Peter Lane

3 Tips for Better Worship Livestreams – Audio

Posted on by Peter Lane

image: Freepik.com

Ok – having just narrowly prevented myself from starting yet another article with a variation on the theme of “Covid has Changed the Way We Use Technology Forever!”, I am now struggling to think of an alternative introduction to this article.

So, let me start by suggesting that the concept of bringing church services to the people is a concept that has been around long before Covid.  Indeed, it is an area of church worship that has been a relatively quick adopter of technology over many years.  Whether it is printed sermons, audio cassettes, DVDs or online platforms, the church has always had an interest in bringing the worship experience to individuals who are for one reason or another unable (or unwilling) to attend worship with their local community.  However, while there are good reasons for extending community worship beyond the four walls of a specific building at a specific time, isolation of individuals from the community of faith has been considered a bad thing, and by extension, providing tools that make it easy to isolate themselves from the community by providing a rationale that “I’ll catch-up the livestream so I’m not really missing out!”  This issue is perhaps food for another article for another time – arguably a Faith & Order matter rather than a technical matter but I have a foot in both those camps, so I don’t expect to escape.

However, for whatever reason, many churches are now trying to work out what they will do with the livestreaming setup they hastily put together in response to Covid lockdowns.  Over the next few issues, I will explore a few easy and (relatively) cheap ways to make your livestream experience memorable (for the right reasons!), starting with Audio quality.

Audio

Perhaps paradoxically, the best way to improve the technology side of a livestream – sorry, technology can’t improve the content – is to improve the audio quality.  The human brain can put up with an amazing amount of video defects so long as it has a clean, crisp and intelligible audio feed to help it fill in the deficiencies in the video.

A common strategy for first-time livestreamers is to rely on an in-built microphone in their camera device, whether a phone, webcam or even a more sophisticated camera.  The resulting sound from this type of audio setup is muddy because the microphone happily picks up every sound in the space, whether it is useful or not.  A single microphone in a space will make no distinction between sound reflected from walls, the kids playing at the back and the fire engine going past outside – it will capture everything it can hear.  If you are lucky, it will capture the preacher’s voice too.  If you are doubly lucky, the preacher will be louder than everything else put together, but there will always be some distortion as first the streaming equipment, and then the human ear, attempts to make sense of this very complex audio signal.

Ideally, we want microphones that are placed as close to the speaker (human speaker, not technology speaker) as possible, and optimised to reject as much background noise as possible.  Which, un-coincidentally, is exactly what you should be trying to achieve with a church sound system.  If your church already has a sound system, the easiest way to improve your livestream sound is to use the sound system’s sound.  Stream the video from the camera(s) and the audio from the sound system together and you should see (sorry, hear) immediate improvements.

There are a couple of caveats to this approach;

  • If your church relies on congregational singing, or has lots of responses in its worship liturgy, or other non-electronic audio that is an integral part of the livestream, then you will probably need to add some microphones to capture that audio.  However, you probably don’t want that sound to come out of the local audio speakers – to do so would be to invite instant feedback (and the ire of the now deafened congregation).  This means that your sound system needs to be able to support multiple outputs or buses and has the ability to switch specific inputs to only specific outputs.
  • Similarly, if you have someone in your livestream audience who is going to speak (for example, if you are using Zoom Meetings), the sound that originates from Zoom should never be sent back to Zoom – this time the feedback (and the ire) will be in the Zoom Room.  The solution is the same – your sound system needs to support multiple outputs and the ability to switch inputs to specific outputs.

So, give it a go and see how much better you can make your Livestream sound.

Next time, we will look at Lighting.

Peter Lane is Principal Consultant at System Design & Communication Services and has over 30 years of experience with Technology systems.  We invite your questions, suggestions and ideas for articles.  These can be submitted either through the editor or by email to dct@dct.org.nz.  We also operate a website focused on building a community of people interested in improving how we can use technology in churches, located at www.dct.org.nz

Peter Lane

What Was That? – Hearing Augmentation Systems

Posted on by Peter Lane

As I found while researching this article, the statutory requirements relating to Hearing Augmentation Systems (sometimes referred to as Hearing Assistance Systems, or Listening Systems) in NZ buildings are Convoluted, Confusing and Contradictory.  But I knew that – that was why I thought it would be a good topic for this column; I still wasn’t prepared for how much CC&C there actually is!

