A member just informed me of a new omni speaker design that looks really simple. Has anyone seen this? Basically a long transparent tube TL with a tapered terminator and the full range omni comes out through the radial basket via backside cone. Uses 3FE25 driver which is quite nice from sensitivity standpoint and very smooth.
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I don't know anything else about it...
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I don't know anything else about it...
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Yah, sort of an upside down Linkwitz LX Mini. But the walls of those clear tubes are so thin they may actually re-radiate some sound in an omni as well.
Yes, the LX mini is but a recent popular take of this theme.
I have builds that go back to early 200s, and those were inspired by Speaker Builder articles a decade earlier.
dave
I have builds that go back to early 200s, and those were inspired by Speaker Builder articles a decade earlier.
dave
How about making the tube walls very thin and resilient, sealing the end, putting the speaker in a sealed box, and................seeing what happens 😎
A couple other points wrt the design of these:
1/ cross-section is likely far to small
2/ somewhat offset by the (likely) overly long pipe
3/ a TL needs to have some method to achieve a lP filter at the terminus. Usually acheived by some or all of, a/ damping. b/ driver offset c/restricted terminus. This pipe looks to have none of these and as such will have significant ripple in the output.
As always with a transparent box, the required damping makes the cosmetic effect much less effective.
dave
1/ cross-section is likely far to small
2/ somewhat offset by the (likely) overly long pipe
3/ a TL needs to have some method to achieve a lP filter at the terminus. Usually acheived by some or all of, a/ damping. b/ driver offset c/restricted terminus. This pipe looks to have none of these and as such will have significant ripple in the output.
As always with a transparent box, the required damping makes the cosmetic effect much less effective.
dave
The terminus has pleats and holes punched along length to provide better impedance matching. This can work somewhat like a Karlson type slot.
An externally hosted image should be here but it was not working when we last tested it.
Those are interesting. Its hard to flex a pipe radially so its not efficient speaker. That flat part at the top might radiate. Flat panels like to vibrate.
Would be interesting to have a pleated wall tube to allow it to flex radially and radiate from the tube and mount the speaker in a sealed box. Not efficient but it would be omni and allow you to test whats coming from the tube.
Would be interesting to have a pleated wall tube to allow it to flex radially and radiate from the tube and mount the speaker in a sealed box. Not efficient but it would be omni and allow you to test whats coming from the tube.
Yes, those MBLs are a cool idea as well. I can't think of a way to create a home brew version of it.
I also built some in the 90's inspired by Speaker builder articles and they sounded good enough that I plan to will revisit that theme at some point. I might even still have some of those articles. Always fun to look back at that stuff.
Hello to all
I'm Claudio Gandolfi I created the 665g project. To make it known, I decided to free use for DIY. The innovation that justifies the filing of the patent is: the emission of secondary waves, attenuated, delayed and consistent with the primary emission of the rear side of the loudspeaker. The effect increases the realism of reproduction.
A brief description of the system follows. The transparent PVC tube carries out the following functions at the same time:
• sound wave guide;
• omnidirectional passive acoustic radiator;
• acoustic delay;
• air container;
• acoustic screen;
• anelastic acoustic energy dissipator;
The lower part of the waveguide is cylindrical and 60 cm long, works as a screen and acoustic delay. The organ-tube shape has the disadvantage of generating resonances. The upper part has an octagonal section and is about 40 cm long and acts as an inelastic dissipating element, attenuating the resonances of the first section.
The air contained in the waveguide with its mass helps to decrease the resonance frequency of the system.
The deformations of the upper octagonal part emit 360 degrees of secondary sound waves, attenuated, delayed and coherent with the primary emission of the rear side of the loudspeaker.
The holes near the high edge of the upper octagonal part and also the upper hole emit by acoustic diffraction further secondary sound waves, attenuated, delayed and coherent with the primary emission of the rear side of the loudspeaker.
I thank you for your interest
I'm Claudio Gandolfi I created the 665g project. To make it known, I decided to free use for DIY. The innovation that justifies the filing of the patent is: the emission of secondary waves, attenuated, delayed and consistent with the primary emission of the rear side of the loudspeaker. The effect increases the realism of reproduction.
