speaker phasing

[[email protected]]

I'm making some additions to my stereo system and I'll try to explain this as concise as possible. I have two additional speakers which I'd like to connect to the receiver in the living room. The room is about 15 X 22 feet. The existing two speakers are situated against an inside wall facing the windows. They are properly phased and sound very good. One of these existing speakers (left side speaker A system), is very slightly caddy corner so thatit projects into the room. I would like to connect the additional left side counterpart on the opposite window wall so that it's speaker, (proposed speaker B system) is doing the same thing from the corner it's in. The new right speaker from proposed system B will essentially facing it's counterpart from speaker A system,separated by about 15 feet. What I'm trying to accomplish is more sound filling the room from more directions and hopefully simulating a sort of pseudo "surround" type of effect. But I'm not sure abouthow this is going to work out. Perhaps this is a mistake, so I thought I'dask.

If all four speakers are facing one another and are in phase, and by this Imean before connecting to the receiver confirming that a small battery makes all four cones move in the same direction, connected like this what happens when the two lefts for instance are outputting the same signal. With the cones facing each other, will the projected sound buck and effectively try to cancel? Or should both cones in proposed B system be in phase as a pair but out of phase with respect to A system? Or should I forget the whole thing and just stick with my two existing A speakers? I hope I've explainedthis well. Thanks for any advice. Lenny

 

[William Sommerwerck]

This is a common source of confusion. "Same direction" means "outward or
inward", /not/ same direction viewed from overhead. The same signal should
produce compression or rarefaction from all speakers.

Other than a sore back from moving your speakers, it costs nothing to
experiment. As dave says, start with them in phase, then play around.

 

[Phil Allison]

"William Sommerwerck"

This is a common source of confusion. "Same direction" means "outward or
inward", /not/ same direction viewed from overhead. The same signal should
produce compression or rarefaction from all speakers.

** Correct.

Phasing similar speakers is all about making the low frequency output from
each *reinforce* the others rather than cancel.

Compared to the wavelengths of low frequency sound, woofers are a point (
hence omnidirectional ) source of sound pressure - so it is irrelevant
which way the cone faces.

Ideally, a listener should be seated at the same distance from each speaker
so all time ( of arrival ) delays are identical and do NOT create phase
changes.


.... Phil

 

[Phil Allison]

"dave the dickhead"

There is no such thing as correct time of arrival type of phase coherence
in modern electronic media.

** WTF is meant by "modern electronic media " ??

Got nothing to do with my comments, what ever this idiot says.

Everything is close-miked and smeared together with "pan pots"

** Pan pots do not "smear" .

and any spatial sensation is created with DSP.

** Laughably stupid and wrong.

In real life, the stereo "sweet spot" has room for one person at a time.

** Correct.

Due to the criteria I just mentioned.

" Ideally, a listener should be seated at the same distance from each
speaker
so all time ( of arrival ) delays are identical and do NOT create phase
changes."



.... Phil

 

[Phil Allison]

"dave"

Do you work with roustabouts or what? Modern electronic media like Pop
Tunes and Rock tracks.

** So any popular music recording made in the last 50 years.

Yes Pan Pots suck, almost as bad as graphic equalizers.

** But do not smear - you fucking nutter.

The sound stage can only be preserved by recording live ..

** Your hobby horse - not mine.



..... Phil

 

[Phil Allison]

"dave dickhead"

I appear to have trod upon sacred ground of some sorts. So sorry.

** Your the one preaching strange religion - fuckwit.

 

[[email protected]]

I'm making some additions to my stereo system and I'll try to explain this as concise as possible. I have two additional speakers which I'd like to connect to the receiver in the living room. The room is about 15 X 22 feet.The existing two speakers are situated against an inside wall facing the windows. They are properly phased and sound very good. One of these existingspeakers (left side speaker A system), is very slightly caddy corner so that it projects into the room. I would like to connect the additional left side counterpart on the opposite window wall so that it's speaker, (proposedspeaker B system) is doing the same thing from the corner it's in. The newright speaker from proposed system B will essentially facing it's counterpart from speaker A system,separated by about 15 feet. What I'm trying to accomplish is more sound filling the room from more directions and hopefully simulating a sort of pseudo "surround" type of effect. But I'm not sure about how this is going to work out. Perhaps this is a mistake, so I thought I'd ask.



