Chip with simple program for Toy

[John Larkin]

On Sun, 26 Jan 2014 05:07:02 +0000 (UTC), Kaz Kylheku <kaz@kylheku.com> wrote:

Excerpt From my LTspiceIV.ini file:

The only function key is F5: run simulation. (Old Visual Studio braindamage.)

[SchKeyBoardShortCut]
Place_Component=I
Draw_Wire_Mode=W
Place_Netname=N
Delete_Mode=Ctrl+D
Duplicate_Mode=Ctrl+C
Move_Mode=,
Drag_Mode=.
Undo=Ctrl+Z
Redo=Ctrl+Shift+Z
Place_Comment_Text=T
Place_SPICE_Directive=S
Unconn_Pin_Marks=U
Text_Anchor_Marks=A
Place_Ground=G
Place_Resistor=R
Place_Capacitor=C
Place_Inductor=L
Place_Diode=D
Draw_Lines=(none)
Draw_Rectangles=(none)
Draw_Circles=(none)
Draw_Arcs=(none)
Reset_T_0=0 )
Schematic_Grid=Shift+3 #
Rotate=Shift+/ ?
Mirror=/ ?
Zoom_Area=O
Zoom_Back=- _
Halt_Simulation=Shift+F5
Run_Simulation=F5
Place_BUS_Tap=B
Zoom_to_Fit=Space
View_SPICE_Error_Log=Ctrl+L
[AsyKeyBoardShortCut]
Object_Anchors=O
Place_Pin=P
Delete_Mode=Ctrl+D
Duplicate_Mode=Ctrl+C
Move_Mode=Shift+,
Drag_Mode=Shift+.
Undo=Ctrl+Z
Redo=Ctrl+Shift+Z
Place_Comment_Text=T
Draw_Lines=L
Draw_Rectangles=R
Draw_Arcs=A
Draw_Circles=C
Rotate=Shift+/ ?
Mirror=/ ?
Attribute_Editor=(none)
Attribute_Window=(none)
Zoom_Back=- _
Zoom_In=(none)
Show_Pin_Table=(none)
[RawKeyBoardShortCut]
Zoom_Extents=E
Zoom_Area=O
Zoom_Back=- _
Vertically_Autorange=Y
Toggle_Grid=Shift+3 #
Delete_Mode=Ctrl+D
Add_Trace=T
Add_Pane=P
Undo=Ctrl+Z
Redo=Ctrl+Shift+Z
Run_Simulation=F5
Halt_Simulation=Shift+F5
Open_Plot_Settings_File=(none)
Reload_Plot_Settings_File=(none)
Label_cursor_position=(none)
Place_text_on_the_plot=(none)
Draw_an_arrow_on_the_plot=(none)
Draw_a_line_on_the_plot=(none)
Draw_a_box_on_the_plot=(none)
Draw_a_circle_on_the_plot=(none)
Annotation_Line_Style/Color=(none)
Move_Plot_Annotations=(none)
Drag_Plot_Annotations=(none)
Redraw_Window=(none)
Select_Steps=(none)
View_SPICE_Error_Log=Ctrl+L
[NetKeyBoardShortCut]
Goto_Line_Number=Ctrl+G
Run_Simulation=F5
Pause_Simulation=(none)
Halt_Simulation=Shift+F5
Undo=Ctrl+Z
Redo=Ctrl+Shift+Z
View_SPICE_Error_Log=Ctrl+L

Spacebar is cool; it resizes the schematic.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation

 

[Jeff Liebermann]

On Sun, 26 Jan 2014 14:26:34 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Yeah, 4046es still have that problem. Usually a 1 M resistor from PD2
output to ground fixes it, because all you have to do is pull the
quiescent point a few nanoseconds from the null.

To the best of my limited knowledge, it's a problem with all digital
phase detectors. Anything that goes tri-state (i.e. open circuit
output) when locked is going to have a dead band. I found that out
the hard way when I tried to replace the 11C44 with a D flip-flop
equivalent, and had the same problem.

Using a large value resistor was one of the first things we tried. The
problem was that any offset in the loop amplifier would dramatically
increase the reference oscillator feedthrough.

The 1M resistor is also a problem in marine radios. One just does not
use large value resistors in a marine environment. The largest value
I used was 470K for a microphone amp, where PCB leakage was not
important. Otherwise, about 100K was as large as I would consider
safe. Someone will surely suggest conformal coating. We did some of
that but the inability to apply it consistently, even with UV
additives, caused problems. Connectors had to be masked, and rework
was difficult and messy. No thanks. Incidentally, we also pioneered
(with Piezo Technologies) the use of low impedance crystal filters for
much the same reasons.

