Connecting subwoofers to a 2-channel audio amp.
 

Keith G wrote:
"Serge Auckland" wrote in message
...
Eeyore wrote:
Don Pearce wrote:

I would add that finding an ideal position for one sub is hard, and
right positions for two are near enough impossible. Provided there is
very little distortion and the crossover frequency is sensible, there
is no benefit to having a pair of subs - you can't locate the sound
anyway.
Oh yes you can !

That's just an old wives' tale.

Graham

I'm not so sure. I did some tests a couple of months ago after reading
that in the early days of stereo, Philips reckoned that anything below 200
Hz was non-directional, and consequently, a sub and two satellites was
perfectly acceptable for stereo. EMI insisted on two full-range
loudspeakers.

Using sine waves into left only, right only or equally into both, below
220 Hz it was increasingly difficult to decide which was playing, and
impossible below 150 Hz. That of course is in my room, and other rooms may
be different.

However, when using a single subwoofer located to the right of the
right-hand 'speaker and with a crossover of 70Hz, it was disturbing to
hear the extreme bass separate from the 'speakers, possibly as a result of
hearing harmonics from the sub. The disturbing effect went away when the
sub was positioned between the main 'speakers.

I currently use two subs to fill in the bottom half-octave below my main
'speakers, and I have them located as close as possible to the mains to
create effectively a pair of larger 'speakers. Works for me.



This is interesting. This very thread has prompted me to set the 'sub ball'
rolling (finally) and I've scrounged a sub to play with for a few days:

http://www.apah69.dsl.pipex.com/show/subbie2.JPG

http://www.apah69.dsl.pipex.com/show/subbie3.JPG


...with a view to building one (or one like it) and am considering these
atm:

http://www.bkelec.com/HiFi/Sub_Woofers.htm

http://www.iplacoustics.co.uk/SW5%20...0subwoofer.htm


..unless anyone knows better?

But my point is that there is no way of locating the single sub by ear in my
small room and, as the sub in the photos (BK Electronics) has a *variable*
phase adjustment between 0 and 180 deg, is there not a danger of phase
cancellation with two subs, given that they seem to need a lot of adjustment
and faffing with to suit the various different types of music....??

IOW, is a pair of subs a possible complication that might be best *not*
bothered with....??




Should work wonderfully well using one of your 4W SETs............

Seriously, in your room, a single sub should be more than ample. As to
phasing, I really don't understand the point of a variable phase
control. 0 & 180 switched should be provided to phase up the sub with
the mains (which hopefully will be in phase with each other), but apart
from that, I can't see it's possible to match the phase of the main LF,
as it will be frequency dependant. As you suggest, with two subs, trying
to get the phase right would be a nightmare.

Other controls needed are a crossover frequency selector and a level
control. Ideally, if the main speakers are small (say don't go below
70Hz) then the extreme bass should be rolled-off to the mains
considerably improving their power handling and lowering distortion.



S.

Connecting subwoofers to a 2-channel audio amp.
 

Roy wrote:

Phil Allison wrote:

"Kalman Rubinson = Brainless Pile of Kike **** "


Not exactly. What your friend needs is 1 or 2 subs with a
speaker-level crossover. Then, he can connect the main amp outputs to
the sub(s) and then connect the main L/R speakers to the crossover
outputs on the subs. Thus, the crossovers will divide the frequency
spectrum appropriately.



** No such passive sub x-over * really * exists - you PITA
****wit.


Well that's EXACTLY how my Harbeth subs work.

Now who's brainless, gob****e?

Which model of Harbeth subwoofer do you have?

--
Eiron.

Connecting subwoofers to a 2-channel audio amp.
 

Guys,

I am not sure if Whatmough sub's are available in UK.

