The IE40 Pro has great sub-bass extension with slightly less quantity for a full-bodied reproduction. The bass decay has moderate pace while the bass texture is rendered relatively smooth. The mid-bass has fair quantity and the slam is presented in a punchy manner. Each bass note is articulated well with precision and it brings impact to the overall sound. The authoritative presentation provides an engaging rumble.
The midrange on the IE40 Pro is rendered cleanly with the vocals taking on a more laid-back manner. It boasts good transparency. The lower mids has a fair amount of body and male vocals have slightly reduced presence. The upper mids is not the most forward but female vocals are expressed with great definition with a lower intimacy level. There is a detailed and controlled vocals performance.
The treble is extended well and it takes on a bright presentation which helps to create a lively performance at the top end. There is no sibilance and harshness. The presentation is sparkly and it brings a shimmery effect which elevates the overall engagement level. The amount of air rendered is moderate and the crisp is well-defined. The treble has fair mastery and it helps to reduce the overall density.
The IE40 Pro has a moderately natural expansion and the width magnitude is excellent to prevent any signs of congestion. The depth has an effective amount of space rendered. Positioning of vocals and instruments benefits from the width greatly. There is a spacious feeling.