The ATB Quality Control program has been used for 18 years all over the world.

 Here are the specifications of the new version:

 -The program works with the soundcard of the PC.

 -Setting of the definition without script, there is no need of learning to program.

 -Reference curve is measured in the comfortable ATB PC Program.

 -Tolerance field is easy to set automatically or with the mouse.

 -Rub&Buss is tested with the signal 13 to get a nonlinear distortion measurement.

 -Surrounded noise does not disturb the Rub&Buss measurement because of the Q-Index calculation.

The QC program is for the speaker industry for an automatic quality test.
It is also for the automotive industry to test mounting of the speakers for undisturbed music reproduction.
The test systems consist of the ATB QC program, the PC with a soundcard and a test box with a power amplifier for the connection of the speaker.
There are several measurements in the test cycle. For the automatically passed or failed decision, each measurement has its own tolerance mask.
One test cycle can include up to four measurements. These are the acoustic or electrical frequency response and three Rub&Buss measurements for woofer, mid and tweeter.
The frequency response is tested with the M-PN stimulus. For the automatical and manual setting of the tolerance mask there is no need of an uncomfortable script.
The Rub&Buss measurement tests the distortion and noise of the speaker. The stimulus for measurement is the signal 13. The Signal 13 is a combination of two sine waves with the frequency ratio of 1:1,3. This ratio makes that the signal is very good for the test of resonance. The signal also avoids the main problem of the acoustic Rub&Buss measurement. It is the surrounding noise that normally disturbs the measurement. For the passed and failed decision there is the Q-index. The Q-Index includes all distortion and noise of the speaker.
For reporting and documentation the program writes a protocol file.

Frequency response

The frequency response is tested with the M-PN signal. The measurement with this periodic noise gives the highest accuracy.
The tolerance mask can be set automatically or manually.

The picture shows the impedance test of a speaker for the test of the Thiele-Small parameter

The picture shows the frequency response test of a speaker

For the definition of the tolerance mask the frequency range and the upper and lower tolerance curve is set in.
For the automatic setting the program calculates the tolerance curves. This tolerance mask is for the electrical measurement.
For the manual setting the tolerance curves are set with the mouse click. This tolerance mask is for the acoustic measurement.

The Rub&Buss measurement

The Rub&Buss is tested with the signal 13. The signal 13 consists of two sine-sweeps with the frequency ratio of 1 : 1.3. This signal is showing all resonances of the unit under test.

Electrical test of the signal 13

Test of a broken speaker

For the passed and failed decision the Q-Index is calculated. The index is calculated from all frequencies higher than the second frequency of the test signal 13. The account is set into proportion to the amplitude of the test signal. The best speaker has the highest Q-index.

The Rub&Buss measurement has following tests.