The only (currently) firm aspect to this project is my wish to make use of existing 10" scanspeak drivers. They're nice, but something of an unknown/unproven quantity (though I measured the TS parameters), as they're an OEM version, not something with lots of distortion charts etc available. Consequently, I've thought it safest to consider them only as low-ish woofers.
However, prompted by some of the suggestions above, I've looked around and found references to the late Wes Phillips (at the time, editor of stereophile) liking them crossed at 700hz in the original speakers. So I'd need to test for myself, but it looks like they'll be more flexible than I'd considered. Going a bit higher with them would indulge my preference for larger, dynamic drivers for the lower-midrange, and I'd also then be happier with using a smallish mid-range driver (+ tweeter). Or in fact going for 2-ways of some kind (yes including WAW, CD+horns etc).
Having the 10" drivers perform up into the lower midrange at the same time as handling the lowest stuff might not be quite so ideal, but I suppose subwoofer(s) might profitably be used if it were a problem, crossed in very low. I say that as the 10" drivers aren't particularly sensitive (or of huge diameter) for the lowest range, and I might also prefer subs for the very low stuff anyway due to flexibility in positioning (or randomly distributing them) to account for room issues.
Very interesting how this thread has evolved my thinking, and my awareness of the options. Thanks to all who have contributed suggestions!
Kev
However, prompted by some of the suggestions above, I've looked around and found references to the late Wes Phillips (at the time, editor of stereophile) liking them crossed at 700hz in the original speakers. So I'd need to test for myself, but it looks like they'll be more flexible than I'd considered. Going a bit higher with them would indulge my preference for larger, dynamic drivers for the lower-midrange, and I'd also then be happier with using a smallish mid-range driver (+ tweeter). Or in fact going for 2-ways of some kind (yes including WAW, CD+horns etc).
Having the 10" drivers perform up into the lower midrange at the same time as handling the lowest stuff might not be quite so ideal, but I suppose subwoofer(s) might profitably be used if it were a problem, crossed in very low. I say that as the 10" drivers aren't particularly sensitive (or of huge diameter) for the lowest range, and I might also prefer subs for the very low stuff anyway due to flexibility in positioning (or randomly distributing them) to account for room issues.
Very interesting how this thread has evolved my thinking, and my awareness of the options. Thanks to all who have contributed suggestions!
Kev
I assume your response is intended as sarcasm?…….when used properly, a compression driver will have significantly lower distortion products of all types and by design and mass, will not suffer power compression.…..this is not opinion but verifiable and measurable fact.Because the fatigue is there to begin with a CD?
So if you’re hearing response above 10khz is poor (even the best of us are tilted downwards anyways) all the MORE reason to consider a CD….more so a larger 1.4” to 2” driver capable of a 500hz crossover no problem……yes the speaker will be somewhat large but the results would be spectacular paired with a capable 15” woofer…..these are the things that the beat classic hifi configurations were born and made of…..effortless distortion free sound…..period.especially as I'm considering both full-range or CD for the mid-tweeter. I currently believe that either could work very well, but that the CD might be overkill for my purposes (and age related hearing loss); a reduction off-axis at high frequencies would not be a problem for a number of reasons. But no decisions made yet
Thanks,
Kev
Thanks again. Yes the CD is still a possibility, depending on what size I can live with, and the horn might bring useful things to the table. Whilst crossing my 10" bass drivers to 4" mid-tweeters would work in many ways, the rather abrupt change in size and dynamic capability of the two isn't something that I'm entirely at ease with, whereas a CD in a horn would likely have little trouble in that respect.
Were I to stay with conventional direct radiating drivers I'd probably prefer (rather than strictly need) to either add an intervening lower-midrange or use a bigger wide-range + a tweeter from about 6khz. Which doesn't allow for anything like ideal driver spacing with the tweeter, but does put the XO out of the most critical and sensitive ranges, which I know can work too. So I think both would be viable options.
Either way they'd both involve an extra 'way' for each speaker and (in an active system) an extra pair of amps. So the cost of a decent CD (or some of the other more exotic options) might be offset simply by convincing me that 2-ways are still acceptable. But I'd have to consider how big this would make everything.
Cheers,
Kev
Were I to stay with conventional direct radiating drivers I'd probably prefer (rather than strictly need) to either add an intervening lower-midrange or use a bigger wide-range + a tweeter from about 6khz. Which doesn't allow for anything like ideal driver spacing with the tweeter, but does put the XO out of the most critical and sensitive ranges, which I know can work too. So I think both would be viable options.
Either way they'd both involve an extra 'way' for each speaker and (in an active system) an extra pair of amps. So the cost of a decent CD (or some of the other more exotic options) might be offset simply by convincing me that 2-ways are still acceptable. But I'd have to consider how big this would make everything.
Cheers,
Kev
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It occurs to me that two of the possibilities so far suggested might also be combined: a widerange driver in a horn or significant waveguide. This post suggests that they could do fairly well, and might even have lower distortion than a CD - at least when only used at home hifi levels (which of course is the case for me). I've read a few references to CDs sounding a bit harsh in comparison to domes and cones, which of course doesn't mean they always do, just that some people feel they can do.
