Designing a simple audio compressor from scratch

[@UnwelcomeGuestVideos]

The extra effort here with the animations was definitely appreciated on my end! I love that you slipped a side chain feature in at the very end! Beautiful stuff Mortiz!

[@MoritzKlein0]

glad to hear - doing the animations is super fun, will definitely expand on this in the future.

[@mbrombert]

@@MoritzKlein0 Agreed. This new approach is really well done and looks great. Thanks for the awesome content!

[@c1ph3rpunk]

@@MoritzKlein0 what did you use for those animations? They’re super helpful.

[@executorarktanis2323]

@@MoritzKlein0 Animation helped me a lot here thanks

[@San.Tarcisio]

animations super helped

[@erich1394]

I am a hobbyist C++ Audio DSP programmer, so I understand exactly what a compressor does and the functional blocks used to control it, but the actual breakdown of specific implementations using electronic components has always eluded me. Looking at electronic circuits without experience made it difficult to see the "boundaries" between components. Your video has helped me realize that obtaining generalized knowledge of common audio electronics sub-assemblies and the ability to identify those sub-assemblies is the key to my understanding audio electronics in general. I feel significantly less intimidated about designing audio circuits after watching this video. Thank you so much for the work that you do!

[@simonlinser8286]

Yeah, thinking in modules i guess. It's what makes any tear down or circuit analysis video good, is them kind of circling part of the board and saying what it is and then the individual components, and it's the right way to think of circuits. I guess the only difference is when you don't know and see a circuit board it looks over overwhelming but if you can break it down into its parts or sections it's more approachable.

[@jacobhn2]

I hacked a Yamaha compressor GC2020 to have a 10-second release time, it was so that when I watched a movie the sound was absolutely perfect and without it going beyond the dynamics and when the scenes with low volume the compressor slowly turned up the volume. Attack time=0, Release time=10sec or less

[@widepen93]

I'm in a similar boat designing a pi DSP drum machine+synth. Care to share your favorite resources of getting to understand compressors? This video helps but im trying to soak up some more. Thanks!!

[@TheRailroad99]

Yeah, that's what engineers (have to) do... Divide and conquer. Doesn't matter if it's HW or SW. chop it into simple modules and test them thoroughly

[@pollo.888]

Ive taken the full electronics series of courses in my degree track. Stumbling across these videos makes everything I've learned click.

[@adamdev9391]

2:02 - My god. This is the best explanation of compression I have ever seen

[@famitory]

i have been looking for a good compressor circuit that didn't need any fancy components (monolithic VCA chips, OTAs, special FETs , or LDR tuning) for a long time and finally here one is.

[@juanvicentedelrio716]

I have been on the audio scene for over thirty years, I mean on the electronics field rather than in the use of the machines, and believe me...I have never found a book or document that explains in both easy and comprehensive way the subject you have gift us on this video. Not only the practical design and the theory behind (without getting into heavy design issues) but, also, the perfect animation and perfectly chained explanation. I have subscribed immediately to your channel. Thank you for your work.

[@chitlitlah]

I just built this circuit with some changes for my guitar. Since unamplified guitar voltages are a few hundred mV at most, I only used one diode on each side of the diode bridge and didn't attenuate the signal going through it. Other than that, I replaced the potentiometers with fixed resistors since I don't have any pots on-hand and changed two or three resistor values, but that's it. It works really great as a compressor.

[@juanbarcelosalves]

hey, I'm trying to recreate this circuit for the same purpose as you, for a electronics class in college, I would very much appreciate if you could share the components you used, specially the OpAmp, since all the OpAmp I own strugles with such low voltages. Thank you.

[@lukaswalczak93]

This is exactly, how to learn analog circuit design. I absolutely love how you describe every single detail. That shows that you truly understand what you are doing, making it really really helpful for others to understand these concepts. So helpful, thank you so much.

[@elluisito000]

As a pedal designer, compressors have always puzzled me. This is a very nicely done video describing how they work. Thanks

[@chrismathewsjr]

i don't work in music any more but one of my favorite things is asking "pedal designers" simple things like "what does an NPN transistor do" and "how does ground work"?

[@executorarktanis2323]

@@chrismathewsjr lmaoo how does it go then

[@dieSpinnt]

@@executorarktanis2323 I am more basic. I would first ask why he uses his assumptions(or delusions?) on his hypothetical designers with an example in the style of the Brothers Grimm? What stupid (and the totally unnecessary blanket insulting taunt) stuff he's talking up there? A totally insane straw man about how transistors work... thrown out of context to make himself important. Great! Now we all know the kind of people he dislikes: music pedal designers. Did someone ask for that? Or does this childish BS interest anyone? As @elluisito000 said, it is a very interesting topic. Just search for "boss compressor schematic" or "Formant", "Parametric Multiband", "Hollis", "Teletronix", and so on. Not a bad idea to learn from the experts ... or ancients ... or ancient experts!:) Have fun playing and soldering, all (including our braggart).

[@executorarktanis2323]

@@dieSpinnt holy thanks man

[@matturner6890]

@@chrismathewsjr I'm not an obstinate prick anymore, but one of my favourite things is asking guys like this simple things like "how do you talk to people at parties without them all leaving"?

[@lettersnstuff]

I’m not sure how I haven’t had your videos in my recommended yet but I’m genuinely excited to have found your channel

[@vinjetho1609]

i've been wanting to learn about signal processing, and electronics in general, for a while, but it all just seemed so confusing. the animations and visualizations in this video were amazing, and helped finally feel like i have a chance at understanding things! thank you so much for this amazing video!

[@punman5392]

You should modify the peak detector to use a precision rectifier instead of a half wave single diode like you use. That way you can reuse the circuit for an envelope detector to control a VCF without noticeable wobble when playing bass frequencies. The big downside to half wave peak detectors like that is that with bass frequencies you tend to hear a lot of wobble in the envelope as it’s only acting on half the peaks.

[@BristlyBright]

Just paused at 8 minutes to say WOW! The animations! They really help to grasp the flow in a much easier way! Thank you!!! 🙏

[@DiVoidationStudio]

This is the best stuff about electrotechnical principles in music. This beats all that I've learned for several years in my engineering university. Just excellent and very inspiring! Thank you!

[@payloh_3328]

Agreed awesome stuff

[@Signal_Glow]

Explanations are very good with animations helping people visualise what is going on. Those who are into pro audio side of compressors might like Gyraf Audio diy 4k compressor explanation as it shows pretty simple, typical VCA compressor, explaining how each part works and interacts with others in easy to understand details. Also shows typical balancing circuits, use of IC based parts like THAT VCA's, detectors, etc. Ian Bell of Custom Tube Consoles had or has example of simple opto compressor, i'm not sure it is still there although whole diy part is more than worth checking, same for Gyraf's. I will always be thankful to people like Moritz, Gyrad and Ian Bell, not many take their free time to explain this matters to beginners, or even more advanced pro audio electricians/designers. Many thanks, wish you all the best in 2023.

[@prsm3]

Diese Videos sind einfach so informativ wie eine Doppelstunde Physik Leistungskurs, wirklich sehr gute Qualität und man kann einfach alles so leicht verstehen!

[@JamesPearson]

Brilliant Moritz, this is such a great circuit and beautifully explained as always. The animated visuals are a treat, thanks for all the effort with that - I know it wasn't easy. Looking forward to building this sometime. Happy New Year when it comes :)

[@MoritzKlein0]

let me know how it went once you do!

[@SomeWeirdCat]

This single video is more useful than any of my circuits classes ever were

[@zmix]

Nice Work Moritz. at 26:08 you're describing a phenomenon of hardware compression: the exponential / logarithmic charge / discharge curves of capacitors, and nearly touched on the difference between hard knee and soft knee compression (though that is usually implemented by adding a diode in series with the final CV. I'm subscribing..!

[@MrShmazoo]

I’m a current EE student with a budding passion for computer music and find this video incredibly inspiring. Thanks for the detailed explanation and impeccable animations!!

