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I don't know anything about audio-engineering or audio-gear...in fact I am not even sure if this is right forum for this type of question. Finally, I am not even sure if these are valid questions...I'd be happy if you could just refer me to some source where I could educate myself a bit...

I want to understand how an amp or a dac help to achieve sound imaging. I have a couple of scenarios that get more complicated (helps me ramp up my assumptions and questions).

2 Instruments

In this scenario, assuming a digital source signal, lets imagine 2 instruments one plays out of the R-Chan. the other out of the L-Chan.

Questions:

  • Would I be correct in assuming that it is the amplifier's responsibility to send the electric signal to the correct speaker?
  • does the DAC play a role?

3 Instruments

  • 1 instrument is on the far left (FL)
  • 1 instrument is on the far right (FR)
  • 1 instrument in the middle (M)

Questions:

  • How is the middle imaging achieved (is the signal sent in equal parts of L & R channel)?
  • again is this amp or dac or both?

A more complicated example

In this scenario, assuming a digital source signal, let's imagine:

  • 1 instrument is on the far left (FL)

  • 1 instrument is on the far right (FR)

  • 1 instrument in the middle (M)

  • 1 instrument between FL & M

  • 1 instrument between FR & M

  • How is this kind of imaging achieved?

2

Very simplified. I assume a typical stereo setup, two speakers and no subwoofer.

.1 The amplifier has two channels. The job of the amplifier is only to amplify the input signals: left input signal is amplified and sounds from the left speaker, right input signal is amplified and sent to right speaker. The amplifier should not add anything or modify the signal.

.2 The DAC converts the signal from digital to analog. The output from the DAC is the two channels, left and right, that goes to the amplifier. The digital signal the DAC receiver already has the left and the right sounds as part of the digital signal. The DAC should only convert between digital and analog, not add anything or otherwise modify the signal.

So, the answer to your question is that the information on where and instrument is heard is already in the digital signal you send to the DAC and further then to the amplifier and the speakers. Ideally neither of these should add or modify the signal only make it hearable and stronger.

In the first example, one instrument is in left speaker and another in the right speaker. In both cases this information is already in the digital signal the DAC gets as input. This information was put into the digital signal by the mixer, often through a software program called a DAW. Examples of this kind of software programs are: Audacity, Reaper, Garageband, Logic Pro, Cubase, Protools, ... the list goes on. All of these can create a digital signal with one instrument in the left channel and another in the right.

In the second example, one instrument is heard from the middle. This is done in the DAW by sending the instrument signal equally to both channels.

The digital signal could be sent to the DAC in a variety of different ways. One way is from a CD, another is over internet, as example from Spotify.

4
  • Thank you...could u also comment on the more complicated scenario? Another follow up question, when I see people talk about amplifiers they talk about sound imaging...for example this amplifier does better sound imaging than some other amplifier...from your description it sounds like the amplifier actually has nothing to do with the imaging? – hba Feb 24 at 19:05
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    @hba The imaging is created in the recording process. The quality of the playback equipment may make the recording qualities more discernible or apparent but they do not change the mixing or imaging that was recorded. (turntables can effect imaging) Listen to some late Beatles recordings. – Alaska Man Feb 24 at 20:58
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    The imaging is interpreted by the brain according to a number of clues the ears hears. In the mixing phase you can use a few different techniques to create these clues -- slightly different if you expect the listener to use headphones or speakers. The most common solution for speaker listening is to simply modify the volumes using the pan control. Far left = only left speaker, mid= same amount in both speakers, places in between = adjust to taste. – ghellquist Feb 24 at 22:18
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    Imaging is talked a lot about among so called HiFi people. Some of it is what I tend to think of as psychological rather then technical or physical. In my humble mind, imaging is influensed most by the combination of type of speakers, their positioning and to a very, very large degree by the room. If you want to improve imaging start with the acoustic treatment of the room and speaker placement. All else comes miles after that. Amplifiers above a certain level of quality (ie not the cheapest Amazon China) makes extremely little difference compared to room acoustics. – ghellquist Feb 24 at 22:23

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