And to make it worse, compliance is signed off at the individual Territorial Authority level, and the interpretation of what is deemed to comply varies from Authority to Authority; sometimes from Building Surveyor to Building Surveyor.

Hearing Augmentation Systems are systems put in place to allow aural information to be conveyed to Building Users clearly and accurately.  The Building Act and NZS4121 (Design for access and mobility – Buildings and associated facilities) are clear that the scope includes users who don’t require hearing aids; however, the Building Code clearly states the requirement is only for persons requiring hearing aids (G5.3.5).  The guidance that is given in these documents and other related materials is that the Building Code is the minimum standard and the expectation is that an adequate solution will be designed for a given space, taking into consideration the requirements of the particular location and function of the space.  There is also a requirement that Hearing Augmentation systems are maintained 6-monthly.  In theory, they should appear on a building’s compliance schedule and are part of the Building WOF process.  Also, because they are disability systems, the building must have prescribed signage.

Hearing Augmentation technology and Hearing Aid technology are both in the middle of the technological revolution – both are adopting “new” digital techniques and methods to implement the required functionality and feature set.  Hearing Aids, in particular, are adopting new technologies rapidly such as linking to a user’s smartphone.  The drive for miniaturisation, however, means that Hearing Aid manufacturers are increasingly leaving out the T-coil which has been the basis for Building Hearing Augmentation systems since the 1960s.  The next 10-years will be interesting as the new technologies are trialled and adopted, and transition through the hearing aid population.  Hopefully, it won’t take the legislation too long to catch up.

Hearing Augmentation Systems

So, what types of Hearing Augmentation systems are there?

Sound Capture

Firstly, all Hearing Augmentation systems require a system of microphones or other audio input.  This can be built into the system itself or can be acquired via a sound system.  In some circumstances, this means the sound system needs to be left on even though it is not needed in its own right.

Audio-Frequency Induction Loop Systems (Hearing Loops)

These loops are usually installed in meeting rooms or in other places where people gather.  They assist people who have hearing aids fitted with a T-switch.  They can also assist people without hearing aids if the user is provided with a loop receiver device.

In addition to permanently installed hearing loops, there are portable hearing loops available.  These can be used in small spaces such as meeting rooms or motor vehicles.  Loops are sensitive to building construction and other wireless frequency emitters (including other Hearing Loops, so they are not good in multi-room environments).

Infrared Systems

Infrared systems take the sound input signal and broadcast it on an Infrared frequency within the space, which is then picked up with a system-specific receiver worn by the user.  These systems generally require a direct, unblocked, line-of-sight to the user and require users to obtain and wear a receiver with the appropriate attachment.  They can be used by users without hearing aids.  They are sensitive to very bright lights and sunlight and the receiver unit must be worn outside clothing etc.

Building operators need to keep a supply of receivers, batteries and headphones forbuilding users to use as required.  Headphones or in-ear devices are subject to Public Health cleaning requirements.

FM Wireless Systems

Structurally, these are very similar to Infrared systems but use FM radio frequencies rather than Infrared frequencies.  Consequently, they are not limited to direct line-of-sight.  Receivers can consequently be put in a pocket or handbag with relatively minor impact to performance.  While they are not impacted by sunlight, they can be affected by other wireless emitters.

There may be some old wireless systems around that use VHF radio frequencies.  Given the recent changes in frequency allocation in favour of mobile phone service providers, continued use of this band is problematic.

Peter Lane is Principal Consultant at System Design & Communication Services and has over 30-years’ experience with Technology systems.  We invite your questions, suggestions and ideas for articles.  These can be submitted either through the editor or by email to dct@dct.org.nz.  We also operate a website focused on building a community of people who are interested in improving the way we can use technology located at www.dct.org.nz.

Peter Lane

Radio Spectrum: Accessibility or Entertainment?

