How do I get a good sound for online music teaching?

There are many factors that are crucial to achieve a good sound result when talking online. Regardless of the software platform used (Skype/Zoom/doozzoo), the most important thing is the hardware setup and proper use. It's just like in a sound studio. You need good equipment (which doesn't have to be expensive) and you need to use it correctly. 

In principle, there are 3 phases that play a role in the sound:

1. INPUT - input or recording of the incoming signals e.g. microphone
2. PROCESSING - processing in the computer & transmission on the internet
3. OUTPUT - output of the signals e.g. headphones

1. INPUT

Technically, the process is always the same: An analog audio signal is digitized (A/D conversion) and can then be further processed by the computer.

In practice one can distinguish between 3 possibilities:

1.1. using the internal, built-in microphone via the sound card in the computer.

Here the sound quality depends on the quality of the microphones and the sound card in the computer. Often, very poor microphones are built into inexpensive computers and these are then not sufficiently acoustically decoupled from the fan, so that the other side perceives strong fan noise.

1.2. use of a headset (headphones with microphones) decouples the microphone spatially from the computer housing and the possible noise.

1.3. use of an external audio interface.

Instruments or microphones can be connected directly to an external audio interface. Audio interfaces usually allow the connection of multiple input sources and, depending on the design, also to mix them. The audio quality can be greatly improved with a good setup of audio interface and microphone. Depending on the application, there are different suitable devices.

Note: Basically, it should be noted that with all web conferencing programs, including doozzoo, only channel 1 and 2 are transmitted. With multi-channel audio interfaces, you have to make sure that all signals that are to be transmitted are routed to channel 1/2 so that the other side can hear the audio signal.

PROCESSING - There are 3 factors that play a role after the signal arrives at the computer.

2.1 The software platform that transmits the signal.

All web conferencing programs, such as Skype, WebEx, Zoom, etc, are optimized for voice transmission. This means that the sound components that could cause problems in voice transmission, such as low frequencies, hum, and high frequencies, such as noise, are eliminated. In music transmission this leads to the fact that crucial frequency components are missing.

In addition, echo cancellation is also permanently active in common web conferencing solutions, which means that audio signals cannot be transmitted without mutual interference when teaching music. Other filters, such as noise suppression, are used to suppress background noise, such as fan noise. However, these filters lead to a sometimes complete loss of the whole signal, especially with polyphonic and diffuse sounds, such as piano or drum cymbals. The third algorithm that causes problems with music is Auto-Gain. Auto-Gain provides an automatic volume adjustment. For speech this is quite useful, but for music the dynamics are completely lost.

Doozzoo makes these filters touchable and you can turn them on and off in the pre-session check depending on the application to get a free sound in full frequency range. 

2.2. Settings in the operating system

It should be noted that in the operating system of the computer also filters can be switched on for improvement for voice transmissions. This is especially true for Windows. Here is the link to the settings:

https://support.doozzoo.com/a/solutions/articles/103000020038?lang=en

2.3 Internet bandwidth

In general, the quality of the transmission also depends on the amount of data that can be transmitted per time. The more stable and faster the internet connection is between teacher and student, the better the audio quality. If the internet connection is poor, the audio may drop out. 

For all general settings please read this tutorial. You can also find a bandwidth test here:

https://support.doozzoo.com/a/solutions/articles/103000019989?lang=en

3. OUTPUT - Playback via loudspeakers or headphones

3.1 The best results can be achieved by using headphones or a headset. The headphones ensure, as in a recording studio, that the sound from the other side is not sent back through the microphone. In doozzoo it is possible to select the "headphone mode" in the pre-session check. This disables all filters.

3.2 If you work with the built-in or external speakers, you should select the "Speaker-Mode" in doozzoo, so that the other side does not hear any echo. Then, however, the echo cancellation filter is active, which eliminates the signals of the other side from the signal to be transmitted. This is not noticeable during conversations, because conversations are serial. In music lessons, however, there are simultaneous sound events. E.g. the teacher speaks while the student is playing to give him an instruction, where by the sound of the student breaks away at the teacher. Or the student is supposed to sing to a chord of the teacher; in this case the echo canceller eliminates the piano on the student's side, so that these frequency components are also lost in the student's voice. The teacher then hears the voice strongly altered or not at all. 

CONCLUSION:

With doozzoo an optimal setting can always be found. But you have to consider the technical and sound conditions. This is not as easy as with Skype, because there all filters are active, but you can achieve an excellent sound for music lessons with doozzoo. 

In doozzoo, in addition to the flexible filters that can be switched off, it is also possible to switch from mono to stereo and to up the audio bitrate to up to 192kHz/s.

Simple setups for playback:

1. The simplest setup is, of course, a laptop with a microphone and built-in webcam. Then select the speaker mode in doozzoo and adjust the Windows settings if necessary: https://doozzoo.freshdesk.com/en/support/solutions/articles/36000105515-windows-10-setup-and-sound-improvements
2. Computer with headphones or headset -> doozzoo in headphone mode
3. Computer with external speakers -> select speaker mode in doozzoo and make sure that the speakers are not too close to the microphone and interfere there.

General tips:

Basically, the sound conditions of the instrument and also the room play a role in choosing the right setup. Not everyone can work well with headphones covering the ears. Small clip-on headphones, such as those used with cell phone headsets, may be useful. Wind players should be careful not to blow directly into an internal microphone on the laptop, as these microphones are overdriven by the sound level of the instrument.