Buck Mustard

I have 2 amps and they both have low pass/high pass filters on them.

I am wondering if people find these acceptable or if electronic crossovers which are far more adjustable are preferred?

Assuming the external crossovers are preferred, what are the characteristics to look for to find a good one?

Jim85IROC

iTrader: (2)

As long as you don't need options/flexibility beyond what is available on the amp crossovers, just save yourself the money and use those. There won't be an audible difference between an amp's 12dB/octave crossover and an external one. External crossovers usually offer the benefit of extra flexibility in terms of output channels and filter frequency. Many of the better ones also use steeper filters.

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REZN8R

Another cool feature is some crossovers will boost your output signal voltage to your amps so you can get a cleaner signal and not have to turn your gains up as much to get the same output.

Buck Mustard

Does a crossover go between the source and the amp

- or -

does it go between the amp and the speaker?

Jim85IROC

iTrader: (2)

It depends on what kind of crossover. A passive crossover would go between the amp and speaker, but it wastes power and is not really a terribly accurate device unless it's designed in a such a way that it winds up being real inneficient. It's also non-adjustable.

An active crossover is one that manipulates the signal before it is amplified and does so with op amp circuitry so there is no signal loss. They can also be adjusted, unlike passive units. They make passive units that are designed to be used before the amp, but they're all crap.

Having a crossover boost the signal is basically worthless unless there is a very large distance between the crossover and amp.

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REZN8R

Alright, usually I just assume you know what you're talking about, but this just sounds wrong. If boosting the signal is useless, then why do a lot of good companies make line drivers? Their only function is to boost the signal voltage. Since most cars are roughly the same length from deck to trunk, I don't think the distance has a whole lot to do with it. Also, why would good decks come with a higher pre-out signal voltage? You've got a bunch of explaining to do to back up that statement man.

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Jim85IROC

iTrader: (2)

1. Companies make them because people buy them.

2. There are only 2 benefits to a higher level signal. The first is better noise isolation, but if your crossover is right next to your amp, it's useless. I don't know many people that mount their crossovers to their dash boards. The second is the ability to lower the noise floor of the amp. This is quite valid, but only if the crossover has a lower noise floor than the amp, which isn't real likely.

------------------
The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

REZN8R

I guess I'm thinking more in my case where I'm using a 1/2 din parametric EQ/crossover which boosts my signal from the deck's 4 volts to 13 volts before they make the 16 ft journey to the amps. I've always understood that a higher voltage signal means a cleaner signal. Like you said that would mean noise isolation and also a lower noise floor. But I also thought that a higher voltage signal would effectively give you more volume before the amp. When you turn up the gain on a crossover you can turn down the gain on the amp and get the same output. Isn't turning up the gain on the crossover just increasing the voltage of the signal to the amp?

REZN8R

I guess I could just E-mail you about this stuff, but this way everyone can be enlightened.

Jim85IROC

iTrader: (2)

A higher voltage from a pre amp that's up front is considered a good thing, I'm not denying that. I just find it fairly useless on an external processor that gets mounted in the trunk right next to the amp. Anyway, boosting the voltage does lower the noise floor and help reject noise, but it's an absolute minimal amount. Sorta like the difference between 600 horsepower and 600.05 horsepower. With a 2 or 4 volt pre out, you're already dealing with a very clean signal, so there is only minimal room for improvement. In a competition system where judges specifically listen for any audible amount of noise, it *may* make a difference. In any type of real-world situation it's a waste of money.

A higher pre-out voltage will not make anything louder. Your amp is only going to reach a predetermined maximum output regardless of how much voltage you feed it. In order to keep the input stage of that amp from going into clipping, you need to trim the gain back on that amp. In doing so you lower the noise floor of that amp, but you in no way get any sort of additional output from it.

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The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

REZN8R

Thanks for clearing that up.