Having bimbled around with other possibilities I'm coming back to building a pair of compact WAWs with a pair of Alpair 5.3 full-ranges and a pair of scanspeak 15W/8530k01 drivers.
I'm quite new to full-range drivers, so out of my comfort zone using such tiny speakers as the 5.3s covering a wide range (I was somewhat with Troels Gravesen on liking reasonably sized mid-ranges in conventional 3-ways). They have a relatively large frame/border, but the alpair 5.3's actual cone is noticeably less than 2.5" diameter, and the soft rubber bits don't take them much over, though they've sometimes been categorised as 3" on this forum, as probably befits their real-world capability.
That said, I'm sure it'll be fine; massively high SPLs aren't needed as the speakers will be situated close up (on a desk). Also, the 15Ws are properly good performers in their own right and will also go quite high if needed; well up into conventional 2-way XO territory if so wished (though that isn't the intention). So great flexibility of XO-point according to taste.
On the low end, it seems the 15Ws do better than one might think for their size. They would even take some EQ'd extension at the SPLs intended. So really both drivers have rather good wide range capabilities. Additionally, for added flexibility in the future (if/when I get a place where high SPLs are a possibility) I want to plan the design such that these 2-way WAWs could be high-passed for use with either a low 10" woofer or perhaps a subwoofer configuration.
Those are my present intentions anyway, and any thoughts or comments could be helpful as I'm starting to think seriously about the design. Though it will be slow to actually start, as I'm sorting out upstream components as a priority.
I'm quite new to full-range drivers, so out of my comfort zone using such tiny speakers as the 5.3s covering a wide range (I was somewhat with Troels Gravesen on liking reasonably sized mid-ranges in conventional 3-ways). They have a relatively large frame/border, but the alpair 5.3's actual cone is noticeably less than 2.5" diameter, and the soft rubber bits don't take them much over, though they've sometimes been categorised as 3" on this forum, as probably befits their real-world capability.
That said, I'm sure it'll be fine; massively high SPLs aren't needed as the speakers will be situated close up (on a desk). Also, the 15Ws are properly good performers in their own right and will also go quite high if needed; well up into conventional 2-way XO territory if so wished (though that isn't the intention). So great flexibility of XO-point according to taste.
On the low end, it seems the 15Ws do better than one might think for their size. They would even take some EQ'd extension at the SPLs intended. So really both drivers have rather good wide range capabilities. Additionally, for added flexibility in the future (if/when I get a place where high SPLs are a possibility) I want to plan the design such that these 2-way WAWs could be high-passed for use with either a low 10" woofer or perhaps a subwoofer configuration.
Those are my present intentions anyway, and any thoughts or comments could be helpful as I'm starting to think seriously about the design. Though it will be slow to actually start, as I'm sorting out upstream components as a priority.
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As adason says, they need to be in speparte spaces. The A5 can be sealed or a midTL.
How sensitive is the Scan?
Passive or line level XO?
dave
How sensitive is the Scan?
Passive or line level XO?
dave
Makes passive difficult. Usuulaly you want the woofer some 2-4dB more sensitive than the midTweeter. XO somewhere around the bafflestep.
dave
dave
Thanks everyone. The 15Ws aren't especially sensitive unfortunately, but I would like the XO to be active so that part should be okay. If it works out, I'm actually hoping the source will be a PC and the XO could then be done in software; there seem to be some decent multi-way sound-cards and DACs around so that is the hope, anyway. It is something I did in the past with conventional 3-ways, albeit on the cheap and a completely different operating system, so I feel it could work here too.
As to the XO frequency, I shall have to do some testing. I've seen it suggested that the A5.3s can be crossed as low as 250hz, though IIRC that was in fairly large enclosures with better bass support than I'd likely get in a compact one. I'm also not entirely comfortable with little drivers going so low, and in this case the 'woofers' are quite small and also very capable higher up, so at this stage I'm imagining the optimum XO frequency might be somewhere towards the upper end of WAW territory; maybe around 500hz for example. With a software approach, baffle-step correction (and the XO) would be easy to do, but I'd like to get the box itself pretty much appropriate and then only tweak slightly in software if required.