[@5eZa]

sounds pretty good. i think fully rectifying the cv signal would catch initial negative transients that you are missing and improve attack response. that's the only thing i would add

[@MoritzKlein0]

you mean rectifying the VCA's output before detecting the peak, right?

[@5eZa]

@@MoritzKlein0 I mean fully rectifying the audio input signal you are using to detect the peaks. if the input audio signal has an initial negative transient instead of + then your VCA signal will be delayed by that missing half wave

[@ArchetypalCat]

Dear Moritz - viele Grüße aus North Florida! I'm a retired programmer and hardware engineer. I studied electronic music and sound recording in music school years ago. (Among the first students permitted to have the synthesizer as their major performance instrument, I was also fortunate while there to meet some of the biggies: Robert Moog, Ray Kurzweil, and Don Buchla. I've been doing electronics stuff off and on for over half a century *sigh*). I'm not mentioning all this to "toot my own horn" as we say in America, but rather to provide a context of why I find your KZbin presentations so very significant in this field. Not only is your modular approach easy to follow, but also the way you simplify each essential step and provide clear diagrams, making each video approachable for any skill level. (And, having lived in Deutschland für einige Jahre, und Englisch unterrichtet, muss ich ganz ehrlich sagen, dein English is absolut spitzenhaft! :) After years away from synths (due to work ;/), I've come full circle back to learning about them, to see what's current. The Euro Rack world has exploded since I first glanced at Doepfer Musikelektronik, GmbH (hey - another great German company :) ... and the world of electronics has become so much easier with stand-alone modules, microcontrollers, I2C, I2S, etc., the Arduino platform, and, of late, the Raspberry Pi. But especially useful is the amazing content on KZbin. I've watched a ton of presenters here - your work is among the best. And I don't say that lightly. Since you're doing kits of your own and are already in the advanced stages of electronics design, I'd like to suggest a book for you (and your viewers, of course) - if you don't have it already. This 700-plus-pager is by one of the best (and oldest) experts in the field of audio: "Small Signal Audio Design, Third Edition, 2020" by Douglas Self, Routledge / Focal Press, ISBN 978-0-367-46895-8. It isn't a beginner's book. In fact, I'd say it's near the peak of the knowledge pyramid. And yet, anyone interested can learn from it, if they are persistent enough. It will improve designs, even those that aren't audio. By watching your videos, I've learned new things and remembered stuff I'd long forgotten. Just goes to disprove the old, (English) adage: you *can* teach an old dog new tricks :)) Dank You! Thanka Schoen! 😁 - Howard

[@MoritzKlein0]

hey howard, thanks for the nice comment, i appreciate it!

[@ArchetypalCat]

@@MoritzKlein0 you are most welcome, Moritz! I'm really enjoying watching your interesting work - it has given me some fun, new ideas. MfG -H

[@ahreuwu]

I'm a complete noob when it comes to electrical things, I can barely follow the "pipe" of the current, but you presented this in such a straight forward way that I think I understood it completely. Loved the visual aid, I already knew how the waveform behaves under the parameters but it was very useful for translating that into knowledge that's compatible with electronics. Your format is so approachable for beginners that it's making me want to keep learning about electronics and get into dyi audio gear, thank you‽

[@m3trom]

It is unbelivable that i try to make a compressor with sidechaning since last fall (without any succes), and your video is just came to my face and covers everything! This new animations makes a really nice illustration, and as i see you implemet this really well with motion. You are a really kind person to share this knowledge in a professional way. Perfect stuff! Deserve more attention.

[@JonDeth]

This is great and straight forward. There's so many ways to achieve compression that seeing a specific scheme broken down into an actual tutorial with the lab and circuit gives those of us interested an example of a clear pathway for our own designs. Because I am specifically desiring one for guitar ATM, I can see from your circuit a way to incorporate this theory of operation into a feedback path to buck some of my input buffer when the circuit sees an excess. As I understand it, you're demonstrating the implementation of multiple methods of compression for an overall more dynamic circuit and performance. *Anyway, this will definitely help me with the design I have had rolling around in my head.*

[@railfilm]

Hi Moritz, excellent job. Just a little add on. On every compressor one usually loses some level of the signal, therefore in the output stage you will need one more potentiometer to change the gain of the output stage to recover the original input level.

