Technical data - read and understand
The average user starts his market overview by looking at תמונות
Of systems and system selection according to the design. Of course this has an impact in the choice, and each has his own taste and preference. But after outright denying the systems that look "too bad" and narrowing down the options a bit, you usually move on to the second step which is checking the specifications of the systems.
In many cases it is difficult to understand what the specification says, and as part of this guide we will try to shed some light on the subject. Let's start by reviewing key parameters. And then we will discuss some of the differences between the 2.1-2.0 system in the layout of the specification pages.
Unlike the stereo market,PC The amplifier is usually included in the speaker enclosure. Therefore in many cases the specification for both will be given as one block. However, we will try to separate things, because in this way you can also understand the responsibility of each of the components on the specification of the system and get a complete picture of the various parameters. Opens in the specifications of the amplifier:
Output Power (Supplier) -
Each amplifier has the maximum power it can spend which will be given in wattsWatt
). It is important to understand that this figure is not a magic word, and should be used with extreme caution. First, the measurement atWatt
Should be done atWatt RMS
In order to have real value. Some manufacturers choose to invent their own concepts forWatt
And therefore it is necessary to distinguish between cases and to know that it is forbidden to compare data in different units. Second, the power of the amplifier is also a function of the load at its output. for speaker
A certain power can be double than for speaker
different. We will return to this topic briefly below.
THD - Total Harmonic Distortion (Harmonic distortion) - In an ideal world this figure did not exist, but in reality no amplifier is perfect and each amplifier adds a certain amount of distortion to the sound. Of course we want that distortion to be minimal. A very important point is that measurements can be made under different conditions. Some manufacturers measure the single frequency distortion of 1KHz And with the power of 1W only. Other manufacturers make this measurement over the audio field 20Hz-20KHz And the full power of the system. Other manufacturers choose even more different methods. It is important to pay attention to the conditions under which the measurement is carried out, since with the increase in power and frequency, the distortions will increase.
Frequency Response (Frequency range) - Each amplifier has a limit on the frequencies it can amplify. The most common method for measuring this field is measuring the amplitude of the frequency 1KHz, And then change the frequency up and down until you find the upper limit and the lower limit where the amplification decreases by3db In relation to the amplifier frequency of1KHz. Choosing the3db Is because the meaning of this number is that the power is 2 smaller. Some manufacturers are more stringent in their tests (allowing for a smaller change in the amplifier), and other manufacturers are more liberal in their tests. For this reason, it is worth noting the conditions in which the measurement was made.
|Watt Watt Wattim
SNR - Signal-to-Noise Ratio (Signal to noise ratio) - This figure measures the ratio between the amplified signal power at output and the output noise power. The lower the amplifier, the higher the number.
Input Sensitivity (Input sensitivity) - Each amplifier has an input voltage required to provide output at maximum power output. If the signal at the input is lower than this value, the output power of the amplifier will be lower than the declared value on the specification sheet.
crosstalk (Leakage) - This index examines the amount of leakage that exists in the amplifier between the two channels. The leakage is always to some extent due to the use of common components for both channels in the amplifier.
There are other parameters that characterize amplifiers, but they are more advanced, and we will never meet them in the specification of audio systems toPC (In most of them we will not meet some of the parameters already examined). Now go to the specifications of the speakers:
Maximm Power (Maximum power) -
to all speaker
There is maximum power indicated on it. Usually this power indicates the maximum that the speaker can be operated without causing damage. Many manufacturers choose to list this suppliershort term
. This means that the speaker can survive for a short time (usually a fraction of a second), before it is damaged. We strongly recommend that you not turn on or even close the speakers on this power.
Impedance (Inhibition) -
to all speaker
There is its electrical impedance. The speaker specification usually contains a data such as 8ohm nominal
, Or simply 8ohm
(Other typical numbers are 6ohm
). Most specifications indicate the impedance (electrical resistance for a frequency other than0Hz
) In the frequency of 1KHz
. The reason we are concerned is that a lower impedance will require the amplifier to have a higher current and lower voltage to provide the same power, and usually an average amplifier will have trouble supplying high currents. But this figure does not tell the truth. This is because the delay of speaker
Can vary significantly as a function of frequency, and at low frequencies can fall to a fraction of the nominal value (eg,8ohm
Up to a value of 2ohm
And even below all). Some readers have noticed that in the car audio systems, for example, the subwoofer impedance is 2ohm
And even below. The reason is that the voltage vehicle operating is 12V
And therefore, in order to provide high power, a low impedance is required that will consume high current at low voltage.
Frequency Response (Frequency range) - Like the equivalent of the amplifiers, the speakers are limited (and generally more severe) in the ability to repeat their frequencies.
Sensitivity (Sensitivity) -
This figure describes the volume that will be output at the output for a particular input signal. It is generally customary to measure the output signal strength atdb
A meter away from the speaker for an entry signal 1Watt
At the frequency of 1KHz
. Yes, many. However, there are also other measures (eg,1Watt
- For those who know the Ohm Law it is easy to understand that for the impediment of 8ohm
Both measurements are equivalent). It is important to understand that this figure has a decisive effect on the volume obtained at the output. As we explained, power is required 2 to obtain an output of 3db
. So for the production of the power of 95db
At the speaker output, speaker
With efficiency of 95db / W
8 will require less power from the amplifier to the front speaker
With efficiency of 87db / W
. When looking at the 1W
It may not deter, but when you look at 25W
Understand the meaning much more.
Size (Size) - This refers not to the physical size of the speaker but to the physical size of the elements included in it. Usually the reading is of the diameter of the element (diameter), And reading is usually given in inches.
Of course, the speakers also have additional parameters, but they are not relevant to us at the moment.
As we mentioned earlier, audio-PC Usually the amplifier and speakers are combined together. For this reason many data are "swallowed" in other data, and some points are not relevant at all for the user as he is not required to match between the speakers and the amplifier. For example, a system that is indicated on the collection that it provides 15W The channel (left channel and right channel for example) means that the amplifier is capable of providing 15W At most. It is important to note that if additional information is not provided, it is very difficult to infer from this the amplifier's power or the volume at the output of the system.
Now we have the knowledge necessary to read most of the specification pages in the market we can do so much more intelligently and not fall into the traps that many manufacturers plant.
When we examine 2.1 system parameters against the 2.0 system, there are some notable differences. First for the 2.1 system, there is always a specification for the stereo speakers (in combination with their amplifiers) and for the bass unit (combined with its amplifier). The main differences that can be noticed beyond that is the size of the element which the speakers and racks will usually have 5.25
Inch and higher (although there are exceptions with Drivens' s) 4
Inch), for bass, and Twitter for high frequencies;
While on the speakers the elemental statins will be of 4"
And sometimes will be the only element without any Twitter
The bass unit usually has a unit of 4" And above which is intended only for the recovery of bass frequencies. As a result of the size of the elements, the 2.0 system will usually have a frequency range of50Hz-20KHz When the entire range of frequencies comes from the pair of speakers. On the other hand, in the 2.1 system it seems that the frequency band is about the same 40Hz-160Hz For the Bass-and-160Hz-20KHz For the stereo speakers.
|Shelves in front of Stalletti