Room Acoustics – Are You Sure That Your Acoustics Are Really Bad?

Room Acoustics

When we get involved in projects to renovate auditoriums lecture halls or classrooms, one of the common complaints we hear from people is “we have bad acoustics.”

Now that statement can have a whole plethora of meanings. So, we start probing. “What exactly do you mean by ‘bad acoustics?’”

As you can imagine, the answers we get back are all over the place. Some people think their room is too live. Some people think their room is too dead. Same room! Some people think that the room has zero sound quality. There is no consistency in what people call “bad acoustics.”

There are rooms that in our expert opinion sound quite good while, in the client’s opinion, the sound quality is bad. There also are rooms that we think sound absolutely awful, but people love them.

Here is a good example: We visited a church that has an exceptionally long reverb time in the main sanctuary – way too long for the spoken word, way too long for any kind of contemporary music – yet, the members just love their acoustics. Reverb time in that room was two and a half seconds in the mid-band, which is really excessive.

The reason they love the acoustics is that they have a choral group and a big pipe organ. For that purpose, the room sounds surprisingly good with a big full sound.

It was just that the listeners were not be able to distinguish the words that the choral group was singing. That, apparently, was not a priority for them. They were happy with it just the way it was.

They wanted better spoken word, but they would not sacrifice any reverberation to obtain it. They wanted a sound system to fix it all.

We have been in other venues where the clients say they “like the acoustics,” yet the room is dead as a door-nail. Often, in those cases, the reason that they like the acoustics is that the primary use for the room is for something like lectures.

However, when they stage a musical event in that same room, it is dull sounding. That is why, when people first say they “like” their acoustics, we ask more questions. Until we know more, we cannot really trust that we know what they really mean.

So, the concept of “good” acoustics is not a standard. There are a lot of standards in the acoustical industry defining what appropriate acoustics are, but for specific uses. A room with good metrics may not be perceived as “good” at all. This is especially true when you get into multipurpose rooms that have more than one function. When the rock band gets booked into the opera house, bad things follow.

Whose Fault Is It, Anyway?

Another real misplacement of blame happens when people add to their “bad acoustics” complaints a discussion about their sound engineer. What they are really talking about is the person running it. But the problem may not be the sound engineer at all. It just could be the performance of the sound system. Or, it could even be both. Obviously, the sound engineer is the final determiner of outcome in any space where sound is being mixed but the outcome will only be as good as the design of the system, and how it works with the room acoustics.

Sound systems must be designed to work with the room acoustics, not against them. Over the years we have seen many sound systems that seem to have been designed completely ignoring basic physics, the layout of the room, the reverb time of the room, the reflections and echoes in the room. Hate to say it but they “slapped something in there” with little thought.

Is the only “good seat” where the sound guy sits?

Sometimes the “good seat” is where the sound guy sits. So, you have a sound guy who is sitting in a location mixing and he thinks he is doing a good job, but the sound he hears is completely different than the sound in the rest of the room.

So, back to the initial complaint, there are a number of things people are not understanding.

The sound engineer needs to be located where he/she actually can hear an average (ideally) of what everybody else is hearing. Or they have to learn how to translate what they hear where they are.
The sound system has to be designed to work with the room’s acoustics.*

*Some sound system companies, the ones that just put in speakers and install equipment without doing any kind of analysis, are not skilled enough at placing loudspeakers and tuning a sound system to get it to work well. In these situations, the sound engineer may not be the one at fault.

So, after speaking for a while with our clients about the difficulty they are having, we arrive to an understanding that…

There is no one room condition that is going to make them happy.
There is not a different sound system that is necessarily going to make them happy.
It is not all the sound engineer’s fault.

…now we can talk about some real solutions.

How do we make a bad sound situation better?

When we design physical acoustics using diffusors, absorbers, reflectors, and various types of structures to guide the way that sound behaves in the room, there are limits to what can be done.

Often, there are budgetary restrictions to what can be done.

Some of the things that might work really well acoustically could be extremely costly. The cheaper ways of adjusting a room acoustically can be kind of ugly. They can look more like you have just randomly attached a bunch of things to surfaces instead of designing a space when you are doing a renovation.

STEREO

So, it can be challenging. First, you must decide what the goal is. What is the room designed for? Speech? Choral? Orchestra? Contemporary music? When you do adjust physical acoustics, you end up with one condition and that condition is the way everything renders in the room. Remember that rock band in the opera hall? …… Not a good option. Better to find some middle ground.

When it comes to the sound system, there are similar decisions to be made. Certain aspects of sound systems design conflict with others.

