The interesting (to me anyways) thing here is that there's nothing illegal or wrong building an emulator, you're just mimicking a chip and translating instructions. Building an UI is not wrong either on the same grounds. But the issues begin with providing access to ROMs (which to be fair DiscoDSP doesn't do... I think), and the legal problems begin with the ROMs. As they're the ones profiting from a system that requires the ROMs which they do point to you could say they're opening themselves to legal problems.

Putting out an emulator by itself as mentioned is not illegal, but explicitly selling access to sounds provided by the ROMs might be. Maybe synth companies are not rich and well endowed in the legal department or might not even care, but it's a risk DiscoDSP has taken.

 

Halllo @Will Kweks, it's not a lawless space, and companies aren't stupid; no one exposes themselves to lawsuits they might lose and that could ruin their business. Please read the following from The Usual Suspect on the KVE website:

DSP56300 Emulator is an open source project to emulate hardware synthesizers that use(d) the Motorola DSP56300 series of DSPs.

The initially available Osirus plugin emulates the Access Virus B & C.

Please note that the download includes ONLY the DSP Emulator as ROMs cannot be included due to copyright reasons.

Please pay attention to the following FAQs:

Isn't it illegal what you are doing?

A: The emulation itself is not illegal. Sharing of the hardware ROMs is illegal though. What this means is that a user will need to provide the ROM file of a synthesizer that it wants to emulate. It works similar to game console emulators, where the emulator itself cannot execute any game until you provide a ROM of it.

Where do I find the ROMs needed to run the emulator?

A: We neither provide ROMs nor do we guide you to find them, as distribution of copyrighted material is illegal and this is not our intention. Please refrain from asking about ROMs on our Discord server.

Source: www.kvraudio.com/product/dsp56300-emulator-by-the-usual-suspects

 

I was talking about DiscoDSP, not The Usual Suspects. I do think TUS is safe here, thankfully.

As I said: making an open-source emulator is not illegal, but selling one (with a nod to ROMs, unlike TUS' one) is a legal grey area. I refer to Nintendo again which has shut down several projects with less so there's legal precedent depending on where any possible legal action might take place.

I think this is unlikely though as synth businesses either don't care or don't have the legal firepower to fight this for little gain. But would you trust to buy into a product that might or might not continue working?

 

To put it another way, the original question was whether it's permissible to simply clone the chips built into NordLead, for example, and why NordLead allows software cloning. You should ask and answer that question. Imagine if NordLead sued The Usual Suspect. Or did you hear that they had permission? It's a legal gray area, in one opinion.

Because the basic concept belongs to NordLead; they even have a patent on their synthesizer.
Now, The Usual Suspect is purely software-based, and if you own a hardware NordLead, you can play the ROM in the soft emulation.
The fact that there were no lawsuits is due to the clever programmer of discoDSP discovering and exploiting this market gap. He's doing a little advertising for The Usual Suspect 2 and might even earn a few euros in compensation, depending on the users' goodwill!

The Usual Suspect 2 Perhaps we should ask the manufacturers for a statement. I can easily imagine some saying, "So what?" and others finding it unacceptable. Anyone performing live as a musician will certainly buy an original Nord Lead.

As you know, discoDSP already offers a Nord Lead clone in their Discovery Pro lineup! It includes Nord Lead 2 SysEx import and export, enabling seamless integration with existing sounds. www.kvraudio.com/product/discovery-pro-by-discodsp

 

From a purely legal standpoint, the developers could sue the sister site because it offers the illegal ROMs for download.

Isn't it illegal what you are doing?

A: The emulation itself is not illegal. Sharing of the hardware ROMs is illegal though. What this means is that a user will need to provide the ROM file of a synthesizer that it wants to emulate. It works similar to game console emulators, where the emulator itself cannot execute any game until you provide a ROM of it. Source: www.kvraudio.com/product/dsp56300-emulator-by-the-usual-suspects

 

We're going in circles, so I'm going to stop after this. But these are facts: emulation is legal, cleanroom implementations are legal, and there are plenty of court cases proving this. This not under dispute and this is what TUS is doing so they're in the clear. What DiscoDSP doing could be interpreted (see the linked Nintendo case above) interpreted as circumvention, as they're selling a product that needs somebody elses copyrighted code to function. Profiting from copyright infringement is a big no-no, again seen in many big cases against torrent site operators and such.

As for their Discovery synth (which I've bought way back when, it's good) it contains (well, hopefully) no copyrighted code so it's a cleanroom implementation, and as of such OK as long as they don't use any trademarks there (like original Nord graphics and such).

 

Retromulator – Great Synth Bundle or Open-Source Controversy?

 

Nobody gives a flying fuck about Disco DSP.
Whoever buys a 199$ Nord Lead VST instead of Serum 2 in 2026 is an idiot.

Get the Usual Suspects DSP56300 releases.
Donate if you can, if not say thanks.

Bye <3

 

Honestly, I think this is a bit of a nothing-burger.

Who's going to use this? Preset surfers need the ROMs in any case, and if they're savvy enough to find those, they'll end up coming across and probably wanting to use the TUS versions instead.

Even if someone managed to find the ROMs but somehow remain unaware of TUS, anyone they tell about Retromulator will in turn point them at TUS ("yeah, those are the big boy plugins").

If they want to create their own patches, this is a non-starter. So there's no word of mouth or glory for discoDSP to be had here.

Website also clearly states where the underlying technology comes from.

I can't imagine Retromulator ending up stealing much, if any, thunder, glory or donations from TUS.

Might end up being a Streisand-effect plugin, boosting TUS' exposure, shrug.

I say this because I wasn't aware of the DX7 emulation bundled with Retromulator before, and now it's become my favourite DX7 emulation.

 

discoDSP is releasing a plugin that doesn't produce a single sound, because the ROMs are illegal!!! Seriously?

 

Last edited: Mar 9, 2026 at 4:00 PM

This is part of marketing; it's about attracting people and future customers. This kind of thing draws people to the website and gets them talking about it again. Production costs were low, and the expenses for the plugin were below the advertising budget.