Crossovers, receivers and sound quality - AVS Forum
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post #1 of 22 Old 04-25-2012, 04:35 PM - Thread Starter
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It was said in many of the threads (I will find those later) that the receivers have no impact on sound and that speakers drive the sound quality (warm, laid back cool, etc). Granted.

Then in some threads I see that crossovers in the speaker affect the sound quality and that there are aftermarket crossovers available with upgraded electronics to improve the sound. Even Definitive Tech. boasts of upgraded crossover components in the newer SM45 bookshelf speakers.

Then I have to ask the question: Even receivers have crossovers and most of the electronics found in a passive crossover. Do they really have no impact on sound quality?
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post #2 of 22 Old 04-25-2012, 07:00 PM
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1. The crossovers in the AVRs are active, electronic and, often digital, and the ones in speakers are passive using different types of components.

2. They perform different functions as the crossovers in AVRs are concerned with rerouting the bass from the main channels to the sub(s) as part of bass management. The ones in the speakers divide the spectrum among the drivers within the box.

Everything has some impact on sound quality.

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post #3 of 22 Old 04-25-2012, 07:15 PM - Thread Starter
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Thanks for the response Kal.
The crossovers in the AVR are active, but it still needs electronic components to separate the frequencies. so in some shape or form they are modeled after the passive crossovers.
The ones in the AVR separate the low and everything else. The ones in the speaker separate the high and mid-low. Not much difference there. Or is there?
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post #4 of 22 Old 04-25-2012, 07:17 PM
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Quote:
Originally Posted by chikoo View Post

Thanks for the response Kal.
The crossovers in the AVR are active, but it still needs electronic components to separate the frequencies. so in some shape or form they are modeled after the passive crossovers.
The ones in the AVR separate the low and everything else. The ones in the speaker separate the high and mid-low. Not much difference there. Or is there?

Yes, there is.

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post #5 of 22 Old 04-26-2012, 03:56 AM
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Your choice of speakers have the most impact on the sound. AVR's, amps and other components have far less impact on the sound. Room treatments will have a large impact on sound quality as well.

Dumb enough to spend lots of cash on this junk!
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post #6 of 22 Old 04-26-2012, 05:38 AM - Thread Starter
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I am trying wrap my head around the idea that the capacitors in a passive crossover affects sound quality, then why AVR / amplifiers which contains such electronic co.ponents and more is generally not considered affecting the sound quality.
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post #7 of 22 Old 04-26-2012, 06:19 AM
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Quote:
Originally Posted by chikoo View Post

I am trying wrap my head around the idea that the capacitors in a passive crossover affects sound quality, then why AVR / amplifiers which contains such electronic co.ponents and more is generally not considered affecting the sound quality.

Because they operate at difference impedance levels, the choice of materials is different. Also, you are overthinking minor issues.

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post #8 of 22 Old 04-26-2012, 06:54 AM
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Quote:
Originally Posted by chikoo View Post

I am trying wrap my head around the idea that the capacitors in a passive crossover affects sound quality, then why AVR / amplifiers which contains such electronic co.ponents and more is generally not considered affecting the sound quality.

The size differential of the caps used in passive versus active is huge, on the order of 1000:1, and so can be the cost. It's a lot less expensive to get a good quality 0.1uF cap than 100uF. Also, most receivers today don't use caps in the crossover anyway, it's performed by an integrated circuit.

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post #9 of 22 Old 04-26-2012, 08:48 AM - Thread Starter
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Quote:
Originally Posted by Bill Fitzmaurice View Post

The size differential of the caps used in passive versus active is huge, on the order of 1000:1, and so can be the cost. It's a lot less expensive to get a good quality 0.1uF cap than 100uF. Also, most receivers today don't use caps in the crossover anyway, it's performed by an integrated circuit.

And an IC contains Transistors, Resistors and Capacitors integrated within. Doesn't that affect sound quality?
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post #10 of 22 Old 04-26-2012, 08:59 AM
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AVRs crossover are digital...
So we have drifted to ICs used outside of filtering?

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post #11 of 22 Old 04-26-2012, 02:07 PM - Thread Starter
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Quote:
Originally Posted by psgcdn View Post

AVRs crossover are digital...
So we have drifted to ICs used outside of filtering?

Yes and No. The sound is filtered in the AVR using an IC, and is processed/amplified using a few more. Wouldn't the make, model of the IC make a difference to the sound quality?
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post #12 of 22 Old 04-26-2012, 02:12 PM
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No, because the filtering in an AVR is done entirely in the digital domain and not on an analog signal (as in a speaker crossover). You can't think of the filters as software.

