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2 years ago
Acoustics for background scoring of rooms

In the fifteenth release of the show "Sound" we speak about acoustics for rooms, the different myths connected with this In more detail about a podcastTo listen to this releasesubject [] [].

Transcripts of other transfers

Dmitry Kabanov: We discussed different aspects of a postscoring of rooms already earlier and did it in the winter when discussed the water-proof columns steady against snow loss. Already almost fall, the rain went, and it is worth returning to this subject.

Timofey Shikolenkov: Good subject. But before we will talk about a related topic which is with us every day – we will talk about the equipment, a sound in public places. Coming to the bar, occasionally you see a magnitofonchik, almost cassette center on a rack, plays radio. There are cases: you come to recently opened institution in which did beautiful repair and at the same time purchased some unclear equipment and put on a rack. This strangeness always surprised me.

The second thing which surprises, however, less often: in some rooms where ceiling columns are usually used – on big spaces they practically do not take the place and do a uniform postscoring – instead of the special built-in speaker systems put automobile loudspeakers.

Dmitry: Understood that on a shelf it is not necessary to put the tape recorder, purchased some center 5.1, 2.1 and decided to distribute all this on corners on a ceiling.

Timofey: I saw even situations when [in public rooms] put the automobile radio tape recorder with the transformer and brought wires to the automobile columns located on a ceiling. People do not understand that automobile speaker systems are intended for that volume which contains in itself(himself) the car body.

It is important to understand that for each speaker system very important factor is an acoustic design, that is in what box, the body it is.

Dmitry: I represent a cafe the size about an average sedan. It would be exciting to sit.

Timofey: It is improbable. People try to invent the bicycle. Probably, they are guided by the fact that a professional equipment, and the word "professional" always frightens all expensive. Professional speaker systems which are intended for a postscoring, a background music cost little.

There are such versions of speaker systems: the small column, ceiling or wall, costs about one thousand rubles. To it the amplifier is necessary. In such cases usually use hybrid devices, a mixer amplifiers. It is one box which can be put in a rack or other convenient place.

Acoustics for background scoring of rooms

Professional active acoustics of Eurosound ES-5A

The professional equipment is intended for work 24/7 – round the clock throughout a progressive tense. The household audio equipment is not expected such use, is not able and should not work so. It has certain, a deadline of service and operating conditions.
At the same time the amplifier is necessary anyway. Perhaps the automobile equipment to people seems to the most familiar and [therefore] they put it.

The situation when in office buy the [home] printer intended for the small volume of printing is similar and print on it all day long. During guaranty period the printer breaks, and workers do not understand what occurred. It is good still that during guaranty period, but not for days later. The device is not intended for operation in such mode.

Returning to an audio subject: the economic aspect is unclear, it is not justified. The same automobile radio tape recorder costs money, it needs to be adapted even for work out of the car.

Dmitry: She will be dearer, and her it is necessary to fix, and it is not provided by construction.

Timofey: On money the same will turn out. Questions of reliability, stability of work, volume are important too. Long ago wanted to talk about volume. All like to measure volume in Watts though it is a power unit of measure. And people think that by what the big digit is written on a column or the amplifier, that is louder.

Of course, these values are to some extent combined among themselves, but volume is measured not in Watts. Volume is measured in Decibels - it is sound pressure. It is primary value in which volume is measured.

In a professional equipment in the description of characteristics of speaker systems sound pressure is always specified. It is very important. For understanding of what digits can be specified there: ten decibels are a low whisper, a rustle of leaves, fifty decibels – sound pressure which we create at quiet conversation.

In earphones or columns sound pressure another. Seventy-seventy five decibels are a shout, ninety decibels – the subway car by us passes. Hundred twenty decibels – a pain threshold, more people can not take out.

If we want to sound the room in which people sit and work, it has to be the gentle music. If it is the warning system … in English there is such phrase "public address", it can try to be translated into Russian as "broadcasting", "broadcasting", "warning system". Just in Russian there is no such phrase.

Acoustics for background scoring of rooms

Wall loudspeaker of APart SPH20

Dmitry: It is probably such system what was earlier at the [western] universities when some declaration joins or the local local radio station is broadcast. Something in such spirit.

Timofey: It the same, as room radio receiving stations, that is sockets which join a loudspeaker. Returning to power: it is more than 85 decibels indoors where people who need to be notified sit, should not be, and music has to be even more silent. In professional acoustics sound pressure at distance 1 meter usually is specified at the power of 1 Watt.