The idea of left and right is wonderful if you are sitting in the center of the room. Anybody sitting in any seat other than the center line will only hear some of what is on a side of the stereo pair if the sound is panned left or panned right.

If you go with a center cluster, it can be very intelligible and sound great for speech, just as long as it covers all the seats.

There are a couple of problems with using center clusters, however. One is that they are mono and one dimensional, lacking any sense of breadth. Ears hear energy from both sides of the head and the way that energy arrives to your ears gives a sense of warmth, a sense of being enveloped by the sound, which is an important part of the experience. Center clusters tend to be dry sounding. They can be very intelligible but not very musical.

Then you move up to left – center – right, which is a commonly talked about concept that most people do not really understand. In a left – center – right with stereo capability you have to maintain panning consistency so that when something is panned to the left, the entire room still hears the sound and it is perceived as coming from the left.

If your room is wide enough, which most are, there is a time delay problem with trying to send sound from the far left side of the room to the far right side of the room when the far right side of the room has loudspeakers arriving much earlier. So, the way you manage this is your center system ends up having multiple elements and becomes part of the left and part of the right with time delays applied to correct for offsets distances.

In some rooms this arrangement can work fairly well, but the setup and tuning of a system that is true left – center – right with stereo capability is not only complex but more expensive because you practically triple the number of elements required to accomplish the goal. Consequently, what most people tend to do, at least for sound systems in multipurpose rooms is a left – right system that is actually mixed as dual mono.

Comb Filtering and the Haas Effect

Most of the time you never really pan anything full left or full right, correct? You have to have both systems creating the same signal which, inevitably, will cause some phase problems. Depending on where you are sitting you will be hearing both sides of the system somewhat out of phase with each other. The effect that occurs is called “comb filtering.” When that happens, if it is done poorly the room can sound muddy.

So, it requires a lot of skill in placement of those loudspeakers. You must look at time delays to various seats in the room while trying to maintain something known as the “Haas Effect.”

The Haas Effect has to do with the arrival time of energy from two locations to a particular seat. If you are within the Haas Effect, (which various people disagree about whether it is 30 milliseconds or 50 milliseconds) the sound can still be good, even though it is coming from two locations from the same sound source. Once you get outside of the Haas Effect timing, a lot of destructive things happen, quite audibly.

This is all a simplified explanation there is a lot more going on……

So, this is the first segment regarding the basics of room acoustics/ sound systems.

Want some supplemental reading? Go to => Auditorium Acoustic Options

Video Conferencing Services

With a new emphasis on streaming and online meetings, many people are discovering the many pitfalls of remote technology.

Whether it is an online worship service where you can only hear half of what you see, or an online conference meeting with audio and video issues, when things don’t work, it’s a problem.

And now that we have virtual classrooms where the teacher meets with students via an online platform, quality control is essential. AVL Designs Inc. is skilled in all the subsets required for successful remote communication: Acoustics, Audio, AV, Lighting and Video.

Let us help you create a great remote experience.

RDM – Remote Device Management

RDM – The LED Conundrum Part 2

Let’s talk a little bit about RDM. RDM (remote device management or remote duck management) is a way to remotely change settings on DMX/RDM lighting fixtures.

In case you missed the first installment of this series : The LED Conundrum Part 1

What you are supposed to be able to do is to plug a lighting fixture into a DMX/RDM certified network and have the lighting console identify “Oh, that’s this kind of lighting fixture. It requires this many DMX channels and is currently addressed to this DMX starting address.”  You then would be able to remotely change that and other information.

You are supposed to be able to remotely change the mode the fixture is running in, so if it was running in RGBW and you want it to be running in some other mode,  you should be able to remotely change that. You are supposed to be able to remotely change the DMX starting address. (Can you tell that this “supposed to” treatise is leading somewhere…..)

Yes, you are supposed to be able to remotely change other factors, too, like special effects and things within the fixture.

When you take a company that is, let’s say, probably the largest console manufacturer in the world in the lighting industry and their DMX implementation is reportedly compliant to the standard, and you hook the fixture up to the system,  it is supposed to respond with  “Hey, hi there fixture. What are you, what are your parameters? I want to change your starting address. Let me do that.”  

That superb console manufacturer is what we use as a standards reference.  We find that some manufacturers’ fixtures just don’t show up or if they do show up, they don’t show up with all the correct information or they show up with some of the information but don’t let you change it.

So, here are just a couple of examples of what we ran into when we hooked up a fixture to one of these consoles.

The fixtures shows up and it says to the console “Oh, that’s an LED fixture. It’s operating in 16 bit mode, starting on address 10 and it requires 17 channels, whatever it was.”  What kind of fixture? “Unknown.” It really didn’t work properly.