[@MoritzKlein0]

good call, will add!

[@timbeaton5045]

@@MoritzKlein0 You could also add a mix control between the input signal ("dry") and the compressed output ("wet!") which gives you instant parallel compression. Should be a straightforward output mixer stage between the two signals.

[@Wizardofgosz]

If you're actually compressing then you have to be losing input signal. Compressors make things quieter. But yes a makeup gain knob will compensate for that.

[@cls9474]

@@Wizardofgosz Not necessarily. Compression usually means: compression of the dynamic range, not the volume/loudness. Therefore: if you'd like to just compress the dynamic range (in contrast to limiting the peaks), then you'll need a make up gain.

[@Wizardofgosz]

@@cls9474 You have no idea what you're talking about. Compressing dynamic range is compressing some of the gain or the volume. Compression only makes things quieter.

[@nsfeliz7825]

you are a real electrical engineer. you are the sabine hossenfelder of electronics. no gbledygook no bullshit. i have zero respect foe 99 percent of audio experts . but you you. ypu are the man.a

[@gooball2005]

This was a great video! I especially appreciate how you went into your circuit design process, building it up on a breadboard and addressing any hurdles as you came across them. Great work!

[@jas_bataille]

You sir, by the noticeable loudness difference and perfect clarity of your depth and clarity of your voice, definitely know about compression.

[@thomasallen3532]

As someone who knows verry little about all of this but wants to learn more this was an incredibly helpful video and explained verry well! Thank you

[@doBobro]

Animation o_O. It's amazing how well fluid pressure analogy works here. Oscillating membranes are mesmerizing.

[@aduedc]

This works great for symmetric wave forms, which is most of the cases. Now, imagine you have a wave form which has negative peaks and no positive peaks, then the peak detector will never turn on. To solve this problem you need to place absolute value circuit before the peak detector, which could be as simple as full wave 4 diode rectifier circuit or its opamp equivalent.

[@anthonyhart7878]

The add level of quality was really noticeable with this one. This was a great video.

[@moliver_xxii]

circuit using diodes as variable resistors always make me happy and smile. they are always so surprising but work great. thanks!

[@Scanlaid]

So glad I found your channel. Went to school for mechE, this is basically all magic.

[@AntoineHoubron]

That is such a great video. The animations are first class and the oscilloscope capture is a great addition. Maybe inverting the colors between the audio waveform and the detector line would make the latter more visible. Interesting additions to the circuit would be : - selection between feed-back and feed-forward detection - a diode bridge to feed the detector - the ability to hit negative ratios by actually amplifying the cv input of the VCA - sidechain filters, low cut and sibilance emphasis - gain reduction range control. This is done by limiting or clipping the sidechain output - dry/wet Blend is fairly easy and very useful - make up gain is also a compressor standard feature Thank you so much for creating such educationnal videos, and for showing the world the actual behaviour of electronic components !

[@MoritzKlein0]

those are great pointers, thank you!

[@AntoineHoubron]

@@MoritzKlein0 you are the one to be thanked ! Also, i would strongly advise against the implementation of automatic gain compensation, as this feature is only present in software and cannot give exact loudness match, as it uses estimated levels. Plugin developper John Matthews made a really good statement about it in this video : kzbin.info/www/bejne/oqSlkH2capWFZrM

[@frankjrgensen1439]

This is by far the best explanation I’ve seen on compressors and the building blocks involved. Thanks a bunch!

[@YanDoroshenko]

The last time I've heard anything to do with voltages and stuff was at school, yet this is perfectly comprehensible. Might even try it at some point.

