Adding filter to a INA217...

[John Walliker]

On Sunday, 20 February 2022 at 22:05:02 UTC, amdx wrote:

On 2/20/2022 3:40 PM, Rick C wrote:
On Sunday, February 20, 2022 at 3:06:25 PM UTC-5, amdx wrote:
On 2/20/2022 12:43 PM, Rick C wrote:
On Sunday, February 20, 2022 at 9:53:45 AM UTC-5, amdx wrote:
If that happens I may need a sharper filter. I need a first iteration
and adjust from there.

Not measuring, just want to listen to the drug deals across the street.

And then what ever else. May need to be able to switch filters in and
out at some point

to make it more versatile.
If you really want to listen to drug deals, the parabolic reflector is what you want. It doesn\'t even need to be large.
An old satellite dish would do a decent job and be more inconspicuous than a typical reflector microphone.
Yes, I\'m kicking myself, I had 3 of them and in a recent clean up, I
threw the all out. I\'m now looking for another one.
Just mount your preamp amp next to the electret mic. I second the idea of ditching the differential amp, but there\'s really nothing wrong with it other than being hard to modify. A single, simple op amp can be the preamp next to the mic and provide your low pass and high pass filtering with one pole each. The main concern on the preamp is to not overload the preamp. Then you can add more filtering on the main amp to prevent that amp from overloading if needed.

Here is an interesting preamp candidate with compression.

file:///C:/Users/Rick/AppData/Local/Temp/ssm2167.pdf
Yes, I ordered a cornucopia of mic amps! I have on hand PCBs with the
SSM2167, TS472 and the INA217, and then a Headphone driver amp
https://www.ebay.com/itm/143774994752

About $8 from ebay. You can adjust C1 or C2 for the high pass filter and add a low pass filter between the mic and the amp.

The compression will help to hear quiet sounds without louder sounds overloading the amps.

That Ebay PCB is the one I have.
So what is wrong with that circuit?


Yes, I liked the idea of compression, I had a few issues with loud sound
on my ears using the Gain of 3,500 amp I built first.

Here\'s the 3,500 Voltage gain amp.

https://sound-au.com/project13.htm
Anything I do now, is to compare to that amp.
If the only problem is too much gain, adjust the gain to something lower.


Although, I now have the headphone amp which has a gain of 4 too add
after the preamps.

Just need to do something
That doesn\'t narrow the field much. What problems are you having that you need to solve? Which circuit are you using? Which circuit do you want to use?

The only thing I\'m doing noise is to see if I get less noise with in
other preamp. Just more experimentation than anything.

I see Phil is still posting, has he said anything good that you want
to pass along. I\'m not reading his posts.
Mikek


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

That amplifier does NOT have a gain of 3500. That figure is its open-loop gain
before negative feedback.

There is no need to buy a special pcb for this. The circuits you need are so
simple that you could easily wire them up in \"dead bug\" mode on a scrap of
copper clad FR4 laminate. Any reasonable pre-amp circuit intended for use
with an electret microphone will give you good performance. The mic you are
using gives a high output already compared with many alternatives.

High-pass filtering at the INPUT to the pre-amp at maybe 100 to 300 Hz will be
useful to stop the pre-amp from overloading on wind noise.
Quite apart from the electronics, I do think that pointing something that looks
like a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.
John

 

[Phil Allison]

John Walliker wrote:
================

Quite apart from the electronics, I do think that pointing something that looks
like a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.

** Go ahead Mikek - make my day .....



....... Phil

 

[Phil Allison]

John Walliker wrote:
=================

The OP is already using a high-sensitivity electret mic. The AOM5024 has a
sensitivity of -24dBV/Pa when used with a 3V supply and 2.2k resistor. The noise
floor is 14dB(A) spl which is very good.

This mic is one of the best in its class
and its cheap and readily available. It is VERY hard to find an outdoors environment
which is as quiet as 14dB(A), so the noise performance of this mic is good enough.