Posted on by Peter Lane

Radio Spectrum Management have been circulating a consultation and discussion document, “Preparing for 5G in New Zealand – Technical Consultation”.  The “gotcha” in the fine print is that one option being considered is to move the IMT Band (Industrial & Medical Telemetry Band) as well as make some provision for 5G into the 600MHz Band.

That is the band that most churches who have just bought new wireless microphones will now occupy, having been pushed out of the 700MHz band a couple of years ago.

My company has made the following response to the Radio Spectrum Management discussion document.  It is based on a proforma response originating with WUNZ (Wireless Users NZ), but I hope I have managed to value add the thought that there is more to life, and value, than entertainment and sports events and that some of the people impacted by “minor” tinkering with the spectrum are the ones with least capacity to pay for the consequences, but who provide valuable services to society at large.

The discussion paper can be found here – https://www.rsm.govt.nz/projects-auctions/current-projects/preparing-for-5g-in-new-zealand-technical-consultation

Response: Preparing for 5G in NZ

From System Design & Communication Services.

This response relates particularly to the Discussion Document questions 1, 15 and 16. 

As a current user and supplier of radio microphones and in-ear monitors that operate in the 600MHz band, I would be an affected party if this frequency band is reallocated for IMT/5G usage.

Radio microphone users would lose 76MHz of nationally available spectrum from this 600MHz band. Currently, there are no other spectrum bands that appear to offer this same amount of spectrum as a contiguous available block nationally throughout New Zealand.

As a specialist supplier to the non-profit and religious sector, I would point out that this sector, in particular, is ill-equipped to make another forced “fork-lift upgrade”, and the response of many of my clients will be simply to do without such systems.  The immediate consequence of this will be an immediate degradation of service to the many hearing-impaired and disadvantaged persons to whom my clients provide social welfare services (and in extreme cases may even lead to cessation of service provision entirely). 

At another level, removing capacity to operate relevant equipment in the 600MHz range may cause some of my clients to lose their ability to comply with their obligations under the Building Code and Disabilities Code.  Compliance with these may involve providing Hearing Augmentation systems and the audio source for such systems will be a microphone.  In many cases, the functional and logistic requirements of the service being delivered dictate that this microphone should be a wireless device.  Loss of 600MHz systems may require not only replacement or modification of the microphone but may require replacement and/or modification of the entire Hearing Augmentation system, possibly requiring extensive associated building works.

The benefit of such social and potentially intangible services provided by the non-profit sector is not as easy to quantify as the glamour entertainment sectors of Music, Sport and the Arts.  However, the social and economic benefits of the sector are not inconsequential.

I request on behalf of my non-profit clients, that Radio Spectrum Management adopt the following recommendation as a guiding principle of re-planning NZ spectrum;

  • Ensure that sufficient usable spectrum, preferably in the existing 600MHz band, is preserved for radio microphone and in-ear monitor usage at the community level for educational, health-related and social good purposes by non-profit and religious entities.

I also request that Radio Spectrum Management carefully consider these comments and the following recommendations should you resolve to reallocate the 600MHz band and therefore require current radio microphone and in-ear monitor users to re-acquire or modify existing hardware to alternative frequency bands.

  • Provide monetary compensation to affected users who acquired or modified hardware in direct response to the 700MHz spectrum sell-off.

Ensure that sufficient usable spectrum is preserved for radio microphone and in-ear monitor use at large scale events, such as concerts, festivals, theatre productions, red carpet movie premiers, and sporting events.  This provision should make allowance for the fact that multiple users and/or suppliers are operating concurrently at some of these events types.

Peter Lane

A quick guide to using microphones effectively; a presenter’s perspective

Posted on by Peter Lane

A lot of us never need to get behind the business end of a microphone. But for those who have to present regularly, it is important to have a basic understanding of how different microphones work. Then we are able to adapt our speaking technique to suit the microphone in front of us as we deliver our message. This is a quick guide to using microphones effectively for presenters of all ages!

Microphones are components in virtually all audio systems.