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post #13 of 22 Old 04-26-2012, 02:22 PM
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Quote:
Originally Posted by chikoo View Post

And an IC contains Transistors, Resistors and Capacitors integrated within. Doesn't that affect sound quality?

ICs contain resistors and capacitors within? You sure about that?

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post #14 of 22 Old 04-26-2012, 02:36 PM - Thread Starter
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Quote:
Originally Posted by beaveav View Post

ICs contain resistors and capacitors within? You sure about that?

Sure looks like it. The little grey blocks are capacitors.

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post #15 of 22 Old 04-26-2012, 02:39 PM
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Quote:
Originally Posted by chikoo View Post

Sure looks like it. The little grey blocks are capacitors.


And those are "within?" Nope. Those are external, and likely power supply filtering caps.

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post #16 of 22 Old 04-26-2012, 02:45 PM - Thread Starter
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now we are playing with semantics. It is still within the IC design.
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post #17 of 22 Old 04-26-2012, 02:48 PM - Thread Starter
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Not that I know this person making the post or his standing in the field, but definitely worth reading

http://www.physicsforums.com/showpos...73&postcount=5

Quote:
There are a couple of means of forming capacitors in an IC. Reverse biasing a circuit gives you a capacitor, though it's voltage dependent. A nicer variety is formed using oxide as a dielectric and either metalization or heavily doped silicon as a plate.

Capacitors are the basis upon which DRAM is constructed. By occasionally reading the potentials on a group of capacitors and then writing back to them, each one's state can be maintained as a 1 or 0 indefinitely. Of course, with the pressing need for denser and denser memory, the capacitors in RAM are no longer planer. Now, a special etch process actually drills into the silicon forming vast numbers of wells, which are then plated on the backside forming capacitors.

In analog, capacitors are commonly used in the op-amp circuit to establish what is termed the dominate pole. The dominate pole is a frequency, which is established by an RC, and serves to reduce the gain of an op amp versus it's test frequency. Typically, this frequency will be on the order of 10 Hz, and the open loop gain of the op amp will steadily decrease until it's = 1, at the op amps gain bandwidth.

Capacitors are also used in A/D converters of different sorts. It's remarkably easy to control the relative surface area on a chip, so it's easy to define capacitors as being an exact multiple of one another. This is the basis of the very common successive approximation converter. Capacitors are also used in building blocks such as the integrators in delta sigma A/D converters.

Surprisingly, you can even build the equivalent of resistors by using capacitors with mos switches. Thus dividing networks and filters can be fabricated without the need of resistors. The switching frequency and ratio of the capacitors set the properties of these systems.

There are actually quit a few more applications that inventive chip designers have thought up, but I'm sure this gives you a start.

Best Wishes,

Mike

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post #18 of 22 Old 04-26-2012, 02:49 PM
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Quote:
Originally Posted by chikoo View Post

now we are playing with semantics. It is still within the IC design.

Although I understand your point of view, it is absolutely not within the IC design. To a layperson, it may seem the same. To an engineer, it is not the same. There is a reason those caps are externally mounted and soldered to the IC, as opposed to being integrated within the IC.

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post #19 of 22 Old 04-26-2012, 07:05 PM
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Quote:
Originally Posted by beaveav View Post

ICs contain resistors and capacitors within? You sure about that?

But all it is doing is manipulating 1's and zero's. It's not fooling with an analogue signal. So if it takes the ones and zeros in and does nothing with them other than to direct their path and amplify the signal, then it won't do anything until it hits the DAC.

Dumb enough to spend lots of cash on this junk!
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post #20 of 22 Old 04-26-2012, 07:08 PM
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Quote:
Originally Posted by flyng_fool View Post

But all it is doing is manipulating 1's and zero's. It's not fooling with an analogue signal. So if it takes the ones and zeros in and does nothing with them other than to direct their path and amplify the signal, then it won't do anything until it hits the DAC.

Did you quote the wrong post? I'm having a hard time following how your reply relates to my post that you quoted.

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post #21 of 22 Old 04-30-2012, 08:23 AM
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Quote:
Originally Posted by beaveav View Post

Did you quote the wrong post? I'm having a hard time following how your reply relates to my post that you quoted.

Ya, I did. I should have quoted the OP.

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post #22 of 22 Old 04-30-2012, 08:54 AM - Thread Starter
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Quote:
Originally Posted by flyng_fool View Post

But all it is doing is manipulating 1's and zero's. It's not fooling with an analogue signal. So if it takes the ones and zeros in and does nothing with them other than to direct their path and amplify the signal, then it won't do anything until it hits the DAC.

Quote:
Originally Posted by flyng_fool View Post

Ya, I did. I should have quoted the OP.

This makes sense now. I was confused too
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