Moondog55 said:
Which midbass?
And subwoofer-like response is is hardly to achieve on an OB, at least not without a lot of compromises. It'd be very wasteful to try to get good response below 40Hz on a flat open baffle IMO.
Regardless of what woofer you simulated.. of course you weren't going to get a flat 20 Hz response from it. I assumed this went without saying..
tinitus said:
The reason it'd seem to work a lot better than it does is because of the low crossover point you'd have to use with it. The higher you go, the more obvious (worse) it'd get. Likely wouldn't do too well above anything than a subwoofer anyway.
For a smallish IB install, it'd probably do ok, although if I was going to spend all the time planning and making modifications to a section of my house for an IB setup, I don't see why anyone would want to settle for that driver. But I guess people do.
For a smallish flat IB above 150+ Hz (and well below that even), good luck wasting your time/money/power/max spl/xmax/etc with EQ'ing (a driver that's only rated at 81 db/w to begin with).
If you want to go the OB route, use a pair (at the very minimum) of Alpha-15A's per channel, or something with greater output than that if you can find it and don't mind throwing more money away (you're unlikely to find much better for the money for OB down to 40Hz, at least from such a well-known manufacturer with as many resources and info readily available to base decisions on). Then, use real subwoofers below 40-50 Hz.
If you're thinking OB subwoofers with high output down into the teens, good luck with that venture, as it'll never happen..
Tinitus we pay far too much for drivers here; but Australia is a very small market far away from most manufacturers, even China is far away, and the few local producers are not making the sort of driver I want to buy, $US 65 WOW !!! that makes $AUD 120 look like a rip-off but add postage and it is actually quite close, aussie dollar and notamericano peso now 1 for 1.
BHTX see post #94, I modelled the Eminence Beta15 in Tony Gee's program.
I'd be happy with it from 90 up to 250/300 in fact it looked good higher than that (1250/1500 ) but it's not going to give any output for low bass, I've already got enough in that range, what I would like is the next octave and a half down to 25Hz.
I know low bass is expensive, takes up money and real-estate, I' cant save Tony's files and show pix, wrong version of Excell, or I'd show the plots.
I need a decent sub or 4, been playing with the 'Tempest' wired in series for nominal 16 R driver and if my arithmetic is correct, Qts drops to 0.27 and would give a reasonable result in a 55litre box,
OB woofers yes, OB sub/infra woofers, can't afford it space or money wise, but I like to play in my head, what ever route I take it's going to be big, FUN and 4-way ( or 3.5-way maybe)
I'd be happy with it from 90 up to 250/300 in fact it looked good higher than that (1250/1500 ) but it's not going to give any output for low bass, I've already got enough in that range, what I would like is the next octave and a half down to 25Hz.
I know low bass is expensive, takes up money and real-estate, I' cant save Tony's files and show pix, wrong version of Excell, or I'd show the plots.
I need a decent sub or 4, been playing with the 'Tempest' wired in series for nominal 16 R driver and if my arithmetic is correct, Qts drops to 0.27 and would give a reasonable result in a 55litre box,
OB woofers yes, OB sub/infra woofers, can't afford it space or money wise, but I like to play in my head, what ever route I take it's going to be big, FUN and 4-way ( or 3.5-way maybe)
I somehow doubt that. Been trying to hint that to you since the beginning. I'll stop now. You do seem to be going back and forth though.Moondog55 said:
See here: http://www.billfitzmaurice.com/THT.htmlMoondog55 said:
Tempest, eh? See here: http://www.billfitzmaurice.com/THT.htmlMoondog55 said:
Doesn't work that way. BL should double and Re should quadruple, hence the nominal 16 ohm load.Moondog55 said:
Sounds good. See here: http://www.billfitzmaurice.com/THT.htmlMoondog55 said:
But I thought you just implied that you didn't want to mess with anything else except sub bass? Here we are again, going back and forth.Moondog55 said:
Exodus DPL-10 vs Alpha-15A comparison.