What we did to "solve" the low frequency noise and rumble problem was
rather uninspiring. We discovered that 11C44 chips from one country
would have a smaller dead band than other. Those were selected for
the more critical HF radio synthesizers. It turned out that only one
loop was really critical making selecting parts tolerable. Next, the
audible noise was removed by high pass filters in the audio circuitry.
The trick was keeping the noise below 300 Hz, which proved fairly easy
by tweaking the PLL constants. This also had the added benefits of
reducing the audible "clunk" whenever the frequency was changed and
reducing microphonics[1]. Lastly, the selection of the loudspeaker
and the acoustic design of the box, was designed to reduce the low
frequencies, mostly to prevent oscillations due to microphonics.


[1] Microphonics are produced by beating on the case, or yelling into
the enclosure, which modulates the PLL. This can be heard on the TX
and RX audio. In extreme cases, the loudspeaker audio modulates the
VCO, causing audio oscillation.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Kaz Kylheku]

On 2014-01-26, John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sun, 26 Jan 2014 05:07:02 +0000 (UTC), Kaz Kylheku <kaz@kylheku.com> wrote:
Zoom_to_Fit=Space

Spacebar is cool; it resizes the schematic.

Yes; and that is the default keybinding. Didn't touch that one.

 

[Jeff Liebermann]

On Sun, 26 Jan 2014 16:53:41 -0500, Michael Black <et472@ncf.ca>
wrote:

On Sun, 26 Jan 2014, Jeff Liebermann wrote:


SN74196N Presetable 4-Bit Binary Counter

Decadence counter (divide by 10):
http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=sn74196&fileType=pdf
Maximum clock freq of 50 MHz. You'll need at least one 74196 for
every digit on the display.

No, just for the least significant digit. Since it did go to 50MHz or so,
the output is then in the 5MHz range, perfect for the slower ttl or
whatever is used. If it is low integration and using
counter/latch/decoder ICs for each digit, then the rest of the counters
can be the so common 7490.

Agreed. My error was assuming that Mike had listed all the IC's in
the counter. He later mentioned that there was a "display board"
which probably contains the counter chain ICs, probably 7490 decade
counter ICs. I assumed that the dividers were all 74196 which is why
I expected to see one for each digit.

That was the neat thing. When the 74196 came along (or maybe just someone
ralized it, I'm not sure when it came out), just by changing some wiring
one could improve the count of an existing counter.

Michael

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Maynard A. Philbrook Jr.]

In article <ln2be9drleuqmr7fnh7s477h0npe5ht300@4ax.com>,
jeffl@cruzio.com says...

[1] Microphonics are produced by beating on the case, or yelling into
the enclosure, which modulates the PLL. This can be heard on the TX
and RX audio. In extreme cases, the loudspeaker audio modulates the
VCO, causing audio oscillation.

I had an amp that had a microphonic problem. It turned out to
be a through hole transistor of a common variety that had a
loose element inside and it just happen to be in the preamp
section.

It was a guitar amplifier head and it would squeal like
hell as soon as you turned it up..

Jamie

 

[Phil Hobbs]

On 1/26/2014 5:50 PM, Jeff Liebermann wrote:

On Sun, 26 Jan 2014 14:26:34 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Yeah, 4046es still have that problem. Usually a 1 M resistor from PD2
output to ground fixes it, because all you have to do is pull the
quiescent point a few nanoseconds from the null.

To the best of my limited knowledge, it's a problem with all digital
phase detectors. Anything that goes tri-state (i.e. open circuit
output) when locked is going to have a dead band. I found that out
the hard way when I tried to replace the 11C44 with a D flip-flop
equivalent, and had the same problem.

There are a variety of ways of getting round it. The Motorola way is to
have separate up and down outputs, both of which have a nonzero width
when the phase error is zero. With that approach, there are two regions
where the slope is reduced, but neither of them is where the loop wants
to servo. Pulling the loop slightly to one side makes it easier.

Using a large value resistor was one of the first things we tried. The
problem was that any offset in the loop amplifier would dramatically
increase the reference oscillator feedthrough.

If you're relying on the pulse width going to zero to meet your ripple
spec, then yes, you're going to have to servo on the flat spot. That's
a design error, however.

The 1M resistor is also a problem in marine radios. One just does not
use large value resistors in a marine environment. The largest value
I used was 470K for a microphone amp, where PCB leakage was not
important. Otherwise, about 100K was as large as I would consider
safe. Someone will surely suggest conformal coating. We did some of
that but the inability to apply it consistently, even with UV
additives, caused problems. Connectors had to be masked, and rework
was difficult and messy. No thanks. Incidentally, we also pioneered
(with Piezo Technologies) the use of low impedance crystal filters for
much the same reasons.

There's nothing special about 1M. It just has to be enough to pull the
servo point a few nanoseconds off the flat spot. If the rest of the
loop filter is lower-Z, 100k would probably do it. You just have to
design it.

