Re: Graphic EQ Shootout in San Francisco

Name    : 
E-Mail  : 
Subject : 

Comments:
: : Lew,

: : <i>.... and neither, one would think, should they need "built in noise reduction". Or have I missed something there?</i>

: : In defense of this "feature:" perhaps the intent is to reduce noise from earlier in the signal chain?

: : -a

: ====================
: AFAIK the companding NR is wrapped around the internal EQ. I find it highly unlikely their marketers would overlook the opportunity to add yet another feature (SENR or downward expansion) if it did it.

: In general companding NR offers to reduce the noise floor of a signal channel with limited dynamic range by first compressing (typically at 2:1) the input then expanding the output (at 1:2), during periods with no signal present, it will expand down the channel noise floor by the amount of compressor/expander gain. In addition, depending upon where you set the unity gain inflection point you can also reduce the maximum signal level by the same ratio to better match input dynamic range to the channel's. From what I could gather from reading a spec sheet when these were new, and from hearing anecdotal reports it appears they may have biased the inflection point more toward generating a lower published noise floor spec when no signal was present than handling a higher max level when signal was. FWIW if operating above the compador's inflection point it is actually increasing the noise floor.

: For the record my speculations are just that as I have never bench tested a unit. THD+N testing would be instructive as any steady signal at or near the inflection point would reveal the true channel noise floor, plus any noise added by the NR processing. 

: This product has been effectively marketed and it has sold well. I would expect more consumers to be able to confirm that it doesn't add to their system's noise floor when no signal is present than to hear and blame it for any channel noise in the presence of signal or blame it for overload issues. 

: It is hard to argue with commercial success.... as a corollary to "Roberts rule of Right", if that many customers think it's right, it must be right, at least for them.  

: JR

: PS: Companding and a healthy amount of high frequency pre/de-emphasis made cassete decks with nominal 55dB dynamic range actually listenable.



Optional Link URL:  
Link Title:         
Optional Image URL: