Well, i had cut out the dustcap on the Vifa P13 and I retrieved the audax 10 MM tweeters from the mailbox about 2 hours ago . A few minutes with the dremel and a cutoff disc and they were out of thier "can" mount and are gorgeously tiny. I couldnt wait so i set up 1 p13 bare and crossed a tweeter in beside it with a 3 UF cap, at about 6 KH and replaced one of the Jordan JX92s with it. Fired it up and have been listening for coupla hours . Right away , too hot on the top. So I went to a 2.2 UF, about 9KH. BETTER!, but still too hot. Of course without an enclosure of any kind the ballance is skewed to the top BUT this thing shows incredible potential!
The little tweeter is FAB! Sweet and pure even tho too hot! Now I need HELP
Where do i find info on how to pad down the tweet by 2 and then 4 DB? Its 8 ohm. I want to use a fixed L pad of high quality resistors then play with caps some more . Miked @ 3 ' its +- 1, maybe 2 Db, 500 to 16 k. And its not coaxial yet. I am overly sensitive to flat responce in the trebble and want to roll it off a little. I am STOKED! Tomorrow ill see if I can get one mounted coaxially, as near field (43") I can hear the center shift around side to side as freq changes. Im amazed this took me 4 years to try, thats how long ive had the p13s sitting around. This thing might end up as good or better than the Jordans The cap is an AXON foil.
I love the look of the 24 carat gold dome mad had the tweets for 12.95.
Its 2 AM and i cant tear myself away I will keep you posted
The little tweeter is FAB! Sweet and pure even tho too hot! Now I need HELP
Where do i find info on how to pad down the tweet by 2 and then 4 DB? Its 8 ohm. I want to use a fixed L pad of high quality resistors then play with caps some more . Miked @ 3 ' its +- 1, maybe 2 Db, 500 to 16 k. And its not coaxial yet. I am overly sensitive to flat responce in the trebble and want to roll it off a little. I am STOKED! Tomorrow ill see if I can get one mounted coaxially, as near field (43") I can hear the center shift around side to side as freq changes. Im amazed this took me 4 years to try, thats how long ive had the p13s sitting around. This thing might end up as good or better than the Jordans The cap is an AXON foil.I love the look of the 24 carat gold dome
mad had the tweets for 12.95.Its 2 AM and i cant tear myself away
I will keep you posted
crossovers
hey gm,
i've been designing crossovers using this applet and have a few questions.
heres the setup...altec 806/811,jbl le5, electrovoice evm15l (le5 is in an edgar 300 mid horn now)
http://uk.f2.pg.photos.yahoo.com/ph...ttp://uk.f2.pg.photos.yahoo.com/ph//my_photos
its crossed at 500hz and 5khz 1st order... i like the purity of first order and p.r.a.t is also important to me but i want to roll the woofer off quicker as it contributes too much to the midrange at present.......as 4th order intruduces no phase shift ( zero degrees) is it compatable with a first order mid/treble
furthermore could i add a jbl 2405 crossed 4th order and still keep a first order mid.
sorry if this sounds stupid..as far as crossover design goes i am an electro-acoustic numpty
many thanks
gary mcdonnell-thomas
p.s heres another calculator http://ccs.exl.info/calc_cr.html#first
hey gm,
i've been designing crossovers using this applet and have a few questions.
heres the setup...altec 806/811,jbl le5, electrovoice evm15l (le5 is in an edgar 300 mid horn now)
http://uk.f2.pg.photos.yahoo.com/ph...ttp://uk.f2.pg.photos.yahoo.com/ph//my_photos
its crossed at 500hz and 5khz 1st order... i like the purity of first order and p.r.a.t is also important to me but i want to roll the woofer off quicker as it contributes too much to the midrange at present.......as 4th order intruduces no phase shift ( zero degrees) is it compatable with a first order mid/treble
furthermore could i add a jbl 2405 crossed 4th order and still keep a first order mid.
sorry if this sounds stupid..as far as crossover design goes i am an electro-acoustic numpty
many thanks
gary mcdonnell-thomas
p.s heres another calculator http://ccs.exl.info/calc_cr.html#first
update on the update
SUCKSESS! I have 1 of "THORS TACKHAMMERS" finished. i
superglued a magnet to the rear of the micro tweeter. the
pole piece is down in the voice coil former so far, i needed
something to space it out. Then i just stuck the mag to the
pole piece . Works perfectly so now im listening to a coax
finally! . I was concerned that removeing the dust cap would
affect the freq res of the p13, but it didnt faze it! Am back
to a 3UF cap wide open and its sounding SPLENDID. Im
astonished at how easy this was but i DID start with 2
GREAT drivers . The integration thru the XO seems FLAWLESS!
IT dosent sound like a coax ! It sounds like a good FR unit!
Now i have to get it in an enclosure of some kind . I have an
unused pair of the little Nohr 3.0 Drums here . HMMM I
could cut the hole bigger(its a 3") and try that. I would have
to make a new Baffle buts thats par I adore the shape of
these little drums and if it works it would be great
Currently there is an FE 85 Fostex in them. Gave the original
tangband away. Didnt like it .
SUCKSESS! I have 1 of "THORS TACKHAMMERS" finished. i
superglued a magnet to the rear of the micro tweeter. the
pole piece is down in the voice coil former so far, i needed
something to space it out. Then i just stuck the mag to the
pole piece . Works perfectly so now im listening to a coax
finally! . I was concerned that removeing the dust cap would
affect the freq res of the p13, but it didnt faze it! Am back
to a 3UF cap wide open and its sounding SPLENDID. Im
astonished at how easy this was but i DID start with 2
GREAT drivers . The integration thru the XO seems FLAWLESS!
IT dosent sound like a coax ! It sounds like a good FR unit!
Now i have to get it in an enclosure of some kind . I have an
unused pair of the little Nohr 3.0 Drums here . HMMM I
could cut the hole bigger(its a 3") and try that. I would have
to make a new Baffle buts thats par
I adore the shape ofthese little drums and if it works it would be great
Currently there is an FE 85 Fostex in them. Gave the original
tangband away. Didnt like it .
Re: update on the update
Sounds like a project I'm working on.......or so I'm told
BTW Gazzamongo, I have that exact same bookshelf from IKEA, same grey color too. I use it for media though.
THOR said:I have an
unused pair of the little Nohr 3.0 Drums here . HMMM I
could cut the hole bigger(its a 3") and try that. I would have
to make a new Baffle buts thats par
these little drums and if it works it would be great
Sounds like a project I'm working on.......or so I'm told
BTW Gazzamongo, I have that exact same bookshelf from IKEA, same grey color too. I use it for media though.
Re: hybrid four door
Baby nOrh's
THOR said:please share ur project with us
Baby nOrh's
A good idea?
That's a crazy idea you've got there Variac.
Although I was thinking, wouldn't the bass ouput of the 15" colour the sound of the midrange significantly?
As it would go straight through the mid rangers cone, unless the back wave was sealed in some how, but then a enclosed mid range might pose a problem, due to the bulkyness of the enclosure.
Any ideas?
That's a crazy idea you've got there Variac.
Although I was thinking, wouldn't the bass ouput of the 15" colour the sound of the midrange significantly?
As it would go straight through the mid rangers cone, unless the back wave was sealed in some how, but then a enclosed mid range might pose a problem, due to the bulkyness of the enclosure.
Any ideas?
Well....yes! Peerless had/has some midrange cones that came with a housing attached, so it would be similar. The mid would have to have an enclosure of some sort maybe made of PVC pipe maybe custom to fit the correct diameter. It would stick out from the 15" like a phase plug, or a cooling phase plug as some of the Eton speakers have. it might color the sound, but who knows maybe for the best! especially if it was straight. 4" drivers seem to have 4-1/2" frames so it might have to flare a bit, but a true cone midrange- not bass/mid, doesn't need much enclosure volume. Any good driver ideas?
Re: crossovers
Greets!
Uh, 4th order has 360 degs of phase shift, i.e. a 1.0Hz offset, so ideally only a 2nd (wired in opposite polarity) or 4th order should be used with it if the acoustic centers are aligned. Also, there's no real 1st order 'purity' unless you've used whatever EQ is required to flatten the response and offset the acoustic roll-offs. That said, if passives are used, then the fewer components of a textbook 1st order has some worthwhile sonic gains if certain conditions are met, with series being preferred over parallel.
Note that any XO formulas/calculators assumes a time aligned, resistive load so results tend to be dramatically different than predicted. As for sounding 'stupid', I reserve that to describe folks who for whatever reason ask the same question repeatedly.
Anyway, not knowing the response of the Edgar horn or of the summed system in-room response I can't even guess as to what the actual LF/mid and mid/HF acoustic roll offs are, so about all I can say is try it.
GM
gazzamongo said:
Greets!
Uh, 4th order has 360 degs of phase shift, i.e. a 1.0Hz offset, so ideally only a 2nd (wired in opposite polarity) or 4th order should be used with it if the acoustic centers are aligned. Also, there's no real 1st order 'purity' unless you've used whatever EQ is required to flatten the response and offset the acoustic roll-offs. That said, if passives are used, then the fewer components of a textbook 1st order has some worthwhile sonic gains if certain conditions are met, with series being preferred over parallel.
Note that any XO formulas/calculators assumes a time aligned, resistive load so results tend to be dramatically different than predicted. As for sounding 'stupid', I reserve that to describe folks who for whatever reason ask the same question repeatedly.
Anyway, not knowing the response of the Edgar horn or of the summed system in-room response I can't even guess as to what the actual LF/mid and mid/HF acoustic roll offs are, so about all I can say is try it.
GM
Variac said:
Hmm, a 15"/4" VC is good for ~1079Hz as a piston, so assuming a 1st order XO, -24dB = ~67.44Hz. So much for making an apparent 'fullrange' driver.
Next best is 4th order, or ~539.5Hz, so any XO point < this should work fine. The Fostex FF85K (ideally with the mounting plate ground down) looks like a good candidate at this XO point/slope and is small enough to comfortably fit inside a 4" VC. Also, adding a super tweeter may be a waste of time/$$ if the published plot is ~accurate.GM
Variac said:Well....yes! Peerless had/has some midrange cones that came with a housing attached, so it would be similar. The mid would have to have an enclosure of some sort maybe made of PVC pipe maybe custom to fit the correct diameter. It would stick out from the 15" like a phase plug, or a cooling phase plug as some of the Eton speakers have. it might color the sound, but who knows maybe for the best! especially if it was straight. 4" drivers seem to have 4-1/2" frames so it might have to flare a bit, but a true cone midrange- not bass/mid, doesn't need much enclosure volume. Any good driver ideas?
That sounds like quite a good idea, using a PVC pipe that is attached to the pole piece would increase the volume of the mid range enclosure, with a bit of stuffing it hopefully won't sound too coloured at all. That new tangband looks like a good 'un, the one someone modified with a ring of glue.
GM said:
Hmm, a 15"/4" VC is good for ~1079Hz as a piston, so assuming a 1st order XO, -24dB = ~67.44Hz. So much for making an apparent 'fullrange' driver.
GM
You couldn't water this down somewhat for me GM, as I'm a newbie here and I'm kinda baffled by this explanation. TBH I was thinking a XO much lower than 1khz, probably somewhere around 200-500hz, in a bit of a less sensitive range.
Hybrid fourdoor said:
I suppose you could put some screws at either end of the PVC phase plug, that way both magnets would be attracted to the screws, hopefully enough to counteract the effect on the magnets on each other.
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