mass loading in MLTL).
So you might want to post questions here and one of the gurus will have excellent suggestions or will run a calculation in a tool such as Henkjan has suggested. GM can do this stuff in his head, by the way.
I really don't think it's worth doing an Alpair VTL. The Creative Sound version is wider and deeper than the JX92 VTL, so they have clearly adjusted the line cross-section and/or increased the cavity volume. But they have already taken Ted's VTL and used it for other drivers so they have some experience with the design.
Given that Jim Griffin has already designed an MLTL, that would be the one I would go for. The triangular MLTLs do look attractive and their shape means they can go back against a wall and require no additional toe-in.
You could build it square and adjust the width vs depth to match that of the VTL, although you'd have rather a monolithic slab at the end of it. A Russian chap did a curved version of this for the JX92 48" MLTL somewhere on this forum.
Or go for the JX92 VTL, which is a proven design with some nice reviews of the commercial versions (see the HiFi News review on the MJ Acoustics site, below).
Just my thoughts. Others here will have a better idea how to approach the design of a genuine ALpair 10 VTL-style cabinet.
MJ Acoustics S1R
Given that Jim Griffin has already designed an MLTL, that would be the one I would go for. The triangular MLTLs do look attractive and their shape means they can go back against a wall and require no additional toe-in.
You could build it square and adjust the width vs depth to match that of the VTL, although you'd have rather a monolithic slab at the end of it. A Russian chap did a curved version of this for the JX92 48" MLTL somewhere on this forum.
Or go for the JX92 VTL, which is a proven design with some nice reviews of the commercial versions (see the HiFi News review on the MJ Acoustics site, below).
Just my thoughts. Others here will have a better idea how to approach the design of a genuine ALpair 10 VTL-style cabinet.
MJ Acoustics S1R
Colin said:
Just build the VTL cabinet. The A10 should work in it -- at least as well as the VTL works.
I am suspicious of the VTL cabinet, it shows no signs of anything but classic TL design and sims show expected problems with ripple.
One could fairly easily fold the GM 48" ML-TL into a VTL-like profile, Or if one was going to use the Alpair 10 start with the Griffin ML-TL
dave
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Hi guys,
thanks to everybody for the replies. Actually my choice would be the Alpair 10 over the Jordan, mainly for the more accurate parameters responses compared to those stated by the manufacturer. Since I am a newbie and I have no the instruments and knowledge to do the measurements and the adjustments to solve eventual problems when the build is done, I think the Alpair should be a safer way for me. I saw the MLTL for the Alpair 10 done by Jim Griffin and for sure is an excellent design, I would try to build my speakers following this project but the cabinet is a bit too tall. This is the reason why I'm looking for a way (if exists) to adapt the aspect of one of the original MLTL 48" designs (GM's for the JX92S or JG's for the A10) to the Jordan's VTL (as I said, I like the aesthetics of the Konus Essence very much, it remainds me at the monolith of Kubrick's 2001 – sorry for this "crazy" OT). The GM 31" is of course a very good alternative but, assuming to choose the Alpair 10, once again is not clear in my mind what I have to do to modify this design to fit the A10 parameters (and, eventually, to make it looks like the Konus Essence). Summarizing, the goal would be to build a pair of towers with the Alpair 10 in a MLTL less tall and more wide, with a frequency response extended and linear like the GM's 48" or the JG's 47" for the A10. However, a GM's MLTL 31" adapted to the Alpair 10 parameters would be a pleasant alternative.
Daydreaming?
Thank you so much guys and bye,
Christian
P.S. Dave, the frequency response graph you posted is very eloquent, thanks a lot...
thanks to everybody for the replies. Actually my choice would be the Alpair 10 over the Jordan, mainly for the more accurate parameters responses compared to those stated by the manufacturer. Since I am a newbie and I have no the instruments and knowledge to do the measurements and the adjustments to solve eventual problems when the build is done, I think the Alpair should be a safer way for me. I saw the MLTL for the Alpair 10 done by Jim Griffin and for sure is an excellent design, I would try to build my speakers following this project but the cabinet is a bit too tall. This is the reason why I'm looking for a way (if exists) to adapt the aspect of one of the original MLTL 48" designs (GM's for the JX92S or JG's for the A10) to the Jordan's VTL (as I said, I like the aesthetics of the Konus Essence very much, it remainds me at the monolith of Kubrick's 2001 – sorry for this "crazy" OT). The GM 31" is of course a very good alternative but, assuming to choose the Alpair 10, once again is not clear in my mind what I have to do to modify this design to fit the A10 parameters (and, eventually, to make it looks like the Konus Essence). Summarizing, the goal would be to build a pair of towers with the Alpair 10 in a MLTL less tall and more wide, with a frequency response extended and linear like the GM's 48" or the JG's 47" for the A10. However, a GM's MLTL 31" adapted to the Alpair 10 parameters would be a pleasant alternative.
