Recently CRAS hosted Shure’s wireless mic seminar in our huge 6,000 square foot live sound room. Shure microphones are a mainstay of the audio industry, and it’s no surprised we have quite a large collection of Shure mics, from SM57s and 58s to KSM32s and SM7Bs.
Pictured: Instructor Pete Bish, Adolfo Acevedo, Administrator Kirt Hamm, Instructor Keith Morris
As a thank you gift, Shure representative Adolfo Acevedo presented us with some incredible new gear! We now have our hands on the KSM313 dual-voice microphone, as well as the SRH 840 and 940 headphones.
The KSM313 is a dual-voice ribbon microphone. One side of the KSM313 provides a brighter character that shines on your vocals, while the other side offers a rich, full sound that’s ideal for your amplified instruments. The ribbon in this mic is made out of Roswellite material, which is capable of withstanding up to 146dB SPL! The list price on this mic is $1295, and while it appears to be out of stock at SweetWater.com, you should be able to find one soon.
The SRH840 and SRH940 are high quality, professional grade headphones that are incredibly comfortable and provide great performance. Thanks Shure!
Deathcore metal band Emmure got a dose of danger at their Moscow show Tuesday night. During their set, singer Frankie Palmeri got a strong electric shock which was delivered through the microphone, that took him straight to the ground. He is OK now, but the ended up having to cancel the rest of that show. You can check out the video of this here -
So what went wrong? There isn’t any official word on what caused the shock, but we can consider a few things. First off, in America, the active voltage on most electrical outlets is 120V. In Russia, where this show happened, the devices run off 220V circuits, so that is a bit more of a substantial shock. Most music equipment runs on electricity, even dynamic mics, such as the SM58 seen in the video, will use a small amount of electricity to transfer the audio information from the mic capsule to the preamp.
Looking at a standard XLR cable, used for most microphones, you will notice three pins. This is similar to the electrical plug in the wall, where there is a hot, neutral and ground connection. Most of the electricity resides on the hot and neutral connections, and the ground is a safety design to balance any excess power and prevent shocks from happening.
In some cases, you may experience a “ground loop”. This occurs when there are too many grounds, or the grounds are incorrectly connected, and can result in a steady hum. In the US, that would be a 60Hz hum, since we us AC voltage that runs at that frequency. Russia runs at 50Hz, and also uses AC. This hum can become a bit of a problem, especially in a large PA setting, adding unwanted noise and load to the sound system. Most electronic and electrical devices have the possibility of a ground lift, which will disconnect the ground in order to prevent a ground loop from occurring.
There is a good chance that improper usage of a ground lift is what caused this to happen. There may have also been incorrect wiring in either the mic, the mic cable, or the preamp/distro box it was connected to. In some cases, I have seen people buy 3-prong to 2-prong adapters to work as a ground lift, or simply just pull out the ground pin from the connector itself. This is incredibly dangerous, and as we can see in the video above, accidents can certainly happen.
There is also speculation that perhaps there was phantom power applied to the mic. Phantom power is a 48V DC feed that is used to power most condenser microphones. While it is possible this was the culprit, it is highly unlikely. Even if that is the case, there must be some bad wiring in either the mic and/or the mic cable to cause this. While most dynamic mics don’t require phantom power, they do have built in transformers to prevent damage from occurring if phantom power is accidentally applied.
With all this in mind, this is why we have dedicated classes here at the Conservatory just for electronics and electrical troubleshooting. Today is in fact Troubleshooting day, with teachers Jim Bender and Terry Bussoletti going over information like AC versus DC, impedance, voltages and how circuits work, so that you as an audio engineer can run the safest shows possible!