** That 14 dBA spl figure seems fake.

This seems to be the same capsule:

https://cdn-shop.adafruit.com/datasheets/CMA-4544PF-W.pdf

The sellers claim -60dB rel to 1 Pa = 94dB A spl.
So the self noise is equal to 34 dB A spl.

Which seems about right for a 10mm dia, $1.50 electret capsule.
This might explain the nutty OP\'s issue.



...... Phil

 

[amdx]

On 2/20/2022 5:31 PM, John Walliker wrote:

On Sunday, 20 February 2022 at 22:05:02 UTC, amdx wrote:
On 2/20/2022 3:40 PM, Rick C wrote:
On Sunday, February 20, 2022 at 3:06:25 PM UTC-5, amdx wrote:
On 2/20/2022 12:43 PM, Rick C wrote:
On Sunday, February 20, 2022 at 9:53:45 AM UTC-5, amdx wrote:
If that happens I may need a sharper filter. I need a first iteration
and adjust from there.

Not measuring, just want to listen to the drug deals across the street.

And then what ever else. May need to be able to switch filters in and
out at some point

to make it more versatile.
If you really want to listen to drug deals, the parabolic reflector is what you want. It doesn\'t even need to be large.
An old satellite dish would do a decent job and be more inconspicuous than a typical reflector microphone.
Yes, I\'m kicking myself, I had 3 of them and in a recent clean up, I
threw the all out. I\'m now looking for another one.
Just mount your preamp amp next to the electret mic. I second the idea of ditching the differential amp, but there\'s really nothing wrong with it other than being hard to modify. A single, simple op amp can be the preamp next to the mic and provide your low pass and high pass filtering with one pole each. The main concern on the preamp is to not overload the preamp. Then you can add more filtering on the main amp to prevent that amp from overloading if needed.

Here is an interesting preamp candidate with compression.

file:///C:/Users/Rick/AppData/Local/Temp/ssm2167.pdf
Yes, I ordered a cornucopia of mic amps! I have on hand PCBs with the
SSM2167, TS472 and the INA217, and then a Headphone driver amp
https://www.ebay.com/itm/143774994752

About $8 from ebay. You can adjust C1 or C2 for the high pass filter and add a low pass filter between the mic and the amp.

The compression will help to hear quiet sounds without louder sounds overloading the amps.

That Ebay PCB is the one I have.
So what is wrong with that circuit?


Yes, I liked the idea of compression, I had a few issues with loud sound
on my ears using the Gain of 3,500 amp I built first.

Here\'s the 3,500 Voltage gain amp.

https://sound-au.com/project13.htm
Anything I do now, is to compare to that amp.
If the only problem is too much gain, adjust the gain to something lower.


Although, I now have the headphone amp which has a gain of 4 too add
after the preamps.

Just need to do something
That doesn\'t narrow the field much. What problems are you having that you need to solve? Which circuit are you using? Which circuit do you want to use?

The only thing I\'m doing noise is to see if I get less noise with in
other preamp. Just more experimentation than anything.

I see Phil is still posting, has he said anything good that you want
to pass along. I\'m not reading his posts.
Mikek


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
That amplifier does NOT have a gain of 3500. That figure is its open-loop gain
before negative feedback.

 I measured it. You\'re right I I exaggerated a bit, it was 3,400 plus ,
driving 64Ω headphones.

There is no need to buy a special pcb for this. The circuits you need are so
simple that you could easily wire them up in \"dead bug\" mode on a scrap of
copper clad FR4 laminate. Any reasonable pre-amp circuit intended for use
with an electret microphone will give you good performance. The mic you are
using gives a high output already compared with many alternatives.

 $3.75 for the TS472 Populated PCB and $4.75 for the populated SSM2167
PCB includes the shipping.

 Can\'t do much better than those prices.

 The INA217 PCB was more expensive for an unpopulated PCB at $15 with
shipping, I was swayed by the low noise

nomenclature.

High-pass filtering at the INPUT to the pre-amp at maybe 100 to 300 Hz will be
useful to stop the pre-amp from overloading on wind noise.
Quite apart from the electronics, I do think that pointing something that looks
like a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.
John

 Maybe it should be loaded. The police have no interest anymore, as
they don\'t deal anymore! But the guy that

delivers twice a week is dealing. He has a handicap plate, I guess he is
just supplementing his disability check.