I strongly suggest having a look at them. Its not the patriotic Aussie
in me blantantly favoring it, but they are really good. I have used
their entire range of speakers for almost 6 years now. Here is the
configuration for the Tornado range I own -

Configuration 1x300mm (12") cellulose fibre cone with a very long throw
suspension. This driver has a rubber surround and high temperature
voice coil.
Enclosure 25mm thick cabinet walls, fully braced bass enclosure with
bass reflex loading.
Amplifier 240 Watts continuous power output. Line and speaker level
outputs and inputs. Auto on/off switch. Thermal output protection.
Continuously variable gain (volume) control.
Electronic low-pass crossover from 40 to 160Hz.
Bass Extension 22Hz -3dB, usable bass to well below 20Hz
Average levels of 50 Watts.
Dimensions 500H x 470W x 570D mm.
Weight 30kg
Finish Bubinga real wood veneer

More information on their entire range is available on -

http://whatmough-whise.com/subwoofers.htm

I had the pleasure to meet up with the chief designer of the Impulse
range and understand the philosophy behind the design. Bloody awesome.
Cheers

Max

Keith G wrote:
"Serge Auckland" wrote in message
...
Eeyore wrote:

Don Pearce wrote:

I would add that finding an ideal position for one sub is hard, and
right positions for two are near enough impossible. Provided there is
very little distortion and the crossover frequency is sensible, there
is no benefit to having a pair of subs - you can't locate the sound
anyway.

Oh yes you can !

That's just an old wives' tale.

Graham


I'm not so sure. I did some tests a couple of months ago after reading
that in the early days of stereo, Philips reckoned that anything below 200
Hz was non-directional, and consequently, a sub and two satellites was
perfectly acceptable for stereo. EMI insisted on two full-range
loudspeakers.

Using sine waves into left only, right only or equally into both, below
220 Hz it was increasingly difficult to decide which was playing, and
impossible below 150 Hz. That of course is in my room, and other rooms may
be different.

However, when using a single subwoofer located to the right of the
right-hand 'speaker and with a crossover of 70Hz, it was disturbing to
hear the extreme bass separate from the 'speakers, possibly as a result of
hearing harmonics from the sub. The disturbing effect went away when the
sub was positioned between the main 'speakers.

I currently use two subs to fill in the bottom half-octave below my main
'speakers, and I have them located as close as possible to the mains to
create effectively a pair of larger 'speakers. Works for me.



This is interesting. This very thread has prompted me to set the 'sub ball'
rolling (finally) and I've scrounged a sub to play with for a few days:

http://www.apah69.dsl.pipex.com/show/subbie2.JPG

http://www.apah69.dsl.pipex.com/show/subbie3.JPG


...with a view to building one (or one like it) and am considering these
atm:

http://www.bkelec.com/HiFi/Sub_Woofers.htm

http://www.iplacoustics.co.uk/SW5%20...0subwoofer.htm


..unless anyone knows better?

But my point is that there is no way of locating the single sub by ear in my
small room and, as the sub in the photos (BK Electronics) has a *variable*
phase adjustment between 0 and 180 deg, is there not a danger of phase
cancellation with two subs, given that they seem to need a lot of adjustment
and faffing with to suit the various different types of music....??

IOW, is a pair of subs a possible complication that might be best *not*
bothered with....??

Connecting subwoofers to a 2-channel audio amp.
 

correction ... i own the Typhoon range more information is available on
-

http://www.pymblehifi.com.au/Whatmough%20Subwoofers.htm


max graff wrote:
Guys,

I am not sure if Whatmough sub's are available in UK.

I strongly suggest having a look at them. Its not the patriotic Aussie
in me blantantly favoring it, but they are really good. I have used
their entire range of speakers for almost 6 years now. Here is the
configuration for the Tornado range I own -

Configuration 1x300mm (12") cellulose fibre cone with a very long throw
suspension. This driver has a rubber surround and high temperature
voice coil.
Enclosure 25mm thick cabinet walls, fully braced bass enclosure with
bass reflex loading.
Amplifier 240 Watts continuous power output. Line and speaker level
outputs and inputs. Auto on/off switch. Thermal output protection.
Continuously variable gain (volume) control.
Electronic low-pass crossover from 40 to 160Hz.
Bass Extension 22Hz -3dB, usable bass to well below 20Hz
Average levels of 50 Watts.
Dimensions 500H x 470W x 570D mm.
Weight 30kg
Finish Bubinga real wood veneer

