With “Home Theatre’s” there are issues to check when having difficulty in getting a smooth, flawless soundstage from your front left speaker across to the centre speaker and then to the front right speaker. On the other hand you have to know if the majority of your audio imaging appears to fold over into the centre speaker only.
If that is the problem you are having, then it’s time to cautiously measure the centre-speaker distance (inches or cm) and level (volume) program it in your Dolby Digital receiver’s setup menu. This also applies to all other speakers’ connected to your Dolby Digital audio system. Many Hi-Fi and Home Theatre disciples seem to run the centre a little too loud, not sure why. For that reason you have to fine-tune the centre speaker level for its quality of sound and loudness (85dB), make sure its dialogue has good tonal and clarity, but not louder than the other channels. Use the volume test meter (VU) to read the volume level. A perfect balance between the other speakers has to be there with links to where you are seated.
Make an effort to place your Left and Right speakers so their front panels are even with the centre channel, then move the centre channel slightly further back, if possible wall-mount it just below the Home Theatre screen or Plasma TV, that’s just another option. When the three main front speakers form a logical “Arch” facing your sweet spot settee, with the centre speaker slightly further away, then you will experience favourable improvements in the front soundstage.
Centre Speaker Intelligibility
Even though most conventional forward-firing speakers are directional to a degree, it also depends on the output frequencies of its sound. Especially high treble can be quite directional, and lots of midrange sounds, where most voices exist in. It’s easy to confirm this effect by just standing in front of your centre speaker and walking well off to either side, or “off-axis”. You will hear the midrange and highs become less detailed and voices become a bit lifeless. Characteristic and accuracy are among the prime requirements of any centre-channel speaker. If you seem to have trouble understanding movie dialogue, then start with increasing the volume of the centre speaker using your Dolby Digital receiver’s speaker setup menu, and then try these solution:
In situations where centre channel is above the full-size TV, then it will be well above the height of your seating area, you will have to modify the focus issue by getting a couple of rubber doorstops and wedge them under the rear part of the speaker base so that the front of the speaker fires directly towards the listening sweet spot. Most quality centre channels have broad horizontal dispersion, but it’s always important to have the centre speaker aimed toward the listeners. Options are if your centre speaker is on a shelf beneath the Screen or TV; angle it upwards towards the sweet spot area. You must have noticed that in large movie theatres the centre channel is always behind the centre of the screen and carefully horn-loaded to direct the dialogue over a broad horizontal angle and a narrow vertical one, to avoid sound bouncing off the ceiling, which can hinder its clarity. Similarly never position a centre channel more than 15 inches above the LCD or Plasma TV display.
When you reposition a speaker you will feel like it has alter its sound. So, audio speakers are very dependent on your particular placement setup of your room. The tonal changes that can occur are generally minor but in some unique cases they can be quite audible. But with a bit of fiddling with the two fronts and centre speakers placement you will be able to restore the tonal balance
The results can be charismatic, Just changing the centre-channel location will certainly determine how neutral or transparent your centre channel loudspeaker will sound, and how well it will tonally blend with your front left and right speakers.
It is exciting to experiment with multi speaker placements for best results, and most of the time it can take a whole day or two. But if you can identify obvious tonal differences between your centre and the main left and right speakers and you find those tonal differences distracting, then it’s a must to experiment with your speaker’s placement. Every room is different, so experiment with different locations, even sliding the speaker a little to the left or right.
For a superior centre channel sound coverage especially with a large 100 inches screen and a front mount projector, experiment using two centre channel speakers, one above and one below the screen. This is an advantage for several viewers at the same time. When two centre speakers running in parallel it will image the dialog to the centre of the screen, the effects will be just like your local Cinema; This dual centre-speakers configuration will also reduce the effect of the location on the tonal balance. Even when you are walking around the room, the tone of the dialog (voice) is captivating.
Enjoy your Music.
Audio Recording Engineer