128 points by egdels 8 days ago
Hi HN,
I built a simple harmonica practice app that shows real-time pitch and bending targets for each hole. It helps blues harp players visualize their technique and improve intonation.
No tracking, no ads, open source (MIT).
The app is available on F-Droid and GitHub. You can find more details here: https://letsbend.de
Feedback welcome!
Thanks for sharing that — I really appreciate your perspective and experience.
I absolutely agree: bending is a deeply organic thing that you need to feel and hear in your body. No app can replace that. The goal of my app is not to teach you how to bend, but to help you understand what you're actually playing — especially for beginners who are unsure whether their bend reached the target pitch.
It’s more like a "mirror" than a teacher: you still have to do the work with your ears, but the app can help confirm (or challenge) what you think you hear. Some folks find that helpful in the early stages.
Also — yes to Gindick and Jason Ricci! Two amazing resources. I hope my app can complement, not replace, that kind of learning journey.
Thanks again for the thoughtful input!
I also learned from that book + tape about 30 years ago. I also have to strongly agree with this. It's quite different from learning stringed instruments. I'm sure it has a lot in common with some brass instruments, but either way, seeing doesn't help. Hearing and feeling is everything. That also makes it easier than most to learn via cassette tape! :)
The app seems neat, but focused on precision in bending. Precision in bends doesn't matter a ton for most styles. It's more about feel. Build and resolve tension. Don't worry too much about hitting things exactly. That advice will eventually fail you if you go into styles that need a more complete scale, but for blues/rock/country, it's much more about intuition than precision. The best way to learn is to play along with a lot of things and build "feel" instead of trying to precisely hit notes. (though you do need to hit a clean note to start bending)
First thought I had - I never thought that one can bend harmonica (I used to play it as a child and found it quite impossible). Since that time I have no usable harmonica in my home. Another thought I had - I'll test it on learning violin vibrato.
And when I tried it - WOW! This software has very good responsiveness and those rectangles show tune in really clear way. It turns playing musical instrument into some sort of game which objective is "just keep in the middle of all squares". I've just used it to exercise violin piece and it's really helpful in showing me when I'm playing out of tune.
Great help! Thanks!
Could you please add 'no-screen-fadeoff' patch on android? It seems that I have to manually wake up phone every few seconds (depends on phone settings). Also manipulating scale to show lower G would be terrific, however I understand this is not intended for violin playing...
Thank you so much for the kind words – I’m really happy to hear you found it helpful, even for violin!
Let’s Bend was originally designed to support harmonica bending practice, but the idea of using the "stay in the square" feedback as a pitch visualizer for other instruments is incredibly exciting. It’s great to see it working in real musical contexts!
Just to address your points:
There’s already a *“Keep screen on”* toggle in the app settings – enabling it should prevent Android from turning off the screen during use.
You can also *change the root key and tuning system* in the settings. While the interface is still harmonica-focused, this makes the app more flexible – including for lower pitches like a violin's low G.
I’m genuinely grateful for your feedback and enthusiasm – and thanks for trying the app in such a creative way!
This is very nice, thank you for creating it. I have a few suggestions, but they will have to wait until later this week. I see an email address on the Imprint page on your website - is that the best way to reach you?
Somewhat related, for any harmonica player who likes to play cross harp for that bluesy sound, and wants to branch out into songs written in a major or natural minor key (e.g. much pop/rock/country), let me suggest the Melody Maker tuning. This gives you a major scale (along with the relative minor) all up and down the harp in the cross harp position.
And you can still bend notes. You just don't have to for the major/minor scale notes.
For example, a High C Melody Maker is perfect for playing Stevie Nicks' vocal in Dreams. The song is in A minor, but the A minor harps from Lee Oskar and Seydel are in a lower register. The High C matches her range.
The song begins with "Now here you go again", and Stevie has a signature vocal bend on the word "go". She starts that word nearly a semitone flat and then slides up to pitch.
On the Melody Maker, that note is on the draw 3, where it is super fun and easy to start with a light bend to mimic her vocal style.
The nice thing is that you don't have to be so precise on your pitch with this bend. You just start low and slide up, like Stevie does.
I used to make my own Melody Makers by retuning a conventional Richter harp. You raise the blow 2 by a full step to get the second note in the major scale, and raise the draw 5 and draw 9 by a half step to get the minor 7ths. So an F Richter harp becomes a High C Melody Maker and is labeled that way when you buy one.
For years, Lee Oskar only sold Melody Makers in five keys, but now they have expanded it to nine keys including the High C and the Bb that I use for the late Songbird's vocal on You Make Loving Fun.
Seydel has always sold their Melodic Maker (same as Melody Maker) in all 13 keys, but their cover design is so different from Lee Oskar and Hohner that I never could switch back and forth without off-by-one-note errors.
