DIY SYNTH VCF Part 1: Analog Filtering Basics

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In this series, I'm taking a detailed look at how to build an analog VCF from scratch. To keep it as beginner-friendly as possible, I'm explaining what all the components do in detail.
This first part deals with passive first- and second order high & low pass filters. If you want to follow along, here's a bill of materials:
1x 1M mono potentiometer
1x 1M stereo potentiometer
1x 47k resistor
2x 10 nF capacitor
2x jack socket
Chapters:
00:00 Intro
00:42 What's a filter?
03:50 Oscillation basics
06:16 Low pass analysis
10:57 Low pass build
12:49 Moving the cutoff point
14:33 High pass analysis
17:44 High pass build
18:05 Higher order filters
19:20 Second order low pass build
20:40 Outro

[@adam.recording]

please don't stop these series, I'm learning how to start building my own synthesizer from your videos and you are really good at explaining things

[@TheCultofshiva]

Yes, these videos are great!! Really appreciate it ❤

[@dirter56]

Ok, you are the Bob Ross of synth theory 🖤

[@THE_ONLY_GOD]

LOL…don’t insult him

[@daBuzzY90]

This is honestly my favourite youtube channel right now. Great stuff.

[@questionman5]

Comments like this make me subscribe instantly.

[@cellbiol7298]

if these/such videos had existed 40 years ago, my life would have been different (this is the biggest compliment i can possibly make)

[@ryanshea5221]

Absolute best fundamental explanation available!

[@spagamoto]

I swear with these videos and W2AEW I'm privileged to sit on a veritable goldmine of practical knowledge. Thank you...!

[@Blah53455]

Oh my God dude, I've been trying to understand this for 3 or 4 years now after going to school tomget electronics degree , I ran into the exact problem you stated at the beginning your pipe and balloon method just helped me understand this more than my studying in the last half decade. Your an amazing teacher man , another vid going in to my pouch

[@trevorscott3275]

Wow I'm a Computer Engineer major and you do a great job at this than Professors. Great job man.

[@rob28803]

Nonsense. At uni, you should’ve learned all the math behind it, Fourier transforms, Nyquist, analog filters, digital filters and sampling. You would have to know all that to implement it digitally in a computer. This is a good practical intro, but with detail cut to near zero, for noobs. Your post is a meme, I see this kind of comment on just about all these kind of sites, and it can’t possibly be true, unless you slept through your degree.

[@ff-qf1th]

@@rob28803 uh? don't so goddamn consescending. Professors are often boring and have terrible explanations. Moritz Klein has very simple explanations here- which you note correctly that by doing this, he does have to omitt a lot of detail, and all of the maths involved. But that's just it- he is only omitting the hard theory. These videos are meant to be for practical purposes. And I understand that you already know this, and you were just criticising the commenter here for comparing Klein's work to that of a professors- but I would argue that the commenter here is also right. I think that Klein provides such a solid foundation in these videos that all that is missing is the math. I think he could easily explain that here as well, but he doesn't, because most are uninterested in the maths when they come to these videos. The commenter here was simply praising Klein's excellent teaching ability, and I believe he is right in doing so. I've tried to be civil in my reply to you here, but seriously dude, you need to touch some grass. stop being such a STEMlord.

[@dieSpinnt]

@@ff-qf1th It is true, that this is a good entry into the matter. But also don't talk bullshit. If you study physics or something-with-e or computer science and you are not fluent "speaking" the math behind the physics you won't survive a semester. If you talk to your professor about the water analogy he will probably drown you(joke). In contrary, if he explains the physics behind electron movement, the endeavor of load carriers to balance each other out with water analogies he will probably get fired(no joke, fired by Georg Simon Ohm himself, turning around in his grave.) Also if rob would criticize the video creator his comment would be over the top ... because why would he watch something he knows clearly in depth and then comment his frustration? That would be worth of a "STEMlord". But it is NOT like that! He criticizes the brain-empty comment that absolutely does not reflect reality, made by Trevor. Further, there is absolutely no problem here with Trevor having no clue and his(!) professor not telling him about the intricacies of electrical engineering and the physics behind it, because he and his prof are COMPUTER SCIENTISTS. Saying "than Professors" and not "my", the plural is the nonsense here. Oh and BTW: Next time, you or Trevor or me or Rob are building a filter ... despite the knowledge shown in the video here ... we need that f'ing math. Or what, a professor, a nanny?:P P.S.: Calm down. The ethical standards that you apply to others(here by misunderstanding?!) will help nothing when you dimension a filter, next time. Next time? I doubt this will happen in the next 4.32×10^17 seconds. Excuse my rant, getting excited doesn't make sense anyway. Either do it or let it stay(i mean electronics).

