do you really need 4 volts??? - - dont think so

 

uhh yes you do, most new audio recordings are done at 4v - 6v levels on the CD some rap CDs even use 8v. that means you are losing sound with your crappy 2v output and amp gain turned way up.

They dont make higher voltage outputs for nothing, they are really important to sound tuning (not so much to bass) but for SQ.

 

Just remember that just because something says 4V doesnt necessarily mean its 4V. Just like that fleamarket amp that says 4000WATTS for $79.99

 

dude i want a 4000 watt amp for 80 bucks...

 

are you calling kenwood a liar?

 

im pretty sure they are, you can hear a marked difference in the audioble output of your amp between a 2v and a 4v deck.

 

If there is that much difference in SQ I would think they would just use 4 v - how much difference would it cost to build - pennies!!!!!!! Alpine probably has more decks in competion systems than anyone else. I dont think they would skimp on something that important

 

... have you SEEN their new decks?

they have ONE with 4 volt preouts, and it's a damn dvd deck that no one carries. every cd player and dvd w/ a monitor is 2v. seems to me they're moving away from competition and becoming last year's pioneer. retractable volume knobs, oel display... come the fuck on.

 

Not saying you're wrong, but do you have anything to document the voltage levels CD's are recorded at? I'm curious as to what that exactly means.

I'm also not sure how you would lose sound quality SOLELY because you played it back at a different voltage than it was recorded at.

What higher voltage outputs let you do is get the signal above the noise floor. This is what is called signal to noise ratio. All the electronic goodies in your car make noise. Depending on the shielding, this can be loud or quiet noise, and can make it into your RCA's, where it looks like sound to your amp, which will reproduce it. Say this noise looks like a .05 volt signal to your amps. If your headunit only puts out .5v, this is only a 10:1 SN ratio. Kick the output up to 4v, and you have 80:1.

The bigger part of this problem is when the volume is down. Since 4v is a maximum at full volume, normal listening levels are much less than 4v. Since volume is a log10 function (not linear) 1/2 volume is actually .4v, not the 2v you were probably expecting. Take the .5v example, and your down to only .05 volts...right in the noise. This is why some systems have gain hiss...that noise you hear when the headunit is turned all the way down. Many headunits actually mute the output completely at very low volumes, so you can't hear this. Many test discs contain zero bit tracks...digital silence, that you can 'play' at any volume. This is where all the ugly noises you don't think you have surface. They are always there, slightly clouding your music, you just don't notice them. This is also about the only way to isolate noises coming from the headunit, as they will be volume dependent.

Now, look at the amp gain. You set this so maximum output comes somewhere near maximum input. This becomes the sensativity of the amp. The higher the input, the lower you set your gain, the less sensative your amp is, the less that pesky noise floor gets reproduced.

Back to your statement about playing back a 4v CD at 2V. I believe that in the absense of noise, as long as you match the gains on the amp to the output of the headunit, sound quality will be the same. Its not like your compressing the dynamic range by going to a lower voltage, as the peaks and valleys of the music are all relative. That being said, I don't know everything, and if you have data showing this, I'd love to see it.

Now, do 4V units really put out 4V, maybe. I think this would depend on lots of things, like the input impedance of whatever it is driving. Also, where is the 4V measured? At the board? At the end of the pigtail? Wherever, I doubt it will still be 4V at the end of a 20ft RCA.

In any event, more voltage is better than less voltage, provided you don't exeed the inputs on the amp. Even then, you'll just end up not using the top of the volume scale.

Toby

 

I've never really been a fan of Alpine amps. Actually, the only Alpine piece I really liked was the old 7909. Lately, they just look like any other big box piece. I unfortunately see JL heading down this road.

Class D is an interesting choice. Switching speeds have gone way up, so they can get pretty close to the original wave shape. Funny how everyone wants digital audio, but then the CD player samples it so much it looks analog again. Then, a Class D turns it back into something digital, and people complain. I'd bet that most people won't hear the difference over a class AB, and what you gain in efficiency makes up for it, at lest from Alpine's perspective. What is kind of surprising is the regulation...no power increase at 2 ohms. Not sure why they would do that.

I think with smaller cars and less electrical system headroom, combined with consumer price pressure (and the overall lack of demand for real sound quality) class AB as we know it will start to fade away. The good news is that with competition, some of the new technologies (Rockford Hybrid, Class G, Class T, etc.) may make it so we don't miss it.

Toby