I am looking for someone to design the electronic circuit for a customized speaker.
Please see the specifications that I require. Please give me a quotation based on the following. We are able to compensate attractively.
1. Performance requirements: The device must play 18000 - 22000hz. Audio Amplifier: Minimum 8Watt - 15Watt. The device must run on AC power and starts playing once the power is turned on ( meaning there is no on/off switch ) and loops; meaning it will keep playing forever until the power gets switched off. The device will play the MP3 tracks from a SD card that is embedded inside the box. This SD card must not be visible from the exterior and not be able to remove easily. (If someone wishes to change the SD card, they will have to unscrew the exterior cover to do so).
2. Speakers: I have attached the speaker we used currently for our prototype( which we built to test the usage but we will need professional circuit design). However you have full flexibility to use a speaker (and other parts) of your choice to minimize costs. Minimum, it must be able to play 18khz to 22khz without any performance issues. If the speaker can play higher than 22khz, that will be much preferred. (pls advise if possible)
3. Box Size: should be approximately around 180mm (length) x 80mm (breadth) x 70mm (Height). So the circuit must roughly fit inside these constraints. If there are issues with size, we can discuss further as the shape/size of product is flexible.
4. Power: for the whole box: 9V 1 Ampere
5. Box design: I have attached a sample exterior cover design below. It will need to have ledges on the side to allow for screws and easy wall mounting.
The box must not be easily identifiable as a sound emitting device. It will be mounted in public on walls so a neutral colour like white / grey will be good and should blend into the environment.
6. Volume: Must be as loud as possible and and starts playing once the AC power is turned on ( the loudest volume ). When we play the sound freq above 20khz, it must not be audible to the ears at all.
7. Environment: This box will be used in places where there is background noises. As such, the volume of the sound frequency played by our box must be loud enough to overcome this.
6 freelancers are bidding on average $1200 for this job
I have the similar products as what you descripted, but the box sizes are a bit bigger(185X130X95 and 180x180x130mm) than you you expected then the box can be mounted with two speakers to provide more powerful noise.