DPL-10 on 24"x24" baffle mounted near the floor..
edit: You might need to click the image in your browser to view the original size if you have left your browser options at default, or things might be a little difficult to see. I dunno.. some people forget.
DPL-10 on 24"x24" baffle mounted near the floor..
edit: You might need to click the image in your browser to view the original size if you have left your browser options at default, or things might be a little difficult to see. I dunno.. some people forget.
Attachments
What with the preoccupation with dipoles of late, I'm surprised there's been no attempt to replicate Carver's 'Amazing Speakers' solution to getting near sub LF out of a narrow baffle:
GM
==========
"When it became clear that the original version of the Carver Planar Magnetic
loudspeakers had inadequate woofers, the group that worked on the design
kicked around ideas for improving a weak bass response. They look "at the
formula for the effects of mass and compliance at resonance and thunked
their way to novel solution. The wanted a high-Q resonance at the Fs of the
woofer. They couldn't heft mass up, since that would have all manner of
consequences concerning the speaker motor. They played with the notion of
making the compliance extremely high. They juggled the parameters, and make
the moving mass as light as possible in order to permit making the motor as
small as possible. When the cone moves voice coil and magnet create a
counter voltage, and beefing up the motor bumps up the this bucking
current. So they made the motor small to keep this damping current low. By
making the moving mass as low as possible, they still achieved a reasonable
efficiency. (By quadrupling the woofers and running them in parallel, they
achieved an apparent gain in 16ohm drivers by running them as a 4-ohm quad.
The next issue was how to get extreme compliance without screwing the
pooch. I am not sure if they experimented in house or got a supplier to
make the remedy, but they took three foam roll surrounds and pressed them in
a die. The result is woofer that tests out a Q of 3.0, an amazing figure.
So Carver did build amazing speakers. And you are not likely to duplicate
their results at home. And nobody sells this surround off the shelf. It's
unique, in the real sense of the word. Strictly one-off."
Doug Purl
-----------
"Carver Woofers:
There were three models that I know of that were used in the Amazing
planar woofers, excluding the later 10" Eminence-sourced woofer used in
the AL-III in a vented QB3 enclosure. The prototype woofer was a Sony
model with a foamed cone with foil face. It was a disappointing and
power-hungry performer. Those were followed by house-designed 12" woofers
manufactured in Japan by Tonegen. (BTW, the name comes from the firm
founder a Mr. Tone, a happy coincidence with the English word, but
pronounced as two syllables, toe-nay.)
I have several cartons of the last Carver model, packed six to a box. The
boxes are marked Carver and Made in Japan, but nothing identifying the
maker. The part number is 618-00003-00. This number is also inked on the
woofer magnet, along with K22TNB. My suspicion is that the Oreovox
woofers have been stamped "Carver" by the fellow who puts the prizes in
Cracker Jacks.
Carver Corp. took delivery of the Amazing woofers in batches of a
thousand. When they went under there were almost none left, since they
had been peddling everything cheap but the girls on the line to pay debts,
and even there I think they were conceiving plans. If something found its
way in great numbers to a surplus dealer, it is from a very early model.
The Carver woofer in the mature models is 16 ohms. These are paralleled
to raise the voltage sensitivity from a miserable low 80s dB to
ca. 88-89. The four woofers used in the Platinum series are identical to
the three in the Silver.
Dipole Woofer Parameters: There were comments here complaining about the
skimpy magnets on the Carver woofers. Three wee 1/2" by 2 3/8" wide
circular magnets are stacked to a depth of 1 1/2" to provide for a long
throw (though obviously not the 2" Bob Carver was wont to claim). This is
not a defect but a necessity. One cannot design a high-Qts woofer, such
as a dipole favors, with a powerful, low-Q motor on it. And dipoles are
happiest with a flimsier cone than any other type of woofer loading.
