EnABL Processes

[Ed LaFontaine]

I think "baffle effects" might mean different things here to different parties.

Baffle effects may include baffle step diffraction that is routinely compensated for in a crossover. Baffle effects also include the intermodulation distortion resulting from reflections off of cabinet & driver edges. Additional effects include the change in speed of sound as it progresses across different materials; ie. Paper, rubber, metal or composites and wood or whatever the baffle is made of.
I don’t think EnABL is represented as totally eliminating baffle step. I think the “disappearing act” Bud refers to is an elimination of some of those things that baffles add to the intended signal.
Until you have heard it (or not), one is unable to respond to the question: “How much is gone?” This question remains until a method is devised to measure things that up to now were not well understood (at least by me).
What does exist is the testimony of users who may not care as much for how it measures.

[soongsc]

Originally posted by Magnetar



Thanks, what box are you talking about and hat pattern did you use to eliminate the baffle effects?

Please see the tests on the JX92S earlier in this thread. Later I also posted two comparisons using a different pattern on a propietary driver, the pattern of which will not be anounced until product release to market. But if you can interpret the data presented on the JX92S, it is easy to see that the spectral decay is improved, although no attempt was made to achieve best pattern for best results. The phase change for test on the JX92S suggests that it will not benefit baffle edge diffraction performance for this particular driver.

[Magnetar]

Originally posted by soongsc

Please see the tests on the JX92S earlier in this thread. Later I also posted two comparisons using a different pattern on a propietary driver, the pattern of which will not be anounced until product release to market. But if you can interpret the data presented on the JX92S, it is easy to see that the spectral decay is improved, although no attempt was made to achieve best pattern for best results. The phase change for test on the JX92S suggests that it will not benefit baffle edge diffraction performance for this particular driver.

Does the boundary layer stay put on the cone when it's operating or does it float in front of or behind the cone?

[soongsc]

Originally posted by Magnetar


Does the boundary layer stay put on the cone when it's operating or does it float in front of or behind the cone?

I don't think there is enough data to make a better judgement on this, but theoretically the pattern is supposed to change a laminar boundary layer to a turbulent boundary layer. How sound waves react to these boundary layers really need finite element type analysis or some other means of test. I have not studied this part yet. Hope someone else does.

By the way, I think there has been other discussion on putting this pattern on speaker enclosures. I have not tried this, and do not plan to do so in the near future until I find some pattern that looks less like a special purpose pattern that combines some artistic flavor compatible with my designs. Theoretically it should work in a similar manner as locating a driver to a location on the baffle that minimizes baffle diffraction effects. That's one of the reasons why many speakers have drivers located at odd locations like my designs.

[Magnetar]

Originally posted by soongsc

I don't think there is enough data to make a better judgement on this, but theoretically the pattern is supposed to change a laminar boundary layer to a turbulent boundary layer. How sound waves react to these boundary layers really need finite element type analysis or some other means of test. I have not studied this part yet. Hope someone else does.

I can't see how the boundary layer can stay stationary with an operating cone.

If that is the case then the transverse waves become longitude waves, as all sound waves appear in air.

[soongsc]

Originally posted by Magnetar


I can't see how the boundary layer can stay stationary with an operating cone.

If that is the case then the transverse waves become longitude waves, as all sound waves appear in air.

Well the transverse waves are the cone vibration. The pattern is to break up the standing waves, and is the main reason for better spectral decay performance.

[Magnetar]

Originally posted by soongsc

Well the transverse waves are the cone vibration. The pattern is to break up the standing waves, and is the main reason for better spectral decay performance.

Hmm - to relate that back to painting the enclosure with a pattern and eliminating baffle effects or for the box to disappear is quite a bit different.

In your cone example you are speaking of energy being stored and released from a moving cone. I believe you are saying there is mechanical energy being released and absorbed with in the cone itself, not the layer of air on the surface of the cone correct?

The box has some energy storage too but I can not see how a couple of microns of paint is going to alter an inch of braced MDF.

[LAL]

Bud,
A few posts back you discussed Enabling a Tangband driver. Regarding the metal phase plug, would the conformal coat cover the entire phase plug or only the areas with the pattern rings?

[Nordic]

The same way a couple of bumps makes sharks swim faster and jets fly faster....

the boundary layer is anywhere there is movement... in fluids (which air is) when you stick your hand out the window while driving... even if you hold it sidewise the boundary layer will drag on it... sure there will also be some "pushing" against the surface area...

[soongsc]

[QUOTE]Originally posted by Magnetar

Originally posted by soongsc

Well the transverse waves are the cone vibration. The pattern is to break up the standing waves, and is the main reason for better spectral decay performance. [/QUOTE

Hmm - to relate that back to painting the enclosure with a pattern and eliminating baffle effects or for the box to disappear is quite a bit different.

In your cone example you are speaking of energy being stored and released from a moving cone. I believe you are saying there is mechanical energy being released and absorbed with in the cone itself, not the layer of air on the surface of the cone correct?

The box has some energy storage too but I can not see how a couple of microns of paint is going to alter an inch of braced MDF.

I do believe they used felt pad on boxes. If you look back through the posts, you will find that the patterns become larger further away from the driver center. On driver cones, the resistive nature of material will dissipate the energy better if not concentrated and travel path is longer; additionally the pattern also makes a better match between the cone and the surround.