Is This Normal? Or Even Logical? Negative numbers show the amount of attenuation that the volume control is applying to the amplifier. Control Volume by Restricting the Signal Once you get a handle on the explanation, it makes sense. In addition to the amp and attenuator, every single part in an AV receiver affects sound quality, such as the high grade parts used in Yamaha units pictured above L to R : custom made block capacitors, extra-large power transformer, schottky barrier diode, large size speaker terminals and high quality parts.
Negative numbers mystery solved! Keep reading. In the next article we look at how to read the specifications about decibels, before looking at some real world applications. This article is based on one I originally wrote for my friends at CamcorderUser. This site uses Akismet to reduce spam. Learn how your comment data is processed. Contact Geoff: geoffs geoffthegreygeek.
Sign in. Log into your account. Forgot your password? Privacy Policy. Password recovery. Recover your password. Understanding Audio Understanding Amplifier Power.
Amplifier power is probably the most misunderstood and abused parameter of amplifiers and speakers. Yet, it is often the first and possibly only parameter Understanding Audio Understanding Speaker Sensitivity. Speaker sensitivity is a measurement of how well a speaker converts the amplifier power to to acoustic energy. In others words, how loud the Often people are wanting to add speakers to their amplifier to increase power.
However, in most cases, adding speakers will reduce the power in Speaker impedance changes amplifier power output. In fact, your amplifier power could be nearly half or double its capacity - depending on the impedance Home Speakers Understanding Speaker Impedance. Speaker impedance is often presented as a complex subject and therefore is either ignored or misunderstood.
A basic understanding of speaker impedance is not Distributed speaker systems are also known as " volt line" or "70 volt line" speaker systems. They are used extensively where multiple speakers are Understanding Audio Double amplifier power does not double the volume. This article logically shows the relationship between amplifier power, SPL and loudness. It includes a level difference exercise and a gain calculator. Understanding Audio Understanding Acoustic Feedback.
Acoustic feedback it that annoying loud continuous tone you get when the sound system is not set up or operated properly. Acoustic feedback can Understanding Audio Understanding Audio Frequency. Every sound we hear is at a certain frequency. When we say someone has a deep voice, we are describing a voice producing low Understanding Audio Understanding Decibels part 2.
In the first article we saw that a decibel is not a fixed unit, rather, it is a ratio between two levels. A decibel Understanding Audio Understanding Decibels part 1. But first, some Understanding Audio Understanding Audio Levels.
A basic understanding of the general audio levels mentioned in this article will help you avoid the common mistakes often made when connecting audio Understanding Audio Understanding Microphone Sensitivity. What do you understand about microphone sensitivity? Of late I have seen a number of people miss-interpret the specifications of microphones, especially when it After answering nearly questions on connecting speakers on this website, some common themes have emerged.
Please read the answers to these Frequently Asked Questions The speaker selector switch simulators presented here demonstrate how speaker selectors deal with speaker impedance and power distribution.
Speaker selector switches are used to In this article we look at how and when to connect 2 speakers in parallel or series. Both the theory and practical points on Speaker selector switches are the most common item bought from Amazon through this website with over units sold. Therefore I thought it is Calculators Speakers in Parallel Calculator.
Jump Straight to Calculator The calculator below is useful in determining the total impedance of speakers in parallel. It also calculates how the power is In an earlier article we looked at the issues involved in connecting multiple speakers to one amplifier. In this article we look at some I am often asked "How do I connect multiple speakers to my amplifier? You may still have many video tapes that you like to play but find it hard to connect a VCR to your new flat The recent passing of Eugene Polley, the man known for inventing the remote control, has given me cause to reflect on the development of It works similarly to a VCR, but This is the summary of the previous five articles looking at the different video signals and connectors commonly used in Home AV.
Previously we Connecting your TV is not as hard as it looks. All the sockets on the back and up the side of a flat screen This is the In this article, we look at component video signal: what it is, where it is used, and what cables are used for component video In this article we look at RGB video signal: what it is, where it is used, what cables to use and the problems with In this article we look at S-video signal: what it is, what cables to use, where S-video is used and the problems with it.
Do phone chargers and Ipod chargers draw power when not connected to their device? The answer is: it depends on the type of charger. Depending on the mix, it's easy to fatigue your ears at I haven't needed more than dB so far which is quite loud , but I was curious what the designated dB level meant.
Especially since most modern recievers have a "virtual volume-knob" that doesn't have a fixed reference point. The know doesn't have a point where it starts and ends, it turns indefinitely. So if the reciever sets the minimum sound level at dB, then 85dB would be at 0? If so, that's quite loud, and I couldn't imagine listening to movies at that level. I haven't been over dB on the DVD source, and that's loud enough to annoy the neighbors Understand that the scale used by a THX-certified reciever and your particular unit may not be the same.
IOW, 0 dB on that reciever may correspond not be same value on your reciever. Not sustained volume levels, but peaks. It also specs. The point of the -xx dB system is to calibrate first, usually to reference level so that when you get to 0, you are at reference level, i.
Before calibration, you don't really have any idea what the volume setting represents in terms of actual output. You can calibrate using something like Avia and a SPL meter, or if your receiver has an auto-setup feature and mic, it will do it for you. Google brought up this and this. Have a read. The 85dB reference level for THX calibration is with a noise source, so yeah, peak would be higher.
On the flip side, I believe TASA regulations limit the peak volume of movie trailers shown in a theater to 85 so that studios can't try to out-do each other when promoting their wares. Just a bit of trivia. If the reference is 1mW into Ohms A dBu is a potential unit, while a dBm is a power unit.
The scales are meant to be "equal" for a Ohm load; 20 dBus across a Ohm load yields 20dBms. Dan and xevion have it right as far as dB short term peak level for the mains channels and dB for the LFE.
I believe THX copies these reccomendations, but has additional qualifications for radiation patterns, etc. The 85dB is just a target for dialog levels in cinema. Of course individual movies are free to vary this. I find I watch with the typical level around 75dB as well, so most likely dB below reference. I keep stating around here that most people need less amp power than they think I'll get peaks over dB at that. I get the feeling that the average 85dB at reference doesn't quite follow in practice, i.
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