Hey,
Do you know and use any mobile apps that help with learning/memorizing theory.
I’ve been using “Guitar Note Trainer” by Justin Guitar and it really helps with memorizing the fret. It has many quiz options.
It is great, as I quite often use it between exercises at the gym.
Now, I’m wondering if there are any apps that can quiz your knowledge of something like scales, circle of fifths or any other useful music theory aspects.
Tenuto tests a lot of that stuff, fretboard note identification, staff note identification, key identification, constructing interval or scale quizzes, etc.
Edit I forgot to mention it’s free, it’s from musictheory.net
Scales for Bass is a good one. Also Music Theory.
I would second Tenuto!
Yeah, looks great. Alas, iPhone only 
I use smartChord, because I don’t memorize anything I can look up 
While I agree in general with that statement, I also think that there are some information worth memorizing. Especially those that are fundamental knowledge and have big impact on your playing.
I can’t imagine looking up everything while playing 
Not an app but I took an in-depth course on theory at Blues Guitar Unleashed and at the end of each lesson there would be a quiz. I found it quite helpful.
Theory is something I do not feel you will ever get to the end of learning.
I have been playing at music for 65 years now and have played drums, cornet, E♭ horn, piano/keyboards, recorder, Irish Whistle, Electric and acoustic guitar, bass, harmonica and banjo. While I learned to play these and played quite well in bands with them there was, and still is, no end to learning music theory for me.
The theory Josh teaches in the course is more than you need to know to be able to play the bass.
Just don’t let yourself get overwhelmed with theory. Play and enjoy yourself.
When you have an engineering background you usually try to understand how things work (at least to a certain extent) 
But I agree, as a non-professional player you should probably draw a line somewhere and enjoy.
I agree but my problem is I enjoy theory so the thought of drawing the line has never crossed my mind. 
As an exercise, draw your own circle of 5ths/4ths showing all Major and Minor keys and then construct their associated scales.
You might consider how one progresses on their way to an engineering background… because nobody is doing any of that engineering stuff in school when they’re in grade 1 or 2.
When you’re learning music or languages it’s often good to just accept that things are the way they are and you can come back and understand why later. You learn to speak long before you learn what grammar is. Ask a native English speaker what the rule for the order of adjectives is and they probably won’t be able to tell you.
One reason that children are good learners is they just use/repeat things until they learn them, without worrying why. Another is that they conduct their own experiments to understand how things work. One can understand how things work without knowing why.
That circle of 4ths/5ths is incorrect, there should only be 12 spaces on it for the 15 keys. The circle is great for a lot of things and giving it 15 spaces breaks that.
The 4ths are: C, F, Bb, Eb, Ab, Db, Gb, B, E, A, D, G
There are only 12 Major keys, the other 3 keys are enharmonic. You can keep going to theoretical keys too but they’re not very useful 
Anyone who uses more than 5 sharps/flats is a monster… probably the sax screwing it up for everyone 
Can verify. This is not taught in school, or at least I was never taught it. I just “know” from absorbing it.
And it’s quite hard to apply a rules-based approach to in practice.
I always enjoy how “quite” has two different meaning dependings on UK vs US English 
“They’re quite good” either means they’re fair or they’re very good 
almost as good as the word “unlockable”. English is silly 
I have a friend that told me the culture shock from moving from the US to London was worse than to Tokyo, because while you expect Tokyo to be a very foreign place, with London it sneaks up on you because you think you understand things, until you realize you really really don’t
I don’t think so.
Ever seen this video:
YES!!! Winner Winner Chicken Dinner.
Say goodnight Gracie.
I’ve seen it and he said exactly what I said; there are 15 (major) keys… but he wasn’t talking about the circle of 4ths/5ths and there are only 12 spaces on that which proceed in 4ths CCW and 5ths CW.
If you proceed around the circle in 4ths (5 ST) you get C, F, Bb, Eb, Ab, Db, Gb. What comes a 4th after Gb? Gb, G, G#, A, A#, B: B is a 4th after Gb; your chart shows Cb which is fine, that’s the enharmonic of B… so we continue, Cb, C, C#, D, D#, E. The next 4th is E, but your chart show C#. The following 4th is A but your chart has F# and then we get back to B again. That totally breaks the utility of the circle.
Db/C# are the same, Gb/F# are the same, Cb/B are the same; they’re 3 spaces not 6, they don’t all get their own spaces on the circle. And that’s as far as we go (without theoretical keys) since we only have 7 flats and 7 sharps.
And their 15 relative minor keys. So my chart shows a total of 30 segments for that very reason.
If you do a google search for how many keys there are in western music you get all sorts of different answers. Some getting into enharhonics, like you did. No wonder a lot of people get confused by music theory.
The whole purpose of the blank chart was to give @jacq something that he may be able to use to construct all of the Major and Minor keys and their scales, regardless of enharmonic keys. Just trying to help out. No more no less.