im running some calculations on a possible mocro subwoofer using the tangband W6-2100 6.5 inch subwoofer
Tang Band W6-2100 6-1/2" RBM Flat Panel Subwoofer 4 Ohm
and a pair of 6.5 inch passive radiators in a 10- 15 litre box. the box would be barely bigger than the driver surrounds.. so.. really, really small.
its my first time working with passive radiators (theoretically at this point)
i was looking at the nice cheap dayton audio 6.5 inch jobbies here:
Dayton Audio SD175-PR 6-1/2" Passive Radiator
their excursion is a tad low (9mm vs 10 mm for the tang band) but there will be two of them so acceptable i think.
anyway, being a bit of a (total) noob in the theoretical side of speaker design, im a bit lost in winisd.
ive input the driver parameters, and simulated a vented enclosure in a 15 litre box. with a tuning frequency of 26 hz, for starters. the response curve looks great for such a small box. , down only 3db at 30 hz, and 10db at 20hz.
using the effective diameter of two of the passive radiators, i get a vent 18.1cm diameter and 734 cm long
however, the air mass ( and hence PR mass ) is a feeble 17 grams.
given the starting mass of the pair of PR's is 75 grams, working backwards, the equivalent vent would be 3.3 metres long, and the box would be tuned to circa 15 hz.
obviously this is useless. i may as well not bother with the PR's
making the box larger seems to make this even worse.
bringing the box right down to 5 litres, i get a more massive vent and therefore a heavier PR, but a) its impossible to make a box that small for these cones, and b) the freq resp. graph looks horrible, and worse than a single driver in a 10 litre sealed box.
what am i missing? where on earth do i find a pair of 6.5 inch passive radiators that only weigh 8.5 grams each ?!
considering eminence sell a passive radiator at 8 inches and a few hundred grams in weight, it seems odd my design with a slightly smaller cone is calling for unobtanium light PR's
its very likely i have just entirely messed up the calculation process... ?
on a related note, in winisd i get no SPL curve (says i need to input the spl of the speaker? its not supplied for the tang band speakers..)
i also cannot find a cone excursion graph, which seems quite a critical thing to check..
any brainpower you lot can lend me would be most appreciated as always.
i need a miniscule sub as the other half doesnt want more boxes in the room, and im only trying to add a bit of grunt and take the load off my modest mission 780'se's running on a gainclone amp i built. i figure a pair of these might be just the ticket if i can figure out the maths.
alternatively, should i just stick a pair of these drivers in small sealed boxes and eq the heck out of them? they have reasonable excursion and the curves are not bad even in a 10 litre enclosure. id need to add 5-6db at 30 hz and 3db at 20hz to match the PR's. not that id go that low really.
it would certainly be a simpler build.
Tang Band W6-2100 6-1/2" RBM Flat Panel Subwoofer 4 Ohm
and a pair of 6.5 inch passive radiators in a 10- 15 litre box. the box would be barely bigger than the driver surrounds.. so.. really, really small.
its my first time working with passive radiators (theoretically at this point)
i was looking at the nice cheap dayton audio 6.5 inch jobbies here:
Dayton Audio SD175-PR 6-1/2" Passive Radiator
their excursion is a tad low (9mm vs 10 mm for the tang band) but there will be two of them so acceptable i think.
anyway, being a bit of a (total) noob in the theoretical side of speaker design, im a bit lost in winisd.
ive input the driver parameters, and simulated a vented enclosure in a 15 litre box. with a tuning frequency of 26 hz, for starters. the response curve looks great for such a small box. , down only 3db at 30 hz, and 10db at 20hz.
using the effective diameter of two of the passive radiators, i get a vent 18.1cm diameter and 734 cm long
however, the air mass ( and hence PR mass ) is a feeble 17 grams.
given the starting mass of the pair of PR's is 75 grams, working backwards, the equivalent vent would be 3.3 metres long, and the box would be tuned to circa 15 hz.
obviously this is useless. i may as well not bother with the PR's
making the box larger seems to make this even worse.
bringing the box right down to 5 litres, i get a more massive vent and therefore a heavier PR, but a) its impossible to make a box that small for these cones, and b) the freq resp. graph looks horrible, and worse than a single driver in a 10 litre sealed box.
what am i missing? where on earth do i find a pair of 6.5 inch passive radiators that only weigh 8.5 grams each ?!
considering eminence sell a passive radiator at 8 inches and a few hundred grams in weight, it seems odd my design with a slightly smaller cone is calling for unobtanium light PR's
its very likely i have just entirely messed up the calculation process... ?
on a related note, in winisd i get no SPL curve (says i need to input the spl of the speaker? its not supplied for the tang band speakers..)
i also cannot find a cone excursion graph, which seems quite a critical thing to check..
any brainpower you lot can lend me would be most appreciated as always.
i need a miniscule sub as the other half doesnt want more boxes in the room, and im only trying to add a bit of grunt and take the load off my modest mission 780'se's running on a gainclone amp i built. i figure a pair of these might be just the ticket if i can figure out the maths.
