You might be inspired by the following web site: German Physiks
As mentioned by Graaf in the thread he links to, the positioning of any omnidirectional speaker is crucial unless you have such a large room that allows you to have the speakers at least 1,7m (5,7 foot) away from the closest wall.
Did Magnetar build something? He has not been posting here for a while...
Regards,
Etienne
As mentioned by Graaf in the thread he links to, the positioning of any omnidirectional speaker is crucial unless you have such a large room that allows you to have the speakers at least 1,7m (5,7 foot) away from the closest wall.
Did Magnetar build something? He has not been posting here for a while...
Regards,
Etienne
mattIlikesound said:
Unless used as something like a nearfield computer monitor it really could use a high pass on it (althou i have for the last week been happily running a pair of unassisted µFonken in my living room.
Using multiple in a line array would spoil what they do well... we will be trying a pair in a set of Frugel-horns (1 driver firing sideways as in Cal's Calhouns)
Think of the FF85k as a 3/4" tweeter with a very large surround that lets you XO them very low.
dave
I started to work on omni speaker too. some of you are using sonotubes for enclosure. I tried it yesterday. pipe resonance causes extremely rippled response, multiple peaks in impedance curve, plus distortion is MUCH higher then one measured free air. stuffing alone can't defeat those ripples there must be some kind of diffuser on the bottom or tube. maybe something like in attached picture.
Attachments
MisterTwister,
You might found the following patent of interest: link
The abstract is in English but the rest is in French. The same principle is used in the LS from Venus Acoustic in order to supress most of the problems caused by back waves. The bass reflex port shown on the pictures can be removed, but the pyramid (or the cone) marked 7 on the picture must be there according to the invention.
Regards,
Etienne
You might found the following patent of interest: link
The abstract is in English but the rest is in French. The same principle is used in the LS from Venus Acoustic in order to supress most of the problems caused by back waves. The bass reflex port shown on the pictures can be removed, but the pyramid (or the cone) marked 7 on the picture must be there according to the invention.
Regards,
Etienne
MisterTwister,
with a vertical tapered divider you could make the tube into a mass loaded TML. If you close one half of the line early you manage to place the driver at 2/3 of the line. That way you can control pipe resonances much better than by stuffing or diffusers only.
with a vertical tapered divider you could make the tube into a mass loaded TML. If you close one half of the line early you manage to place the driver at 2/3 of the line. That way you can control pipe resonances much better than by stuffing or diffusers only.
Rudolf, TL probably is the best way to do it, but it's too complicated for me, I'm just not ready to put so much effort into these particular speakers.
I'll just do a few experimentations with diffusors and stuffing, and choose one that works best.
I'll just do a few experimentations with diffusors and stuffing, and choose one that works best.
why not use a coaxial speaker
hi
I tried the same concept like AJ but with a 6½" coaxial car speaker from Monacor (cheap ones).
This way you only need one reflector. I don´t know if it qualifies for a one point source?
The reflector I used was a cone made out from a 4 - 5" solid aluminium cylinder.
I wanted to do the same concept but on a larger scale with a 12" coaxial from radiant audio and a 18" beyma G550 but th radiants where too expensive for me at that time. Still have the beyma though and might give it a shot in a year or two from now.
I kind of liked the sound. It is very open and there is a really big sweetspot. Even with the cheap car speakers (with one of the woofers voice coils scratching already at modest levels ).
If I can find a picture of them when I get home from work I will post it.
uwe
hi
I tried the same concept like AJ but with a 6½" coaxial car speaker from Monacor (cheap ones).
This way you only need one reflector. I don´t know if it qualifies for a one point source?
The reflector I used was a cone made out from a 4 - 5" solid aluminium cylinder.
I wanted to do the same concept but on a larger scale with a 12" coaxial from radiant audio and a 18" beyma G550 but th radiants where too expensive for me at that time. Still have the beyma though and might give it a shot in a year or two from now.
I kind of liked the sound. It is very open and there is a really big sweetspot. Even with the cheap car speakers (with one of the woofers voice coils scratching already at modest levels ).
If I can find a picture of them when I get home from work I will post it.
uwe
MisterTwister said:
What was the length of the sonotube you where using? What your crossover point?
Note that length of tube "should" be more than a quarter wavelength...
Matej
mattIlikesound said:
Here are a some links to few hybrid omni projects I have designed and built and some photos of them. They all use a direct firing tweeter, not an omni tweeter. the latter two are complete except are still in the finishing stage (veneer, paint, etc.)
http://htguide.com/forum/showthread.php4?t=26065&highlight=omnidirectional
http://htguide.com/forum/showthread.php4?t=28906&highlight=Soundrounds
http://htguide.com/forum/showthread.php4?t=29620
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
matejS, quater wavelength of what frequency?
tube length is 33in, woofer is seas h511, tweeter is dayton nd28f-8 I don't know crossover frequency yet, maybe I let this woofer run full range, it's nice poly cone without break-up and listening axis is 90' and I'm making enclosure sealed.
maybe it's not a real omni speaker though, see attached.
tube length is 33in, woofer is seas h511, tweeter is dayton nd28f-8 I don't know crossover frequency yet, maybe I let this woofer run full range, it's nice poly cone without break-up and listening axis is 90' and I'm making enclosure sealed.
maybe it's not a real omni speaker though, see attached.
