Roland TR-808 Cowbell Rebuild | Hacker News Reader

Roland TR-808 Cowbell Rebuild

frisnit.com

182 pointsherendin44 comments

It's difficult to overstate how pervasive the 808 cowbell was in early hip-hop, funk, and R&B music during the 80's. To this day it's a sound that pleasantly nostalgic and takes me right back to my younger days.

Something I always wondered about: it seemed like not all 808 cowbells were exactly the same. Some seemed to nail a very in-tune perfect fifth. While others were just shy of a perfect fifth, giving more of a sour sound which I think was more common.

In Bar-Kays' "Sexomatic," the 808 cowbell's pitch raised up a whole step to match the song's key, but it also sounds like a very in-tune perfect fifth: (3:55) https://youtu.be/rqWfERqQlk4?t=235

In 2 Live Crew's "Mr. Mixx On The Mix!!" the 808 cowbell has the more sour sound: (3:19) https://youtu.be/yNiAYpd1f84?t=199

The bread board project was producing an interval that was just shy of a perfect fifth, making it closer to 2 Live Crew's 808 in my ears.

I always wondered if slight variations and and manufacturing anomalies in the analog components accounted for this difference or if something else going on. If OP is in this thread, I'd love to hear your opinion and conjecture on this. (And I'd also like to thank you for the GREAT write-up and YouTube clip. LOVED this.)

Some of the 808's instruments/parts have trimmers, as mentioned below.

But generally for analog, component tolerances are either 1, 5, or 10%. 1% is pretty audible on oscillators, and 10% is pretty audible on filters.

So each instance of an untrimmed analog synth and drum machine will sound slightly different, even if they're coming off the same production line and using the same circuitry.

Component values also drift over time, so a contemporary 808 is not going to sound the same as it did when it was shipped in the 80s.

Basically analog's inaccuracies add character, detail, and interesting distortion. You can emulate them digitally, but emulating all of them accurately and convincingly is really quite hard.

I understand temperature affects the frequency of some oscillators as well. Is that a possible explanation as well? (I assume for crystal-based oscillators that would not be the case, but for musical/analog oscillators I assume these are not crystal derived).

Most analog gear has SOME type of temperature control. Tempco resistors (low resistance change with temperature), thermisters (couple a positive response to a negative response to cancel out) or other techniques (e.g. heaters - get the circuit up to max temp asap and keep it there).

But none of that prevents temperature differences, they just control for them. And you wouldn’t use temp control everywhere - just where it’d effect the sound dramatically i.e. keeping your main voice oscillators in tune, not keeping your cowbell at a precise frequency

This is correct. I have a couple of analog oscillators in my modular rack and the case needs to heat up for a couple of minutes before they generate a stable pitch. Not familiar with the exact reasons to be honest.

The temperature sensitive part in a VCO is actually the exponential converter inside, which has a strong temperature dependence. This is because the current through a transistor depends on the ratio V_BE / V_T, and V_T is proportional to temperature.

It's a neat trick that lets you build good temperature sensors out of transistors, which is very convenient, but in these VCOs you have to add temperature compensation to the exponential converter, and the temperature compensation is far from perfect.

If you take linear VCOs (instead of 1V/octave exponential), they'll be much more temperature stable.

Higher quality equipment that needs a stable timebase will use ovenized oscillators with an integrated heater and a control loop to maintain a stable temperature. These are all inaccurate before they are up to operating temperature.

TVs and CRT monitors were common to change the shape and color of the picture as it got to temp. You never made critical color decisions on a monitor that hadn't been on for at least 15 minutes, preferably 30.

Basically all components have temperature dependent values

The 808 in particular has an additional twist. The transistors used in it were out-of-spec rejected parts as a cost savings measure. So recreations and repairs can have difficulty recapturing the signature sound if they go only by part number.

https://secretlifeofsynthesizers.com/the-strange-heart-of-th...

I’ve owned a few 808s and sampled all of them. They were indeed all different sounding. The cowbells are one exception and sounded more like the 2 Live Crew example. Most of the variation was in the hi hat and cymbals. Which IIRC is 6 square waves and a noise source.

Very interesting! Thank you! I did a little looking and found this FWIW...

I noticed in OP's post that the two frequencies for the cowbell are 540hz and 800hz (although I don't see where this is denoted on the original schematics.) But we'll assume they're accurate numbers.

While a perfect fifth is a difference of 7 semitones, this produces a difference of only 6.804 semitones. It would seem that its designers didn't have a perfect fifth in mind.

Also, 540Hz is C#5 -45 cents and 800Hz is G5 +35 cents. So neither note seems intended to correspond to any natural key.

> While a perfect fifth is a difference of 7 semitones, this produces a difference of only 6.804 semitones. It would seem that its designers didn't have a perfect fifth in mind.

