The mobile podcast studio #EchoStopBox is a solution for professional voice recordings. Nothing is worse than room reverb ruining a great podcast recording. A lot of audio is recorded in large, empty offices, conference rooms or other empty spaces without carpets, bookshelves, plants, sofas or curtains.
In fact, a cosy living room would be a far better acoustic location for voice recordings. Hard surfaces, on the other hand, make recordings difficult to understand due to room reverberation. It becomes exhausting to listen. The mobile podcast studio #EchoStopBox is a solution for this.
The biggest problems in recording rooms are reflections and flutter echoes. Both cause unpleasant sound colouration. In addition, disturbing resonances can occur on surfaces such as tables or doors. This can be reduced either by broadband absorption (damping) or by diffusers (scattering).
Absorption is much easier to realise on the move. Based on this experience, I developed the #EchoStopBox. A system that can be easily transported and set up. And which has the greatest possible effect with the smallest possible dimensions.
My mobile Podcast studio #EchoStopBox
The #EchoStopBox consists of a highly effective acoustic foam at its core. I produce the #EchoStopBox with a thickness of 10 cm as standard. This not only has optimised acoustic properties, but the elements with their very low dead weight (approx. 1 kg per piece) can stand on their own or be stacked without stands.
The thickness of the material is also decisive for the acoustic effect – depending on the frequency: the #EchoStopBox can absorb up to 100 % of the sound down to low frequencies of 160 Hz, thus reducing room reverberation. Even at the very low masculine (fundamental) tones of 125 Hz it still achieves almost 50 % absorption.
EchoStopBox is best as 5-Pack
Five acoustic blocks are packed so that they still fit on the back seat of a car or in the luggage compartment of a train. Or they fit together with one person in a smaller lift and can be carried up a spiral staircase.
The set is particularly impressive because of its low weight of just over 6 kilograms. The blocks are equipped with an edge protector on the inside, on both sides and laminated with an acoustically permeable fabric. This protects them from dirt and damage.
Five blocks can be used to build a free-standing cabin, which achieves an optimised effect due to the damping on both sides.
If the blocks are transported more frequently, an additional corner protector is recommended, as otherwise the fabric at the corners can quickly be worn. (PVC or silicone)
Background: Sound damping (absorption)
When sound waves hit the soft, porous and deformable surface of an acoustic foam, they are completely or partially absorbed. Physically, this is the direct conversion of the kinetic energy of the airborne sound wave into heat (which cannot be felt with the hand).
The degree of absorption depends on the thickness and density of the foam. It is also dependent on the sound frequency. I paid particular attention to this when selecting the material for the mobile podcast studio #EchoStopBox.
Remember: the thicker the foam and the higher the sound frequency, the stronger the sound-absorbing effect. In addition, the surface structure is decisive for the damping. A
fine open-cell structure is ideal.
Double effect with a simple trick
Because it can be set up freely in the room and close to the sound source (mouth), it has a double effect: it dampens (absorbs) from behind and in front equally.
Men, by the way, have vocal folds about a quarter longer than women. They produce a fundamental tone of around 125 hertz. The normal (fundamental) frequency of the female voice is 200 hertz on average.
Both fundamental frequencies are decisively damped by the #EchoStopBox – quite different from many off-the-shelf products.
This is because most off-the-shelf products do not sufficiently absorb the frequencies that are crucial for the human voice and are usually too bulky, complicated to set up and also too heavy to transport for mobile use.
The truth about Damping Mats and Mic-Screens
Maybe you’re wondering: Why go to all that trouble? Isn’t it enough to just stick some pyramid-patterned damping mats on the wall or build the microphone into a nice mic screen? The truth is: No. Save your money for something better.
The mic screens have minimal effect. They dampen the incoming sound (one’s own voice) so that it does not propagate as much into the room and comes back reflected. Sounds from the room (or outside) are hardly diminished, however, because they simply travel around the screen.
And the thin insulation mats on the walls are also mis-invested money. If you later switch to broadband damping or absorption, you will have the effect that the highs and mids may be doubly damped. This can even lead to an unnatural sound development in the room.