So, I went into my console library and found the fixture since I actually knew what it was and the system wasn’t telling me. It said, “it is a fixture that does this stuff” and once I pulled down its profile, it worked fine. However, it would not allow me to change it. Can’t change start address, I can’t change it from 16 bit mode to 8 bit mode, et cetera.

With other fixtures  that I’ve tried from various manufacturers, some of the data did not show up at all. Some of them show up with random issues when you try to RDM search or flash them on a network, all kinds of problems. (Let’s not even talk about house lighting manufacturers where you put everything on a network and nothing works. Talk about a disappointment.)

So RDM is an interesting theory, if the devices out there were truly compliant.  So RDM obviously can send the data back and forth. The problem is that a lot of people are not fully implementing it and are not sure why.

We don’t have access to every console on the market so there always is the possibility, since I’m not a real like digital protocol wizard, that some manufacturers have certain data packets that they have designed to only send to their own stuff.  If that were the case it would seem to be a very shortsighted way of doing things.

If there is anybody out there who knows more about this, I’d be curious to hear your take on it. I have had many  talks with that really big lighting manufacturer to find out if they have any ideas, too. In the past when I have talked to them about it they’ve said, “Nope, we’re not trying to block out anybody else’s stuff. Their product just doesn’t work properly.”

Bottomline, for someone who needs to use RDM, it can be a nightmare. Let me give you a picture of what you could run into.

HOUSELIGHTS

Let’s just say you put up a new building and there are a hundred house lights and they are all DMX/RDM (supposedly). And the electrical contractor you hired didn’t check the firmware version, didn’t test the fixtures, didn’t do anything which he was required to do under the specifications before he put the fixtures in the ceiling. You come in and try to find the fixtures using RDM and you find that, let’s say 50% of them don’t respond.

So the question becomes, are 50% of them defective or are they just not set up properly? Now you have to battle through that. Sometimes you have to crawl into the ceiling, which can be fun if the ceiling isn’t something you’re able to crawl into, and manually find a way to address these fixtures.  

This usually means taking them off the network and using a handheld controller, which often with a single fixture, when that controller is available from the manufacturer, will let you address their fixture.

Sorry to say it but that is what you may have to do. Maybe their fixture isn’t even designed to work with the world of entertainment lighting and is only designed to work with their handheld plugin. Not such a good thing. Our recommendation for house lighting is to make everybody address every single fixture and test it before it ever goes into the ceiling. It is extra work for the electrical contractor, but you can see that the alternative can be a nightmare. Testing first is much less work than taking the ceiling apart later.

THEATER FIXTURES

Now, let’s just say, on that same system, you’ve got say a hundred theater lights form  three manufacturers and they’re all supposed to be RDM/DMX. Now, when you plug them all into your data network and you start looking for them, only some of them show up telling you what they are and how they’re addressed.  Hopefully, some of those you can actually remotely fix. Wonderful. But then you discover that a lot of the other ones, which are from different manufacturers, tell you nothing at all.  

Now you will have to manually address those, physically get to the fixture, get to the menu, set it up and address it. Then find a library profile for it to work.

That gets you going but in  the future, if somebody wanted to remotely change the setup because of the way they want to run a show, it is not possible. You are stuck.

One of the key things to know is that if someone’s going to end up with a system where they cannot remotely address certain fixtures, they must be made aware of that in advance.

One thing we recommend highly, (even though in the professional world this would seem odd), is to physically mark the original DMX address and DMX universe on every single fixture. Labeling them will tell the user that, “Oh, this fixture was on universe one channel 250 when it was originally installed, which means if I just plugged it into universe 2 it is not going to work.

If I plug it into universe 1 and I’m trying to call it up on channel 300,  that also is not going to work.” And they’re going to have to manually readdress that fixture. Also mark on the fixture “does not RDM” so they know to set it first before use.

Sometimes you just have to mix products and, unfortunately, the end user is left dealing with the problem, but they need to be made aware. In the public bid market, there is often the “or equal” clause.

So when a fixture says on paper that it is RDM, you are expected to believe that. Sadly, there are times that it turns out to be completely not true. At other times, it turns out to be partially true. Some of those problems are really hard to address because they are not consistent.

My advice: buyer beware. Test before you buy.

We do.

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Newfield High School

Newfield High School

Newfield High School’s auditorium was an outdated facility housing a very active theater group. In fact, people at the highest levels of the school administration have contacts who work in theatrical productions in New York city. Those pros come in to operate shows at New Field High School.

Newfield High School needed an update!

