Conference hips::uk_audioo

Hi Tim,

There are two types of sub-woofer.  One is called Passive, the other is 
Active.

The Passive type is connected into the speaker leads going to the normal 
stereo pair, and it probably includes a high-pass filter which is fitted 
between your stereo pair and the amp to stop them trying to reproduce the 
frequencies the sub-woofer works on.

This type has the potential to work very well, since it is run by your own 
amp and will have it's character, if done well I don't see why the passive 
crossover should degrade the sound TOO much.  The downside is that your amp 
has to provide the guts to drive the thing, straining a little more when 
driving the stereo pair.  

The more expensive Active type runs off a line-level signal and contains an 
amplifier itself.  The amp CAN be specially designed for the application it 
is dedicated to, the frequencies amplified for the sub can be actively 
filtered in the box too.  I have learnt that the more expensive the active 
sub-woofer, the more taught and less boomy the bass at a given volume 
level.

The second type has best potential for integrating with existing speakers 
since most provide controls on the internal amp, and should mean you can 
relieve your existing stereo amp of having to drive the real low bass 
significantly (i.e. that under around 70Hz).

I'm not familiar with your Sony's.  The sub type to choose depends on 
budget and if you have some particular Bookshelf speakers in mind.

I think manufacturers Passive sub-woofer systems are often matched with too 
small sattelites.  If they then have to design the system to have the 
sub-woofer work on frequencies over 100Hz then will become an obvious mono 
boom-box, ruining your stereo image.

On the other hand good Passive systems have the potential to be designed as 
a complete system, including all crossovers to match it with the dedicated 
satellite speakers.

There is a group test of 3 systems (including a/v centre and surround 
speakers) in Home Cinema Winter 1994.  
	The Goodmans GLL Areana package for	�395
	The Pioneer S-W33 + C-V201		�250
	Tannoy 623 (times 5) + 625ALF (5x189 + �595) (Active sub not as 
							good as REL)

I have only heard bookshelf sub-satellites at hi-fi shows in large demo 
halls so I can't give much in actual performance.

Rob.

    And there's the Bose Acoustimass if your wallet can stand it...

>    And there's the Bose Acoustimass if your wallet can stand it...

And your stomach^H^H^H^H^H^H^H^H ears ...

                                                        
                                                  - Rik -

	The sound of a system is likely to be 'lost' in a large room 
	without the extra bass, but in a small room the bass becomes
	overpowering.

	Tricky choice.

	-John

    
    I'm using a REL Storm in a LINN Activ Kaber system and the subwoofer
    blends in virtually seelessly (using a test disc there is a slight
    overlap at 40Hz). It took a while to set up, but is definitely wotrh
    it, compared to my original Yamaha SW50. On both music and AV, the bass
    is solid, tight and where the signal requires, deep.
    
    There was a recent review staing that it was not worth the extra 200
    quid over a Strata - utter tosh. Whilst the Strat is good for AV, it
    isn't quite subtle enough for HIFI.
    
    One word of warning; if you are in a terrace and like dance music, keep
    well clear.
    

    I wouldn't have thought Activ Kabers would need a subwoofer. Whenever
    I've heard them they've had more than enough bass for me. Also I
    thought that they went down to about 25Hz, not the 40Hz crossover point
    you talk of. The passive bi-amped Kabers I've go are very light on bass
    (nothing below 40Hz) so I could see a subwoofer being of use here.
    
    Still I wouldn't mind listening to them.
    
    Has anyone heard Linn's new Lk500 (This name could be wrong) for use in
    Home Cinema it's placed between Kabers and Keltiks.
    
    Rik - who misses his Isobariks and would like another LK100 so he could
    go Activ with his Kabers.
    
    Thinking about it I'd expect that active speakers make the best
    parteners for subwoofers as you can tune the crossover points etc.

    Rik,
    
    The activ Kabers are touted to go flat to 40Hz, are still audible
    at 31.5Hz, but not at 25Hz (the tones on the test disc). 
    
    One thing I've found, both on my system and a friends (3 Klouts and
    Kabers) is that the bass does extend to the low registers, but the
    subwoofer adds the that last bit. At those frequenices, instruments
    like bass guitars and drums, tend to lose a little volume;
    the subwoofer, when set up correctly, boosts the volume to be in line with 
    the original intent.
    
    An unusual artifact of the subwoofer is that the soundstage (or in my
    words, the depth) seems to increase. LINN never seem to have had a
    problem with this, but the subwoofer gives a more 3D feel to the music.
    
    
    Tracks were I have noticed special improvement (of those I've so far
    listened to) include...
    
    Annie Lennoxs' "Diva" and "Medusa" albums have an entire rhythm around 25 -
    30Hz throughout a lot of the tracks that I never heard on the Kabers.
    
    Finitrbes' "Dark" is currently listed as "only when the neighbours are
    out".
    
    Griegs' "Peer Gynt Suite" or Holsts'  "Planets" suddenly gain massive power.
    
    The The and Sinead O'Conner, whilst nothing new is recovered, both
    benefit from the tightening and strengthening of the bass in the lower
    registers.
    
    Beware of passive Kabers. They go flat to 60Hz, dip rapidly before a
    spike at 40Hz. A friend who set up his passive Kabers required a fair
    bit of playing around to get the sound right. Activ Kabers were much
    easier to set up.
    
    Dave.