Are You Missing Out on Everyday Sounds?

Decibels (dB) refer to how loud or soft a sound is, or its intensity. A person without hearing loss can typically hear sounds from 0 to 85 dB. Someone with mild hearing loss is unable to hear sounds below 30 or 40 decibels, while a person with moderate hearing loss will miss sounds below 50-70 decibels. Since a lot of speech occurs within 55-65 dB decibel range, a person with moderate hearing loss may have trouble hearing (and comprehending) conversations, especially amid background noise.

Sound frequency is measured in hertz (Hz) and refers to the tone or pitch of the sound. Low frequency sounds are the bass sounds like a tuba where high frequency sounds are the treble sounds like a bird or cricket chirping.

Generally speaking, the lower the number, the lower the pitch of that sound. Most everyday sounds we hear fall within 250 to 6,000 Hz, though the full range of sounds a person without hearing loss can detect ranges from 20 to 20,000 Hz.

Common low frequency sounds, 500 Hz and lower, include:

• Dogs barking 
• Lawn mowers 
• The sound of thunder 
• In speech, consonants like “j,” “u,” and “z” 

Common high frequency, above 2000 Hz, sounds include:

• Birds chirping 
• A child’s squeal 
• Women's voices 
• In speech, consonants like “f,” “s” and “th”

Typically, high frequency sounds are the first to get missed when someone has hearing loss. Why? The hair (or nerve) cells in our inner ear that perceive higher pitched sounds are more likely to get damaged first, based on the anatomy of our inner ear. These nerve cells can be damaged by a number of different causes, but exposure to loud sounds is one of the most common reasons.

Someone with high frequency hearing loss has trouble hearing sounds in the 2,000 to 8,000 Hz range. They often find it difficult to understand women and children when they speak, due to the higher pitch sound of those voices. Certain high-pitched consonants like “f,” “s” and “th” (4,000-5,000 Hz) also might get missed, causing speech to sound muffled or garbled. People with high frequency hearing loss will frequently say "I can hear, but I don't understand."

In contrast, low frequency hearing loss means it is more difficult to hear or understand low frequency sounds below 500 Hz, such as the hum of a refrigerator or roar of a garbage truck. This type of hearing loss is often due to genetic factors, a congenital defect, or a malformation in the middle ear -- missing or damaged ear drum, injury to the middle ear bones, or otosclerosis.  Also, chronic ear infections can cause low frequency hearing loss.