A typical and very common example would be using pro audio electronic crossovers, cheap and readily available, in home audio systems. Let's say, a pre-out in an integrated amp feeds a pro crossover, and the pro crossover then feeds home audio amps.
What troubles me is knowing that the pro electronic crossover is designed to work with stronger signal levels than the home audio gear. The crossover is expecting a stronger input signal than the home audio preamp can deliver. And the pro crossover is outputting a stronger signal than the home audio amp is designed to handle.
Below are comments relevant to my question, quoted from "Sound Reinforcement Handbook" 2nd Ed, 1989 by Gary Davis and Ralph Jones
"...line level phono jack inputs and outputs are intended for use with high impedance equipment, which is basically sensitive to voltage rather than power, so their nominal levels may be specified as -10dBV"
"Typical line level XLR connector inputs and outputs are intended for use with low or high impedance equipment. Since older low impedance equipment was sensitive to power, nominal levels were often specified as +4dBm or +8dBm, levels characteristic of sound reinforcement and recording..."
"A low impedance line output generally may be connected to higher impedance inputs without much change in level. Be aware that if a high impedance output is connected to a low impedance input, that output may be somewhat overloaded which can increase distortion and lower the signal level, and the frequency response may be adversely affected. In some cases, the equipment could be damaged....."
<end quote of Sound Reinforcement Handbook>
Would not connecting the pre-out of an integrated amp to the input of a pro electronic crossover be what is described in the last two sentences from the book, quoted in bold above?
Is using a pro electronic crossover with home audio amps and preamps, even though a common practice, less than ideal and potentially degrading sound?
What troubles me is knowing that the pro electronic crossover is designed to work with stronger signal levels than the home audio gear. The crossover is expecting a stronger input signal than the home audio preamp can deliver. And the pro crossover is outputting a stronger signal than the home audio amp is designed to handle.
Below are comments relevant to my question, quoted from "Sound Reinforcement Handbook" 2nd Ed, 1989 by Gary Davis and Ralph Jones
"...line level phono jack inputs and outputs are intended for use with high impedance equipment, which is basically sensitive to voltage rather than power, so their nominal levels may be specified as -10dBV"
"Typical line level XLR connector inputs and outputs are intended for use with low or high impedance equipment. Since older low impedance equipment was sensitive to power, nominal levels were often specified as +4dBm or +8dBm, levels characteristic of sound reinforcement and recording..."
"A low impedance line output generally may be connected to higher impedance inputs without much change in level. Be aware that if a high impedance output is connected to a low impedance input, that output may be somewhat overloaded which can increase distortion and lower the signal level, and the frequency response may be adversely affected. In some cases, the equipment could be damaged....."
<end quote of Sound Reinforcement Handbook>
Would not connecting the pre-out of an integrated amp to the input of a pro electronic crossover be what is described in the last two sentences from the book, quoted in bold above?
Is using a pro electronic crossover with home audio amps and preamps, even though a common practice, less than ideal and potentially degrading sound?
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In modern gear, there can be RCA line outputs (particularly in the age of modern opamps, which can drive very low Z, with low THD, into high levels, for little outlay) that will drive 600R without issue. There are some which will drive 300R without fuss.
The moral of the story is to know what output stage you're dealing with on an individual basis.
The moral of the story is to know what output stage you're dealing with on an individual basis.
You have described a situation where there should be no issues with a home audio pre driving a pro audio crossover.
I am trying to understand in what situations there might be issues.
A lot of guys will slap a pro electronic crossover into a system with no second thoughts about what is being connected to on either input or output side. A lot of home audio integrated amps from the 70's and 80's had pre-out jacks. No modern opamps in those.
I am trying to understand in what situations there might be issues.
A lot of guys will slap a pro electronic crossover into a system with no second thoughts about what is being connected to on either input or output side. A lot of home audio integrated amps from the 70's and 80's had pre-out jacks. No modern opamps in those.
> pro electronic crossover is designed to work with stronger signal levels than the home audio gear.
It "can". But in a typical 'pro' concert the gear works more than 12dB down from rated level most of the night.
There's crappy "pro" gear, yes. But mostly the stuff is fine. Often more forgiving than "high end hi-fi" gear.
Their distinction between voltage and power, and vague threats of distortion, were dubious in 1989 and moot today.
It "can". But in a typical 'pro' concert the gear works more than 12dB down from rated level most of the night.
There's crappy "pro" gear, yes. But mostly the stuff is fine. Often more forgiving than "high end hi-fi" gear.
Their distinction between voltage and power, and vague threats of distortion, were dubious in 1989 and moot today.
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