AVL Designs Inc. was contracted to design new stage rigging, lighting, audio, video, and make room acoustic corrections for the auditorium. The architect was tasked with raising the height of the fly space to make it more usable for productions, as well as adding a balcony and enlarging the entire seating area of the auditorium.

Large video screen in the Newfield High School Auditorium - part of the renovation design completed by AVL Designs Inc.

The resulting changes to the room are striking, not only visually but functionally as extensive system improvements have been made.

Control boards for the sound, lighting and video at Newfield High School auditorium

Lighting has been enhanced with LED lighting fixtures as well as additional moving heads. The new audio system is a dramatic improvement. It includes an Allen & Heath D live digital console, expanded wireless microphone inventory, a new sound system Mains, subwoofers, over and under balcony fills and stage monitoring are included.

Theatrical renovations were made at Newfield High School.

An electronic stage orchestra shell was added to enhance sound on stage as well as in the house using proscenium loudspeakers to expand the coverage of the electronic shell into the seating area.

The stage fly space was raised in height and all new counterweight rigging was designed using brick house technology. Although a FOH catwalk is part of the project, it could not be properly located to provide good lighting positions to the pit area. A motorized FOH batten was included just below the catwalks. This batten is populated with moving heads, allowing flexible for forestage lighting.

The new video system is a utilizes an HD laser projector with Crestron controls. Projection is made to a 298” diagonal screen. An HD PT Camera provides video feeds to green rooms and streaming.

Note: Unfortunately, due to the COVID-19 problem, their first show was canceled. As a result, photos of the room were taken with the disarray of an abandoned building, being evident in all of the photos. The cast and crew were told to “leave the building and don’t come back” and they hastily left everything behind, just as it was during their show prep and rehearsals. We hope to get better photos of the room when all of this subsides.

Video Conferencing

Video Conferencing – STAY OFF THE SEESAW

At a time where video conferencing is way up, awareness of the need for technical quality in those online meetings has also increased.

Given a choice, many people would rather not meet online. But when there is no choice, why not reduce frustration and make it a more enjoyable experience?

Today, I simply want to address how to make online meetings sound better.

Video conferencing tips to help your online meetings sound great!

This afternoon I was sitting through yet another online conference and listening to relatively horrible audio.

The primary factor causing the audio to be so irritating was a lack of understanding on the part of participants. They just didn’t get how the audio component in video conferencing software actually works. When you think about it, why should they?

Here is a brief explanation of how things work in the app-based “Video Conference World” that should help.

“One at a time?”

Video conferencing software is set up for one person to talk at a time. It is not a party line situation, like it would be in a real conference room where anyone can talk at the same time and still hear others who are talking.

These online systems are set up to feature just one person talking at a time.

And, of course, that is a problem. When you are in a video conference room, the tell-signs of who is about to say something are just not there.

Get off the seesaw.

Video conferencing kind of works like a seesaw. Only one person can be at the top. The other person must be at the bottom. One person talks, the others listen.

Going back to our video meeting scenario, something happens at the in-between as the next person speaks up. At that in-between moment, each person is reduced in volume for the system to transfer from one to the other.

Video conferencing from home has its challenges. Barking dogs, background noises, doorbell unexpectedly ringing... things happen! This little dog wants to get in on the show!

To add to it, even if only one person is talking, should an unplanned noise occur in the room – rustling papers, dogs barking, etc. – the software will think someone is talking and will take the volume from the true orator and try to give it to Fido.

Background noise is certainly one of the reasons they added a mute button to the software in the first place. When people leave their microphones un-muted, any little noise, whether it is their own breathing, the whir of an air conditioner, or a knock at the door, makes the system think that you are taking over. The featured person who was talking suddenly is reduced in volume while the system tries to decide if you are going to continue or if you are going to stop.

If the noise interference ceases, the software raises the level back up so that the person who was really talking can be heard again. How often have you been in an online meeting when sound interference occurred? That is when people in the meeting will chime in “Can’t hear. Will you say that again?” We have all been there, haven’t we?

Push to Talk

The solution to this audio problem is to use your mute button a lot. Most conferencing software has a “push to talk” mute capability built in. In the better systems, if you mute your microphone with your mouse, the space bar of your computer then becomes a push to talk button.

When you press the space bar, it will temporarily unmute you while you talk. As soon as you let the space bar up, it will mute your microphone again. So, for the sake of all of us out here, please use the bar and mute your microphones when you are not talking.

Friendly note to the conference administrators: each time you start a new meeting, remind the participants to mute themselves and that they can “push to talk” when they want to speak. Your meetings will flow more smoothly.

Why is there an Echo?