The lower cost and wider flexibility of a widerange driver might be useful, but the upper end might be less ideal than a CD and presumably the waveguide would need to be fairly big for a ~3" effective diameter throat. So this may or may not be practicable, but I'm mentioning it here partly in case it attracts any informed comments and partly so that I don't forget to look into it further.
The lower cost and wider flexibility of a widerange driver might be useful, but the upper end might be less ideal than a CD and presumably the waveguide would need to be fairly big for a ~3" effective diameter throat. So this may or may not be practicable, but I'm mentioning it here partly in case it attracts any informed comments and partly so that I don't forget to look into it further.
Interesting. It's hard to tell without a more in-depth look, but my guess would be that, after bringing its sensitivity up, the wide-band has more Xmax left over, or (similarly) the CDs run out of grunt due to geometric contraints in the phase plug. For the sensitivity to be so high, the phase plug would have to be right up against the cone, and therefore even the tiniest displacement from low frequencies would modulate the gain at hf.
Thanks, more food for thought!
As has this whole thread been; many thanks to all who contributed - as a result I've more or less decided that I'd like to try a tweeter-less design. Crossed at 'somewhere' between about 300hz and 800hz. Exactly what that may be is still open to question, but likely either a full/wide-range or a CD for the top-end (pending a bit of research on some of the more costly/exotic alternatives).
My 10" bass drivers are perhaps not too big for crossing direct to 3inch-4inch full/wide-range midtweeters, especially if crossed towards the upper end of my proposed range. Though maybe a mid-sized woofer between the two would benefit smoothness of transition and relieve the lower-midrange from entanglement with lower bass duties, so I'm still tempted for this being a 3-way.
Or else, an appropriate CD in suitable horn would mesh more easily with 10" woofers as a 2-way, and in some ways seems better. But I have little experience of them (outside of pre-built PA speakers) and some doubts about suitability etc. at mere hifi-levels, compared to drivers intended for it, so much more research needed on those before I decide either way.
Cheers,
Kev
As has this whole thread been; many thanks to all who contributed - as a result I've more or less decided that I'd like to try a tweeter-less design. Crossed at 'somewhere' between about 300hz and 800hz. Exactly what that may be is still open to question, but likely either a full/wide-range or a CD for the top-end (pending a bit of research on some of the more costly/exotic alternatives).
My 10" bass drivers are perhaps not too big for crossing direct to 3inch-4inch full/wide-range midtweeters, especially if crossed towards the upper end of my proposed range. Though maybe a mid-sized woofer between the two would benefit smoothness of transition and relieve the lower-midrange from entanglement with lower bass duties, so I'm still tempted for this being a 3-way.
Or else, an appropriate CD in suitable horn would mesh more easily with 10" woofers as a 2-way, and in some ways seems better. But I have little experience of them (outside of pre-built PA speakers) and some doubts about suitability etc. at mere hifi-levels, compared to drivers intended for it, so much more research needed on those before I decide either way.
Cheers,
Kev
I am following this thread with interest. I am currently planning a FAST/WAW using SB WO24p crossed to 10F/8414 (drivers chosen primarily from what I have available). Crossover will be minidsp with a 2x200as1 am p for the bass units and a diy f6 for the full rangers. I am curious what are your thoughts on bridging the 10” and FR drivers? I was thinking a 4-500 hz crossover, using a sealed or midTL box for the full ranges, with sealed boxes for the bass units and possibly Linkwitz transform.
I suppose where one chooses to make the (inevitable) compromises is quite a personal thing, really. I've now decided that for me (my small listening position, my hearing and my preferences) I could accept a small widerange driver handling what would normally be tweeter duties, and it would be excellent for the upper-midrange too. However, in the lower-midrange I personally prefer larger drivers for their better dynamics, at least 6.5" or so, and by preference would have smaller steps in driver size, which is why I'd personally consider a third driver between the bottom and top ones..... I am curious what are your thoughts on bridging the 10” and FR drivers? I was thinking a 4-500 hz crossover, using a sealed or midTL box for the full ranges, with sealed boxes for the bass units and possibly Linkwitz transform.
Alternatives would be to cross my 10" higher, say 800hz or so, or use a bigger widerange for the top end. Both these would work, but then bring different compromises to consider. I don't really want the driver taxed with producing all the deep bass to be used much higher as well. A high-frequency driver that was bigger would inevitably be more of a compromise as a tweeter replacement, though might still be good enough in some situations; I would have to do research and testing. (Then there are very different answers, such as horns, CDs etc, which are their own discussion).
In many other respects the 10"- 4" combo is not bad at all, so I've not entirely rejected it. Placed adjacently, the two drivers don't exceed the ideal 1/4 wavelength centre-to-centre spacing until nearly 500hz, and many people would go beyond that without very much concern. A 10" driver also isn't showing much reduction in dispersion by 700hz or so, and so would transition to the 4" quite seamlessly in terms of room reflections and off-axis listening. I can see why it is a popular option over on the full-range forum (such as the RS-225 crossed to a 10F), just not sure it is what I personally favour.
