So how to judge the quality of the line array? Many people have their own answers to this question, the most common one is to listen to it with their ears. Especially the sound engineer who is used to performing, absolutely believes in his ears!
Outdoor line array speaker display
From the perspective of a R&D engineer and system engineer, we can judge from the following points:
1. Look at the speaker unit size and crossover point
This can already determine a lot of information. For example, if the tweeter is a 44mm diameter tweeter, the safe working frequency cannot be lower than 2K. If the midrange uses four 6-and-a-half inches, you can judge that the design is unreasonable, because The minimum distance between two 6-and-a-half inches horizontally must exceed 7 inches, and the lowest point of interference frequency of 7 inches is about 1.34K (242 formula), so for the safety of the unit, if the crossover point is at 2K, the midrange will be at 1.34K. If interference occurs, in order not to interfere, if the crossover point is 1.3K, the diaphragm of the 44 treble will soon be broken. So it is completely unreasonable design.
2. Look at the impedance curve
Especially for bass, if you design an unreasonable speaker, the impedance curve will be quickly seen. If you design a reasonable speaker according to the unit T/S parameters, the low frequency characteristics will not be bad. If the impedance curve shows that the volume is not enough, or the tuning is low , Or the tuning is too high, or there is resonance, or the volume is too large, the low frequency will not be good. Speakers with poor impedance curves often lack the theoretical knowledge of the designer. In Guangdong speaker factories, copycats are prevailing, and it is difficult for Chinese speakers to enter the European and American markets. One of the reasons is that there is almost no original design, and many people spend a lot of time on it. The original method of trial and error is used to make speakers, and there are few factories that use scientific methods to design professional speakers. This is also the sadness of the industry!
3. Communicate with developers
Before listening to speakers, if speaker developers can't find a factory for communication, it is often COPY products. If the developers themselves are not clear about his design ideas, the speakers are probably not better. The structure of the speaker, how the crossover point is determined, the relationship between the size of each unit and the dynamic headroom of the entire speaker.
4. Have you considered mobile system support?
Many line array speakers are used for mobile performances. If the hanging parts, weight, and handle of the line array are not designed for quick installation, the actual use will inevitably not be able to meet the requirements of the performance. Whether the supporting system cabinet is easy to operate, small in size and light in weight, whether the wiring and power supply in the cabinet are connected properly, is there a dedicated interface on the front of the cabinet for easy connection, and whether the processor has a standard preset program in it? It’s OK not to send the full frequency to the cabinet, whether there is an independent input for the full frequency and ultra-low frequency. Is there a matching rain cover, is there a matching speaker cable, whether the design of the hanger is reasonable and safe (7:1 safety factor, have you done a tensile test), whether it can be suspended at a single point, and the vertical inclination of the array can be adjusted (There is a perforated beam in the middle), whether the transportation package is a flight box or a wheel plate, the locks and wheels of the flight box must be made of reliable and strong materials (the most vulnerable are these two accessories).
5. Whether the parameter curve of the speaker is true
Many factory data have graphs, but is it true? If you can directly test the frequency response and phase curve of the speaker after listening, it is ideal. The phase curve is best to be tested separately. If the high pitch, midrange, The phase curve measured by the bass separation does not overlap at the crossover point, indicating that the speaker processor parameters are unreasonable, and the frequency response cannot be normal near the crossover point.
Measure a curve at a distance of 4 meters from the 4 or more linear arrays on the axis and 45 degrees off the axis (also 4 meters). Observe the difference between the two curves. In the 700-12K frequency band, the two curves are evenly different by about 6DB. It means that the horizontal coverage of this line array is 90 degrees, and the directivity is very good. The microphone is placed on the axis above 50 meters to measure the frequency response, and the high frequency can still be leveled up to 13K, indicating that the speaker has a good high frequency.
It can still be flat at 80 meters until 12K, which means it is a very good speaker. Whether the unit has done an AES power experiment, if the R&D staff can't even tell the method of the AES power experiment, they must have not done a power experiment, then the actual power of the speaker is questionable.