Horn woofers and vented woofers require stiff cones because they work into
a strong acoustic load. Dipoles permit even lightweight film diaphragms
to work because of their low and symmetrical acoustic impedance. One
doesn't connect a diesel truck engine to a motorcycle transmission or a
ship's propeller to an airplane. The notion that bigger is better is an
indication that one does not understand that driver and enclosure form a
system, the parts of which must fit each other suitably, optimally just as
all of us here buy clothes that fit us and not someone else. (I bet I can
leave my size 17 shoes, even new, lying around the bigger/better crowd and
few or none will be tempted to use them; imagine your reaction if the
audio salesman tried to persuade you to buy my shoes -- or mine if they
tried to sell me yours. I bet we all like a good fit. Your woofers
likewise prefer a perfect enclosure fit -- they can get more done with
less effort, just as we can when our shoes fit.)
As for whether the Carver technique of using a very high-Q woofer in
multiples in a dipole works: the Carver Amazing series have a control on
the bass that Bob Carver insisted on marketing as a "Q" adjustment of the
woofer. Inspection of the schematic reveals nothing but a second-order
low-pass filter in the woofer circuit -- a pot, labelled "Q," serving as a
level control. Does the special Carver woofer manage to complement the
dipole cancellation with a natural boost?
Since these discussions started I hooked up my stock pair of Amazing
Platinum IVs. I listened to a number of recordings that permitted
evaluation of bass performance. I must say that in some ways this
combination of planar/film, mid/high, line-source driver and dipole woofer
is frequently disappointing. The problem is that the reproduction is
sufficiently transparent that there is a great variation from recording to
recording in quality. You can hear when one or more recording mikes are
distorting, or when the ambiance is too dry or too wet, or the spectra are
boosted, or bass missing, or the sound is harsh, or artificial, or glassy
or glarey, etc.
Even so, I used some recordings that were outstanding. Every time I have
played the "California Girls" cut on the Telarc "California Project,"
visitors have wanted to buy the speakers. Since I listen primarily to
classical, and own none of the stuff that passes for current popular
music, I found some recordings of film music I thought would provide a
comparative experience acceptable to most of us here. I have several
versions of Bernard Herrmann's music from *North by Northwest*. The
Varese Sarabande (VCD 47205) contains the original orchestral
accompaniment performed by a London pickup orchestra in 1980. (Film
soundtracks get the best of musicians because of the high pay; this
orchestra doubtless contains the cream of the several London symphony
orchestras.) The recording is quite wonderful. The long, climactic Mount
Rushmmore sequence is a kind of concerto for percussion and
orchestra. Lots of bass drum strokes and many, many kettle-drum
shots. The bass drum is deep and taut. No hangover on the Carvers, and
no jukebox boom. Profound is how they sound. And even the kettle drums,
tuned an octave higher, convey a strong impression of a taut skin alive
with harmonic resonances, the same sound one hears in person in a good
hall.
I walked all around my basement while listening to these. My study is
down there: 34' room, concrete walls, finished basement. The same high
quality bass was present throughout a 2000 square foot basement. I cannot
fault any octave the woofers reproduce. No thick ankles, knobby knees,
bulging girdle, spare tire. The very high Q of these woofers seems to do
the trick.
In part I think they are aided by the large tombstone panel they are
mounted on. It creates a mirror image in the floor plane and produces a
different effect than the textbooks predict for a dipole operating in free
space. Suspend the Amazings on cables and I reckon the bass will end
mid-thigh.
Dipole Room Gain:
Several folks here asserted that dipoles "cannot pressurize a room."
Several years back David Moran published a lengthy review (which Bob
Carver reprinted) in the Boston Audio Society Speaker. He listened to BAS
co-founder Alvin Foster's Amazing Platinum IIIs in Foster's basement
listening room. The room is so small that in order to get adequate stereo
separation, Foster had to arrange the speakers with the ribbons on the
outside, swapping left and right speakers. Moran found the bass
overpowering and measured the room-gain effect as producing something like
+8dB at 20 Hz. Moran thought it was bit too much of a good thing.