Why do we hear an echo? An echo is the result of someone talking, then the sound goes to the far end (delayed) and is played back through a speaker. The speaker output at that end gets picked up by the microphone on the other end and is repeated back and forth. It is audio ping-pong. So, how do we get it to stop?

Echo cancellation software is in the app and it makes a one-on-one situation work well, but if everyone has their mics open and speaker volumes turned up loud, there are just too many sound sources for the app to always fix.

When your mic is muted you will eliminate echoing because echoes do not occur when just one person is talking. In other words, if every meeting participant remembers to mute their mic, using the bar when it is time to speak, echoes will be almost non-existent.

But what if you cannot unmute? If muting is not possible then reduce the volume of the loudspeaker on your device or use headphones so that extraneous sound will not be produced and picked up by the speakers.

The bottom-line is that each video conferencing system, be it Zoom, WebEx, StarLeaf, Google Meet and the like, has varying degrees of audio quality but none of them can fix errors that are created by the users.

Only you can prevent bad conferencing!

AVL Designs Inc. Featured on ProSoundWeb

NY-Based AVL Designs Inc. Deploys Yamaha AFC On Numerous Projects Over Several Years

Acoutical designers and engineers at Ciminelli Recital Hall at Buffalo State University — Audio engineers working with performers in Ciminelli Recital Hall at Buffalo State.

Reprint from ProSoundWeb article April 23, 2020

Company principal/owner, Seth Waltz, reflects on the evolution and application of acoustic room conditioning technology on a range of projects.

Seth Waltz, a principal and owner of AVL Designs, a Penfield, NY-based firm specializing in A/V system design for performing arts, theater, worship, and several other applications, has worked closely with every version of Yamaha Active Field Control (AFC) acoustic room conditioning technology for more than 15 years.

He’s seen numerous changes in each of these applications, with traditionally high-end technologies being applied to smaller environments.

“Auditoriums with a few speakers and a microphone were once considered high-end A/V rooms,” he notes. “Now these same venues are being outfitted with million-dollar technology. The digital era has created a whole new mindset where a performing arts center, even at the school level, is looking for a higher level of everything: acoustics, sound quality, video quality and streaming. It’s all tied together.”

His first experience with AFC and its ability to configure and condition a space came in 2004 when he and his associate Geoff Nichols were invited by Yamaha to a system demo.

“We walked into what looked like a large office space with drop ceilings,” he explains. “A pianist backed by a string quartet performed for us with AFC applied to the room. If you closed your eyes, you would swear you were in a 500-seat theater. It sounded extremely natural. We got to play around with the system and we soon realized this is the future of room acoustics as far as having the ability to modify a facility as needed.”

AVL Designs Inc. first implemented the AFC system on a design project in 2005, turning a “plain Jane auditorium” into what sounded like a completely different sonic environment and drawing rave reviews from the project owner as well as the musicians who performed there.

Waltz points out that AFC technology has improved greatly over time, especially in terms of its processing and responsiveness. He’s also suggested new system developments such as an “orchestra shell”, allowing him to configure the stage as opposed to just the seating areas.

“With most of our jobs now, we’re simulating the performance of orchestra shells as well as covering the seating area and early reflections,” he says. “Now that the processors have become so powerful there’s no limit to what type of space AFC can fit. We don’t have to even think twice about metallic edging or other factors. It sounds so smooth that nobody seems to know it’s there.”

Waltz noted the only challenge to a successful AFC installation is a room with a high degree of mechanical noise, more common on projects that are updates to an existing space.

“You can’t have background noise or anything that creates echoes,” he said. “You won’t hear the nuances of the reverberation. Plus, the microphones pick up the noise and cycle it back through the system.”

Waltz looks forward to future versions of AFC incorporating new features and capabilities suited to a diverse range of applications. These include using the system as an effects device or controlling it via a mobile device. AFC4 can be controlled using the Yamaha ProVisionaire Control app on a PC or Windows tablet as well as ProVisionaire touch for iPad. These two software tools allow customers to create customer user interfaces to control various Yamaha equipment to simplify system operation for non-audio professionals.

Whatever changes are ahead for Active Field Control, Waltz is already confident in the technology’s ability to handle any project challenge. “Often at the tail end of a bid, someone changes the seating and suddenly the space is absorbing a sound we didn’t expect,” he concludes. “Or, something may happen during construction where you end up with different frequencies or there’s some other problem you wish you could do something about. AFC fills in the holes and helps compensate for these factors.

I tell clients, ‘I can give you one room that does one thing really well, or I can give you a room that does several different things well.’ Accomplishing this with physical construction alone is limiting, but AFC is extremely flexible and able to make one room do the job of many. It’s such a great tool.”

Yamaha Pro Audio

Author: AVLAdmin