Rerurn to Romy the Cat's Site


In the Forum: Audio Discussions
In the Thread: Sounds of Science
Post Subject: Eductor hornPosted by Gargoyle on: 8/25/2024


I have been considering ventilation of the horn surface, as counter-intuitive as that is. If you have ever seen an "eductor" nozzle in a fish tank you will know what I mean.

Consulting GPT and pushing past the pedestrian answers and cautions to obvious problems of ventilating a horn, it seems to agree that conceptually at least, there could be some benefit to the lower frequencies in particular.

In my mind I pictured a bunch of circular vents that were "light tight" to have a constant hard surface to propagate sound off, but does not have the suction of a solid surface.
ChatGPT suggested venting the connection where the driver meets the horn. That's clever, it avoids some issues it was concerned with originally.
I added my depiction of circular vents farther down the horn, it identified some benefits of that, being more gentle and phase friendly maintaining good impedance matching.

There is no free lunch, necessarily, however I don't see why the output "has" yo go down, it could increase. I would be fine with a decrease if there was a benefit to lower frequencies. (Quality)

Venting is likely to benefit below 1kHz.
Mid range would have a neutral impact 1kHz - 5 kHz.

High frequencies would be negatively impacted 5kHz and above.

The thought of using a reed valve to reduce back pressure occurred to me but I don't think it's worth something potentially as difficult as that yet. On a big bass horn that might be the ticket.

Rerurn to Romy the Cat's Site