More information on their entire range is available on -

http://whatmough-whise.com/subwoofers.htm

I had the pleasure to meet up with the chief designer of the Impulse
range and understand the philosophy behind the design. Bloody awesome.
Cheers

Max

Keith G wrote:
"Serge Auckland" wrote in message
...
Eeyore wrote:

Don Pearce wrote:

I would add that finding an ideal position for one sub is hard, and
right positions for two are near enough impossible. Provided there is
very little distortion and the crossover frequency is sensible, there
is no benefit to having a pair of subs - you can't locate the sound
anyway.

Oh yes you can !

That's just an old wives' tale.

Graham


I'm not so sure. I did some tests a couple of months ago after reading
that in the early days of stereo, Philips reckoned that anything below 200
Hz was non-directional, and consequently, a sub and two satellites was
perfectly acceptable for stereo. EMI insisted on two full-range
loudspeakers.

Using sine waves into left only, right only or equally into both, below
220 Hz it was increasingly difficult to decide which was playing, and
impossible below 150 Hz. That of course is in my room, and other rooms may
be different.

However, when using a single subwoofer located to the right of the
right-hand 'speaker and with a crossover of 70Hz, it was disturbing to
hear the extreme bass separate from the 'speakers, possibly as a result of
hearing harmonics from the sub. The disturbing effect went away when the
sub was positioned between the main 'speakers.

I currently use two subs to fill in the bottom half-octave below my main
'speakers, and I have them located as close as possible to the mains to
create effectively a pair of larger 'speakers. Works for me.



This is interesting. This very thread has prompted me to set the 'sub ball'
rolling (finally) and I've scrounged a sub to play with for a few days:

http://www.apah69.dsl.pipex.com/show/subbie2.JPG

http://www.apah69.dsl.pipex.com/show/subbie3.JPG


...with a view to building one (or one like it) and am considering these
atm:

http://www.bkelec.com/HiFi/Sub_Woofers.htm

http://www.iplacoustics.co.uk/SW5%20...0subwoofer.htm


..unless anyone knows better?

But my point is that there is no way of locating the single sub by ear in my
small room and, as the sub in the photos (BK Electronics) has a *variable*
phase adjustment between 0 and 180 deg, is there not a danger of phase
cancellation with two subs, given that they seem to need a lot of adjustment
and faffing with to suit the various different types of music....??

IOW, is a pair of subs a possible complication that might be best *not*
bothered with....??

Connecting subwoofers to a 2-channel audio amp.
 

Posts like this do not deserve any response but, in the small
possibility that someone takes him seriously, I will add that there
are several powered subwoofers which
(1)take speaker-level inputs,
(2)have a passive speaker-level crossover,
(3)feed the high-pass output to terminals for the left/right speakers
and,
(4)via a resistive network, pass the LP output to the built-in power
amp and subwoofer driver.

Kal

On Sat, 13 Jan 2007 01:15:54 +1100, "Phil Allison"
wrote:


"Kalman Rubinson = Brainless Pile of Kike **** "


Not exactly. What your friend needs is 1 or 2 subs with a
speaker-level crossover. Then, he can connect the main amp outputs to
the sub(s) and then connect the main L/R speakers to the crossover
outputs on the subs. Thus, the crossovers will divide the frequency
spectrum appropriately.


** No such passive sub x-over * really * exists - you PITA ****wit.

Any specs or web pages that suggest otherwise a total FICTION !!



For this, I prefer powered (built-in amp) subs so that they do not
draw any significant power from the main amp


** Which UTTERLY contradicts your previous para.


APPARENTLY: There is absolutely no upper limit to the * asinine *****
that know nothing poseurs like this cretin will attempt promulgate.

