Specifications on Headphones What Do These Mean?

[EdwardGein]

Can someone please explain the following specifications: frequency range, ohms, sound pressure level as it pertains to home headphones & what one should aim for (more Ohms, sound pressure, etc)? Will I see a noticeable improvement with an open headphone with Frequency Range 8-35000 MHZ 40 Ohms & Sound Pressure Level 94 DB from an open one with a frequency range of 10-25,000, 75 Ohms with same sound pressure level (94)?

[Mr Peabody]

I bought a pair of Sony earbuds that said they went down to 10 Hz. I had serious doubts about that but I bought them anyway hoping they would at least have some bass response based on the rating. They wouldn't do 10 Hz if lightning struck them. They didn't even do mid bass, it was a waste of money. Like most electronics the ratings arent' worth much.

I'd assume the SPL would be the same as with speakers and if both had 94dB they would play about the same loudness with the same input power. Some headphones are easier to drive with a certain impedance but I forgot which range was best, sorry.