Speaker Design

[[email protected]]

Of all the electronic items made over the years, the one that appears to
have changed the least is the speaker. They have always been pretty
much the same. Originally they used electro magnets, then changed to
fixed magnets. The cones have used different materials, but mostly
paper and plastics, some with a foam at the edges. There was a time
when a small cone was added to the middle of a large speaker to act as a
tweeter, although they were not very effective and is no longer in use.
The coils have always been pretty much the same. I see little change in
speakers in the future, other than the trend seems to be smaller
speakers which can still deliver high power. However there seems to be
limitations on sound quality with smaller speakers. Also, plastic
cabinets will never replace real wood, and never sound (or look) as good
as wood.

The one thing that I have noticed are the Bose speakers. From what I
read, they use an enclosure which directs the sound in a way that causes
air pressure to move inside a room, and thus makes more powerful bass
from their sub-woofers. From what I understand, the speaker itself is
the same, but the cabinet is different. It's capable of delivering more
bass from less speaker size.

It appears that Bose is very closed mouthed about how they achieve this.
Their speakers are probably the most expensive available, so it makes
sense that they keep secret how they design these cabinets. My reason
in posting this is because someone must know how they do it. But I have
not been able to find anything on the web.

Does anyone know of any websites that explain in detail how they design
their enclosures (cabinets), and what is used? I have always built my
own speaker cabinets, and would like to try a similar design.

Thanks

 

[[email protected]]

Of all the electronic items made over the years, the one that appears to
have changed the least is the speaker. They have always been pretty
much the same. Originally they used electro magnets, then changed to
fixed magnets. The cones have used different materials, but mostly
paper and plastics, some with a foam at the edges. There was a time
when a small cone was added to the middle of a large speaker to act as a
tweeter, although they were not very effective and is no longer in use.
The coils have always been pretty much the same. I see little change in
speakers in the future, other than the trend seems to be smaller
speakers which can still deliver high power. However there seems to be
limitations on sound quality with smaller speakers. Also, plastic
cabinets will never replace real wood, and never sound (or look) as good
as wood.

Fractional horsepower motors haven't changed much in a hundred years, either.
Probably for the same reasons. A speaker *is* a motor, after all. ;-)

The one thing that I have noticed are the Bose speakers. From what I
read, they use an enclosure which directs the sound in a way that causes
air pressure to move inside a room, and thus makes more powerful bass
from their sub-woofers. From what I understand, the speaker itself is
the same, but the cabinet is different. It's capable of delivering more
bass from less speaker size.

More midrange, anyway. They aren't very good speakers.

It appears that Bose is very closed mouthed about how they achieve this.
Their speakers are probably the most expensive available, so it makes
sense that they keep secret how they design these cabinets. My reason
in posting this is because someone must know how they do it. But I have
not been able to find anything on the web.

They're just folded horns, AIUI. They do have a bunch of patents but mostly,
no one wants to make sound like them. They sure don't sound that good to me,
particularly for the price they want.

Does anyone know of any websites that explain in detail how they design
their enclosures (cabinets), and what is used? I have always built my
own speaker cabinets, and would like to try a similar design.

You're probably out of luck if you want to copy Bose. I think you'll need
simulation to match them. I'm sure the formulas for more "normal" speaker
enclosures are on the net somewhere.

 

[Nico Coesel]

The one thing that I have noticed are the Bose speakers. From what I

Bose = crappy speaker and a signal processing unit to make it sound
'right'.

 

[Phil Allison]

Of all the electronic items made over the years, the one that appears to
have changed the least is the speaker.

** The AC supply transformer has changed the least.

They have always been pretty much the same.

** Could say that about the automobile - still have four wheels and an
internal combustion engine.

Originally they used electro magnets, then changed to
fixed magnets. The cones have used different materials, but mostly
paper and plastics, some with a foam at the edges. There was a time
when a small cone was added to the middle of a large speaker to act as a
tweeter, although they were not very effective and is no longer in use.

** Twin cone speakers are still around, common in ceiling speakers for BGM
and paging.

The coils have always been pretty much the same.

** Hard to beat copper wire - but some makers are using CCA or Cooper Clad
Aluminium wire.

I see little change in speakers in the future,

** You have not noticed the major changes over that last 50 years.

Dome tweeters and mid units were not always around.

The one thing that I have noticed are the Bose speakers.

** Strewth !! So he notices giant leaps backwards ??

From what I
read, they use an enclosure which directs the sound in a way that causes
air pressure to move inside a room, and thus makes more powerful bass
from their sub-woofers. From what I understand, the speaker itself is
the same, but the cabinet is different. It's capable of delivering more
bass from less speaker size.