Remember that 7 semitones is not a perfect fifth. (Note this depends on your definition of perfect fifth, some people allow for being close, since equal temperament is so common.)

While a perfect fifth is a 3:2 ratio of frequency, seven semitones isn’t exactly 1.5, it’s more like 1.498.

800/540 is ~ 1.48, so I definitely agree the designers weren’t going for a fifth, very likely they wanted some beat interference to give it a nice metallic warble.

You are correct sir.

I was speaking (a bit erroneously) in the context of an equal tempered scale. (I think.)

Indeed, the natural overtone series is the proper context for a true perfect fifth.

One of the diagrams shows the frequencies as 1.85ms and 1.25ms, 540.5 and 800 Hz respectively.

In the original circuit,the same RC network is used for both the attack and decay so that circuit will indeed produce a 1:1 mark:space ratio.

Curious about the term "1:1 mark:space ratio" since it was also in the article. I would have used the term "50% duty cycle".

I purposely repeated the OP's wording but since we're talking about an astable multivibrator,frequency and duty cycle (in percent) makes sense. I did a lot of circuit design for communications systems and I associate the words mark and space with ones and zeroes in a frame/word.

I wondered if it was an English (not American) phrasing.

More on the origins of the terminology here: https://en.wikipedia.org/wiki/Mark_and_space

The schematic in the article shows trimpots controlling the 2 frequencies, so it was probably adjustable with a screwdriver.

You are right!

4:52

https://youtu.be/rPOqYHMpvqY?t=292

I think yours may be the first HN post linking The 2 Live Crew. And, indeed, Mr. Mixx is way way under appreciated.

Another 808 cowbell recreation and a lot more here: https://www.soundonsound.com/techniques/synthesizing-cowbell....

The whole series is a valuable guide to analog synthesis.

Curious, I had a look ... yep, the SOS series on Roland is still online! (808s in part 2)

https://www.soundonsound.com/music-business/history-roland-p...

https://www.soundonsound.com/people/history-roland-part-2

https://www.soundonsound.com/music-business/history-roland-p...

https://www.soundonsound.com/music-business/history-of-rolan...

It was really interesting to see how someone just used an analog synth to recreate the 808 cowbell. Why not, right? In the other post I made in this thread, I talk about differences in 808 cowbells from song to song and wondered if "manufacturing anomalies in the analog components accounted for this difference."

It's quite possible that some producers weren't using an 808 at all, but rather by using the methods described in your link, created their own specially-tweaked 808 cowbells in order to give it the exact sound they wanted.

I love these deep-dive hardware projects ... best when they are on a small thing like this one (so I'm not too overwhelmed).

Electronics + audio has always been my gateway like programming + graphics (and lighting up an LED is "Hello World").

I don't imagine you could change the pitch of the cowbell on the TR-808, but it sounds a little high pitched to my ear. I guess though that in the era of the TR-808 people were pretty jazzed by electronic percussive instruments that were even close.

I'd argue that the 808 kick drum is the most iconic sound with the cowbell being a close second. I do love that cowbell, though!

I think the kick is most iconic with producers and people into electronic music, but the cowbell is most iconic with the general public.

The cowbell instantly makes me think of Whitney Houston's "I Wanna Dance With Somebody (Who Loves Me)".

https://soundcloud.com/40noisesthatbuiltpop/31-808-cowbell-w...

After hearing the tone, I immediately thought the same thing! Such a great song.

reminds me of old triple six mafia where sometimes it was the main melody, pitched of course

Marcellus Pittman - Chicago Nights

Tube Time took a crack at the 808 including the cowbell last year. https://twitter.com/TubeTimeUS/status/1360734047903707139

Cool project, fun writeup, and more cowbell. Personal pet peeve warning—the components and wiring on the breadboard could use some love. It’s a bit of a mess with the long leads jammed into the board. Clipping the leads down would clean it up a lot.

The CB808 eurorack module from Tiptop Audio is almost a perfect replica I believe: https://tiptopaudio.com/808-2/#cb808

Cool project, but I gotta have more cowbell!

(seriously, thx for posting this - interesting stuff).

Here's the source for that reference: https://vimeo.com/425939085

Shout out to the author for including Dynamix II in the list of iconic users!

"Just Give The DJ A Break!"

always loved this sound. Too bad the obnoxiously caricaturized underground Memphis/phonk revival abused it a bit much.

great article but I would strongly argue the 808 Kick is more distinctive than more cowbell.

More popular sure, but I’m not sure about distinctive. Almost any trap song I listen to has the 808 kick but a cowbell signifies a very specific subgenre/period (or at least and attempt to replicate it) to me.

> a cowbell signifies a very specific subgenre

The TR-909 kick carries this distinction as well as the basis of gabber/hardstyle/etc: BAWHM BAWHM BAWHM BAWHM https://www.youtube.com/watch?v=sLv5x-yduHA

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