Rational Acoustics Smaart I-O User manual
User’s Manual
Copyright 2011 Rational Acoustics, LLC.
All rights reserved.
Overview
The Smaart I-O is a 2-in, 2-out, mic preamp and USB audio interface
device designed specically for professional audio measurement
applications. It is designed to accommodate signal levels common in
professional audio systems, to integrate seamlessly with Smaart
acoustic measurement and analysis software and to be solid, simple
and easy to use. The Smaart I-O features balanced dierential inputs
and outputs, low-noise programmable gain microphone preamps with
50 dB of gain in 1 dB steps, an extremely stable and robust 48V phan-
tom power supply and precision referenced ADAC to ensure consistent
electrical sensitivity, linkable sample clock and external powering
options, all packed into a compact package with no external controls.
A simple control program (included on the supplied CD ROM) sets
preamp gains and phantom power selection, and automatically
integrates with Smaart measurement and analysis software. The
control program also provides rmware update capability and can
rename the Smaart I-O at the hardware level – an important feature
when using multiple devices with Smaart.
The Smaart I-O by Numbers
Front Panel
USB
Ch.1 Ch.2
ClipClip
SignalSignal
PhantomPhantom
2x 2 USB Audio Interface
1. Signal presence indicators illuminate when the input signal level
exceeds about -27 dB FS.
2. Clip indicators light up when input signal levels exceed -6 dB FS.
3. USB indicator glows blue when connected to your computer, purple
to indicate external clocking, or ashes red if unable to connect.
4. Phantom power LEDs light when 48 V phantom power is turned on.
Back Panel
1 2
31 2
312
3
12
3
5. Balanced line level outputs.
6. Balanced Mic. Line inputs. Jack accepts XLR or 1/4” balanced or
unbalanced TRS or TS connector. 1/4” input has a ~20 dB pad inline and
is not connected to the phantom power supply.
7. Sync ports for synchronizing the sample clocks between multiple
Smaart I-Os. Accepts standard RJ-45 Ethernet patch cables.
8. USB connector.
9. Optional external power connector. Normally the Smaart I-O is
powered by the USB port on your computer and requires no external
power. However you can also connect a 5 Volt DC power supply to this
jack if you do not wish to port power the Smaart I-O for some reason,
for example if your computer is unable to supply sucient power for
stable operation.
Hardware Installation
Physical installation of the Smaart I-O is just matter of connecting it to
one of the USB ports on your computer using a standard USB periph-
eral cable (supplied). The Smaart I-O is a USB Audio Class device,
meaning the drivers for it are built into the MacOS and Windows
operating systems and should be loaded automatically when the
device is detected.
Software Installation
Windows users: Run setup.exe from the CD included in your package
(or better yet, download the latest version from the Rational Acoustics
web site) and follow the prompts in the installation wizard.
Mac users: Drag the Application bundle from the enclosed CD (or
better still, from the disk image le containing the latest version,
downloaded from our web site) to the Applications folder on your hard
drive. You can then drag the icon from your Applications folder to your
dock bar to create a shortcut if you wish.
The latest version of the Smaart I-O control applet can be found at:
http://www.rationalacoustics.com/smaart-i-o
If one or more Smaart I-O's is connected to your computer when you
run the control program it should automatically detect and connect to
all the units it nds. In the case of multiple units, additional control
strips are appended to the control applet for each unit found.
It is important to keep the control applet running when using the
device with Smaart. Smaart does not communicate directly with the
Smaart I-O but when the control program is running, it reports input
gain settings for all connected units to Smaart (version 7.3.2 or higher).
This information is used to ensure that calibrated SPL and spectrum
measurements remain calibrated when you adjust the input levels.
When using the Smaart I-O with Smaart you will see some options
become enabled in Smaart’s Audio Device Options dialog tab and also
in the sound level calibration window, that are only available when
using an input device whose electrical sensitivity is known to Smaart.
Please refer to the Smaart help le for details.
Linking Multiple Devices
The Smaart I-O includes a proprietary scheme for linking the sample
clocks between multiple units to ensure that they run at the same rate.
This opens up the possibility of making dual-channel transfer function
Single Device View Multi-Device View
an impulse response measurements using a reference signal from one
Smaart I-O and a measurement signal from another. It may not be
necessary in all cases to actually use this feature, as the Smaart I-O can
also use time cues from the computer’s USB controller to keep its clock
running at a highly consistent rate, but physically linking Smaart I-Os
to run under a master clock signal provided by a signal designated
device still provides an extra measure of consistency.
To synchronize the sample clocks between multiple I-Os, rst make
sure all units to be linked are disconnected from the computer. Then
designate one unit as the clock master and connect an RJ-45 patch
cable to its Sync Out port (the bottom RJ-45 jack). Connect the other
end of the cable to the Sync In port of a second unit. To add additional
Smaart I-Os to the chain, connect the Sync out on the second unit to
the Sync In on the third and so on.
When all the link cables are installed, connect a USB cable from your
computer to the rst unit in the chain (the designated clock master),
then the second and so on -- if additional units are to be linked, keep
working your way down the chain until all units are connected to the
computer. The Smaart I-O automatically detects the cable connections
on power-up and congures itself appropriately as the clock master or
a downstream client, depending on which jacks are populated. The
USB LED on the front panel of slaved units changes from blue to purple
on power-up to indicate that they are being externally clocked.
Please note that you may still see some variance in delay times from
one measurement to the next in dual-channel measurements made
using signals from two dierent devices. This can happen even when
the sample clocks are synched between devices, due to ambiguities
in the timing of multimedia events by the operating system. What
clock linking ensures is that once a measurement is underway, the
delay between signals should remain constant for the duration of the
measurement. You may therefore wish to designate one microphone
as your reference for measuring delays in the system under test and
connect that microphone to the same device being used to capture
the reference signal.
Warranty & Service
Rational Acoustics LLC warrants the Smaart I-O against defects in materials
and workmanship for a period of ONE (1) year from date of original retail
purchase. This is a non-transferable warranty that extends only to the original
purchaser. Rational Acoustics will repair or replace the product at its discretion
at no charge if the product proves to be defective when returned to us, freight
charges prepaid. Warranty does not cover or apply to (a) misuse, mishandling,
and abuse, (b) products that have been altered (c) products not used in
accordance with manufacturer’s instructions or recommendations, (d) normal
wear and tear, (e) damage that has occurred during shipping, (f) acts of God.
THE WARRANTY AND REMEDIES SET FORTH ABOVE ARE EXCLUSIVE. RATIONAL
ACOUSTICS LLC DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE. RATIONAL ACOUSTICS LLC IS NOT RESPONSIBLE FOR
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING FROM ANY
BREACH OF WARRANTY OR UNDER ANY OTHER LEGAL THEORY.
For warranty repair, please contact Rational Acoustics for an RA (return
authorization) Number before sending your unit in for evaluation. Product
returned without an RA Number may experience delays in evaluation, repair
and/or replacement. When sending a unit for repair, please do not include
accessories, including carry cases, cables, or adapters. You MUST include
proof of purchase with your unit when returning it to Rational Acoustics for
warranty repair.
Rational Acoustics LLC
Service Evaluation RA #XXXXX
241 H Church Street
Putnam, CT 06260 USA
Telephone: +1 (860) 928-7828
Technical Support / Bug Reports
For technical support and bug reporting on the Smaart I-O please contact:
Rational Acoustics LLC
E-mail: [email protected]
Telephone: +1 (860) 928-7828
www.rationalacoustics.com
Printed in USA
Table of contents
