He has a video on the Bass frequencies as well if you need inspiration for low end concepts. Starts at 4:10.

Hey Mansur!

I'm on level 23 of Bass Detective. For the bass frequencies, for me it helps to hum the notes as I know I mentioned before in your other posts. If you don't have a low singing range it's harder, but it may help nonetheless - maybe at least with 200hz? I spent a good amount of time to really figure out my range again with a piano, and then figured out the exact frequencies of each note. So as an example, I can BARELY sing 98hz which is a G2 - my voice starts going into vocal fry currently (once upon a time in Choir I could sing a touch lower lol). 110hz is the lowest nonfry I can currently do. 130hz is like my relaxed speaking tone. 164hz is low but with a bit of energy to it. 220hz is full voice with energy, but comfortable (not pushing yet). 261hz I'm starting to push a bit. 329hz is about where I want to switch to falsetto if I'm lazy and don't want to belt. This helps me when I need to get precise or double check. Each voice will of course be different, so it helps to get familiar with your own voice and the way it feels to sing each fundamental frequency. It doesn't work 100% of the time, but I'd say it helps quite a bit about 60-70% of the time for me,

So you could try to do a similar thing. Humming the notes doesn't always work, esp with drums, but it helps regardless because it gives you a reference point. If the amplified sound feels like it's kinda in a singable vocal range, then you have a sense of where it might be, even if you can't actually hum it. If it sounds like it's way too low to hum, then you probably know it's below the frequencies of your range.

Another tip with Bass Detective is that from about 80hz down it starts sounding boomy subby to me (probably depends on your room). 50hz is epicly subby. If there aren't that many low frequencies in the track, then you'll notice a SUBTLE boost in the lowest frequencies (which may only be 100hz - but it'd be more subtle than if they boosted 100hz directly). This is because the bell curve boosts are fairly wide. So if there isn't any sub info, then the nearest low frequencies will get boosted, but ever so slightly.

100hz is usually a thick kick. It's that low thump. Present. Different from the sub feeling. It has definition, but isn't too boomy like 200hz. Listen for it. Try to practice with it and notice the difference between that and 200hz.

200hz is usually a very thick snare sound. Kinda boomy.

North of 200hz starts getting nasal. So the 250hz you hear that oo sound. Close to 400hz you start getting more of an oh. In 400hz you really hear the low end of the cymbals getting an ooh/oh sound I've noticed.

And then split the difference for in between. Like if it sounds kinda not quite like 200hz, but not as low as 100hz, try 150 and see if that does it.

Also really take your time and listen. Sometimes I notice a boost at 200hz for instance actually makes the 100hz kick sound a lot thicker and I think the 100hz is being boosted. But if you go back and forth a bit, you can start to really notice that the low frequency stays, and it's the slightly boomier higher one that goes in and out - it just adds a lot of the presence of the particular kick in this instance.

If none of this helps, just practice as often as you can, and just try to go about it intuitively. You'll start to get a sense of how low or high something feels.

I think breaking it down into just a few sections at first helps. I started with just paying attention to 50hz, 100hz, 200hz and 400hz. That gets you your Sub, Typical Kick, Typical Thick Snare, and Low Nasal tone at 400hz. Then start noticing and working on the in betweens. I think trying to figure out too much at once can be harder. Slowly increasing your hearing resolution is probably easier for the brain to learn that way.

You could also try the practice rounds (and make sure to switch the sounds at the top to try other options), and just try to describe the sounds for yourself as you hear those different boost sections - 50hz, 100hz, 200hz, (300hz if you want) and 400hz to start. Listen for those repeatedly and see how you'd describe them for yourself. I think you'll likely have better results if you think of your own descriptive words for those frequencies and how they affect the sound rather than reading my descriptions or someone else's or a chart online! Haha (: doing that will also probably help solidify the info as well and signal to the brain that it's important.

And also, goes without saying, make sure whatever you're listening with can playback bass frequencies fairly well. If your monitors for instance die off at 80hz, then you won't be able to tell whenever there are subs.

Hope this helps!! Cheers (:

thank you for you reply!