It appears that Bose is very closed mouthed about how they achieve this.

** If you are alluding to the "Acoustimas" - that is no secret at all. Its
a "bandpass" box, probably 8th order.

Other designs have uses simple porting or long pipes and Bose are famous for
using custom equalisers in the amplifier chain - eg in the 901 and 801
series.

Worst speaker idea ever thought of.

Does anyone know of any websites that explain in detail how they design
their enclosures (cabinets), and what is used? I have always built my
own speaker cabinets, and would like to try a similar design.

** Or you could aim higher ...


..... Phil

 

[amdx]

Of all the electronic items made over the years, the one that appears to
have changed the least is the speaker. They have always been pretty
much the same. Originally they used electro magnets, then changed to
fixed magnets. The cones have used different materials, but mostly
paper and plastics, some with a foam at the edges. There was a time
when a small cone was added to the middle of a large speaker to act as a
tweeter, although they were not very effective and is no longer in use.
The coils have always been pretty much the same. I see little change in
speakers in the future, other than the trend seems to be smaller
speakers which can still deliver high power. However there seems to be
limitations on sound quality with smaller speakers. Also, plastic
cabinets will never replace real wood, and never sound (or look) as good
as wood.

The one thing that I have noticed are the Bose speakers. From what I
read, they use an enclosure which directs the sound in a way that causes
air pressure to move inside a room, and thus makes more powerful bass
from their sub-woofers. From what I understand, the speaker itself is
the same, but the cabinet is different. It's capable of delivering more
bass from less speaker size.

It appears that Bose is very closed mouthed about how they achieve this.
Their speakers are probably the most expensive available, so it makes
sense that they keep secret how they design these cabinets. My reason
in posting this is because someone must know how they do it. But I have
not been able to find anything on the web.

Does anyone know of any websites that explain in detail how they design
their enclosures (cabinets), and what is used? I have always built my
own speaker cabinets, and would like to try a similar design.

Thanks

Back 20+ years ago when I worked in electronic service, I recall the
Bose 901 speaker had 8 or 9, small speakers (4" or 5") in series.
The rep once said the hooked one up to the 120 volt AC outlet and it
played until it shook a wire loose from one of the speakers, it still
worked after repairing the broken wire.
Mikek

 

[Phil Allison]

"amdx"

Back 20+ years ago when I worked in electronic service, I recall the Bose
901 speaker had 8 or 9, small speakers (4" or 5") in series.

** All the drivers have 1 ohm voice coils and the cabinets were tuned to
about 60Hz.

Earlier versions used 8 ohm drivers wired in series parallel.

The rep once said the hooked one up to the 120 volt AC outlet and it
played until it shook a wire loose from one of the speakers, it still
worked after repairing the broken wire.

** Did the Bose rep really say that ?

Amasing ....



..... Phil

 

[amdx]

"amdx"


** All the drivers have 1 ohm voice coils and the cabinets were tuned to
about 60Hz.

Earlier versions used 8 ohm drivers wired in series parallel.


** Did the Bose rep really say that ?

Amasing ....



.... Phil

Yes.

I can't vouch for the truth of his story, just that he said it.

Mikek

 

[[email protected]]

Back 20+ years ago when I worked in electronic service, I recall the
Bose 901 speaker had 8 or 9, small speakers (4" or 5") in series.
The rep once said the hooked one up to the 120 volt AC outlet and it
played until it shook a wire loose from one of the speakers, it still
worked after repairing the broken wire.
Mikek

Yea, but hooked to 120 volts AC, what's it going to play? 60hz hum is
about all it could emit, and by that time, every coil would be glowing
red from the heat, and the cones would burn up. Somehow I dont buy into
this...... Sounds like a folk-tale to make sales. I'd be more likely
to believe it being connected to a 1000w amplifier or something like
that.....

 

[Phil Allison]

"amdx"

"amdx"

Yes.

I can't vouch for the truth of his story, just that he said it.

** The story might even be true.

With the divers all wired in SERIES, if a feed wire on any one failed, or as
more likely the case here simply BURNED OUT - all sound stops.

The lie is that it lasted more than two seconds.


..... Phil

 

[[email protected]]

Fractional horsepower motors haven't changed much in a hundred years, either.
Probably for the same reasons. A speaker *is* a motor, after all. ;-)

I was thinking more in terms of electronic components. whereas an
electric motor is more of an electric device. However you're correct,
in that motors have not changed much over the years.

I sure can't think of any other way to convert electrical energy into
horsepower attached to the end of a rotating shaft. It's kind of odd,
when you think that modern motors are built smaller for their HP rating,
much due to better insulator materials, compared to the old enamel and
cloth used on the old motors. Yet, the old motors seem to outlast most
of the newer ones.

