Spectrum Lab Installation and Program Start

Contents

1. System Requirements
2. Installation and directory structure
3. Setting up the soundcard
4. Program start with command line arguments
5. Configuration data files
6. Running multiple instances of the program
7. Creating shortcuts for different configurations

Special topics:

1. How to avoid an unwanted audio bypass from the soundcard's input to output (Line-In to Line-Out)
2. How complicated this can be when using Creative Lab's Audigy 2 ;-)
3. How to install and run Spectrum Lab under Linux / Wine
4. How to use SL with software-defined radios like SDR-IQ or PERSEUS

See also: Spectrum Lab's main index

You will need the following to use "SpecLab":

- a PC with Win95, Win98, WinME, Win2k, WinXP, or Linux+Wine
- a soundcard with an audio input resolution of 16 bits
- a color graphics mode with at least 800*600 pixels with 256 colors
(a graphics mode with higher resolution and "true color" is preferred, and even required under WinXP)

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Installation and directory structure

To install the program on your PC, follow the instructions of the installation program. If the program requires special DLLs, they will be installed automatically. An uninstaller will be configured too, so you can remove this software easily if you don't need it any longer.

The default directory for the installation is C:\Spectrum . If not absolutely necessary, don't change this because some of the example settings contain absolute path names. Don't install the program in the crazy windoze 'Programs' directory. Some subdirectories will also be created:

\Data\

default directory for data files, like logged data files from long-term observations etc.

\Export\

contains some export file definitions and example user settings.

\Goodies\

contains additional information and special files. More info in a readme-file in the subdirectory.

\Html\

contains the online help system.

After successful installation, you may optimize some parameters for your requirements. You should (but you don't have to).....

• Adjust your soundcard settings for proper audio levels
• Check the level of the soundcard input with the input monitor
• Define the difference between UTC("GMT") and your local timezone
• Verify everything in the Configuration-Dialog
• Adjust the amount of memory used for buffering
• Test the digital filter on your PC
• Check if there is an unwanted audio bypass from the soundcard's input to its output, which spoils the soft-DSP
• If you intend to use Spectrum Lab with the SDR-IQ (by RFSPACE), read this document .

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Setting up the soundcard (or other input devices)

By default, Spectrum Lab uses the windows multimedia system for audio input and -output. Details on setting up the soundcard properly are here (in a separate file).

If your soundcard (or similar audio device) supports ASIO, look here because ASIO works better with some cards (especially at sampling rates above 48 kHz and resolutions above 16 bit).

To use SL with SDR-IQ or SDR-14 (by RFSPACE), install SpectraVue too. This will install the necessary USB drivers (by FTDI) which are not included in SL.

To process samples from your own A/D converter, consider using the file-based audio input, or send the audio stream towards SpecLab via UDP or TCP/IP (UDP is best suited for simple microcontrollers with Ethernet interface).

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How to check and avoid an unwanted bypass between the soundcard's Line-In and Line-Out

For real-time signal processing with SpecLab's internal DSP functions, an analog audio signal must get into the PC somehow, and to make to processed signal audible it must get out of the PC so we can listen to it with headphones or external speakers. This should be no big problem nowadays, because modern cards support "full duplex" operation, which means their analog-to-digital converter (ADC) and digital-to-analog converter (DAC) can run simultaneously. So we can use the DAC to produce test signals, and the ADC to analyze a different signal at the same time. Or we can use the ADC to digitize a signal, run it through some digital processing algorithm, and convert it back into an analog signal in real-time.

Sounds easy, because our brand-new soundcard has two audio jacks for this purpose, labelled "Line-In" and "Line-Out". So what's the point ?

Often things are not that easy. There are a lot of different signal paths inside a soundcard, different sources and destinations, and very different (and incompatible) ways to connect all these. The default settings of many cards are not suitable for us, because they feed the signal which enters the card through the "Line-In" port directly to the "Line-Out" port, for whatever reason. This is not very helpful here, because we only want the PROCESSED signal to appear at the "Line-Out" port. We also do not want the signal at "Line-Out" to be fed back into the analog-to-digital converter, because this may cause heavy feedback or heavy oscillation (making the stereo speakers jump through the living room !). Too bad ! Both situations must be avoided. In other words:

Be prepared to spend a few hours playing with your soundcard's own "volume control panel" (or whatever the manufacturer called it), until you managed that the audio input (from the "line-in" jack) only(!!) goes into the A/D converter, and the card's audio output (the "line-out" jack) is only fed from the D/A converter, without annoying bypass. The standard audio volume control program (SoundVol32.exe) is often all we have. If can be launched from SpecLab's  Options menu, to show the settings for "recording" (analog-to-digital conversion) and "replay" (digital-to-analog conversion). Just a few points to be aware of:

• On the "Recording Gain Control" screen ("Aufnahmesteuerung" in German) , only select the "Line-In" signal as recording source, or mute all other sources for recording. Unfortunately sometimes there is no "Line-In" as recording source, but an "Analog Mix" which makes it more complicated (as for the Audigy, see below).
• On the "Playback Volume Control" screen ("Wiedergabe", or "W-gabestrg." as CL likes to call it), only select "Wave" as playback source, or mute all the others. "Wave" often means the D/A converter.
• On some cards like the Audigy 2 (you have to enable "Line-In" also on the playback volume control screen, otherwise it won't record !!), the cure is not simple but possible then .. see below !
• Also enable the "Master Volume" on the playback panel, otherwise you won't hear anything from the speakers.
• Sometimes all these problems are gone if you use an ASIO driver instead of a standard multimedia audio device !

Some notes on Creative Lab's "Audidy 2" (tested with Audigy 2 ZS) and how to avoid Line-In -> Line-Out bypass ("feedthrough")

In May 2004 the author played with his new Soundblaster 2 ZS (by Creative Labs), because this card really supports analog sampling at 96 kHz (unlike some previous cards... but that's another story). Some first impressions...

• After installing the drivers by CL, the onboard audio device disappeared from the system control - most likely because there would have been an I/O address- and interrupt- conflict with the new card. Unfortunately this makes it impossible to use both cards simultaneously (which was planned to have ultimate separation between a "test signal" produced by one card, which should be fed to the input of the other card then). To get two cards working, one of the cards must be an USB card (like the Extigy, which does ***NOT*** support analog sampling at 96 kHz btw).
• Feeding a test tone from an external audio generator into the "Line-In" jack, running it through SL's software DSP chain, and sending the processed output to the soundcard's analog output ("Line-Out 1") showed the well-known feedthrough-problem, which means the audio from the Line-In port also went straight to the Line-Out port. More on this below...
• Simultaneous recording (A/D conversion) and playing (D/A conversion) at 96 kHz worked fine right from the start, without having to modify the soundcard interface code (I use standard multimedia subsystem calls to access the soundcard).

Unlike many other soundcards, there is no extra mute-control for the "Line-In" input for the speaker outputs (which they call "Quelle" in german). Even the good old SoundVol32.exe (part of windows) does NOT show a "Line-In" volume slider or select/mute control, but only an "Analog Mix" control. To make a long story shorter, I tried a lot with SoundVol32.exe and CL's "Surround Mixer" (SurMixer.exe) but always had this annoying bypass. Some web research revealed this solution, found in a newsgroup on the Creative Labs website when searching for "Audigy Line-In recording with Wave playback".

The question was:

> I have only Mic/Analog Mixer selector in Windows2000 record selector panel.
> Moreover, I can only record signal from LineIn only if I also select LineIn in Playback mixer.
> Does Audigy really has such kind of limitation?

An answer from "Sicabol":

> [...]
> You have to create a new EAX effect. Open the EAX Control Panel (in AudioHQ),
> click the Source tab. You will see a listbox with all the different sources which are playing now...
> Desactivate the sources you don't want to play by setting 0% to their original sound.
> I advise you to save your new setting.
> If you want to have the default settings back (after your recording),
> click "Reinitialisate the mixer" in the Creative taskbar.
> [...]

This answer was also very helpful for my application. But still, with the utilities from Creative it's complicated enough (I wonder if it's so unusual to let only the output from the D/A converter go to the output and nothing else ? .. anyway). You need the "EAX Console", which is only on the CDROM which comes with the Audigy (not just the drivers).  Here is the step-by-step procedure, which I used on a German PC:

• In the task bar: "Start"..."Programme"..."Creative"..."Soundblaster Audigy 2 ZS"..."Creative AudioHQ".
  A window opens, with an icon "EAX-Steuerung" (EAX Control). Double-click this icon.
• Select the "Master" tab in the EAX control panel / AudioHQ, where  you...
• set "Audio Effects" to "Benutzerdefiniert" (user defined), and type a name like "SpecLab" in the right field on the top, so you can export the settings you made as a file later,
• on the "Master" tab, move the gain sliders for "Orignalklang" to 100%, but "Nachhall" and "Chor" (chorus) to minimum (0 %).
• on the "Source" tab ("Quelle" in German), first select "Quelle=Wave", set the slider "Originalklang" to 100%, and all others ("Nachhall", "Chor") to 0%
• then, again on the "Source" tab (Quelle), select "Quelle=Analog Mix(Line/CD/Aux/TAD/PC" (instead of "Wave"), and pull all three sliders to zero ("Originalklang", "Nachhall", "Chor"). The names may be a bit cryptic, but at least this seemed to do the trick !
• Finally save the settings (click on the floppy icon, which should be enabled now), and/or export them as a file so you can easily switch back to them later. I saved the settings as "Audigy2_EAX_settings_for_SpecLab.AUP", to know what the file is for ;-)