What we did to "solve" the low frequency noise and rumble problem was
rather uninspiring. We discovered that 11C44 chips from one country
would have a smaller dead band than other. Those were selected for
the more critical HF radio synthesizers. It turned out that only one
loop was really critical making selecting parts tolerable. Next, the
audible noise was removed by high pass filters in the audio circuitry.
The trick was keeping the noise below 300 Hz, which proved fairly easy
by tweaking the PLL constants. This also had the added benefits of
reducing the audible "clunk" whenever the frequency was changed and
reducing microphonics[1]. Lastly, the selection of the loudspeaker
and the acoustic design of the box, was designed to reduce the low
frequencies, mostly to prevent oscillations due to microphonics.

That's pretty much turd-polishing. If you come into a project late,
sometimes you have to do that sort of thing, but nobody likes it.

Microphonics are produced by beating on the case, or yelling into
the enclosure, which modulates the PLL. This can be heard on the TX
and RX audio. In extreme cases, the loudspeaker audio modulates the
VCO, causing audio oscillation.

Mechanical sensitivity of oscillators is a pretty well known problem, I
agree. Bumping up the loop bandwidth helps a lot.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

[Jeff Liebermann]

On Sun, 26 Jan 2014 18:47:05 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 1/26/2014 5:50 PM, Jeff Liebermann wrote:
On Sun, 26 Jan 2014 14:26:34 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

Yeah, 4046es still have that problem. Usually a 1 M resistor from PD2
output to ground fixes it, because all you have to do is pull the
quiescent point a few nanoseconds from the null.

To the best of my limited knowledge, it's a problem with all digital
phase detectors. Anything that goes tri-state (i.e. open circuit
output) when locked is going to have a dead band. I found that out
the hard way when I tried to replace the 11C44 with a D flip-flop
equivalent, and had the same problem.

There are a variety of ways of getting round it. The Motorola way is to
have separate up and down outputs, both of which have a nonzero width
when the phase error is zero. With that approach, there are two regions
where the slope is reduced, but neither of them is where the loop wants
to servo. Pulling the loop slightly to one side makes it easier.

I hadn't heard of that method. Good idea and sounds like it would
work. I wish I had thought of it. (Note: I was about 25 years old
at the time and thought I knew everything there was to know).

Using a large value resistor was one of the first things we tried. The
problem was that any offset in the loop amplifier would dramatically
increase the reference oscillator feedthrough.

If you're relying on the pulse width going to zero to meet your ripple
spec, then yes, you're going to have to servo on the flat spot. That's
a design error, however.

Guilty as charged for using the 11C44 in the manufacturers prescribed
manner. I wanted to replace it with a double balanced mixer (SBL-1)
as a phase detector, but never could get rid of the DC offset or keep
it linear. The SBL-1 was chosen mostly because it was already being
used in the dual loop synthesizer as a mixer. When I was done with
that diversion, patching the problem with high pass filters was the
best I could contrive in the time remaining. If I had known about the
Motorola trick, I would certainly have tried it.

There's nothing special about 1M. It just has to be enough to pull the
servo point a few nanoseconds off the flat spot. If the rest of the
loop filter is lower-Z, 100k would probably do it. You just have to
design it.

I just took a closer look at the schematic. The low frequency PLL
that supplied the 2nd LO frequency is a 4046 with a 10M resistor
pullup. It's an early manual and that was later removed.

What we did to "solve" the low frequency noise and rumble problem was
rather uninspiring. We discovered that 11C44 chips from one country
would have a smaller dead band than other. Those were selected for
the more critical HF radio synthesizers. It turned out that only one
loop was really critical making selecting parts tolerable. Next, the
audible noise was removed by high pass filters in the audio circuitry.
The trick was keeping the noise below 300 Hz, which proved fairly easy
by tweaking the PLL constants. This also had the added benefits of
reducing the audible "clunk" whenever the frequency was changed and
reducing microphonics[1]. Lastly, the selection of the loudspeaker
and the acoustic design of the box, was designed to reduce the low
frequencies, mostly to prevent oscillations due to microphonics.

That's pretty much turd-polishing. If you come into a project late,
sometimes you have to do that sort of thing, but nobody likes it.

Also guilty as charged. Nobody liked it including me. However, the
deadline (San Mateo Cow Palace Boat Show) was looming and marketing
wanted to demonstrate a working radio. As it turned out, the
marketing manager took it with him on an airplane flight to Florida to
show some dealers and managed to misplace it for a while at a hotel.
When the prototype finally returned to California, it was too late for
the boat show. A fair number of people in engineering gave up
weekends and evenings for that fiasco and were not amused. As it
turned out, I did get another chance to fix things as there were also
production problems. However, they were in other areas and the phase
detector problems were not addressed.

Microphonics are produced by beating on the case, or yelling into
the enclosure, which modulates the PLL. This can be heard on the TX
and RX audio. In extreme cases, the loudspeaker audio modulates the
VCO, causing audio oscillation.

