The audio transducers - microphones and speakers are other essential elements of this installation. For this project, also in my usual artistic practice, I tend not to use high-end sophisticated equipments unless necessary. I don’t particularly like very clear and reality-resembling perceptual qualities of matters in a sense. The blurriness and indeterminacy of obsolete or less advanced technologies attract me better in media consumption and production. I also want to take this chance to appreciate their defects and experiment to see if I can explore any unconventional possibilities in them. For such reasons, I decided to buy second hand old microphones and make simple speakers with speaker cones and the easiest LM386 amplifier module.
For convenience in describing the work, I call the devices inside the acrylic box “interior” devices and those not “exterior”.
The latest decision on the work is that the signal to the original two speakers in the acrylic box will be mixed and output to a single speaker only. That means, inside the box, there are one interior speaker (cone) and one interior microphone, same as the exterior.
From eBay I’ve got two dynamic microphones (old but rather cool professional models in good conditions, both over 20 years old): RadioShack omnidirectional 33-1070D by Shure (black) & RadioShack unidirectional 33-3018 (grey).
The omnidirectional one is for the interior. I want it to pick up the room acoustics, not the sound from the speaker alone. That includes any reflections of sounds on the box’s inner walls.
The unidirectional one is for the exterior - the “earliest input” of the whole system of the installation. I regard this as something like the original speech of Alvin Lucier in “I Am Sitting In A Room”. Anyone can become the voice of any speech they want to deliver into the system and can experience how their sounds are manipulated by the system of temporal delay, room acoustics and audio technology. The distinction is that there will be infinite amount of varied “initial” input of sounds instead of one single vocalised prepared text like Lucier’s. Into the microphone you can sing, read, murmur, shout (not very recommended tho), introduce yourself… Anything will do.
For the speakers, at this stage I use LM386 to amplify the signals to low impedance speaker cones. I got a few already-assembled 200 gain modules. LM386 is quite limited in terms of amplification. For the external one I am still considering about using a ready-made loudspeaker instead, so that the audience can have a better audio experience of the ambience inside the acrylic box (which signifies a “parallel universe” in the concept of the work).
The speaker cones are placed inside these small and thin acrylic cubic boxes just to test how much sound the acrylic can block. I also hang the speaker cones suspended. Simply put, sound is vibration. If the speaker cone stands on one inner surface of the box, vibration, when it makes the cone hit the box, will further cause sounds that are not from the signal itself - not desired for this particular project. Therefore, the inner speaker will be hung suspended with fishing string, so it’s not in direct contact to any plane of the box. The walls are very thin, yet the difference between the loudness is already very obvious. I will use thicker acrylic to build the “parallel universe”, so I expect that the soundproof quality will be quite good.
The system of audio devices illustrated:
The signal from the exterior microphone (33-3018, unidirectional) and “monitor” (output) from the playback cassette dictaphone are mixed by Behringer Xenyx 802 analog mixer, then output to the interior speaker (amplified via LM386 (int.)). The interior mic (33-1070D, omnidirectional) picks up sound inside the acrylic box and it’s connected to input of Behringer HA400 4-channel amplifier. Output 1 of the amp is sent to “mic” (input) of the recording cassette dictaphone; output 2 is to the exterior speaker (amplified via LM386 (ext.)).
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