Audio! This subject is my life. I used to eat a breath it. I was at the top of the feild in sound design.
OK, first rule
of life. The HiFi audio world is full of snake oil
, hens teeth and flying pigs, all sprinkled with a fairydust and served with a gravey of BS.
Your responsability?=don't be easily suckered by the sales guy.
OK, on to the task. I will try and keep this concise, but it will still be long.
First question is, just what do you want to spend. You can go mad. I can sell you speakers that will cost you around US$60K. Quite frankly I think they are crap when compared to the price. But you can also go bargan basment as well. It is also false economy.
Several here have already suggested not to go 12V. This is true if you are looking at power. To get Power from 12V, you have to have internal inverters in the circuit. You pay for that. So reputable brand name high end car audio is usually expensive. That then brings us to the point of power. How do you measure power. You will see many of the following.
RMS @ 10% distortion
RMS @ 1% Dist.
RMS @ 0.05%
Peak to peak music
What does all the above mean? Well actually, absolutely nothing. Although the RMS ratings are more realistic, none of the above actually tell you how they were measured.
Most HiFi amplifiers will give you figures that look impressive but mean absolutely nothing.
Oh and sorry guy's, Weight means totally nothing. The weight comes from the mains AC transformer. The heatsink weighs nothing and I'll come back to that. The conventional mains transformer Power supply is cheap
. It is also highly inefficient. If you want the best, a solid state switching supply can't be beat. But unfortunately, the industry has dished out a pile of crap about weight equaling quality.
Back to the heatsink. The heatsink gets rid of heat. The heat is produced by the output circuit design. Some designs are more efficient than others. A big heatsink can also mean a cheap design.
I have a commercial
high end audio amplifier that can produce a total of 2KWRMS at 0.001% total harmonic distortion measured from 20Hz to 26Khz and it has no heatsink and no fan. It is in a totally enclosed case.Expensive, but I used them in clubs and such were there was a lot of dust dirt and grime from tobaco smoke that would cause a fan type amp to packup in a month.
Matching amplifier to speakers. The correct way is to go double the amplifier power to a speaker. Once again, you need to know how the manufacturer has rated there speaker. The same issues as the amplifier power further above, apply. So lets say we have a speaker that is 100WRMS rated. In theory the amplifier should be 200WRMS. You will never turn the amplifier up that loud. It allows a thing called dynamic headroom
. Let me go back a step. You know how some of the purests rave on about the old records sounding better than a CD. Well this is all about compression
of dynamic music peaks. This is a form of distortion and is why you also complain about TV adds sounding louder than the normal broadcast. Actually it isn't. The add is highly compressed and gives us the impression that it is louder. This problem when listening to music equats to listening fatique and "noise". Being able to reproduce dynamic peaks allows the music to "breath". sorry, I just can't find anyother word to describe it. But you hear detail that you don't in a compressed source. OK, this is the scary part. Dynamic peaks can be as high as 10dB above the main level. Even on a CD, especially todays stuff as Digital has come along way. To reproduce a peak of 10dB, you need an amplifier that has a peak ability of 10 x the main RMS programme material. So you actually need 1000WRMS amplifier to run those 100W speakers. Of course, that ain't going to happen, but it is why a more powerful amplifier sounds better.
The next point is cliping. This is when the amplifier can no longer reproduce enough of the peak content. It has run out of what is called "headroom". It cuts of the tops of the waveforms.This is death to any speaker. A 50WRMSamplifier run into clipping will fry a 2000W speaker in minutes or even less. Clipping is the distortion you hear when it is truned up to loud. C-rap seems to love distorted bass.
How loud will it all go. Well actually, this has little to do with the power output. Our human hearing works like this. The smallest sound for someone with perfect hearing can discern is called 1dB. Decibel after Mr A Bell, the telephone dude.
3dB is considered the amount a sound has to increase for us to percieve an increase in level. 10dB is the amount of sound pressure we persieve as twice as loud. An increase of 3dB, requires twice the power. So to turn up a 10W amplifier and "hear" an increase, requires 20W of power. To "hear" it as twice as loud would require 100W. So what makes a speaker loud. It's called it's Effieciency and is measured as the following.
"x" dB@1W/1m. A good Hifi speaker may be as efficient as 80dB@1W/1m. This means that if you measure the sound level from a distance of 1metre, place 1watt of sound energy into the speaker, the measurment will equall 80dB. Indoors, a rule
of thumb is that for every doubling of distance, that sound level will reduce by 3dB. Outdoors it is -6dB. Most people listen to music around the 90 through to 100dB. A loud rock concert can be about 110dB upto the earbleeding levels of 130dB. The loudest concert I have mixed for peaked at 121.8dB. That was damn loud.
I have a pair of top end commercial
speakers here that have a sensitivity of 106dB@1w/1m
The sensitivity rating is probably the most iportant measurment that can be made. When it is measured along with the frequency plot, it tells you everything you ever need to know about the speaker. No wonder vertually no one in the HiFi world ever produce or publish that figure for there speakers. Or if they do, they publish it such a way, that it makes no sense.
Interconnects. These are the cables
that connect your equipment
together and the power cables and the speakers leads. Thsi is where I have found the biggest pile of crap in the industry. You can if you are easily parted with you money
, payUS$300ft for speaker cable and audio signal cable. I even know if a 4ft power cable that sold for US$4500. I have close freind that produces audio cable for the commercial industry. When he started out, he wanted to be the best in the world. So they decided to look at who they wereup against. So they went and bought all sorts of cables from everywhere you could imagine and all the prices you could imagine. They had very sophistcated measuring equipment. After all the test were made. the conclusion was, some of the best cables measured were el'chepo's from your Radioshack. Don't get fooled by cables that have arows printed on them because the electrones flow better that way. Yes it's sold. It's called directionalised copper cable. OFC (oxygen free)copper is another one. Now we all know what happens when metals, especially copper gets oxygen in it. Metals oxidise and copper becomes useless at conducting. Yes it's true it is OFC, but all copper wire is unless it is stuffed.
OK, that does it for now. I can goon and on and on and on an.....
But I can just imagine all your eyes glazing over.
Oh, poly cones can be water resistant. But you have to ensure ll the speaker is. Corrosion
is it's worst enemy. But poly cones sound plain awefull to me. Paper cones still sound the betterand can be made water resistant. Just spray the silicon sail slide lightly over the face of the cone. It works reall good.