We pass to power. If we take small ceiling or wall columns in which the maximum sound pressure – 92 decibels, that is are more, than it is necessary for us, then it turns out that at 1 Watt we will already receive what is necessary.

Dmitry: It turns out that does not need to be bought amplifiers on 100 Watts and to spend for it a lot of money.

Timofey: There is the second question: why such equipment is recommended to be used? It is very simple to calculate power. If on the amplifier power is specified, for example, 100 W, it mean that we can connect to him hundred 1 W columns. In a professional equipment marketing "features" are seldom applied. "Attributed excess zero, and at once all ran to buy, such loud, such powerful", – it is not there.

If on the Public address systems it is written that the power of a column 2 or 3 of W, 5 or 20 W, so so it also is. The column is expected such power which will be given from the amplifier. Volume depends on the room and distance – we already spoke it.

One more benefit of such systems: these systems allow to use rather long cables, it is possible to transmit a sound on long distances – several hundred meters. Something turns out average: on the one hand professional application, on the other hand – not absolutely household.

Acoustics for background scoring of rooms

The built-in acoustics of Apart CMSQ108

Dmitry: Considering that the cable is put on walls, and the room can be big, the postscoring of fifty square meters will demand tens of meters of a cable.

Timofey: Of course, and it is very convenient. Why? Traditional Hi-Fi of system demand to stretch the separate cable to each column, it is a reality. In a case with the Public address systems of it it is not required. It is possible to connect in parallel a large number of columns, so much, how many it is necessary.

It is interesting that on such columns there is a power switch, that is, conditionally, the volume control for each column. In the bar, restaurant where there is a cash desk, it is necessary that sounding was more silent, at the same time columns can be identical.

Dmitry: It is possible to limit physically [the power given] on these columns …

Timofey: Yes, on these columns without some adjustments in the amplifier. And on the amplifier there is the general volume control and, respectively, in some zones we can make more silent, in some – is louder. Power which should be calculated, proceeding from opportunities of the amplifier will change at the same time.

It is good to make a small stock of power that the amplifier worked not at a limit. If we buy 35 Watt, 50 Watt amplifier, then these are real and sufficient digits, we already discussed it.

Dmitry: Let's talk about the prices.

Timofey: A mixer amplifier – the hybrid device which at once with the volume control and the amplifier, with power about 35-50 Watts, costs within ten thousand rubles. There are more "fancy" devices and absolutely hybrid devices which are on sale together with a source. As a rule, acts as a source or the computer which stands nearby, or some player. The main objective is to find object, where to include a sound source.

Acoustics for background scoring of rooms

APart MA35 mixer amplifier

Dmitry: We can physically limit power on certain columns and if we have any old systems from the fact that we already used, for example, the old audio system whether we can partially involve these columns besides that we buy in addition?

Timofey: By no means. Because the main difference of these systems that they increase amplitude approximately five times by transfer. That is in the amplifier there is a step-up transformer, and no Hi-Fi and not Hi-Fi, that is normal household speaker systems are expected it.

In columns there is a reducing transformer, and the loudspeaker does not work in the extreme mode. If to connect normal columns which are not expected it any time they will work at a limit and quickly enough will fail. There is no need to use such options. One column for such professional system can cost about one thousand rubles. Good costs two thousand rubles, very good – three-four thousand.

They can be different power, but if it is a background rear-fill, then, as a rule, it is systems ceiling or wall. Everything depends on how them to locate indoors. The option of street system is possible, and all this is connected to one amplifier.

Dmitry: If we take small cafe - it is 50-70 thousand rubles for all equipment?

Timofey: No. Twenty, at most thirty thousand rubles and if we want to construct something superqualitative. If to do just background sound, then it is possible to be limited to twenty thousand, including moisture-proof speaker systems on a verandah. It is strange that people try to solve a problem in the difficult ways while there is a solution which costs absolutely not much, and most important, simple in installation.

The inexpensive cable undertakes, it is put along a wall, in the right place the gap becomes, the column which in this place is put is connected. It is possible to add columns in any place if there is a cable stock. It is not necessary to pull hundred cables to hundred columns. All this very simple, convenient and long-lasting.

Dmitry: Whether there is a sense to think of wireless solutions?

Timofey: No. Wireless solutions exist, but they are household. It means that they are not expected long work.

Dmitry: We dealt with a case of small cafe. If we have an average and is closer to large cafe, then we can observe there separation into two, three segments where, including some mini-scene for microperformances can be used.