To start off with, audio is our perception of differences in air pressure. Common vibrations, or frequencies, are what our ears use to determine what a sound is, how high the pitch is, and where it is coming from. When recording audio to an analog style medium, sound waves are converted or “transduced” in the microphone capsule. The diaphragm of the mic is pushed, and that changes the active voltage going down the microphone cable. The electronic signal can then be processed as negative or positive movement, instead of physical pressure. Speakers work much in the same way that a microphone does, just in reverse. They take the electronic signal and use that to push the speaker diaphragm in and out, thus creating sound pressure waves that we can hear.
When we are going to record to a digital medium, the electronic signals need to be converted into digital, or binary, code. This is the job of the A to D converter – Analog to Digital. Sometimes these are referred to as ADCs, and then on the back end there are the DACs, or Digital to Analog Converters. In many cases, we call these devices “interfaces”. They are designed to accept an incoming analog signal, and they can then convert it into digital audio that can be worked with in a DAW, or digital audio workstation. Often these interfaces can connect using USB, Firewire, or their own proprietary interface card that must be installed into the computer.
Digital audio is based on taking samples, or “snapshots”, of the waveform. Instead of having a continuous flow of information, like analog audio does, digital audio is just a series of pictures of the audio. Similar to how movies are a series of pictures that are played one after another, digital audio is a series of samples played one after another to give us the impression of true audio.
There are two components to digital audio – sample rate and bit depth. Sample rate refers to how many snapshots are taking of a waveform every second. This directly relates to frequency. The higher the sample rate, the more accurate of a representation the digital audio can present, and the higher the frequency can be recorded. For example, CDs have a sample rate of 44.1kHz, or 44,100 snapshots per second. Using what is know as the Nyquist theorem, the highest possible frequency that can be recorded is 22,050Hz, which is just above the standard range of human hearing.
Bit depth correlates to volume, or amplitude. One bit represents two possible values – either 0 or 1, on or off. If we were recording using one bit quality, we would only hear sound very loud, or completely silent. If we increase the bit depth, we can thus get better resolution in the sound. With two bit quality, there are four possible values – off, quiet, louder, loudest. This way we can start hearing the “dynamics” of audio. CDs use 16 bit depth recording, which allows for over 65,000 levels of volume.
The Conservatory strives to be at the forefront of modern technology. While we hold on to the building blocks of all that has led to what we know now as audio engineering, that doesn’t mean we stay in the past. We have classic gear, from PCM-80s to Studer A-827s, Universal Audio 1176s to Pro Tools HD2s, CRAS encompasses all that exists in the audio realm.
While we teach all that is analog, from Otari to SSL, we also cover modern gear, from Komplete 6 USB interfaces to VENUE D-Show systems, we cover everything you’ll need to know to be a comprehensive audio engineer, ready to take on the most daunting tasks, from doing sound design for Bates Motel, or sound quality assurance for the newest video games like Bethesda’s Dishonored .
We always have visits from big names in the industry – the past year we’ve seen visits from PRG and Shure, had involvement with local music festivals, and even had audio industry leaders visit our school – from studio managers to PR people, we have it all.
Here is a video from when Studer visited our campus in 2012 and showed us some of their hottest gear. You can believe this was a unique visit and something that should not have been missed!
Last Thursday, the Conservatory of Recording Arts and Sciences was lucky enough to be one of the stops on the John Lennon Educational Tour Bus US tour! Aside from CRAS, they visited NAMM, the Sundance Film Festival, SXSW, the Summer X games, as well as countless other locations.
The John Lennon Educational Tour Bus is a non-profit, state-of-the-art mobile audio and HD video recording and production facility. In its sixteenth year, with the very newest technology and gear, the Bus continues to be dedicated to providing young people with tours of the studios and participation in free songwriting and multimedia production workshops. With the assistance of three on-board engineers, students learn how to write, perform, record, and produce original songs, produce and shoot music videos and documentaries and complete a broadcast quality music video – all in one day!