But I am more than happy to stick a giant spanner in the dumb ****'s works.





........ Phil

Connecting subwoofers to a 2-channel audio amp.
 

Kalman Rubinson wrote:

Posts like this do not deserve any response but, in the small
possibility that someone takes him seriously, I will add that there
are several powered subwoofers which
(1)take speaker-level inputs,
(2)have a passive speaker-level crossover,
(3)feed the high-pass output to terminals for the left/right speakers
and,
(4)via a resistive network, pass the LP output to the built-in power
amp and subwoofer driver.

I think you will find that they
1) take speaker-level inputs
2) which are directly connected to terminals for the left/right speakers
3) via a resistive network, combine L+R and feed it to an electronic
LP filter and thence to the built-in power amp and subwoofer driver.

Please feel free to give an example of one that works your way.

--
Eiron.

Connecting subwoofers to a 2-channel audio amp.
 

"Serge Auckland" wrote in message
...
Keith G wrote:


IOW, is a pair of subs a possible complication that might be best *not*
bothered with....??




Should work wonderfully well using one of your 4W SETs............



Well, on my *8W* SET/InFidelios the results are astounding - 'listening' by
leaning my head back against the (drywall partition) wall, the bass from
Bjork's 'Headphones' without the sub rattles my head anyway. With the sub
though, it is not really bearable for long and quite queasy but there is
some 'wuffa wuffa wuffa' roll-off after a seriously deep bit!

Interestingly, the bass with the sub doesn't actually really sound any
deeper than the speakers on their own, only *feels* it...!!

More, much more, to do yet - mebbe even some recording comparisons....



Seriously, in your room, a single sub should be more than ample.


Sure, I don't think I could stand more than the one!!


As to
phasing, I really don't understand the point of a variable phase control.
0 & 180 switched should be provided to phase up the sub with the mains
(which hopefully will be in phase with each other), but apart from that, I
can't see it's possible to match the phase of the main LF, as it will be
frequency dependant. As you suggest, with two subs, trying to get the
phase right would be a nightmare.


I've twiddled it back and forth and can't say it makes a lot of difference
anyway and it ends up back at 0 deg!



Other controls needed are a crossover frequency selector and a level
control. Ideally, if the main speakers are small (say don't go below 70Hz)
then the extreme bass should be rolled-off to the mains considerably
improving their power handling and lowering distortion.


Not sure I understood that....??

Connecting subwoofers to a 2-channel audio amp.
 

"Keith G" wrote


Well, on my *8W* SET/InFidelios the results are astounding - 'listening'
by leaning my head back against the (drywall partition) wall, the bass
from Bjork's 'Headphones' without the sub rattles my head anyway. With the
sub though, it is not really bearable for long and quite queasy but there
is some 'wuffa wuffa wuffa' roll-off after a seriously deep bit!

Interestingly, the bass with the sub doesn't actually really sound any
deeper than the speakers on their own, only *feels* it...!!

More, much more, to do yet - mebbe even some recording comparisons....


Footnote:

Swim has been subjected to brief snatches of extreme bass on a with/without
sub basis throughout the evening. I have just asked her for a snap answer to
the 'Do I need a sub?' question!

Immediate answer - 'Nope'.....

??

?

Connecting subwoofers to a 2-channel audio amp.
 

"Roy"

Well that's EXACTLY how my Harbeth subs work.


** You have totally failed to take account of the context - ****wit.





........ Phil

Connecting subwoofers to a 2-channel audio amp.
 

"Kalman Rubinson ****ing MORON "



Posts like this do not deserve any response but, in the small
possibility that someone takes him seriously,


** I am ABSOLUTELY RIGHT !!

YOU are know nothing, brain dead audiophool arsehole.



I will add that there
are several powered subwoofers which
(1)take speaker-level inputs,
(2)have a passive speaker-level crossover,


** No they do not.

Ever pulled one apart to see what is ACTUALLY fitted inside??

Their maker's lie.




......... Phil