With the Covid-19 precautions we have had since March of 2020 a lot of communication I am involved with has been via Zoom, Skype, Microsoft Teams and similar apps. I notice that some people use these more effectively than others, both in terms of the sound and of the visual images of themselves. I will discuss, in this post, audio tips for more effective communication. Many of the audio tips are also included in earlier posts on this blog, especially the post SKYPE RIGHT, but I want now to review, and slightly expand, the best audio practice for online meetings, In the next post (after this one), I will add more visual pointers than I did in that earlier blog article.
At the time I wrote SKYPE RIGHT internet conferencing software was not used all that often for instruction in schools and business meetings. Now that Zoom, as well as Skype and Microsoft Teams, are being used commonly, it is worth considering, again, how to get the best quality when using these services. I certainly have participated in a number of online meetings where some participants did not have great audio or visual quality. So, this post, and the one that follows, expands on the points I made in SKYPE RIGHT and hopefully will be useful to everyone using Zoom and similar programs to replace face-to-face meetings.
Some factors which influence sound quality:
The acoustic environment where you are talking
Sound picked up by a microphone has two components:
Direct sound (from the person speaking directly into the microphone)
Indirect sound (sound from the person speaking that bounces off hard surfaces before being pick up by a microphone)
The sound of a choir in a large cathedral or an orchestra in a large concert hall can often be enhanced by indirect sound, often called “reverberation” or just “reverb.” I once attended a Christmas concert in Hallgrímskirkja in Reykjavik, Iceland. It is a tall church with an especially tall tower. But unlike most other churches the tower is not closed off by a ceiling but is open. Sitting in the first row of the church the reverberation time was several seconds. During congregational singing I could hear my own voice over my head even after I stopped singing. It was amazing.
BUT, when the Bishop of Reykjavik stood up to make some remarks (without a sound system) he had to speak in short phrases because otherwise the long reverb time would tend to garble his words. You may be thinking “Well, I only use Zoom or Skype from my office, living room, or kitchen so I won’t have long reverb times like a large church. But if the flat surfaces of your room (wall, floor, ceiling) are hard surfaces then sound will be reflected and mixed with direct sound being picked up by the microphone. No, you won’t have long reverb times as in a large cathedral, but the indirect sound, being delayed only slightly (compared to a large church) will combine with the direct sound at a fairly high level as the reflected sound will not have decayed all that much compared to being bounced around in a very large building. Some frequencies of the reflected sound will be out of phase and thus cancel out or modify some of those frequencies in the direct sound. That, as well as the short delay of the reflected sound, will often produce an unpleasant “hollow” sound that makes it harder to understand speech and certainly makes the speaker’s voice sound unnatural and more unpleasant to listen to.
The distance you are to the microphone: One way to reduce the problem described above is to talk fairly close to your microphone (think 6-24 inches). The closer you are the louder will be the direct sound so the unpleasant indirect sound will be greatly minimalized. But if you are using the microphone built into your laptop computer, desktop computer monitor, or even cell phone, you might find leaning in close to your laptop or phone can be a problem if you are also trying to be far enough away to make a good visual composition. I have been a part of Zoom and Skype conversations where at least one person talking sat back in a chair to make a good picture, but whose voice was hollow and sometimes even hard to understand because he or she was, perhaps, 3-6 feet from the microphone built into their laptop computer.
The type of microphone you are using: One solution is use a microphone that is not part of your computer. Some people will say “buy a directional mic so it will pick up your voice from a distance.” But even an extremely directional mic, such as a long “shotgun” mic often used by documentary film makers, does not do for sound what a good zoom lens does for pictures. Even a highly directional mic has to be close enough to the person speaking that he or she can reach out an easily touch it. That is why, in these days of Covid-19, you see television reporters holding a microphone with a long pole to get it close to a subject while they maintain social distancing. The camera can be farther back because it can make the subject seem closer by zooming in.
A good solution is to use an external microphone that is physically close to you when you are speaking in a Zoom or Skype meeting. You probably don’t want to hold a mic in your hand, since you might need your hands to operate your computer, think about a mic that is close to your body even when you are not holding it.
News anchors and people being interviewed at length often wear a tiny microphone clipped to a necktie or other piece of clothing. These professional mics usually need special power, called “phantom power,” and thus, to use them with your computer you will need a professional audio interface. They cannot simply be plugged into the tiny mic/headphone input of your laptop, tablet, or cell phone. Prices can vary. I especially like the ones made by Danish Pro Audio, but most of those are in the $400-$700 price range though some decent ones are made by Audio Technica in the $60-$200 range. But again, you do need to plug these into a professional audio interface connected to your computer. These mics are often called “lavalier” mics because in the days before modern tiny capacitor mics were available (such as when I was an undergraduate student in the early 1960s) worn mics were about the size of a hot dog and worn around the neck. Nowadays you see the term “lavalier” used for those mics (a good tip if you are looking at the web site of an online store) but a better term is “clip-on” mic.
