After four months of design and production, the second box of the Rhyme series was finally completed. We named it "Gentleman of Music", hoping that it will have noble quality, rich connotation and rest like a gentleman, so as to obtain the satisfaction of the majority of users. In fact, as early as the completion of the "Le Yun noble", the project of "Le Yun gentleman" has been launched. The design of "Gentleman" is also based on the concept of "low price and high quality". As the second music series product, I hope it is different from the noble style. We hope that it will perform better overall, especially in terms of HIFI and AV, we can have a balance, the price is appropriate, and we also consider a series of problems such as dynamic transmission. Therefore, the box is basically fixed on a large-volume bookcase box.
The design goal of "Gentleman" is to ensure good dynamic effect and sensitivity under the condition of sound balance and HIFI. It is not easy to achieve such an effect. At the same time, it is decided that the unit with a too small caliber cannot be selected on this box, otherwise it will not be easy to get better dynamics and sensitivity. On the other hand, I did not want to make the cabinet too big, so I chose to choose a unit with a larger diameter. After making a compromise, I set the diameter of the mid-bass unit to the 8-inch diameter. There are a lot of units to choose from in the 8-inch caliber, with reference to S, D, and K of HIVI. series. Some T & T models, as well as some engineering samples from manufacturers. In the end we used T & T's 802. The reason is simple, it is the most cost-effective. At the same time, the applicability is also the best. Let's introduce the selection of the unit. Consider some unconventional factors The following will not specify the specific model of the reference product.
The first is one of HIVX's S series, the price is okay, but some parameters can not meet the requirements, mainly due to insufficient rigidity of the diaphragm. It is not easy to get a better and more detailed sound reproduction, and the linear displacement is relatively insufficient, which will affect the reproduction of low frequencies under large dynamics. Of course, this is not to say that it is not good, but only relative. There is also the problem of the axial phase and off-axis response. The peak and valley of this unit's separation vibration at intermediate frequency, and the membrane curve of this unit and the smaller dust cap make it produce a higher front chamber effect. There is a large attenuation valley off-axis. Of course, we cannot ask the manufacturer to put on a large dust cap. Because it will increase the vibration quality, and reduce the rigidity and harmonic distortion caused by the internal cavity, and the magnetic circuit changes, it will bring more disadvantages on the basis of this unit. If you want to use this unit, you will have to lower the crossover point. I do n’t want to be limited by this, so I gave up choosing this unit.
Next, let's talk about another D series unit. First of all, this unit is relatively expensive. Of course, if it is suitable, this will not be a problem. This unit embodies an atmosphere in appearance, and it is also a well-known product in the domestic unit. It has good rigidity and damping in the diaphragm, and has high compliance. The frequency response of the shaft phase and off-axis The deviation of the response is good, and the difference in 2K frequency is controlled within 5DB at an angle of 30 degrees. This is mainly due to the point of its diaphragm. But this unit is relatively low in sensitivity, and the vibration mass is too heavy. The Q value fails to meet the requirements, which will bring difficulties in promotion. It is easy to push the low frequencies too fat and it is easy to make the sound less heavy. Dynamics are not easy to handle. It is difficult to perform well in the transient state. In the end, the unit was abandoned.
Furthermore, there are some engineering samples from some manufacturers. Use PP basin, like plastic folding ring. The appearance is relatively ordinary. The construction cost is cheap, and the overall level is not much different from the above S series products. So no choice. The final focus is still on T & T's 802. T & T ’s products are relatively few users among fans, some fans have less awareness of it, and now the manufacturers ’propaganda methods are more fashionable, and some friends are unavoidable Somewhat disgusting. However, manufacturers must also survive. The problem that this method can become the mainstream explanation cannot be blamed on the manufacturers, as long as they can produce good products. I also use a lot of this unit, some products can be said to have failed, but they cannot be killed with one shot. There will be good products if there are bad ones. This 802 is a good product in my opinion. Of course, we cannot compare it with some very top-level units. It's just relative price. Later in the design, some improvements were made in consultation with the factory. The 802 diaphragm used carbon fiber plus wool basin. High rigidity and good damping characteristics. From the perspective of the diaphragm, this material is very good, and its rigidity is the same as that of SCAN's 8555. But such a diaphragm also brings the vibration quality is unlikely to be too low, the overall vibration quality of the aluminum skeleton voice coil is controlled at 20G. This is not high for an 8-inch unit. At the same time, in order to get higher linear displacement and sensitivity of this unit, thicker washer was used, and if the washer is thicker, it will reduce the magnetic flux density in the magnetic circuit. This will reduce the sensitivity. In order to ensure that the displacement and sensitivity are in place, a larger magnet is used. This ensures that the magnetic flux density reaches 10T and the sensitivity is 90DB. However, in order to control the Q value, this unit is not made too high in compliance. This makes its FO only stay around 45HZ. If it is lower, let it play a lower frequency. But think on the other hand. At low frequencies that are too low under large dynamics, this unit can no longer get a greater gain. So as long as this part is fully utilized, it is enough. Then let's talk about frequency response. Because the rigidity and damping are more appropriate and there is no dust cap. This unit performs well in terms of frequency response, with no large peaks and valleys. In order to prevent the valley caused by the anterior chamber effect within 30 degrees off-axis, an aluminum phase plug is used. At the same time, the dust cap can be removed to reduce the vibration quality. At the same time, the use of pure aluminum phase plug can reduce the harmonic distortion due to resonance. It also looks beautiful in appearance. 802 adopts cast aluminum pot rack, which effectively reduces the harmonic distortion caused by the resonance of the pot rack in large dynamics. Fully guarantee the performance under dynamic. The following is part of the 802 information:
As a box. It can't just be required to have large dynamics and high sensitivity. Balanced and authentic performance under dynamics is equally important. In order to prevent the high-end gain of the large-diameter woofer from appearing too high under dynamic conditions, the sound will have an excessive sense of mid and high frequency bands under dynamic conditions. At the same time, a better transition band is connected to the high frequency. An intermediate frequency unit is used here. On the one hand, I don't want the volume of the box to be too large, and the structure is too complicated, so I gave up the ordinary cone unit and adopted a smaller dome midrange. It is also for this reason that there is a higher requirement for the off-axis response of the woofer described above. On the one hand, the midrange using the dome wants to effectively reduce the distortion, and at the same time it has better transient characteristics, expandability, and detailed sound reproduction. On the other hand, the use of an intermediate frequency unit with an independent rear cavity can effectively reduce the complexity of the cabinet. And volume. In the midrange of the dome, I originally wanted to use one of HIVX, but the price / performance ratio was so bad that I finally gave up, and some of the silver flute products referenced were not suitable. If the sensitivity is not up to the requirements. In the end, the supplier provided a pair of T & T dome midrange. The overall use is quite suitable. And the price is moderate. So don't think about it. This is it. Next, upload the unit diagram and the frequency response of the upper box (has been affected by the diffraction of the baffle).
In terms of treble, there are actually many optional units. The selectivity is large in terms of the size and number of diaphragms. At the same time, the top dome is used, so the lower limit of the treble is lower. In this way, the selectable surface becomes very large. In terms of indicators, many trebles that can be bought can be used. But in order to make good use of and suitable, it requires a lot of work. In addition to a comparison of conventional parameters, it also took a longer time to make a real comparison. See which is best. TT and HIVI have been compared several times, and finally chose 600 T & T. on the one hand. The index is better at the same price, and the sense of hearing is better than the comparison model. The 28mm treble used here was initially too big. Will affect its upper limit frequency. But there are a lot of units that are smaller than it, but the upper limit is not very good, and overall is insufficient. Although the 28MM is too large, it also benefits from the dynamic gain. Simply give full play to the dynamic effect. This unit is used. Finally, it was confirmed in actual listening that the unit's listening sense is fine. This also directly indicates that it is applicable. The photos of this unit and the frequency response of the shaft after loading are uploaded below
In terms of cabinet design, in order to better design the cabinet and closer to the real listening. After getting the 802 for more than a month of aging, before and after aging, the compliance has been improved, and the FO has also decreased. And the parameters are relatively stable before the real design. In the design of volume size and size ratio, we must first make full use of the advantages of the unit and fully expand its low-frequency performance. Because the 802 itself has a low Q and low compliance, there is a certain amount of mechanical damping, so there is less worry about low frequency transients. Give full play to its low-frequency dive, otherwise it will waste its high displacement characteristics. At the same time, it combines the characteristics of FO and the appropriate aspects of promotion. The tuning frequency of the tuning box is designed to be around 50HZ. And fully simulated the proportion of the cabinet and the amount of sound-absorbing cotton added to fully solve the problem of column waves. At the same time, the design parameters of the box body are not affected by the sound-absorbing cotton and the sound velocity in the box is not too large. Because the cabinet as a whole is not small. Strength is an issue that must be considered. Otherwise, the distortion caused by resonance cannot be ignored. The other parts of the human voice sound hollow, and there will always be something missing. On the gentleman, we used a relatively troublesome method and adopted the reinforcement of the word "tian". And all the corners are used to add sleepy bars. This is used to control the strength of the cabinet, especially for the performance of heavy volume under large dynamics. In the phase guide tube, this time the rear guide phase was adopted. On the one hand, the leading phase is not very suitable for this box. On the one hand, the front panel duct will affect the high and high frequencies of the increased barrier diffraction, on the other hand, the modulated wind sound from the duct is not sufficiently attenuated and will be noisy. More importantly, the duct will generate larger airflow. These airflows are straight on the panel. He will directly affect the speed of sound on the front of the cabinet. This directly changes the wavelength of the sound wave. At the same time, this airflow will generate more air vortices on the front panel and will suddenly drop within a certain distance. This will seriously affect the phase and frequency division between the units. Too much deviation from the design goals. Its impact is focused on the mid-high frequency and above, and the more obvious it is in the case of large dynamics, the only way to solve it is to position the catheter as far away as possible from the mid-high unit, and the gentleman is the bookshelf box. There is no other place on the panel, so more options for the post phase. In the design of the gentleman, the dual-conducting phase tube is selected because the wind noise of the duct is reduced. Reduce the eddy current caused by the duct, and the modulation noise caused by the large difference in wind resistance and wind speed, and this will be a serious problem to be considered under large dynamics. Here are some pictures of the cabinet.