Of course, much of this is planned. Im years past, products were built
to last, and engineers were educated to design better and longer lasting
products. These days, products are built to make a fast buck, and
engineers are educated to design products which make the biggest buck
and fail shortly after the warranty ends, so they can make another fast
buck.

 

[Phil Allison]

I was thinking more in terms of electronic components.

** Speakers are **NOT** electronic components.

You fucking PITA tenth wit.




.... Phil

 

[amdx]

Yea, but hooked to 120 volts AC, what's it going to play? 60hz hum is
about all it could emit, and by that time, every coil would be glowing
red from the heat, and the cones would burn up. Somehow I dont buy into
this...... Sounds like a folk-tale to make sales. I'd be more likely
to believe it being connected to a 1000w amplifier or something like
that.....

I think the story needs to be verified.
Who has some 901's?
Mikek

 

[Spehro Pefhany]

I think the story needs to be verified.
Who has some 901's?
Mikek

The 901 manual says it's "compatible" with receivers up to 450W RMS
(sic), but gives the speaker rating as "250W IEC", so presumably
rather less than 250W continuous.

120VAC across the nominal 8 ohm impedance is 1800W. The Z might be a
bit higher at 60Hz, but still, it's gonna break or fry either
immediately or in pretty short order.


Best regards,
Spehro Pefhany

 

[Chieftain of the Carpet Crawlers]

Of course, much of this is planned. Im years past, products were built
to last, and engineers were educated to design better and longer lasting
products. These days, products are built to make a fast buck, and
engineers are educated to design products which make the biggest buck
and fail shortly after the warranty ends, so they can make another fast
buck.

Nice bent perception of reality you've got there.

 

[Spehro Pefhany]

The 901 manual says it's "compatible" with receivers up to 450W RMS
(sic), but gives the speaker rating as "250W IEC", so presumably
rather less than 250W continuous.

120VAC across the nominal 8 ohm impedance is 1800W. The Z might be a
bit higher at 60Hz, but still, it's gonna break or fry either
immediately or in pretty short order.

Hmm.. okay, suppose the Z at 60Hz is actually more like 12 ohms, and
they connected the speakers in series-- that's 600W. I might believe
they would survive that for a few unpleasant seconds.



Best regards,
Spehro Pefhany

 

[amdx]

Hmm.. okay, suppose the Z at 60Hz is actually more like 12 ohms, and
they connected the speakers in series-- that's 600W. I might believe
they would survive that for a few unpleasant seconds.



Best regards,
Spehro Pefhany

Is that the manual that came with your speakers?
If yes, how about measuring the impedance of the speaker.
Mikek

 

[Chieftain of the Carpet Crawlers]

how about measuring the impedance of the speaker.
Mikek

What is your special "accurate" method for that?

Hint: It ain't an ohmmeter readout.

 

[Fred Abse]

I was thinking more in terms of electronic components. whereas an
electric motor is more of an electric device.

And electronic components are not?

Steam powered maybe ;-)

 

[amdx]

What is your special "accurate" method for that?

Hint: It ain't an ohmmeter readout.

I'd use a .1 ohm resistor on the low side in series with the speaker
and drive it with my signal generator at 60 hz. Then I'd measure the
voltage drop across the 0.1 ohm resistor and voltage across the speaker
with my scope. Then calculate from there.
I could do it at the shop and run a graph of R and XL and have the
computer calculate and graph the impedance.
But, all I want to know is the impedance a 60hz.

But since you ask the question, you must think your a fucking genius.
Mikek

 

[[email protected]]

I was thinking more in terms of electronic components. whereas an
electric motor is more of an electric device. However you're correct,
in that motors have not changed much over the years.

But a speaker is nothing more than a linear motor. There have been some
improvements, but mostly materials (rare earth magnets, and such).

I sure can't think of any other way to convert electrical energy into
horsepower attached to the end of a rotating shaft. It's kind of odd,
when you think that modern motors are built smaller for their HP rating,
much due to better insulator materials, compared to the old enamel and
cloth used on the old motors. Yet, the old motors seem to outlast most
of the newer ones.

They're smaller, mostly because they're engineered closer to the edge. They
don't last as long for similar reasons.

Of course, much of this is planned. Im years past, products were built
to last, and engineers were educated to design better and longer lasting
products. These days, products are built to make a fast buck, and
engineers are educated to design products which make the biggest buck
and fail shortly after the warranty ends, so they can make another fast
buck.

No, it's more an issue of cost. There would be no market for a washing
machine with a better motor if it cost $100 more. For one thing, motors
rarely fail, now. For another, the competition will beat you to a pulp.