Good catch Freddi, you are indeed correct. I think the comparison of the two curves is interesting, because you can see what a small difference a large difference in Qts. makes on HF response. Now I just need to figure out how to edit my website!
pj
www.wildburroaudio.com
great sounding, affordable fullrange loudspeaker drivers
pj
www.wildburroaudio.com
great sounding, affordable fullrange loudspeaker drivers
Nope, no Alnico. Not yet anyway. . . Ya' can't have it all for $75 a pair!
pj
www.wildburroaudio.com
pj
www.wildburroaudio.com
sorry , meant future alnico
Scottmoose said:
Indeed........
MLTL
L = 46.5"
WxD = 232.85"^2
zdriver = 8"
zport = near/at the bottom
dport = 6"
Lport = 0.75"
stuffing density = 0.2 lbs/ft^3 shown
ML-horn
L = 60"
top WxD = 33.29"^2
bottom WxD = 332.85"^2
zdriver = 23.6"
zport = near/at the bottom
dport = 5"
Lport = 0.75"
stuffing density = 0.2 lbs/ft^3 shown
All dims approximate.
GM
Attachments
this is a nice looking driver
BetsyK as it appears when the box is first opened
here's a larger and better picture showing the dustcap
driver is well protected by its shipping carton
besides the very nice cone and concave dustcap there's reasonable heft to BetsyK
it has a large spider
BetsyK as it appears when the box is first opened
An externally hosted image should be here but it was not working when we last tested it.
here's a larger and better picture showing the dustcap
An externally hosted image should be here but it was not working when we last tested it.
driver is well protected by its shipping carton
An externally hosted image should be here but it was not working when we last tested it.
besides the very nice cone and concave dustcap there's reasonable heft to BetsyK
An externally hosted image should be here but it was not working when we last tested it.
it has a large spider
An externally hosted image should be here but it was not working when we last tested it.
dunno John - I'm not a good builder plus am about dead energy-wise for all practical purposes - as a cop-out it might first go o an open baffle above my Gw-1858 H-frame woofer instead of the D216 I'm using - - here's an idea by GregB - - GM simulated it with two different circular vents - maybe he can put up the spl and Z-in plots
direct link http://img57.imageshack.us/img57/6720/betsy.png
An externally hosted image should be here but it was not working when we last tested it.
direct link http://img57.imageshack.us/img57/6720/betsy.png
FWIW i played one driver in its shipping box and without a box with YouTube videos for a few minutes including Flight Of The Bumblebee on 7-string bass to exercise its suspension - vocal quality seems very good - if (?) my WT3 is calibrated ok with a 1K wiresound resistor then Qms is very low - this is without much break-in - I'm not sure if the Vas figure from added mass method can be trusted http://img134.imageshack.us/img134/2995/bk1ts1.gif
freddi said:
Top plot is based on the assumption that the K-slot's acoustic center (mean) can be calculated same as an exponential horn's, which places it almost at the closed end of the slot, hence the higher tuning. The 'alternate' assumes the port is near/at the bottom. Note that the port is simmed as a ~6" dia. (28"^2) x 0.75" hole, so in reality the roll off response is probably somewhere in between the two.
GM
Attachments
my old pc is kinda quirky on WT3 but here's another TS run after lotsa of bass tracks for BetsyK and for comparison a new Panasonic"Metal" which is quite a bit more massive for magnet bulk and double the Burro driver's cost. When running online bass tests from YouTube of BetsyK and no cabinet and listening up very close , it was clean with regards to no weird overtones on tracks swooping down to below 5Hz which is more than I could say for some larger vintage drivers
did anyone else measure BetsyK? how do my twoTS runs result look for GregB's cabinet? Vas seems very tricky to get with added mass method - when I added more mass than 7 gram to BetsyK, mms went up beyond resons
BetsyK TS after more excursion work - she didn't go down from the first run - In a vented MLTL there sure wouldn't be much z variation
new Panasonic "Metal"
did anyone else measure BetsyK? how do my twoTS runs result look for GregB's cabinet? Vas seems very tricky to get with added mass method - when I added more mass than 7 gram to BetsyK, mms went up beyond resons
BetsyK TS after more excursion work - she didn't go down from the first run - In a vented MLTL there sure wouldn't be much z variation
An externally hosted image should be here but it was not working when we last tested it.
new Panasonic "Metal"
An externally hosted image should be here but it was not working when we last tested it.