[@markhammer643]

As ever, very nice video, accompanying explanation, and pleasingly simple circuit. One needs to distinguish, however, between compression and limiting. Limiters direct the circuit to address the dynamic peaks, while leaving material below the threshold intact. Compressors attempt to achieve an overall average signal level, by limiting peaks in the manner you've illustrated, but also *increasing* gain when content is well below the peak threshold. In practice, the two can sound identical with adjustment of controls, but there can still be audible differences between them when controls are set differently. One of the phenomena compression can result in is often referred to as "breathing". Since analog compressors generally have no means to differentiate between pianissimo signals and background noise. they dramatically increase gain when the input signal is small. If the release/gain-recovery time is long enough, the gradual increase in gain during soft parts results in amplification of background hiss that sounds like someone inhaling - hence "breathing". The cure involves use of as pristine an input signal as one can provide, and as quick a gain-recovery as is plausible. Limiters typically do not encounter breathing. While not strictly true all the time, limiters often involve feed-FORWARD control, while compressors tend to use feed-BACK control. That is, limiters use the input to control the final result, after the gain is applied, while compressors tend to use the amplified result to adjust how the gain is set. That aspect plays a big role in achieving an overall average level-setting in compressors. Another limiter/compressor difference that may not be quite so apparent in the percussion example used in the video is the impact of instrument, or other, signal sources that either sustain or have long decay times. Although we may perceive such sustain or prolonged decay as smooth, it is actually filled with a great many little bumps, often referred to as "envelope ripple". When simple half-wave rectifiers are used to extract information about signal level, that ripple in the resulting control-voltage can produce small rapid fluctuations in output level (or filter-frequency, when used to control a filter) that can sound like "distortion" to the user; especially if used in conjunction with control elements that are able to respond to very quick changes (one of the reasons why photocells are often prized for some forms of sound processing). The solution is often to use better rectification, as well as averaging the detected signal level over a longer period; the goal being to make the control voltage resemble pure DC as much as possible. Again, as elegant as the circuit shown here is - and it IS elegant - it is really predicated on processing short percussive sounds, and would need more to be able to process longer-sustaining sounds without problem.

[@murrayedington]

Indeed, this isn't actually a VCA, it's a clipper / limiter. It's an interesting journey but opamp based voltage controlled gain is fairly straightforward. There would be a lot gained by doing some reading up front, rather than trial and error. The Art of Electronics by Horowitz and Hill might be a good place to start.

[@Wizardofgosz]

This isn't really true at all. There is no difference between compression and limiting. Limiting is just extreme compression with an infinity to one ratio and a very very fast attack. The only time a "normal compressor" adds gain to the quieter part of the signal that's not being reduced by the compressor is if you have a makeup gain knob and you're using it. Otherwise I can make a compressor with a wide range of controls be a limiter quite easily. My Urei LA 22 compressor for example. And plenty of limiters do have makeup gain.

[@markhammer643]

@@Wizardofgosz Oh they can certainly *be* tweaked and dialed in to sound the same, and yes there is makeup gain. But there is a difference between rackmount units, like your Urei LA 22, and floor pedal compressors, which operate like AGC controls on budget tape decks. In those circuits, there is not really any "make-up gain". They are aimed at a narrow range of output signal amplitude, both attenuating peak transients and automatically boosting signal level, when it falls below some threshold. FWIW, I built a pedal for myself, using the SSM2166 chip from Analog Devices (great great chip by the way). It's a general purpose preamp dynamics-control device, and can function like a limiter OR compressor, if twiddled just right. For instance, if I set the ratio to "infinity", but leave the threshold high, it behaves like a peak limiter, such that everything below the threshold retains all dynamics. If I set the threshold very low, and crank the gain, it behaves like a compressor, with very little in the way of audible dynamics.

[@DrTacoPHD665]

I did circuit design and filtering courses at university out of interest, but it never got to the point where I could see those principles being put to use in a real application. This is amazing.

[@snarfusmaximus]

This video was recommended to me by KZbin, probably based upon what I've been watching lately. I studied electronics over 25 years ago and this video has made me subscribe. Great stuff!