(Yes, 13 keys, because there is both a Low C and a High C.)
Oh - how do you retune a harmonica? File the reeds! File off some weight at the tip and it raises the pitch. Scratch off some weight at the attached end and it lowers the pitch. You just need a single edge razor blade to lift the reed out of its slot, a fine point file or other small file, and an instrument tuner like Let's Bend.
Thanks so much for this detailed and generous comment — it’s incredibly encouraging to hear from someone with your level of experience.
Yes, the email listed on the Imprint page is the best way to reach me — I’d love to hear your suggestions when you get a chance.
And it’s great that you brought up Melody Maker tuning! Even though I don’t currently own a harp in that tuning, I’ve implemented theoretical support for Melody Maker (as well as other Richter variants) in the app already. So users can visualize bends and pitches correctly even when playing in those alternate tunings.
Your Stevie Nicks example is such a beautiful use case. Expressive bending like that — starting just below the pitch and sliding up — is exactly the kind of thing I hope the app can help people hear and understand more consciously.
Also, I really appreciate that you mentioned manual retuning. Let’s Bend was designed to be lightweight and offline, so it’s ideal for checking pitch quickly when tuning by ear or file. That’s one of the practical scenarios I had in mind from the start.
Thanks again — I’m learning a lot from your comment.
Very interesting! I've played harp casually all my life without ever really learning about alternate tunings. The Melody Maker sounds like it would open some nifty possibilities! Someone bought me a chromatic harp once as a gift and I could never figure out how to play it properly. It's funny though, because as a piano and guitar player I never thought about what I was doing. I just play a cheap blues band or marine band, and I realize now that the positions that feel most normal to me are 1st, 2nd and oddly, 12th. I remember once jamming with an old folk rocker (my former guitar teacher) and he started playing something in F major while I was on a C harp. He didn't think I'd be able to follow - at the time, I just called this "cross harp" because I thought that was the generic term for playing in any other key! I don't know why playing in a major 4th seems so unusual, but he was kinda shocked that I pulled it off. There's only one note you can't play straight in that setup...
That is so cool that you discovered those alternate positions!
Yes, "cross harp" is also known as second position. I have never explored the other positions as you have. There is so much to experiment with.
If you ever want to try the Melody Maker tuning, I would pick a song you want to play and get one in that key. I mentioned Dreams (A minor / High F Melody Maker) and You Make Loving Fun (Bb Melody Maker) for the female vocal parts.
Another one I have fun with is Wagon Wheel (the Darius Rucker version). It's in A Major, and yes, Lee Oskar does have an off the shelf Melody Maker in that key.
I do the fiddle part, which was quite a challenge to learn! And the organ part, which is much easier.
I can read music, slowly, but mostly I learn by ear. I used a site called Karaoke Version:
https://www.karaoke-version.com/
This site lets you create your own mix of instruments and vocals for any song.
First I made a mix with everything included, so I could play along with the fiddle and organ parts.
Once I had it down, I made a second mix with fiddle and organ dropped out so I could play those parts on my own. It still included the vocals.
Unfortunately, Karaoke Version later replaced the track with a much inferior version. I have no idea why! If anyone wants the two mixes I worked with (the one including fiddle and organ, and the one without), ping me and I can send them to you on the sly.
I've found Jason Ricci to be a most useful source as well. Adam Gussow, Tom Leckie, Will Wilde, and Howard Levy all have recommended YouTube content.
I haven't checked out the app, but certainly plan to in order to fine tune my scales (major/minor penatonic, blues, and a few more).
By the way, once you get 2nd position major pentatonic those same notes are 5th position minor penatonic (albeit with a different starting notes). Same for 1st major and 4th minor, and 12 major and 3rd minor.
Glad to hear you're planning to check out the app! It includes scale training for major, minor pentatonic, blues, and a few more. If you notice any scales missing that you'd like to see added, feel free to reach out — I'm always happy to improve it based on feedback.
Bending takes a bit of practice but it’s not terribly hard. Here are some general tips for absolute beginners that are based simply on my anecdotal experience as an amateur player:
1. Don’t start with a wooden harp like marine band. The metal and plastic ones are typically a bit easier to bend.
2. One hole at a time. Ensure you can exclusively blow in a single hole to practice
3. Lower notes are generally easier to bend than higher notes
4. Make an O with your mouth and have the tongue float in the middle. Start by pulling, not pushing, in my experience bending on intake is slightly easier than bending on blowing out.
5. Tighten the lips and decrease the size of the O to increase pull force on the reed to create a bending effect, and also tighten the airflow chamber above your tongue by pulling your tongue back and up, then loosen it by moving your tongue forward and down
This tool looks great for helping improve once you’ve been able to perform the initial bend. Excited to try it out!