It is true that the dipole will produce a bit of a bass null along the
plane of the baffle, the product of positive and negative pressure waves
colliding. But once waves pass into the room and meet boundaries, each
boundary becomes a virtual point of wave origin. The oblique waves do not
get the recurrent support that axial waves bouncing between parallel plane
surfaces do. But the ultimate SPL at any given point is the vector sum of
all the waves. The various wave frequencies do not arrive back a the
baffle just in time to receive aid or suppression by a new wave launch.
The analysis done of late on the list presumes the only wave interference
of consequence occurs at the plane of the baffle. But once the waves are
gathered and rebroadcast by the room boundaries, the room phenomena work
just as they do with monopoles. It is only at frequencies where return
waves happen to coincide with initial waves from the driver that secondary
cancellation will be strong. And this will depend on the room dimensions.
And this is the same phenomenon that produces room modes in every bounded
space."
Doug Purl
GM
==========
"When it became clear that the original version of the Carver Planar Magnetic
loudspeakers had inadequate woofers, the group that worked on the design
kicked around ideas for improving a weak bass response. They look "at the
formula for the effects of mass and compliance at resonance and thunked
their way to novel solution. The wanted a high-Q resonance at the Fs of the
woofer. They couldn't heft mass up, since that would have all manner of
consequences concerning the speaker motor. They played with the notion of
making the compliance extremely high. They juggled the parameters, and make
the moving mass as light as possible in order to permit making the motor as
small as possible. When the cone moves voice coil and magnet create a
counter voltage, and beefing up the motor bumps up the this bucking
current. So they made the motor small to keep this damping current low. By
making the moving mass as low as possible, they still achieved a reasonable
efficiency. (By quadrupling the woofers and running them in parallel, they
achieved an apparent gain in 16ohm drivers by running them as a 4-ohm quad.
The next issue was how to get extreme compliance without screwing the
pooch. I am not sure if they experimented in house or got a supplier to
make the remedy, but they took three foam roll surrounds and pressed them in
a die. The result is woofer that tests out a Q of 3.0, an amazing figure.
So Carver did build amazing speakers. And you are not likely to duplicate
their results at home. And nobody sells this surround off the shelf. It's
unique, in the real sense of the word. Strictly one-off."
Doug Purl
-----------
"Carver Woofers:
There were three models that I know of that were used in the Amazing
planar woofers, excluding the later 10" Eminence-sourced woofer used in
the AL-III in a vented QB3 enclosure. The prototype woofer was a Sony
model with a foamed cone with foil face. It was a disappointing and
power-hungry performer. Those were followed by house-designed 12" woofers
manufactured in Japan by Tonegen. (BTW, the name comes from the firm
founder a Mr. Tone, a happy coincidence with the English word, but
pronounced as two syllables, toe-nay.)
I have several cartons of the last Carver model, packed six to a box. The
boxes are marked Carver and Made in Japan, but nothing identifying the
maker. The part number is 618-00003-00. This number is also inked on the
woofer magnet, along with K22TNB. My suspicion is that the Oreovox
woofers have been stamped "Carver" by the fellow who puts the prizes in
Cracker Jacks.
Carver Corp. took delivery of the Amazing woofers in batches of a
thousand. When they went under there were almost none left, since they
had been peddling everything cheap but the girls on the line to pay debts,
and even there I think they were conceiving plans. If something found its
way in great numbers to a surplus dealer, it is from a very early model.
The Carver woofer in the mature models is 16 ohms. These are paralleled
to raise the voltage sensitivity from a miserable low 80s dB to
ca. 88-89. The four woofers used in the Platinum series are identical to
the three in the Silver.
Dipole Woofer Parameters: There were comments here complaining about the
skimpy magnets on the Carver woofers. Three wee 1/2" by 2 3/8" wide
circular magnets are stacked to a depth of 1 1/2" to provide for a long
throw (though obviously not the 2" Bob Carver was wont to claim). This is
not a defect but a necessity. One cannot design a high-Qts woofer, such
as a dipole favors, with a powerful, low-Q motor on it. And dipoles are
happiest with a flimsier cone than any other type of woofer loading.