[@Zadagu]

I always wanted a video which explains how compressors are engineered and never found one on YT, to this day. Thank you very much! Finally I got some insights.

[@AndersWeijnitz]

Best compressor walk-through on Earth!

[@acdnrg]

This is awesome. The bonus part, sidechain, also explains very well why sidechain filters only affect the control voltage and have no influence on the processed main audio signal. One look at the diagram is enough. Bravo!

[@jacobrepp787]

Amazing, thank you for bringing this subject to life. Great graphics, animation and as usual clear and deep explanations.

[@cspower7259]

Loving the diagrams. Gives a really good way to visualize whats going on. Its kind of what my mind see, when looking at a circuit diagram.

[@geliasr2562]

Many thanks! I know the Brazilian real is devalued in relation to the dollar, but it's from the my heart.

[@MoritzKlein0]

hey thanks, i appreciate it!

[@juppster5694]

That was fabulous, thank you! I especially liked the 'rule of thumb' explanations around some of the feedback mechanisms, and the real-time 'scope traces of control and signal displayed together. The VCA is so simple and I wouldn't have thought of it - I'd be using something more complicated like a FET affecting an op-amp gain stage. In the olden days I think we might even have used a bulb-LDR optocoupler. Very nice work - thank you.

[@spencebarton2947]

Many audio signals from synths BECOME asymmetrical when they pass through a cap coupled stage. Any pulse wave with a duty cycle less than or greater than 50% will do this. Send a 90% duty cycle pulse wave into the DC coupled input of your scope. It *should* be symmetrical about 0V. Then change to AC coupling. The narrow phase of the pulse have a larger excursion above or below zero than the wide phase. This is due to the time required to charge and discharge the coupling cap. Even some of the example waves in this video show this. Since this is so, if you want your compressor to work well it doesn't make sense to throw away the negative portion of the wave. The negative half could have a significantly larger excursion from zero than the positive half. It's EASY to full-wave rectify the input signal instead. One or two op amps. These kinds of circuits are called precision rectifiers and there are probable a dozen different types available on the internet. That way you get accurate compression of asymmetrical signals.All the famous compressors and limiters derive the side chain from a full wave rectified version of the input not a half wave rectified version. It's so easy to implement it makes no sense to throw away half the signal and wave your hands about audio signals being symmetrical about 0V. We're only talking about $1 worth of parts.

[@spiesonmars]

Your use of animations is great - it really helps to understand what's going on in the circuit. Nice work!

[@Triggs-Music]

absolutely astonishing how well you put together this info.

[@Yotanido]

Not really doing anything with signal processing, it took me a couple minutes to remember how OpAmps even work, so a refresher would have definitely been appreciated. That said, you made enough comments hinting at their function that I did eventually remember :D Other than that, though, this video is absolutely brilliant. Easy to follow, especially with those animations.

[@naota3k]

As someone who understands the basics of music production/mixing, but is just _awful_ with electronics, this is incredibly insightful. I have always been curious how we were able to do things like compression, EQing, etc back in the analog/electromechanical days.

[@oveschleisner-meyer8139]

I love your clear and visually decription - great.

[@waporwave5066]

more straightforward than I would have thought, I could follow the thought process really well. I expected there to be a catch but it seems somewhat simple, maybe that's from how you explain it :)

[@rotoast8113]

Thank you so much for your videos. As an electrical engineering student I find it quite difficult to understand the fundamental (transistor, OpAmp) curcuits and their purpose in the real world. This helps a lot, because your explanations fit in so well with my current level of knowledge. Love your animations, too. :)

[@cwrigh13]

I'm amazed that all this can be achieved with a handful of components. Not an Arduino in sight!

[@AMTunLimited]

I was just thinking about this! I plan on making my own Eurorack in the new year and my first module is going to be ab envelope follower as it's one of the few things I don't already have on hand, and I realized that ducttaping it to a VCA would be instant compressor! Excited to watch this

[@AngadBagga]

I finally understood what a VCA is. Thanks.

