Audio Production

Recording Magazinesends out a newsletter to its subscribers every few weeks. The newsletter is (coincidentally) titled “Sound Advice” and this month it features a new series on headphones and monitors. I asked permission to reprint this newsletter (and will ask to reprint the others in the series as well) so that those of you with home studios can also benefit from the information. I want to personally thank Brent Heintz, VP/Associate Publisher for granting permission, allowing me to share this great information with you.

Please visit Recording Magazine‘s website and their Facebook Page.

Voiceover usually deals with a singular signal (your voice) and therefore it is typically mono. However, the importance of space and spatial recognition cannot be overstated. By their very nature, how you hear headphones and monitors greatly effects how you hear yourself and your ability to interpret what you hear.

So… please enjoy this installment from Recording Magazine’s Sound Advice on Acoustics.

Welcome back to Sound Advice on Acoustics! We’ve been discussing how to use headphones as critical listening monitors, but author Robert Auld warned us way back at the start that his answer to “Can we do it?” is “Yes, but.” In this month’s installment, it’s time to look at a really big ‘but’, if you’ll excuse the expression…

***

I said that my ‘yes’ to using headphones as critical monitors was qualified. Jerry Bruck explains one small but important problem that can happen when editing stereo program material:

“I love using headphones for editing because of the precision. If there’s some vestige of something you don’t want in a splice that’s, say, coming in or going out, the headphones will nail it in a way that loudspeakers never do.

“But—and this is a big but—a real danger exists, because I have many times had the experience, as others have had, of making a splice in music, and on headphones it is totally inaudible. You sit there congratulating yourself on what a wonderful splice you have just made, and then take the headphones off and turn up the speakers, and suddenly it’s glaring. It’s there, and you can hear it, and you go, ‘How can that be? Why can I hear it on speakers and not on headphones?’

“I don’t really have an explanation, but I will venture one: that it has to do with the phase relationships between the channels. Again, it’s the interaural mixture that occurs with speakers and doesn’t occur with headphones. Once that happens the two channels have phase relationships that are a giveaway that something has happened here that could never happen in real life.”

“So I would more than caution anyone, I would actually warn anyone who attempts editing in headphones: check your work on speakers. It doesn’t happen every time; it happens like one time out of twenty… but that one time will really amaze you when it occurs, and you’ll have to go back and redo it. Otherwise everyone is going to hear it.”

A good case can be made for always using both headphones and loudspeakers to monitor our work. The two different monitoring methods each tell us different, useful things—stuff that we really need to know. (There is also the issue of the increasing use of headphones by our listeners with all those millions of portable music players out there.)

Once we decide to work this way we can reap some real advantages from it. For example, if I have really good headphones I have less need for big, expensive loudspeakers. The things I need speakers for—checking the stereo image, the direct to reflected sound balance, etc.—can be reproduced just fine by smaller, less expensive loudspeakers (provided their basic sound quality is adequate). Other things—fine balances between instruments in the mix, little details of performance, tonal colorations, etc.—are better checked on top quality headphones.

Jerry Bruck has taken this idea to its logical conclusion for some of his location monitoring. On some of his smaller scale jobs, where he doesn’t want to lug around a whole van-full of equipment, he brings along the Cambridge SoundWorks Model Twelve speaker system.

You’ve probably seen the ads for it: “stereo in a suitcase.” Two small satellite speakers and a small 3-channel amp fit into a medium sized carrying case that also has a built-in woofer. Unpack the amp and the satellites and the case becomes the subwoofer of a powered 3-piece system. According to Jerry, the sound quality of the Model Twelve is quite good—certainly accurate enough to tell him what he needs to know. Then for the fine details, on go the headphones.

[Editor’s note: at the time of this writing, the Cambridge Soundworks system was, if not unique, unusual and worthy of mention in the industry. Nowadays there are a lot of fairly portable 2.1 speaker systems with tiny satellites and a reasonably portable subwoofer that might serve as alternatives to headphones, or even stereo coaxial systems with optional or no subwoofer that can do the job. Recently reviewed speakers of this type include the Equator Audio D5, reviewed December 2011, and the Pelonis M42, reviewed April 2012.]