Thus, you’ll hear about studio microphones for recording and PA microphones for live sound. There are boom microphones for broadcast or film shoots.  Or instrument microphones which attach directly to guitars or other musical instruments.  Then there are boundary microphones or boundary effect microphones for theatre work or conference systems, lapel mics for seminars and business meetings, and headset microphones for telephone call centres. (And this is just to mention a few options). The different types of microphones optimise a range of different requirements in different environments.

That said, all microphones have one thing in common: “microphones convert a sound wave into an electrical signal in which the voltage and current are proportional to the original sound”.  To perform this task microphones use a thin membrane, known as a diaphragm, which mimics the function of the human eardrum.  Sound waves strike a microphone’s diaphragm and cause the diaphram to move. Harnessing this movement creates an electrical signal.

A sound is essentially a change in pressure that varies in specific ways over time to create specific sounds (sound waves).  When sound waves strike a microphone’s diaphragm, they cause it to move, which movement, in turn, creates a variance in an electrical current (aka signal).  The electrical signal is transmitted to output devices, which either process the electrical signal (store it, or make it louder, or make it sound like Darth Vader on a bad hair day), or use the signal to recreate sound waves (loudspeakers).

Microphone Types

Microphone engineers, over the course of “recorded” history, have developed 3 fundamental techniques for detecting sound waves and “transducing” sound to electrical signals. 

Dynamic Microphones

A dynamic microphone uses the diaphragm to move a coil of wire within a magnetic field to create the electric signal.  It’s advantages are it’s relative simplicity and good voice frequency characteristics.  A dynamic microphone is quite sensitive to interference from external electromagnetic fields. If your venue has a hearing aid loop, you don’t want to try dynamic microphones. 

Condensor Microphones

A condenser microphone uses the diaphragm to move one side of a capacitor plate thus causing the capacitance to vary. This creates an electric signal.  The advantages are it has good resiliency, can cope with large variances in the sound loudness and tends to have a larger frequency response.  Condensor microphones are often used for instrument microphones, however, are the basis for many vocal microphones as well.  The disadvantage is that the capacitor requires a power source to keep it charged. Therefore, a condenser microphones require either batteries or a power supply delivered from the connected equipment. 

Ribbon Microphones

Ribbon microphones consist of a thin strip of metallic foil suspended in front of a magnetic plate.  Sound waves cause the foil to vibrate, producing fluctuations in the electrical current, creating the audio signal.  This extremely sensitive configuration picks up a wide range of frequencies and produces an extraordinarily rich representation of the original sound.  The trade-off for this sensitivity is the delicacy of the mechanism – ribbon microphones are very sensitive to physical impacts and power overdrive.  (Oh, and very expensive).

System Engineering

The other factor that effects using microphones is the system engineering.  A system engineered for voice reinforcement usually uses rather sensitive microphones and try to “hide” the microphones away so they don’t distract from the presenter.  A vocal microphone for a rock band vocalist, by contrast, can have much lower sensitivity. In this case, however, the microphone is held within millimetres of the vocalist’s mouth. This means that the microphone “hears” only the voice and not the other instruments around it. 

Principles for Presenters

So, as a speaker/presenter, how do you make sure you are heard and understood?

  • Learn to recognise – or at least be able to take a good guess – at what internal configuration and pick-up pattern the microphone has.  If you have the opportunity to research beforehand, do so.  Then adjust your speech style accordingly – speak “firmly” to dynamic microphones, but more relaxed and rounded to condenser microphones.
  • When you have a sound operator, work in cooperation with them. A good sound operator will usually have a better understanding of the capabilities of the microphones they can offer.
  • While standing normally, move the microphone so you are “looking down the barrel” of the microphone.  If you can’t move the mic, move yourself.  For guidance in using voice reinforcement systems, a hand-held microphone should be about a handspan from your mouth.  Stand-mounted or Lectern mics should be about 15”/400mm away from your mouth.  A microphone on a stand will typically be setup for voice reinforcement. Taking the microphone off its stand and useing it as a hand-held will result in excessively loud sound-levels. A good sound operator can help here. However, don’t assume they can read minds, so try to give them some warning what you intend to do.
  • Ensure your voice production is clear and controlled.  The microphone doesn’t make the sound for you – it reinforces the sound you make.  If the sound you make is muddy, mumbled and unclear, so will be the amplified sound.
  • Watch your dynamic control.  By all means express yourself dramatically – just stay within the bounds of the system capability. If all your drama only bursts your audience’s ear drums, they won’t “hear” anything else. In either sense of the word.
  • Watch you don’t move off orientation to the microphone. It’s fine to walk around if you are comfortable with that – so long as the microphone walks with you and stays properly oriented to your mouth.  (If you are able, use a wireless microphone such as a lavaliere clipon, developed specifically to address this issue. However, they still need care to setup and use.)  Some microphones are more tolerant than others, but just turning your head can make a big difference.