Mechanical sensitivity of oscillators is a pretty well known problem, I
agree. Bumping up the loop bandwidth helps a lot.

That helps as long as I don't have to FM modulate the PLL. The PLL
should NOT follow the modulation which means that the loop bandwidth
has to be lower than the lowest expected modulation frequency (about
300 Hz). The initial design of the synthesizer was not my project, so
I don't have any design notes with which to check. I could probably
calculate the loop bandwidth from the schematic.

Microphonics is much less of a problem today because of crystal can
and SMT VCO's, which are far less susceptible to vibration than the
old discrete versions.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Phil Allison]

"Jasen Bleatts" <jasen@xnet.co.nz>

smooth curves are good, because they withstand pressure differences
without deforming.

Would the enclosure need to be perforated?

To port or not to port..

** FFS Jasen - get a damn dictionary !!!!!!!!!

As I understand, it's a loudness vs fidelity
trade-off.

** LOL !!!

You ? Understand ? ANYthing ????

Even the sheep are laughing out loud.

Fuckwits like YOU should only ask questions here.

NOT POSTING FUCKING STUPID REPLIES
--------------------------------------------------------




..... Phil

 

[Bob Masta]

On Tue, 28 Jan 2014 13:51:06 -0800, etpm@whidbey.com wrote:

This speaker question kinda goes with my previous question(s) about
tubes. I have been looking at tube stuff on the web and some of it
really appeals to me. I'm a machinist and have a shop so making knobs
and the like is easy for me to do. And some of the tube sets with
exposed tubes and transformers sure are pretty. So I got to thinking
about speakers. I would like to have metal enclosures (cans really)
for the speakers that follow the shape of the speaker. Each speaker
would then be mounted on its own pole. Or maybe three speakers,
mounted vertically, on a pole. The enclosures would be nickel plated.
Probably brass, because I can spin brass. Nickel plate it too. I've
got the stuff. The enclsures should also have some sort of nickel
plated grille too. I know it sounds ridicolous, but the idea appeals
to me. Could I get good sound with the enclosures I'm describing?
Would the enclosure need to be perforated? Shoul I just get a life?
Thanks,
Eric

Defintely do NOT make the enclosures from metal, or anything
resonant. The best material is actually one of the
cheapest: Particle board. Usually Medium Density Fiberboard
(MDF) is recommended, but any flake or chip composite will
probably be OK. (High density is also good.)

As for your thought about following the shape of the
speaker, the enclosure shape is not terribly critical, but
the volume is. There are two basic design types: sealed box
or ported box. (Omitting exotics like horns and
transmission lines.) In either case, the design box volume
is related to mechanical properties of the woofer, such as
the free-air resonance frequency and the compliance or
"springiness" of the suspension. Those can be gotten from
the supplier for most of the better brands, but they can
also be measured with fairly simple equipment. Then you
plug them into a formula that tells you the ideal box
volume.

Ported speakers have an additional variable. Instead of the
box being sealed, there is a "port" in it which is typically
tuned by having a heavy cardboard tube behind it. The
general idea is that the speaker and box combo has a
resonant frequency below which sound output falls off
quickly. The port can effectively move it down a bit. It
also increases bass output by radiating the lower
frequencies itself.

So back to your quest: You can do a full design job using
speaker parameters (or measurements) and equations (or
software), build a nice MDF box, and *then* cover it with
metal... or anything else. (Many people opt for fancy wood
veneer, but a cheap, simple, and attractive alternative is
upholstery fabric. It can be chosen to go with the room
decor (and easily changed later), and you can put it on with
a staple gun and some careful folding.)

Note that box design only pertains to the low-frequency
response of the woofer, but most speakers also have a
tweeter, or a tweeter and midrange (or multiple). The
tweeter/midrange needs to be matched to the upper end of the
woofer response, or (more typically) a "crossover" network
is used to low-pass filter the woofer and high-pass filter
the tweeter/midrange so the overall response is reasonably
flat. The crossover is thus an important comonent in the
overall system.

So the other way you can approach this is to buy a speaker
you like (actually a speaker system, including enclosure ,
woofer, tweeter, crossover, etc) and then cover it with
metal.

Or buy a kit from a supplier, which will typically have all
the parts (sometimes without the enclosure, just
construction plans). Follow their plans exactly and then
cover the enclosure with metal, OR come up with your own
enclosure design that has the exact same interior volume as
specified.

Best regards,


Bob Masta

DAQARTA v7.50
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusiq generator
Science with your sound card!

