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Rave.dj – an artificially intelligent mash-up machine (rave.dj)
199 points by ozzmotik on Aug 27, 2018 | hide | past | favorite | 94 comments

At great risk of sounding haughty, as someone who's perhaps a bit more into the DJing scene than what's probably the average HN user, all of these sound horrible. Beat matching is the easiest part of DJing, and that's about all that this tool does, so I don't think it's solving any DJing problems specifically.

One thing that it does do is take away the turntable GUI (or hardware) and replace it with a two-field upload form, radically reducing the amount of know-how required to perform beat-matching. That's just really scratching the surface of what a lot of "live" DJs do (as they're called these days), as many are bringing instruments like drums and saxophones (see Big Gigantic[1]), keyboards and vocoders (see Lorenz Rhode[2]), their voice (see Gallago[3]), and traditional African drums (see Black Motion[4]), let alone simple song selection and set progression - "reading the crowd".

[1] https://www.youtube.com/watch?v=TkxMjfYOE-g

[2] https://www.youtube.com/watch?v=vwf2uvWlL_c

[3] https://www.youtube.com/watch?v=wmCFPjwlxIU

[4] https://www.youtube.com/watch?v=zHEc9uA2Zmw

When the tool comes along that can style-transfer two songs in the same way that it can for images, then I will admit that AI is on the verge of taking our music-creating/music-playing jobs. But for now, I'm satisfied that there's a bit more to the depth of DJing than that what an AI can learn.

Hey, I'm one of the devs at Rave.

I posted some general responses here: https://news.ycombinator.com/item?id=17852736

We're aiming to make the process as simple as possible, so anyone can make mashups/mixes, and will add on customizations over time. Our focus first and foremost will be to make sure that the core process is solid before we add on to it.

Our AI does do more than beatmatching as well. Though a lot of that is going to be more evident in our mix AI, which we've been focusing on recently.

To be honest I didn't think my comment would get that much attention - and if I did I would've worded it a bit more gently. I think the framework that you've built around this product is really, really, really impressive (the virality and interactivity, for example). But I also think it's a very hard problem that you've set out to tackle. I alluded to it a bit elsewhere in this thread, but there hasn't been nearly as much work put into audio signal learning as there has been photographic signal learning. I'm really excited to see what else can be done, and I'm happy to see that someone is trying to do it. I wish you the best of luck

(But I'm also hoping that this doesn't further dilute the music industry by making music "production" even easier. Pop music is already "algorithmically solved", and other genres aren't as unique as any fan would like to think.)

There are a lot of "mixes" on youtube for electronic music that have great track selection but do simple fades because they don't have the technical skills. If this technology helps them solve that then it would improve my listening experience dramatically.

That is actually precisely what we're aiming to solve! Give those who don't have the technical skills, a means to get the best result they can get, while letting them focus on the part that is important to them: the music selection.

Agreed! I'm in a band called The Wonder Bars[1], and we play house music live with real instruments, but we also include drum machines. We're very far from computers being able to improvise (well), and 4-5 humans playing live instruments is just a crowd-captivating visual. Along with Agent Zero[2], Worldtown Soundsystem[3], and several other bands in the Philadelphia area, we make up a vibrant "live electronic" scene united by the way we make music, not by the genres of music that we particularly choose to write and play.

We're also DJs/producers, and as a DJ, I somewhat disagree with AI ever taking our music-creating jobs. Perhaps playing music will be somewhat more automated in the future, but history shows that creating music will just become more complex and more interesting as we continue forward. Think about it: There are still _professional_ drummers out there, people just paid to drum, when drum machines exist. There are entire orchestras that are paid almost the same salary as developers, yet the Vienna Symphonic Library lets a single person on a keyboard play an entire orchestra's score. The truth is, compositions have classically exploited the modern technology of the day to their own advantage, and I don't see that stopping anytime soon. I can even imagine a world where the independent singer/songwriter suddenly becomes more capable than ever, with AI allowing them to orchestrate entire film scores by just playing a piano or a guitar into their computer. But I don't see the creative aspect of music dying just because we built a machine to organize some stuff better for us.

