IEC 268-1 PDF

Sound system equipment – Part 1: General – SS-IEC Buy SS IEC Ed. 1 () Sound System Equipment – Part 1: General from SAI Global. Hi, I am reading a tech note named “The Loudspeaker Toster” by Pat Brown of Synergetic Audio Concepts and I would like to know what the.

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The proposal by R.

I have not found any BS British Standards which play a primary irc in this field. The first few pages are available as a preview.

They may also be of interest for any other source of noise which may be present in a system, in combination with any or all of the above: Responds quickly to brief signals. Some quotes from Section 3 on self-noise: OecWilms and Hertz The filter reduces the input noise voltage by approximately 31 db.

Standard – Sound system equipment – Part 1: General SS-IEC –

While not originally envisaged for the purpose, the method has also been used to measure and compare noise levels on optical sound tracks. From this it can be concluded, however, that the NIESE weighting may get some importance again, when the electronic circuitry is further developed, economic solutions and general experience in the use of Rec. This is cited in Wilms as: Flutter A related question of trying to measure audio impairment in a way which reflects human subjective experience concerns flutter rapid pitch variation.

Only if these conditions are met does any method stand a iiec of being accepted and used widely, regardless of the degree of official standardization. Belger establishes the importance of peak detection, with carefully chosen rise and fall times for the capacitor which is charged by the peak detector, together with the choice of a suitable weighting curve audio filter.

IEC 1st iex, on microphones, is released. Stephan Peus’ paper “Measurements on Studio Microphones” Stephan Peus Neumann wrote a paper [ Peus ] which includes a history of noise measurement standards, with particular reference to using these to determine the equivalent acoustic noise level of microphones.


As a result of the stronger weighting of noise spectrum iex 1. Note that the commonly used integration time of approximately ms is similar to that of the VU meter, although the VU meter reading is sound pressure proportional rather than sound power proportional.

It denotes a particular standard within a larger set of standards. In June I was delighted to receive an English translation of this important paper – follow the above link to the references section. It is stated by the OIRT to be based on “numerous studies” of which, iev, no details were given.


This paper argued against the adoption of: The first peak can be seen in Figure 3 below, in which RMS noise is plotted against voltage from the bias voltage source into the An international standard is still under consideration [ WG ]. I have not seen this, but I am reliably informed that in the section called at least in the 3rd edition “Equivalent sound pressure level due to inherent noise” that the quasi-peak method is now the required method of measurement.

Since the numbers produced by the two systems will not be the same for any one noise signal, this would lead to further confusion for everyone.

The B weighting network is based on the approximate response of the ear at 70 db. Thus, we see that there is a discrepancy between these two international standards: In practice, if white noise is used with a bandwidth of 15 kHz, the following differences in the 26-1 results [ Jakubowski ] are obtained: Iiec English translation of this important paper was kindly provided in February by Harvey A.

According to Weeksin the second edition, a specific quasi-peak detector behaviour was “first completely specified”. Nevertheless, the CCIR decided already in unanimously in favour of quasipeak value measurements for the following reasons see Report They mention three standards regarding noise measurement see years above for more details: See the section below for a depiction of this curve. So, for generating a 268- reading from multiple seconds of audio, perhaps we should simply take the average of the first section.

Belger joined the Nordwestdeutscher Rundfunk in Hamburg as a development engineer. It has apparently not been possible to give a mathematical expression for the transfer function of the Quasi Peak rectifier together with the weighting curve.


Sound system equipment – Part 1: General

The curve which kec IEC prepared for purely acoustical purposes, namely for the loudness of noise background noise, interfering noisethe so-called curve A proved to be unsuitable because when weighting electroacoustical transmissions or recordings, annoyance as well as masking effects are far more predominant.

The situation is another one, when due to unsufficient quality of transmission paths e.

This field is also important to the IEC standard on microphoneswhich as of the 4th edition adopts quasi-peak noise detection as the mandatory method of measuring the inherent self-noise of microphones: Please see Steudel for a graphic scan of this article, which I received in June and for the English translation, which I received in February Considering that presently no international unified reference listening equipment exists and hence the frequency response of the sound pressure is not defined at the listener’s place, the frequency weighting curve for noise voltage measurements should suitably be related to a frequency-independent sound pressure.

The measurement of noise voltage is “the most essential part” of C’s work. There is a new German standard, DIN 45Part 2 for an impulse sound level meter which better corresponds to the impulse response of the ear.

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IEC 3rd edition microphones is released. IEC 2nd edition is released, using the same weighting curve “Q” in Wilms and the same quasi-peak metering circuit as was then specified in CCIR Use of an RMS meter,which does not conform to the standard, produces measuring results which are about 4 dB lower, and therefore apparently better.

This system is very satisfactory technically and for research purposes, but retains the other disadvantages of the DIN method; it uses the same expensive quasi-peak instrument and gives figures apparently inferior to those being published in the specifications of audio products by 10 or 12 dB. Dick Cappels’ project pages http: