header image header image

Sound Advice

Creating A Better MP3 by Noah Mintz

February 19th, 2009

About two years ago, I set out to create a better-sounding MP3 file. I tried all the different encoders, bit-rates, and technical options. To my ears, there wasn’t much of a difference – they all sounded bad.

As a mastering engineer, it disappointed me to hear the musicians’ hard work end up like this. In the end, it didn’t matter why MP3 was technically inferior; all that mattered was that it didn’t sound as good as the 16-bit 44.1 kHz source, not to mention the 24-bit masters from which the CD was made. I concluded, then, that encoding a better MP3 was impossible. So now what?

MP3 was not going away. Even now it’s still the most-used and player-compatible lossy compressed format for audio, and I imagine that it will be for some years to come. So, if a better MP3 through improved compression and encoding is not possible, is there something else that can be done? The answer is yes. Create a better mix.

Creating a better mix creates a better MP3. Yes, of course this is obvious – but maybe not for the reasons you might think. Just like engineers in the ’60s, ’70s, and ’80s mixed with the limitations of lacquering (the vinyl record master), I believe mixing engineers should mix with some degree of awareness of the limitations of MP3 since it’s the way most people will listen to recordings. The good thing about this is that mixing with MP3 in mind will also create better mixes for CD or high-resolution production.
Here is a short list of tips with explanations:

  • Limit your limiting. Digital peak limiting during the recording or mixing process raises your noise floor, reduces your dynamic range, and adds to your overall distortion.
  • Use your available bandwidth. Mix to 0db. That means your peak should be at or near 0dB. For every bit of “headroom” you leave, you lose perceived bit resolution.
  • Record at the highest bit rate and sample rate possible. As Rupert Neve once pointed out, harmonics of higher frequencies exist in lower frequencies. Recording at higher sample and bit rates, even if the final source is 16-bit 44.1 kHz compressed MP3 files, will still sound better.
  • Avoid dithering. Despite what people say about dithering, it really only sounds good when added at the end conversion from 24 to 16. Dithering adds noise and noise doesn’t compress well.
  • Be aware of the MP3 compression process. Mid-range frequencies (vocals, guitars, snare drums) compress well. Everything else, especially broadband noise (bass, cymbals, air frequencies), are difficult to compress and can distort your MP3. Use this knowledge, especially in the mastering process, to shape some of your EQ decisions.
  • Monitor the side (difference) channel. Make sure it’s not distorting. Distortion in the side can really mess up the compression process. To monitor the side channel, invert the phase of either the left or right channel of the master bus and then put it in mono. The resulting audio will be what you want to make sure is not distorting.
  • Use a mastering studio that understands the MP3 process. There are limitations of MP3 that go beyond the audio quality. If you take one song and download it from different sources (legal and non-legal), you quickly realize that there is no standard to MP3 creation. They go from bad to worse. Beyond that, the metadata (the artist information that’s embedded into the file itself) is not consistent. Lacquer Channel (my mastering studio) launched enhancedMP3 in January 2009. It’s a CD-ROM portion on the audio disc (much like enhanced CD) that contains the highest-quality, artist-approved 320 KB MP3 files available. We use a custom proprietary process to ensure the file compresses the cleanest way possible. Read more about it at www.enhancedmp3.com.

MP3 is here for a while. Using some recording and mixing smarts, and using a mastering studio that understands the limitations of an MP3 file, will go a long way to ensuring that the sonic intent of the music is not lost.

Noah Mintz is a Mastering Engineer at Lacquer Channel Mastering and the creator of enhancedMP3.com technology.

In-Ear Monitors: Tips & Tricks: Part 1 by Keith Gordon

August 19th, 2008

In this issue, we’ll look at some tips and tricks I’ve picked up over the years for better working with in-ear monitors (IEMs), plus some interesting problems I have helped people overcome.
The major starting point for any IEM, or even MP3 player earphone, is fit. Without good fit, you are fighting a losing battle for quality sound right from the start. At the recent NAMM Show, I had a couple of musicians ask me why they could not get any more gain out of their lead vocalist’s IEM system. The minute they added the keyboards to her vocal mix, it compressed the vocal and caused the limit lights to activate on the transmitter and receiver belt pack.
As I continued to ask questions intending to dig down to the true root of the problem, it eventually was determined her IEMs fit so poorly that they fell out constantly. This indicated the “limiter” issue was really a case of her having a terrible seal at her ears. The poor seal meant she had a great deal of loud external stage noise to overcome, a good portion of the sound her IEM was managing to create escaping her ear canal, and very little low frequency content since a proper tight seal is necessary for good bass reproduction.
This aspect – the proper acoustic seal at the ear – is doubly important as there is a psycho-acoustic effect where our brains perceive an increase in bass/low frequencies as an increase in overall volume. In practical terms, this means getting a better seal for stronger bass or turning up the low end creates the effect of turning up the entire mix, but without the damaging effects to our hearing that would occur if we simply turned up the overall mix a seemingly equal amount. This allows for longer exposure times before the harmful effects of volume set in. This also means musicians should not wear their IEMs loosely with an intentionally broken seal so they can hear the outside world better. Instead, they should use audience or ambience microphones as a regular part of their monitor mix. These microphones can then be turned up by the monitor engineer between songs, so performers can keep wearing their properly sealed IEMs.
Next issue, we’ll continue with more on psycho-acoustics and other tricks of the trade.

