6 Channel Hemisphere Update

  • The purpose

Since many laptop orchestras or laptop ensembles exist these days, I might not need to introduce the purpose of the hemisphere speakers.  Instead I would like to present the use of 6ch-hemisphere speakers. What we have done during the summer of 2012 is to expand the number channels of our speaker’s function. Now, it is not only for laptop ensemble purpose but also for an acousmatic music, a spatialized music, or other experimental music purposes.

Usually Hemi-speakers are made with four to six speakers in a Hemi-speaker, and the speakers are connected to one or two inputs sound source, which means six speakers within the Hemi-speaker make same sound to all direction. This is an undoubtedly useful device for on-stage performance. However, as you can assume from the title of this page, we extended the stereo or mono hemi-speaker to 6channel Hemi-speaker using specialized amplifiers purchased from Isobel Audio. The main purpose of this re-design is to make a hemi-speaker that can diffuse or control each speaker individually, or that can resonate six diversified sounds on each speakers differently. As a result, the speaker might have extensive potential to do the other experimental music.

  • Preparation

We had three parts to be assembled. The body of the hemisphere speaker which has six speakers, the customized front control panel, and 6ch-amplifier circuit.

Picture of the Hemispeaker Case

Since we used the hemi-speaker we already had made, I will skip the preparation of the body parts(Case and speakers). If you need information of the speaker component, click here.

– Parts for the front panel

We customized the front panel which has volume controls, on/off switch and plug-ins. Material of the panel is acrylic. It was designed by Nick Hwang(EM/DM, composition Ph.D candidate) using the Laser cutter at School of Art in LSU.

The front panel has five parts.

  • LED light
  • DC plug-in
  • Switch (KCD1-105)
  • 6ch-XLR chassis (Neutrik NC6FP-1)
  • Volume Knob

(Click the picture to see the larger data sheets)

Switch (Rocker KCD1-105)
6ch-XLR Chassis (Neutrik NC6FP-1)
Picture 1(Parts)

In the picture above, lay out an acryl panel, LED, DC plug, Switch, 6ch-XLR, volume knob.

Picture 2 (wires of the amplifier)

In the picture 2, the amplifier has six pair of wires for six speakers(LEFT wires), one pair of DC power(TOP wire), one ribbon wire which connected to 6ch potentiometer(BOTTOM) , and one LED light for audio indicator(RIGHT).

Picture 3 (the Amplifier)

Picture 3 is close look of the amplifier.

 
  • Building

    Here is the diagram for assembling.

Diagram 1 (6ch-hemispeaker)

Mainly, there are three parts we assembled.

  1. The front panel to the amplifier
  2. The amplifier to the speakers
  3. The hemisphere case
  • The front panel to the amplifier

First of all, we designed the front panel with acryl plate, which is leftover stuff from previous project, and cut with the laser cutter in School of art. After the laser cutter, we need to bend the panel, since the surface of the case is round-shape. So, we used a bake-oven to hit-up the material(475F., 1:30min), and bended it.

After the bending the panel, connected the three wires of the amplifier to the front parts and one LED light. (1)D.C socket to the switch, (2)LED light wire, (3)D.C power to the socket and the switch, (4)Potentiometer to 6ch-XLR.

In the picture below, left and right are swapped.

Diagram 2 (the Wiring of the front panel)
Picture 4  (Back of the front panel)

 

  • Amplifier to speakers
Diagram 3 (Order of six channels)

Before we connected the wires, we already had attached the wire connectors at the end of wire with a clamper. And then we connected the six outputs-wires from the amplifier to the each speakers; Red wire to positive, black wire to negative. In the picture on the right, we can see the order of the channels.

  • Case assembling

There are three steps we did for the case assembling. (1)Glued the wooden base for the amplifier, (2)Skewed the front panel, and (3)Skewed the hemisphere case.

Picture for the skewed panel

  • Parts besides the hemi-speaker

Since the 6ch-XLR is not general in audio-equipment market, we should make our own cables for use. We made six cables that have one 6ch-XLR male in one side and in the other side six RCA male connectors, and also made a mono channel from TRS female to 6ch-XLR male cable for general purpose.

Cable for 6ch XLR to 6 RCA
Cable for XLR to mono TRS
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