Greets!
You're welcome!
The sim is 0.2 lbs/ft^3 of polyfil spread evenly throughout the whole cab or ~ 9.25 oz total, but FWIW I prefer to just line one of each pair of parallel walls with 1" acoustic fiberglass insulation and any additional added only at the top. Probably a better choice considering the K-slot.
GM
You're welcome!
The sim is 0.2 lbs/ft^3 of polyfil spread evenly throughout the whole cab or ~ 9.25 oz total, but FWIW I prefer to just line one of each pair of parallel walls with 1" acoustic fiberglass insulation and any additional added only at the top. Probably a better choice considering the K-slot.
GM
Listenning impressions with the Betsy (OB version) are pretty good. I have plenty of fiddling and tweaking to do with the driver and the baffle, but so far I am pleased. I feel potential in there somewhere just waiting to be coaxed out. For instance, the clarity or definition in the bass region is good, but not outstanding as I've heard other OBs, I will play with the mass of the baffle and mounting of the driver to see if there's a solution. The amount and depth of bass is again good, I will see if I can't take it further as I've been able to do before with series R and baffle tricks. And the highs seem like they go far enough when nearfield and on axis, but maybe not enough when not ideally placed, but there's a hundred tweaks & tricks to try for this. I do have one question in this regard, though. When the shout or edginess is more pronounced off-axis due to diminished highs, what are the tricks? Soften the whizzer, cone coating, fluffy material twixt the cone and whizzer, or what?
In conclusion, good value IMHO. I had these mated with a sub and a tweet crossed very high and it was fantastic. I am working toward a single driver, though. It will come along; this is simply a case where there is nobody out there that can say, "Oh yeah, I've had this driver for years, here are the tweaks". Support this small business guy, he's got a good spot in between the ANs and the Bofu.
One more thing... I haven't measured and I can't recall the manufacturers claim, but these guys are very high sensitivety. I am quite pleased with the amount of output when hooked up to the featherweight T-amp.
In conclusion, good value IMHO. I had these mated with a sub and a tweet crossed very high and it was fantastic. I am working toward a single driver, though. It will come along; this is simply a case where there is nobody out there that can say, "Oh yeah, I've had this driver for years, here are the tweaks". Support this small business guy, he's got a good spot in between the ANs and the Bofu.
One more thing... I haven't measured and I can't recall the manufacturers claim, but these guys are very high sensitivety. I am quite pleased with the amount of output when hooked up to the featherweight T-amp.
What kind of cone treatment are you gearing up for?
As for phase plugs, well, they're gonna be a little tiny. I understand the principle on which they work, but my first reaction is to question how effective such a small plug would be. Or is ther going to be a funky (lightbulb, doorknob type) shape?
With such a small magnet structure, I see less benefit in the epoxy-in-the-gap tweak, although I will do it anyway. Opinions?
Keep us posted (as you often do), Dave, and thanks for all the help and info along the way. You have had a great role in my conversion to fullrangers and driver mods. Hell, while I'm at it, Scottmoose- a whole buch of my freinds think I'm some sort of witch when they hear the different BVRs I make for them. You're a clever guy. You guys go ahead and give each other five bucks.
As for phase plugs, well, they're gonna be a little tiny. I understand the principle on which they work, but my first reaction is to question how effective such a small plug would be. Or is ther going to be a funky (lightbulb, doorknob type) shape?
With such a small magnet structure, I see less benefit in the epoxy-in-the-gap tweak, although I will do it anyway. Opinions?
Keep us posted (as you often do), Dave, and thanks for all the help and info along the way. You have had a great role in my conversion to fullrangers and driver mods. Hell, while I'm at it, Scottmoose- a whole buch of my freinds think I'm some sort of witch when they hear the different BVRs I make for them. You're a clever guy. You guys go ahead and give each other five bucks.
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