I’ll leave you with this thought before we consider how to evaluate different headphones:

“It is an axiom of any recording technique that the final result is only as good as the monitoring system used when making the recording. The more accurately the recording engineer can hear throughout the process, the better the final result will be.” —Streicher and Everest

See you next month as we go into the home stretch with testing criteria and suggested listening material!

Part 1

Part 2

Recording Magazine sends out a newsletter to its subscribers every few weeks. The newsletter is (coincidentally) titled “Sound Advice” and this month it features a new series on headphones and monitors. I asked permission to reprint this newsletter (and will ask to reprint the others in the series as well) so that those of you with home studios can also benefit from the information. I want to personally thank Brent Heintz, VP/Associate Publisher for granting permission, allowing me to share this great information with you.

Please visit Recording Magazine‘s website and their Facebook Page.

Voiceover usually deals with a singular signal (your voice) and therefore it is typically mono. However, the importance of space and spatial recognition cannot be overstated. By their very nature, how you hear headphones and monitors greatly effects how you hear yourself and your ability to interpret what you hear.

So… please enjoy this installment from Recording Magazine’s Sound Advice on Acoustics.

Welcome back to Sound Advice on Acoustics! We’ve been discussing the question of whether headphones can serve as adequate replacements for studio monitors, and at the end of our last installment, author Robert Auld said the answer to that question is “Yes, but.” It’s time to find out what he means, starting with the “Yes” part…

***

There are many situations where headphones have the potential to offer a higher quality of sound than loudspeakers:

~ They are not dependent on room acoustics, which can vary tremendously. As a sound reference that is consistent from venue to venue, headphones are a uniquely practical solution.

~ Most practical high-quality loudspeakers use more than one driver for each channel and need a crossover network of some sort. The potential for sonic problems with this arrangement has always been a challenge for speaker designers. Headphones can bypass such problems entirely by using a single driver for each channel.

~ There is no agreement as to the ideal polar radiation pattern for a loudspeaker. A variety of approaches are found in both consumer and professional settings, and they all interact with the listening room in different ways. With headphones this is not even a consideration, let alone a problem.

~ The very characteristic that makes the most difference in the way headphones sound—the lack of interaural crosstalk—makes them revealing of details in a recording to a degree that no conventional loudspeaker setup can match. This is one reason why many classical music engineers use them: if you need to catch things like that smudged entrance in the second violins or a fluffed note by the bassoonist, headphones will tell you about it much quicker than loudspeakers will.

~This same precision in rendering detail makes headphones superior for editing stereo program material. They reveal what is really going on at the splice point much more readily than loudspeakers—most of the time. (I’ll let Jerry Bruck tell you about the exceptions in a future installment of this newsletter.)

There are many practical advantages to using headphones as well:

~ They are lightweight and portable.

~ Dynamic-element phones have no need for large, powerful, expensive amplifiers. Suitable headphone amps are already built into a lot of recording equipment, and separate headphone amps are usually small and cheap compared to speaker amplifiers.

~ Closed-back headphones provide some isolation from your surroundings, making it possible to monitor where it would otherwise be difficult or impossible.

~ Some headphones are capable of deep bass response normally found only in very large full-range loudspeakers or in subwoofers. If you record pipe organs for a living—or, which is a lot more likely in this day and age, you record dance music or other bass-heavy musical genres like hip hop—you may find this useful.

~ Did I mention that they are lightweight and portable?

Even the more expensive top quality headphones offer more “bang for the buck” than loudspeakers. For example, the Sennheiser HD 580 has a street price of about $250. This gets you dynamic element headphones that are considered to be near-equivalent to the most esoteric electrostatic models. Loudspeakers with equivalent sonic performance could easily cost five times as much, or more.

But if it was really that easy, all the time, for everyone, there wouldn’t be loudspeakers in professional studios any more, would there? Tune in next time, when I reveal a subtle, annoying, even fatal fly in the ointment that more than adequately explains why even the smallest budget studio must have speakers as well as headphones. See you then.

Part 1

Recording Magazine sends out a newsletter to its subscribers every few weeks. The newsletter is (coincidentally) titled “Sound Advice” and this month it features a new series on headphones and monitors. I asked permission to reprint this newsletter (and will ask to reprint the others in the series as well) so that those of you with home studios can also benefit from the information. I want to personally thank Brent Heintz, VP/Associate Publisher for granting permission, allowing me to share this great information with you.

Please visit Recording Magazine‘s website and their Facebook Page.

One quick note: I did not reprint the first installment from last month on SOUND4VO because I didn’t feel it had enough information from which the majority of the voiceover community could benefit. Voiceover usually deals with a singular signal (your voice) and therefore it is typically mono. Many of the concepts you will read about in this article are critical for music, because music is typically in stereo (or surround sound). However, the importance of space and spatial recognition cannot be overstated. By their very nature, how you hear headphones and monitors greatly effects how you hear yourself and your ability to interpret what you hear. This article begins to deal with those issues.

So… please enjoy this installment from Recording Magazine’s Sound Advice on Acoustics.

Welcome back to Sound Advice on Acoustics! Last month author Robert Auld presented us with some intriguing problems that seem to have a common solution, if a radical one: What would happen if we elected to do all of our tracking and mixing and mastering with headphones rather than speakers? The answer to that question is a complicated one, and we’re going to spend the next few months taking it apart. Read on!

***

First the bad news: headphones really sound different from loudspeakers. Let us count the ways.

“The principal problem with headphone listening is you have no mixture of left and right channels; they’re piped directly into the respective ears. Because of that it is very hard to judge the width of your stereo stage, the amount of center that you’re getting, as opposed to left and right. You tend to misjudge that on headphones.”

The fancy name for what Jerry is describing is interaural crosstalk. Loudspeakers have lots of it (if your right ear can’t hear the left loudspeaker, something is wrong), but headphones have none. Mr. Bruck continues:

“A sometimes very serious misjudgement on headphones is to think that it’s wetter than it really is. You find on loudspeakers that you are much closer in perspective than you thought you would be listening on phones.”

The reasons for this are a bit complex, but they probably have a lot to do with aural masking—that is, with the tendency of one sound to mask another. In this case we are dealing with direct sound (a lead vocal, for instance) and reflected sound (as in the reverberation stimulated by that vocal). To quote another authority:

“Angular separation between direct and reflected sounds has a minor effect on the audibility of the reflections, except when the two are coincident, when the reflection tends to be masked by the direct signal.” —Ron Streicher and F. Alton Everest, The New Stereo SoundBook, 2nd edition.

In other words, if the reverb is coming from the same direction as the vocal or very close to it, it will tend to be masked by the direct sound. Here is how I think this applies to the headphones vs. speakers question.

With typical stereo loudspeaker monitoring the angle between speakers is about 60 degrees, or 30 degrees to each side of our listening position. This is a small portion of the 360 degrees over which we hear. It is safe to say most of the sound approaches from in front of us.

With headphones the earcups encompass an angle of 180 degrees relative to our ears, equivalent to speakers placed 90 degrees to each side. This is a big change, and it allows for greater angular separation between at least some of the direct and reflected sounds in a recording. A portion of the reverberation will literally be unmasked, and so the recording will sound subjectively wetter.

Experimental data on angular separation and masking imply that this difference is equivalent to increasing the reflected sound level by 5–10 dB. This would certainly be an audible difference, and it bears out Jerry Bruck’s observation (and my own experience). But there is one circumstance where “it sounds wetter on headphones” does not apply. This is when you are making a binaural or quasi-binaural recording.

In its purest form, binaural recording uses small-diaphragm microphones placed in the ears of an anatomically correct dummy or, less conveniently, in the ears of a real person. Then there are quasi- binaural microphone arrays like the Crown SASS that mimic the ear spacing and acoustic shadowing effects of the human head.

In either case, recordings made with these systems and reproduced with headphones preserve the spatial cues of the recording environment with considerable accuracy. This allows our brain to sort out the direct and reflected sound as it does in real life, with a gain in realism and clarity that can be really startling.

When you play the same binaural recording over loudspeakers the spatial cues are altered. What had been all around you is now placed in front of you, as if viewed through an open window, and—masking effects or not—it tends to sound more distant.

This is, of course, a special case, as most recordings use conventional microphone arrays that do not preserve spatial cues accurately, regardless of the playback method. So lacking a realistic acoustic model to work with, our brain resorts to other methods of analysis, and things like masking effects assume greater importance.