[1]: https://open.spotify.com/artist/2nrkwnQWEqM20n92QC7Cdy [2]: https://www.facebook.com/agentzeromusic [3]: http://world.town

Oh I definitely agree we have nothing to worry about :) I may have to check you out though! I enjoy live house of many flavors.

But at the same time, photo style transfer is...impressive[1]. It's interesting to me that so many engineers are focused on creating machinery that learns the photographic signal subspace, but there's not too many working on the audio signal subspace.

[1] https://i.stack.imgur.com/Rdoiv.jpg

please take a look at mixes of many songs instead of mashups, that's a lot more relevant to what you are looking for in this product:




They try to only play relevant portions of songs, includes many other DJ rules that Mashups of 2 songs do not.

I'd argue that mixes in their current form could replace a DJ at a small bar patio.

They sound terrible.

It would be pretty trivial to add key-matching to this thing but like you say that wouldn't come close to everything a good dj or live band is doing during a performance with an audience.

This is how well thought out products look like.

- Really simple and intuitive start. I created my first mashup within first 2 minutes and at all times knew exactly what I was doing

- Inbuilt virality. People will show off their produced mixes to their friends and on social media.

- Actually solves a pain point. How many of us have tried mixing songs and gave up? This gives a sense of creativity while taking care of all the complexity.

Even though I don't know how they'll monetize this, it seems a really well thought out product.

Not only that, but the small things like mashing up the song title and album art truly make this a quality product.

Here is my first try: Disclosure - Bang That + The XX - On Hold = Hold That


I tried to give it a challenge, mixing two completely different genres of music – medieval with rap. Amazingly the medieval tune followed the beat of the rap song.


Thanks, that was very enjoyable and I think it would fit right in a world-class DJ mix.

This is definitely the best one in this thread so far.

The mix is pretty awesome!

This is fantastic!

> Even though I don't know how they'll monetize this, it seems a really well thought out product.

Depending on how you define product, this is a major show stopper. I'd say a product can't be called well thought out, if it doesn't have monetization thought out from the start. Although there is always advertizing, I guess..

But very nice tool/toy nonetheless!

All it takes is a pivot at that point.

There are currently 3 major DJ software products - Serato, Rekordbox and Traktor - the ability to quickly throw together a few different tracks into a mashup could be a nice killer feature for one of them to acquire.

Or, playout software for a bar - queue up a load of music of a similar genre and have an automix created.

> There are currently 3 major DJ software products - Serato, Rekordbox and Traktor

There's also MIXXX which is open source:


Indeed - but if you want to be acqui-hired you go for one of the commercial offerings.

As an aside, Mixxx is an awesome piece of software, it's not quite as slick as Serato et al, but it works fantastically if your controller is suitably mapped, and is timecode vinyl agnostic which is a nice plus.

I agree, but two major issues here:

- licensing will be difficult without a paywall, I'm pretty sure this site is "illegal"

- there is no way to keep tweaking manually to correct bad sounding parts etc, which limits usefulness

As it happens I work on a similar iphone app called Pacemaker, which solves both of these problems (using spotify login and a bunch of edit tools, respectively)

Ok. I think I nailed the perfect one: https://rave.dj/ySGzN-0svLlPpA

Wow, I have to say I'm kind of amazed this mashup was generated and not hand-crafted..

Really.. it sounds like someone just hit play on two songs at the same time to me. Beatmatching is trivial.

This one sounds pretty good wow. But Space Jam is hard to mess up to be fair.

I guess the audio mix is good... The video was using 90% of my processing power, what in the world was going on there?

Sounds really good

definitely. bravo.

So I tried to mix two guitar-heavy songs that were bound to be incompatible and the results are kind of okay. Only one has vocals and it comes out way out of tune, but the general development of the songs fits well. It somewhat feels that this has more to do with the predictable sequence of verse/chorus/verse bars in pop music. But eh.

The video is pretty good too:



Edit: Here's an example of an utter failure that illustrates my hypothesis: it mixes a song that has a traditional verse/chorus/verse structure with a techno track that's a monotonic crescendo. The algorithm doesn't know what to do about it (the correct answer, although not leading to great music, would be to use parts from the begginning of the crescendo track so not to overpower the pop song.)


