Dell laptop Inspiron 3542 speaker is too low

Dear,

I have a new 3542 laptop but it's speaker is very low. I try earphone with 10% volume, the sound very clear, equal speaker with 100%.

My laptop is running windows 7 home premium 64.

I also install the latest driver at http://www.dell.com/support/home/us/en/19/product-support/product/inspiron-15-3542-laptop/drivers/advanced but did not pass this issue,

My previous dell laptop N5040 with the same windows version does not have problem.

Thanks,