If that driver cost more than $25 I would have to agree with you. By the time the foam starts to degrade (years) I will have already moved on to bigger and better things I'm sure.
I was merely looking for a low cost alternative to the $600 worth of DPL-12's that will hopefully be the "bigger and better" thing I move on to some day (putting pennies in a jar as I speak 😉) .
MEXXX
"I was merely looking for a low cost alternative to the $600 worth of DPL-12's"
Ok I already posted about the madison drivers.. and I still think you would be better off with the Knight 15's but..
here is another gift (for those surfing the extreme side of cheap DIY):
http://www.dynavox.com/
click on "12in" under the woofers heading.
now take a gander at:
SW-1220FL and the WP-1220
The aluminum version looks a bit like the gilmore audio drivers (but isn't). No doubt the poor coil, pole-piece, and venting of these cheap drivers increases distortion - BUT with multiples your reducing distortion. and again you'll need to use a dampening compound on the cheap basket, perhaps red devil's version of temp coat.
also note the price on the madison warrior 15 (cheap version of the Knights)..
http://store.steelsound.com/Detail.bok?no=552
and again the specs are here:
http://madisonspeakers.netfirms.com/rawdrivers.htm
Ok I already posted about the madison drivers.. and I still think you would be better off with the Knight 15's but..
here is another gift (for those surfing the extreme side of cheap DIY):
http://www.dynavox.com/
click on "12in" under the woofers heading.
now take a gander at:
SW-1220FL and the WP-1220
The aluminum version looks a bit like the gilmore audio drivers (but isn't). No doubt the poor coil, pole-piece, and venting of these cheap drivers increases distortion - BUT with multiples your reducing distortion. and again you'll need to use a dampening compound on the cheap basket, perhaps red devil's version of temp coat.
also note the price on the madison warrior 15 (cheap version of the Knights)..
http://store.steelsound.com/Detail.bok?no=552
and again the specs are here:
http://madisonspeakers.netfirms.com/rawdrivers.htm
I want to stick with 4 12's and not 15's do to size. There's only 2 12" drivers at dynavox with 12.7mm Xmax and the rest have 3.5mm. The ones with the 12.7mm Xmax have a Qts of 2.0 and 2.893 . With a Qts that high I'm sure you would get plenty of bass out of a dipole, but I'm not sure how good it would sound.
Hey Scott,
Thanks for that Dynavox link. I had my eye on those very drivers (SW-1220FL) a couple years ago, back when the company was called Orevox. Then they changed their name, my link went dead, and I lost track.
Have you ever inquired about prices?
MEXXX,
Don't be overly concerned with the high Qts of many Dipole drivers. In an OB, you'd be surprised how tight a high-Q driver can sound. Try some sometime and judge for yourself.
Cheers,
Bill
Thanks for that Dynavox link. I had my eye on those very drivers (SW-1220FL) a couple years ago, back when the company was called Orevox. Then they changed their name, my link went dead, and I lost track.
Have you ever inquired about prices?
MEXXX,
Don't be overly concerned with the high Qts of many Dipole drivers. In an OB, you'd be surprised how tight a high-Q driver can sound. Try some sometime and judge for yourself.
Cheers,
Bill
MEXX:
the drivers I specifically mentioned do indeed have 12.5 mm of x-max - in fact they are specifically made for "dipole" use. (Use to be under the "TrueTone" brand I believe..)
As far as quality is concerned.. I think that with an fs as low as they both are that 2+ of Qts is about right for acoustic gain to offset dipole cancelation. This of course only references freq. response, OTHER factors (such as distortion) are probably quite poor - but again.. you'll reduce this to some extent simply by using several drivers.
Bill:
Your Welcome! (yup the co. has changed names, and is generally not something you will find with any common google search..) I'm pretty sure the price of the High Q woofers is around 25 US each. (no doubt they cost 3 bucks to produce in china..)
To All:
ALL the other drivers (other than the dynavox High Q drivers) mentioned in this thread so far are NOT specifically made for (ACOUSTIC) dipole use (though this doesn't invalidate their use by any means).
Common (acoustic) dipole driver discriptors are "High Q", "Open Back", and "Free Air" (though free air drivers are usually dipole drivers loaded in small spaces - i.e. cars).
In addition to the Dynavox woofers mentioned, Eminence makes some dipole woofers. They are under the "Open Back" back moniker. In fact there are several manufactures of "Open Back" drivers - most of which are GUITAR SPEAKER manufacturers (i.e. Jensen, Celestion, etc.). The thing is though that these are High Eff. drivers with VERY limited bandwidth for bass applications.
