Hi all,

Small room, nearly 12' square w/11' cathedral ceiling. 5.1 system
w/150W powered sub currently placed in the right rear corner, firing
down onto a wood floor.

I am bothered by the directionality of the sub (it's right behind me)
and am wondering if buying an identical unit and placing it in the
left rear corner would improve things enough to justify the cost.

What say you?

Also, can I just use a Y-splitter coming off the AVR to feed both
subs, or do I have to put them in a series?

Thanks!

Tim


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"Tim Breen" wrote in message
...
Hi all,

Small room, nearly 12' square w/11' cathedral ceiling. 5.1 system
w/150W powered sub currently placed in the right rear corner, firing
down onto a wood floor.

I am bothered by the directionality of the sub (it's right behind me)
and am wondering if buying an identical unit and placing it in the
left rear corner would improve things enough to justify the cost.

What say you?

Also, can I just use a Y-splitter coming off the AVR to feed both
subs, or do I have to put them in a series?

Thanks!

Localization of a subwoofer can be caused by the following phenomena:

1. The subwoofer is crossed over at a high frequency. Above 60 Hz, the ear
can frequently localize a sub.
2. Articles in the room, furniture, walls, etc., resonate with the sub,
generating sounds at higher frequencies that are easily localizable.
3. The crossover leaks higher frequencies to the sub, or the sub has
significant harmonic distortion.

The term "subwoofer" has been corrupted by use from the original meaning.
Originally, a subwoofer was specifically a low frequency driver intended to
compliment full range speakers. Some of these subs are crossed over at very
low frequencies. For example, my sub is crossed over at 35 Hz, to compliment
Kef Reference III full range speakers. At very low crossover frequencies,
subwoofer sound cannot be localized, except by telltales provided by
vibrating panels and room furnishings.

However, with the advent of the "satellite-sub" system, the so-called
subwoofer became just another bass driver. These drivers are crossed over at
much higher frequencies, sometimes as high as 120 Hz. When this is done,
the physics of sound makes localization inevitable.

If your subwoofer is crossed over at a high frequency, it is possible that
you will find more satisfaction with an additional, symmetrically placed
sub. However, since such subs actually support the midrange, placement close
to the satellites is more apt to provide the coherence you feel is missing.

"Tim Breen" wrote in message
...
Hi all,

Small room, nearly 12' square w/11' cathedral ceiling. 5.1 system
w/150W powered sub currently placed in the right rear corner, firing
down onto a wood floor.

I am bothered by the directionality of the sub (it's right behind me)
and am wondering if buying an identical unit and placing it in the
left rear corner would improve things enough to justify the cost.

What say you?

I think you can minimize directionality by lowering the crossover point on
the feed to the sub. That is if your mains can provide some bass output.

Also, can I just use a Y-splitter coming off the AVR to feed both
subs, or do I have to put them in a series?

splitter

ScottW

"Robert Morein" wrote in message
...

"Tim Breen" wrote in message
...
Hi all,

Small room, nearly 12' square w/11' cathedral ceiling. 5.1 system
w/150W powered sub currently placed in the right rear corner, firing
down onto a wood floor.

I am bothered by the directionality of the sub (it's right behind me)
and am wondering if buying an identical unit and placing it in the
left rear corner would improve things enough to justify the cost.

What say you?

Also, can I just use a Y-splitter coming off the AVR to feed both
subs, or do I have to put them in a series?

Thanks!

Localization of a subwoofer can be caused by the following phenomena:

1. The subwoofer is crossed over at a high frequency. Above 60 Hz, the ear
can frequently localize a sub.

Funny everybody else says 80 Hz.

2. Articles in the room, furniture, walls, etc., resonate with the sub,
generating sounds at higher frequencies that are easily localizable.
3. The crossover leaks higher frequencies to the sub, or the sub has
significant harmonic distortion.

The term "subwoofer" has been corrupted by use from the original meaning.
Originally, a subwoofer was specifically a low frequency driver intended
to
compliment full range speakers. Some of these subs are crossed over at
very
low frequencies. For example, my sub is crossed over at 35 Hz, to
compliment
Kef Reference III full range speakers. At very low crossover frequencies,
subwoofer sound cannot be localized, except by telltales provided by
vibrating panels and room furnishings.