 

On Wed, 29 Jan 2014 13:52:43 GMT, N0Spam@daqarta.com (Bob Masta)
wrote:

On Tue, 28 Jan 2014 13:51:06 -0800, etpm@whidbey.com wrote:

This speaker question kinda goes with my previous question(s) about
tubes. I have been looking at tube stuff on the web and some of it
really appeals to me. I'm a machinist and have a shop so making knobs
and the like is easy for me to do. And some of the tube sets with
exposed tubes and transformers sure are pretty. So I got to thinking
about speakers. I would like to have metal enclosures (cans really)
for the speakers that follow the shape of the speaker. Each speaker
would then be mounted on its own pole. Or maybe three speakers,
mounted vertically, on a pole. The enclosures would be nickel plated.
Probably brass, because I can spin brass. Nickel plate it too. I've
got the stuff. The enclsures should also have some sort of nickel
plated grille too. I know it sounds ridicolous, but the idea appeals
to me. Could I get good sound with the enclosures I'm describing?
Would the enclosure need to be perforated? Shoul I just get a life?
Thanks,
Eric

Defintely do NOT make the enclosures from metal, or anything
resonant. The best material is actually one of the
cheapest: Particle board. Usually Medium Density Fiberboard
(MDF) is recommended, but any flake or chip composite will
probably be OK. (High density is also good.)

As for your thought about following the shape of the
speaker, the enclosure shape is not terribly critical, but
the volume is. There are two basic design types: sealed box
or ported box. (Omitting exotics like horns and
transmission lines.) In either case, the design box volume
is related to mechanical properties of the woofer, such as
the free-air resonance frequency and the compliance or
"springiness" of the suspension. Those can be gotten from
the supplier for most of the better brands, but they can
also be measured with fairly simple equipment. Then you
plug them into a formula that tells you the ideal box
volume.

Ported speakers have an additional variable. Instead of the
box being sealed, there is a "port" in it which is typically
tuned by having a heavy cardboard tube behind it. The
general idea is that the speaker and box combo has a
resonant frequency below which sound output falls off
quickly. The port can effectively move it down a bit. It
also increases bass output by radiating the lower
frequencies itself.

So back to your quest: You can do a full design job using
speaker parameters (or measurements) and equations (or
software), build a nice MDF box, and *then* cover it with
metal... or anything else. (Many people opt for fancy wood
veneer, but a cheap, simple, and attractive alternative is
upholstery fabric. It can be chosen to go with the room
decor (and easily changed later), and you can put it on with
a staple gun and some careful folding.)

Note that box design only pertains to the low-frequency
response of the woofer, but most speakers also have a
tweeter, or a tweeter and midrange (or multiple). The
tweeter/midrange needs to be matched to the upper end of the
woofer response, or (more typically) a "crossover" network
is used to low-pass filter the woofer and high-pass filter
the tweeter/midrange so the overall response is reasonably
flat. The crossover is thus an important comonent in the
overall system.

So the other way you can approach this is to buy a speaker
you like (actually a speaker system, including enclosure ,
woofer, tweeter, crossover, etc) and then cover it with
metal.

Or buy a kit from a supplier, which will typically have all
the parts (sometimes without the enclosure, just
construction plans). Follow their plans exactly and then
cover the enclosure with metal, OR come up with your own
enclosure design that has the exact same interior volume as
specified.

Best regards,


Bob Masta

DAQARTA v7.50
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusiq generator
Science with your sound card!

Thanks Bob and everyone else who replied nto my question. It seems
that making an enclosure that follows the speaker shape is a bad idea.
I suppose I could make some from wood lined metal but the shape will
still probably be wrong enough to make the speakers sound bad.
Eric

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

 

[Tim Wescott]

On Wed, 29 Jan 2014 09:10:53 -0800, etpm wrote:

On Wed, 29 Jan 2014 13:52:43 GMT, N0Spam@daqarta.com (Bob Masta)
wrote:

On Tue, 28 Jan 2014 13:51:06 -0800, etpm@whidbey.com wrote:

This speaker question kinda goes with my previous question(s) about
tubes. I have been looking at tube stuff on the web and some of it
really appeals to me. I'm a machinist and have a shop so making knobs
and the like is easy for me to do. And some of the tube sets with
exposed tubes and transformers sure are pretty. So I got to thinking
about speakers. I would like to have metal enclosures (cans really) for
the speakers that follow the shape of the speaker. Each speaker would
then be mounted on its own pole. Or maybe three speakers, mounted
vertically, on a pole. The enclosures would be nickel plated.
Probably brass, because I can spin brass. Nickel plate it too. I've got
the stuff. The enclsures should also have some sort of nickel plated
grille too. I know it sounds ridicolous, but the idea appeals to me.
Could I get good sound with the enclosures I'm describing? Would the
enclosure need to be perforated? Shoul I just get a life? Thanks,
Eric

Defintely do NOT make the enclosures from metal, or anything resonant.
The best material is actually one of the cheapest: Particle board.
Usually Medium Density Fiberboard (MDF) is recommended, but any flake
or chip composite will probably be OK. (High density is also good.)