Gone through all this ? Start SpecLab again, feed a signal into the Audigy's line-input. From SpecLab's main menu, select "Option"..."Volume control for RECORD". This opens the standard volume control program (which belongs to windows, not SpecLab, and not Creative Labs). Only the "Analog Mix" must be active as recording source. Because of the "EAX Effect" configured above, the "Analog Mix" is only the analog input (line-in) but no other fancy stuff. You should now see the spectrum of the input signal in the waterfall and/or spectrum graph, but not hear that signal (which you feed to the line-input) in the speakers. Next, connect the test signal generator to the output (in SL's "Components"-window), and turn the generator on to produce an audible sine wave. You should hear only the tone from the test signal generator in the speakers or headphones, but not see it in the spectrum display ! (otherwise, you still have that unwanted internal connection between A/D- and D/A-converter, which drove me nuts for several hours..). If you don't hear the test tone in the output, select "Options" in SL's main menu, and "Volume control for PLAY". Make sure the output to "Wave" is enabled (not muted), but that is usually the case by default.

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Some notes on various other soundcards

(just a loose compilation of feedback from other Spectrum Lab users)

• Audio 2 ZS and poor ASIO drivers
  Only runs at 48 kHz sampling rate; and -with a *different* ASIO driver- at 96 kHz. On my PC, 24-bit at 96 kHz sampling also worked well with the standard MME (multimedia) driver, while other users reported that they needed to switch to ASIO to get their cards running at 96 kHz . Strange, but no real surprise ;-)
• ESI Julia ("ESI Juli@")
  The Julia is a moderately priced card (about 140 Euros in early 2006), capable of stereo 24-bit sampling at 192 kHz sample rate. Successfully tested with Spectrum Lab since the integration of ASIO support. The Julia has a reasonably flat response to 90kHz and drops about 3dB by 96k.

For special purposes, you can pass a command line to the program when starting it. This is required only if you...

• want to have multiple instances of the program running at the same time, with each one using its own configuration file;
• want to have multiple instances of the program running at the same time, with one of them passing audio data (as master) to other instances (slaves).
• have a system with more than one soundcard, and you want to create desktop icons to start an instance of Spectrum Lab which uses a certain card (instead of the first detected audio device);
• want to help me debug the program, especially if the program crashes on your system ;-)

An overview of parameters which can be set through the command line is here.

If you only have a single soundcard on your system, or only need a single configuration, don't read any further on this page. It may be getting complicated.

The general syntax to start Spectrum Lab with command line arguments is like this:

SpecLab.exe <Machine-Config> <User-Config> [ <"Main Window Title"> ]

There are also some command line switches (options) which will be explained later.

Without using command line arguments, all parameters are saved in an old style INI-file named "SETTINGS.INI" in the current directory of the spectrum analyzer.

Usually, in this file both machine- and user-dependent data are saved.

If you want to have multiple instances of the program running at the time using different configurations, can tell the program which configuration file shall be used instead of the default "SETTINGS.INI". If you don't specify the name of the configuration file in the command line, the program uses "SETTINGS.INI" for the first running instance, "SETTING2.INI" for the second and "SETTING3.INI" for any further instance.

This can be achieved by passing one or more arguments to Spectrum Lab during program start. The first character in each argument must be a lower case letter defining the type of the argument, followed by a '='-character and the assigned value (e.g. a filename). Example:

SpecLab.exe m=Machine1.ini u=BandView.ini "t=Full Range Band View"

This will force Spectrum Lab to load the machine configuration data from "Machine1.ini" and the user configuration data from "BandView.ini". The main window will have the title "Full Range Band View".

A more-or-less complete overview of command line parameters is in the next chapter.
Command line parameters prefixed with a slash, which are not listed below, will be passed on to Spectrum Lab's internal command interpreter (see the "capture"-example below).

For special purposes, a few more command line options were implemented . There are:

• <filename.wav> Any string ending with the extension ".wav" is considered an audio file, which will be played (instead of processing the input from the soundcard, or whatever used as standard audio source).
• /si single-instance option. If the program is invoked with this switch, it will check if there is another instance already running. Instead of launching a new instance, the rest of the command line will then be sent automatically to the first (already running) instance, which will then evaluate it a few milliseconds later. See examples below.
• /q tells the program to quit automatically when "finished" with playing an audio file. If it does not play an audio file, it terminates itself immediately. Can be used together with the /si-option to fill Spectrum Lab's internal playlist !
• /debug runs the program in "debug" mode. This creates a logfile as explained in the troubleshooting guide.