However, with the advent of the "satellite-sub" system, the so-called
subwoofer became just another bass driver. These drivers are crossed over
at
much higher frequencies, sometimes as high as 120 Hz. When this is done,
the physics of sound makes localization inevitable.

If your subwoofer is crossed over at a high frequency, it is possible that
you will find more satisfaction with an additional, symmetrically placed
sub. However, since such subs actually support the midrange, placement
close
to the satellites is more apt to provide the coherence you feel is
missing.

"Tim Breen" wrote in message
...
Hi all,

Small room, nearly 12' square w/11' cathedral ceiling. 5.1 system
w/150W powered sub currently placed in the right rear corner, firing
down onto a wood floor.

I am bothered by the directionality of the sub (it's right behind me)

If you can localize it it's probably crossed over at to high a frequency, or
maybe it's just turned up to loud relative to the mains.

and am wondering if buying an identical unit and placing it in the
left rear corner would improve things enough to justify the cost.

What say you?

The corner is usually the best place to put a subwoofer.

Are teh speakers a matched set or is the sub an add on bought after the
other speakers? It may be that the location you have the sub in is exciting
a specific frequency, very often 100 Hz bumps in response occur because of
room dimensions.

If it were me I would first experiment with the above refernced points and
see what happens.

Get a Radio Shack SPL meter, the analog one and use it to balance the spl of
all the speakers so they match.

If you get the localization problem solved and you still want an additional
sub go for it, just make sure it's crossed over at the same frequency.
Multiple drivers covering the same frequency range means less work for each
driver.
You will run each sub at a lower spl because they add together.


Also, can I just use a Y-splitter coming off the AVR to feed both
subs, or do I have to put them in a series?

Splitter should be fine, assuming they are powered subs.

Thanks!

Tim


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"Michael McKelvy" wrote in message
ink.net...

"Robert Morein" wrote in message
...

"Tim Breen" wrote in message
...
Hi all,

Small room, nearly 12' square w/11' cathedral ceiling. 5.1 system
w/150W powered sub currently placed in the right rear corner, firing
down onto a wood floor.

I am bothered by the directionality of the sub (it's right behind me)
and am wondering if buying an identical unit and placing it in the
left rear corner would improve things enough to justify the cost.

What say you?

Also, can I just use a Y-splitter coming off the AVR to feed both
subs, or do I have to put them in a series?

Thanks!

Localization of a subwoofer can be caused by the following phenomena:

1. The subwoofer is crossed over at a high frequency. Above 60 Hz, the
ear
can frequently localize a sub.

Funny everybody else says 80 Hz.

Split the difference?

Thanks for your input, guys. Following your suggestions I now own a RS
SPL and have chased USENET threads on "Newbie for Subwoofers" and have
put some light on a murkey subject for me.

One follow-up question: the documentation for my satellites (JBL)
states that the optimum crossover is 120Hz but barring an exact match
to set the ARV's crossover at the nearest _lower_ setting, i.e.,
100Hz. I now know (thanks again) that going the opposite direction, up
to 150Hz, would result in localization. My question is what happens to
the sound between 100 and 120? Do I "lose" that bass, or is there
generally enough slack (stretch?) for the sub and the satellites to
carry the load without either moving into distortion?

Tim


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"Tim Breen" wrote in message
...
Thanks for your input, guys. Following your suggestions I now own a RS
SPL and have chased USENET threads on "Newbie for Subwoofers" and have
put some light on a murkey subject for me.

One follow-up question: the documentation for my satellites (JBL)
states that the optimum crossover is 120Hz but barring an exact match
to set the ARV's crossover at the nearest _lower_ setting, i.e.,
100Hz. I now know (thanks again) that going the opposite direction, up
to 150Hz, would result in localization. My question is what happens to
the sound between 100 and 120? Do I "lose" that bass, or is there
generally enough slack (stretch?) for the sub and the satellites to
carry the load without either moving into distortion?

Tim


If you crossover at a higher than optimum point you will get a "bump" in the
frequency response, IOW those frequencies in the bumb will be higher,
possibly causing an unpleasant boost. All of this is of course contingent
to how your room interacts with your speakers. You may have a dip where yor
bump might be and it would then be filled in. In short it's a bit of a
crapshoot until you experiment with placement and crossover points.