Yeah, 3 hours of straight concentration doesn't seem like ADHD.
Actually, with ADHD the brain is extremely locked to the interesting task it's doing and it is possible to work countless of hours without even remembering to eat or drink. The problem of concentration happens if you don't have something that is
interesting enough to concentrate on. When you do, you can't think anything else and the house could be on fire without you noticing it.
On Fisch's problem, I'd love to bet that it's more about the process he's doing that is not giving his overtuned brain enough stimulation. And if you don't
have to do that not-that-interesting task (no urgent deadline, etc), it becomes the nightmare for a brain with ADHD. Enter procrastination, or "research and development" as I try to convince myself. Just how many times can you actually re-order your sample libraries? It can take me two weeks to come up with
one idea for a project I'm not interested in while I can compose, arrange, mix and master a full song from scratch when I'm in my own zone where only I and the project exist in the world. I bet that when you can enter to that zone, you could so the thing you're doing for hours in a row,
@ein fisch ?
For what it comes to concentrating on even that three hours, I don't see that as a problem in case you just get results. So called "normal" people may spend the whole day on things which a brain loaded on ADHD can do in a couple of hours. Don't think about the time, think only about the results. But if you feel like you should be able to do more, you can try the
Pomodoro- technique which may or may not help. The last time I tried to something similar, called
Timeboxing (so many fancy names to all these things) I just ended up getting stuck on the first project on the schedule, re-scheduling everything else for the next day...and the next day....and the next. But hey, at least the first project was a success when I finally got that tackled down. :D
My best advice is that as the mental stimulation plays a huge part on the outcome of concentration, try to pick the project you're working on based on your current feeling. If you feel like doing that "other thing" right now, do it. Otherwise you may as well spend the same time on
not doing that other thing you were supposed to do because of procrastination and unable to concentrate on anything. You concentration is directly dependant on the stimulation of the task and no single internet-site-blocker app isn't going to help- you'll either disable the blocker or figure out another way to weasel out from the task that isn't stimulating enough.
ADHD is tricky business. I wouldn't change my brain into anything else, because that is a huge part what has made me to succeed in many parts of my musical career. The downside is that it's impossible me to relax most of the time and I always need to have different projects going on (outside of my regular work, which is ironically also composing and music production) or I get bored and cranky. And when I have those projects, it's hard to not to be devoured by them, and thinking of nothing else before they are finished. Lucky for me, my wife knows exactly when she needs to understand my "features" and when to tell me to get a grip on things- especially for what it comes to home and the kids. Not many people are as lucky as I am in that sense.
The best help for me is definitely scheduling, TASK LISTS, visual notes and as tidy (spartan clean) and non-noisy working environment I can possibly make it to be. Chaos outside equals chaos inside for me. You could also try that!