HOW TO CHOOSE YOUR LOUDSPEAKERS
I will not tell you here what brand of loudspeakers you have to choose, this does is not my point. On the other hand, I would advise you not to buy does anything and, in any case, to take quality speakers suitable for your installation. This is therefore through the technical specifications that I will walk you! Perilous journey in the middle of the Hertz and decibels. My goal is to help you make the right choice in a ruthless world, or the best is next to the worst:
- The enclosure studied with great technical data reinforcement;
- The one made at random, on a corner of table;
- The one, finally, produced at the lowest price, with great blows of compromise.
HOW MANY LANES.
Used alone, a loudspeaker often struggling to cover the entire sound spectrum. Some of them are designed with a secondary membrane, (double cone) to enhance the reproduction of high frequencies, their structures allow them to work on a wide band. This formula, known as a one-way, is permitted for any small enclosures whose response is limited, both in the grave and in the acute but whose equilibrium is maintained. As soon as the size increases, as soon as you wants to pass from the grave, it is necessary to choose a serious high-size HP, which prevents it from radiating effectively in the acute. We move to two lanes by adding a tweeter, still call it a Twitter speaker. has three lanes with, in addition, a loudspeaker specialized in the reproduction of the midrange frequencies and a filter that distributes to the three transducers the frequencies that return to them. I advise you to pay attention to some two-way mini speakers, on which the manufacturer installs a poor quality piezo loudspeaker, directemenl connected in parallel, without any filter, on the main speaker. Two, three, four lanes or more, this is a matter of taste. A two-way enclosure can be excellent and in any case better quibbles a poorly designed one. Generally the three lanes cost more than the two lanes, they have one more speaker and a more complex filter. In fact, the choice will be listened to, but the clutter and aesthetics also play their role. An interesting solution, this is the Triphony, which combines two small speakers working in the medium and the treble, to a subwoofer that works in mono thanks to a two-reel loudspeaker and can be placed does matter or considering The lack of directivity of the bass.
THE FREQUENCY RESPONSE CURVE.
This is this data which best reflects the quality of an enclosure, yet it is necessary to be accompanied by certain details. If you are told that the curve covers a range of frequencies ranging from 1o Hz to 23OOO Hz or from 40 to 18 000 Hz, this does not mean much, it lacks a data: the template inside which if inscribes the response curve. The range of the frequencies reproduced must in fact if accompany the difference, expressed in DB, between the minimum and the maximum of the curve. With equal bandwidth, it is better to have more or less 2 db than more or less 6 db. The curve itself raised in the deaf room gives more indications. Attention however at the scale of the DB: if the latter covers 50 db, it will be more flattering quibbles a scale of 25 db... The curve has the advantage, on an encrypted data, to show possible accidents in the medium, or elsewhere. Do not worry too much, however, because, once at home, the does enclosure will certainly not have the same colour as the one listened to in the store, which usually has at least one wall covered with speakers. For a high-end installation, plan a possible acoustic correction (equalizer). It must however correct the premise and not the enclosure! Too strong, reassembled from the treble in a slightly deaf enclosure can train a partial and selective deafness by deterioration of the tweeter...
An enclosure is also characterized by its impedance, the minimum impedance considered on the whole spectrum. Behind your amplifier There is a nameplate that gives you the impedance to respect. A 4-Ohm enclosure draws more power from the amplifier quibbles an 8-ohm enclosure, it is more demanding when running and the amplifier may not support it. Amps from a certain power (more than 20 Watts), are calculated to work on 4 ohms. I advise you not to connect more than two pairs of loudspeakers to the output of your amplifier. Only one connection formula is valid, which is to place the speakers in parallel; They will both see the internal impedance of the amplifier. Parallel, the conductances if Add. Two 4-Ohm speakers, this is 2 ohms; Two of 8 ohms: 4 ohms. Some amplifiers automatically switch the serialization of the two pairs of HP when both are connected, no risk to the amp, but the sound side, the result does is not terrible, especially if the two pairs of speakers are not identical... Therefore, consult the amplifier's operating instructions. In any case, if you are considering using two pairs of speakers, choose 8 ohm impedance models. Some amplifiers, capable of delivering high current can work smoothly on a 2 ohm load, but this does is not the majority.
