First of all, to tell you, this is definitely caused by the limitations of hearing aids. Because from what you say is good for one-on-one mode communication in a normal room, you can see that your speech recognition rate is still good.
For every meter increase in the distance after the sound is emitted from the sound source, the overall sound intensity of the sound source will be reduced by 6 decibels, such as a person's speech sound is 70dBSPL when it is at the mouth, and the sound intensity after more than 3 meters becomes 52dBSPL, and the noise intensity of the general quiet office environment will be 45-50dBSPL(A), at this time, if you are more than 3 meters away from the sound source, there is almost no difference between the speech sound you want to listen to and the noise floor noise intensity.
That is to say, the language signal you want to listen to can no longer jump out of the ambient noise floor (academically known as the signal-to-noise ratio), the language language and the noise floor are mixed together, and it is more difficult to screen out the speech for people with hearing loss.
A person with normal hearing, when the signal-to-noise ratio is relatively weak, the brain's analytical processing ability will play a role, and will mobilize the binaural listening function to locate the sound source that you want to hear (speech sound, in addition, because the speech frequency and intensity change is relatively fast, the brain can use speech information and noise background noise frequency changes to distinguish speech and noise), and the brain can also filter out a part of the background noise at this time (this is also a theoretical theoretical basis for the generation mechanism of tinnitus), this ability is easy to achieve for people with normal hearing. But once a person has hearing loss, this ability to selectively listen becomes weaker and weaker with hearing loss.
There are two main ways to solve this phenomenon, one is to increase the amplification ability of the hearing aid, especially for the amplification intensity of small sounds, even if it is more than 3 meters away, the speaker's speech sound is still very loud when it reaches the ear worn by the hearing aid, which will make the audible distance long. But in this way, the ambient noise floor is also amplified, because the sound of the environmental noise floor is continuous.
Hearing aid users can also accept these noises for a short time, but a little longer may feel that the noise can not stand, to solve the problem of noise, you can raise the noise reduction level of the hearing aid to the strongest (any hearing aid noise reduction ability is there, the strongest and most ideal hearing aid can reduce the ability to stabilize the noise floor at most 6-8 decibels).
Another method is to start the directionality of the hearing aid, the function of the hearing aid can be directly in front (some hearing aids can intelligently identify the ability of language direction, although many manufacturers are set to pass some exaggeration, but indeed some hearing aids have a little bit of this ability) sound amplification, when you face this speech, the speech sound intensity will not be reduced, and the background noise will be reduced, this time increase the volume of the hearing aid to make the speech intensity greater, this method will be better than the effect of starting the hearing aid noise reduction function, Of course, this method will also slightly reduce the intensity of speech sounds, although the sound of speech is directly in front of you, but the sound intensity of speech sounds returned by obstacles is also reduced.
Another way is to use wireless devices, if you are too far away from the speaker, you can use a device called Bluetooth microphone (some manufacturers recommend choosing FM device, FM wireless propagation distance is about 4 times farther than the Bluetooth microphone, but its cost is about 7-8 times the Bluetooth microphone), the current 6 brands have this wireless device, you can put a small box called Bluetooth microphone on the speaker's body, podium and other places close to the speaker.
It's like pulling the speaker's voice closer from 10 meters to 1 meter (equivalent to the distance from the blue microphone to the speaker). This way your listening is much easier. Of course, this wireless function is only suitable for hearing aids with wireless functions, generally more than 5,000 yuan of back-of-ear and large ear canal hearing aids have this function.
The above first method is usually only suitable for the application of specific sounds to listen to a little farther away, because in the general environment to adjust the noise caused by the small sound intensity of the hearing aid is difficult for most people to adapt, then the fitter needs to set up two programs for the user, one is specifically for listening to the program used to speak a little farther, one is the program used in the normal environment, so that the user's self-adjustment, in order to obtain a better listening effect.