As for your thought about following the shape of the speaker, the
enclosure shape is not terribly critical, but the volume is. There are
two basic design types: sealed box or ported box. (Omitting exotics
like horns and transmission lines.) In either case, the design box
volume is related to mechanical properties of the woofer, such as the
free-air resonance frequency and the compliance or "springiness" of the
suspension. Those can be gotten from the supplier for most of the
better brands, but they can also be measured with fairly simple
equipment. Then you plug them into a formula that tells you the ideal
box volume.

Ported speakers have an additional variable. Instead of the box being
sealed, there is a "port" in it which is typically tuned by having a
heavy cardboard tube behind it. The general idea is that the speaker
and box combo has a resonant frequency below which sound output falls
off quickly. The port can effectively move it down a bit. It also
increases bass output by radiating the lower frequencies itself.

So back to your quest: You can do a full design job using speaker
parameters (or measurements) and equations (or software), build a nice
MDF box, and *then* cover it with metal... or anything else. (Many
people opt for fancy wood veneer, but a cheap, simple, and attractive
alternative is upholstery fabric. It can be chosen to go with the room
decor (and easily changed later), and you can put it on with a staple
gun and some careful folding.)

Note that box design only pertains to the low-frequency response of the
woofer, but most speakers also have a tweeter, or a tweeter and midrange
(or multiple). The tweeter/midrange needs to be matched to the upper
end of the woofer response, or (more typically) a "crossover" network is
used to low-pass filter the woofer and high-pass filter the
tweeter/midrange so the overall response is reasonably flat. The
crossover is thus an important comonent in the overall system.

So the other way you can approach this is to buy a speaker you like
(actually a speaker system, including enclosure , woofer, tweeter,
crossover, etc) and then cover it with metal.

Or buy a kit from a supplier, which will typically have all the parts
(sometimes without the enclosure, just construction plans). Follow
their plans exactly and then cover the enclosure with metal, OR come up
with your own enclosure design that has the exact same interior volume
as specified.

Best regards,


Bob Masta

DAQARTA v7.50
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusiq generator
Science with your sound card!
Thanks Bob and everyone else who replied nto my question. It seems that
making an enclosure that follows the speaker shape is a bad idea.
I suppose I could make some from wood lined metal but the shape will
still probably be wrong enough to make the speakers sound bad.

You still seem to be missing the other half of the equation: the volume
of the enclosure will still be way too small.

Speakers need to be in BIG boxes, or they need some magic with the tuned
vents (the teeny Bose speakers have this magic).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Michael Black]

On Wed, 29 Jan 2014, etpm@whidbey.com wrote:

Thanks Bob and everyone else who replied nto my question. It seems
that making an enclosure that follows the speaker shape is a bad idea.
I suppose I could make some from wood lined metal but the shape will
still probably be wrong enough to make the speakers sound bad.
Eric

David Weems used to write endless construction articles for the hobby
electronic magazines on building speakers. And he'd use all kinds
of things, sewer pipes and cardboard boxes, to make the boxes. Just about
any shape or material did work. The caveat was that you had to know what
you were doing, understanding what the cabinet was there for and what made
one good and one bad.

It also matters what you are using the speakers for. Voice communication
has a very limited frequency range, and you can get by with a lot less. A
speaker running at low volume (because you've got it close to your ear)
will be less fussy than if you were running more power into it. If you
want hifi, you will need a lot more.

Headphones are easier to make "hifi" because they feed the ear directly,
thus low volume, but also the room doesn't become part of it all.
"Computer speakers" get away with being really awful because one generally
has them relatively close to the ears. One might be better off mounting
them on your chair, feeding the ears more directly.

Michael

 

[Tim Wescott]

On Wed, 29 Jan 2014 14:32:43 -0500, Michael Black wrote:

On Wed, 29 Jan 2014, etpm@whidbey.com wrote:



Thanks Bob and everyone else who replied nto my question. It seems that
making an enclosure that follows the speaker shape is a bad idea.
I suppose I could make some from wood lined metal but the shape will
still probably be wrong enough to make the speakers sound bad.
Eric

David Weems used to write endless construction articles for the hobby
electronic magazines on building speakers. And he'd use all kinds of
things, sewer pipes and cardboard boxes, to make the boxes. Just about
any shape or material did work. The caveat was that you had to know
what you were doing, understanding what the cabinet was there for and
what made one good and one bad.

It also matters what you are using the speakers for. Voice
communication has a very limited frequency range, and you can get by
with a lot less. A speaker running at low volume (because you've got it
close to your ear) will be less fussy than if you were running more
power into it. If you want hifi, you will need a lot more.

