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Subpage: Program: AUDIO-TEST Vers. 2.0

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What is Shareware / Freeware ( in German )

download Audio-Test 2.0 / 06.2004

OS: Win 95/98 ... Win XP

Freeware for private use


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Publication Date: Dec 16th, 2001:

With this program you can check into what extent the loudspeakers or headphones of your music systems fit to your ears or your ears fit to the speakers.

Version 1.0, Dec 2001, Publication

Version 1.20 Feb 2002, (new Method: auto chart; new menu Option: Adjustment )
Version 1.40 Jun 2002, ( autosize of chart )
Version 1.50 Jan 2003, Frequency range up to 16 kHz
Version 1.60 Feb 2004, different port addresses selectable: $0220 ..., $0330, $0530, $D400

Version 2.0 Jun 2004, Windows XP compatible version


www.audio-soft.de


Audio-Test 1.0 / download


green : Standard plot

blue : measured plot

blue points : sampled points


terms of use:

private use: Freeware

Non Profit: Organisations, clubs, institutes ... : on demand

Profit: not allowed or on demand


Example: 1

Example

Using the output method via ports (OS: Win 95/98) a frequency range up to 16 kHz can be tested.

You see a chart that has a drain in the range of 4 - 7 kHz of about 30 dezibel. This chart has been taken up with headphones of a well known manufacturer (Price range about 40,- up to 60,- EUR). A drain of about 30 dB in the range of 5 kHz is as if this frequency would be totally missing ( remaining sound pressure is about 3% compared with adjacent frequency ranges ) This effect has not been observed by the same test person with other headphones.

Remark:

With those kind of "measurements" the question might occur whether the drain is caused by the headphones or by the test persons ear. Comparisons with different headphones and different test persons might give first hints to that.


Restrictions:

Several Port addresses can be selected in menu option: Devices, Methods, Ports.

Instructions:

At first click the START button to check if the sound card is found

Adjustment/Calibration:

Disable the "automatic" button. Set the voume to about 12 dB. Select a frequency of 1 kHz or 3 kHz and set the volume to 12 dezibel. Then take the sound mixer program of your sound card and set the volume as low, as you can hardly hear the sound.

From version 2.0 on you can select the output method "data stream" using the menu option "Devices, Methods, Ports". The initial volume (calibration volume) can be adjusted from 100 % downto 2 %.

Measurement, data logging:

Set the frequency to the max ( 8 kHz ) and press the " = 0 dB " button and press "continue" so that the volume increases automatically. The data logging starts on the left side. The volume increases automatically every 2 seconds by 2 dezibel. As soon as you can hear the sound click the "ok. select" button and the data point is stored. A stored data point is indicated by a blue dot at the appropriate frequency slot (if automatic is disabled). You can repeat the measurement of each point if you click the (-6 dB) or (= 0 dB) button. Press the (<) button and the data point with a lower frequency is selected to be measured. Continue measuring each frequency until all data points on the left side are collected. The dezibel value is not displayed during data logging not to influence your selection. If you want to see the dezibel value during measurement select menu oprtion "volume - display" ( Lautstärke - anzeigen ).
If you have collected every data point on the left side click "sample r" to go to the right side. If you click on "sample r" the chart of the left side is generated.

Hints:

Port Driver to address the OPL sound card synthesizer ports:

Under Windows 95/98 you can address IO ports directly to write to the OPL sound card ports i.e. you need no port drivers (choose Method: direct Port IO). For Windows NT/2000/XP you need port drivers. You can find the port drivers in the internet. If you use port drivers please register your selected drivers as required (see the authors registration conditions)

Alternatively you can use the method "Data Stream" to generate sound output with sampled data stream.

Currently audio-test 2.0 uses drivers of A.Weitzman. You can obtain them e.g. at:

www.torry.net Component -> System -> PortAccess

Using the synthesizer ports for generating sound the frequency range can be selected up to 16 kHz (Win 95/98/ME only). The output method using the OPL synthesizer is not provided with all sound cards initially. May be that you have to install OPL sound drivers.

For instructions/trouble shooting see:

www.creative.com -> Solution ID 339
The scope of 125 Hz to 8 kHz is a standard frequency scope.

The absolute dezibel value of the sampled values ( blue ) in comparison with the standard curve ( green ) does not give a true value, since the measured dezibel value depends also from the sound card and the headphones, but the chart structure should give a first impression about your frequency listening ability. The uncertainity of each single measured point is expected to be in the range of 3 dB. The uncertainity of a data point on different days is ( due to your hearing curve dynanic ) expected to be in the range of 5 dB. A wrong ohm or inductive preresistor can lead to a distortion in the measured hearing curve especialy in the mid and upper frequencay range. ( ask an electronic constructor).

Interpretation:

Audio-Test plots the detected dB values in absolute values ! A different way to plot the detected values is to plot them relatively to the sensitivity of the ear. That means that very low and very high frequencies that cannot be heard very good are shifted up. A tone at e.g. 250 Hz that is normally heard at 20 dB (see green plot) ist ploted at 0 dB and a tone at 250 Hz that is detected at 30 dB is plotted at 10 dB (also 20 dB up).

The relative plot is not supported at version 2.0.

A relative deviation of 10 dB or more from the standard structure or from the right and left datapoints can indicate a hearing curve that needs a correction.

The Dezibel (dB)-Scale ist logarithmic, i.e. a difference of 10 dB is the equivalent of a 3.16 fold difference in noise pressure and a difference of 20 dB is a 10 fold ( 40 dB = 100 fold ) difference in noise pressure.

Dezibel
dB
Relation
U1 : U2 (Pressure)
Relation
P1 : P2 ( Power )
0 1,00 1,00
1 1,12 1,26
2 1,26 1,58
3 1,41 2,00
4 1,58 2,52
6 2,00 4,00
8 2,52 6,31
10 3,16 10,0
15 5,62 31,62
20 10,0 100
30 31,6 1000
40 100 10 000
50 316 100 000

Rule: dB := 20 * log10( U1 : U2 )


Software Hint 2008:

eBioo® - The Brainwave Tuner / 'Chip-Tuning' for Your Brain:


by:



Product hint:

Panasonic ® Shockwave ® Brain Shaker Extreme Headphones have a built in (Piezo-)vibration element.
With this you can measure even so called bone conduction.

Links:

BZgA LuG M 19

audiva.de

Disclaimer:

- see german text version -


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creatred/last updated: Dec 2001 / Jan 2008

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