They don\'t hide it, a little chit chat, the money transfer, a little
more chit chat and drug hand off and he\'s off to the next delivery.

Two women have died of ODs and one died of a brain hemorrhage after
getting a beating, spent over a week in

a coma and more time in the hospital. Came right back home to the
abusive situation and died from the hemorrhage

about 3 weeks later. No one went to jail for any of this. The fire
truck, and ambulances have showed up more than

10 times for ODs. The cops dozens of times. After the narcan, they
usually refuse to go with the ambulance.

The coroner has showed up twice, took away a white zippered bag on the
gurney.

Just 3 houses in my subdivision of about 97 homes are a problem.

 I happen to have one next door and another across the street. It\'s a
Soap Opera.

 Sometime I\'ll tell you about the other neighbors, young lady passing
out at a stoplight with here six month old in the car,

a gun in her purse and opioids. But that\'s another story to go with the
50 gram bust.

                                   Mikek

 

[Rick C]

On Sunday, February 20, 2022 at 5:05:02 PM UTC-5, amdx wrote:

On 2/20/2022 3:40 PM, Rick C wrote:
On Sunday, February 20, 2022 at 3:06:25 PM UTC-5, amdx wrote:
On 2/20/2022 12:43 PM, Rick C wrote:
On Sunday, February 20, 2022 at 9:53:45 AM UTC-5, amdx wrote:
If that happens I may need a sharper filter. I need a first iteration
and adjust from there.

Not measuring, just want to listen to the drug deals across the street.

And then what ever else. May need to be able to switch filters in and
out at some point

to make it more versatile.
If you really want to listen to drug deals, the parabolic reflector is what you want. It doesn\'t even need to be large.
An old satellite dish would do a decent job and be more inconspicuous than a typical reflector microphone.
Yes, I\'m kicking myself, I had 3 of them and in a recent clean up, I
threw the all out. I\'m now looking for another one.
Just mount your preamp amp next to the electret mic. I second the idea of ditching the differential amp, but there\'s really nothing wrong with it other than being hard to modify. A single, simple op amp can be the preamp next to the mic and provide your low pass and high pass filtering with one pole each. The main concern on the preamp is to not overload the preamp. Then you can add more filtering on the main amp to prevent that amp from overloading if needed.

Here is an interesting preamp candidate with compression.

file:///C:/Users/Rick/AppData/Local/Temp/ssm2167.pdf
Yes, I ordered a cornucopia of mic amps! I have on hand PCBs with the
SSM2167, TS472 and the INA217, and then a Headphone driver amp
https://www.ebay.com/itm/143774994752

About $8 from ebay. You can adjust C1 or C2 for the high pass filter and add a low pass filter between the mic and the amp.

The compression will help to hear quiet sounds without louder sounds overloading the amps.

That Ebay PCB is the one I have.
So what is wrong with that circuit?


Yes, I liked the idea of compression, I had a few issues with loud sound
on my ears using the Gain of 3,500 amp I built first.

Here\'s the 3,500 Voltage gain amp.

https://sound-au.com/project13.htm
Anything I do now, is to compare to that amp.
If the only problem is too much gain, adjust the gain to something lower.


Although, I now have the headphone amp which has a gain of 4 too add
after the preamps.

Just need to do something
That doesn\'t narrow the field much. What problems are you having that you need to solve? Which circuit are you using? Which circuit do you want to use?

The only thing I\'m doing noise is to see if I get less noise with in
other preamp. Just more experimentation than anything.

I see Phil is still posting, has he said anything good that you want
to pass along. I\'m not reading his posts.

I don\'t really read his posts either. Once he gets into IP (Insane Phil) mode, he usually doesn\'t return. He just wanders around the lamp post mumbling and ranting a bit. It\'s a shame really. I get the sense that somewhere in there is a decent guy. He just can\'t handle anything remotely like criticism or I don\'t know what really. He just goes off at the slightest provocation. Kinda like old dynamite.

