advanced processor technical advice?

[lbstyling]

hello all
i have a processor power amps setup and would like to know about what too look for in the specs for getting a good match between a new pro and power amp.
ignoring the ability of the pro and power for the moment, im told i need to make sure the pro and power input/outputs arnt 'clipping'.
im told that i need to look for a pro with a high voltage output - is this right?

how do i test for clipping? - i have a multimeter, and various mic setups for testing speakers.

also a big difference between input impedence and output imp aswell?

any advice is appreciated

thanks people. :T

[Kal Rubinson]

I have not heard of matching problems between processor and amps, in general. Perhaps you can tell us which specific items you have.

BTW, the output impedance of the processor should be much lower than the input impedance of the amps to insure optimum voltage transfer.

[lbstyling]

oh my... im in the presence of royalty here!- hello Kal!

i have just sold my processor, but im asking so i can select a new processor.

having talked to a newly qualified 'CEDIA Home Cinema Design Specialist' i was told that i need to insure that the processor and power amps work together well, specifically i need to know if the output of the processor doesnt clip driving the power amp input when playing back near or at reference level.
i would just like to know how to test for this realy.

the chap also says that all amps sound the same when all factors are matched and certain perameters are met in a ABX test (ie no clipping,good snr etc)- i dont particularly agree with him, but was interested to know if this clipping between pro and power realy happens, and if i can do anything to stop/prevent it.

[Kal Rubinson]

Some processors have higher output than others and some power amps have higher input sensitivities (input voltage for rated output) than others. I would want a processor which is capable of putting out twice the rated input sensitivity of the power amp. In practice, I have never found this to be an issue but I am not a head banger nor do I play "Das Boot" at reference levels (or louder).

[lbstyling]

thankyou karl, i appreciated :T

i would like to know if anyone knows to test for this (out of curiosity) :T

[aarsoe]

I think it will be difficult these days to find a processor that beside the overall volume control also will have level settings for each input - allowing you to get a near perfect match.
Kal - all though I tend to agree I do remember a Krell preamp of mine that had such a high amplification that the only usable range was from 0 db to 9'clock on the volume knob. That is also not recommendable..

[Kal Rubinson]

I think it will be difficult these days to find a processor that beside the overall volume control also will have level settings for each input - allowing you to get a near perfect match.

Some do, some don't.

Kal - all though I tend to agree I do remember a Krell preamp of mine that had such a high amplification that the only usable range was from 0 db to 9'clock on the volume knob. That is also not recommendable..

Agreed but the OP was concerned about clipping the preamp output and, obviously, that would not be an issue with that Krell and whatever it was feeding.

[aarsoe]

Correct - but it could clip the power amp if I wasn't carefull..

[whoaru99]

Correct - but it could clip the power amp if I wasn't carefull..

Most pro audio amps have adjustable gain controls and often two or three different input sensitivity selections. This combination facilitates proper setup of the system's overall gain structure across a wide mix of different gear.

Also, for example, the inputs on the QSC PLX amps I use for HT will accept up to 10Vrms before overloading, yet the amps require only ~1.5V input signal for full output power.

[whoaru99]

im told that i need to look for a pro with a high voltage output - is this right?

Maybe.

What you need to look at first, IMO, is the amp input sensitivity. Many "home audio" amps have input sensitivity in the 1.2-1.5V range. Many pro audio amps have a similar input sensitivity range. Point being, there usually isn't a problem in this regard.

Where I've seen people struggle is when they have mixed a lot of different gear with widely different input sensitivity and or gain. If these various devices don't have adjustment or enough adjustment to make up the differences, then there is some potential for gain structure problems. Not fully understanding what the real issue was/is they typically (and falsely, IMO) blame it on an output/input level mismatch between consumer and pro audio gear.

Going even further, one must make some consideration even down to the speaker sensitivity. Another example, if you have Klipsch speakers that tend to have high sensitivity (say 96dB) and mix those with a DIY sub having low sensitivity (say 86dB), that 10dB difference has to be considered in your overall gain structure too.