NOTE: these "Open Back" drivers can be VERY usefull despite their apparent limitations. As Bill has mentioned previously (and can be seen in Chop's freq. response tailoring), typically higher Q normal drivers have a low fs. The Q increases nearing fs and this is where you get your freq. response lift (or compensating acoustic eq.). However the next adjacent octave above these driver's fs will typically NOT have enough "lift". As far as bass freq. response goes, this is the area that is the MOST important (i.e. 50 Hz to 300 Hz), otherwise bass/lower midrange will sound weak. Good open back drivers will typically have a usable response to 70 Hz for compensating in this region. The better drivers have bigger magnets and voice coils which allow for considerably less distortion.
EX.
Consider the Eminence "Big Ben":
http://editweb.iglou.com/eminence/eminence/pages/products02/redcoat/bigben.htm
This driver could easily be combined with a pair of Knight 15's to give a very high eff. (100+ db) dipole configuration that is essentially flat to 35 Hz with NO baffle required. This combination would also have the advantage of quite low distortion within 110 spl levels. (Perhaps pairing with a high eff. fullrange driver or a good pro combination for the rest of the freq. response. - I'd think the McCauley 6326CX 10" coaxial and the BMS 4540 ND would make an EXCELLENT combination..) All thats needed is a bit of creative use of driver orientation to achieve a very low visual signiture for a high eff. design (despite the use of THREE 15 inch drivers per side).
the drivers I specifically mentioned do indeed have 12.5 mm of x-max - in fact they are specifically made for "dipole" use. (Use to be under the "TrueTone" brand I believe..)
As far as quality is concerned.. I think that with an fs as low as they both are that 2+ of Qts is about right for acoustic gain to offset dipole cancelation. This of course only references freq. response, OTHER factors (such as distortion) are probably quite poor - but again.. you'll reduce this to some extent simply by using several drivers.
Bill:
Your Welcome! (yup the co. has changed names, and is generally not something you will find with any common google search..) I'm pretty sure the price of the High Q woofers is around 25 US each. (no doubt they cost 3 bucks to produce in china..)
To All:
ALL the other drivers (other than the dynavox High Q drivers) mentioned in this thread so far are NOT specifically made for (ACOUSTIC) dipole use (though this doesn't invalidate their use by any means).
Common (acoustic) dipole driver discriptors are "High Q", "Open Back", and "Free Air" (though free air drivers are usually dipole drivers loaded in small spaces - i.e. cars).
In addition to the Dynavox woofers mentioned, Eminence makes some dipole woofers. They are under the "Open Back" back moniker. In fact there are several manufactures of "Open Back" drivers - most of which are GUITAR SPEAKER manufacturers (i.e. Jensen, Celestion, etc.). The thing is though that these are High Eff. drivers with VERY limited bandwidth for bass applications.
NOTE: these "Open Back" drivers can be VERY usefull despite their apparent limitations. As Bill has mentioned previously (and can be seen in Chop's freq. response tailoring), typically higher Q normal drivers have a low fs. The Q increases nearing fs and this is where you get your freq. response lift (or compensating acoustic eq.). However the next adjacent octave above these driver's fs will typically NOT have enough "lift". As far as bass freq. response goes, this is the area that is the MOST important (i.e. 50 Hz to 300 Hz), otherwise bass/lower midrange will sound weak. Good open back drivers will typically have a usable response to 70 Hz for compensating in this region. The better drivers have bigger magnets and voice coils which allow for considerably less distortion.
EX.
Consider the Eminence "Big Ben":
http://editweb.iglou.com/eminence/eminence/pages/products02/redcoat/bigben.htm
This driver could easily be combined with a pair of Knight 15's to give a very high eff. (100+ db) dipole configuration that is essentially flat to 35 Hz with NO baffle required. This combination would also have the advantage of quite low distortion within 110 spl levels. (Perhaps pairing with a high eff. fullrange driver or a good pro combination for the rest of the freq. response. - I'd think the McCauley 6326CX 10" coaxial and the BMS 4540 ND would make an EXCELLENT combination..) All thats needed is a bit of creative use of driver orientation to achieve a very low visual signiture for a high eff. design (despite the use of THREE 15 inch drivers per side).
OB + ELF?
I have a pair of EVM12s lying around, and was idly wondering if they would be any good if used below Fs (55Hz).
These are relatively low Q speakers (I forget the numbers),
so would need some sort of EQ.
