Bands vs Channels (Best OTC hearing aids)
Duan Jirong Hearing Health Guidance
Frequency band is the most easily confused concept with channel. The figure below shows the relationship between frequency bands and channels. The frequency band is a section of frequency on the acoustic signal spectrum, which is set during the circuit design of the rechargeable hearing aids. For example, the 8 frequency bands in the figure are fixed once divided. Open classification. The more frequency bands, the finer the division, but it does not guarantee independent signal processing.
Channels are regularly combined on the basis of frequency bands. Changing the channel dividing line on the fitting software is actually changing the range of frequency bands contained in each channel. In the channel, special signal processing such as gain, compression, multi-channel microphone processing, and noise suppression can be adjusted independently of other channels, and the signal gain in each frequency band is not adjustable on the fitting software. Therefore, for clinical fitting For teachers, what is really meaningful is the channel.
Hearing aids that can independently adjust gain and compression in different frequency ranges are called multi-channel hearing aids, which distribute input signals to corresponding frequency regions according to different frequencies, and the split signals pass through corresponding amplification channels, as shown in the figure below . The biggest advantage of multi-channel hearing aids is that it can improve the flexibility of clinical fitting. Independent gain adjustment can meet the needs of non-flat hearing-impaired people for different gains at each frequency, which means that different hearing losses only need one hearing aid circuit. OK.
In a multi-channel hearing aid system, each channel has an independent compressor. The reasons for assembling independent compressors for different frequency channels are as follows:
First, hearing loss is usually not the same at different frequencies;
Second, the main energies of ambient noise and signals are at different frequencies. People live in a complex and changeable sound environment, including loud and soft sounds, as well as high-frequency sounds and low-frequency sounds. The hearing-impaired people have different perceptions and needs for sounds of various natures. Therefore, hearing aids are required to not only handle small sounds and normal conversations separately It should also be able to amplify or suppress different frequencies of small voices, normal dialogue voices and loud voices. Multi-channel hearing aids can accomplish this goal, and can adapt to the needs of different gains and compressions, so they have high flexibility.