There are 2 reasons why a pressing Push Button may not alter the sound quality: (1) The button has not been programmed to control anything or (2) If it has been programmed to control volume or a specific environment, it may need an adjustment to work better for you. Let me elaborate.
During a hearing aid fitting with a new user, I typically don't program the button to control anything. This is in part because I want the new user to adapt to putting a hearing aid in, opening the battery door at night, and changing the battery. But it's also because I want the new user to adapt to listening with their new hearing system, analyzing what is working well and what they wish would sound better, different, etc. At the office we validate that our guest is hearing "as they should," but each person is unique in what they like and don't like in their soundscape. At the second appointment, we work on finessing the sound quality based off of the guest's experience. Part of that may include activating a push button as a volume control or a different mode for a specific environment like a restaurant. Typically you will know if your button isn't activated if you press it and hear no beep or click. But if your hearing device has a button and you would like it change volume or "mode," call your provider to discuss it with them.
If the button does make a beep or a click indicating that it is changing but you aren't noticing any difference in the sound quality, you should also call your provider. For instance, there are many different ways that a noise or restaurant mode can be designed. Your provider most likely started with a best practice that works for a majority of his/her clients, but for you there is something about it that makes it ineffective. Come back with an explanation of why it isn't working like: "It doesn't sound different," or "the noise in the environment is less loud, but I still can't hear the speaker," etc. Your feedback helps us optimize your device so that it fits YOU! We want you to love your hearing, so if there is anything that is not working the way you would like let us know!
It all depends on how the hearing aid was set up in the software. It can be used for volume change, program change, another proprietary feature, or have no function at all. A quick call to the audiologist who set it up can easily open your file and give you the answer to how your aid is set up. If you dislike it, or want it set differently, they should be able to see you for a very quick appointment.
It could be several reasons.
1. The button is malfunctioning
2. Depending on how the button is set in the fitting software, it could be set for Volume, or Programs. Programs are presets, they respond to sounds and sets of sounds in different ways. For example, in a restaurant program, you may have more directionality, more noise reduction, or fixed directionality. You may not notice a difference between your main memory and restaurant memory in quiet, since it is designed for noise, if there is none present then it will sound about the same. You can also set a button for both programs and volume. Typically this is done with one side short press making it louder, and the opposite side short press softer, long press (about 2-3 seconds) would most likely be programs. You will have indicators for each program, either beeps or voice.
3. The button is unprogrammed, or disabled in the fitting software.
You need to see the person who programmed your hearing aid. Ask for a printout of how the buttons and VC (if you have two controls on the aid) so you will need to find out how the hearing aid is set.