I suspect they would rapidly run out of power handling capacity at low freqs, but if not used at high vol, an extra octave might be squeezed out of them?
Pete McK
I have a pair of EVM12s lying around, and was idly wondering if they would be any good if used below Fs (55Hz).
These are relatively low Q speakers (I forget the numbers),
so would need some sort of EQ.
I suspect they would rapidly run out of power handling capacity at low freqs, but if not used at high vol, an extra octave might be squeezed out of them?
Pete McK
Apology accepted. For a second, I thought I must have deleted the contents of the post or something. 🙂cytokine said:
Something occured to me in thinking through the utility of a dipole subwoofer like the one chops describes. How high can these go?
I know we have spent a lot of time discussing how low they will play and what kind of wattage it will take to get good SPL, but I need to know how high I can cross something like a W or an H configuration of a pair of the Pyle PPA15s driven by something like the PartsExpress product listed here.
I'm thinking of building one of these (limited budget) and crossing as high as it will go or until it integrates with my line arrays.
I mentioned the line arrays briefly before but to refresh, they are made from the PartsExpress buyout 4" NSB drivers and the Onkyo tweeters. By my calculations they will have exactly no bass. These drivers start rolling off pretty hard at around 200 Hz in an open baffle which is how mine are configured.
Soooo... how high can you go with an open baffle subwoofer?
I know we have spent a lot of time discussing how low they will play and what kind of wattage it will take to get good SPL, but I need to know how high I can cross something like a W or an H configuration of a pair of the Pyle PPA15s driven by something like the PartsExpress product listed here.
I'm thinking of building one of these (limited budget) and crossing as high as it will go or until it integrates with my line arrays.
I mentioned the line arrays briefly before but to refresh, they are made from the PartsExpress buyout 4" NSB drivers and the Onkyo tweeters. By my calculations they will have exactly no bass. These drivers start rolling off pretty hard at around 200 Hz in an open baffle which is how mine are configured.
Soooo... how high can you go with an open baffle subwoofer?
I asked the same question a little while ago, and i think i remember someone saying that a W can play up to 230-270??? Im not quite sure, but im pretty sure its somewhat around that range??? I think that the W is most restricted in how high it can play. I am planning on using a 4th order active XO at 230 to the NSB's from 8 10's i have (per side in a line array), I may end up only using 6 per side due to ceiling heigth.
I use a fullrange on an OB, so the good news is that there's no real upper limit if you do it right.
An OB with one front-to-back path length (for example, a driver centered in a circular baffle--a worst-case scenario) will have a response that climbs to a +6dB peak (a point called Fp) followed by a deep null, then a diminishing series of more peaks and nulls. Fp is a function of baffle width.
If you're planning to run an OB through its Fp, try to create a wide range of front-to-back path lengths. This will spread Fp over a range of frequencies and greatly smooth response. This is why optimized fullrange OBs position the driver off-center, ideally a different distance from every edge, with no two distances having common denominators greater than, say, two.
Now, if you're talking about something like an H or W baffle where you've created partially enclosed spaces in front of and behind the driver, each of those spaces will have a resonant frequency you'll want to avoid, so you won't be able to go as high.
An OB with one front-to-back path length (for example, a driver centered in a circular baffle--a worst-case scenario) will have a response that climbs to a +6dB peak (a point called Fp) followed by a deep null, then a diminishing series of more peaks and nulls. Fp is a function of baffle width.
If you're planning to run an OB through its Fp, try to create a wide range of front-to-back path lengths. This will spread Fp over a range of frequencies and greatly smooth response. This is why optimized fullrange OBs position the driver off-center, ideally a different distance from every edge, with no two distances having common denominators greater than, say, two.
Now, if you're talking about something like an H or W baffle where you've created partially enclosed spaces in front of and behind the driver, each of those spaces will have a resonant frequency you'll want to avoid, so you won't be able to go as high.
Bill F. said:
Regarding the line arrays, yes, that's what I've done. However, I inadvertently ended up with the distance from the top driver to the top of the baffle being exactly the same as the distance from the bottom driver to the floor (both 10"). Regarding the sides I think I'm OK as I started with a 12" wide baffle and mounted the mid line off center and then added tapered wings later that make the effective width ~15" total at the top and ~34" at the bottom. The wings recede from the front baffle at a 45 degree angle.
Regarding the H or W configuration, where can I look for guidelines on how to design this critter so as to avoid problems in the top end with resonant frequencies? I'm guessing I'll need to cross over somewhere around 100 or 120 Hz to integrate with the lines. So how high is too high?
