Table of Contents
Project SummaryThe Hybrid Audio Processor is device that allows audio professionals to control the amplitude profile of various source audio signals, most notably audio sources used in Motion Picture Pre-Show. An amplitude profile influences the way humans perceive sound. We often use words like ‘punchy’, ‘loud’, or ‘full’ when describing the amplitude profile. Being able to control the amplitude profile is very useful. It allows for the user to create interesting, dynamic sounds that please listeners, as well as provide protection for down stream devices.
Current dynamics processors on the market are high cost and lack some flexibility. This device would allow for advanced control while maintaining ultimate high audio fidelity. It would also be intuitive with familiar, industry standard controls. The device would also have user savable settings as well as try to achieve a lower cost than comparable units. Current professional units have a variety of design trade-offs that do not provide the optimal user experience that is described above.
The goal of this project is identify the needs of Motion Picture Pre-Show industry and develop a product that fit’s their needs, while maintaining the familiar attributes of common dynamics processors.
Customer Requirements (Needs)
|CR1||9||Auto mode, user defines desired output, system keeps output consistent|
|CR2||9||Manual mode, user can modify compression through user interface|
|CR3||9||User interface based off of current state devices|
|CR4||9||Signal output quality: low noise, low distortion, no clipping|
|CR5||9||Audio output quality: Comfortable range and volume|
|CR6||9||2 audio channels, stereo capability|
|CR7||9||Ability to switch output between the device output and device input|
|CR8||3||Ability to switch between stereo/mono|
|CR9||3||Ability to monitor gain-reduction in real time|
|CR10||3||Ability to save/load settings|
|CR11||1||"look ahead" ability|
• What work does your company perform?
Company collects ads to be shown at movie theaters. Company prepares ads so that they show and sound nicely in the theaters.
• What specifically do you want this processor to do?
Wants a way to normalize sound easily from multiple different advertisements. Needs to eliminate “noise”.
• What about controls and a display?
The current box has too many controls (5+). Wants to have only a few controls. Also wants a way to save configurations. • How many channels on the input line?
Two channels to allow for stereo inputs.
• Additional notes:
Most problems with audio come from small companies. Large companies like Coca-Cola spend an enormous amount of money perfecting their advertisements. However, small mom-and-pop shops do not have the resources to perfect the sound in an advertisement.
Wants to decrease response time. Meaning that once an audio level suddenly changes, the volume should be changed to a more reasonable level fairly quickly. However, this change should not be so quick as to sound unnatural.
Follow-up Customer Interview:
- He looked through the customer and engineering requirements.
- Currently, each advertisement needs to be tweaked and tuned, a manual process.
- He does not trust fully automatic systems.
- He still wants knobs.
- He wants an auto feature where the knobs are automatically set.
- He is ok with going back to manually change some features of some of the advertisements after listening to the modified advertisement.
- He wants to easily be able to compare the audio before and the audio after the filtering.
- Most engineering requirements should be set from current audio standards.
- There is no requirement for audio quality and automation capabilities.
- Common issues from audio processors is well-documented online.
- Audio quality should be heard comfortably, meaning that there is no distortion and no clipping.
- Some advertisement’s audio consists of a cheap MP3 file, which causes information to be lost as a result of the poor quality.
- A problem is that some advertisements have overly dramatic audio effects that do not sound good in theaters.
- There are three different types of audio to consider: voice, music, and sound effects.
- A good advertisement may have a video with a voiceover which eventually fades to music.
- Audio dynamics play an integral role in an advertisement. Typically, thresholds and attack time are altered when adjusting audio.
- Need to research audio quality, audio quality ranges, sampling data rates, hysteriss.
Engineering Requirements (Specifications)System-level and function-level requirements that define the intended performance of your system.
Project Goals and Key Deliverables
- A working prototype
- All design files (ex/ source code and libraries)
- Documentation with board schematics and board artwork
- Test results verifying proper functionality