First, let’s cover the situation where you use the composite cable plugged into your laptop first. This is my primary connection used with my TV Adapter 3.0. In this scenario, the first stage of volume control is from your laptop. You’ll find that you’ll need to set your laptop to a certain minimum volume level (as displayed on your laptop) before it will trigger the TV Adapter from being in standby mode (red LED) into the operation mode (2 green LEDs). You can reduce the volume on your laptop and still be able to hear it on your OPN, but if you reduce it too much, after about 5 minutes, the TV Adapter will go into standby mode (red LED) because it doesn’t detect enough volume that surpasses its minimum volume threshold level going into the TV Adapter from the laptop. In this case, you’ll have to raise the volume on your laptop to a certain point, and you’ll notice that the TV Adapter shows 2 green LEDs again, and you’ll hear the sound streaming to your OPN again.
But let’s say at this minimum volume threshold level set on your laptop to keep the TV Adapter from going into standby (red LED), it’s too loud for you and you want to adjust down. You can do it a couple of ways. Either use the ON app (if you have an Android phone) or the volume button on your OPN to turn down both the streaming volume.
The side effect of this is that the environment mic volume will be turned down as well. This may or may not be desirable. If you don’t want this side effect (you want the default environment mic volume), you can turn down the laptop volume instead to a more comfortable level. However, the side effect of THIS is that after a few minutes, the TV Adapter will go into standby mode, and you’ll need to “wake it up” by increasing the laptop volume until there are 2 green LEDs and streaming resumes, then turn down the laptop volume again into a comfortable level again, and repeating this cycle, which is a nuisance.
If you want to raise the streaming volume instead, I’d suggest you raise the volume of the laptop going into the TV Adapter, instead of using the ON app or the OPN volume button to raise the volume. The advantage of this is that you will be able to avoid raising the environment mic volume up in conjunction with the streaming volume. As long as the laptop volume is not too loud to cause distortion (and it shouldn’t be), then it’s all good.
The ONLY way to INDEPENDENTLY control the streaming volume and the mic volume separately is if you have an iPhone, and you use the iPhone’s MFI volume control menu. In this case, the iPhone MFI volume control gives you 2 separate controls, a Mic volume slider, and a TV Box 1 Volume slider. If you leave the Mic volume slider at the default level, the TV Box volume slider will vary the streaming volume independently and the mic volume remains at the default level (which is 64% in my case, yours may be different). If you hand mute the Mic volume by the OPN volume button (via a long hold on the button until the mic is turned off), the TV Box 1 volume slider will also operate independently while the mic volume is being mute. BUT, ONLY IF you HAND MUTE the mic volume via the OPN button.
This is where it gets confusing. IF you adjust the mic volume SLIDER, it NOT ONLY affects the mic volume, it’ll ALSO affect the TV BOX 1 streaming volume in parallel. For example, my default mic volume is at 64%, This is also where the default volume streaming volume is at. In another word, the Mic volume represents both the volume of the mic and the volume of the streaming. The TV Box 1 volume slider is only 0-100% of this default streaming volume.
So for example, if I reduce the mic volume down to 30% (from the scale of 0-100%), that means that my mic is at 30% volume (where default is 64%), and my streaming volume is also reduced to 30% of its max streaming volume (where the default streaming volume is 64%). By now, the TV Box 1 volume slider operates between 0-100% OF THE 30% streaming volume. It’s like a slider within a slider…
In a way, this Mic volume slider is equivalent to the combined volume control either on the ON app, or on the OPN button, where both the streaming volume and the mic volume go together in CONCERT.
So in a way, the TV Box 1 volume slider is not really totally 100% independent from the Mic volume slider. It is a 0-100% scale adjustment of whatever the streaming volume is, as set by the Mic volume slider, which controls both the streaming volume and the mic volume together.
Before I go on, I need to say that MUTING the mic by long pressing the OPN volume button IS NOT THE SAME as sliding the Mic volume to 0%. That is because the earlier (long pressing the OPN volume button) PRESERVES the current value of the streaming volume and only mutes the volume of the mic. As opposed to when you slide the mic volume slider to 0%, what you inadvertently do is to not just reduce the mic volume to 0%, you’re also reducing the streamer volume (not to 0%, but to a very low streaming volume level, another quirk, I guess).
Now, having said what I just said in the above paragraph, the most volume you can get downstream for streaming (assuming that the input level to the TV Adapter is at a fixed volume) is by increasing the Mic volume slider to 100% (to get the streaming volume to 100%), then manually mute the mic by the long press on the OPN volume button, THEN control the streaming volume with the TV Box 1 slider.
If you don’t have an iPhone, then you’re really limited to using the ON app to control the streaming volume, in conjunction with the mic volume, and they’re not separable. If you have an iPhone, you can have better control of both as described above.
In the end, if you’re using the composite cable connection from your laptop (or whatever) and you don’t have an iPhone, the best bet to control the streaming volume and leaving the mic volume at the default level (or even when muting the mic by a long press on the OPN volume button), is to vary the volume from the laptop. The trade off is if you vary the volume from the laptop downward too low, you may risk putting the TV Adapter box into standby after a few minutes if the volume output is below its threshold.
Now I don’t have a setup where I use the optical cable so I can’t talk in details about that situation. But I’d imagine that although you don’t have the situation of risking the TV Adapter go into standby due to being lower than a threshold level, if this optical signal is a fixed volume input into the TV Adapter, then you’ll run into the same issues as explained above about the limitation of using the ON app or the OPN volume button to control the streaming volume, vs using the iPhone MFI volume control with both a Mic and a TV Box 1 volume slider.