This is all hypothetical of course. If the line arrays sound good and go on semi-permenant display in the living room I will build the subwoofer. If not, I'm not sure how I'm going to get rid of these things. They're seven feet tall.
If you're talking line array, don't worry about getting different top/bottom distances. Each driver in the array creates its own Fp interaction, and since they're strung over a range of verticle distances, the top/bottom Fp is nicely averaged out. 🙂
Back to H/W baffles:
It would be a cut-and-try thing, but you could play with the depths of the front/back cavities so the resonances are half an octave apart, so, for example, front-cavity peaks would be superimposed on rear-cavity nulls... But you could burn through some serious time getting that just right...
Back to H/W baffles:
It would be a cut-and-try thing, but you could play with the depths of the front/back cavities so the resonances are half an octave apart, so, for example, front-cavity peaks would be superimposed on rear-cavity nulls... But you could burn through some serious time getting that just right...
As far as a dipole sub with electronic asistance, this is a recipe for disaster. Excursions awll be crazy and you'll damage the driver. Won't sound too good either. As you go down in frequency, the more it becomes like running the woofer without a baffle. As far as the Adire Parthenon is concerned, you probably can't afford it.
I have to dissagree with this. I've been using a couple of 12' woofers in OB with a separate amp and graphic eq for two years now to suppliment my EV LS-12's in OB. The woofers used are just some old woofers I pulled out of speakers bought at yard sales (old 70's speakers). Bass is the best I've ever had in 35 years of being in this hobby. Admittedly, I rarely listen to music over 90dB, but I've never had a problem with drivers doing bad things at my normal listening levels. I've cranked it up to around 100dB a few times just to play with the system, and it sounded fine. Bass is driven by 240/ch (4 ohm) H-K Citation 16.BAM said:
I've had maybe three DVD rentals that had some very low effects in them that caused a sound that may have been the drivers bottoming out. I turned the volume down a bit (I listen to movies louder then I usually listen to music) and all was well.
The only bass in a home system that I've heard that was clearly better came from some nice horn subs I listened to recently.
http://www.geocities.com/the_hurdy_gurdyman/UpdatedHiFiPage.html
Dave
Hi all
IMHO it's better to use a separate sub if your baffles don't go low enough.
Equalisation is fine if used in moderation,
but not as a way to get deep bass from open baffles, I think.
cheers 😉
IMHO it's better to use a separate sub if your baffles don't go low enough.
Equalisation is fine if used in moderation,
but not as a way to get deep bass from open baffles, I think.
cheers 😉
slowmotion said:
http://www.geocities.com/the_hurdy_gurdyman/Moreupdates.html
Well, I just let the measurements speak for themselves. The first graph on this page was taken just a few days ago with 80dB warble tone measured at the listening chair. The OB's used have the pair of 12" woofers per baffle mentioned above. Bass measures quite flat and very clean down to 30Hz. I don't know why some think this is not a viable way to get good bass. I can only think that they have looked only at specs and theory, not actually listened to OB bass done this way. I've lived with this for two years now and am in no hurry to get anything else. Bass is cleaner and more natural then any BR or sealed speaker I've yet had in my home in over 35 years of listening. I'm a believer in OB bass now days! 😉 BTW, I'm only using the two 12" bass drivers per baffle. The ten inch ones are unhooked due to some foam rot. I've flipped the baffles around so the 12' drivers are on the bottom now.
Dave 🙂
I hear you Dave 😉
I use 2 15" pro speakers per side in 140 x 120 cm open baffles,
and have experimented a lot with different sorts of active eq.
To my ears the baffles sound fine down to about 50Hz , or so,
with minor eq.
If I try to eq them down to say, 30Hz or so, the speakers move,( a lot )
but they also produce a lot of distortion down there when equalized
to be "flat" at 30. Probably depends a lot on your room and music taste , too.
For me it's not enough.
cheers 😉
I use 2 15" pro speakers per side in 140 x 120 cm open baffles,
and have experimented a lot with different sorts of active eq.
To my ears the baffles sound fine down to about 50Hz , or so,
with minor eq.
If I try to eq them down to say, 30Hz or so, the speakers move,( a lot )
but they also produce a lot of distortion down there when equalized
to be "flat" at 30. Probably depends a lot on your room and music taste , too.
For me it's not enough.
cheers 😉
Slowmotion,
Your pro drivers probably have an Fs of 50-55hz, so they won't do well much lower on OB.
Your pro drivers probably have an Fs of 50-55hz, so they won't do well much lower on OB.
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