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

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

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

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

Convenience vs. Quality (finally getting the attention it deserves)

I have long be an advocate that MP3’s and all other heavily compressed audio formats have been the downfall of quality audio. I have been pleasantly surprised to see that some of the mainstream magazines both published and online have joined the crusade and are speaking out on their concerns as well. I recall back when we chose our CD players depending on whether or not it had Burr Brown DAC’s and

Obama or Clinton or McCain???

Last time I checked inanimate objects such as electronics and the field of science and mathematics don’t have a political affiliation!  So unless one of them has the power to alter the fundamental laws of physics forever  changing  the field of acoustics  I leave this topic to another blog!!!  Hopefully this allowed you a brief moment to rescind from the drama and smile if just for a second!

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

You say Micro I say Macro. I say Macro T.I. says Pico!

There hasn’t been nearly as much buzz surrounding the newly debuted Pico projectors from Texas Instruments as I would have expected. At CES they unveiled there latest mind-boggler with examples of projectors small enough to comfortably fit within a PDA or smartphone or MP3 player etc. With the widely excepted use of MS mobile office apps one can easily see how this could literally re-define the meaning of portable presentation. T.I. seems to be on fire at the present time with some of the coolest and most innovative ideas brought to market it several years. I would keep your eyes peeled for more to come!

by Jason Levert

Microsoft chooses Crestron for System Integration

In a recent ad campaign the statement in big letters across the page reads “Microsoft chose Crestron”. It goes on to explain that Microsoft made the decision to use the Crestron control platform as its exclusive partner to manage all AV and meeting room resources worldwide. Before you jump to conclusions this is not an attack on Crestron, I think Crestron products are great, don’t have a bad thing to say about them. I just couldn’t resist the infinite number of possibilities for the ultimate puns and practical jokes in this particular situation.

I so desperately hope that the programmer had the foresight to make the main navigation page resemble the “blue screen of death” and that he also had the sense of humor to make the reset button that returns everything back to its default settings in the event of a crash a brightly shining apple tucked neatly in the corner.

by Jason Levert

MISCONCEPTION or DECEPTION?

DECEPTION or MISCONCEPTION?

So often in today’s market we see myths or trends develop that actually are rooted in truth. Sometimes the truth gets skewed ever so slightly and I truly believe that the majority of the time it is done unintentionally. I’ll attempt to explain what I mean here. A lot of times a statement is made that is based on factual information founded in the laws of physics or principles of electricity so on and so forth.