Yamaha Presence Speakers Explained

[JamesN]

There have been a lot of questions floating around the board regarding Yamaha receivers and what “Presence speakers” are used for. There have been some high-level explanations provided by various members, but I thought I would take a stab at a more detailed explanation. I hope it proves helpful.

Overview
Presence speakers are part of an overall technology that Yamaha calls Digital Signal Processing (DSP). DSP is an attempt to recreate the sonic characteristics of external environments and apply them to music and film soundtracks in one’s home. To understand how this works, we first need to think about sounds and how we perceive them in real-world environments.

When we listen to live music, we are not just hearing the actual instruments being played. We are also hearing the environment in which they are being played. If we could listen to a violin in a controlled anechoic chamber, it would sound dull and flat. We might be hard pressed to even recognize it as a violin. That is because when we listen to a violin played in a concert hall, we hear not only the original sounds emanating from the instrument, but the countless reflections, echoes, and reverberations of that sound as it interacts with the physical environment, arriving at our ears at different times and from different directions. The combination of original and ambient sounds determines the overall character of what that particular instrument sounds like in that particular environment.

The architects who designed the great music venues in the world understood acoustics and the interaction of sound and environment. The great concert halls were “tuned”, much as fine musical instruments are tuned by their creators, to enrich the original sounds of musical instruments with the characteristics of the environment. Every real-world venue has its own sonic characteristics, its own sonic “footprint”.

DSP Technology
Yamaha DSP technology seeks to recreate these sonic footprints of real-world venues in the home environment. To accomplish this, Yamaha travels to famous venues and electronically measures the specific ambient characteristics of each environment. They start by placing multiple microphones at strategic locations within the environment and recording known test sounds emanating from the sound stage. Each microphone receives a mixture of original sound and ambient sound. Because the original test sounds are known constants, they can be effectively “subtracted” from the composite sound, leaving only the “blueprint” of the ambient sounds. (A gross oversimplification, but this is the basic idea.) Once the “blueprint” is created, it can be applied to any sound source to recreate the ambient characteristics of that sound in that particular environment.

In Practice
So how can DSP technology be applied to the home environment? Unfortunately, we can’t just create the ambient sounds and mix them in with the original sounds. The results would sound muddy and artificial. In a real-world venue, ambient sounds arrive at our ears from every direction. To recreate this at home, the ambient sounds need to originate from locations physically distinct from the original sound source (the main speakers). For ambience originating from behind the listener, the surround channels can be employed. However, for ambience originating from in front of the listener, we need an extra pair of speakers. Hence the need for front presence speakers.

The front presence speakers should be located higher above and to the outside of the main front speakers. Because they reproduce only ambient sounds, they do not need to be as large as, or of the same quality as, the main speakers. Small bookshelf or satellite speakers are perfectly adequate.

It should be noted that Yamaha’s flagship receiver, the RX-Z11 also provides for a set of rear presence speakers. More on this later.

Musical Applications
Yamaha calls the sonic blueprints of environments “sound fields”, and several different sound fields are provided to match different types of music. Different receiver models feature different sound fields. You should experiment with different styles of music and different sound fields. There are concert hall fields for classical music, jazz club fields for jazz and acoustic music, cathedral fields for organ and choir music, and larger venue fields for electric music. All are modeled after real-world venues. But don’t feel limited by the names Yamaha has given the sound fields. Try a jazz ensemble in one of the concert halls. Let your ears be your guide.

The overall effect should be subtle and realistic. If you are “hearing” the ambience, it is probably too loud in relation to the original sound. You should only notice the effect if you turn it off. The goal is realism. You should be able to close your eyes and believe you are somewhere else, listening in a real venue.

All of the sound fields have configurable parameters and you should feel free to experiment with them if you don’t like the factory settings (you can always restore the factory defaults). You can make a sound field larger or smaller, more or less reverberant. But always remember: less is more and the goal is realism.

Surround Sound
Yamaha originally developed DSP technology to enhance musical recordings, but it can also be applied to movie soundtracks and surround-sound recordings. A movie theater is just another real-world venue and has its own sonic blueprint, just like a concert hall, and Yamaha provides several movie theater sounds fields from which to choose.

Unfortunately, when we move beyond stereo musical recordings, things get a little more complicated. For multi-channel movie soundtracks with up to 5.1 channels, sound fields can still be applied. However, since movie soundtracks employ the surround channels for discrete sounds, the generated rear ambience must be mixed in with the original surround material and the result can sometimes sound muddy.

The front surrounds provide an added bonus that Yamaha calls “dialog lift”. Some of the center channel information is mixed in with the front surrounds, resulting in raising the perceived height of the center channel. For those with large screens, specifically front projection setups, this can make it appear as if dialog is originating from the screen itself instead of below it. The relative “height” of the lift can be adjusted by the user and the setting can be saved uniquely for each sound field.

When we move to 6.1 and 7.1 soundtracks and add rear surround channels, things get even messier. For all but Yamaha’s flagship receivers, the rear surround channels and the front presence channels share the same internal amplifiers. This means that the rear surrounds and the front presence channels are mutually exclusive—they can’t play simultaneously. The receiver decides which pair to enable and which pair to disable based on the source material. For 5.1 and fewer channel sources, the front presence channels are enabled and the rear surrounds are disabled. For 6.1 and 7.1 channel sources, the front channels are disabled and the rear surrounds are enabled. This means that for 6.1 and 7.1 soundtracks, the front ambience gets mixed in with the main speakers and the results can sound muddy. You also lose the dialog lift effect.

Many users don’t like to apply sound fields to movie sources because of the above mentioned limitations, and I can understand that. Personally I stick with the “Standard Movie” sound field for 5.1 sources and disable DSP entirely for 6.1 and 7.1 material. The one movie sound field I really do like is “Mono Movie” for older monophonic films. However, the factory settings are way too echoic for my tastes and I have dialed down all of the effect parameters to make it more subtle.

[Note: For Yamaha’s flagship receivers the above limitations don’t exist. The current top-of-the-line RX-Z11 has 11.2 channels with discrete amplification for each (7 discrete channels, front and rear stereo presence channels, and stereo subwoofer channels!) If you can afford one of these, you can afford a custom installer and you don’t need my opinion.]

Closing Thoughts
Yamaha’s DSP technology can provide a very realistic “you-are-there” experience for both musical and movie material. IMHO, it is much more effective for music sources than for film. Remember that all of the sound field parameters are fully configurable, so if you don’t like the factory defaults you can tailor them to your own taste. You can also disable DSP entirely and listen to the unadulterated source material. The ultimate goal is realism: to recreate the experience of listening to music and films in real-world environments and venues. Experiment and enjoy.