The Art & Science of Audio & Video

Balanced Input or Stereo Input? Mic Input or Line Input?

I want to discuss a topic that I get asked about constantly. It’s the confusion surrounding balanced inputs verses stereo inputs and the true differences between mic and line inputs. First and most obvious are the balanced and stereo. This is something that has become a more prevalent problem in recent years because of the popularity of portable MP3 players and the use of laptops running special software for athletic programs and multimedia presentations. So here’s where the problem usually starts, someone takes the convenient 1/8″ stereo mini and assumes that the fact that it has a Tip, Ring and Sleeve translates into a balanced input of pin 1(G), 2(+) and 3(-). Well as you’ve probably figured by now this is not the case. Continue reading


June 22, 2008 Posted by | Class: E=MC2(+/-3db), FAQ's | , , , , , , , , , , | Leave a comment

Power amps with & without controls…..what gives!

How do power amps work that have no volume controls on them?

Actually no amplifiers have “volume” controls. The power amp it self is fixed at a given output, let’s say 100W for example. If the amp does have a “volume knob” it is actually a control associated with the pre-amp stage of the unit. When turning that knob you are actually adjusting the input sensitivity. So in a scenario where you have a separate pre-amp and amplifier the pre-amp will take the signal from the source component and allow you to manipulate the signal with the use of maybe tone controls, attenuation, etc. The signal then is passed along to the amplifier, which is once again fixed at a given output. So controlling the amount of attenuation on the pre-amp will have a direct effect on the amplitude of the signal at the input of the amplifier. So the amp will amplify whatever signal is at it’s input by the same amount regardless of amplitude.

So simply put the amplifier is only capable of 100W of amplification. How “loud” it plays (or the resulting amplitude at the output) depends on the level of the signal you present to it at the input stage. Fort the units that do have attenuation controls you have the luxury of controlling it sensitivity to the input signal.

by Jason Levert

March 29, 2008 Posted by | Class: E=MC2(+/-3db), FAQ's | , , , , , , , | 1 Comment

How to properly set delay speakers

When configuring a sound system how do you properly set the delays?

The ultimate goal when setting up delay speakers is for the listener to not even notice the delay speakers are there. Yes, as silly as it sounds it’s true. A properly configured delay will give the illusion that the sound is still coming from the source and not the delay itself. There are several ways to go about a proper setup for your delays. Believe it or not you can actually configure a delay very precisely with a tape measure and not expensive test equipment. Just remember one very simple rule, sound travels 1130 feet per second (at sea level with 70% relative humidity at 72 degrees). In other words sound will travel 1.13 feet every millisecond. So if your delay speaker is 35 feet away from you primary speakers a delay of 31 milliseconds would be right on the money. Of course there are several sophisticated and expensive electronics to do the same thing. They use a calibrated microphone to compare the arrival times of a reference signal from the main speakers and the delay speakers as it arrives at the microphone. This difference in arrival times is obviously your delay time.

However there is also a phenomenon known as the HAAS effect which is too in depth to discuss in one post but what’s important to know is how it relates to settings delay times. In the study of psychoacoustics it is found that often times delaying the “delays” even further behind the arrival time of the primary speakers actually enforces the perception that the sound is originating solely from the primary speakers. This is because the secondary arrival is suppressed due to “involuntary sensory inhibition” which correlates to the human ear’s ability to localize sounds.

by Jason Levert

March 29, 2008 Posted by | Class: E=MC2(+/-3db), FAQ's | , , , , , | Leave a comment

My system doesn’t sound like it did in the store. Should I buy an EQ?

My system doesn’t sound like it did in the store. Should I buy an EQ?

NO! EQ’s are probably the worst addition to any system you could make. The acoustical characteristics of your room affect the sound of your system as much as any other component in the chain. EQ’s can be used successfully when you have the proper equipment to calibrate them. Most EQ’s available on the consumer market are poorly designed and are more detrimental to you sound quality than they are helpful. Now the units manufactured for pro audio use are far superior and can help you achieve the results you need without inducing unwanted phasing and harmonics. Most if not all pro audio installations required the use of one or more EQ’s because every installation is so drastically different. The majority of the time in a residential situation you will have more success tuning the room itself. Simply pay attention to system placement, furnishings, flooring, window coverings, etc.

by Jason Levert

March 29, 2008 Posted by | FAQ's | , , , , | Leave a comment

The Critics Have Spoken but It’s You We’re Listening To.