Horn woofers and vented woofers require stiff cones because they work into
a strong acoustic load. Dipoles permit even lightweight film diaphragms
to work because of their low and symmetrical acoustic impedance. One
doesn't connect a diesel truck engine to a motorcycle transmission or a
ship's propeller to an airplane. The notion that bigger is better is an
indication that one does not understand that driver and enclosure form a
system, the parts of which must fit each other suitably, optimally just as
all of us here buy clothes that fit us and not someone else. (I bet I can
leave my size 17 shoes, even new, lying around the bigger/better crowd and
few or none will be tempted to use them; imagine your reaction if the
audio salesman tried to persuade you to buy my shoes -- or mine if they
tried to sell me yours. I bet we all like a good fit. Your woofers
likewise prefer a perfect enclosure fit -- they can get more done with
less effort, just as we can when our shoes fit.)
As for whether the Carver technique of using a very high-Q woofer in
multiples in a dipole works: the Carver Amazing series have a control on
the bass that Bob Carver insisted on marketing as a "Q" adjustment of the
woofer. Inspection of the schematic reveals nothing but a second-order
low-pass filter in the woofer circuit -- a pot, labelled "Q," serving as a
level control. Does the special Carver woofer manage to complement the
dipole cancellation with a natural boost?
Since these discussions started I hooked up my stock pair of Amazing
Platinum IVs. I listened to a number of recordings that permitted
evaluation of bass performance. I must say that in some ways this
combination of planar/film, mid/high, line-source driver and dipole woofer
is frequently disappointing. The problem is that the reproduction is
sufficiently transparent that there is a great variation from recording to
recording in quality. You can hear when one or more recording mikes are
distorting, or when the ambiance is too dry or too wet, or the spectra are
boosted, or bass missing, or the sound is harsh, or artificial, or glassy
or glarey, etc.
Even so, I used some recordings that were outstanding. Every time I have
played the "California Girls" cut on the Telarc "California Project,"
visitors have wanted to buy the speakers. Since I listen primarily to
classical, and own none of the stuff that passes for current popular
music, I found some recordings of film music I thought would provide a
comparative experience acceptable to most of us here. I have several
versions of Bernard Herrmann's music from *North by Northwest*. The
Varese Sarabande (VCD 47205) contains the original orchestral
accompaniment performed by a London pickup orchestra in 1980. (Film
soundtracks get the best of musicians because of the high pay; this
orchestra doubtless contains the cream of the several London symphony
orchestras.) The recording is quite wonderful. The long, climactic Mount
Rushmmore sequence is a kind of concerto for percussion and
orchestra. Lots of bass drum strokes and many, many kettle-drum
shots. The bass drum is deep and taut. No hangover on the Carvers, and
no jukebox boom. Profound is how they sound. And even the kettle drums,
tuned an octave higher, convey a strong impression of a taut skin alive
with harmonic resonances, the same sound one hears in person in a good
hall.
I walked all around my basement while listening to these. My study is
down there: 34' room, concrete walls, finished basement. The same high
quality bass was present throughout a 2000 square foot basement. I cannot
fault any octave the woofers reproduce. No thick ankles, knobby knees,
bulging girdle, spare tire. The very high Q of these woofers seems to do
the trick.
In part I think they are aided by the large tombstone panel they are
mounted on. It creates a mirror image in the floor plane and produces a
different effect than the textbooks predict for a dipole operating in free
space. Suspend the Amazings on cables and I reckon the bass will end
mid-thigh.
Dipole Room Gain:
Several folks here asserted that dipoles "cannot pressurize a room."
Several years back David Moran published a lengthy review (which Bob
Carver reprinted) in the Boston Audio Society Speaker. He listened to BAS
co-founder Alvin Foster's Amazing Platinum IIIs in Foster's basement
listening room. The room is so small that in order to get adequate stereo
separation, Foster had to arrange the speakers with the ribbons on the
outside, swapping left and right speakers. Moran found the bass
overpowering and measured the room-gain effect as producing something like
+8dB at 20 Hz. Moran thought it was bit too much of a good thing.
