How to organize a low-cost hybrid session at a scientific conference?

In Januray of 2022, we organized a special session—Geometría Algebraica: la Aplicada, la Computacional y la Numérica—at the Congreso Bienal de la RSME (Biennial Congress of the Royal Spanish Mathematical Society) in Ciudad Real, Spain. Unfortunately, due to the pandemic situation with the Omicron variant of the SARS-CoV-2 in Spain, many session speakers—9 out of 16—could not participate in person. Because of that, we were forced to transform an on-site session into a hybrid session at the last minute. Moreover, we had to do so with minimal support of the organization—they only provided (loud)speakers. Fortunately, the hybrid session was a success; because of this, we feel that we can share our wisdom since people tend to think that this is harder than what it actually is.

In this post, we will show how an on-site session for around 30 participants—it may work for more—in a room can be turned into a low-cost hybrid session using today’s technological advantages. Our point is to show that we don’t need highly specialized technology to organize a successful hybrid session in this highly technological world.

What means that a hybrid session is successful?

An on-site or on-line session is successful if the following three requisites happen:

Every speaker can give Eir¹ presentation in the assigned time frame.
Every attendant can see and hear the given presentation².
Every attendant interested in asking a question can do so up to time limitations.

It is so natural to extend these requirements to a hybrid session. However, satisfying these requisites is harder in the hybrid session because each environment—the on-site and the on-line session—works differently. On top of that, we have to alternate between these two environments. For example, we have to guarantee that a talk given by an on-site speaker is not only followed by the on-site people but also recorded and streamed properly to all the on-line participants. If we are not careful, the latter might restrict the speaker’s movement, making that E cannot take advantage of Eir body language to give the presentation in the room. Thus making the on-site talk just like an on-line talk, but in a bigger room and with people accompanying Em in the room.

What do we need for a hybrid session?

Taking into account the above, to perform a successful hybrid session, we need:

One or two computers with a good Internet connection.

To interconnect the components and the in-site and on-line settings.
An streaming/video-sharing platform.

To communicate between the on-site and the on-line participants.
A projector (and the needed adapters).

To transmit the on-line presentation and the on-line participants to the on-site participants.
Speakers³.

To transmit the audio from the on-line room to the on-site participants.
A camera.

To record and transmit the on-site presentation and the on-site questioners to the on-line participants.
A wireless microphone.

To record and transmit the sound of the on-site presentation and the on-site questions to the on-line participants.
A presentation remote.

To pass the slides without the need to approach the computer.

Of course, it is not enough to know the components of a machine to make it work. For a successful hybrid session, we need to set up correctly the above components. For this, our recommendation is to do as follows:

All computers should be connected to the streaming/video-sharing platform.
The same computer should be connected to the speakers and the wireless microphone.

The reason for having this is to avoid a feedback loop in the audio. Most streaming/video-sharing platforms do not reproduce the sound emitted through the speakers and recorded in the microphone of the same computer, thus eliminating the problem. Note that we are considering a session where the speaker can be heard well if E speaks in the room, so no additional arrangements are needed for the sound.
The computer connected to the projector should be the one whose screen is shared through the streaming/video-sharing platform.

In this way, the slide presentation is shared directly with the on-line audience guaranteeing a better quality than sharing a recording of the projection of the slides. Of course, when an on-line speaker presents, this computer will not be sharing the screen but the corresponding on-line speaker.
The computer connected to the camera should transmit video at the highest possible quality.

This is only important if not every presentation is with slides, such as blackboard presentations. In this case, the camera must record the presentation with sufficient quality so that what is being written or shown can be seen with enough quality.

We should try to have 20 minutes before the session to try the set-up and guarantee that everything works properly. This time is critical the first time since it allows one to correct any problems that might arise.

Making a low-cost hybrid session

To do the above setting, it might seem that one needs expensive equipment to guarantee that everything works well. However, this is far from the truth. First, we should note that a conference presentation needs neither extremely high-quality image nor high-quality sounds. It needs good image and good sounds, but there is no need to employ the state-of-the-art technology more suited to the needs of an artistic live event than to the needs of a scientific event. Second, many of the technological components listed above can be found in the pieces of technology that we carry with us. As of today, many of us have laptops, phones, headphones and many more technological pieces that give sufficiently good technology for making a hybrid scientific session.

Let us go piece by piece:

Computers with a good Internet connection.

If the room does not have computers, we should use laptops instead. For the Internet connection, we should be careful that the eduroam setting is properly set up so that it works at the institution we are in.
Streaming/video-sharing platform.

If your institution offers zoom or other platforms, there is not much to do. However, as of today, there are reasonable open and free alternatives such as Jitsi meet that work reasonably well.
A projector.

We should expect to find such a device in a room where an on-site session was gonna take place.
Speakers.

Depending on the room, the speakers of the laptop might suffice. However, as of today, one can find a lot of very cheap speakers that one can connect to the computer. Note that we are reproducing a person speaking, so the sound quality doesn’t need to be perfect.
Wireless microphone.

Regular Bluetooth headphones with microphone—usually used for the phone—are an excellent cheap substitute that one could already have. One can find for less than 25 euros many reasonable versions of these. However, if one has wired headphones with microphone, one can connect them to a phone connected to the streaming/video-sharing platform, so that the phone will record and transmit the sound. This last solution would then be very similar to the standard microphone connected to a box that one carries around in big talks.
Camera.

Although a professional camera is always better, the current cameras of laptops (and tablets) have a very decent quality. In general, a laptop camera will have a resolution of 720p which is not ideal. However, the recording of the on-site presentations will not be seen in a huge screen but in a computer screen, for which this resolution is sufficiently good even to read what is being written in a blackboard presentation.
A presentation remote.

An on-site speaker likely has one. However, if one has a wireless mouse, this device can be used as an alternative.

In this way, one can for sure set up a seminar room in a university for hybrid sessions with a budget of fewer than 100 euros. Moreover, this low-cost solution allows us to prepare for the eventuality that we have to convert a planned on-site session to a hybrid one where both on-site and on-line participants can enjoy the session.

We will be using the Spivak gender-neutral pronouns (E/Em/Eir) in this post. See Spivak, M.D. (1990). Personal Pronoun Pronouncement. In Spivak, M.D. The Joy of TeX: A gourmet guide to typesetting with the AMS-TEX macro package (2nd ed., p. xv). American Mathematical Society. for the original reference for these pronouns. An interesting point to note is that, as of today, the solution a person gives to Spivak’s Exercise PPP.1 indicates Eir underlying assumptions about the possible genders of a person. ↩
We note that this might not be possible for blind/deaf participants. In this case, we should implement specialized solutions—subtitles generators, oral descriptions of the slides, etc.—to compensate for the problems produced by not seeing or hearing the presentation. As we don’t have any experience with this, our low-cost solution will assume that there are no blind/deaf participants. ↩
Loudspeakers, not the people giving the talks! ↩