I don\'t think you are going to see much improvement from your filtering, but give it a try and see what happens. You can try running some tests. Try using your PC to do a frequency sweep before and after. That will verify your corner frequencies. Parasitic elements can change the actual results.

--

Rick C.

-++ Get 1,000 miles of free Supercharging
-++ Tesla referral code - https://ts.la/richard11209

 

[Jan Panteltje]

On a sunny day (Sun, 20 Feb 2022 15:31:02 -0800 (PST)) it happened John
Walliker <jrwalliker@gmail.com> wrote in
<153b314d-6fb5-497a-8c8a-76d978f18a08n@googlegroups.com>:

a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.
John

Having lived in Amsterdam the way to find out what they are saying is go over there
and say \"hey man I am buying, what you have for me?\"
;-)

 

[John Walliker]

On Monday, 21 February 2022 at 00:10:53 UTC, palli...@gmail.com wrote:

John Walliker wrote:
=================

The OP is already using a high-sensitivity electret mic. The AOM5024 has a
sensitivity of -24dBV/Pa when used with a 3V supply and 2.2k resistor. The noise
floor is 14dB(A) spl which is very good.

This mic is one of the best in its class
and its cheap and readily available. It is VERY hard to find an outdoors environment
which is as quiet as 14dB(A), so the noise performance of this mic is good enough.


** That 14 dBA spl figure seems fake.

This seems to be the same capsule:

https://cdn-shop.adafruit.com/datasheets/CMA-4544PF-W.pdf

The sellers claim -60dB rel to 1 Pa = 94dB A spl.
So the self noise is equal to 34 dB A spl.

Which seems about right for a 10mm dia, $1.50 electret capsule.
This might explain the nutty OP\'s issue.

..... Phil

The mic you linked to is from a different manufacturer with a
similar name, although such products are sometimes rebadged.
PUI do make very specific claims about the noise performance so I
would be surprised if they were significantly exaggerated. I have used
quite a lot of the AOM-5024 mics and have found them to be very
good. I will check the noise floor some time when I have the
right equipment set up.

John

 

[Phil Allison]

On Monday, February 21, 2022 at 7:40:33 PM UTC+11, John Walliker wrote:

On Monday, 21 February 2022 at 00:10:53 UTC, palli...@gmail.com wrote:
John Walliker wrote:
=================

The OP is already using a high-sensitivity electret mic. The AOM5024 has a
sensitivity of -24dBV/Pa when used with a 3V supply and 2.2k resistor. The noise
floor is 14dB(A) spl which is very good.

This mic is one of the best in its class
and its cheap and readily available. It is VERY hard to find an outdoors environment
which is as quiet as 14dB(A), so the noise performance of this mic is good enough.


** That 14 dBA spl figure seems fake.

This seems to be the same capsule:

https://cdn-shop.adafruit.com/datasheets/CMA-4544PF-W.pdf

The sellers claim -60dB rel to 1 Pa = 94dB A spl.
So the self noise is equal to 34 dB A spl.

Which seems about right for a 10mm dia, $1.50 electret capsule.
This might explain the nutty OP\'s issue.

..... Phil

The mic you linked to is from a different manufacturer with a
similar name, although such products are sometimes rebadged.

** You bet.

PUI do make very specific claims about the noise performance so I
would be surprised if they were significantly exaggerated.

** Been dealing with mics, dynamic, true condenser and electrets for over 50 years.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
25 to 30 dB or so equivalent SPL is the norm.
A 10mm dia one one is half the size of any of the above.

FYI: there are two very reliable ways to test the self noise of a mic that has a pre-amp built in.

1. Place it in a silent chamber - a heavy cast iron sphere with a good air seal sited in a quiet room.

2. Place it in a vacuum.





...... Phil

 

[John Walliker]

On Monday, 21 February 2022 at 09:12:48 UTC, palli...@gmail.com wrote:

On Monday, February 21, 2022 at 7:40:33 PM UTC+11, John Walliker wrote:
On Monday, 21 February 2022 at 00:10:53 UTC, palli...@gmail.com wrote:
John Walliker wrote:
=================

The OP is already using a high-sensitivity electret mic. The AOM5024 has a
sensitivity of -24dBV/Pa when used with a 3V supply and 2.2k resistor. The noise
floor is 14dB(A) spl which is very good.

