Hi Melo,
I agree, we need more context. Posting up a picture of the back of the product in the shop and saying “what do you think” will generate random feedback. ID is not just about creating a random housing for a speaker. Without any context; materials and shapes are just random.
It looks like your goal was to build a box around the speaker rather than design a product. Pay more attention to your detailing, placement and selection of cords and power buttons. Why is the cord so far to the left? The power button seems like you got it from Radio Shack.
I know you’re exited about building something that works. However, prototyping is towards the end of the design process. You should post more about your process so that you can get more constructive criticism.