> Lower notes are generally easier to bend than higher notes
One thing to note (pun intended) is that you can only bend the higher of the two notes in a hole. On the lower half of the harmonica, those are the draw notes. But the upper octave switches these around. The blow notes are the higher ones there, and those are the ones you can bend.
> you can only bend the higher of the two notes in a hole
This only holds true if you don't count overbending.
Overbending works by forcing the "wrong" reed to play, e.g. forcing the draw reed to sound when you blow while the blow reed remains silent. Overbends nicely complement normal bends, but interestingly, overbends are a half-step higher than the highest reed in the hole.
> you can only bend the higher of the two notes in a hole
Do you know why that is?
I tried to look this up but wasn't successful. I remember it has to do with the lower pitch reed starting to vibrate along with the higher pitch reed, pulling the two notes together. But I don't quite understand the physics behind it.
If anyone find this, I am all ears! (Figurately and literally.)
While searching, I did run across this wonderful video of Toots Thielemans and Elis Regina:
https://www.youtube.com/watch?v=909HG10GLhE
And completely off topic, that somehow reminded me of my favorite live version of Ride Like the Wind:
https://www.youtube.com/watch?v=iYofDL0QnBE
No harmonica there, but everyone was having so much fun together!
> Don’t start with a wooden harp like marine band. The metal and plastic ones are typically a bit easier to bend.
OTOH I find the Marine Band Crossover (with a bamboo comb) to be probably the best bending harp out there due to it receiving detailed factory setup.
> Lower notes are generally easier to bend than higher notes
Additionally, you'll probably find a lower key harp to bend better, at least to a point. I feel like an A harp is the sweet spot for bending really well without being so low that it starts becoming difficult. G harps are good too, but require you to dig deeper to get a good bend.
The reason that wooden combs are harder is because the wooden comb swells from moisture (e.g. your saliva) and creates micro-gaps which subsequently requires increased draw or push force from the end user to perform the bend.
They sound the best though!
This is the best explanation I've found of the mechanics of pitch bending https://youtu.be/Fp-GxEaChr0?si=-E9uDTQx51gtnd9C
Essentially, match the size of the resonance chamber in your mouth to the note you're trying to bend to. This is different for every note you bend. You can find the right size by making "hissing" noises while breathing in (without harmonica) and matching the pitch.
I love seeing projects that shed a little vignette on a wide world I had no idea about! Thanks for posting!
This is great. Would have loved it when I used to have fun with the harmonica.
Here is a suggestion. Display a graph of played-frequency vs time. Then I can compare visually how my bending performance improves over time.
Thanks — great to hear you liked it, and that’s a really smart suggestion!
Actually, you've inspired a related idea I’ve been thinking about: since the app already shows a magnified pitch view for each target note, I could track how accurately each target is hit — not over time, but per note. That means collecting cent-deviation stats every time a target pitch is active.
For example, if you’re working on bending hole 3 draw down to F#, the app could keep track of: - how many times that target was attempted, - your average deviation (in cents), - and your best attempt so far.
It’s not a full frequency-vs-time graph, but it's very focused feedback — and could motivate practice in a very concrete way. I’d love to make this part of a future version. Thanks again for the spark!
Excellent. Your idea will really help with practice. You could maybe track
- how many times that target was attempted
- How many times you got there (green)
- How many times you almost got there (yellow).
- How many times you failed (red).
This is cool! I made a similar app, but for guitar. However, I couldn't quite figure out how long I should sample. I wanted to make an app where it will play an interval and then you need to play it back on the guitar. If you can get this to work on a harmonica, I should be able to get it to work with a guitar. Will likely use your source for more inspiration, thanks!
Thanks! That sounds like a cool idea too. In Let’s Bend, I also included a scale training mode, where users can practice playing along with different scales. Maybe that could be useful for your project as well. Feel free to dig into the source code, and let me know if you have questions!
I know what a harmonica is and also what bending usually means, but was perplexed at why someone would want to bend one except out of destructive anger.
Damn language barrier, I thought this was about the accordion
Harp player here. When I first started playing, I had a Gindick's book, Country and Blues Harmonica For the Musically Hopeless. This was maybe 35 years ago. I would recommend that book and the tape (cd? mp3?) that comes with it, for beginners. You can't see the notes you are playing on a harmonica. You have to hear them. You start by playing clear single notes and then shaping the note by articulating eeeh-yah or something similar and the note magically bends. You have to hear the note so you can tell if the note bends. It is very organic, and I don't think an app will help much. It may confirm what is happening, but it is not going to help if you can't do it. Personally, I played along with Little Walter's greatest hits on my hour long morning commute, and eventually it was just natural to bend the notes at the right time. My advice is to look for Jason Ricci on YouTube. He has hundreds or thousands of videos on beginner to advanced subjects. He is a weird dude, but I've never known a better teacher.