DANLEY · DIGITAL HORN Diaries
Chapter 02 — A letter

For Tom. Beam steering, phased arrays, Huygens' principle & lobes.

A nice endeavour is coming. I remember the first days of the SBH series, and I always wondered why only the SBH10 and 20 were developed — and no further.

Sebastián Rivas Temuco · southern Chile Addressed to
TOM DANLEY
CorrespondenceJul 30, 2025
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02Chapter

A nice endeavour is coming.

On the new summator, the paraline principle, the SH25 polar pattern as a seed for a grid of little speakers, and a secret tool inside Direct for the end-fired research.

Opening sketch
Fig. 01

The opening sketch — phased arrays, antennas, and lobes as one family of ideas.

Hi Tom. Yeah, I understand what you are talking about. Now I am super interested on the new summator. Can you send some SketchUp drawing or anything to let me understand better what we are talking about.

I barely remember the principle behind the paraline. I remember something like —

Paraline principle
Fig. 02

The paraline principle, as I remember it.

And this was already very incredible. I remember the very first days of the SBH series. I always wondered, though, why only the SBH10 and SBH20 were developed and no further. Now if you found a better approach — even better, that would be great.

About the need for a simulation using the SH25 as the starting point, I am all yours. I’ll prepare this as a secret tool inside Direct, like the ones I gave you for investigating the end-fired approaches. About that — what happened with that line of research? Did Mike grasp the concept fully?

End-fired cannon sketch
Fig. 03

End-fired cannon — missing information. A thread to pull on.

SH25 polar pattern, as a grid.

So, with the SH25 polar pattern, a grid of little speakers would behave something like this — from 500 Hz to 5 kHz, frequency by frequency.

SH25 grid polar 1
Fig. 04

SH25-based grid — pattern at a first frequency step.

SH25 grid polar 2
Fig. 05

Next frequency step.

SH25 grid polar 3
Fig. 06

Next frequency step.

SH25 grid polar 4
Fig. 07

Next frequency step.

SH25 grid polar 5
Fig. 08

Next frequency step.

SH25 grid polar 6
Fig. 09

Next frequency step.

SH25 grid polar 7
Fig. 10

Next frequency step.

SH25 grid polar 8
Fig. 11

Next frequency step.

SH25 grid polar 9
Fig. 12

Next frequency step.

SH25 grid polar 10
Fig. 13

Next frequency step.

SH25 grid polar 11
Fig. 14

Next frequency step.

SH25 grid polar final
Fig. 15

Last frequency step of the sweep — the family of polar responses seen as one picture.

You can put sound only where the individual transducers also put sound.
— the constraint we work under

So we need to do this kind of research over different models. I am going to put together a tool to do this easily and see results. Also I think any coverage would be helpful for the Digital Horn, although for very pronounced or asymmetrical coverages I have seen something like these words — "you can put sound only where the individual transducers also put sound". So this array with SH25s would be a high-Q cluster with not-so-pronounced coverage lobes, but very good for soft aiming with precision.

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