Box simulation curve and internal column wave situation etc.
Voltage curve
Impedance simulation
Group delay
Cabinet design lower limit
Design the position of each unit on the baffle board, especially the position of middle and high units. Because both are dome-shaped units, the expansion is better, so the position of the panel must be paid attention to, as far as possible, the control unit is affected by the diffraction of the baffle and the peaks and valleys in the frequency response are too large. In this box, the middle and high frequencies are all centered to mitigate the effects of baffle diffraction. Initially, I wanted to stick sound-absorbing cotton to the panel between the middle and high frequencies. In order to mitigate the interference between the two dome-shaped mid-treble. However, considering that the operating frequency of the two is not the same, the effect is relatively insufficient and it will affect the diffusion, so it is abandoned. The off-center installation unit also brings the sound so that the vertical line is not in a center, which has some effect on the near-field listening. It is relatively small after the far field so it does not matter. Still used. Let's put some fingering and simulation scenes below.
The simulation design of the cabinet has been revised several times, and finally the two sample boxes were modified to finalize the design, which reflects our rigorousness for this box. Then, in the design of frequency division, more solutions are also used. For the third-order sub-band pass, the second-order low-pass is used, and the second-order supplement is used. In terms of frequency division, the lower limit of the midrange unit can not be low. A certain slope must be used to attenuate it. The crossover structure is special. The main design should allow the midrange playback to have a suitable range, and also have sufficient attenuation, otherwise there will be serious distortion under large dynamics and the common crossover architecture is likely to cause Q values ​​on such units. Too high. Therefore, a second-order bandpass is used. Just make some adjustments to the differences in the positions such as LC. The current problem is mainly the low impedance of the midrange. This is also the key to the promotion of this box. In terms of crossover points, 1.7K and 5.9K crossover points were adopted. And fully consider the phase to make it as good as possible. It also verified its integrity in the actual listening in the later period. A pair of JBL boxes were also placed in the listening room. When the listener walked within one meter of the box, he didn't even know which box made the sound. This shows the superiority of the box in terms of sound positioning. Pass the final parameters of some boxes.
Alto Inversion
Finger Frequency Response Multi-axis Plan
This is the final measured overall frequency response and impedance graph
Impedance graph
The gentleman has spent a lot of time from design to completion. It also took us a lot of energy. Our understanding of boxes is incorporated into every product. At the same time the pursuit of high-quality products, rigorous style and design. I believe this box will meet the needs of most friends. There was a JBL box next to this box during the audition. That's a professional box with a price of ten thousand yuan. When we listened to the sound, we used it many times. We replaced the gentleman's box for it. As a result, the listener didn't realize that the sound box had been replaced at the time, and then he realized it after telling the listener. Excessive subjective comments will not be said here. Whether it is good or bad will be evaluated by the majority of users. Although this box has high sensitivity, it is not easy to push. I hope friends who already have this box can spend more time. It will bring you unexpected performance. The first dozens of pairs have all been confirmed, and the response is not bad.
Here are some nominal parameters of this box:
Cabinet Specifications: Bass eight inches, midrange two inches, treble one inch, three-way three-way bookshelf box axis frequency response: 50-20KHZ +/- 3DB
Off-axis 30 degree response: 50-18KHZ +/- 3DB
Rated power range: 120W
Maximum instantaneous power: 250W
Crossover point: 1.7KHZ, 5.9KHZ
Sensitivity: 90dB
Input impedance: 4 ohms Dimensions: height 550; width 295; depth 315
Weight: 40 kg / pair
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