[@coolboy0851]

@@dieSpinnt Stop being such a try hard. "fluent in math", mate no one is fluent in math but mathematicians, electronics is not maths. All we care about is can you build a circuit, you use the equations as and when you need them, no one knows them all off by heart. Stop trying to seem intelligent in KZbin comments and stop scaring people off of electronics. This series is incredible for showing how to actually apply concepts, far better than university ever was.

[@danielfernandes1010]

Your channel is a treasure trove to me. I have been tinkering with electronics as a child, and later when I got into music production, I wanted to learn how circuits can generate and manipulate sound. I searched all around, but never found something that truly satisfied this longing in my soul. I wasn't so interested in blindly building these circuits, I wanted to know why they were designed that way, and why they worked. A few months ago, I found your video on building a compressor and after I watched it, I knew that I had finally found what I had been looking for. Thank you for these videos, you rock!

[@FerniFF]

I've been fascitinated with filters and dipping my toes into DIY now. I knew a mix of resistors and capactoiors create filters, but I always wanted to know how these two componots remove frequencies. Your video finally taught me, subscribed!

[@WowUrFcknHxC]

I like referring to the harmonics of a square wave as overtones. It gives this kind of intuitive understanding of what harmonics are.

[@EvilDragon666]

Lovely explanations! One minor nitpick though - filter cutoff frequency is not where the filter starts filtering, it's where the signal has already dropped off by 3 dB from the passband unity gain.

[@DKH712]

You really have a talent for explaining. I always wondered how my synths actually work, but I couldn't find a source that was deep enough, yet understandable enough without a background in electrical engineering. I think you've successfully hit that sweetspot. Keep up the good work! Thanks!

[@sgrimm7346]

Remarkable..... I've been into electronics (professionally and as a hobby) for over 40 years, and I've never heard such a clear and concise description of filters like this. You, sir, are a gem to the hobbyists and DIY'ers. I am seriously considering joining your patreon to help you continue your series, as well as other projects you might venture into. Please keep up the excellent work and dissemination of this information.

[@seankerr1187]

You just taught me more in this video than 4 weeks of an intro to circuits class did

[@MrBEnIbb]

Wow thank you!! This was really good made and understandable. Did not have the components at home, but a single capacitor. Was just holding it between two mono jacks, a cable between the ground and there was a high pass 🤩🤩🤩

[@prettypointlessvideo]

Your channel is fantastic. I'm building an analog drum sequencer atm and I'm still in the schematics phase because I keep getting ideas from you :)

[@stephenparry6811]

possibly the best youtube series on diy synth building

[@ff-qf1th]

Damn, your ability to convey all of this knowledge in your videos is outstanding. But something I don't think you get praised enough for is your aesthetic- the lovely wood table, the clean drawings to accompany every explanation that helps the learner visualise all of these concepts, the little electronic components scattered around the edge of the screen... It's beautiful. your videos are so aesthetic

[@MoritzKlein0]

thanks, i appreciate it!

[@Gary-vo9rm]

No kidding, great videos! Finally, someone that doesn't present a bunch of formulas, I have those. Watched a recent video of classical musicians, instruments in hand and ready to go, listen to a basic theme. A blues musician started playing along, but the orchestra was baffled. No sheet music. I felt embarrassed for them. The blues guy "understood."

[@oppositefields5567]

Great storytelling... love the pipes, balloons and pressure analogy to describe how components and circuits work. Well worth following or bookmarking this mini series.

[@BBayjay]

Hey man, the placement of components on the left and right side of the paper was a friggen excellent composition choice. The quality of the video is so high that it almosts looks like you are looking at a powerpoint with borders and art. It's fascinating.

[@MoritzKlein0]

thanks man, appreciate it!

[@wyzerdG]

Your method of explanation is truly exceptional. Learning from you is easy...thank you so much and please continue.

[@mrpoodoboo6785]

You explained filters better than my college electronics professors

[@pydron]

This is a fantastic video! I'm looking forward to seeing the rest of the series and your other videos.

[@antegulin9050]

Your videos are incredibly effective and enjoyable to watch. Please keep doing what you're doing, you're super successful at supplying knowledge to thousands of enthusiasts around the world.

[@scholasticdeth]

Explained so well, I am just a week into this, home education now

[@warpigs330]

These videos are so wonderful. Great level of explanation for those of us with familiarity with what filters do but not how they work. One of the hardest parts of explanation is estimating the level knowledge your audience has.

[@monoamiga]

Are you an university professor? You should be. You're a genius teacher, Moritz. Thank you.

[@annonymousname2.0]

this is extremely well produced and presented. i will definitly be watching your vco series

[@kabed9413]

Ehy man I've just discovered This channel and I'm already in love, thank you!

[@sivoltage]

Genius! This explanation is excellent, its really made me understand filtering. Keep up the amazing work.

[@albert4392]

Thank you for making these high quality video and sharing the knowledge with the community!

