Audiotec Fischer MTK 1 Einmesssystem Measurement Toolkit

Hardware Preparation

Before performing the first measurement, connect the measuring microphone to its preamplifier and your computer. Follow these steps:

• Connect the XLR plug to the measuring microphone.
• Connect the XLR jack to the microphone preamplifier.
• Connect the miniUSB plug of the included cable to the microphone preamplifier.
• Connect the USB plug to a free USB port on your computer.
• Set the gain control on the microphone preamplifier to the center position.

After connecting the microphone preamplifier to your computer, the transparent ring should light up blue. Activate the phantom power on the microphone amplifier by pressing the tiny push button marked "48V". The transparent ring should then change its color from blue to red.

Important Notes:

• It is strongly recommended not to directly hook up the microphone preamplifier to the microphone.
• The measuring microphone must be fully connected to your computer before starting the Audio Analyzer in the DSP PC Tool. If you connect the microphone after starting the software, it will not be detected.
• Check your computer's audio settings in the control panel to ensure the microphone is detected.
• Ensure the automatic gain control (AGC) is deactivated.
• Set the microphone volume to 100%.

Test Signal and Analyzer Launch

The measurement of frequency response curves requires a test signal, typically "pink noise". The included USB memory stick contains this test signal as an uncompressed WAV file (preferred) or an MP3 file. You can connect the USB stick directly to your car audio system if it has a USB connector. If not, burn the WAV file to an audio CD.

Launching the ATF Real-Time Analyzer:

Using the Audiotec Fischer DSP PC-Tool in demo mode without a connected DSP device will result in limited functionality. In this mode, the measurement duration is limited to 1 second, preventing a reasonable frequency response measurement. Full functionality is available when a DSP device is properly connected.

Visual Description: A screenshot of the ATF Real-Time Analyzer software is displayed, showing frequency response bars. In demo mode, a message "DEMO" is prominent, and a dialog box "AudioAnalyzer Demo Mode please connect an ATF Device! OK" is shown.

Configuring the Audio Analyzer

To configure the audio analyzer for measurement, click the green marked "SETTINGS" button or press 'c' on your keyboard. This will display the main analyzer interface.

Visual Description: The ATF Real-Time Analyzer interface displays frequency response bars. Key controls are labeled START [S], TIME: 20, ALWAYS ON TOP OFF [t], SAVE RESULT [r], SETTINGS [c]. The frequency axis ranges from 25 Hz to 20 kHz, with amplitude levels indicated on the right.

After clicking "SETTINGS", a new menu appears. Ensure your connected microphone is selected as the audio device. It's possible for the computer's internal microphone to be selected by mistake, leading to incorrect results.

Visual Description: A screenshot shows the analyzer interface with an audio device selection menu. The selected device is labeled "Audio device: Microphone (USB Audiogera)". Options like "Load ATF Reference", "Load Flat", "Load File", and "Save File" are visible.

Configuring the Reference Curve

Select your desired reference curve. The "ATF Reference" is the default, matching industry standards. A linear (flat) reference curve is available for home applications but is not recommended for car audio measurements as it yields unsatisfactory results.

You can also define a custom reference curve. Each frequency band can be adjusted individually. For example, the high-frequency roll-off of the "ATF Reference" can be equalized.

Visual Description: Two screenshots show the reference curve configuration. The first shows the default "ATF Reference" curve. The second shows a modified curve where the high-frequency roll-off has been eliminated.

Save your custom reference curve using "Save File" for later recall via "Load File". Return to the analyzer display by clicking "BACK" or pressing 'b' on your keyboard.

Analyzer Functions Explained

The ATF Real-Time Analyzer interface includes several key components:

1. Colored Bar (Top): Indicates sound level sufficiency.
   
   • Yellow: Sound level too low. Increase car radio volume or check microphone sensitivity.
   • Green: Sound level is correct.
   • Red: Sound level too high. Reduce volume or check microphone sensitivity.
2. Values Below Bar: Measured sound pressure level per frequency band in [dB] (relative values).
3. Orange Bars: Measured frequency response in 1/3rd octave steps.
4. Grey Bars: Chosen reference curve in 1/3rd octave steps.
5. Slider 1: Shifts reference curve bars vertically.
6. Slider 2: Shifts measured frequency response bars vertically.
7. Center Frequencies: Displays center frequencies of frequency bands in [Hz].
8. Deviation Line: Shows deviation of each measured frequency band from the reference curve in [dB]. These values can be used to adjust the 1/3rd octave equalizer in the DSP PC-Tool. Positive values indicate boosts, negative values indicate cuts. Be cautious with strong boosts (> 4dB) to avoid distortion. Deep cuts (-10 dB or more) are generally unproblematic.

Measurement Controls:

• START [S] (Yellow): Click to begin measurement or press 's' on the keyboard.
• TIME (Blue): Displays measurement duration (default 20 seconds), counting down from 20 to 0. The measurement can be stopped early by pressing START or 's' again, but using the full 20 seconds is recommended.
• SAVE RESULT [r] (Red): Saves the measured frequency curve as a PNG file. Press 'r' on the keyboard for convenience.

Visual Description: A detailed screenshot of the ATF Real-Time Analyzer interface is shown, with numbered callouts pointing to the colored bar, frequency values, orange and grey bars, sliders, and control buttons.

Performing Your First Measurement

1. Sit in the driver's seat with the measuring microphone. Place your PC on the passenger seat for easy operation. Ensure the screen is not positioned directly in front of the passenger-side speakers, as this can affect results.
2. Start playback of the "pink noise" test signal on your car radio. Activate the "Repeat" function if available. Adjust the volume so ambient noise is masked and the analyzer's upper bar turns green.
3. Hold the microphone upright and move it slowly and steadily in a semicircle between your left and right ears throughout the measurement.
4. Click the "START" button or press 's' on your keyboard to begin the measurement.
5. The ATF Audio Analyzer will perform a 20-second reading. The resulting frequency response will be displayed with the reference curve.
6. Your first measurement is now complete.

The "Sound Tuning Magazine" provides detailed step-by-step instructions for adjusting your DSP device. The ATF Audio Analyzer is an indispensable tool for achieving significant acoustic improvements.

Warranty Information

The limited warranty complies with legal regulations. Failures or damages caused by overload or improper use are not covered. Return defective products with proof of purchase and a detailed malfunction description. Technical specifications are subject to change.

Mistakes and errors are reserved. Audiotec Fischer is not liable for damages to the vehicle or device caused by handling errors. All Audiotec Fischer products feature a CE-Certification mark.

Contact Information:

Audiotec Fischer GmbH
Gewerbegebiet Lake II · Hünegräben 26 · D-57392 Schmallenberg
Tel.: +49 2972 9788 0 · Fax: +49 2972 9788 88
E-mail: contact@audiotec-fischer.com · Internet: www.audiotec-fischer.com

Related Publication

DSP Spezial Nr. 1 - The Sound Tuning Magazine

This magazine offers tips and tricks for the PC-Tool software and vehicle measurement. It is available as a free download from the Audiotec Fischer homepage: www.audiotec-fischer.com

Visual Description: Images of the magazine covers for "DSP Spezial Nr. 1 - Das Klang-Tuning Magazin" and "DSP Special No. 1 - The sound tuning magazine" are shown, highlighting the content and availability.