[@TheBigChoppa]

Appreciate that you shared from the process of designing vs explaining a schematic! This definitely shed some light on a few basic ways compressors can have unique characteristics. Thank you for the hard work!

[@joshuakendall3965]

Wow, your educational videos are superior to all others. So elegantly constructed and informative. I thank you.

[@BennosProject]

Its the first time i really understand what a crompressor does! Thank you!

[@blacklion79]

Best explanation how basic compressor works I ever seen.

[@DrMoe.Lester]

I've been binging your videos. If only electronics at school was explained how you present it! Thank you so much for your efforts, looking forward to more videos.

[@heslip7042]

What a great video. The drawings and animations are fantastic. As an electrical engineer, I've very much enjoyed this.

[@DjDoggDad]

Figuring out how to make a sidechaininng compressor has been on my radar of projects i'd like to do and then stumbled across this awesome video! Thank you so much!

[@maxhouseman3129]

I am very impressed. The explanations and animations are top notch! Doing just digital circuits for living, that makes me smile 😍 Greets from an hw engineer

[@SirMo]

I was looking for a simple compressor circuit, and this is definitely above and beyond of what I need. But it's really cool nonetheless. The production quality is also off the charts. Great work!

[@marouaniAymen]

This is one of my best electronic related videos that I watched so far. It did give me some inspiration on how to multiply two signals together or how to do frequency modulation.Thanks.

[@infantino93]

Been getting into DIY pedals lately, I must say you may be the most concisely informative 'tutor' I've stumbled across. Learned a ton, thanks.

[@raphaelcochez3863]

A full 5 star explanation on compression and electronic background explanation! A possible extension of this circuit could be mono/stereo compression or multi-band side-compression by splitting the signals. Great work!

[@GilgaFrank]

Brilliant stuff, expertly explained. The attack pot in the feedback path seems to change it to a hard knee compressor. I'd make this switchable for when soft knee compression is required.

[@camjones9213]

What a great explanation of compression circuits - these videos really helped me whilst studying Audio electronics

[@migrantfamily]

21:42 I love that sound! I need to build this for my acoustic pedalboard.

[@vicopujia]

This why I like the most on the electronics field of knowledge. Amazing channel

[@FirstnameLastname-gl1hh]

Very thorough easy to understand explanation, great job

[@TheRailroad99]

Fantastic lesson! Thank you very much. The diode VCA is an interesting circuit. Diodes are great, but because they are non-linear they of course create their own set of issues and distortions.

[@Blah53455]

DUDE SUPER SLOW CLAP, what and amazing video, i will be sharing this over and over again brother, I love the way you even went in depth on the parts you ended up changing . This just doesn't just show you something , it shows you why you chose to coarse correctly . What an amazing video. I'm so pumped to see your others .

[@takislontras4563]

Finally !!! I was hoping you would touch the subject!! Awesome content my friend. My best youtube suggestion video in ages :)

[@kellerdev2905]

Wow, great ideas! Compressor is a must to make a nice mix, I've struggled with adding a little bit of soft clipping on a couple of iterations to increase the loudness this way, but that's much more professional sounding!

[@PORKCHOPSH]

Holy crap i think I actually understand compression now! Seriously, I can't wait to know what I'm actually tweaking next time, big big thanks!

[@delusionwalker8852]

Dude, you are amazing!!!!! You explain and show things just how I like it straight to the point, concise explanation no bullshit. Thank you so much!!!!!

[@stevenwilliams6258]

Nice explanation. My initial thought was why compress? Don't you want a dynamic sound? But, as you explained, this can correct the balance of related instruments for a more desirable sound. I just happened to see this and clicked - I'm an audio listener, not a musician or recording engineer. Thanks!

[@alexferguson5346]

Yo im a 4th year EE student, and this is the exact kinda thing I wanna do with the stuff im learning. Well as a hobby at least. The way you broke down the problem at the start was really helpful to see. Gonna buy some op-amps and mess around with a breadboard and guitar now.