A brief description of the system follows. The transparent PVC tube carries out the following functions at the same time:
• sound wave guide;
• omnidirectional passive acoustic radiator;
• acoustic delay;
• air container;
• acoustic screen;
• anelastic acoustic energy dissipator;
The lower part of the waveguide is cylindrical and 60 cm long, works as a screen and acoustic delay. The organ-tube shape has the disadvantage of generating resonances. The upper part has an octagonal section and is about 40 cm long and acts as an inelastic dissipating element, attenuating the resonances of the first section.
The air contained in the waveguide with its mass helps to decrease the resonance frequency of the system.
The deformations of the upper octagonal part emit 360 degrees of secondary sound waves, attenuated, delayed and coherent with the primary emission of the rear side of the loudspeaker.
The holes near the high edge of the upper octagonal part and also the upper hole emit by acoustic diffraction further secondary sound waves, attenuated, delayed and coherent with the primary emission of the rear side of the loudspeaker.
I thank you for your interest
Do you mean back when people just built what they thought would work without the security blanket of simulations?
I started the project in 2013, then I could not imagine that the final aspect would have been this. Over the years I have made dozens of low-cost prototypes with less than 50 euros each. I'm a DIY and I used my technical skills to understand how speakers work and my imagination to think about improvements. Simulation is mandatory when expensive components are used in standard configurations. In non-standard configurations, numerical modeling software is needed for mechanical systems that cost tens of thousands of euros.
The ebook 665g briefly describes the development of the project but only the Italian version exists.
The ebook 665g briefly describes the development of the project but only the Italian version exists.
Claudio, thanks for providing the insight into how your speaker works.
What max sound levels can you get from this design at 1m ?
Which simulation tool did you use for this design? I'm assuming its one of the FEM/BEM suites.
What max sound levels can you get from this design at 1m ?
Which simulation tool did you use for this design? I'm assuming its one of the FEM/BEM suites.
The project name 665g derives from the fact that at the time of writing the ebook the prototype weighed 665 grams. This is a low-cost project that uses a great economic speaker the Faital-Pro 3FE25. The maximum undistorted pressure is about 90 dB, suitable for listening to a workstation or rooms up to 20 square meters. You can increase the volume but quickly increase the distortion for the limited Xmax of the speaker used.
The patented technologies: waveguide acoustic transformer and waveguide acoustic diffractor can be adapted to any type of electrodynamic loudspeaker. Increasing the power increase: quality, costs and weights but there are no theoretical limits. The first part of the waveguide should become stiff and the resonance damping system should be more efficient. In the end, the limits of the system are essentially the limits of the chosen loudspeaker. For those who want to experiment I have a suggestion for a two-way system
diffrattore acustico a guida d'onda waveguide acoustic diffracting device | patents | Pinterest | Acoustic.
The meaning of the previous post was changed by Google translator (my English is still worse). I correct myself. Numerical modeling programs are currently too expensive. In the development of the 665g project it is much cheaper for me to spend 10 euros and redo the PVC or paper waveguide.
The patented technologies: waveguide acoustic transformer and waveguide acoustic diffractor can be adapted to any type of electrodynamic loudspeaker. Increasing the power increase: quality, costs and weights but there are no theoretical limits. The first part of the waveguide should become stiff and the resonance damping system should be more efficient. In the end, the limits of the system are essentially the limits of the chosen loudspeaker. For those who want to experiment I have a suggestion for a two-way system
diffrattore acustico a guida d'onda waveguide acoustic diffracting device | patents | Pinterest | Acoustic.
The meaning of the previous post was changed by Google translator (my English is still worse). I correct myself. Numerical modeling programs are currently too expensive. In the development of the 665g project it is much cheaper for me to spend 10 euros and redo the PVC or paper waveguide.
That's funny, speaker marketing by weight. That would lead to the lightest or heaviest speaker competitions. Your English is fine, I understand it.
If you are interested, you can install ABEC3 (BEM) ABEC3 for free as a "trial". The trial version restriction is you can't save solved model data, so you need to re-run the model each session. ABEC would be able to model this structure but the learning curve is steep.
I am interested in Omni OmniDirectional - work in progress and your speaker got my attention.
Where did you get the thin plastic tubes for the prototypes ?
If you are interested, you can install ABEC3 (BEM) ABEC3 for free as a "trial". The trial version restriction is you can't save solved model data, so you need to re-run the model each session. ABEC would be able to model this structure but the learning curve is steep.
I am interested in Omni OmniDirectional - work in progress and your speaker got my attention.
Where did you get the thin plastic tubes for the prototypes ?
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