Another very good solution is to wear headphones with a mic attached. Some of those are available as devices that can be plugged into your headphone/mic jack on your computer or tablet though the best ones, used, say, by network sportscasters, can be expensive and require a professional audio interface to your computer. There is also an advantage to listening in a Zoom conference on headphones. Noises in your listening room (dogs, air conditioners, outside car traffic, etc.) are reduced as well as being able to have the microphone attached to you.
Pictured here are two headsets with attached microphones that I own. One is a Bang & Olufsen headset with a small microphone on the cable going to the left channel (visible in the photo). It sits on my chest close to where a clip-on mic might be. The other is a Sennheiser headphone with a mic attached on a small “boom” so that it sits fairly close to my mouth. This is the best placement for a close mic and some performers wear these kinds of microphones even without the headset. The Sennheiser headphone shown is sometimes listed as a “Gaming Headset” because they are popular for certain online games and, as with the B&O headshot, are designed to be plugged into a computer or cell phone without needing a broadcast quality audio interface box. “Faceworn” mics (attached to one’s face around the head but without the headphones), when used on stage or by a clergy person in church, are often connected to a small radio signal transmitter (usually worn on the belt in back to be invisible when facing an audience). The signal from that transmitter is picked up by a special receiver farther back in the room that sends the signal out like a wired microphone. That allows the person speaking to walk around in a room without worrying about cables. Usually these are not needed for things like Zoom presentations unless you are a dancer or physical education instructor. Good thing. Wireless transmitter-receiver combinations can be expensive for ones that are truly reliable.
The quality needed to accomplish your task
If you look at microphone prices online you will see that some are very cheap while other costs hundreds or thousands of dollars. What do you need for a Zoom or Skype meeting? First you need to figure out your intent. Voice quality doesn’t have to sound all that natural to be intelligible. Telephones, especially earlier ones, purposely cut extremely low and extremely high frequencies in order to be intelligible using phone networks that provided dodgy quality in terms of sounding natural. I used to hate call-in radio shows because the voices of callers were so terrible sounding even though the words spoken by the caller could be understood. Today, some telephone technologies provide higher quality though usually a call-in from a telephone sounds lower quality than a broadcast quality feed. Yet people on high quality internet carriers (rather than phone services) can often sound so natural that network radio and television interviews are conducted using Skype (especially) so that most of the “telephone quality” is lost. Thus, if you are going to take best advantage of sound quality with Skype or Zoom, then try to use a high-speed broadband service if it is available to you, as well as a good microphone and, ideally, a professional audio interface to your computer.
The next issue is the quality of the microphone itself. The sound produced by a microphone goes through a pre-amplifier then sometimes another stage of amplification before it goes to a digital-to-analog (D-A) converter to produce the digital audio stream used over the internet. All these functions can be on a small audio chip these days (as in a cell phone) though, for the highest quality, they can be separate expensive units. Still, I am amazed at the quality that can be transmitted by a cell phone or computer mic compared to what was possible only 2-3 decades ago.
All audio devices – microphones, amplifiers, D-A converters, etc. – usually have a bit of built-in “self-noise” that can produce a hissing sound (or worse) in the background of the audio even if the audio is being picked up in a quiet environment. In addition, lower quality devices don’t transmit all of the frequencies we can hear evenly (meaning at the same loudness). Think of the difference in audio quality between old fashioned wired telephones, shortwave radio, AM radio, FM radio and high-end internet radio. The better quality you want, the better gear you have to use. Unless you expect to be interviewed often on network radio or television, or plan to present long lectures to a class, you may be able to get by with fairly low-cost equipment.
Still, try to avoid equipment that is too low end. A $15 external microphone may not cut it for you, but neither would you probably need a $700 mic just for internet speech communication. Even though low-end gear can sound intelligible, higher end gear is more pleasing to listen to and conveys a more professional impression than a telephone sounding voice. If you also plan on recording live music on your computer then you certainly would want, if possible, a good quality external audio interface box and some high-end microphones. For digitally recording live classical music concerts I usually use one of two stereo pairs: one pair costing about $4000 and the other $6000. But that would generally be overkill for speech communication only.
If you are thinking of using Zoom for a virtual music concert be aware that the audio quality for high end music via Zoom may not as good as you would like it. Especially, if you are trying to synchronously record several musicians, each in their own home, for a virtual concert it can be hard to coordinate all of the musicians because of the difference in delay from each musician over the internet. I have heard two well-done online virtual concerts by the choral group C4 (Choral Composer Conductor Collective) in which they used Zoom only for the video and used a program called Jamulus for the audio. See: https://www.c4ensemble.org/aboutc4.html and https://jamulus.io.
I have tried to keep this relatively short and to the point. If you have more questions feel free to ask them in the feedback link.
A professional audio recordist (“tonmeiser”) trains for a long time and needs to know a lot about audio technology and music/speech. If there is something you want to see expanded in a future post, then feel free to let me know. The “picture telephone” was something that was envisioned long before it became economical to do. With cell phones and cameras/microphone on computers, it is now common and easy. But it all takes some practice to make it truly successful.
My next post will deal with improving the visual quality of your Zoom meeting participation.
Interesting and good overview. Can you post the link to the Skype Right blog that is referenced? Thank you