[@pressplay3243]

Finally a simple to understand synth DIY channel! You even added the components in the description. I can’t wait for more of these!

[@DragonDrummer2]

Yes!!! This is what i was looking for last semester! Thank you for putting out some stuff for me to play around with during my circuits courses!

[@LFOVCF]

Your analogies, and explanations, are absolutely marvelous! I now have a far greater understanding of filters, and electronic principles.

[@nathanoises]

thank you for doing this series, I already builded your VCO and it's sounding great! , your videos gave me the confidence to finally start building my modules.

[@iggzistentialism8458]

REALLY well explained! Thank you for taking the time and effort to make these videos.

[@IpickedTheR3Dp1LL]

Thank you for doing this. It really brings a lot of concepts together within my degree. Awesome job!

[@hakonsoreide]

By far the best and most educational lesson on how filters work I've ever seen anywhere online. Very well explained, and even if I didn't already have some basic understanding of electronics, it would have been easy to follow. Well done. This may now be my favourite KZbin channel after just watching one video.

[@jerometrachet2299]

Moritz, this is such a powerful work you did! Everything is so clear when you explain! Merci beaucoup!!!

[@CircularMirror7]

Thank you for this series. You are really good at explaining how and why these circuits function the way they do. Great stuff keep it up.

[@AnalogFunk]

This is fantastic. You are a great teacher. Goes deep yet easy to follow.

[@richardbrookes7336]

Fantastic clarity of concepts using water and pressure analogy. Looking forward to the VCF part 2 and the resonant circuit. Great stuff!!

[@griffzero]

Glad to find your channel, I've been wanting to get into building synths and didn't know where to start, but your videos have demystified a lot concepts for me.

[@lucienrapilly6407]

Great as usual, can't wait for your explanations about active filters...

[@maveru-music]

Man, you are the coolest! Don't stop these series please!

[@radicalfreq]

Big up uncle Moritz! this is hands down the best series in town, cant wait to watch all the follow up videos

[@slayer9126]

Fantastic information! Been going through your other filter videos and while I'm vaguely aware of most of this from my Uni, your videos truly make things click and make audio filtering and the formulation behind it really make sense. Truly appreciate your efforts! Keep it up!

[@danieldeatcu5986]

Great explanations! You have good materials on your channel! Love to see more. Thanks!

[@philipallen4230]

I'm so glad I found your channel, these videos are really interesting. Your explanations of these concepts are so clear and concise it's easy to follow and I have learnt so much from just watching a couple of your videos. Looking forward to watching them all. Thank you.

[@tshupenia8940]

I’m in love with this series!

[@omnaraiya]

Loving this channel. Best explanation I’ve seen on this subject.

[@Xyz-77]

I have been looking for a good channel about diy modular synths for ages. Now I finally found one, so I subscribed instantly. Please keep these series of videos coming! They are really the best pieces of information about diy modular synths out there.

[@latchodives]

Amazing video! I’ve always struggled to develop an intuition about the water analogy and it all clicked together now! The balloon metaphor is great!

[@lozD83]

Possibly the best video I've ever watched on KZbin. Massively educational and insightful. Well done indeed and thank you 🙂

[@stemmodular]

One of the clearest explanations I have seen. I am an EE but never heard the balloon analogy somehow. Great work!

[@THE_ONLY_GOD]

So increasing r makes less current get to that capacitor and thus the capacitor fills up more slowly, and because it’s filling up slower then it can absorb pulses of voltage that are longer (lower frequency waves) as r increases. Correct? Thus it’s not really practical unless the output is actively amplified in an inverse relationship to amount of r?

[@murraymacdonald4959]

Great stuff. You explained it very well with good production quality. Thanks

[@cpuchip]

That was a beautifully simple explanation and examples on filters!

[@dawsonzinza1671]

I love your drawings. Your illustrations are far more clear and understandable than my electronics professor's scribbles. LOL. Thank you for your circuit explanations.

[@AgustinDavidF]

Fantastic, as always. You are a very good at teaching. Thank you, Moritz!

[@magicmastera]

What a cool explanation. Never have seen it so easy ans understandeble. Thank you. 😀👍🏼👍🏼👍🏼

[@StormP666]

One of the best explanations of electronics

[@tyhodson]

Fantastic! I can’t wait to watch more.

[@dreamyrhodes]

Very cool explained. I think you once said that you're not a professional, maybe that's why you are able to explain it so that amateurs can understand it. Before finding your channel, I often watched GreatScott but he sometime's too short cut with his explaination. More like, take this chip look in the data sheet that means we can do this and that and then it works, while you explain it really on the low level what I especially like because I find it easier to understand when I really can "see" (even if it's water analogy - that's certainly not always 100% physically correct but much much easier to understand for the normal person) what's going on in these thingies. Please keep up the great work with these videos!