Keith Gordon is a veteran audio engineer who began using IEMs in the mid-90s. Recently, he helped develop a DSP-based hardware/software IEM system in conjunction with Westone Laboratories. He can be reached at keithgordonca@gmail.com.

Live Webcasting From The Streets To The Corporate World: Part 2 by Brad Marshall

August 19th, 2008

Last issue, Brad discussed the basics of webcasting, as well as how to check your available bandwidth and get things started.

You have to figure out how many cameras you’re going to need, as well as the lighting and audio systems to support the webcast. If you are webcasting one person, for example, a two-camera shoot may suffice, with a simple audio system supporting one mic. Simple three-point lighting will also suffice: fill, direct, and back lighting. There are many sources to explain lighting for webcasting. Two sources I suggest are: Hands-On Guide to Webcasting by Steve Mack and Dan Rayburn, and The Streaming Media Bible by Steve Mack. If you are not using LED lighting, count on having at least two 15-amp circuits dedicated for it. If you are dealing with more than one subject, you may need to look at more lighting, more cameras, more complex audio, etc.
You have got your gear together – now how do you capture that audio and video? Well, if you are using a laptop or desktop PC there are many video capture cards on the market. If you are just dealing with a single voice, the sound card on most computers is more then adequate, but if you are doing something musical, you may want to look into an external audio card or USB device.
There are many USB, FireWire (IEEE 1394), and slot cards available to capture both audio and video. If you are doing a single camera shoot just go directly into your computer via FireWire. Do not go out and buy a USB “webcam” unless that’s the quality you are looking for … we are talking bad quality YouTube video here. Warning!!
Get devices that can be recognized by either Windows Media Encoder or Real Studio Basic or Flash encoding portals. Trust me, this can be problem! Some devices only show up with proprietary software that has to be loaded onto your computer. If you can afford it, make sure the laptop or PC you are using to broadcast is only doing the broadcast and nothing else. E-mail, surfing the web, downloading, or uploading data are not recommended during a broadcast. This may sound fundamental, but many people try to do these things while broadcasting, resulting in disaster.
For Mac users, Real Studio Basic and Flash Encoding Portals work fine – but not Windows Media Encoder. The simplest and quickest way to get up and running is to use a camera as your audio and video capture device and pass those signals through your camera, and into your PC using FireWire.

Brad Marshall is the Owner of Popular Minority Production, which brings live events to the Internet (www.popularminority.com). He is currently writing a 10-week course on Live Webcasting to the Internet for Conestoga College in Kitchener, ON. He can be reached at anytime at: brad@popularminority.com.

Live Webcasting From The Streets To The Corporate World: Part 1 by Brad Marshal

June 19th, 2008

So you have been asked to do a live webcast for your company, friend, community, or local band. You ask yourself: “What’s a live webcast?”
Don’t worry! I am here to help you out. I’ve done live webcasts on Queen St. Toronto, as well as the ivory towers of the corporate world. I started my career doing community events, which meant that I had no access to T1 or fibre connections with incredible amounts of bandwidth. Instead, I learned from the beginning how to do quality webcasts using standard household DSL and cable broadband. I started this work in 2002 when webcasting, or “live internet streaming” was in its infancy. Okay, let’s get you started.
If you’re in live production, you’re already 75 per cent of the way there and that’s good news, but before you can commit to doing a webcast for your over-excited parties, you must check the available bandwidth at your webcast location. Bring your laptop or make sure there is a computer on-site that is accessible to you.
Connect to the network and go to www.speedtest.net. This online speed test tool is fun and accurate. It’s like looking at the speedometer on your car – and it can be a real adrenaline rush. Click on the geographical area that is near to you. Don’t worry about the download – pay attention to the upload! Upload is important because you’re taking your broadcast out of your location to a multimedia server. Upload speeds can be from 100 kbps to 1000 kbps or higher depending on where you are. Do this test several times, using different locations, then average the numbers. If your upload speed is 200 kbps (average) then you should be webcasting at 100 kbps. Why? Bandwidth fluctuates, and if you are broadcasting at 200kbps and there is a fluctuation, your webcast will be kicked offline, so you need to leave some room.
You are not quite ready yet. If you are in someone’s home it’s fine to disconnect any computers on the network before your broadcast. If you are in a corporate environment, you may be behind five firewalls and a suspicious IT department. Go to the IT department and explain what you are going to be doing. Make sure you understand the culture of the network and how it’s used. Also, if you have to obtain a static IP (Internet Protocol) address, which you may need to do depending on the type of webcast you’re doing, only the IT department can do this and it may take time to sort out.
Warning! If you test your connection two weeks before your broadcast and everything is fine don’t assume when you return that it will still be set up for you. IT departments have huge responsibilities and things can change while you are gone. One more thing: Do not do a webcast using a wireless network … just don’t go there.