Yes the drivers will have separate chambers. Currently I'm thinking sealed/closed; I've always liked the characteristics and compactness. Maybe the 15W could end up in a ported or some flavour of TL box if these turn out to suit it better (I've only used it as a midrange before, so not yet explored optimising its bass), but if not then sealed with EQ would be my favourite.
Thanks again, it is all helping to define the plan!
Kev
As to the XO frequency, I shall have to do some testing. I've seen it suggested that the A5.3s can be crossed as low as 250hz, though IIRC that was in fairly large enclosures with better bass support than I'd likely get in a compact one. I'm also not entirely comfortable with little drivers going so low, and in this case the 'woofers' are quite small and also very capable higher up, so at this stage I'm imagining the optimum XO frequency might be somewhere towards the upper end of WAW territory; maybe around 500hz for example. With a software approach, baffle-step correction (and the XO) would be easy to do, but I'd like to get the box itself pretty much appropriate and then only tweak slightly in software if required.
Yes the drivers will have separate chambers. Currently I'm thinking sealed/closed; I've always liked the characteristics and compactness. Maybe the 15W could end up in a ported or some flavour of TL box if these turn out to suit it better (I've only used it as a midrange before, so not yet explored optimising its bass), but if not then sealed with EQ would be my favourite.
Thanks again, it is all helping to define the plan!
Kev
FYI/FWIW, the 15W's directivity (DI) XO match-up is ~331, 976, 1677 Hz.
Need the 5.3's VC diameter to find its match ups.
Need the 5.3's VC diameter to find its match ups.
Ah, thank you very much, GM. I confess to being quite rusty (I don't build speakers very frequently, and am no expert to begin with) but now that you mention it, the directivity relationship with XO is ringing some quite large bells; I will need to do some revision.
In my desktop scenario, the angles to the listening position are fairly constrained, and also will be near-field in the sense of most off-axis and indirect room reflections being less relevant. But I must remember the intention for these to be flexible - enough to be used as room speakers in the future, in combo with bigger woofer or subwoofer cabinets.
Thanks again,
Kev
In my desktop scenario, the angles to the listening position are fairly constrained, and also will be near-field in the sense of most off-axis and indirect room reflections being less relevant. But I must remember the intention for these to be flexible - enough to be used as room speakers in the future, in combo with bigger woofer or subwoofer cabinets.
Thanks again,
Kev
Just gathering some more thoughts and information to help later on. For general reference, this is the 15W/8530k01 frequency response chart:
so it stays pretty flat and well behaved between 100hz and 1khz, and there is little difference between on and off axis until beyond that point. In a traditional 3-way I've used it up to 2.5khz without noticing much difference as one moves around.
This is for the alpair 5.3:
which is flat enough (for me) right up to pretty high frequencies. Unfortunately the chart doesn't show off-axis performance, but based on similar sized full-ranges I might expect on and off axis to be relatively indistinguishable until around 4 or 5khz, and not start beaming until about twice that. I'm interested to see how flat it supposedly stays at the low end too; maybe I will reserve judgement on how low I want to use it.
Obviously these are only manufacturer's charts and not in my (as yet undecided) enclosures. But they suggest there'll be a lot of overlap between these drivers, and so a wide range of sensible XO frequencies, even with shallow slopes. For physical separation of the drivers, their minimum centre-to-centre distance is less than 5", so even if one were to aim for an ideal maximum of a 1/4 wavelength that would still allow crossing up to about 660Hz which is fine for a WAW (and obviously many people cross much higher than 1/4 wavelength in traditional 2-ways etc).