Those are my thoughts anyway, I'm sure that others will have other insights and other preferences. Possibly even see flaws in mine; I've some experience but am not an expert.
Kev
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Spurred on by this, I stuck an alpair 11ms in a closed cabinet and am testing it again. This has (very roughly) a 4.5" to 5" diameter cone. My first impression is that it sounds OK but unlike previous tests, this time I've compared it more directly to both a comparably sized 2-way with tweeter and an alpair 5.3 by itself. Not yet a blind test, but these have (to my ears) quite a noticeably better top end, so I'm reasonably confident it isn't imagined.A high-frequency driver that was bigger would inevitably be more of a compromise as a tweeter replacement, though might still be good enough in some situations; I would have to do research and testing
I will carry on testing, but suspect that I would prefer a smaller full-range for the top end. But if a larger upper-midrange were to be used, I would probably want a tweeter myself - likely in a waveguide for directivity. Which is fine really; it could still be done whilst avoiding the important frequency range with crossovers.
Would it be feasible to use the 11 ms for midrange with a smaller FR eg the 5.3 or 10f for the top end? Are you planning to cross them passively or with dsp?
It seems feasible to me. Though if the 11MS was only employed up to the upper-midrange, it wouldn't cover many octaves and so I'd likely prefer bigger conventional mid/mid-bass drivers for the job.
But if using it right through the important range (say up to 6khz) that would take more advantage of its wide-range capabilities. It'd probably then make more sense to use a tweeter above it, but a small cone driver could also work and might match the 11MS's directivity better (without needing a waveguide). I'd have to look at the driver's characteristics and do some simulations to check that one out.
That latter would be a 3-way, but with crossover points that in some terminology might be considered a woofer and tweeter assisted widerange ( a WATAW? 🙂 ). I'd imagine less palatable to those who prefer no crossover or around 1/4 wavelength crossovers/driver-spacing, but at least it still addresses the basic aim of avoiding crossovers in the most critical regions.
Personally I'm not too troubled by the concept of tweeter assistance. I have a pair of 2-way bookshelves that I bought in the late 80s or early 90s that use a 6" driver crossed first order at 6khz to a tweeter; I assume it is due to the fairly high and gentle slope of their crossover, but my hearing isn't able to distinguish anything obvious that would reveal there being separate drivers, irrespective of the listening axis etc (within reason). Perhaps a bit more care is needed to avoid high-frequency room reflections, due to the rather dramatic change in dispersion between the drivers, but there would be ways around that with waveguides etc.
But if using it right through the important range (say up to 6khz) that would take more advantage of its wide-range capabilities. It'd probably then make more sense to use a tweeter above it, but a small cone driver could also work and might match the 11MS's directivity better (without needing a waveguide). I'd have to look at the driver's characteristics and do some simulations to check that one out.
That latter would be a 3-way, but with crossover points that in some terminology might be considered a woofer and tweeter assisted widerange ( a WATAW? 🙂 ). I'd imagine less palatable to those who prefer no crossover or around 1/4 wavelength crossovers/driver-spacing, but at least it still addresses the basic aim of avoiding crossovers in the most critical regions.
Personally I'm not too troubled by the concept of tweeter assistance. I have a pair of 2-way bookshelves that I bought in the late 80s or early 90s that use a 6" driver crossed first order at 6khz to a tweeter; I assume it is due to the fairly high and gentle slope of their crossover, but my hearing isn't able to distinguish anything obvious that would reveal there being separate drivers, irrespective of the listening axis etc (within reason). Perhaps a bit more care is needed to avoid high-frequency room reflections, due to the rather dramatic change in dispersion between the drivers, but there would be ways around that with waveguides etc.
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Well after much research and deliberation, I'm being attracted to compression drivers (in horns/waveguides) as ticking more of my boxes than other options. I've a lot still to learn, but when used at lower (home hifi-level) SPL they 'seem' to offer many of the advantages of small full/wide-range drivers used as mid-tweeters but with a few added advantages in things like clean headroom/dynamics, and in perhaps in higher-frequency dispersion. Possibly also in distortion and in directivity control, though there is overlap and contention around such things.
The (inevitable) cost includes extra size, a lot more complexity to learn about and juggle, and more money. The crossover point might also (arguably) be lower with a full-range mid-tweeter than with a compression-driver (without spending lots on the latter), but only by a few hundred herts so I'm not too troubled by that. the Center-to-centre distance might also be a bit bigger when using waveguides, but there are flat rectangular types that would keep this quite minimal.
The (inevitable) cost includes extra size, a lot more complexity to learn about and juggle, and more money. The crossover point might also (arguably) be lower with a full-range mid-tweeter than with a compression-driver (without spending lots on the latter), but only by a few hundred herts so I'm not too troubled by that. the Center-to-centre distance might also be a bit bigger when using waveguides, but there are flat rectangular types that would keep this quite minimal.
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