It is true that the dipole will produce a bit of a bass null along the
plane of the baffle, the product of positive and negative pressure waves
colliding. But once waves pass into the room and meet boundaries, each
boundary becomes a virtual point of wave origin. The oblique waves do not
get the recurrent support that axial waves bouncing between parallel plane
surfaces do. But the ultimate SPL at any given point is the vector sum of
all the waves. The various wave frequencies do not arrive back a the
baffle just in time to receive aid or suppression by a new wave launch.
The analysis done of late on the list presumes the only wave interference
of consequence occurs at the plane of the baffle. But once the waves are
gathered and rebroadcast by the room boundaries, the room phenomena work
just as they do with monopoles. It is only at frequencies where return
waves happen to coincide with initial waves from the driver that secondary
cancellation will be strong. And this will depend on the room dimensions.
And this is the same phenomenon that produces room modes in every bounded
space."
Doug Purl
tinitus said:
If used on an open baffle of average size that it'd probably be used on, and even a lot larger than average, yes.. there would be a large down hill tilt towards the low frequencies, very similar to what XLBaffle shows.. for the reasons I stated earlier when this woofer was first mentioned.
Nice post GM.
The results portrayed in those texts coincide with my own conclusions made as a result of informal experiments as well, which is good to know.
Obviously, for anyone wondering, the reason the Carver Amazing woofers needed such a high Q (versus a driver like the Alpha-15) was likely because they had a fairly low Fs, since he was trying to obtain low bass response from those relatively narrow flat dipoles.
The downside to that (high Q and low Fs), as mentioned in the text, is a severe loss of sensitivity. Like I said before, trying to obtain low frequency response at reasonable SPL's on OB, say much below 40 Hz, quickly reaches a point of diminishing returns. Qts has to be raised as Fs drops, and sensitivity gets lower and lower. Aside from all that, there aren't any suitable woofers off the shelf for attempting to obtain very low bass on an OB.. as implied in the text GM posted. I've never seen T/S parameters of the Carver Amazing woofers, but I would imagine they must have an Fs anywhere from mid or upper 20's, 30 Hz at most, and perhaps down into the teens. And to obtain a reasonable bass response at frequencies that low on the OB, they ended up with an unheard of Qts of 3. There's not any drivers like that anywhere, at least not that I've seen. There are several cheapo no-name car subwoofers of questionable quality, but their Qts is only near that of the Alpha-15, yet their resonance is down around the 20's.. so they won't work very well, not to mention other characteristics they don't possess to make them ideal for this type of use. For instance, take a look at the cheapo "Goldwood GW-215/8 15" OEM Woofer 8 Ohm" at PartsExpress..
*Power handling: 135 watts RMS/250 watts max *Voice coil diameter: 1-1/2" *Le: .9 mH *Re: 7.1 ohms *Frequency response: 27-1,200 Hz *Magnet weight: 20 oz. *Fs: 29 Hz *SPL: 87.8 dB 1W/1m *Vas: 12.95 cu. ft. *Qms: 7.08 *Qes: 2.69 *Qts: 1.95 *Xmax: 3.5mm *Net weight: 5 lbs.
Price: $28.84 EA (1-3)
Quantity Price: $27.90 EA (4 + )
Fs is indeed a bit lower at 29 Hz, and Qts is very high at nearly 2.0. But for a solid 30Hz on a small flat OB, you better have some decent Xmax, and 3.5mm isn't gonna quite cut it. On top of that, the cone mass is likely WAY too high, and the parts are VERY cheap.
Point is.. I feel that using several Alpha-15A's per channel down to 40Hz, with sub(s) taking over below that.. is the best compromise at this time, and I still plan to try something like this in the near future. My only real complaint as far as the Eminence, is the lack of Xmax. Using multiples will obviously help, but more xmax would certainly be welcomed, and likely put to use.
