Air_US_rev_111.qxd 16-12-2004 14:18 Page 41

THE SUBWOOFER & LFE CHANNEL - BACKGROUND INFO

Checking summing phase cancellation

In a basic 2-channel set-up or 5-channel set-up (like the ITU-775) a sub-woofer is not specified and is not required. But making audio production to be played back on consumer equipment, one has to ensure that the mix will sound right in this situation. Many consumer set-ups provide a sub woofer. Hence it is very important to check what the summing of the bass is like. If the program material basically is out of phase, the bass will be cancelled when summed electrically. But this is not the case if the bass signals are reproduced by the main monitors and summed acoustically. A dramatic difference may exist!

Controlling standing waves

It can be very difficult to get two monitors in the right position in order to prevent the excitation of the standing waves. But placing five monitors are even more difficult! Each monitor should play under the same conditions as the others but that is seldom the case.

Three front monitors can normally be placed away from disturbing boundaries to prohibit the excitation of the standing waves. But in small rooms the rear monitors very often are placed in a corner or on a wall. Having the full frequency range reproduced in a monitor like that, there may occur serious problems which results in a poor low frequency sound distribution in the room.

So this is another reason for using bass management. Simply: Only one monitor - the sub woofer - has to be placed in a safe position. The cross-over frequency can be selected to a value just above the problematic frequency range.

The LFE Channel

LFE is short for Low Frequency Enhancement or Low Frequency Effects, the first being the original name but the second being the most correct with regard to its application.

It is also referred to as the .1-channel, which indicates that the frequency range of this channel is only a fraction of the other channels in a multi channel setup. The actual frequency range is 20 Hz to 120 Hz.

When reproduced the signal is gained by 10 dB compared to the main channels. This provides a possibility of reproducing occasional high-level low frequency contents without affecting the general level setting of the main channels.

Leading signals to the LFE channel should be evaluated carefully in each case as not all transmission or reproduction systems may include this channel. In the music mix there is no special reason for using this channel unless you are recording the 1812 Overture with its canons and all that stuff.

Cross-overs

L

C

R

Ls

Rs

Σ Sub

Low Pass

LFE Gain

120 Hz

+10 dB

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Dynaudio pmn manual Subwoofer & LFE Channel Background Info, Cross-overs, Low Pass LFE Gain
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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.
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