If all four speakers are facing one another and are in phase, and by thisI mean before connecting to the receiver confirming that a small battery makes all four cones move in the same direction, connected like this what happens when the two lefts for instance are outputting the same signal. With the cones facing each other, will the projected sound buck and effectively try to cancel? Or should both cones in proposed B system be in phase as a pair but out of phase with respect to A system? Or should I forget the wholething and just stick with my two existing A speakers? I hope I've explained this well. Thanks for any advice. Lenny

Well I tried a few different scenarios and eventually I ended up with all four speakers in phase connected to both A and B front outputs. It would have been really nice if I could have used the rear speaker circuit of the receiver as it was intended, but unfortunately that was not possible.

I never mentioned that the receiver is an old Sansui QRX5500. That was a top of the line 4 channel SQ unit circa 1975. Sadly neither the four channel or the SQ circuit no longer is functioning, and after spending a gret deal of time trying to repair this several years ago I finally abandoned the project.

This unit, although a quality piece of equipment was built like your typical brick shit house, with circuit boards, harnesses, switch banks, etc. "layered" on top of one another. It makes signal tracing, not to mention parts replacement an absolute nightmare. But it does work well on two channel mode so that's how I use it.

I have to say the sound quality assessment of this project was really difficult. As was mentioned by others in the discussion, depending upon where you stand in the room certainly influences the way this sounds. The fact is that every arrangement seemed to sound fairly good. However lacking the proper equipment to scientifically do this, (and if I had wanted to get that technical anyway), the final decision was at best a good guess.

I did notice that with the final setup, that is everything in phase, left and right rears facing fronts from across the room the bass seemed especially strong. In fact standing in the kitchen, two rooms away, I could feel Iron butterfly pounding in my chest. I've never heard sound like this from my system before so I must have done something right.

In fact I was thinking about how good some of my old records were actually sounding. I haven't listened to many of these in quite some time and I noticed that I could hardly hear any scratches. Wow, ttis Stanton cartridge with the elliptical stylus tracking at 1.25 grams must be really something. Then I remembered the results of my last hearing test, which pretty much showed that essentially everything is down almost 40DB above eight KHZ, which essentially translates to "deaf as a doorknob", and I realized that yes they're still scratched. The difference is, I just can't hear it anymore.

Now if I could only upgrade that, so that music could once again sound likeI remember it....Thanks to everyone for your advice and suggestions. Lenny

 

[William Sommerwerck]

"Pat" wrote in message
I was away for a while, so this thread is new to me today. Your
comments above make sense, but bring up a question I have had for many
years. I own a pair of ESS AMT Monitor speakers that I purchased new
back in the 80's. Each has a pair of 12" woofers - one active (ie, a
normal speaker) and the other passive. I would think that when the
active one is compressing the air in the cabinet, the passive one
would be pushed out thereby appearing to be out of phase to a
listener. That doesn't appear to be the case because these speaker
have a great low end sound. Can you explain why they work? (I am
just picking you because you seem to know something about the subject,
but others are welcome to explain my misunderstanding as well.)

The passive radiator is not a radiator in the conventional. It "looks like" a
a volume of air with the same mass. In other words, it's used to create a
ducted-port speaker without the tube. (I think this is the correct
explanation.)

 

[Phil Allison]

"Pat"

"Phil Allison"


I was away for a while, so this thread is new to me today. Your
comments above make sense, but bring up a question I have had for many
years. I own a pair of ESS AMT Monitor speakers that I purchased new
back in the 80's. Each has a pair of 12" woofers - one active (ie, a
normal speaker) and the other passive. I would think that when the
active one is compressing the air in the cabinet, the passive one
would be pushed out thereby appearing to be out of phase to a
listener. That doesn't appear to be the case because these speaker
have a great low end sound. Can you explain why they work? (I am
just picking you because you seem to know something about the subject,
but others are welcome to explain my misunderstanding as well.)

** Using a "passive radiator" is just a variation of the ported enclosure -
it allows a small box to be tuned to a lower frequency and with a larger
radiating surface area than is possible with a conventional port.

