Detailed information on Helix-AG180Z

The 3D-Spiral Horn Speaker Building

Added on 7 Aug. 2007
Updated on 1 Sep. 2007

This AG180Z is the second of "Z" series following AG220A. "Z" was named after the upper configuration of fins.
AG180Z was built using 18 mm MDF, and mounted with 12 cm (4.5 inches) full range, Fostex FE126E.
A small amount of damping material was used.

Thickness of the plank is 18 mm for cabinets and fins.
Edges of the fins are rounded for a smooth sound passage.

	The edges of the fins were rounded for a smooth sound passage.
	Trial assembly 1.
	Trial assembly 2.
	Trial assembly 3.
	Trial assembly 4.
	The finished assembly.

Measurements of Helix-AG180Z

Added on 7 Aug. 2007

Because of malfunction of the microphone (Primo EMU-4535-2), the new one (Microphone Madness MM-TMM-1) was used.
Therefore, a direct comparison with old data is not appropriate.

Resolution 21.53Hz ; Span 22050Hz
Magnitude -140 to 0 dBFS (FS : full scale)

listening position

stereo,2m,center

mouth output

mono
center
(border of the mouth)

High resolution measurements

Resolution 5.383Hz ; Span 5512Hz
Magnitude -140.0 to 0.0 dBFS

	listening position stereo,2m,center
	mouth output mono center (border of the mouth)

Impedance measurements

Vertical axis has an arbitrary linear scale and is proportional to the impedance of the driver.
Resolution 5.383Hz

Modification of Helix-AG180Z

Added on 1 Sep. 2007

For improvement of bass output, the front opening was enlarged to 12.6 cm² from 7.6 cm².
The distance between centers of two 22mm holes was 40 mm.

The following comparisons of the frequency and impedance responses between before and after enlargement indicate that there is no significant change of the sound quality with the opening area.

Resolution 21.53Hz ; Span 22050Hz
Magnitude -140 to 0 dBFS (FS : full scale)

listening position

stereo,2m,center

mouth output

mono
center
(border of the mouth)

Resolution 5.383Hz ; Span 5512Hz
Magnitude -140.0 to 0.0 dBFS

	listening position stereo,2m,center
	mouth output mono center (border of the mouth)
	Impedance