Hearing the Same Thing

With the Bose^® Personalized Amplification System™ family of products, most of the time (almost always) if things are sounding good on stage, (volume, overall mix) then things are sounding good in the audience. But on occasion you run into situations where that doesn't seem to work.

Sometimes enthusiastic players say things like, "With the Bose^® Personalized Amplification System™ family of products everyone is hearing the same thing" and this can lead to a some odd expectations. It is true that if there is only one point of amplified sound for each performer, everyone (performer, other performers, audience) are all listening to the same sound source. But because of room acoustics, what is heard may be different depending on where you are in the listening area. Acoustics vary because of one's position in a room (proximity to sound sources, nodes, anti-nodes, boundaries).

Recently there has been some discussion on the Bose^® Pro Portable PA Community (Mix on the stage sounds good but... ) about muddy sound in the middle of the room. This led to several of us sharing similar experiences. This is not a failure of the System or proof that it doesn't work. It is an interesting study 'in the wild'.

We might all be listening to the same source, but that doesn't mean that we will hear the same thing. This article addresses some reasons why. But first you might be wondering:

• What happened to "Everyone is hearing the same thing"?
• If everyone is listening to the same source, how can they be hearing different things?

This is what we are talking about.

The Mix on stage sounds good, but ...

Symptoms

• Sounds good on stage, sounds muddy in the middle of the house.
• Overall volume is fine, vocals are indistinct in the middle of the house.
• Bass frequencies sound fine on stage, but overpowering or out of balance in the house.
• Sound in the house is better (audience standpoint), when standing instead of sitting.

Causes

Here are a few factors that seemed to contribute to the problem.

• Large, reverberant space
• Elevated stage
• Listening audience seated
• Bass Regeneration

What seems to be happening

• The audience is hearing more room reverberation than direct sound.
• This can happen when the L1 Cylindrical Radiator^® loudspeaker is 'aimed' above the listeners. This can be a combination of seated audience and raised stage. This can happen when the room is large enough to have long reverberation times.
• Large curved surfaces can put the audience at the focal point of a concave reflector.

Solutions

Turn Down the Volume / Feature the vocals

Do the sound check by setting vocal levels first. You want to have someone listening from the centre of the room to help find the optimum setting for the volume and tone settings. Don't be surprised if the volume is lower than you expect. If the volume is too high, you will be feeding the reverb more than reaching your audience.

Set up the instrument volumes based on the vocals

Bring up the volumes of the instruments so that these are correctly balanced in relation to the vocal. You may need to roll back on the low frequencies in your mix. These low and low-mid frequencies can contribute to the reverb and the perception of 'muddy' sound. I have often read the people will set up their band mix starting with the Drums. I strongly recommend that at least in challenging rooms (big, boomy, resonant, muddy...) start with vocals (clear, intelligible) first. Then mix the band around the vocals.

Aim the loudspeakers at the audience / Reduce Slapback echos

Tilt the L1 Cylindrical Radiator^® loudspeaker downward (just a little) to 'aim' it toward the audience (instead of over their head). The downward tilt should also alleviate the slapback echo that can be coming from the back wall. Be very cautious when tilting the System. You only need to raise the back edge a tiny bit (probably under 2 inches" to get results. Be extremely careful that your System is physically stable and safe.