Jack raised the pole, and Li Kangping moved to the "tape recorder".

Li Kangping gave a technical explanation according to his hypothetical equipment: "The dual-system camera equipment means that the picture is shot with a camera, and the sound is recorded by a tape recorder. You can understand that the picture and sound are recorded on two different materials at the same time, the picture is recorded by optical film, and the sound is recorded by the magnetic material of the tape recorder. ”

Walt Disney stared at the wooden box "Tape Recorder" and he asked, "This box ...... I mean a 'tape recorder' is a device that specializes in recording sound, what is the difference between it and a phonograph? ”

Li Kangping smiled: "I told Jack that sound film technology is actually a synthesis of many known technologies, Walter, you can understand it for the time being, the tape recorder and the gramophone are similar devices." So, the biggest technical problem in dual-system recording is how to achieve sound and picture synchronization? ”

"That's how I came up with the idea of connecting a sync cable between the camera and the recorder, and that's it, this rope. The camera is powered by a battery-powered motor that is mechanically paced at 24 frames per second. We installed a signal generator on the motor, and when the camera was running at 24 bars per second, the generator emitted a signal at a certain frequency, and the synchronization signal was sent from the camera to the tape recorder through the sync cable and recorded on the magnetic material......"

Li Kangping explained the pickup process of the same recording in as concise and understandable language as possible, and Walter nodded frequently, and he seemed to understand.

"Whether it's a single system or a dual system, post-production sound and picture processing is required. Now, let me talk briefly about the cocktail party effect: the human ear has the ability to distinguish what it wants to hear from multiple sounds, such as in a noisy cocktail party--- we have all been to this kind of drinking party, and Hollywood has a drinking party every day. At a cocktail party, where there are many people talking, the human ear can pick out the sound they want to hear and focus it, even though the volume of this sound may be lower than the volume of the surrounding sound, the human ear can automatically block out the surrounding sounds. ”

However, the microphone does not have the selective recognition function of the human ear, and within the range covered by the directivity of the microphone, it can only pick up all sounds without choice. So, just like the picture, the sound needs to be post-processed. Walter, take us to the editing room. ”

Everyone left the studio and went to the editing room. Here are some editing equipment, and the editing equipment for cartoons is much the same as that for live-action films.

Walt Disney explained the post-editing process for silent films: "In fact, many editors rely on the creator's intuition, and the functions of editing include scene changes, time compression and omission, splitting, parallelism, and contrast......

Walt Disney demonstrated the editing of a silent film, which is to carefully select and remove the footage according to the instructions of the storyboard script according to the order of the combination that best demonstrates the screen effect.

"I see, it's how the movie was edited." Li Kangping's sound film team has a new harvest.

"So, editing the sound requires new editing equipment."

In the days that followed, a team of engineers from New York continued to learn about the art of film, and Walt Disney learned about science and technology through these engineers.

Mr. Lee's sound film team returned to New York in early February, and what they wanted to do was turn their imaginary recording equipment into reality.

Zeus Labs rented a factory in Brooklyn as a temporary workshop for the development of sound film equipment. Li Kangping was hands-on, and he worked with the technical team to discuss the engineering design of the sound film equipment.

"The first thing to do is to engineer the pickup device, how should we design the microphone?" Li Kangping said and wrote in front of the blackboard, "The inside of the condenser microphone is mainly composed of two parts: the capacitor capsule and the preamplifier, when the sound wave signal emitted by the sound source acts on the diaphragm of the capacitor capsule, the diaphragm displaces, so that the original capacitance in the capacitor capsule changes. After the weak capacitance is amplified by the preamplifier, the output current changes in proportion to the size of the sound wave of the sound source, so theoretically speaking, the signal voltage of the sound is generated, and the conversion process from sound energy to electrical energy is completed. ”

"According to Dr. Li's engineering concept, a condenser microphone needs a certain operating voltage to maintain its normal operation because it is equipped with a condenser capsule and a preamplifier inside?" Jack asked.

"That's right." Li Kangping drew his intention on the blackboard, "This voltage should be divided into two groups, one is the power supply to the preamplifier, and the other is the polarized power supply to the microphone condenser capsule diaphragm. ”

"Dr. Lee, I have a question." A red-haired engineer said.

"Andrew, please."

The team is now in the substantive engineering design phase, and the questions asked by the engineers are all substantive engineering and technical questions.

Li Kangping had in-depth exchanges with the engineers and determined the engineering design framework of the condenser microphone.

With the framework in place, the next step should be to determine specific technical indicators.

There are two main ways to set technical indicators.

The first is the analysis of the benchmark product.

The competitor of the R&D team of Zeus Laboratories sound film equipment is the Xidian company.

The team of Dr. Lee de Forrest of Xidian has developed a sound film device.

We brought in the sound film equipment from Dr. Lee de Forrest's team, tested and disassembled them one by one, and obtained the technical parameters of their equipment, which were used as reference data for the technical parameters of our recording equipment.

However, Dr. Lee de Forrest's team was so strict with secrecy that Li Kangping's team was unable to obtain their equipment.

Therefore, Li Kangping's team adopted the second method--- experimental exploration method.

The experimental exploration method of violent trial and error is too time-consuming, and Li Kangping gave the approximate range of technical indicators after derivation and calculation: "Sensitivity is an important technical indicator of the microphone, and I calculated that the sensitivity of the condenser microphone should be between 2~20mV/μp......"

“…… These are the main specifications of a condenser microphone that I have calculated. Gentlemen, in fact, a lot of the work we are doing now is innovative in nature, and I believe that some of the new equipment and new technologies we have conceived, the team of Xidian Company has certainly not heard of it. Therefore, we don't have to worry too much about how Xidian does it, we just design our recording equipment according to this version of the technical specifications. ”

Li Kangping drew a schematic diagram of the project, and the detailed engineering design drawings were completed by 10 engineers.

After the engineering drawings are completed, the production of the pickup device begins. After the equipment is made, it needs to be tested, and it is OK when the test is qualified. This is only the engineering design of the pickup equipment, counting the engineering design, production and testing of other recording equipment, the overall engineering volume of the Zeus Laboratory sound film equipment research and development project is very large, and it is far from enough to rely on 11 people, and new technical personnel need to be added in the future.