<p><code>low_freq</code> and <code>high_freq</code> are used for keeping the relevant
frequencies. These are meant to be the ones inside the range
\([ low \_ freq, high \_ freq ]\). Therefore, values outside this range are
removed.</p>
<p>For 2-dimensional objects <code>x</code>, this transformation is applied per column.</p>
    </div>
    <div class="section level2">
    <h2 id="value">Value<a class="anchor" aria-label="anchor" href="#value"></a></h2>
    <p>Filtered object with length/dimensions same wit