Timofey: Yes, so often happens as all these systems and a mixer amplifiers, as a rule, multichannel. Is, of course, single-channel and them there is a lot of, expected several zones.

At the same time it is possible to regulate also volume and to connect the microphone. Naturally, all of them go with microphone inputs: with one, two, three, four, different sources. It is possible to send different sources to different zones. All this, besides, becomes once and further is controlled in one place one simple device.

Dmitry: If necessary it is possible to display in the most distant corner and a zone a sound which goes from the microphone from the one who performs, or on the contrary to clean this sound and to direct there music which does not prevent people to enjoy what they do.

Timofey: The main thing that these planned zones from the very beginning were connected to the amplifier on different outputs, that is outputs of different zones. If we initially made only one zone, then it is not necessary to hope that columns will understand what sound to them to reproduce.

When we speak about execution, about a live sound, such systems are no good. As a rule, if we speak about restaurants and bars, then for the scenic equipment other equipment – mixers, scenic big professional speaker systems is used. In institutions in which there is at the same time day rear-fill, and in the evening – a scene, perhaps the disco, live execution, are used two systems.

First, it is Public address, that is a rear-fill in the afternoon, and in the evening – powerful professional acoustics, to bark it is possible to connect musical instruments. Such here hybrid.

Dmitry: If to compare to small cafe as far as this solution will be more expensive?

Timofey: Depends on that how there are more speaker systems how different are necessary sources, for example, simple amplifiers it is possible to separate on zones. To take the microphone: there is a background music which plays everywhere, and there is an automatic function of muting of music at the beginning of some notification as soon as you begin to speak in the microphone. As a rule, all this.

If it is necessary to make something more, then it is possible to put two a mixer amplifier and to make two separate systems. There is multizone, more serious a mixer amplifiers or separately amplifiers and mixers. The scope for creativity is unlimited. Everything depends on a task. The main message which I wanted to make for our listeners consists that it is very simple.

My acquaintance, opening cafe, asked me for the help in area of a sound. In an evening all of us made. More time left on drilling of openings in walls to fix wall loudspeakers. The cable was laid very quickly where it is necessary connected columns.

Dmitry: Main output: "professional" – does not mean that expensive, it means – necessary to work, and not such difficult – to assemble not the rocket.

Timofey: As for professional – in this sphere is "professional", means "cheap". Also it is necessary to understand that the equipment very different and if the column is similar to a column, then it does not mean that it will be suitable for any task. Tasks are different, and there is a lot of them.

And if we know what equipment is suitable for what tasks, then we easily solve them, without spending a lot of money, putting in the future because it will long work, without demanding service. It both reliability, and quality, and reasonable expenditure of money that all is also looked for.

Dmitry: There are still questions which are often asked by those who want to be engaged in it?

Timofey: It is possible to talk about street things to talk.

Dmitry: What to do in the fall and in the winter?

Timofey: Happens so that people buy moisture-proof loudspeakers, and they are very different. There is a standard which describes what amount of moisture can get on speaker systems.

There was a case when the client with a wish to set columns in the pool in water came. It was not succeeded to find out from it why it because nothing will be heard. Unfortunately, could not help it.

And in general, there are different classes and it is necessary to understand that if it hangs on the street under a roof, and it will be the wet environment, directly water will not flow, it is one system if absolutely open space – other system if a sauna with absolute humidity – the third system.

Acoustics for background scoring of rooms

Moisture-proof Visaton FRS 10 WP/8 loudspeaker

Dmitry: There is a class of protection against moisture to which it is necessary to pay attention.

Timofey: It is necessary to look in the description for what application this acoustics is used.

Dmitry: If to remember systems which look in the form of floor stones and other. As far as it should be applied on the street?

Timofey: There are such very interesting and beautiful landscape solutions. It is necessary to read attentively for what they are applications, external or internal. If the column looks as a beautiful pebble, then it does not mean that it can be put on a track. It is necessary to look what class protection against moisture.

If it is supposed that the column will be put in the lowland, then the equipment has to be the corresponding class, or it is necessary to be reoriented and put a column to other place. Essentially nothing will change, plus or minus a half-meter – it is not really important, and the system will be more long-lasting.

Dmitry: Whether there are moments on shock resistance? Accidental contacts with furniture? People can touch something?

Timofey: Is not present, as a rule, everything is built in a ceiling or hung up on walls or on corners. It is difficult to apply shock resistance here. Speaker systems are made of plastic with different elements, it is impossible to beat them with fists, of course.

This article is a translation of the original post at geektimes.ru/post/264330/
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