Edit 2: Here's an easy one it gets wrong: track 1 has great loopable instrumental grooves that go on each for a few bars before rap vocals kick in. Track 2 is a person talking. It should not be overlapping vocals, it should just highlight the instrumental loops.


I think the tracks needs to carefully picked by a human first, then it can turn out good. Too many chords and melodies in both tracks just creates a mess. Pure drum and beat tracks on top of melodies seems to be an easy combo:

Covers on top of the original was a surprising success:



Pure drum tracks plus acapella:


But dissonant melodies can sound good; for a while bitonalism (some Debussy; most notoriously Darius Milhaud) was a compromise or a gateway drug to straight atonalism. My first example has vocals in a different key from the guitar, but the song structure works.

Basically mixing any pop songs work -- here's a very very very good one with Sepultura + Pet Shop Boys


... the point being that pop music is very very regular in its verse/chorus/verse narrative curve.

If there's any Eurovision geeks here, I tried putting two Eurovision songs together, and now I can't stop watching "I Feed You My Rhythm Inside" by Margaret Berger vs Loïc Nottet. I must have played this 10 times in a row now.


After watching this, I want to watch another, similar mashup. This site could really use a recommendation/autoplay system, and I could listen for hours. Maybe I've been watching Youtube too much.

This is probably the best one I've seen because it gets the phrasing just right

As long as there's a pretty predictable 4/4 beat, it seems to do well.


DJ AssultPink - Ass ' n ' TT

Although the BPM detection usually works, It seems to have trouble getting the songs synced in phrase - 2nd tracks come in starting on the 3rd bar or something.

If there is someone here who also played Donkey Kong Country 2 in his/her childhood: Some of its tunes make for a pretty decent hip hop beat.


That blur filter absolutely annihilates my macbook's CPU.

EDIT: 4 hours remaining... hmmm.. feeding it a 400 track playlist probably wasn't a good idea

Tried to use some generic pop songs ( https://rave.dj/BtHuRn1-lAnDEQ - [madonna - hung up] & [ timbaland - the way i are ]) and result is not bad at all, a bit cacophonous in some parts, but other than that it's [the smashup] quite good!

Interesting mashup -


I tested - Run DMC - It's like that vs Funky Town.

Run DMC vs. Toni Basil - 'Hey Trickey' did not turn out as good as I'd hoped:


A few Raves I did that I like (most are with It's Everyday Bro because rave.dj tends to work well with that song):




https://rave.dj/U4BPJ9duII-o9Q (gets off-sync later sadly)


None of these are perfect but Rave is A LOT of fun to mess around with, there's no denying that.

I think you'd probably like making a mix too! https://www.rave.dj/iOfKQXFw3TxTWA

Just provide ~50 or more songs for best results

I've done it before, those are a lot of fun too.

Any blog posts on how this is working?

Michael Jackson, Janet Jackson & The Wurzels...

Scream Harvester: https://rave.dj/talVuJvYAn6zbA

Seems to just be a beat matcher / BPM adjuster, which is interesting in itself, but quite basic features in any DAW/DJing software.

combine harvester intensifies

It produces some quite funky technical death metal too.


This one is great! My grindcore experiment wans't too successful, but it gave me a chuckle anyway.

Nasum & Napalm Death: Face the Children

[0]: https://rave.dj/yjDMS4Pu0a81ZA (Napalm Death: Suffer the Children vs. Nasum: The Masked Face)

Seems to be pretty awesome. I tested out two instrumental bits in Hardwell - Spaceman and SHM - Greyhound and found that the algorithm had some issues with the low end clashing on mixing between the songs https://rave.dj/qP-eYlelx75GjQ Though it leveled out after a few seconds. Would love to know more about how it works!

Definitely. I'm so curious.

Rammstein Vs. Crazy Town. Dark :-)

Du By The Hast https://rave.dj/sN4EnkKdPfj-ow

Just one side note, that moving background is giving me motion sickness :) But I am gonna probably spend a lot of time, making mixes...

Yes, this background video makes for a terrible experience. I know it looks cool and startupy (at least it did in 2015) but this trend has to stop.

Ended up hiding it with an ad blocker rule.

Hey all! I'm one of the devs at Rave (working on the website). This is really cool to see all this interest in us!