The results portrayed in those texts coincide with my own conclusions made as a result of informal experiments as well, which is good to know.
Obviously, for anyone wondering, the reason the Carver Amazing woofers needed such a high Q (versus a driver like the Alpha-15) was likely because they had a fairly low Fs, since he was trying to obtain low bass response from those relatively narrow flat dipoles.
The downside to that (high Q and low Fs), as mentioned in the text, is a severe loss of sensitivity. Like I said before, trying to obtain low frequency response at reasonable SPL's on OB, say much below 40 Hz, quickly reaches a point of diminishing returns. Qts has to be raised as Fs drops, and sensitivity gets lower and lower. Aside from all that, there aren't any suitable woofers off the shelf for attempting to obtain very low bass on an OB.. as implied in the text GM posted. I've never seen T/S parameters of the Carver Amazing woofers, but I would imagine they must have an Fs anywhere from mid or upper 20's, 30 Hz at most, and perhaps down into the teens. And to obtain a reasonable bass response at frequencies that low on the OB, they ended up with an unheard of Qts of 3. There's not any drivers like that anywhere, at least not that I've seen. There are several cheapo no-name car subwoofers of questionable quality, but their Qts is only near that of the Alpha-15, yet their resonance is down around the 20's.. so they won't work very well, not to mention other characteristics they don't possess to make them ideal for this type of use. For instance, take a look at the cheapo "Goldwood GW-215/8 15" OEM Woofer 8 Ohm" at PartsExpress..
*Power handling: 135 watts RMS/250 watts max *Voice coil diameter: 1-1/2" *Le: .9 mH *Re: 7.1 ohms *Frequency response: 27-1,200 Hz *Magnet weight: 20 oz. *Fs: 29 Hz *SPL: 87.8 dB 1W/1m *Vas: 12.95 cu. ft. *Qms: 7.08 *Qes: 2.69 *Qts: 1.95 *Xmax: 3.5mm *Net weight: 5 lbs.
Price: $28.84 EA (1-3)
Quantity Price: $27.90 EA (4 + )
Fs is indeed a bit lower at 29 Hz, and Qts is very high at nearly 2.0. But for a solid 30Hz on a small flat OB, you better have some decent Xmax, and 3.5mm isn't gonna quite cut it. On top of that, the cone mass is likely WAY too high, and the parts are VERY cheap.
Point is.. I feel that using several Alpha-15A's per channel down to 40Hz, with sub(s) taking over below that.. is the best compromise at this time, and I still plan to try something like this in the near future. My only real complaint as far as the Eminence, is the lack of Xmax. Using multiples will obviously help, but more xmax would certainly be welcomed, and likely put to use.
BHTX said:
which 15's were these? Have you heard the Hawtorne Augies?
The DPL-10 is a dipole specific driver. Although it's Qts is around 0.8 (the Hawthone 15 Augie Qts is about 0.9 and their 10" Augie has a Qts of less than 0.7) I think it could work well in a baffle with small wings (to extend the bass to about 40Hz).
what the DPL-10 has sacrificed is sensitivity (you will need atleast 2 per channel to make any sense).
I believe that pushing the Qts above 1 might not be desireable.
I'm probably missing mention of it somewhere with this talk of 15" woofers, but are you aware of the newly released DPL-15? Might make for a decent option although I'm likely misreading all this.navin said:
- JP
They were Pyle PPA 15's.. a cheap experiment, wasn't expecting too much in the first place. But I quickly found answers to many of the questions I once had in regards to dipole bass.