Some special examples:

• SpecLab.exe C:\Spectrum\SpecLab.exe /si C:\Musik\Joe_Jackson\Classic_Collection\T03_Steppin_Out.wav /q
  plays a certain wave file from the harddisk, and terminates itself when finished.
• SpecLab.exe /si /q
  Checks if there is an instance of SL already running, terminates that first running instance (by sending the /q command = quit to the first instance), and finally terminates itself. Can be used in a batchfile to close down Spectrum Lab automatically.
• SpecLab.exe /si /capture
  Sends the command to produce a screen capture of the waterfall (etc) to the first instance of SpectrumLab. The same way, most interpreter commands can be invoked through the command line !
• SpecLab.exe /si "t=Oops, what happend to my title ?"
  Changes the window title of the first instance (which already ran before this command was executed).

See also: Communication with external programs,  Audio Clients and Servers , Using a system with more than one audio device ,   back to top

m= sets the name of the machine configuration file

u= sets the name of the user configuration file

t= sets a new title for the main windows

/si : option (switch) to send the rest of the command line to the first running instance. Explained here in detail.

/q : quit option. Instructs the program to terminate itself when "finished", usually with playing a wave file etc.

/nomenu : hides the main menu (and the window borders) after launching the program. To restore the main menu, press ESCAPE.

/debug :  For debugging purposes, specifiy the option /debug on the command line when launching Spectrum Lab. The program will write a file named "debug_run_log.txt" into the current directory, which may help me tracing bugs (answering questions like "how far did it get" - "where did it crash" - "why did it load so slow" - etc ).
This proved to be a very helpful debugging aid, when the program crashed on certain machines, using a certain windows version, a certain soundcard, etc. The contents of this debug log may look like this (just an example, when the program terminated "normally") :

21:22:27.5 checking instance...
21:22:27.5 init application...
21:22:27.5 creating main form...
21:22:27.5 Constructing main form
21:22:27.5 initialising ASIO wrapper
21:22:27.5 initialising SDR-14 / SDR-IQ control
21:22:27.5 creating CSound object
 (... a lot of messages removed here ...)
21:23:09.2 Closing I/O-port driver
21:23:09.2 Destroying COMM window
21:23:09.2 FormClose done     (this message indicates that the program closed "as it should")

If you find any messages like "Serious Bug", "Fatal Error", "Allocation Error", "Application Error" etc in that list, please let me know. Maybe I can fix it...

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Running multiple instances of the program

If is possible to have more than one instance of Spectrum Lab running at the same time on a single PC (if it's fast enough). Please don't try to let more than two instances run on one computer at the same time, unless you have a really powerful CPU (i never tried it on my 266MHz-P2). Because a single soundcard can only be opened by a single user, the second instance of Spectrum Lab will not be able to open the same audio device as the first. See "Using a system with more than one audio device" in the description of the configuration dialog.

If two instances of Spectrum Lab run side-by-side on the same PC, the program ensures that different configuration files are used as described above.(at least for the first and second started instance). This allows you to start two instances with the same shortcut icon on the desktop. Even different window positions and sizes are saved in the configuration files. During program start, Spectrum Lab checks if it "already runs" in another instance. If so, the title of the 2nd instance's main window will display something like this to avoid confusion:

The "[2]" in the window title also appears on some of the second instance's child windows.

Programmer's Information:

The detection of other instances uses mutexes. The first instance creates a mutex called "SpecLab1", the second a mutex "SpecLab2". This is also a  way to detect the presence of Spectrum Lab for other programs.

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You can create a shortcut ICON with command line arguments / parameters. Right-Click on an empty space of the desktop, then select "New..Shortcut (?? on a german PC: "Verknüpfung"), then find your way to the directory where SpecLab is installed, and append the command line parameters (using hyphens). The complete string should look like this (just an example, the path will be different on your machine !):

C:\Programs\SpecLab\SpecLab.exe "m=Machine1.ini" "u=BandView.ini" "t=My Title"

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Configuration data files

A lot(!) of configuration parameters are saved between to SpecLab sessions in old-fashioned INI files (not in the registry ! ). One contains only machine-specific data (and should not be copied from one PC to another), the other only stores application-specific data (and can safely be copied from one PC to another, to run the program with the same settings there).

 The machine configuration data contain:

• the information which audio device (soundcard etc) shall be used, and how it is accessed
• calibration tables for the audio device (true sample rates etc)
• interface setup to control a transceiver (COM-port, control lines etc)
• and possibly something more

The user configuration data contain:

• screen setup
• sample rate, frequency range, FFT resolution,
• amplitude range
• waterfall scroll rate, display colors, etc etc etc

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