Contents

Expectations

The Soundgin is a new product offering from Savage Innovations.  This module is described as a wide range music, sound effect and speech synthesizer that can provide complete control over frequencies, waveform attributes and output dynamics.  This evaluation will outline the first impressions of using the Soundgin here at Acroname.  Having worked with a fair number of speech synthesizers, the notion of a sound generation module is not new.  What is new is the notion of mixing engines to combine and manipulate the characteristics of the desired waveform. 

We expected the Soundgin to exhibit the following characteristics:

• A tool to help learn and manipulate the Soundgin. 
• Built in samples and demo excerpts. 
• Flexible tools for waveform control. 
• Easy to interface with other controllers. 
• Thorough documentation about low level packet structure. 

Out of Box

Savage Innovations provided us with a Soundgin Evaluation Board with a socketed Soundgin module for assessment.  The evaluation board is divided into 5 different clearly labeled sections.  The sections include a RS232 serial interface, the Soundgin chip socket, a filter, an amplifier, and a power input.  Several test points are peppered throughout the board.  Most are labeled, but it would be an added convenience to have have the serial RX and TX test pad pins labeled.  We were provided with a 9V battery wiring harness with a polarized connector. 

As a getting starting footing, a PDF Datasheet holds a wealth of Soundgin information.  This resource discusses the Soundgin interface, functional block diagrams, operation, registers, serial commands, how to produce English speech, timing charts, example circuits and additional learning material. 

Savage Innovations has also created a software interface to help begin manipulating the Soundgin.  Software for can be downloaded from the Soundgin home page. 

Additionally, a User Forum has been established to help new users and the community share their experiences with the Soundgin. 

Test Rig

Interacting with the Soundgin necessitated a minimal bench set up.  Our test rig included a small 8-ohm, 0.5 Watt speaker, the evaluation board and a regulated power supply.  An extension wire was tacked onto the speaker and crimped with Molex pins to interface with the header socket on the evaluation board. 

Additionally, 4 wires were soldered onto the evaluation board to tie into the Soundgin UART lines.  The wiring harness is based on the serial interface standard which easily adapted to our interface connectors, therefore allowing a host computer to interface via a serial or USB port. 

The Soundgin Console software was downloaded and installed on computer running Windows XP.  It is not clear that Savage innovations will write a cross-platform application, but this would be appreciated by users of alternative operating systems (OS X, Linux, etc). 

Soundgin Console Application

The initial evaluation goals of using the software are to learn about the Soundgin capabilities, manipulate settings and discover how customizable the chip really is. 

Once the software was launched you are faced with a complex looking control panel.  At first use, it was unclear on how to get something to rumble from the evaluation board. 

Screenshot of the Soundgin Console application.

A quick menu survey uncovered an option to play "Carol of the Bells".  Once the song was triggered, an entertaining version came chiming from the speaker.  After the song finished, it was evident that the Soundgin is capable of producing some interesting sound effects. 

Attention was focused back on the control panel.  The datasheet describes the Soundgin as 6 mixing engines that can be combined or used independently to form rich audible output.  A closer look at the control panel, with this description in mind, quickly illustrates all the Soundgin's capabilities are laid out in a connected series of dials and buttons that conclude into a final output. 

A custom waveform in Mixer A, Oscillator 1 was created by adjusting the "Frequency" dial, clicking the desired "Waveform" type and setting the "Amplitude".  The "Master Output" level was adjusted to a level that could be heard from the test rig.  Additional wave engines were combined from Mixer B's different Oscillators and the result was fun to experiment with. 

Every user interface action is mapped to a defined set of serial commands.  The specific serial command for every setting (during a user interface action) is displayed in the upper window bar of the control panel.  This is of particular interest since later in the evaluation another system will send serial commands to the Soundgin.  It would be nice to see log output of every packets that get sent to the Soundgin from the GUI.  This would make writing the proper set-up commands easier when the time comes to interface the Soundgin with another system. 

Once the potential for creating custom waveforms was discovered, it was time to begin exploring the Soundgin's ability to generate English-like phrases.  The Soundgin does not have a built in vocabulary of words and phrases.  Instead, speech phrases are built upon the concept of using phonemes, which are the sounds we make when we speak.  The datasheet does a good job of discussing the subtleness of generating speech with phonemes. 

The lower corner of the control interface has some iconic symbols that open additional interface panes to manipulate the Soundgin.  A "Voice Properties" editor was opened by clicking on the head icon.  It seemed appropriate to try and produce the phrase "Acroname".  In the "Say Data" window, the following information was typed:

This text phrase produced a clear pronunciation of the phrase "Acroname". 

Serial Communication Using BrainStem Console Application

The BrainStem Console application was used to send structured serial packets to the Soundgin as an additional experiment.  The Console was used to provide quick insight on working with the Soundgin at a lower level than the User Interface software provided by Savage Innovations. 

A basic understanding of how the chip works opens the doors to rapidly manipulating the speaker output.  Soundgin allows every setting that can be manipulated through adjusting defined register values. 

The User Interface and the datasheet are two resources that help understand what information is necessary to write serial packets.  The datasheet provides a detailed section on serial communication and how to format appropriate packets.  The User Interface tool provided tips on what packets to send through the informational display in the window bar, as mentioned in the earlier in this review.  When combined, these two resources provide plenty of detail about what packets are necessary to get sound ringing from the Soundgin. 

As an example, a 600Hz sine wave at half the Soundgin volume was produced.  This required the following steps to properly set up the Soundgin:

• Set Master volume to 50%. 
• Set the Mixer A, OSC2 channel to 100% amplitude. 
• Store a value of 600 in the A2 Frequency Fine register. 
• Turn the Mixer A, OSC2 channel on. 

The following commands were issued from the BrainStem Console application:

To turn the Oscillator A2 off by removing it from the Mix, type the following in the BrainStem Console application:

All the system registers and settings can be changed through properly packeted serial commands as documented in the datasheet. 

Conclusion

The Soundgin module is a well thought out component for creating audible elements in a wide range of applications.  The tools and information developed by Savage Innovations provide a good starting point for experimenting with the Soundgin.  The User Interface application is a visually a bit overwhelming at first glance since it exposes all the functionality of the module.  This is quickly overcome after a few moments time of clicking and manipulating the dials within the control panel.  Once a fundamental understanding of the capabilites are gained, the control panel is a handy tool for rapid experimentation with a wide range of waveforms, sounds and phonemes.  After a brief use of the software, it meet the expectation of having a tool to help learn and manipulate the Soundgin.  As an added bonus, a built in demo of "Bells of Carol" provided the immediate feedback of the Soundgin proper set up.  The User Interface also helped illustrate the flexibility that one has over the waveform output and control.  It was very helpful having the packets get displayed in the upper window bar of the application. 

The Soundgin interface to other controllers is limited to a serial communication protocol.  Although this is fine for many systems, it could stand to benefit by incorporating a networking capability in a future version if possible.  The BrainStem Console helped demonstrate how the Soundgin reacts to packets that it receives across a serial line. 

The documentation on the Soundgin website, the datasheet and the user forums are a decent starting point for learning about interfacing to the Soundgin.  The available documentation will only improve over time with wider community usage. 

The Soundgin is packed with a number of features and is built on solid, fundamental groundwork for developing audible applications.  There is a lot of unexplored potential in the Soundgin module that is evaluation did not expose.  Hopefully, more users with help contribute their settings in some manner to help demonstrate Soundgin potential.  Acroname will be glad to add this product to our store as an additional tool for adding sound generation to future systems. 

Revision History:

• 2007-01-25: Page Created