I've heard a couple of other dipole setups as well, one of the most recent actually being a pair of Augies on reasonably sized baffles, whose owner I met up with locally a few months ago. He was running them with a plate amp with an internal 4th order crossover, as usual. It seemed ok for what it was, but I kept noticing that the lowpass crossover seemed to be higher than what it was supposedly set to on the plate amp. I pointed this out to him, and we decided to do a bit of investigation. As expected, there was a continuous downhill slope towards the low-end, starting at nearly 200 Hz, resulting in a lack of low frequency response when ran full-range or higher up. As a result, a low crossover point was always used, and more power had to be applied to compensate for the lack of efficiency in the lower frequencies in that range (the lower frequencies that it was actually being used for). So, he ended up with a seemingly higher crossover point to his coaxial mains, with frequencies overlapping. On top of all that, there was also some cancellation taking place from the mains and Augies, but phase adjustment on the plate amp helped relieve this issue somewhat, at least where it was most noticeable. With that said, I believe it's pretty obvious that this is how a large majority of Augie drivers are being used. Not the best way to go about do things, IMO. I'm not saying the drivers are bad at all. The build quality was very good. I'm just saying that with all the ridiculously tiny baffles I've seen some people using these things on, I can't help but wonder how they haven't noticed things not being right, much less satisfied with the result.
WHY??
Why does everyone around here seem to keep forming this opinion? Is it because of decreased sensitivity? As previously mentioned, there's a point of diminishing returns as you try to go lower in frequency with OB. Once you've reached that point, things get tough. As a perfect example, look at all the sacrifices made and struggles encountered with the Carver Amazing. There are ways around the SEVERE sensitivity issue, but only so far around. When you try to go that low with it, it's not going to be extremely sensitive, period.
Or, is it simply because people don't like the thought of choosing to use cheaper woofers with smaller and less powerful motors? If that's the case, the articles GM just posted mentions this. I find that kind of ignorance ridiculous to say the least, and it's rather amusing how everyone tends to follow along with what's generally accepted, even if it's inferior.
There's nothing wrong with a small motor on a woofer used on an OB.. IT'S WHAT WORKS! Why make things more difficult? So you can spend more? Look pretty?? I really don't get it..
I've heard a couple of other dipole setups as well, one of the most recent actually being a pair of Augies on reasonably sized baffles, whose owner I met up with locally a few months ago. He was running them with a plate amp with an internal 4th order crossover, as usual. It seemed ok for what it was, but I kept noticing that the lowpass crossover seemed to be higher than what it was supposedly set to on the plate amp. I pointed this out to him, and we decided to do a bit of investigation. As expected, there was a continuous downhill slope towards the low-end, starting at nearly 200 Hz, resulting in a lack of low frequency response when ran full-range or higher up. As a result, a low crossover point was always used, and more power had to be applied to compensate for the lack of efficiency in the lower frequencies in that range (the lower frequencies that it was actually being used for). So, he ended up with a seemingly higher crossover point to his coaxial mains, with frequencies overlapping. On top of all that, there was also some cancellation taking place from the mains and Augies, but phase adjustment on the plate amp helped relieve this issue somewhat, at least where it was most noticeable. With that said, I believe it's pretty obvious that this is how a large majority of Augie drivers are being used. Not the best way to go about do things, IMO. I'm not saying the drivers are bad at all. The build quality was very good. I'm just saying that with all the ridiculously tiny baffles I've seen some people using these things on, I can't help but wonder how they haven't noticed things not being right, much less satisfied with the result.
WHY??
Why does everyone around here seem to keep forming this opinion? Is it because of decreased sensitivity? As previously mentioned, there's a point of diminishing returns as you try to go lower in frequency with OB. Once you've reached that point, things get tough. As a perfect example, look at all the sacrifices made and struggles encountered with the Carver Amazing. There are ways around the SEVERE sensitivity issue, but only so far around. When you try to go that low with it, it's not going to be extremely sensitive, period.
Or, is it simply because people don't like the thought of choosing to use cheaper woofers with smaller and less powerful motors? If that's the case, the articles GM just posted mentions this. I find that kind of ignorance ridiculous to say the least, and it's rather amusing how everyone tends to follow along with what's generally accepted, even if it's inferior.
There's nothing wrong with a small motor on a woofer used on an OB.. IT'S WHAT WORKS! Why make things more difficult? So you can spend more? Look pretty?? I really don't get it..
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