We got an exclusive tour of the bus and all of it’s incredible workings! I was amazed that they could really fit all that technology into one bus. From pre-production to post-production, live instruments to video creation, this bus can do it all. Three individual rooms, each separated by audio and visual isolating doors, contribute to the ongoing promotion of audio education in the world. Recently they’ve been touring the United States, but once they are done with this tour, they are headed over to Europe to bring the same amazing show to a new stage.
We will certainly have more about this, but for now, check out our quick video slideshow:
Today CRAS will be hosting a special guest – the John Lennon Educational Tour Bus! The bus is a three studio engineering dream on wheels, funded by a non-profit organization designed to encourage the youth of America to follow their musical and video dreams. The bus is a full fledged production suite – containing three separable studios focusing on video, music and production arts. Full of gear from Avid, Apple, Apogee, Audio-Technica, Neutrik, Genelec and SSL!
If you can’t make it down to our Gilbert campus between 10:30am and 5:30pm today, you can certainly check out this video walkthrough of the bus:
The Tour Bus is funded by donations, and you can donate directly to them through their YouTube channel here.
Mixing is an integral part in making a good sounding recording. There are three main steps in the recording process: recording, mixing, and mastering. Each of these steps change the sound of the audio incredibly, and each is important in its own way.
Today is Compression Day here at CRAS. Compression is typically used during the mixing part of the recording process. There are many different techniques that can be used to make a recording sound great, and one of those techniques is compression. Initially, a mix engineer would use the faders to control level dynamics of the tracks in a session. They would make sure the vocals are loud enough to be heard over the instruments, or ensure the vocals weren’t drowning everything else out. They could also bump up the levels of the guitar during the solo, and then bring them back down into the mix during the rest of the song to have a good balance between instruments.
Someone came up with the idea to make a device that was capable of interpreting the audio, and would be able to automatically compensate for level differences. This device is known as a compressor. There are physical units that typically reside in an outboard gear rack that can be patched into the signal chain. There are also software plug-in compressors that can achieve the same task while working within a digital audio workstation, or DAW. A third option is analog tape compression.
Each of these types of compression have their own characteristics, and some effect some instruments or vocals better than others. That’s why here at the Conservatory of Recording Arts and Sciences, we teach students about all of these aspects. We go over tape machine calibration to get great tape compression and saturation, the basics of signal flow and inserting outboard compressors, as well as “in-the-box” mix techniques in DAWs.
Here is a great video that goes over some basic ideas of compression, and gives great examples of how they can be used creatively in audio and music production.
Today at CRAS 1st cycle students are going over MIDI operations using Logic Pro, one of the most comprehensive audio production softwares available. Logic is included in the laptop package at the Conservatory, which includes a brand new MacBook Pro, Logic Pro, Pro Tools, iWork and so much more.
MIDI, while being 30 years old, is a very versatile protocol. Not only can it deliver note values, but it can also communicate volume, panning, sustain, and over a hundred other parameters. Velocity is one of these parameters, and a lot of people confused volume and velocity as being the same things.
Volume is how loud the note is going to be played. Velocity is how hard the note is going to be hit. While hitting a note softer can result in a quieter sound, it is achieved in a different way. On synths that support it, velocity can make a huge difference in the feel of the music, whether it is a hard hammering piano note, a fluttering snare flam, or a throbbing bass hit.
The Studer/Soundcraft demo truck parked at the CRAS today to give students and staff a chance to see the latest consoles in recording, broadcast and live sound production. Products on display include the Studer OnAir 1500, Soundcraft Si Compact 24, Soundcraft Vi1, Studer Vista 1, Studer Vista 5 M2, and Studer Vista 9.
The CRAS teaches all things necessary to be a great engineer including the ability to speak the language of music. While you don’t have to be a virtuoso to record audio, it definitely helps to be able to converse with the artist on both creative and musical levels. CRAS instructor and author Brian Burrill regularly holds Music Theory Clinics for any student interested in upping their skills. The CRAS’ also sponsors other extracurricular clinics including mic, preamp and processor builds as well as workshops and field trips for AES student chapter members.