You speak to deliver a message – don’t let the technology become a distraction to that message.

Peter Lane

Enabling Inclusion

Posted on by Peter Lane

Bringing Church to the people (or People to the church)

I believe it is fair to say that the original motivation for a lot of church sound systems was the capability to record services to cassette, which could then be distributed to the housebound, the ill and others who might be interested.  As a social mechanism for inclusion of community members who may otherwise be marginalised, it is a practice of considerable merit (although I suspect that you had to physically deliver a cassette tape in person might be a contributing contributor to this).  Cassette tapes have died the death of technological obsolescence, but there are still churches who effectively continue these principles with equivalent modern technologies.

So, it was of interest to me to come across a Facebook post from a person asking to for advice on how to use technology to flip this idea on its head.  Rather than asking how can we share what we do in worship with those who can’t be present; but instead, how can we assist those who can’t be present to contribute to and participate in what we do in worship.  So, this being a technology column, let’s look at some ways to do this.

Technologically, we can categorise suitable methods as audio-only vs audio-video, or as pre-recorded vs “live”.  There are many options available, but the solutions I indicate below are based on real situations and products I know work – this is not to suggest there are no other ways this can be done.  I’ve assumed that your playback location has a sound system built-in, and a projector or video display for video, but there is no requirement for this – there are portable solutions available at low or moderate cost if required, provided care is taken to consider the requirements inherent in the size of the venue.

Pre-recorded audio-only and audio-video

This is potentially the simplest way to start including others.  There are many devices now to record digital audio – a smartphone usually being the easiest to get hold of.  Place the device on a solid surface or tripod if you can in front of the person speaking – resist the urge to hold it in your hand – and use a recording app.  The built-in one will usually be fine, but there are lots of options, both paid and free.  For video recordings, make sure the subject is well lit, particularly the face.  Place the camera lens at the same level as the subject’s face and remember that for speech, close-ups are more effective than long shots (especially when relying on built-in microphones).  Sometimes, the easiest way to capture audio for audio-only play back is to make a video recording.

Having made your recording, the recording file needs to be transferred to the playback device, usually a computer.  If you must remove that unfortunate moment when the fire engine went past, use editing software to trim to suit.  Audacity is a good free program for this for audio, and I tend to use VLC for video.  I also use Camtasia but it comes at a cost.  Also, NCH have a range of good audio and video programs on a free-to-try basis, with very reasonable pricing if you decide you like it.  Depending on your final playback platform you may need to convert the file from the recorded format to a format compatible for your playback system – most editing programs allow at least some degree of format conversion, but there are also dedicated conversion programs available.  Often, embedding the audio or video in a power-point slide is the easiest way

Live audio-only and audio-video

The principles of capturing a recording is fundamentally the same as for Pre-recorded – you just won’t have the opportunity to do any editing or format conversion – get it right first time!  You will need to have some form of reasonable network connection to your venue though.  Packages include Skype or Zoom.  Livestream.com (as used for recent conferences) is also a moderately priced option.  Essentially, you use the solution to “make a phone call” from the reader to the venue.  This can be answered directly, but a slightly more elegant solution would be to provide a video-switcher at the venue so that the call can be placed and/or answered and everything made ready before the call is displayed to the audience.

I’d love to hear about what you are doing.

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