From: lauusitalo@tnclus.tele.nokia.fi
Subject: Re: Another Sub Woofer question
Organization: Nokia Telecommunications.
Date: Mon, 4 Jan 1993 06:43:18 GMT

In article <1992Dec31.170723.12609@colorado.edu>, baldwin@frodo.colorado.edu (Dan "Viper" Baldwin) writes:
> 
> 	I have a Yamaha RXV-850 reciever and an Infinity 10" subwoofer
> powered with 100 Watts. From answers to a previous post, I have gathered
> that to reap the maximum benifits from the sub-woofer, I need to include
> a cross over so that signals going to the main speakers are devoid of
> lower frequencies ( say < 200 HZ ). Does the cross over connect to the high
> level main speaker terminals of the reciever and then divide the signal
> to the mains and the subwoofer ?  How much is a good crossover ? Where
> does one get one ?  If there is a choice of roll over frequencies, where
> is a good cut off ? My main speakers are Klipsh Forte I .
>   
> Thanks for any responses,
> Dan Baldwin  baldwin@frodo.colorado.edu 

        Basic things connecting subwoofer to setups:
        1. Use active filter if possible. If you have separate amps for
           main speakers and subwoofer then you have to use active filter.
        2. Use low crossover frequency ( <200Hz, preferably <100Hz or <50Hz )
        
        In your situation you could and should use active filter. If your
        Yamaha has pre-out (from preamp) and pre-in (to poweramp) connectors
        then you connect active filter between them. To this filter's
        subwoofer connector you connect your sub amp. And to pre-in connector
        only main speaker lines.

        You could also use one of your line outs to connect your sub filter,
        but then you have to adjust both amplifiers volume knobs. And you
        could not filter low frequencies from your main speakers. 
        Also main speaker high level lines could be used. But then your filter
        should include resistors to scale this high level output to about line 
        level. Otherwise your filter would propably melt. And again you could 
        not filter your main speakers.

        If RXV-850 has subwoofer output then you could use that to connect
        to sub amp. Crossover frequency is propably quite high, however.
        
        To be able to filter main speakers is not always necessary because
        some speakers "miss" low frequencies allready.

        I have no knowledge about your main speakers but I have had a feeling
        that Klipsh's are quite nonsensitive, so if you abandon your other
        amplifier and go for passive filters then you would need more power
        in one amplifier than with active system.
        
        So buy an active filter with adjustable crossover frequency and bass
        level and you will be happy. I hope. I guess there is many stores
        selling these and they will be more than happy to serve you.
        (I have no idea about American sale people, but I can imagine one.)

        Lauri

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Lauri Uusitalo                  I          "Life is hard,          
lauri.uusitalo@ntc.nokia.com    I                then you die..."  
lauusitalo@tnclus.tele.nokia.fi I