Tag: Clipping

SMD Products Now At Sonic!

They say you should be careful what you wish for but in this case you can stay care-free. You can now sleep soundly because Sonic Electronix now carries an assortment of products  from the legendary Steve Meade. If SMD products were potential life-long companions, then you would want to make sure to treat them to a nice lobster dinner and make sure to call them back after the first date.  What i’m getting at here is that they are very good quality products and have been proven to be one of the best among professional and amateur installers alike. We are very excited to be getting these in and I might even pick up one up myself!

SMD DD-1

SMD DD-1

SMD DD-1

The workhorse of the SMD line is the popular SMD DD-1.  This unit is a distortion detector and analyzer which is used to set gain and eliminate distortion by matching the source units output level.  This is a must have tool for any sound system due to the fact that any system can experience clipping.  It includes easy-to-read LED indicators that will tell you if your system is experiencing a distorted signal and will tell which way to adjust your gain to eliminate clipping.  The DD-1 is powered by a 9V battery in order to isolate it from the vehicles electrical system.  This guarantees that you will only be measuring the audio signal and not the noise in the vehicle’s charging system.   In addition to all these great features, a test tone CD is included for accurate calibration.  There is also a high voltage version called the SMD DD-1 HV.

SMD CC-1

SMD CC-1

SMD CC-1

Another essential tool is the Crossover Calibrator called the SMD CC-1.  This calibrator tool will allow you to seamlessly set electronic crossovers on your amplifiers to their desired frequencies.  It features a “competition mode” which can be used to match frequencies and gains of any 4 channel amplifier or multiple monoblock amplifiers.  When it comes to applications such as these, it is very important to make sure the amplifiers are putting out the exact same amount of power especially when you have two or more amplifiers on a dual voice coil driver.  The unit also includes an RCA harness so you can measure the output voltage of your headunit directly.

You can take it one step further by adding an LED sound system output display called the VU-DIN.  This display will give you a real time indicator of your music and will specify how close you are to clipping your signal.  Comment below and tell us what you think of SMD!

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How to Properly Set Gain on Your Amplifier

Why Set Gain?

NVX JAD8004

NVX JAD8004

People end the lives of their subwoofers everyday and one of the most reoccurring reasons is due to improper gain settings on their amplifiers.  A majority of people mistake gain to be nothing more than a volume knob but that misconception can lead to horrific subwoofer murders.  Knowing exactly what gain is and how to set it will not only prevent your precious power-pushing woofers from meeting their maker, but will also give you the cleanest output possible.  Gain is basically defined as input sensitivity and is used for matching the output from different sources so that they reach optimal performance and minimal damage.  The main thing you are trying to avoid is clipping your signal. Clipping is the distortion that occurs when an amplifier is pushed beyond it’s limits.  At high volumes the music will sound muddy and will cause unpleasant sounds.  If you avoid clipping your signal,  then you will give both your amplifier and woofer a longer lease on life.

Procedure  

With all of that being said, here is a quick way to set your gain:

  • Insert a CD into your headunit that you know to be fairly loud.
  • Play a song and set the volume on your headunit to about 75%.
  • Set the gain all the way down and slowly raise until you experience clipping (audible distortion).
  • Once you reach the clipping point, set it back down so you no longer experience a clipped signal
  • The volume that your headunit was set at during this procedure is now your head unit’s MAX volume.  This is the loudest it will play without clipping and will sound good and clean if you have done it right.
JBL GTO-751EZ

JBL GTO-751EZ

Please note that this is not the most accurate way of doing this but it will get you very close.  If you’re looking to get the most absolutely accurate result then you’re going to want to use an Oscilloscope or Digital mutimeter.  Just make sure you know how to use them!  Another alternative is getting an amplifier such as the JBL GTO-751EZ which features gain LED indicators that will tell you if you signal is being clipped.  For a more in-depth analysis please read our knowledge base article here.

Have you guys ever experienced issues with your gain settings? Comment below and tell us about them!

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Proper Gain Staging in a Digital World


American Audio DB Display

Lets Cram Some More 1’s in Those 0’s

Gain is the measure of the ability for a circuit to increase the amplitude of an audio signal.  Gain staging is the process of optimizing the level of your sound signal to be recorded, broadcasted, or amplified into a PA system.   This is important to get the full dynamic range of your audio signal while avoiding the noise floor.

Warm and Fuzzy: Analog Distortion

In the world of analog recording audio is stored onto magnetic tape by arranging magnetically charged ferris particles onto a strip of mylar.   Analog recordings were a bit more forgiving of over modulated levels as the end result was a harmonically saturated distortion that is interpreted psychoacousticly as warmth.  VU Meter For this reason recording to two inch analog tape remains a coveted boutique media option in commercial recording facilities.   Analog equipment supports an extended headroom meaning that you have the ability to drive a channel “Hotter” before clipping  than the digital equivalent.

Cold and Sad: Digital Distortion

When you record audio digitally the analog signal is first converted from an electrical signal to a series of numbers that represent the amplitude of the analog wave form in a moment of time.  Clipped Audio This is done by using a binary system of code consisting of two digits “1” and “0”  Digital, get it?   In conventional digital audio these numbers are arranged in “words” consisting of 16 or 24 digits which look like this: “1101011000111010” These strings of digits represent a sample of amplitude for an instance of time.  All digital audio is comprised of these samples and the sample rate of digital audio refers to how many times per second the audio signal is sampled during the conversion process.  The most common sample rates are 44.1kHz, 96kHz, and 192kHz.   CD’s are encoded with a bitdepth of 16  i.e. “1101011000111010” at a sample rate of 44.1kHz.   This means that a 16 digit sample is taken 44,100 times per second.

Clipped Waveform The absolute max level that can be achieved with digital audio is 0dB.  Any signal that surpasses 0dB is a clip as there will be no digital number to represent the level.  All other levels are displayed as –XdB So what does all that astronaut speak mean for you?  DON’T HIT ZERO!  No matter what your bit-depth or sample rate the highest achievable level is 0dB as your DAW and all digital audio playback devices are not able reproduce anything louder, therefore instead of the comparable warm distortion in an analog device, clipping digital audio results in nothing other than playback failure awful sound.

To avoid this problem is it important to keep an eye on your level meters.  Most level meters have a clip indicator where the top red LED of the meter remains lit until it is reset.   When this happens it often means you may have to have another go at your take, pass, or mixdown.

Floor to Ceiling

Another concern with gain staging is a level that is too low.   After making the necessary boosts or compression to a channel of audio that is recorded too low, the noise generated from the microphone preamp, summing amp, and other circuitry in your signal chain is amplified as well, resulting in a much noisier version of your intended recording.   So it is very important that you have levels that are hot enough to remain clean while avoiding clipping.

Clipped Audio levelsIt is good to shoot for a max level that is well under your ceiling of 0db while remaining hot.  A good benchmark for the sharp transients of a snare for instance is to peak at -6dB while the majority of your tracks should hover around -12dB peaking occasionally at -6dB.    The use of a good “brick wall” limiter is a good way to wrangle in those stray transient signals that can otherwise clip your track.

During the mixdown phase it is important to maintain an adequate amount of headroom so that your final mix can be mastered.    About -4dB is a nice target to shoot for a pre-mastered mix.   This will result in ample headroom to really squeeze everything out of your mix.

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