Headphones are easier to make "hifi" because they feed the ear directly,
thus low volume, but also the room doesn't become part of it all.
"Computer speakers" get away with being really awful because one
generally has them relatively close to the ears. One might be better
off mounting them on your chair, feeding the ears more directly.

Soon, upscale hospitals in high-tech centers will be offering Bluetooth
neural implants for infants, side-stepping this whole messy vibrate-the-
air business.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[George Herold]

On Tuesday, January 28, 2014 4:51:06 PM UTC-5, et...@whidbey.com wrote:

This speaker question kinda goes with my previous question(s) abou
tubes. I have been looking at tube stuff on the web and some of it
really appeals to me. I'm a machinist and have a shop so making knobs
and the like is easy for me to do. And some of the tube sets with
exposed tubes and transformers sure are pretty. So I got to thinking
about speakers. I would like to have metal enclosures (cans really)
for the speakers that follow the shape of the speaker. Each speaker
would then be mounted on its own pole. Or maybe three speakers,
mounted vertically, on a pole. The enclosures would be nickel plated.
Probably brass, because I can spin brass. Nickel plate it too. I've
got the stuff. The enclsures should also have some sort of nickel
plated grille too. I know it sounds ridicolous, but the idea appeal

Hi Eric, OK this is a total hijack of your thread and question.
(I suppose I should take it over to rec.crafts.metalworking... but you know what it's like over there.)
So can I ask a few questions about metal spinning?
I'd like to make some little radiation shields for use at 77K (liquid nitrogen)
So cylindrical type cups.. maybe 2" diameter and ~4" long. I've only heard about spinning aluminum, but you mentioned brass. Can you also spin something like TeCu (tellurium copper)

Does the spinning work harden the metal?
Can it be annealed afterwords?
How thin a wall/ bottom can you get.

Thanks.
George H.
gherold(-AT-)teachspin.com

to me. Could I get good sound with the enclosures I'm describing?

Would the enclosure need to be perforated? Shoul I just get a life?

Thanks,

Eric



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[RobertMacy]

On Wed, 29 Jan 2014 10:10:53 -0700, <etpm@whidbey.com> wrote:

...snip....
Thanks Bob and everyone else who replied nto my question. It seems
that making an enclosure that follows the speaker shape is a bad idea.
I suppose I could make some from wood lined metal but the shape will
still probably be wrong enough to make the speakers sound bad.
Eric

I have heard that 'stone' works well. The mass helps provide a stable
platform. A few years ago I saw an article on using the clay tile
drainpipe as a stand for mounting speakers inside it. The idea was that
the back side being open provided a phase boost to the bass and took the
low end lower than the speaker, or so.

Sorry, years ago, can't recall the publication, nor name of article.

 

[Michael Black]

On Thu, 30 Jan 2014, RobertMacy wrote:

On Wed, 29 Jan 2014 10:10:53 -0700, <etpm@whidbey.com> wrote:

...snip....
Thanks Bob and everyone else who replied nto my question. It seems
that making an enclosure that follows the speaker shape is a bad idea.
I suppose I could make some from wood lined metal but the shape will
still probably be wrong enough to make the speakers sound bad.
Eric

I have heard that 'stone' works well. The mass helps provide a stable
platform. A few years ago I saw an article on using the clay tile drainpipe
as a stand for mounting speakers inside it. The idea was that the back side
being open provided a phase boost to the bass and took the low end lower than
the speaker, or so.

I suspect there were some commercial speakers made with stone or concrete.

But that's the advantage of making your own, you can try things that
aren't economically feasible. Stone or cement might be cheaper than some
other materials, but the cost of shipping is going to ruin it. But if you
can get locally, you can experiment.


> Sorry, years ago, can't recall the publication, nor name of article.

Probably Popular Electronics, that often had a speaker project in an
issue, and as I previously said, often written by David Weems.

I certainly remember one article by him about using a drainpipe.

Michael

 

[RobertMacy]

On Thu, 30 Jan 2014 09:01:54 -0700, Michael Black <et472@ncf.ca> wrote:

...snip...
Probably Popular Electronics, that often had a speaker project in an
issue, and as I previously said, often written by David Weems.

I certainly remember one article by him about using a drainpipe.

Michael

Bet that's it!

Plus, remember someone made a rack of sixteen, mounted four by four, 4
inch speakers that made a woofer like you wouldn't believe. Then, someone
complained about all the resonances adding up or such. sigh. you can spend
a lifetime in this and NEVER make much progress.