Brad Marshall is the Owner of Popular Minority Production, which brings live events to the Internet (www.popularminority.com). He is currently writing a 10-week course on Live Webcasting to the Internet for Conestoga College in Kitchener, ON. He can be reached anytime at: brad@popularminority.com.

Best Practices In Disk Keeping For Maximum Performance: Part 2

June 19th, 2008

Scott offered some introductory information on disk drives and the headaches of fragmentation. Here’s some advice on how to keep your disks running efficiently and effectively.

There are many tools available for dealing with fragmentation; some are even included with many typical operating systems used today such as Windows, which has an application built right in called Disk Defragmenter. Such tools can analyze the disks or RAID volumes to determine just how scattered the data is, where the blank blocks or sectors are, and then will proceed to reorganize the data so that it’s in sequential order beginning with the inner most blocks, moving the blank sectors to the outer ends of the disks where they belong.
Many of these defragmentation tools will allow users to schedule defrags so they are done when the system is not in use. In many cases, defrags should be performed on a daily basis, depending on how much data or content is removed and written in relationship to how full the disks are. The fuller the disks, the more frequently a system may need to be defragged. By defragmenting, your system could find renewed performance.
Another tool that can have a big impact on performance, especially write performance on a system, is virus software. Most of us have had, at one time or another, the misfortune of dealing with a virus and have been forced to be prepared for future scares. What we do not realize is that the very software we rely heavily on to combat these threats can severely impact our business productivity, especially in write performance-sensitive applications such as uncompressed video capture as well as professional audio software.
This happens because the virus software wants to scan each file as it enters the system as well as when the file is opened, and that process is time consuming. Even a millisecond can cause a drop frame or a write delay. Either can require a user to start over only to have it happen again. Not only can this be frustrating and costly, but also confusing. Not being aware of the issue could cause a software problem to look like a hardware problem. Of course, the solution can be as simple as disabling the software during the use of performance-sensitive applications.
As the industry continues to change, so too will the issues and demands facing disk management. In response, more and more solutions will become available for overcoming such issues. Having the knowledge and appropriate resources in place before encountering any obstacles can protect your day-to-day operations and essentially ensure streamlined content management and productivity.

Scott Leif is President and CTO of Globalstor Data Corp., a leading storage technology provider for the professional audio and video, post-production, government, medical, education, and military industries. He is responsible for designing high-performance storage servers and storage area networks widely recognized among film and video, post-production, and audio professionals.

70-V Audio Distribution: Part 1 by Al Whale

February 19th, 2008

When required to connect speakers over large areas with non-interacting area controls like halls or classrooms, the 70-V system is ideal, although it should be noted that some places consider 70-V systems to be unsafe, so the 25-V system is used instead.
Transformers are used at each speaker location to convert from the 70(25)-V system to the speaker impedance (eg. 8 ohms).

The 70(25)-V line from the amplifier is applied to the input of the transformer. The input selected is based on the maximum power needed from the speaker. Each speaker location comes from this same 70(25) volt line source (in parallel). The sum of the power setting of all transformers used should be less than the maximum power of the amplifier.
Be warned: if the total is over the maximum setting, the amplifier will be overloaded and there will no longer be a constant output. Switching a group of speakers in this situation will then affect the other speakers.

From the above calculations, the 10-watt tap will be 500 ohms, and the 5-watt tap will be 1,000 ohms. When wiring, a smaller gauge wire can be used to go long distances without affecting the audio due to line loss.
Example: If the total load on the 70-V line is 100 watts, from the above formula, the impedance would be 50 ohms. Using the practice of 5% max, the wire would have to be under 2.5 ohms. Checking wire tables, for 50-ft. run, the wire would only need to be #22 gauge (1.614 ohms). For 500 ft., the wire would be #12 gauge (1.588 ohms). This is far easier than using 8-ohm lines – #16 & #6 gauge, respectively.

Al Whale is Broadcast Technologist and Assistant Chief Engineer at CHBC-TV. He also performs maintenance, design, and installation se-tup. He has operated and taught sound in many church settings. Visit Al’s website at: www.whalco.ca.


4056 Dorchester Rd., #202,Niagara Falls, ON
Canada L2E 6M9 Phone: 905-374-8878
FAX: 888-665-1307 mail@nor.com
Web Site Produced by NWC