[@oasntet]

I recall the various rack-mounted compressor/limited modules had a lot of indicator LEDs; it might be nice to have one that lights up when the peak volume exceeds the threshold, and between attack/release... Of course, they also had LCD indicators that showed the peak, threshold and output levels, but that might be tricky without adding some digital components.

[@StevenFines13147]

I definitely would like at least a single LED that would indicate when the compressor is, well, compressing.

[@MoritzKlein0]

that’s a great idea!

[@kesor6]

Maybe some of those multitude of diodes can be replaced with LEDs for interesting visuals.

[@dieSpinnt]

@@MoritzKlein0 Yeah, visual feedback is not just a bonus. It is essential for us dumb musicians ... Nur ein Scherz!:) Als ehemalige Kommunikationselektronikerin, Elektro-Ingenieurin, hobby-mässig mit Audio und Röhren-Elektronik unterwegs und Death Metal Gitarristin kann ich dir sagen, dass ein VERLÄSSLICHES und so weit wie möglich einfaches (und vor allem memorables, nachvollziehbar erlernbares) Feedback ein unschätzbar wertvolles Werkzeug ist. Nicht nur auf der Bühne, beim Soundcheck oder mitten im Gig beim Nachjustieren. Das macht den "kleinen" Unterschied beim Design von Profi-Geräten, dem Gehalt von investierter "Liebe" aus. Danke für dein tolles Video (inklusive der anderen), welches gewiss viele Menschen für unsere faszinierende Welt der Elektronik und Physik interessieren wird:)

[@ulfschoneberg6452]

Toller klarer Stil, tolle Videos, danke Mortiz!

[@kcbanner]

Have been watching this channel from the beginning, these animations are so good at explaining these concepts - this channel is a such a good resource!

[@electron7373]

Excellent presentation quality - you must put a lot of time and creative effort into each video. Thanks Moritz!

[@Tom-nf6xo]

Greatest video ever !!! Thanks for explaining everything step by step and how you have implemented it. Thanks again and keep them coming!

[@PeterJaquesMusic]

This is really great! I'm just diving into circuit design, so this was still over my head, but you explain things so well that I started to get it, even though I need to understand the real basics first. I'll definitely be checking out your other content! thanks!

[@Sharky_31]

The Grafiks are amazing. Well done

[@alemassa6632]

Beautifully explained, you're a great speaker.

[@victorsantanpagay5811]

Wow it's very simple at the same it's very effective good work sir

[@longdongsilver4719]

Your descriptions are, as always, clear and simple. And I love your animations.

[@hamlob]

This is the best video I have ever seen

[@kimjunkmoon2298]

I'd love to see how you would implement an automatic make up gain or automatic release setting. It's common on digital compressors but I suspect it would be harder to implement on an analog circuit.

[@MoritzKlein0]

would the make up gain would try to get the signal up to 0 dB? or what's the goal, normally?

[@kimjunkmoon2298]

@@MoritzKlein0 Well, the goal is to match the output's volume to the input's volume, usually rms volume. Normally, you manually do this after compressing a signal, but if it's automatic, the make up gain automatically adjusts as you tweak the threshold/ratio pots, allowing you to hear in real time the effect of the compression, instead of having to juggle two knobs at once to get an accurate view of what you are doing to the sound. My guess of how you would achieve this is by using stereo pots for threshold and ratio and doing some math to figure out by how much, approximately, the signal is getting reduced by and boosting it by that same amount.

[@javierpiles]

Animations were very helpful for the explanation! Thanks!

[@KingGrio]

1) THANK YOU 2) Cap charge slowing down could be a feature and not a bug, for certain applications, a compressor that slows down. Not quite sure where it'd be useful, but it's always fun to experiment. Might be nice on vocals to preserve the signal and not squash it too fast ?

[@michael-rommel]

Thank you, Moritz, for this outstanding video! It was one of the best that I have seen in a long time! Very comprehensive and comprehensible!! Tempted to get your series of modules just to support you in this effort!!

[@janpriskin9327]

Why you were not my teacher at electro school? I might progress 10 times faster. I nominate you for Nobel prize in education.