Herbs and Stones Solid Felt review

We get to know this “clever” standalone filter device

  • £499
  • $499
Herbs and Stones Solid Felt
(Image: © Future)

MusicRadar Verdict

A fantastic filter, in both sound and usability. Nicely constructed and compatible with everything from a dynamic mic to Eurorack


  • +

    Lots of versatility.

  • +


  • +

    Stereo and mono patching potential.


  • -

    No resonance CV.

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Herbs and Stones Solid Felt: What is it?

Like its own Liquid Foam, Herbs and Stone’s Solid Felt comes in a sturdy desktop case making it an ideal standalone filter device. 

While some Eurorack users will bemoan that they can’t mount it in their rig, we wouldn’t be surprised if a Eurorack version appears down the road. 

As it stands, the versatility offered in this format is worth it, as it makes it far easier to patch keyboard synths, guitars or even patch software signals into it.

Solid Felt is, on the face of it, quite a simple, unassuming device but don’t be fooled. This is one clever little box of tricks. Not only can it be controlled manually but also via the 16 CV patch points (Eurorack-compatible) making automation a breeze should it be required. 

That said, Solid Felt has the means to create evolving modulated patches built in with its LFOs that can be set to control a variety of attributes.

Herbs and Stones Solid Felt

(Image credit: Future)

Herbs and Stones Solid Felt: Performance and verdict

Solid Felt is stereo and can operate in a variety of ways. It can take a mono signal and morph it so that filter sweeps can pan across the stereo field. Or it can be used as a fuzzy drive, adding lovely warm saturation to more sterile audio, perfect for processing software or digital synths. 

The stereo option can be switched to a mono one, with the payback being a serial filter signal at 24 dB.

A novel feature is CV morphing of mode. Seeing as the filter is multimode (with low pass, high pass, and bandpass) this really opens up some potentially unique possibilities. 

This works a treat and should be seriously considered in the place of filters you may have in synths, as it is rare to find and can produce some truly unique results. 

Solid Felt also converts line input signals to Eurorack level, making it a great way of getting less common signals into your patches. Guitars, basses, and other instruments are rarely filtered like synths, but Solid Felt makes it easy to generate some interesting new timbres, making this somewhat of an experimenter’s dream.

To touch more on automation, the LFOs are very useful and also offer some features not often seen, including dual outputs at 180 degrees phase as well as CV control over the shape (triangle to square on one, sawtooth on the other). 

Most aspects can be CV controlled, although not resonance which is a shame. That said, the sheer amount of control on offer here is more than respectable and should please the keenest patchers out there.

Herbs and Stones Solid Felt

(Image credit: Future)

Jack of all trades

There’s a lot to like with Solid Felt. It serves many purposes and does so well with a shallow learning curve and a great opportunity for sound design. For example, you can bypass the filters with the press of a button but keep control of the gain. 

Useful for a little fuzz or to prevent the signal from dropping when not filtering. This attention to use cases and musicality shines through all over the device.

MusicRadar verdict: A fantastic filter, in both sound and usability. Nicely constructed and compatible with everything from a dynamic mic to Eurorack.

Herbs and Stones Solid Felt: Hands-on demos

Gianluca Herbertson

Herbs and Stones Solid Felt: Specifications

  • KEY FEATURES: Analogue multimode filters, 8x 1/8-jack Eurorack-compatible CV inputs and outputs, A voltage-controlled LFO with waveform blend control and two outputs 180° out of phase, Mode control to select between low-pass, band-pass and high-pass filter response (CV controllable).
  • CONTACT: Herbs and Stones