Drawbacks are increased cost and non-linearity in the radiator's suspension.

The radiator and the driven cone operate essentially in phase over the
octave above radiator resonance.


..... Phil

 

[William Sommerwerck]

"dave" wrote in message

Why not just put balloons inside a sealed box? Or maybe a hydraulic shock
absorber...

It's been done. William Michael Watson Dayton-Wright built conventional
dynamic speakers with bags of SF6 in the woofer box. He got clean bass to
below 16Hz from a small cabinet.

 

[William Sommerwerck]

"dave" wrote in message

We learned 16 Hz is perceived more as a train of pulses and
less like a sinusoidal tone; it is right on the border of flatulence.

When I put 16Hz through the Watson woofers in my concrete-slab apartment...
//nothing// audible came out of the woofers. But everything in the room
rattled.

 

[Phil Allison]

"William Sommerwerck"

It's been done. William Michael Watson Dayton-Wright built conventional
dynamic speakers with bags of SF6 in the woofer box.

** For what advantage ?

The speed of sound is about half in SF6 but that is no help in a sealed box
where resonance depends only on the stiffness of the volume of gas trapped
behind the woofer.

The smaller the volume or the larger the woofer, the stiffer it becomes.

He got clean bass to below 16Hz from a small cabinet.

** Really ?



..... Phi

 

[William Sommerwerck]

"Phil Allison" wrote in message "William Sommerwerck"

It's been done. William Michael Watson Dayton-Wright built conventional
dynamic speakers with bags of SF6 in the woofer box.

** For what advantage ?

The speed of sound is about half in SF6 but that is no help in a sealed
box where resonance depends only on the stiffness of the volume of
gas trapped behind the woofer.
The smaller the volume or the larger the woofer, the stiffer it becomes.

The lower speed of sound makes the bag appear to have a larger acoustic volume
than the air it replaces.

He got clean bass to below 16Hz from a small cabinet.

** Really?

Really. The bass cabinet was about 20" by 20" by 12". At 16Hz, there was no
/audible/ output from the speaker, but everything loose in the room was
rattling.

The spec sheet for these speakers included a harmonic distortion curve. If I
recall correctly, the speaker had something like 5% harmonic distortion at
20Hz at 90dB output. (Don't hold me to the exact numbers, but the distortion
was very low.)

He also claimed that aluminum wool was a better damping material than
Fibreglas, fiberfill, or foam. He said the linearity of the driver's movement
depended in part on the thermal linearity of the damping material, and that
aluminum wool did a better job. I didn't fully understand this, so don't jump
on me.

Ever heard his SF6-filled electrostatics? We sold a pair to a man with a
large, dead basement. With each speaker powered by bridged Crown M300 amps,
the system could play at ear-splitting levels with no strain.

 

[gregz]

"dave" wrote in message

When I put 16Hz through the Watson woofers in my concrete-slab
apartment... //nothing// audible came out of the woofers. But everything
in the room rattled.

I used to rattle things in my old basement. It resonated around 30 hz, but
16 hz will shake things. With 30 hz in the basement, you had to be in the
right spots to hear or not hear 30 hz.

Greg

 

[Phil Allison]

"William Sommerwanker"

"Phil Allison"

** For what advantage ?

The lower speed of sound makes the bag appear to have a larger acoustic
volume than the air it replaces.

** You have simply ignored question, which is the stiffness of a fixed
volume of gas.

Take a look at Boyle's Law ( PV = k )

Really. The bass cabinet was about 20" by 20" by 12".

** That is not a "small cabinet" at circa 50 litres internal volume.

Had an 15 inch woofer fitted - did it ?

At 16Hz, there was no /audible/ output from the speaker, but everything
loose in the room was rattling.

** Standing waves are a real bitch........

Ever heard his SF6-filled electrostatics?

** Now that was done for an entirely different reason.



..... Phil

 

[William Sommerwerck]

I'm giving a respectful response, despite being called Sommerwanker. Shall I
start calling you Anuson?

The lower speed of sound makes the bag appear to have a larger acoustic
volume than the air it replaces.

** You have simply ignored the question, which is the stiffness of a fixed
volume of gas.

Take a look at Boyle's Law (PV = k)

As Michael Flanders put it... "The greater the pressure, the larger the volume
of hot air."

