Entertainment systems / Audio?

I'd like to thank this thread for reminding me of the not so good times selling car audio. Wattage means very little, but the cheap manufacturers use it as their sales line. I used to sell the soundstream reference 405 that was 25x4 and 100x1. 200 watts total that rocked every car we put it in. Clean RMS power, there is no substitute. How do awesome car audio companies go under while flea market brands like pyramid keep kicking, I'll never understand it.

 

Because people like to see big #s and think they got a deal then wonder y it blows every month

 

I didn't say that the speaker was overdriving the amp. You are overdriving the amp by having the volume turned up too far.

I took a quick look at Crutchfield, and they have a Jensen mono amp rated for 400W. 400W into 2Ω, 1% THD (total harmonic distortion). It also lists "max power" as 900W; that's likely driven to clipping.

If the amp clips at 900W into a 2Ω load, we know enough to figure out the other two variables of Ohm's Law.
P=power in watts (900W)
E=voltage in volts
I=current in amps
R=resistance in ohms (2&#937

P=I*E and E=I*R. Substitute for E, and P = I*I*R; regroup and I*I=P/R; I=sqrt(P/R). I=sqrt(450) ~= 21.2A.
E= P/I ~= 900/21.2 ~= 42.5V. (~= means "about equal", due to rounding.)

For the sake of the calculations, let's say that the amp clips at 43V.

Note that these measurements are made using a nonreactive 2Ω load; basically a carbon resistor. A speaker coil is anything but a stable 2Ω; its impedance varies with frequency (among other things). It may show a 2Ω load when given a 100 Hz sine wave; it would then drop to somewhere around 1Ω at 50 Hz. Give it a DC voltage (frequency zero), and it'll drop to near 0Ω; what's left is the inherent resistance of the wire the coil was wound with. Let's say that if you measured from the point where the speaker cables attach to the amp, you had a DC resistance of 0.5Ω.

Now for the roller coaster ride...

We know that the amp will deliver 43V at clipping. When the amp is at clipping, it is sending out 43V DC during the clipped part of the cycle. How much power is that?

P = I*E and I = E/R; so P = (E*E)/R. P=(43^2)/0.5 = 3698 Watts. Yes, that's a very brief transient, but if you have the amp cranked, that happens A LOT. The damage is cumulative. So basically, your speaker dies the death of a million paper cuts.

It's after midnight, so here's hoping that Amp/Speaker Integration 101 (with a little Electrical Engineering thrown in) was, for the most part, intelligible.

 

Without advertising, are there any recommendations for a system that would include:

1) Direct input for Ipod with integrated controller (should also charge Ipod)
2) Direct input for Satellite radio receiver
3) Bluetooth for wireless phone with charger for phone


I don't do CD's anymore, so I do not need a CD deck; but for sleeper time, a small TV/DVD player/streaming device would be cool, I am thinking a 32" screen?

 

interesting thread!

 

Try listening to better audio, classical music sounds great on stock sound systems, I'm tellin' ya, I got the sextets to blow my hat off while roaring down the road, with the windows open. Coincidence? I think not.

 

I am sorry, classical music literally puts me to sleep. It's what I listen to when I want to sleep.. Not so much a good thing when I am in the driver's seat!

 

Chamber music is generally louder and less lulling than symphonic recordings, FYI.

 

I have 9800 tracks on my Ipod... If I didn't randomize the playback; I could listen to it for 26+ DAYS straight and not hear the same track twice! No commercials!

 

Yea...I'd like to see a guy rolling down a hill with his music up so loud that the bass mufles the sound of his trailer wheels grinding on pavement