The Flex Acoustics Auralizer lets you hear – and play with – the effect our evoke and aQflex technologies have on the reverberation in a venue.

First, choose evoke or aQflex and switch them on and off to hear (and see) what difference it makes. Then, explore what impact the presence of an audience has on the reverberation time, or play directly with the sliders to get an idea on how reverberation changes the music experience.

The above frequency chart shows the reverberation time curves for the selected venue. Please note that the black curve represents the current settings and the coloured curves indicate the different situations with evoke or aQflex on/off and audience present or not.

Below the chart, you can further change the reverberation time at various octave bands. Simply press ‘Generate Reverb’ to apply your changes.

The model is based on approximate acoustic and geometric properties of actual halls.

Reverberation times are calculated with the basic acoustic formulas in agreement with hall volume and absorption data of audiences and evoke/aQflex. In these models, the audience is taking up approx. 1/3 of the floor area. Further, upholstered seating can be thought of as having the same impact on reverberation as a (seated) audience. So, if you choose ‘no audience’ the sonic result equals a hall without seating/audience.

While aQflex is applied in the entire ceiling area, evoke is incorporated to a degree that makes it possible to achieve the necessary, natural change of reverberation time required to be able perform all types of music within the same venue – from choir, orchestral and chamber music over brass music and opera to amplified music and spoken word performances. And every time with an ideal reverberation time that suits the current performance perfectly.

The dry/wet setting is chosen to resemble the actual sound at shows.

It is equivalent to the concept of critical distance: the level of reverberant sound is more or less constant at any position in the hall while the level of direct sound drops further away from the stage/loudspeakers.

The result is that we perceive the sound with a decrease in clarity the further away from stage we get. When absorption is added to the hall, the line of critical distance is pushed towards the back of the hall, which simply increases clarity for everyone in the room.

At any given position in the hall, the sound gets dryer when you add absorption, which is equivalent to a difference in the dry/wet setting.

Different sizes of venues have different values for ideal reverberation time for any given purpose. For instance, a hall of 5,000 m³ has an ideal RT of approx. 1.0s for pop & rock while a 25,000 m³ hall needs around 1.6s of RT in the 125 Hz octave band in the unoccupied hall to sound good.

This fact is adopted into the program, and further, different dry/wet settings for different size venues¹ are applied.

It is important to note that while a completely dry sound is preferred when listening back to music in your home, your car or on headphones, a somewhat wetter sound is preferred at pop and rock shows. It simply sounds too tame if the hall does not respond a little to the music especially at higher frequencies. It enhances the audiences’ sensation of taking part in a social experience, and the musicians feel connected to their audience and each other through sound¹.

Unamplified, classical music genres need reverberation not just to sound good, but also to acoustically amplify the sound level throughout the concert hall.

¹N. W. Adelman-Larsen, Rock and Pop Venues – Acoustics and Architectural Design (Springer, Heidelberg, 2014) (buy on amazon.com)