Here, two powers are to be considered: the one delivered by the amplifier and the one accepted by the loudspeaker. Today manufacturers tend to announce high speaker powers, these powers are crested. Or musical, that the amplifier can not withstand for long. So Prudence, low power amplifier, powerful speaker? This solution poses a problem: if the amp is weak and the speaker does does not distort, you will tend to push the sound level. The amplifier will clip, distortion creates harmonics, and where do these harmonics go? In the tweeter, a small transducer that cannot withstand big power. risk for the latter. Unless the size of the enclosure in relation to the amp is excessive... On the other hand, if the amplifier is too powerful, you does not hear the distortion, you will push the potentiometer and the diaphragm will exceed their nominal excursion with risk of tearing and, by Joule effect, of (toasting) the reels. So again, caution, unless: the speakers are equipped with a protection system or that: you are planning a fuse (it increases a bit the internal resistance of the connection). Two possible formulas with a disadapted puissonce. The safest, this is the amp a little too powerful for the enclosure, provided not to overdo the acoustic decibel... Third solution, the perfect adaptation of the powers, a risk-free formula if you buy all the choîne at the same time, without predicting evolution over time. Attention however to the channels all made, homogeneous in quality jusqu' to the speakers (often flattering....)
The output is the ratio in the sound power and the electrical power. It if expressed in DB acoustics at 1 Watt reduced to 1 metre, this does not mean much because of the variation of the impedance with the frequency. As the amplifiers are sources of tension, we proceed in another way: we put at the terminals of the enclosure, a voltage of 2.83 volts, which makes us well 1 Watt on 8 ohms. This indication 2.83 volts tends to replace the notion of 1 Watt. As for the distance brought back to 1 metre, it is there to homogenize the results. The measurement is made several meters away, where the distance between the speakers does not create any more interference and, by calculation it is inferred a sound level to 1 meter. High yield or low yield? Does performance is not a quality criterion. A low-output enclosure will give equal amp power.. A lower sound level than the high performance. Numbers: Small enclosures generally have a lower output than large, (86-88 DB per watt). Large speakers see their performance for some models, close to that of the PA loudspeakers, reaching close to 100 DB per watt at 1 metre. The If sound attenuates by 6 DB each time you doubles the distance. With an acoustic speaker so the output is 82 DB, 1 watt per metre, it will take 100 watts to achieve a sound level of 1OO db at 4 meters. With an acoustic loudspeaker with a output of 98 DB, Watt per metre, it will only take 6 Watts! An acoustic enclosure whose performance announced by the manufacturer is 92 DB (this is already a good performance for a Hifi enclosure) will provide sufficient sound power for an apartment with an amplifier delivering 25 W. You know, if you want to sound an apartment, a house, a party room. The does performance has no influence on quality.
The loudspeaker is the most difficult link in the HiFi system to choose from. You should know that listening, once the loudspeaker is made in your apartment, will be different from that in the auditorium: as far as possible and for speakers of a high price, try to get from your dealer quibbles it will allow you D ' Refine your choice between the two or three pairs of speakers you prefer at home. During a comparative listening, make sure that the sound level is the same for the speaker pairs to be compared (calibrating the levels from a noise source, for example a tuner between two stations). The high performance enclosure often seems more flattering... beware!
BUY VINTAGE SPEAKERS.
With the speakers, listening is indispensable and check the condition of the loudspeaker suspensions. It is possible to have the diaphragm redone and even to change an original speaker, but it still needs to be available and that's the whole point! It is necessary to look for speakers in very beautiful state of preservation, famous brand enclosures: JBL, CABASSE, KEF, BOWER WILKINS, ELIPSON, TANNOY, 3 A, CELESTION, etc... And favor the three lanes. If not go your way and head on to new, very big progress has been made on the speakers but it is a matter of budget. Even vintage is a budget!