Disclosure: I’d like to thank Linsoul for sending me the Twistura Sigma for this review. All thoughts and opinions are my own, and Linsoul had no say or input for the contents of this review. Info and purchase links for the Twistura Sigma are at the end of the review.

The Twistura Sigma is a bullet-style IEM with a hybrid driver configuration, featuring a 6mm DD (dynamic driver) and a BA (balanced armature) driver. It’s currently being sold for $79 USD and is said to offer a smooth and balanced sound signature with natural tones and clear audio. Let’s get into it and see what the Sigma is all about.

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• Twistura Sigma IEM
• Two sets of S, M, L ear tips
• Silver-plated copper cable with 3.5mm termination
• 30-ohm Impedance adapter
• 3.5mm to USB-C dongle DAC
• Leather case with clasp

For a $79 USD IEM you get a good amount of accessories. Looking first at the packaging and unboxing experience, Twistura did a good job fitting everything into a slim and small-ish box.

The included ear tips seem to be of good quality, and the two sets differ in height, allowing for either a deeper or shallower insertion depth into your ear.

The USB-C dongle DAC is a nice inclusion and ensures that you will have adequate power and volume to give the Sigma. It supports up to 32-bit/384kHz sample rate and performs well in my testing.

An impedance adapter is also included, which is typically used with sensitive IEMs to reduce the noise floor, ensuring clean and noise-free audio.  Never had that issue when using the Sigma without the adapter as it’s not a particularly sensitive IEM, but it did help when using the Sigma with my iFi ZEN DAC V2. This is because powerful desktop DAC/Amps can sometimes provide too much power and volume, meaning the slightest increase in volume can be too much. Since the ZEN DAC V2 doesn’t have a way to reduce the gain, the impedance adapter helped me in this case, so it’s an overall nice addition.

The included cable is a 2-core, silver-plated copper cable with terminates in a 3.5mm connection. It’s fairly light yet sturdy and is overall good quality and looks very nice too. It’s a drop-down cable, not one that hooks over your ears, so there is some microphonics present as a result of that design choice. One thing you need to watch out for though is the 0.78mm 2-pin connectors can only be attached to the Sigma in one way due to the plastic insert design, so just be aware when you’re connecting the IEMs to the cable.

Lastly, the included leather case is very nice and feels premium. It has enough room for the IEMs, impedance adapter, and dongle DAC. It stays closed with the clasp, and overall I really like the size and the material.

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The Twistura Sigma is a bullet-style IEM. They have a shiny polished aluminum shell with a transparent resin “window” that partially allows you to see inside the IEM. It’s a sharp-looking design and feels very solid and premium. The polished aluminum shell does attract fingerprints, so keep a microfiber cloth handy.

Comfort is excellent, I did not have any issues with ear fatigue at all. They do insert a little further than over-ear IEMS, but it’s not too invasive. If you’ve used bullet-style IEMs before then there’s nothing new here. Once inserted the Sigma fits very snugly, and after a moment you get a good seal from the ear tips and then you’re good to go. The Sigma is also incredibly light at 2.7 grams, which contributes to its excellent comfort.

As mentioned before when connecting the earbuds to the cable there is only one way in which they can be connected. Both the earbuds and the cable connectors are labeled L and R, making it easy to not mix up the connections.

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The Twistura Sigma is easy to drive, but you need to give it more volume and power than the specs would have you think. It can still be powered from any smartphone, budget DAP, or basic dongle DAC, but the Sigma does benefit from more power.

The Sigma sounds fairly neutral and is highly resolving. The bass lacks presence in the mix but sounds well-controlled. The midrange is well-layered and engaging, with more of a focus on vocals, and the treble is extremely polite but doesn’t carry a lot of energy. This all leads to a sound that isn’t upfront and in your face, but instead maintains a distance, as if to not offend you. The Sigma is not an energetic IEM, instead relying on its resolution, accuracy, and smoothness to win you over.

It sounds more on the intimate side, and with a focus on vocal presentation, the Sigma is ideal for jazz, acoustic, folk, and live tracks. Really, anything that emphasizes vocals sounds great. A few tracks that really sound great to me when listening to the Sigma are Limo Wreck by Soundgarden (Chris Cornell’s voice is really nicely rendered on the Sigma), Roads by Portishead, and the MTV Unplugged version of Frogs by Alice in Chains.

Bass

The bass doesn’t show very much presence, especially the sub-bass, so don’t expect any deep rumble impact here. The mid-bass shows more impact and note weight, but is very well controlled. The Sigma is definitely not a bass-focused IEM, but the subtle nature of the bass performance did grow on me.

Midrange

The midrange is the best part of the Sigma, in my opinion. Instruments and vocals are layered well and have a slight warmth. There’s also a bit of energy here that carries into the upper-midrange helping the Sigma sound more engaging, and balancing out the controlled bass. Vocals are placed in front of the mix but aren’t overly forward. The Sigma has excellent clarity for both male and female vocals, with a natural sound and smooth response that leans toward authenticity.

Despite the vocal focus, instruments don’t get lost in the mix. They exhibit the same clarity and natural sound as the vocals, with just enough accuracy to satisfy most critical listeners.

Treble

The treble, like the bass, doesn’t exhibit a lot of presence. It’s extremely polite and controlled, and the energy from the midrange doesn’t get carried forward here resulting in a more relaxed treble response. Clarity and detail remain, but there’s a pretty sharp roll-off towards the upper treble that makes the Sigma sound intimate. The benefit here is that tracks that would usually sound sharp or bright are not fatiguing at all, so if you are sensitive to sibilance or brightness the Sigma might actually be perfect for you.

Soundstage and Imaging

The soundstage of the Twistura Sigma is average, even for an IEM. While overall it sounds a touch intimate, I never thought it was too much as it’s spacious enough to enjoy most genres.

Imaging performance is excellent though, with layering and placement of instruments and vocals. Nothing ever sounded too cluttered or overwhelming.

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The Twistura Sigma is not an IEM that will immediately wow you. It doesn’t have any exciting, flashy, or exotic sound nuances that will be front and center. It took me a while to warm up to it and to understand the nuances of the sound signature that Twistura was going for. This is not an everyday IEM but it is versatile enough to be an everyday IEM for some. It lacks bass presence and texture, and the treble really falls short at times, but the midrange is very good, and very enjoyable once you listen to the Sigma for a while. Bassheads and trebleheads should look elsewhere, but if you have an aversion to sibilance or brightness, or if the majority of music you listen to is jazz, folk, acoustic, and live recordings, the Twistura Sigma may be a really good option for you. $79 USD is not really an impulse buy territory, but if the above criteria are what you’re looking for I would highly recommend you consider the Sigma.

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