In some ways it would be better if they didn't disperse so widely over quite so much of their range, but at least it should make pairing them together less difficult. Perhaps ideally I'd try to reduce and control the dispersion, but for the intended near-field use (in which room effects should be less significant) that probably wouldn't warrant the extra complexity and potential increase in size. I suppose going the other way then for off/on-axis consistency throughout (my) audible frequency range a super-tweeter (say over 5khz) could be employed, but maybe there'd be little value in doing so for my purposes.
so it stays pretty flat and well behaved between 100hz and 1khz, and there is little difference between on and off axis until beyond that point. In a traditional 3-way I've used it up to 2.5khz without noticing much difference as one moves around.
This is for the alpair 5.3:
which is flat enough (for me) right up to pretty high frequencies. Unfortunately the chart doesn't show off-axis performance, but based on similar sized full-ranges I might expect on and off axis to be relatively indistinguishable until around 4 or 5khz, and not start beaming until about twice that. I'm interested to see how flat it supposedly stays at the low end too; maybe I will reserve judgement on how low I want to use it.
Obviously these are only manufacturer's charts and not in my (as yet undecided) enclosures. But they suggest there'll be a lot of overlap between these drivers, and so a wide range of sensible XO frequencies, even with shallow slopes. For physical separation of the drivers, their minimum centre-to-centre distance is less than 5", so even if one were to aim for an ideal maximum of a 1/4 wavelength that would still allow crossing up to about 660Hz which is fine for a WAW (and obviously many people cross much higher than 1/4 wavelength in traditional 2-ways etc).
In some ways it would be better if they didn't disperse so widely over quite so much of their range, but at least it should make pairing them together less difficult. Perhaps ideally I'd try to reduce and control the dispersion, but for the intended near-field use (in which room effects should be less significant) that probably wouldn't warrant the extra complexity and potential increase in size. I suppose going the other way then for off/on-axis consistency throughout (my) audible frequency range a super-tweeter (say over 5khz) could be employed, but maybe there'd be little value in doing so for my purposes.
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Right, the pioneer's apparently needed well controlled directivity out to the ~ -25 dB point of audible human hearing perception to minimize the number of speaker systems required to fill a large theater, PA app with a high speech intelligibility and for folks like me using 1st order for HIFI/HT apps.
Right, ideally no reflections till behind the listener's ears, then diffuse as much as practical and why I prefer CD horns and/or wide baffles.
F-6 horn mouth, baffle frequency (Imperial): 10^6/(wall angle*mouth width)
(Metric): (2.54*10^6)/(wall angle*mouth width)
Unfortunately I think horns and wide baffles go against the compact desktop objectives here. Though maybe as a nod to the baffle, I could arrange them in a kind of console with a continuous face that includes the left speaker, monitor and right speaker. The close listening distance will hopefully put a lot of later room reflections into the distant background. Probably the main foe would be the desktop, but there may be ways of countering that as it is fairly specific.
Though before settling on WAW I got a larger pair of alpair 11MS to try. Perhaps in the future these may be used in bigger cabinets (possibly with a woofer and even tweeter to assist) where horns and big baffles would be more suitable.
Though before settling on WAW I got a larger pair of alpair 11MS to try. Perhaps in the future these may be used in bigger cabinets (possibly with a woofer and even tweeter to assist) where horns and big baffles would be more suitable.
I'm sure it will, in fact it has already been very helpful for my plans.
I'm now of the opinion that these desktop speakers will NOT double (in the future) as the upper pair of a larger 3-way, as initially envisaged; I would actually want more control over the directivity of larger room speakers. Which also means that I can be more focused (less compromised) here and now on the desktop design, especially with respect to their compactness and SPL requirements.
Cheers,
Kev
I'm now of the opinion that these desktop speakers will NOT double (in the future) as the upper pair of a larger 3-way, as initially envisaged; I would actually want more control over the directivity of larger room speakers. Which also means that I can be more focused (less compromised) here and now on the desktop design, especially with respect to their compactness and SPL requirements.
Cheers,
Kev