Rare Waves Lite2Sound QB User manual

Lite2Sound QB is a portable audio device for receiving modulated light. It is made
specially for creative audio enthusiasts, sound designers, music producers, and
performing artists. Imagine accessing ambient music that is previously unheard,
yet full of accidental beauty and strange textures.
With Lite2Sound you’ll uncover hidden sources of audio frequencies that are all
around us waiting to be discovered. That's because the technology behind modern
high-tech light sources is often ickering at frequencies too fast for our eyes to see,
yet within our hearing range - if we only had a way to listen. That's what Lite2Sound
does. It reveals these invisible tones to your ears and lets you blend the frequencies
into chords as you move it through space and aim it like a camera.
The wooden case design is inspired by vintage radio receiver sets. It offers a classic
yet low-key appearance that won’t arouse distracting attention when used for field
recordings. Its built-in speaker and battery means no hassles from plugs and
cables.
What is Lite2Sound QB?
Audio connections
The 3.5mm jack is a mic-level audio output that can be connected to the stereo mic
input of a camcorder or portable audio recorder. This is a direct output (pre-
limiter). Use a shielded audio cable for best sound quality.
The 1/4” jack is a line level output, and is post-limiter. Plugging into this jack will
mute the internal speaker. Connect it to any audio device with a 1/4” line input.
You can also plug in headphones, but note that audio will only be heard on one
side of the headphones.
A standard camera tripod mount is built in to the base. Mounting it on a tripod
makes it easy to position and focus on interesting sources.
Tripod mount
Suggested listening
Begin by exploring around the home. Try video screens, displays, digital toys, etc.
Public spaces that are saturated with technology provide many interesting
sounds: arcades, midways, toy stores, video showrooms, casinos, LED light art
installations, etc.
Night time driving in the city gives an ever changing soundscape with surprises.
For best sound quality, use it at night and aim it away from background lighting.
Sunlight increases the noise oor. AC grid-powered light bulbs add mains hum
harmonics.
Lite2Sound QB contains several refinements that distinguish it from the previous
versions we have offered. Like the PX model, QB has automatic exposure control
so it can work well in either bright or dim light conditions, without changing any
settings. The QB also includes an audio limiter for smoother sound quality and
low distortion.
The QB has a built in copper foil shield to prevent electromagnetic interference
from contaminating the audio.
Additionally, the QB has a direct audio output for connecting to the mic input jack
of video recorders. This output bypasses the power amplifier and AGC limiter
circuitry, allowing the best dynamic range and lowest noise oor.
What’s new in this version?
Use the internal 9V battery, or connect an AC adapter to the power input jack. This
unit requires a 9 VDC regulated power source with tip positive polarity. It is
protected against reverse polarity and over-voltage.
Power supply
Lite2Sound QB Photodiode Ampilfier | User Guide 1.0 Rare Waves LLC USA rarewaves.net
A u t o G a i n P h o t o d i o d e A m p l i f i e r

Lite2Sound QB Photodiode Ampilfier | User Guide 1.0 Rare Waves LLC USA rarewaves.net
AC Adapter
9 VDC
Direct Output
3.5mm dual mono
Mic level
(pre-limiter)
Power LED
Volume limiter control
and ON/OFF switch
Line Output
1/4” mono
-10dBu
(post-limiter)
Sensor window
Tripod mount
1/4-20 thread

