The GF200 is only 83db/W using a single coil, and Qts is high but it works quite well in a reasonable sealed volume. Average xmax though winISD gives a good F3. The only other I can think of is a Scanspeak 10, i forget the model...but its expensive inefficient and has a HEAVY cone. Maybe someone will recall the model. If i recall it also works nicely in about a cubic foot sealed volume. But its too costly for me! The GF200 is the next driver im going to try out, after trying to find a 8 which will rock in a sealed box without much success.
I've had chance to do a bit more simulating - this time with the linkwitz transform and a SPL of 84dB@1m. The attached chart is for three drivers with the LT pushing them all to their respective max cone excursion (in order of lowest to highest cut-off):
#Blue - SB acoustics 12" sub SB34SWNRX
#Yellow - Peerless 12" woofer SLS-315 830669
#White - SEAS L26ROY D1001
Theres surprisingly little difference; between about 30hz and 36hz. The peerless has around 2/3rds the Xmax but is larger than the ROY so can almost match it, the SB is also bigger than the ROY but has slightly less Xmax so is not that far ahead. However the SB is a sub and I've not seen it suggested that it has the low distortion of the smaller coned ROY so I'd be less confident using it up to mid crossover point. As was pointed out above, the peerless is a woofer so should be fine, and although the ROY is a sub it has proven itself.
The peerless is a bit more sensitive than the ROY and much cheaper, but athe main difference is probably box volume. For a native Qtc of 0.7 the peerless needs a box volume of over 190L, whilst the seas only around 20L. With sufficient amp and driver power handling, the LT can correct the Qtc allowing much smaller boxes, so it doesn't need to be a huge issue.
BUT I'd always believed that (all else being equal) bigger boxes and lower pressures/stresses on the cone were best, so if anything I'd be inclined to use the LT to let me put the ROY in a bigger box than necessary rather than the Peerless in a smaller one. Although, they'd probably end up about the same volume that way, so would it actually matter?
Many thanks
Kev
#Blue - SB acoustics 12" sub SB34SWNRX
#Yellow - Peerless 12" woofer SLS-315 830669
#White - SEAS L26ROY D1001
Theres surprisingly little difference; between about 30hz and 36hz. The peerless has around 2/3rds the Xmax but is larger than the ROY so can almost match it, the SB is also bigger than the ROY but has slightly less Xmax so is not that far ahead. However the SB is a sub and I've not seen it suggested that it has the low distortion of the smaller coned ROY so I'd be less confident using it up to mid crossover point. As was pointed out above, the peerless is a woofer so should be fine, and although the ROY is a sub it has proven itself.
The peerless is a bit more sensitive than the ROY and much cheaper, but athe main difference is probably box volume. For a native Qtc of 0.7 the peerless needs a box volume of over 190L, whilst the seas only around 20L. With sufficient amp and driver power handling, the LT can correct the Qtc allowing much smaller boxes, so it doesn't need to be a huge issue.
BUT I'd always believed that (all else being equal) bigger boxes and lower pressures/stresses on the cone were best, so if anything I'd be inclined to use the LT to let me put the ROY in a bigger box than necessary rather than the Peerless in a smaller one. Although, they'd probably end up about the same volume that way, so would it actually matter?
Many thanks
Kev
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I wonder how this project has gone?
SEAS has published a 3-way with L26Roy4 and their new Excel coaxial. ROY is crossed at 200Hz LR4. The box is closed 16 liter and low end eq is used. DSP and active amping is provided by Hypex. Here is a link to application note of KingRO4Y http://www.seas.no/images/stories/excel/coaxial/app_note/KingRO4Y_doc.pdf
A complete speaker was presented at RMAF 2013 read a report
SEAS has published a 3-way with L26Roy4 and their new Excel coaxial. ROY is crossed at 200Hz LR4. The box is closed 16 liter and low end eq is used. DSP and active amping is provided by Hypex. Here is a link to application note of KingRO4Y http://www.seas.no/images/stories/excel/coaxial/app_note/KingRO4Y_doc.pdf
A complete speaker was presented at RMAF 2013 read a report
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Thanks for the info, thats most interesting!!
Frustratingly, management incompetence at work has meant that my job/income has suddenly (and unnecessarily) become quite tenuous, so other things have taken priority over this project lately. However prior to that, I won some used Scanspeak 26W bass drivers on ebay, so if/when the project resumes I will have to decide if I'll be using those or considering the L26 Roys again; your post may be very useful there, so thanks indeed for it!
I do still hope that it will resume at some point, when I can spare the time again. If the bass drivers turn out to be okay then I will already have most of the costly components; I'd really just need the transformers and reservoir capacitors for the amp's power supplies - after that just small stuff and the time to design and make it all.
Cheers
kev
Frustratingly, management incompetence at work has meant that my job/income has suddenly (and unnecessarily) become quite tenuous, so other things have taken priority over this project lately. However prior to that, I won some used Scanspeak 26W bass drivers on ebay, so if/when the project resumes I will have to decide if I'll be using those or considering the L26 Roys again; your post may be very useful there, so thanks indeed for it!
I do still hope that it will resume at some point, when I can spare the time again. If the bass drivers turn out to be okay then I will already have most of the costly components; I'd really just need the transformers and reservoir capacitors for the amp's power supplies - after that just small stuff and the time to design and make it all.
Cheers
kev
hi Eldam,
yes that could work (if I'm understanding correctly), so thanks for the suggestion. But currently I'm not able to spend any time designing or making stuff like that so it would be a decision for the future really. Much about my project could change with circumstances, so I'll have to see what unfolds first.
Cheers
Kev
yes that could work (if I'm understanding correctly), so thanks for the suggestion. But currently I'm not able to spend any time designing or making stuff like that so it would be a decision for the future really. Much about my project could change with circumstances, so I'll have to see what unfolds first.
Cheers
Kev
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