Originally Posted by Vomitor
I am interested to know some of the major tonal quality differences between active and passive. As I read the active ones have more punch, I guess due to the higher output power caused by the battery? I checked out the Ibanez yesterday and most all of them had passive pickups. I also saw some paul reed smith's, one which was even fretless that looked pretty cool. I played a few warwicks but noticed that the way it was constructed it would be almost impossible to play from around the 22nd-24th frets. It may not be that important, but why bother designing it with that many when it's practically useless unless you do some special technique. Does wood affect the tone in any way? I am looking for something as I said for metal, but would like also for it to be able to have a nice warm sound for melodies.
Ok, get ready for a bit of a read....
The first thing you need to know is the differences in construction between active and passive pickups. A pickup at its most basic is a set of magnets, either ceramic or alnico (aluminium, nickel, and cobalt) with wraps of copper wire around them. When the metal guitar or bass string above the pickups vibrates its changes the magnetic flux of the magnet and creates a voltage in the copper wire wrap around it. This voltage then passes through your pots and can be manipulated by your volume and tone controls or by an active preamp, which can introduce different frequencies into the signal before it leaves the instrument through your cable.
Now, to understand the difference between active and passive pickups you also need to understand the effect that different amounts of copper wire wrapped around the magnets has. More wraps of copper wire = higher output, fewer wraps = less output. BUT, you can only use so many wraps of copper wire before you start making the pickup extremely sensitive to outside factors (Radio frequencies, lights ect..) which will cause the pickup to be very noisy and generally unusable, plus this begins to blur the midrange. So creating the perfect balance of wraps, output, tone, and resistence to interference is very much an art. This is where active pickups come in...
Active pickups employ much much fewer wraps of copper wire, making the pickups completely noise free. But what this does is creates a very very low output, so a small preamp is built into the pickup to boost the ouput, this is what the 9 volt battery is responsible for powering. This design however is looked down upon by purists for a handful of reasons.
Passive pickups (good ones) sound natural, they let your various styles and playing nuances show through, they allow for much more control over your tone simply by changing the way you play. Active pickups, due to the internal preamp, tend to be less dynamic, meaning that they lend themselves to having a basic sound that cant really be changed through various playing techniques. This is because when you play, your signal will be boosted by the preamp in the pickup regardless of how you play. Now bear in mind, that basic sound can still be a very good tone that someone may prefer.
Another thing of course is basic tone, this is where I think active pickups have their fault. The use of more wraps of wire in passive pickups results in a natural tonal curve, typically emphasizing the lows and low mids a little more (bear in mind this is with soapbar or humbucker style bass pickups, J-bass and P-bass pickups are a completely different story). But active pickups, with their fewer wraps of wire, have a very flat tonal curve, giving equal presence to all frequencies. This sounds good at first, but then you have to realize that certain frequencies are more harsh to the human ear, (1khz-3khz range) and since the frequency response of active pickups is very flat, these frequencies will now stand out much more. This is what gives active pickups, especially cheap ones, that bright clanky sound. Now if you like that sound, thats great, but most people dont.
Another thing is how the instrument itself lends to the tone. Passive pickups (again, good ones) draw influence from the woods of the instrument, this is why high end bass companies like the ones I listed in my previous post use passive pickups, because these companies use high quality tone woods in their construction and want to take advantage of the tones these woods have.
Active pickups, especially for bass, dont really care what the instrument is made out of. An EMG bass pickup will sound the same no matter what bass you put it on, unless of course the strings are completely different, those will still always effect tone. So active pickups are great in cheap instruments that arent made of quality materials, but are a bit of a waste in higher quality instruments.
Now of course there are exceptions, Alembic makes a very natural sounding active pickup and Ibanez makes some super shitty sounding pickups. When it comes to this use the old rule "you get what you pay for".
There still are advantages to active pickups. Given that they have a very flat tonal curve, they respond well to an active preamp. With a good active preamp, you can draw a wide range of tones from active pickups. Although some people still think that doing this sounds unnatural. This is why the combo of a high quality passive pickup (Bartolini's, Villex, Seymour Duncan's) and a high quality active preamp is popular. This gives the natural tone of passive pickups with the flexibility of an active preamp.