Individuals with low-frequency tinnitus hear a low-pitched hum. Just because you hear a low hum, however, does not necessarily mean you have tinnitus. You may be experiencing a phenomenon commonly known as "The Hum," which most people believe is caused by real environmental noise. Low-frequency tinnitus can be hard to self-diagnose because sufferers don't know if they hear actual noise or phantom, internal humming.
Sound waves are measured as frequencies. The higher the pitch, the faster the frequency, and the lower the tones, the slower or wider the frequencies. Audio or audible frequencies encompass the range of sound humans can hear. The standard hearing range starts at about 20Hz and ends at about 20,000 Hz. People who have low-frequency tinnitus hear a hum, murmur, or droning in the lowest part of this range. The hum tone can be compared to the lowest two octaves on a piano.
What Causes Low-Frequency Tinnitus?
Most people find this type of phantom noise very disturbing. While the cause can't always be determined, known causes include high blood pressure and other cardiovascular problems, Meniere's disease, and in rare cases an aneurysm, or tumor.
One common cardiovascular phenomenon, the venous hum, occurs due to blood flowing to and from the brain. Blood flows to the brain through the internal carotid and vertebral arteries, and then the it drains through internal jugular veins. Blood flow can cause the vein walls to vibrate, resulting in a hum in the upper chest that can be heard by the individual. A venous hum may be annoying, but it is entirely harmless.
What is "The Hum"?
The Hum is what some people are calling the quite common reports of an annoying, low-frequency humming, rumbling, or droning noise that not everyone can hear. People from the United States, United Kingdom, New Zealand and Canada have reported the phenomenon. While overall, the sounds are referred to as “The Hum”, sometimes the name changes to reflect where in the world people are hearing it The "Taos Hum" in New Mexico and the "Windsor Hum" in Ontario are two of the location hums. Different causes that have been attributed include local mechanical sources from industrial plants, highway traffic and air traffic. Although scientists have conducted studies, the actual source or sources remain a mystery.
Do I hear Real Noise?
Scientists conducted a study in the United Kingdom to distinguish between environmental hums and low-frequency tinnitus. Individuals who complained about hearing a low-pitched hum were tested to find out if they heard internally produced noise or actual airborne environmental sound. The acoustic tests included hum-matching, and standard and low-frequency hearing acuity. They asked participants to distinguish between tinnitus and real-airborne-noise. While the results showed ten of the 48 participants definitely had low-frequency tinnitus, most individuals couldn't be classified. A doctor or audiologist can test your hearing and look for underlying causes of tinnitus. Pinpointing a cause can lead to improving the condition and eliminating the possibility that your humming is part of "The Hum."
Are There Treatments for Low-Frequency Tinnitus?
If the cause is known, treating the cause can help alleviate symptoms. Otherwise, standard tinnitus treatments, including lifestyle changes, sound therapy, and cognitive therapy, often provide relief.
Tinnitus Retraining Therapy (TRT)
For low-frequency tinnitus, health care professionals might recommend TRT. A device inserted into the ear generates low-level noise and sounds that match the volume and pitch the patient hears because of tinnitus. The treatment may last between one and two years. In order to start the process, a patient's tinnitus frequency must first be precisely diagnosed. There are online services available to match frequencies.
Whether you have low-frequency tinnitus or are hearing rumbling from urban noise pollution, the persistent noise can be distracting and disarming. Checking for hearing loss and addressing its cause could help. Otherwise, one of the various tinnitus treatments and therapies might help you deal with the humming.