The Yamaha DX21

The Yamaha DX-21 is a 61-key synth, based on FM synthesis, from the mid 80s.

It is 8-voice polyphonic, and while it sounds very close to other DX’s, it was a consumer keyboard, without velocity or aftertouch sensitivity.

If you’ve used the Yamaha DX21, leave a comment with your thoughts on it!

Features:

  • Performance Memory – 32 Performance Memory System, programmable with data on play modes, key shift, detune and pitch bend. It will automatically recall these real-time performance parameters as well as the voice or combination of voices.
  • FM Digital Synthesis – Instead of VCOs, VCAs, and VCFs, the DX21 uses “operators” (a digital sine wave generator combined with an envelope generator) to produce sound that can be used alone or in combination with other operators.
  • Voice Memories – 32MB RAM (Random Access Memory) voice memories, organized in two banks of 16 voice selector keys.
  • Pre-Programmed Voices Built In – 128 pre-programmed voices permanently stored in internal ROM (Read Only) memory. Organized into groups of 8, these voices can be loaded individually or in groups into the 32-voice RAM memory.
  • Three Ways to Play – Two FM Tone Generators allow voices to be selected three ways: Single, Dual, or Split play modes.
  • MIDI Functions – A broad range of MIDI functions make the DX21 exceptionally useful in virtually any MIDI system application.
  • Cassette Storage – A built in cassette interface allows an unlimited number of voices to be programmed and stored on cassette tape. Cassette voices can then be loaded into RAM memory when needed.

Specifications:

  • Keyboard 61 keys, C1 – C6
  • Sound Source FM Tone Generators: 4 operators x 2 (A,B), 8 Algorithms
  • Polyphonic 8 notes (Single), 4 notes (Dual), 4 + 4 notes (Split)
  • Monophonic 1 note (Single, Dual), 1 + 1 note (Split)
  • Internal Memory 128 ROM voice memory, 32 RAM voice memory, 32 RAM performance memory
  • Controls Pitch Bend Wheel, Modulation Wheel, Volume, Balance, Data Entry
  • Displays LCD (16 characters x 2 lines)
  • Connecting Terminals Output Mix/A, Output B, Phones, Cassette
  • Control Terminals Footswitch (Sustain, Portamento), Foot Controller (Volume), MIDI (In, Out, Thru)
  • Dimensions 909(w) x 82(h) x 270(d) mm, 35.8(w) x 3.2(h) x 10.6(d) inches
  • Weight 8 kg (17.6 lbs)
  • United States and Canada 120 V, 50/60 Hz
  • General Models 220 – 240 V, 50 Hz
  • Power Consumption 7 W

Resources:

16 thoughts on “The Yamaha DX21

  1. The DX-21 was my first synth (together with the D-110). Never used it much, sold it 2 years ago, got it back some months ago. It has some funny digital artifacts on low pitches. Besides this – hard to program, gets boring quite fast, not too interesting sounds. Still looking for a FS1R 🙂

  2. This was my entry into synths. I had a saturday job when I was about 15 and saved up all year to buy a DX keyboard. I didn't have the money for the DX7 which I realy wanted. I remember on Christmas eve my dad picking it up from the music shop for me. I also got a Peavey KB15 amp.
    The sounds are very…….FM if that makes sence. Some realy nasty stuff but at the time it was magic!!!!!
    I sold it at the begining of the 90's and relpaced it with a Roland U20.
    I recently got hold of a second hand DX11 which is like four DX21s put together with touch keyboard and easy edit. It is great.
    Oh yes, the good old days when synths had personalitys and not just a box of GM sounds.

  3. I bought a DX21 a few years ago. I was looking for something that sounded very digital in contrast to my analog synths. I couldn't afford a DX-7 or 200 so I got this one. I can't agree with the guys above. This synth has some great sounds in it. There are more presets than the 32 that are loaded at start-up. There are some good basses, leads, strings and other jewels in there. The split and dual functions are great. It also has stereo out and a chorus. I've gotten some very strange, beautiful and glitched out sounds from this machine. It takes some time to get used to, but is worth understanding and digging deeper.
    My only complaint is the terrible MIDI implementation. The MIDI buffer fills up too easy if you send it too much really fast. And don't try to record midi out because although the synth is velocity sensitive the keyboard is not. It also sends out a constantly varying volume signal over midi. So all that gets recorded recorded with the notes unless you filter them.
    So just slave it to your master midi keyboard and your fine. Or just get a DX-200 or FM-8
    I just don't think some of these guys got into this machine enough. Probably were disappointed that it didn't sound like a Moog or something.

  4. My buddy randomly acquired one of these synths (I think some stoned musician left it at his place…) and after looking at it sitting in the corner numerous times, we plugged it in and started messing with it. My first impressions of it were absolutely terrible. The native patches were basically useless, and the interface seems to be designed to be as counter-intuitive as possible. I would agree that the sound was thin and brittle; it had no life. We didn't use it again for around six months until one day the we got a copy of the manual and found out how to actually work the thing… We were jamming and I decided to run it through my guitar effects rig and a Fender Blues Junior. Immediately the sound was fuller, warmer, and entirely more delicious. It took a long time to realize, but running this baby with the right rig can give you an incredibly bad-ass sound. I favor the electric piano and organ patches; this guy has become all I need for a sweet stage rig! If you have one I highly recommend running it through compression, delay, chorus (although it does have a sweet on-board chorus), auto-filter, and overdrive, ending in a moderately powered tube amp. You will be impressed… This board has become a part of my sound, and I find great pleasure in playing it.

  5. This was my first synth. It was a chip off the old dx7 (half the operators in FM land). but cheaper.
    Lots of thin stock sounds but clean. I ripped on mine by adding a guitar wah pedal and radioshack delay box. If you learned how to layer and detune it turned into a thick monster synth even if it had limited polyphony. I saw one at the local music store years after I traded mine… I remembered how to access the custom voice library (pressing two buttons at once) and sure enough this was my old synth with my custom voices! the guy at the music store did not believe me when i told him i bought it new when it first came out in like 86. I miss my POWER SYNTH days….killer organ sound as well….

  6. Okay, This is how you get "good synth" sounds out of a FM synth. It has several simple sine waves that can modulate one another right? Modulating the other sine waves creates more complex wave forms like a saw or even noise. And if you use a low pass filter on a square or saw wave on a subtractive synth (like a Moog etc.) you basically get a sine wave right? So all you need to do is set the volume control of the operator/sinewave that's doing the modulating to the edit slider and move it up and down to get filter sweep sounds. And you're on your way to creating fat sounds with a FM synth 😉

  7. Okay, This is how you get "good synth" sounds out of a FM synth. It has several simple sine waves that can modulate one another right? Modulating the other sine waves creates more complex wave forms like a saw or even noise. And if you use a low pass filter on a square or saw wave on a subtractive synth (like a Moog etc.) you basically get a sine wave right? So all you need to do is set the volume control of the operator/sinewave that's doing the modulating to the edit slider and move it up and down to get filter sweep sounds. And you're on your way to creating fat sounds with a FM synth 😉

  8. Okay, This is how you get "good synth" sounds out of a FM synth. It has several simple sine waves that can modulate one another right? Modulating the other sine waves creates more complex wave forms like a saw or even noise. And if you use a low pass filter on a square or saw wave on a subtractive synth (like a Moog etc.) you basically get a sine wave right? So all you need to do is set the volume control of the operator/sinewave that's doing the modulating to the edit slider and move it up and down to get filter sweep sounds. And you're on your way to creating fat sounds with a FM synth 😉

  9. Okay, This is how you get "good synth" sounds out of a FM synth. It has several simple sine waves that can modulate one another right? Modulating the other sine waves creates more complex wave forms like a saw or even noise. And if you use a low pass filter on a square or saw wave on a subtractive synth (like a Moog etc.) you basically get a sine wave right? So all you need to do is set the volume control of the operator/sinewave that's doing the modulating to the edit slider and move it up and down to get filter sweep sounds. And you're on your way to creating fat sounds with a FM synth 😉

  10. Okay, This is how you get "good synth" sounds out of a FM synth. It has several simple sine waves that can modulate one another right? Modulating the other sine waves creates more complex wave forms like a saw or even noise. And if you use a low pass filter on a square or saw wave on a subtractive synth (like a Moog etc.) you basically get a sine wave right? So all you need to do is set the volume control of the operator/sinewave that's doing the modulating to the edit slider and move it up and down to get filter sweep sounds. And you're on your way to creating fat sounds with a FM synth 😉

  11. Okay, This is how you get "good synth" sounds out of a FM synth. It has several simple sine waves that can modulate one another right? Modulating the other sine waves creates more complex wave forms like a saw or even noise. And if you use a low pass filter on a square or saw wave on a subtractive synth (like a Moog etc.) you basically get a sine wave right? So all you need to do is set the volume control of the operator/sinewave that's doing the modulating to the edit slider and move it up and down to get filter sweep sounds. And you're on your way to creating fat sounds with a FM synth 😉

  12. I use a DX 21 for my left hand bass playing. I have it set at trumpet with it brought down an octave. Not crazy about the bass presets so I use the trumpet preset brought down an octave. This makes the Yamaha DX 21 sound like the Farfisa bass section or the Rheem Kee Bass keyboard. I have had 5 DX 21's in the past 20 years and will continue using it.

  13. While it’s true that the DX21 had its shortcomings, such as lack of keyboard velocity and pressure sensitivity, it was a good, misunderstood keyboard. I had it in a setup along a Roland JX-8P, where I could command sounds (and use the keyboard’s own only for solid, leveled leads or counterlines) via a Digital Music Corp. MX-8 patchbay (at my feet via an increase-decrease pedal). Additional sounds were exerted from other sound modules such as a Kawai K1r and a Yamaha TQ-5 (which was, by the way, compatible and could exchange sounds from the DX) and sounded incredibly dense if edited. True, you needed a deeper understanding of FM technology and a little tweaking to obtain sounds, but I actually felt a keyboard god of sorts using it in mono mode with Key-On portamento to summon ELP-like solos. Just think having its saxophone sound with K-OP and a little deviation on the modulation to obtain a solid, blistering solo, able to compete with a thick stacked analog sinth sound anytime. It was also the balance to my electric piano setup, where the JX would do the bass to mid part and the DX would take on from mid to high notes in a fake-stereo image thanks to manipulating keyboard scaling. Very misunderstood indeed.

  14. I had all of my equipment stolen on Christmas eve in 1985 and had little money at the time so I bought one of these gems to gig with. I added a few outboard effects to make it sound richer. The electric piano patches and the organ patches were awesome and I was able to produce some screamer leads. It got me along until I was able to add a tx81z, DSW-8000 and arp odyssey back into my live rig. I midied to the TX to double the sound. I rounded out the end of the 1980;s still using that equipment and an additional ARP 2600 in my live rig. I loved the sounds, just had to add outboard processing, delay, overdrive, etc from guitar pedals and rack effects to get what I wanted. This thing is still in my home studio and still works, so does the tx81. I still program them from time to time to get weird percussive stuff.

  15. More usable and fun (to me) than the DX7. Sold my DX7, kept my DX21. Thinking about trying a DX11 one day.

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