 

[Tim Wescott]

On Thu, 30 Jan 2014 06:52:00 -0800, George Herold wrote:

On Tuesday, January 28, 2014 4:51:06 PM UTC-5, et...@whidbey.com wrote:
This speaker question kinda goes with my previous question(s) abou
tubes. I have been looking at tube stuff on the web and some of it
really appeals to me. I'm a machinist and have a shop so making knobs
and the like is easy for me to do. And some of the tube sets with
exposed tubes and transformers sure are pretty. So I got to thinking
about speakers. I would like to have metal enclosures (cans really)
for the speakers that follow the shape of the speaker. Each speaker
would then be mounted on its own pole. Or maybe three speakers,
mounted vertically, on a pole. The enclosures would be nickel plated.
Probably brass, because I can spin brass. Nickel plate it too. I've got
the stuff. The enclsures should also have some sort of nickel plated
grille too. I know it sounds ridicolous, but the idea appeal

Hi Eric, OK this is a total hijack of your thread and question.
(I suppose I should take it over to rec.crafts.metalworking... but you
know what it's like over there.)
So can I ask a few questions about metal spinning?
I'd like to make some little radiation shields for use at 77K (liquid
nitrogen)
So cylindrical type cups.. maybe 2" diameter and ~4" long. I've only
heard about spinning aluminum, but you mentioned brass. Can you also
spin something like TeCu (tellurium copper)

Does the spinning work harden the metal?
Can it be annealed afterwords?
How thin a wall/ bottom can you get.

Please please please ask this question on the metalworking group.

Here's the answers to your questions, to the best of my knowledge:

Yes.

Yes, depending on the alloy.

Dunno, but probably way thin.

I used to work at an infra red imaging company that needed pretty fancy
little radiation shields to get adequate image quality. They were made
by machining an aluminum mandrel on a lathe, then plating it with copper,
then etching away the aluminum in an acid chosen to dissolve aluminum but
not Cu.

It worked a treat, but the whole system cost $$$$$, so it's not
necessarily cheap.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Michael Black]

On Thu, 30 Jan 2014, RobertMacy wrote:

On Thu, 30 Jan 2014 09:01:54 -0700, Michael Black <et472@ncf.ca> wrote:

...snip...
Probably Popular Electronics, that often had a speaker project in an issue,
and as I previously said, often written by David Weems.

I certainly remember one article by him about using a drainpipe.

Michael


Bet that's it!

Plus, remember someone made a rack of sixteen, mounted four by four, 4 inch
speakers that made a woofer like you wouldn't believe. Then, someone
complained about all the resonances adding up or such. sigh. you can spend a
lifetime in this and NEVER make much progress.

Jim Kyle had that article about the "Sweet 16", yes lots of speakers and
something about how the multiple speakers null out the bad parts of the
cheap speakers or something like that.

I thought it was just a general speaker, not a woofer, but the accumulated
speakers allowed for bass response.

It was in Popular Electronics in the late fifties or early sixties, I've
seen the article, it's somewhere around here (and might be on the
internet). And for the next decade, there were followup articles, some
arguing against, some in favor, and others extending the idea. I think
there were even commercial versions of it, but there may have been more
planning to those while a review I think I read saw it only as a commecial
version of the Sweet 16.

Michael

 

On Thu, 30 Jan 2014 06:52:00 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

On Tuesday, January 28, 2014 4:51:06 PM UTC-5, et...@whidbey.com wrote:
This speaker question kinda goes with my previous question(s) abou
tubes. I have been looking at tube stuff on the web and some of it
really appeals to me. I'm a machinist and have a shop so making knobs
and the like is easy for me to do. And some of the tube sets with
exposed tubes and transformers sure are pretty. So I got to thinking
about speakers. I would like to have metal enclosures (cans really)
for the speakers that follow the shape of the speaker. Each speaker
would then be mounted on its own pole. Or maybe three speakers,
mounted vertically, on a pole. The enclosures would be nickel plated.
Probably brass, because I can spin brass. Nickel plate it too. I've
got the stuff. The enclsures should also have some sort of nickel
plated grille too. I know it sounds ridicolous, but the idea appeal

Hi Eric, OK this is a total hijack of your thread and question.
(I suppose I should take it over to rec.crafts.metalworking... but you know what it's like over there.)
So can I ask a few questions about metal spinning?
I'd like to make some little radiation shields for use at 77K (liquid nitrogen)
So cylindrical type cups.. maybe 2" diameter and ~4" long. I've only heard about spinning aluminum, but you mentioned brass. Can you also spin something like TeCu (tellurium copper)

Does the spinning work harden the metal?
Can it be annealed afterwords?
How thin a wall/ bottom can you get.

Thanks.
George H.
gherold(-AT-)teachspin.com

Greetings George,
You can indeed spin many different metals. I have never worked with
tellurium copper alloy and so can't say whether it can be spun easily.
Spinning does work harden the metal. Depending on the amount of
movement from the original disc a part may or may not need annealing.
Cylindrical cups are hard to spin. especially the ones you describe.
You would be better off soldering or welding. Can TeCu be welded? Will
the fumes kill you? One of the first things I attempted to spin was a
sterling silver shot glass. Tall for its diameter. It was quite a
challenge.
Eric

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