So far we’ve learned that headphones create a weird stereo image and do strange things to reverberation. What else have we got to look forward to from our potential critical monitors? Let’s have Jerry Bruck talk about low frequencies:

“Low frequencies are only partially a question of what you are hearing with your ears. A lot of it is, in fact, called “skin effect,” borrowing a term from another discipline. No matter what the frequency response of the headphones turns out to be, no headphone ever gives you the sense of low frequencies that you get from speakers.” This is why Hollywood doesn’t use headphones when it wants to make you feel an earthquake or an explosion.

If headphones differ from loudspeakers in such significant ways, can we still use them as critical monitors? The answer, I think, is “Yes, but…” Starting next time, we’ll look at the advantages that might make us say “Yes”, and then follow up with the “buts”. See you then!

Recording Magazine sends out a newsletter to its subscribers every few weeks. The newsletter is (coincidentally) titled “Sound Advice” and this month it features the ninth in a series about room acoustics. Room acoustics is one of the biggest concerns for Recording Magazine readers. I know that this is also a big issue for those of you in the voiceover world. I asked permission to reprint this newsletter (and will ask to reprint the others in the series as well) so that those of you with home studios can also benefit from the information. I want to personally thank Brent Heintz, VP/Associate Publisher for granting permission, allowing me to share this great information with you.

Please visit Recording Magazine‘s website and their Facebook Page.

Here is the ninth newsletter in the series on Room Acoustics:

Welcome to Sound Advice on Acoustics! We’ve started off this e-newsletter with a long multipart look at the basic concepts of acoustics and room treatment. In the coming months, we’ll have a variety of shorter articles on all manner of important acoustics ideas, reinforcing the basics and adding tips and tricks you can use in your room. But for now, let’s wrap up our primer with a few final notes, shall we?

This article has focused on control room acoustics, but the issues in the live (tracking) room are the same, though treatments will reflect the different usage of that space. Room modes introduce the same problems, and the same solutions apply. Additionally, being familiar with whatever standing waves may be present in the recording space can help the engineer in determining where to place instruments and microphones (to avoid a mic ending up in a null, for example).

Controlling reflections is also desirable in the live room, but here the criteria may be a bit different. In the recording room we might be more forgiving of colorations and echoes than in the control room. Rather than being a reference environment, the live studio space needs to support the sounds of singers and instruments, and here the acoustics may benefit from some “pleasant coloration” and enhancement of sound, though we certainly want to maintain control.

We may want to have different areas, some more ambient, some more dry (damped), to suit different recording situations, but this need not be implemented as rigorously as in the control room. One common approach to providing varying acoustics in the recording space is to mount two- or three-sided panels with different degrees of absorptive and reflective materials on the different faces. These panels can then be rotated individually to create the desired degree of ambience for a particular session.

In our discussion of control room acoustics we focused on early reflections and ambience, and didn’t really look at reverberation in detail, other than to point out the desirability of a diffuse sound field. In control rooms there’s very little reverb tail by design, so as not to overshadow the ambience and reverberation in recordings. In the live space, however, a good reverberant sound field is an asset, imparting a natural richness and dimension to recordings made there.

Had we focused on live room design, we’d have spent a lot more time discussing how to measure and control various aspects of the reverberant sound field via design criteria and room treatments. Fortunately, there’s no shortage of reference material available on this topic (see the recommended readings, and we’ll almost certainly get to this topic in a future installment of this e-newsletter!).

And there we are, several months after we started, with hopefully a good grasp of the basics. This article has tried to provide an introduction to the complexities of room acoustics, with a few practical suggestions for remedies and treatments. Anyone who plans to really get involved in designing and tuning the acoustics of a recording studio will want to delve much more deeply into the relevant physics and math. An excellent textbook on the subject is the Master Handbook Of Acoustics by F. Alton Everest, which contains both theoretical and practical information in great detail. Two other books that present practical design templates for DIY studio construction are Sound Studio Construction On A Budget, also by Everest, and How To Build A Small Budget Recording Studio From Scratch, by Mike Shea and F. Alton Everest (he does get around, doesn’t he!).

There’s also plenty of information to be found on the Internet that could be of help to any would-be studio designers out there (try the websites of some of the companies that make studio acoustic products, for starters). And to anyone who is designing and building their own recording space, large or small, good luck—it can be daunting, but the results will be worth it!

There’s lots more to learn and lots more to share… come back next month as we bring you more Sound Advice on Acoustics!

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