LINE-UP & Calibration Background Info

Dynaudio pmn LINE-UP & Calibration Background Info, Calibration of 5.1 in an ITU-775 arrangement

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LINE-UP & CALIBRATION - BACKGROUND INFO

Calibration of 5.1 in an ITU-775 arrangement

In a 5.1 system based on the ITU arrangement, all main channels have in principle the same conditions: there is one monitor per channel and each is placed the same distance from the listener. Internationally, there is however neither agreement on the level nor on the bandwidth for the noise signals that is used for acoustic calibration. Pink noise is good since it includes all frequencies, however it is impractical due to its "unsettled" character, which makes it difficult to measure at low frequencies.

Surround Sound Forum

Surround Sound Forum is a German interest group composed of the VDT (sound technicians), the IRT and the SRT. The SSF has prepared guidelines, which are generally accepted in Europe. Three test signals are specified in it, which are recorded at -18 dBFS (RMS).


	Measurement Signals				Listening Level

Signal		PPM level	PPM level	RMS level		Sound pressure	Sound pressure
(only in one channel)		t <0,1 ms	t <10 ms			level		level
						SLOW		SLOW
		[dB]	[dB]	[dB]		[dB]		[dB(A)]
1 kHz sine		-18	-18	-18
Pink noise 20 Hz-20 kHz		-9	-13	-18		82	78
Pink noise 200 Hz-20 kHz		-11	-15	-20		80	78

SMPTE

The corresponding standard from SMPTE (RP155) uses a standard of -20 dBFS for the reference level. Here, the C- weighted sound pressure level of a 500 to 2 kHz noise signal ends up at 83 dB.

Calibration of cinema systems

In a cinema, the listeners are sitting far from the monitors. Presumably, the majority sits in the diffuse sound field. In any event, attempts are made to establish a diffuse sound field from the surround monitors. Hence when the sound pressure is measured inside the cinema or in a mixing theatre it must be averaged over many different measurement locations. The typical basis for the majority of the standards is at least four locations. If there are different areas for the audience, for example main floor and balcony, measurement should be made in at least four locations in each. Before this measurement can be performed, the system's frequency response must also be in order.

How to measure the sound pressure?

Sound level meter or microphone

If you are used to perform acoustic measurements you probably already own a sound level meter. This can be used for the level calibration of the monitors.

If you do not have a sound level meter, there still is another possibility:

Take an omni-directional microphone. (This is also called a pressure microphone). A studio condenser microphone is normally preferred but the microphone must not be too big. Then a simple clip microphone can be used instead as it

does not influence the sound field. The microphone should have a flat frequency response.

Place the microphone on a stand positioned at the listening seat. Leave the microphone pointing upwards in order to avoid sound pressure build-up in front of the diaphragm and to provide equal conditions to monitors in all directions.

Connect the microphone to a mixing desk or a recording machine that has a meter built in.

Play back a track containing pink noise on the CD you got with the monitors. (or use one of the other tracks as instructed to during set-up and calibration.

Adjust the gain in the microphone channel until the meter deflection reaches a point 10 dB below full scale. This is now your reference for your measurements. Be sure that you have marks on the scale that makes it possible to read steps of 1 or 2 dB on either side of the reference deflection. If 10 dB below full scale is not an adequate point on your meter you may choose another one, just be sure to have a reading on a adequate resolution.

If you use this microphone set-up as described, it can be used for the level comparison between the individual monitors.

Absolute sound pressure levels can be measured if you:

a)are using a well calibrated microphone channel

b)know the sensitivity of the microphone.

pmn specifications

Dynaudio, a company renowned for its high-fidelity audio products, has made significant strides in the field of professional monitoring through its PPM (Professional Precision Monitoring) series. Among the standout models in this series is the Dynaudio PMN (Professional Monitoring Nearfield), which has garnered attention for its outstanding sound quality, precise technical performance, and sophisticated design.

One of the key features of the Dynaudio PMN monitors is their advanced driver technology. Equipped with proprietary drivers, the PMN series employs custom-designed woofers and tweeters that deliver an incredibly accurate frequency response. The woofers utilize a lightweight diaphragm, ensuring that low frequencies are produced with power while maintaining clarity. The tweeters, known for their soft dome design, excel in reproducing high frequencies with exquisite detail and minimal distortion, making the listening experience both immersive and enjoyable.

In terms of design, the PMN monitors boast a sleek and modern aesthetic that fits seamlessly into any studio environment. The cabinet construction employs advanced materials and techniques that minimize resonance, thus reducing unwanted coloration in sound. The unique curved shape of the cabinets is not only visually appealing but also supports optimal acoustic performance by enhancing sound dispersion.

Another notable characteristic of the Dynaudio PMN is its versatility. The monitors are equipped with multiple inputs, allowing for seamless integration into various set-ups, whether in a professional studio or a home listening environment. This flexibility is further complemented by adjustable bass and treble controls, empowering users to tailor the sound profile to their specific requirements.

Dynaudio has also incorporated advanced technologies such as room correction in certain PMN models, which enables precise calibration according to the acoustics of the room. This feature ensures that audio professionals can rely on consistent and accurate sound reproduction regardless of their monitoring environment.

Overall, the Dynaudio PMN series represents a blend of pioneering audio technology, meticulous craftsmanship, and user-focused design. For professionals seeking precise monitoring solutions for music production, film scoring, or any audio-related projects, the Dynaudio PMN monitors provide an exceptional listening experience that stands the test of time. With their stellar performance and innovative features, these monitors have become a top choice for sound engineers, musicians, and audio enthusiasts alike.