About USB Noise - clevelandmusicco/HothouseExamples GitHub Wiki

[!NOTE] What follows is the response to a user on a forum citing "faint fax machine noises" and "rhythmic popping and clicking" when using the Hothouse.

This is a fairly common issue, and it often comes down to quality of power in conjunction with a USB connection. What follows isn't just me mansplaining to the OP; it's for anyone who experiences this issue for the first time :metal:

The TL;DR might be this: When you're using the Hothouse to make music and you don't need the USB cable plugged in, unplug it. This was the originally intended use case. However, we're seeing folks cleverly using the Hothouse as a USB synth, which clearly requires the USB cable. Still others just don't want to be bothered with ever unplugging the Hothouse from their computer. Fair dos! So, what's the root cause of the noise and how can we fix it?

One likely culprit is ground loop interference. A ground loop happens when multiple devices share the same ground (for example, through USB or audio cables), but slight differences in the ground voltage between them cause unwanted current to flow, usually presenting as humming or buzzing in the audio signal. In some cases, this can also result in faint ticking or clicking. Devices powered by USB are especially susceptible to this.

To fix it, some people swear by anti-ground loop adapters. For example, Arturia famously includes one with its Keystep 37 and BeatStep Pro products. While I haven't used such adapters myself, I've read claims they are effective.

However, what the OP described in the forum post sounds more like USB power noise and interference caused by USB bus activity. The USB cable from your computer supplies 5V directly to the Daisy Seed, but USB power from a computer can be "dirty," meaning it can carry EMI or switching noise from internal computer components. The constant USB polling and data exchange can also cause disruptions, which leads to power fluctuations that might be heard as noise.

A common solution for this type of issue is to use a USB Isolator. Again, I don't want to shill for any specific product; folks should research and make their own decision.

Having said all that, here are some general suggestions for integrating audio, computer, and USB-powered kit:

• Invest in a good power conditioner for your computer, audio interface, and any outboard gear. Poor-quality power from the mains supply can introduce noise that downstream devices don't always effectively filter out. Start with clean power to the overall system.
• Use a high-quality, truly-isolated power supply for effect pedals (including the Hothouse). Cheap, poorly regulated power supplies can cause a lot of noise. And beware many products marked as "isolated", but simply are not. I personally use the Strymon Ojai, but there are lots of options available.
• Use shielded USB cables with ferrite beads where it makes sense. This can help block out EMI and further reduce the chances of noise.
• Keep your cell phone on the other side of the room :wink: (I suspect everyone knows this, but just in case ...)
• And ... IF ... you still have issues, use a high-quality USB isolator. I have the Intona USB 2.0 Hi-Speed Isolator, and I have to use it when working on my development computer (which is decidedly NOT an audio setup). But when plugging the Hothouse directly into my DAW system through an audio interface, I don't need an isolator at all (not even with the USB cable plugged in).

As with most technically complex things, your mileage may vary. There are so many variables specific to each person's setup, that it is impossible to diagnose and resolve all issues with a wiki page. But if just one person finds this useful, it was worth posting here.