Daydreaming?
Thank you so much guys and bye,
Christian
P.S. Dave, the frequency response graph you posted is very eloquent, thanks a lot...
Hi BP,
If you're looking for a "Rock Un Roll" driver, the Alpair 10 will have its limitations. Can you give more information as exactly what you're trying to achieve? What amplification you're using? etc etc. The new gen 2 drivers are wide dispersion. Typically 7 to 12 degrees will illicit a near flat wide response.
This link to the new Gen. 2 Alpair 10 maybe useful.
http://www.diyaudio.com/forums/markaudio/158417-alpair-10-generation-2-sneak-peek.html
Cheers
Mark.
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Hi Mark, I have two enclosure designs in mind- one is a stand mounted design utilising 2 unts in each enclosure, reflex. The enclosure will be an injection moulded type.
The 2nd design is just an experimental horn type
I've been a fan of metal drivers for a while- As well as sound quality and looks, SPLs and the way the drivers behave at the low end are important- these two look to be the best full rangers within my budget.
Couple of further questions- is there a real benefit to adding a ribbon tweeter? And if the Jordans have to be toed in so much, how would this affect the tweeter axis?
The 2nd design is just an experimental horn type
I've been a fan of metal drivers for a while- As well as sound quality and looks, SPLs and the way the drivers behave at the low end are important- these two look to be the best full rangers within my budget.
Couple of further questions- is there a real benefit to adding a ribbon tweeter? And if the Jordans have to be toed in so much, how would this affect the tweeter axis?
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Hi BP
I'm tempted to suggest going for the stand-mount design using 2 drivers on the basis that you're looking to go louder. At least if you turn the volume up, the higher loads are spread between 2 drivers. Spacing the drivers is important. Best to keep them close together. I'm assuming you've got the amp muscle to power 2 drivers.
Re your 2 questions. It wouldn't be right for me to comment on adding a ribbon tweeter to a Jordan given that I'm in competition with this maker.
Regarding adding a tweeter to FR's generally, your correct in thinking there may be directional issues when mixing some drivers.
As a general guide, you're on safer ground when mixing drivers if the FR's off-axis response is more efficient at maintaining a consistent output when placed off axis. Take a look at the off-axis tests recently published in Japan's MJ audio magazine. Note the differences between Diatone's P-610 driver and the Alpair 12. The Alp is maintaining much of its output above 10-kHz from on-axis to 30 degrees off-axis. While the Diatone is more typical of many FR's, requiring more toe-in to maintain output in the higher ranges.
I personally wouldn't be looking to add a tweet to my drivers unless there's a particular need. I'm designing the Alpair Gen 2. drivers to be more axis-positional-friendly. Given the fall-off performance in other FR units, I can understand why some DIYer's try to compensate for this effect by adding a tweet.
This goes some of the way to demonstrate my efforts over these years to develop and build more acoustically efficient cones; And to improve the linearity of driver power-trains. The goal is give DIY guys more useful and practical drivers.
Cheers,
Mark.
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Who knows?
would make an RP first. I design bathroom products and deal with injection moulding facilties in europe and asia.Mark, yes, would try a stand mount type first, possibly a modular design (that can be stacked). The priorities for me are a crossoverless design with great sound, great looks, good bass extention and decent SPLs.
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Well, you can tell whether a driver/cab will work based on a few facts, yes. At least, that's what it looks like to me
Ah! I read too much into your assertion.
GM
Who knows?
Cool! Back when I was designing injection molded parts for slot and R/C cars, I was limited to a few ounces, so no baffles.
Subjectively, 'best' was mat fiberglass laminated marine grade plywood, but more trouble than they were worth.GM
Shades of old Gilbert Briggs & his baffle experiements. They eventually decided on some form of stone IIRC, but he refused point-blank to have anything to do with it, on the principle that if it took 4 very large men to shift the thing, life was getting too short by far. And would be even shorter if he tried to move it. Definitely more trouble than it was worth.
Definitely more trouble than it was worth.
Yeah, the first solid surface washbasin range I designed was over engineered and needlessly heavy. There are ways to keep the cabinet walls pretty thin without losing strength or producing resonance. I am guessing that I could bring a bare cabinet(15 litre) in at around 4kg each
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