alternatively, should i just stick a pair of these drivers in small sealed boxes and eq the heck out of them? they have reasonable excursion and the curves are not bad even in a 10 litre enclosure. id need to add 5-6db at 30 hz and 3db at 20hz to match the PR's. not that id go that low really.
it would certainly be a simpler build.
thanks for the pointer! the passive radiator setting in winiso pro seems to give a massively different result. Unfortunately the hard drop off in gain is offputting! goes from -4db at 40 hz down to -15 at 30.
are there any rules-of-thumb as to how much mass you can load on a PR ?
i assume heavier loading places more demands on the woofer?
ive also discovered i can use a linkwitz transform (which admittedly i know almost nothing about) to try and approach the performance of the PR using a sealed box. its very interesting to see the massive amounts of cone excursion generated by this method... im just randomly changing parameters at the moment to see what i can get while keeping under the xmax of the driver.
if anyone knows of a 6.5 inch driver with 3cm of cone travel ill be sorted!
seriously though, any amazing , cheap 6.5 inch sub cones out there which might be suitable for such a project, ive not heard of? since the last time i used tangband their prices have tripled...
are there any rules-of-thumb as to how much mass you can load on a PR ?
i assume heavier loading places more demands on the woofer?
ive also discovered i can use a linkwitz transform (which admittedly i know almost nothing about) to try and approach the performance of the PR using a sealed box. its very interesting to see the massive amounts of cone excursion generated by this method... im just randomly changing parameters at the moment to see what i can get while keeping under the xmax of the driver.
if anyone knows of a 6.5 inch driver with 3cm of cone travel ill be sorted!
seriously though, any amazing , cheap 6.5 inch sub cones out there which might be suitable for such a project, ive not heard of? since the last time i used tangband their prices have tripled...
im trying to enter the parameters of the anarchy driver into the winisd pro alpha, but every time i hit save it says there are errors with loads of the parameters, and that i should consult the (nonexistant) help.
i get the same result when i try and enter the specs of another tangband sub.
alpha version problem? bit limiting if i can only use the provided speaker profiles.
i get the same result when i try and enter the specs of another tangband sub.
alpha version problem? bit limiting if i can only use the provided speaker profiles.
ok so i have something promising in winisd, but ridiculous if you think about it;
a single 6.5 inch tangband sub in a 20 litre enclosure with 3 8-inch passive radiators, each mass loaded with 250 grams.
there has to be an issue with asking a 6.5 inch sub to shift 750 grams of mass..?
heck i dunno if the PR's can even support 250 grams each without freaking out.
also the idea of so much passive and so little driver seems wrong.
however it graphs well. run at 120w it seems to go down to 30 hz at -2db and on to 25 hz at -6db, before dropping like a stone (ive got a 4th order butterworth highpass at 22 hz to keep excursion under control)
spl is claimed at around 102db down to 40hz, 100db at 30hz and 95db at 25 hz.
seems bonkers for a 6.5 inch driver in a 25cm cube.
if i can ill attach the winisd file
a single 6.5 inch tangband sub in a 20 litre enclosure with 3 8-inch passive radiators, each mass loaded with 250 grams.
there has to be an issue with asking a 6.5 inch sub to shift 750 grams of mass..?
heck i dunno if the PR's can even support 250 grams each without freaking out.
also the idea of so much passive and so little driver seems wrong.
however it graphs well. run at 120w it seems to go down to 30 hz at -2db and on to 25 hz at -6db, before dropping like a stone (ive got a 4th order butterworth highpass at 22 hz to keep excursion under control)
spl is claimed at around 102db down to 40hz, 100db at 30hz and 95db at 25 hz.
seems bonkers for a 6.5 inch driver in a 25cm cube.
if i can ill attach the winisd file
thats a very useful link. they have the PR's im after.. however ive still yet to find any european stockist of:
https://www.parts-express.com/pedocs/specs/264-954--w6-2100-spec-sheet.pdf
which, despite a lower excursion limit, simulates rather better than the 1139, plus has slightly higher power handling, and is supposedly more rugged.
Ridiculous. according to the mighty google (well at least its first 20 or so pages) that driver truly isnt available in Europe. not even on ebay.
partsexpress will ship it here (italy) but shipping/taxes/duties cost over 200 dollars for a pair of them.
390 dollars for 2 6.5-inch drivers is rather hard to swallow!
its a real shame cos i get at least 6 db more at 25 hz with those , over the 1139's. plus much better power handling within excursion limits, and the cone and 3x PR's bottom out almost perfectly at the same power level (130w)
with the 1139, i need a 10l bigger enclosure to get the best freq-response, and the cone bottoms out at 75 watts, leaving lots of excursion on the table for the PR's.
partsexpress will ship it here (italy) but shipping/taxes/duties cost over 200 dollars for a pair of them.
390 dollars for 2 6.5-inch drivers is rather hard to swallow!
its a real shame cos i get at least 6 db more at 25 hz with those , over the 1139's. plus much better power handling within excursion limits, and the cone and 3x PR's bottom out almost perfectly at the same power level (130w)
with the 1139, i need a 10l bigger enclosure to get the best freq-response, and the cone bottoms out at 75 watts, leaving lots of excursion on the table for the PR's.
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