[@MoritzKlein0]

thanks, very glad you like the videos! and yeah, i mean i'm basically learning about most of these things as i make these videos - i guess that's why i'm being extra-beginner friendly!

[@dreamyrhodes]

@@MoritzKlein0 Which is a good thing. Thanks for doing this!

[@hnatyshyn]

It seemed a long explanation at first but then every bit is useful at the end. Great video.

[@streck0486]

Wow. This was incredibly informative. Well done!

[@jiffypoops]

very well explained! Good job ! Will clearly look at future similar videos

[@aprilfreitas8683]

By far the best explanations of analog

[@jean-philippefalcon3238]

I've watched almost everything youtube had to offer in terms of D.I.Y. modular synth video and your videos are the clearest and most accurate I've been able to find so far! Thank you so much for all the great videos you are sharing.

[@jfjlive]

thank you for sharing!!! this is wonderful Moritz!

[@aerofart]

Great subject, perfectly explained!

[@synthsandthings1480]

This is the best video about (synthesizer) electronics I've seen... ever.

[@eyeball226]

You've created a valuable resource here, thank you so much!

[@mrtessellate]

Outstanding course. Many thanks

[@hakonsoreide]

I actually just tried this. When I watched this, I wasn't actually thinking of making a filter, but I wanted to make a passive slew limiter for a MIDI to CV converter that I recently built as a DIY kit, and of course this works as a simple slew limiter too. A low-value resistor (around 100 Ohms) and a capacitor somewhere between 10 and 40 µF seems to work great to smooth out the edges of CV outputs which would otherwise have had 128 discrete values, making it sound very harsh and digital. So much easier than any other schematics I've found for slew limiters. Thanks again.

[@selectedacre]

This is superb. I can't thank you enough for sharing your knowledge. I'm sure it takes a great deal of time to develop and produce your videos. you have my gratitude. Very much looking forward to the continuation of this series. I got into electronics so that I might build my own filters, but have yet to find a sufficient resource to facilitate my achieving such a goal... Until now. Thank you again. And again... Several more times. :)

[@MoritzKlein0]

thanks, much appreciated!

[@sohamshah3128]

I was learning how to make my own hardware equalizers and compressors and then I stumbled upon this. I just want to say what an excellent analogy and teaching style you have. Kudos, please keep making this, I would love more hardware plugin related lessons as well.

[@mukul1230]

Waaw u have explained it so well ...i never understood filters in the classrooms...thank u

[@knuteri3]

This is a great explanation! In the past I have also used the idea of a voltage divider with one resistor and one capacitor, where the capacitors resistance is frequency dependent. This has also worked well as long as I have explained a normal voltage divider first (volume control), but I think I will steal your balloon analogy for future use! :)

[@patburnett8073]

Well done ~ will be sharing this with my Introduction to Engineering students next quarter.

[@MoritzKlein0]

i‘m honored!

[@hek_music]

I've been building my own synth from scratch for 2 years now. I had no background at all. There is a lot of usefull info on the internet but this channel is super clear and educative.. Thanks a lot!

[@ZocXer99]

Really amazing video extremely detailed and good described. I enjoyed watching it

[@strandedinanisland457]

Wow fascinating analogy. That's about two undergraduate courses worth of material and I used to teach some of this. The high pass filter I would explain by the capacitor charging and discharging.

[@ShawnyDsMusic]

Man what a fantastic video. Great work!

[@watchclark6482]

Nice, thanks for making this so clear and easy to understand.

[@PharoahJardin]

Thanks for the clear video. I have to mention that passive filters can resonate though. For instance a simple RLC displays resonance for some values of R, L and C.

[@jondough76]

Very interesting and informative video!

[@andreykotelnikov8352]

Thank you very much for your work! you really help to figure it all out!)) I wish there were more videos like this! Thank you so much))))

[@ttm5816]

Thanks Moritz for really good info!!!

[@Mosswurk2]

This is very well explained 👍

[@DuckTronic]

Thanks! Very nicely explained!

[@benjaminlehmann]

That was great. Thanks for the explaination.

[@matthewlareau8051]

Finally someone that puts electronics simple enough for me to understand , thank you !😉

[@mohanjanisthere]

If loopop and look mum no computer had a baby. Love the channel

[@technoshamanarchist]

I think LMNC would actually be the baby ;)

[@henryrobinson9837]

thanks for the video man, i appreciate it, i'm in a different field of study but it coincides, i'm an auto tech and hade been making filters for automotive ocilloscope diagnostics, actually working with very low frequencys

[@cj-er4xr]

Thanks for your GREAT videos! really well done!

[@aipsong]

Excellent, informative video - thank you!!!

[@nelsone9520]

Muchas gracias por los subtítulos en español! Saludos Moritz, sus videos son magníficos!

[@soejrd24978]

Looking forward to the next one!