At Gain11 I do my best to avoid subjective disagreements with any patrons on or offline. However recently I was heavily criticized for not going more in depth into more of my articles and/or answers. I kindly remind those critics that it is not our objective to be a replacement for qualified teachers and the many well-known training facilities spread about the country and of course those across the pond . I my self will spend my time in the shadows of these highly regarded teachers learning for years to come. We aim to be a resource that prepares those who want to take that next level and invest money in these classes and take full advantage of all of the professional and world-renowned facilities available to us all. There are plenty of books available that are too advanced for the beginner and those just interested in learning more about the field. If we can bridge that gap and get those just starting to a point where they can read these books without being overwhelmed in just the first chapter then we have accomplished our mission.

Of course with all this said we always encourage any feedback our readers may have critical or otherwise. If there are specific topics and or areas of study you would like to see us address just drop us a line and we will be sure to meet all of your requests as quickly as possible.

by Jason Levert

March 25, 2008 Posted by | A/V News, Class: E=MC2(+/-3db), FAQ's | Leave a comment

Lifting the Shroud on Graphic EQ’s

Q: I have been told many times that graphic EQ’s are detrimental to the sound quality of your system and can actually be counter productive. If this is true why do they remain so popular?

A: This often a misunderstood topic. Before starting let’s lay a little groundwork to build from. Graphic equalizers have a fixed number of filters set at pre-determined center frequencies. Now earlier graphic EQ’s and some current lower quality units were and are variable “Q”. This is where the problems originate. A Continue reading

March 23, 2008 Posted by | FAQ's | , , , , , , , , , | Leave a comment

Phase vs. Polarity

What is the difference between phase and polarity?

Simply put phase represents the relationship in time between any two or more frequencies. This range could be anywhere from 1 degree out of phase to 179 degrees out of phase. Polarity on the other hand is either correct polarity or reverse polarity. You can be “in” or 180 degrees out, period.

February 27, 2008 Posted by | FAQ's | , , | Leave a comment

Gold Plated Connectors – Fact or Fiction?

Why do manufacturers always boast about gold plated connectors?

Gold offers superior resistance to corrosion. Contrary to popular belief silver is actually a superior conductor to gold but it does not offer the same level of corrosion protection. Gold is however no slouch when it comes to conductive metals. It is second only to silver.

February 27, 2008 Posted by | FAQ's | , , , , | Leave a comment

Why Do Speaker Prices Vary So Much?

Why is there such a huge price range in speakers?

Explaining the gross price differences in speakers in similar to that of today’s automobiles. Some of the price variation is due to the difference is raw materials. The quality of wood, drivers, wiring, crossover components and front baffle materials. Sometimes it’s relative to the craftsmanship invested in the cabinetry itself. A poorly designed or poorly assembled cabinet will resonate coloring the music among other things like causing poor bass response. This is why you see some speakers with exotic front baffles made of marble, concrete or multiple layers of hardwood. A lot of it has to do with the amount of Continue reading

February 27, 2008 Posted by | FAQ's | , , , | Leave a comment

The Mysterious Crossover

What does a crossover do and how does it do it?

Crossovers determine which frequencies go to which drivers. This is what sends the “highs” to the tweeter and the “lows” to the woofer. A crossover can determine and affect several other factors as well. Such as the phase relationship between drivers and the spatial alignment better known as “time alignment” which is a copyrighted term. A crossover can be as simple as one filter or several filters acting together as one component. You will hear terms such as low pass filter, high pass filter and band pass filter. The crossover network is made up of various components such as capacitors, coils and resistors. Capacitors are used to filter out low frequency information in tweeters and midrange drivers. Coils, otherwise known as chokes, are used to eliminate high frequencies from woofers and some midrange drives.

February 27, 2008 Posted by | FAQ's | , , , , , , , , | Leave a comment