Attachments
MisterTwister said:
resonant f = c / 4L
f = cca 100Hz
Your tube will resonate at around 100Hz. I would make tube a little but longer and set crossover point at 100Hz (or increase crossover point). Like Linkwitz did - see http://www.linkwitzlab.com/Pluto/construction.htm
Yes, you will loose LF - that's life 🙁
If you will try it, let me know how it works...
EDIT: oh, another thing, did you calculate directivity of the speaker? 6" speaker it will radiate "omni-directional" up to cca 1000Hz (to be perfect to a little less than 500Hz, but 1000Hz is acceptible, i.e. ka=2). Larger speaker (piston diameter) speaker is less omni-directional. I guess you've noticed lower sound level of high frequencies, right? 😉
Cheers,
Matej
matejS, thanks for your comments. actually I want them to play full range (down to 50 hz)
I'll just make diffusers, so inside volume is no longer a tube shape.
I'll just make diffusers, so inside volume is no longer a tube shape.
I am thinking of making something similar to the Bolzano Villetri Torre.
Has anyone every heard these? Any suggestions on components and tweeters?
http://www.bolzanovilletri.com/
I was thinking of using a pair of Silver Flute 8" Wool cones and then a set of Hi-Vi tweets, but I am not sure about the reflected sound from the tweeters. I am also considering putting the tweets on the side of the cabinet or even on two sides of the cabinet, but reflections kind of scare me.
What do you guys think?
Robert
Has anyone every heard these? Any suggestions on components and tweeters?
http://www.bolzanovilletri.com/
An externally hosted image should be here but it was not working when we last tested it.
I was thinking of using a pair of Silver Flute 8" Wool cones and then a set of Hi-Vi tweets, but I am not sure about the reflected sound from the tweeters. I am also considering putting the tweets on the side of the cabinet or even on two sides of the cabinet, but reflections kind of scare me.
What do you guys think?
Robert
SL stuffs the Pluto tube, creating a damped transmission line with a 40dB return loss. It works great down to 60Hz in the original Pluto at limited SPL; Pluto 2 with the higher displacement Seas driver gets the bottom end lifted with a Linkwitz Transform for F3=40Hz, Q=.7.
impedance peaks were tamed with dence stuffing.
one peak at ~170hz still there. SL did not completely defeat pipe resonances in "Pluto" either.
one peak at ~170hz still there. SL did not completely defeat pipe resonances in "Pluto" either.
An externally hosted image should be here but it was not working when we last tested it.
This might be a completely irrelevant question, but is there any place using omnis as surround speakers? I was thinking of using perhaps a full range driver in an omnidirectional setup for the two rear surrounds to better "spread" the effect. Would this be a possibility?
From what ive seen in most of these a cone or sphere shape is used to reflect the sound.
And the ones complaining about stereo are using two speaker cabinets.
What about two back to back 180 degree reflectors or a 360 with divinging panels. then instead of having one speaker under it have two form a V with the deflector and divider in the middle of them. then place it on top of your tv maybe... just an idea.
And the ones complaining about stereo are using two speaker cabinets.
What about two back to back 180 degree reflectors or a 360 with divinging panels. then instead of having one speaker under it have two form a V with the deflector and divider in the middle of them. then place it on top of your tv maybe... just an idea.
slot loading omni vs. simple deflectors
FWIW, one of the most "successful" omni designs was made by JBL, who used pressurized slot deflectors over its drivers instead of simple deflectors. in short, there was a bit of engineering in these.
problem was the engineering was done before computers were readily available and the development cost became quickly prohibitive. i owned 2 pair of this series and can tell you they each had their merits.
not trying to sell the Aquarius line here, but the Aquarius I was quite something to behold in spite of the mis-tuning of the port. basically it was the L-100 repackaged (before L100 was introduced) with deflectors over the LE10A woofer and the LE5 midrange units.
the Aquarius II was similar but with rear-firing woofers and midrange and never really made production.
the Aquarius IV was the most popular.
the point is pressurizing the drivers with the lenses. i think it makes all the difference in the sound. and it seems no one else is doing this?
for more on AQUARIUS
FWIW, one of the most "successful" omni designs was made by JBL, who used pressurized slot deflectors over its drivers instead of simple deflectors. in short, there was a bit of engineering in these.
problem was the engineering was done before computers were readily available and the development cost became quickly prohibitive. i owned 2 pair of this series and can tell you they each had their merits.
not trying to sell the Aquarius line here, but the Aquarius I was quite something to behold in spite of the mis-tuning of the port. basically it was the L-100 repackaged (before L100 was introduced) with deflectors over the LE10A woofer and the LE5 midrange units.
the Aquarius II was similar but with rear-firing woofers and midrange and never really made production.
the Aquarius IV was the most popular.
the point is pressurizing the drivers with the lenses. i think it makes all the difference in the sound. and it seems no one else is doing this?
for more on AQUARIUS
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