To address a few points I've seen on here: We do more than just beatmatching. That said, most of our recent technical advancements are done on our mix AI, as it's been our recent push. Give mixes a try (which work better the more songs you give them)! We'll be pivoting back to mashups soon as well to continue improvements on that AI, particularly rolling in some of the improvements we developed through the mix AI.

Our goals have really been to bring mashups and mixes to those who don't have the technical ability first and foremost, and focus on making it as accessible as possible. We want to make sure our baseline is solid before targeting customizations. I feel paraschopra's post really captured what we wanted to achieve.

Ultimately, we're still at the beginning of what we want to do, and have plenty of improvements on the way.

Some feedback:

* Awesome job, here are some feature suggestions:

* The ability to rate the mix/mashup as the author

* The ability to rate as an audience

* visual of the algo's understanding of the songs sound profile and how its lining them up

* The ability to select the time-range of the song which must be included/excluded from the mix

* ability to ask it to weight a repeating frequency of a song

* name of the artist/track/video playing displayed


Where are you guys located?

Good suggestions, we're located in Kitchener Ontario Canada.

RE: "ability to ask it to weight a repeating frequency of a song" - you'd want songs to appear in your mix more than once?

Yes, if I am mixing a series of my favorite songs... also I may want it to mix from A B C B A B C A to see how that sounds...

Pretty interesting. I used to be heavily into the mashup scene, even going so far as to make mashup.fm (another turntable/plug.dj clone). Here's some of my favorite classical mashups alongside the rave.dj version:

Thomas the Tank Engine vs Biggie Smalls

Original: https://www.youtube.com/watch?v=ETfiUYij5UE

Rave.dj: https://rave.dj/XUBqv8IsZPVZMQ

This was the easiest as it's just a vocal track laid onto a beat, but it really jumps the tracks around a ton, seemingly randomly. It at least doesn't jump mid-measure though and fits with the beat.


Modest Mouth (Modest Mouse vs Smashmouth)

Original: https://www.youtube.com/watch?v=wEmJH7JsKgM

Rave.dj: https://rave.dj/gUb_lU_PrHBdKA

The Neil C original is a classic, and really fits two songs together that don't belong near each other. Rave plays the intros in sequential order, with vocals overlapping all over. They really need a central channel filter to see if they can pop the vocals out from the instrumentals. This is really a tuesday-surprise lunchroom casserole of a mashup, with a rather abrupt ending.


Korn vs Taylor Swift

Original: https://soundcloud.com/user-490703809/we-are-coming-undone-k...

Rave.dj: https://rave.dj/usdGtcmoNJeItg

This one really works because of some of the more complex editing on Isosine's part. The rave one is a disaster. Feels like you're standing in between two parties that are blasting two jams, that just happened to have their drops/choruses line up.


Kanye West vs The Beatles

Original: http://mashup.fm/media/Hey_Jude_We_Major_More_Popular_than_J...

Rave.dj: https://rave.dj/ZcRpPLK6QZEvZA

This is a personal favorite, and I think it works because of how long the Hey Jude intro is. It really means you forget about Kanye completely until he jumps in. It works because of how slow of a buildup Hey Jude is. The Rave version has no nuance here. They speed up Hey Jude, up-pitching it in the process and making it sound like Raffi or some other child entertainer. They down pitch Kanye, making him seem like some gangsta thug. It really doesn't work at all.


I really want this to become better, but I feel like it needs to be trained more tricks (vocal separation for one) to really be worth it. Also minor QOL improvement would be to allow you to preview tracks before you add them to the mix. Hard to find one that's a good audio only rip of a song sometimes.

Enya vs. The prodigy

Original: https://www.youtube.com/watch?v=5knIIyKpSK4

Rave.dj: https://rave.dj/moZFRBY95T53zA

Very pleased with the result.

Love it!

What I find very interesting is, the stability of the system. There must be quite the heavy load on the machine: retrieval, analysis, tempo matching, mashup creation, encoding and all on a ~11 hours HN-related stress test.

Acoustic Blues - Spotify playlist via rave.dj: https://rave.dj/NX2BLIeTJW_YtQ

Was better than I expected, this is kind of a stress test

Pressure Jean https://rave.dj/23kYqXObZm0izg Billy Jean and Under Pressure... what a lovely site.

This one managed to match up the lyrics of two similarly-themed songs surprisingly well, assumedly by accident: https://rave.dj/y0GOaTZwBsEvYw. "But mighty fine only got you somewhere half the time, the other half either got you... eighteen years, and on the eighteenth birthday he found out it wasn't his!"

And a surprisingly successful merger of Cutty Ranks and Abba with the awesome title of "Limb Queen"


I giggled all the way through it. A bit of better volume balancing where the two songs overlap and I'd play that at a party with no regrets...

nice - as you say, would be better if the Abba track was lower in the mix when it first comes in, but the timing and parts used to bring it in are spot on.

Perhaps the algorithm would do better with better quality versions of the track rather than youtube quality?

Awesome project! I just made https://rave.dj/0GU6N96tgPXj9Q and it's awesome! love being able to use a Spotify playlist.

Have you considered using BunnyCDN instead of Stackpath for the CDN? It'll probably be much cheaper.

Wow, it actually produced something kind of reasonable for the least reasonable input I could come up with. I present "In the Hall of the Dracula Mountain King" https://rave.dj/1jK2s4-jAt3meg

Ironically, this seems to really struggle to make good mixes from techno. It mashes it up a bit too much.

You could say that for this one as well, but its still pretty impressive https://rave.dj/sVAYFGYFUxM2nw

Use case recommendation: pick a track with a good background beat and another track that is mostly lyrical to lay over it. ie: https://rave.dj/XDTIdjbTSIWHxw (gets great at 30 seconds)

I played with it and used some generic party songs. The result is not bad. This one for example, "Hey ya! on steroids"


Holy crap, Dolly Parton vs Richie Hawtin. It's much much better than expected but not quite ready for the dancefloor yet.


周杰伦 meets 3 Inches of Blood: what the world really needs is more bilingual songs about slaying the orcs! https://rave.dj/aO7XPBNgFR7W_g

Check out mixes of many songs, they include many more advanced techniques than seen in mashups: https://www.rave.dj/iOfKQXFw3TxTWA

Seems like you can put rap with anything and it'll sound good!

Here's the Killers with Eminem: https://rave.dj/3OYTG3uFFUrMIg

Cat music mashup. Guaranteed to make your cat look at you as if you’re an idiot. https://rave.dj/PKqlwGPNObCcaw

My first two attempts didn't turn out that great. However, N.W.A + Beatles works!


Turn Down for What seems to go well with a lot of songs: https://rave.dj/cBQ8koXg_09blA

Because it's one of the rare electronic songs that became popular whose speed is ~100 BPM (BPM = beats per minute in this case). That makes it compatible with a lot of pop and hip hop songs. Add to that the fact that it contains almost no lyrics (while pop songs contain almost no low frequencies) and you have a match.

As expected, French House mixes very well ;-)

Daft Punk + Justice: https://rave.dj/Lpr1oWauUIIeaA

Tu traines sur HN toi ? :)


that was actually heaps better than I expected.. https://rave.dj/q9LAsKpPBKVPhw

Blondie (Rapture) and The Beastie Boys (Fight for your Right)


Love the UI and UX and the idea, but unfortunately the end result was impossible to listen to. Might've been just me picking 2 incompatible songs.

Little L x Boogie Nights https://rave.dj/G1X1uN36e977Hw

Useless. All the prog house tracks I would actually want to mix with a tool like this are around 9 minutes, which is "too long".

Does the "Mix many songs into a DJ set" option even work? It seems to create a mashup instead.

Try adding more than two songs, ideally 50 or more to give the AI something to work with. I'd recommend picking a YouTube playlist.

Doesn't work for me - I get short glitchy bursts of noise and then it stops.

Chrome 68.0.3440.106 on an iMac Pro.

Can you hop onto the discord server so we can help you.

Actually that was caused by a rogue FB tab eating 100% CPU. [Sigh...]

All fine now.

The two best results I got (both were 'easy' for the AI, but I was still surprised):

Supa Hot Fire + Linkin Park: https://rave.dj/Kph8bLPfCCmsaw

A known bass drop + Sia - Chandelier: https://rave.dj/h9rjxodw1vjgkw

What's with the high CPU usage?

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