Very often, the terms soundstage and imaging get used interchangeably, and this is because the two are closely related, and each can have an effect on another. Soundstage and imaging are generally used to describe the ability of speakers to create an illusional three-dimensional sound space and place individuals instruments, or sounds within that space. However, these two are different properties.
So, what is soundstage and imaging?
- Soundstage and Imaging
- How is soundstage created
- Factors affecting soundstage reproduction
- Soundstage in headphones
What is Soundstage?
Soundstage refers to the apparent depth, height, and width of a recorded sound played via speakers. It may also extend in-front or rear and not just between the speakers.
If you close your eyes when playing a record via a properly set up set of speakers, the speakers should seem to disappear and instead be replaced by an imaginary three-dimensional spatial arrangement setting of different music sources. The three-dimensional sound space created is similar to a theater stage from which all sounds seem to emanate.
What is sound imaging?
Imaging refers to the ability (or lack thereof) of the speakers to position individual sounds within space/soundstage.
If you close your eyes when listening to a record, imaging is the ability where you can tell the direction the different musical sounds are coming from, or where each musician was standing at the time he recording was made giving the sound a three-dimensional presentation.
In short, imaging is how well your speakers create and reproduce individual instruments or performers in a virtual soundstage space. Often, when speakers image well, you can hear people saying that they can hear even the “air” around the instruments.
There are several factors at play in the creation of soundstage and imaging. There are three main ways of creating soundstage. You can either do it by the excellent placement of mics, or you can also add soundstage using reverb, delay, and adjustment plugins or by Mid/Side Processing.
1. The initial recording of sound
The first and significant element in the creation of soundstage or imaging is in the initial capturing or recording of sound. The following factors affect the production of the soundstage.
- A good recording area
- Mics that record it
- The position of the mics
To get a virtual soundstage to sound like a real world stage, the first step starts with choosing a great recording area with a wide and reflective environment. A good example would be a cathedral.
The second part of capturing a wide soundstage will be choosing a good mic setup and also selecting quality mics. Choosing a binaural microphone tends to give better results as they create a 3D stereo sensation or a realistic sense of “being there” to a listener. Binaural mics are best for recording realistic and natural imaging with a sense of a real-world soundstage.
One of the first tests to determine the idea of soundstage was done by John Culshaw’s production of Wagner’s Ring cycle. It was on a physical stage with different microphones placements including the famous Decca “tree” arrangement. In his experiments, the microphones captured the activities on stage to recreate the soundstage in stereo.
2. Playing around with reverb and delay
Another way to simulate a soundstage scene is playing around with reverb and delay.
Reverb or reverberation is like “echoes,” the sound bouncing off the walls so you can hear it several times. Simply put, reverb is the sound of a space. The use of reverb in recording adds depth and fullness to the music. The amount of reverb in a record will indicate the type of materials within the room.
Example
Areas with sound dampening materials will absorb the sound, and thereby reverberation will not be a lot. However, canyons or a cathedral are made of stone and will have high reverberation.
Delay is the time taken by reverb to get back to the listener eg, a second or 3rd time. Delays, when used effectively, can give a sense of wide space or closed spaces. Long delays give a simulation of wide spaces, while short delays give a sense of closed spaces.
3. Mid/Side Processing
In 1934, Alan Blumlein patented a mic technique which bought about the concept of Mid/Side processing.
The idea behind the technique was to recreate how the human ears hear a stereo image. Mid/Side processing technique has now become one of the highly effective ways of adjusting the spacialization of mix.
The mid-channel is the center of the stereo image, and when it is boosted, a listener hears a more centered sound. Alternatively, when the side channels which act as the edges to a stereo image are boosted, a listener hears a wider sound.
A basic setup for recording in Mid/Side uses two microphones, a cardioid microphone which is the mid and a bidirectional microphone for the sides.
For a more detailed read on Mid/Side processing, Click here.
- Speaker and amplifier design
- Speaker placement
Speaker and amplifier design
This also plays an essential role in the reproduction of a quality soundstage. Driver material and size, preamp and power amp components, transformers and crossover components all play a part in the speakers’ ability to reproduce sound accurately. Speaker dispersion patterns and speaker cabinet designs have also been touted as some of the factors that affect the character of soundstage.
Both tube power amplifiers and tube preamps are also known to have the biggest effect on soundstage compared to the solid-state amps.
Speaker placement
When it comes to speaker placement, I will point out that not all speakers are designed equal. Therefore, each pair of your home speakers need to be tuned differently to find the “sweet spot.” Finding a sweet spot could be twisty, long, and take most of your time. However, this process can be educational and fun for those knowledge seekers on how speakers work and interact with the environment.
As mentioned in the last paragraph, every speaker is tuned differently. Therefore, what works for other speakers might not work for you. If you are searching for a sweet spot for your speakers, here are some pointers to consider;
- The distance between the speakers
- Distance of the speakers from nearby partitions or walls
- Distance between a listener’s seating point and the speakers
- The height of the speakers with reference to the ears of a listener
- The vertical and horizontal angles of the speakers
Most people in the audiophile world always complain about how headphones are inferior to speakers in terms of soundstage and imaging. While to some extent, their statements are true, I think soundstage and imaging are almost to a large degree dependent on the quality of a recording.
Most people complain about the inferiority of headphones’ Imaging/soundstage compared to speakers.
But what does this mean? Personally, using my Sennheiser HD800 or my new Stax Headphones, I can place instruments in a given space around my head and can also perceive the size and dimension of the given space, is this not imaging and soundstage?
Though qualitatively listening to headphones is different than with speakers, it is quite evident though that headphones are also capable of reproducing soundstage and imaging.