Q&A
Q. Can I use it with a laser pointer to hear vinyl records?
A. Yes, but only in low quality. It helps to focus the laser to a pinpoint with a small
convex lens (not included). Spin the vinyl on a turntable and reect the laser spot
off of it. Monitor the reected ickering laser light with Lite2Sound. Additionally,
many textured surfaces can make audio if they are in motion while the laser is
reected off of it.
Q. Can I hear sounds from nature with Lite2Sound?
A. Yes, sometimes. On a clear day, you can hear air moving in the atmosphere if you
aim Lite2Sound in the direction of the sun. Humming of insect wings can be heard
if light is striking them. It works best if you don't point Lite2Sound directly at the
sun, just tilt it off-axis slightly. Any shiny vibrating object which reects the sun on
a clear day is a potential source of audio.
Q. Can I hold it up to a telescope and hear sounds from outer space?
A. No. That requires extreme sensitivity which it is not designed for.
Q. Can I locate infrared motion detectors and other IR sources with it?
A. Yes, sometimes. It will not react to passive infrared sensors, but active infrared
motion detectors such as found in home thermostats are easy to locate because
they emit bright pulses of infrared, making a distinct clicking sound. Since
Lite2Sound receives near-infrared as well as visible light, it will respond to many
infrared remote controls and modulated IR communication signals.
Q. Can I use it as an optical pickup for stringed instruments?
A. Yes, but only for low fidelity experimental purposes because you'll need 3 or 4
hands. Focus a bright LED ashlight on the strings, and point Lite2Sound at it.
Works best with a black guitar, or place a square of black paper behind the strings.
Q. What does pure unmodulated light sound like?
A. Light that is not ickering at all, such a ashlight running on batteries, is heard
as pink noise or static.
Q. Can I hear colors with it?
A. No. It responds to variations in brightness of light, but does not distinguish
between colors.
Q. Could it work as a free space optical communication receiver or photophone?
A. Yes, it could work as a photophone receiver, if you carefully add a focusing lens
or optics to make it more directional. Note that Lite2Sound QB only receives, it does
not transmit.
Q. Can I make a laser microphone with it for eavesdropping on conversations?
A. This device is not intended for surveillance. We have not tested this application.
Automatic gain (x2)
Lite2Sound QB has two automatic gain control circuits. They work together to
provide the fullest signal level without distortion.
The first AGC layer adjusts for variations in brightness. Think of it like automatic
exposure control in a camera.
The second layer of AGC adjusts for variations in modulation intensity of the source
you are monitoring. It works like an audio limiter or compressor, preventing the
output form distorting even if there are large changes in the input signal level.
Recording tips
For best recording quality, use the 3.5mm direct out jack. This provides the lowest
noise oor and best dynamic range. The signal is low level and requires a
microphone preamplifier. This output is not affected by the volume limiter.
The 3.5mm jack will deliver a dual mono signal to the stereo mic input of your
camcorder or other recording device. It is an unbalanced output. Use either a
mono (TS) or stereo (TRS) type cable. Shielded cable is required.
If connecting to pro audio equipment, you can use a DI box, ¼” Hi-Z instrument
input, or an adapter cable with XLR male output, as required to match your mic
preamp's input connector.
The audio signal from the ¼” output jack is post-limiter and can be connected to
headphones for monitoring.
For best recording, mute the internal speaker by patching something to the ¼” jack.
Either connect headphones, or “dead-patch” it with a headphone adapter plug.
For best results when using the 1/4” line output for recording or audio processing,
set the volume limiter control to maximum. This gives the most dynamic range.
The control knob sets a limit for the maximum loudness of the speaker.
Under some conditions, turning the knob won’t affect the speaker loudness (don't
assume the unit is broken). If the unit is not receiving strongly modulated light,
such as in darkness, then the knob will have little or no effect on volume.
The knob affects the audio level of the 1/4” output. It does not affect the signal from
the 3.5mm direct output jack.
To minimize the AGC effect, turn the knob up to its maximum setting.
Just one knob
Lite2Sound QB Photodiode Ampilfier | User Guide 1.0 Rare Waves LLC USA rarewaves.net

Changing the battery
Specifications
The unit is powered by a standard 9V alkaline battery. Before you begin, move to an
uncluttered table top with good lighting.
Turn the unit upside down and remove the four screws at the corners with a Philips
screw driver. Gently slide the top half of the case off of the base. The illustration on
this page shows how the lid separates from the base.
The lid is tethered to the base by a ground wire. Don't pull on the ground wire, or the
copper shielding may tear off.
The groove that the control panel slides in is fragile. Be careful not to break the thin
edge of wood around the groove.
Slip the old battery out of the battery clip, then install a fresh battery. Slide the two
halves of the case back together, and replace the four screws. Don’t over-tighten.
Dimensions...................... 3.5” (89 mm) cube
Weight...............................14 oz (400g)
Sensor type...................... .PIN photodiode
Sensor reception angle.....8 degrees
Wavelength sensitvity......450 - 1100nm (blue to near-IR)
Audio outputs...................3.5mm dual mono (mic level), 1/4” mono (-10 dBu)
Power source.................... 9 V battery or AC Adapter
AC adapter........................ 9 VDC output, regulated, tip positive, 2.1mm plug
AC adapter
The unit can be powered with a 9 volt DC adapter. The polarity of the plug is tip
positive. A regulated type adapter is recommended. (For best sound quality use
battery power)
Lite2Sound QB will not work with tip-negative AC adapters for FX pedals.
This unit is protected against reverse polarity and over-voltage. If you connect an
unregulated type AC adapter, or one that delivers more than 10 volts, an internal
fuse will activate. The fuse disconnects the power supply to prevent damage. If
this happens, wait a few minutes for the fuse to reset itself, then try a different
adapter or battery.
Ground Wire
( FRAGILE )
General care
The case of Lite2Sound QB is made of eucalyptus wood fiberboard, and is not
meant to be moisture resistant. Avoid condensing humidity and damp conditions.
Lite2Sound QB Photodiode Ampilfier | User Guide 1.0 Rare Waves LLC USA rarewaves.net