I can try to answer for the OPN only as an owner wearing the OPN, and somebody else can help answer for the LINX 3D who wears it.
While the OPN can hold up to 4 programs, it does not have an automatic adaptive system that automatically detects the listening environment and changes from one program to another depending on the listening environment. It always stays in one program only until you manually switch to another program.
HOWEVER, this is not to say that the OPN doesn’t have the capability to detect a listening environment. But the way the OPN defines a listening environment is different than other HA brands. For example, the listening environment for a non-OPN brand may be associated with the program, like “quiet” mode, “car” mode, “restaurant mode”, “music mode”, “outdoors mode”, “windy mode”, etc. and the listening environment is detected to activate the switching to the appropriate program/mode.
But for the OPN, the listening environment is not associated with program/mode. It’s simply defined as “simple” listening environment on one end, and “complex” listening environment on the other end. Simple environments here defined as low or medium level, with low reverberation effects, and few disturbing sound sources. Usually, there is a high SNR (signal to noise ratio) making it easy to hear target speech. If there are multiple sound sources, they are spatially separated making them easy to tell apart from each other. An example of a simple listening environment could be a living room where the television is on at a low level and there are two talkers, besides the hearing aid wearer, who are sitting on either side of the person.
Complex listening environments are here defined as environments with a low SNR or a fluctuating SNR, and high sound levels. Multiple sound sources are present and are difficult to separate spatially. Reverberation and wind noise may be present and there may be noise sources that make it difficult to hear and understand target speech. An example of a complex listening environment can be a conversation between four people at an outdoor café on a busy street.
Based on the personalization of the wearer’s preference inputs at the start of the programming, a “help” profile is created for that wearer. It can be Low, Medium or High. This “help” profile in turn sets the control inputs on the Balance module and Noise Removal module to vary depending on the Listening environment. Below is an example of how the control is set for the Noise Removal module based on the Listening Environment across the Help profile:
In each of the 4 OPN programs (there can be up to 4 but usually only the default one is enough), the Help profile and the noise reduction level for Simple and Complex listening environment can be set/adjusted.
For the OPN, the transitions between simple environments and complex environments as explained above are not points on a line, but rather, they are continuous and smooth. The OSN aka OpenSound Navigator (the OPN core processing engine) cannot be described in terms of modes that the system switches between because in effect there are an infinite number of possible configurations of the system. In turn, this means that OSN does not have a mode switch with the potential audible artifacts that mode switches are known to cause.
So by default you don’t control the transition between listening environments in the OPN, and it’s dynamically activated all the times. The OSN cycles through its processing 500 times per second and it’s all automatic. That’s why there’s really no need to have multiple programs for the OPN. One default program is good enough to manage all listening environments because each program encompasses all listening environments inside that single program already, in contrast to the other HA brands where each program is associated with one distinct listening environment that needs to be detected and switched back and forth / to and from.
I primarily just use the one default OPN program for 95% of the time because it can manage all of my listening environments in that one program already. I only use the other OPN programs to control other static settings, like have my default program 1 with Speech Rescue enabled, program 2 WITHOUT Speech Rescue. Program 3 has Speech Rescue with the volume of the frequency-lowered sounds set to maximum. Program 4 is set to the built-in Music mode where all noise reduction is disabled. But bear in mind that ALL listening environments are managed within every single one of those 4 programs already. So I can stay in any one of those 4 programs all day long and it would still serve me just fine as I move in and out of various listening environments that day.