[Mark T. Montgomery]

Hey guys I have another question.  What exactly are crossovers and preamps and how do they work.  What do you conect them to and stuff like that.  Is a preamp the same as a receiver, and how do crossovers hook up to your amp??? Again thanks for your help.

[Rob Babcock]

A crossover is a device that divides the musical signal into distinct frequency bands so that one part is fed to each driver.  For example, a two-way crossover would typically send the low freq stuff (ie. bass) to a woofer and the high freq stuff (ie. treble) to a tweeter.  This type of device could be two-, three-, or four-way.  

A crossover designed to filter out bass is called a high pass.  One designed to feed a sub is called a low pass.

Crossovers can be passive or active.  A passive crossover, like the ones in you Cerwin Vegas, is composed of caps, resistors and other parts soldered to a circuit board.  The signal from your amp or reciever is divided up inside the X-over (that's 'crossover') to feed the individual speaker drivers.  An advantage of this type of X-over is that they're cheaper to build than an active one, more compact, and require no tweaking by the user.  A drawback is that they cause some of the power to be lost.

An active X-over is an electronic device inserted into the signal path before the amplifier stage.  It does the same thing, but with low level signals.  Active X-overs are often more flexible, as they often can be adjusted.  The downside is the added cost, complexity and space required.

Lastly, X-overs are often catorgized by the "slopes" of their individual 'legs'.  For instance, a "First Order" X-over has a 6 dB per octave slope for a very gradual transition from one to the other.  The differences in the "orders" of crossovers is a bit more advanced than we'll want to get here, but it greatly affects the performance of you system.

[Rob Babcock]

A reciever can be thought of as three stereo components rolled into one and placed in one box:  they comrise an Amplifier, Preamp & Tuner.

The Amp takes a low level signal and increases it to the point that it can drive your speakers.  A tuner recieves the AM & FM radio signals and converts them to a signal the preamp & amp can use.

The preamp section is the heart or 'brains' of the system.  It switches between different sources (eg. the CD player, radio, or tape deck).  It also controls the volume, tone controls (like bass, treble & loudness), and feeds the amplifier.

In a standalone preamp, the unit does only the last catagory of things.  The advantage of a separate preamp over a reciever is that you can choose each section to best meet your needs.  For example, if you have a very basic system, you can get a bare bones preamp and buy whatever amp you like.  And if you later move to a larger room or buy power hungry speakers, you can upgrade just the amp and keep your existing preamp.

Performance is generally better, too, when you separate all these functions into theri own box.

[Mark T. Montgomery]

Thanks man.  Now I understand how that works.  As for the preamp stuff, does a preamp simply act a signal increaser or amplifier.  Just like a reciever except a reciever also handles stuff like Bass boost, surround processing, and DTS?  Also does a preamp keep the signal digital or does it convert the signal to analog (which wood be a wasted conversion if you plan to use any kind of bass, treble or loudness boost in your reciever) which.

[Mark T. Montgomery]

Thanks again man.  This has been the most helpful Forum I have ever been a member of.  I could weeks in the Smr forum and no one would answere my posts.  It seems to me that in a lot of audio forums the members think they are to good for you if your a newb and won't help in any way.

[Rob Babcock]

No prob.  Lots of sites don't want to help new guys out, but they forget that once they were newbs, too.  That's why I started this Circle.

Now, in strict terms, a preamp is usually thought of as only handling analog signals.  A preamp that can handle DTS, Dolby Digital etc is generally called a "preamp/processor", or "pre/pro" for short.  This can be thought of as a reciever without the amp sections.  A prepro will usually cost more (due to image, lack of economy of scale, and higher parts cost) but can sometimes offer better performance.  You also get the advantage of being able to buy however much amp you need, be it a 5 Channel amp or several stereo or monobloc amps.

Like a modern HT reciever, a Prepro will accept a digital input and perform all the signal manipulation (eg volume, bass, treble, speaker distance, etc) digitally, converting to analog only at the amp stage.

A new type of reciever, the Digital Reciever, will actually pass the digital signal to an all digital amp.  This is a relatively new concept- sending digital power pulses to power your speakers.  The pulses are short enough and fast enough that they sound continous to your ears.  This is a little beyond the scope of your question but it's pretty cool!

In short, yes, a preamp can control bass, treble, volume and what source you're listening to, but it doesn't have amps built in.  

BTW, if you leave out the tuner but add amps to a preamp you get what is called an "integrated amp."

[Mark T. Montgomery]

I've heard about this fully digital amp stuff before.  I figure that in a few years analog amps are gona be trash compared to digital amps.  Anyway it sure would be great if this turned out to be the leap forward in terms of quality and performance.

[lonewolfny42]

Thanks again man.  This has been the most helpful Forum I have ever been a member of.  I could weeks in the Smr forum and no one would answere my posts.  It seems to me that in a lot of audio forums the members think they are to good for you if your a newb and won't help in any way.

AudioCircle members are a great group. Need an answer , you get it ! Stick around , lots of excellent info in each circle !