I found the spec sheet. He describes the SF6 as performing a linearizing
function. He says nothing about increasing the cabinet's "apparent" volume.
I'll call a friend who designs speakers and have him put me right -- if such
needs be done.

Really. The bass cabinet was about 20" by 20" by 12".

** That is not a "small cabinet" at circa 50 litres internal volume.

I consider it "small", as it was the bottom structure of a floor-standing
speaker. That's not a large enclosure for a speaker that gets to 20Hz and
lower with low distortion.

Had an 15 inch woofer fitted -- did it ?

Nope. Two oddball 10" drivers -- with pie plates glued to them! See the photo.

At 16Hz, there was no /audible/ output from the speaker, but everything
loose in the room was rattling.

** Standing waves are a real bitch...

Oh, I walked around to see if I could hear any subsonic output. There was
none. Assuming you believe the spec sheet, note the ridiculously low LF
distortion.

Ever heard his SF6-filled electrostatics?

** Now that was done for an entirely different reason.

 

[William Sommerwerck]

I just found the following quote:

"Only the woofer/subwoofer were not bipolar. These relied in the use of SF6
(sulfur hexafluoride) gas (which is inert), to increase the virtual volume of
the enclosure. As SF6 is an 'ideal gas', it operates as an 'isothermal'
spring, thus avoiding the problems with 'acoustic-suspension' loudspeakers
that operated partially as an isothermal and partially as an adiabatic system.
Some designers seemed to lave little knowledge of Boyles Law or the Laws of
Thermodynamics.

"In effect, the use of SF6, increases the virtual volume of the enclosure by a
factor of 27! As can be appreciated, this both lowers the distortion as well
as permitting a lower resonant frequency of the woofer."

It's here...

http://www.dayton-wright.com/WATSONLABS_.html

I should point out that the bass cabinet is not completely filled with SF6. If
I recall correctly, the gas bags were separated with foam sheets.

 

[Phil Allison]

"William Sommerwerck"

** You have simply ignored the question, which is the stiffness of a fixed
volume of gas.

Take a look at Boyle's Law (PV = k)

As Michael Flanders put it...

** You have ignored the question AGAIN !!!!!

I found the spec sheet. He describes the SF6 as performing a linearizing
function.

** Pure marketing hype.

** That is not a "small cabinet" at circa 50 litres internal volume.

I consider it "small",

** Yawnnnnnnnnnnnnnnnnn....

It is not small - a 10 litre box is small.

And Boyle's law makes all the claims re SF6 all wrong.



..... Phil

 

[Phil Allison]

"William Sommerwerck"

I just found the following quote:

** I found it two days ago and roared laughing.

It is the greatest pile of * bullshit * I have ever seen about woofers.

"Only the woofer/subwoofer were not bipolar. These relied in the use of
SF6 (sulfur hexafluoride) gas (which is inert), to increase the virtual
volume of the enclosure. As SF6 is an 'ideal gas', it operates as an
'isothermal' spring, thus avoiding the problems with 'acoustic-suspension'
loudspeakers that operated partially as an isothermal and partially as an
adiabatic system. Some designers seemed to lave little knowledge of Boyles
Law or the Laws of Thermodynamics.

"In effect, the use of SF6, increases the virtual volume of the enclosure
by a factor of 27! As can be appreciated, this both lowers the distortion
as well as permitting a lower resonant frequency of the woofer."

It's here...

http://www.dayton-wright.com/WATSONLABS_.html

** Marketing hype - not engineering fact.

The very next line is soooo telling:

" But to use this, a larger cone mass is needed and the suspension has to be
much more compliant."

Cos it contradicts the rest of the hype.

If SF6 worked as claimed, standard woofers would be all that was needed.

It doesn't.



..... Phil

 

[William Sommerwerck]

Unfortunately, Mr Anuson, I owned these speakers and can vouch for their
performance.

Mr Anuson, name a brand and model of woofer, of the volume given, that can get
down to 16Hz with such low distortion. I'm waiting...

It's impossible to have any kind of a discussion -- you know everything.
You're polite when people agree with you, and a vicious -- I can't think of
anything bad enough -- when they don't.