This mic is one of the best in its class
and its cheap and readily available. It is VERY hard to find an outdoors environment
which is as quiet as 14dB(A), so the noise performance of this mic is good enough.


** That 14 dBA spl figure seems fake.

This seems to be the same capsule:

https://cdn-shop.adafruit.com/datasheets/CMA-4544PF-W.pdf

The sellers claim -60dB rel to 1 Pa = 94dB A spl.
So the self noise is equal to 34 dB A spl.

Which seems about right for a 10mm dia, $1.50 electret capsule.
This might explain the nutty OP\'s issue.

..... Phil

The mic you linked to is from a different manufacturer with a
similar name, although such products are sometimes rebadged.
** You bet.
PUI do make very specific claims about the noise performance so I
would be surprised if they were significantly exaggerated.
** Been dealing with mics, dynamic, true condenser and electrets for over 50 years.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
25 to 30 dB or so equivalent SPL is the norm.
A 10mm dia one one is half the size of any of the above.

FYI: there are two very reliable ways to test the self noise of a mic that has a pre-amp built in.

1. Place it in a silent chamber - a heavy cast iron sphere with a good air seal sited in a quiet room.

2. Place it in a vacuum.

When I visited the UK Knowles factory before they moved it to the far east I
was shown the test rig they used for measuring microphone noise.
It was a large block of steel, about 30cm on each side with a cavity inside.
The lid was a thick steel plate which could slide over the top of the cavity
to give access. The whole thing was supported on air-filled rubber tubes.
Using a vacuum would give an artificially low noise level as there would
be no brownian movement of air molecules. According to Knowles,
about half the noise of a good electret mic comes from the FET and about
half comes from brownian motion of the air molecules.
There are other 10mm electret capsules that claim a similar noise level,
for example the Primo EM272 and EM273.

John

 

[Phil Allison]

John Walliker wrote:
---------------------------------

** Been dealing with mics, dynamic, true condenser and electrets for over 50 years.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
25 to 30 dB or so equivalent SPL is the norm.
A 10mm dia one one is half the size of any of the above.

FYI: there are two very reliable ways to test the self noise of a mic that has a pre-amp built in.

1. Place it in a silent chamber - a heavy cast iron sphere with a good air seal sited in a quiet room.

2. Place it in a vacuum.

When I visited the UK Knowles factory

** They make tiny hearing aid mics - right?
Very different game.

Using a vacuum would give an artificially low noise level as there would
be no brownian movement of air molecules.

** Nonsense - no mic made for audio gets anywhere near that level.

According to Knowles,
about half the noise of a good electret mic comes from the FET and about
half comes from brownian motion of the air molecules.

** Totally false.

A vacuum eliminates all sound transmission to the diaphragm - so is a fair test.

There are other 10mm electret capsules that claim a similar noise level,
for example the Primo EM272 and EM273.

** FYI

Condenser mic self noise is mostly low frequency, unlike that from dynamic mics which is close to white noise - rising 6dB with each octave.
As a result, the \"A\" weighting curve has a much bigger effect on condenser models than dynamics.
There are some games being played here with specs.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
Look a few up.


...... Phil

 

[bitrex]

On 2/20/2022 3:08 PM, Phil Allison wrote:

amdx wrote:
===========

Not measuring, just want to listen to the drug deals across the street.


** Monitoring private conversations is ILLEGAL !!

Both fines an jail time are penalties.
So you go right ahead - asshole.

...... Phil

If he lives in a \"one-party\" state in the US he can use an audio
enhancement device to monitor a private oral conversation, so long as at
least one party participating is aware.

So if he lives in one of those he\'ll have to go buy some drugs I guess.
He should probably try not to get caught at it though as a buyer wearing
a wire likely makes drug dealers pretty unhappy

 

[Phil Allison]

bitrex is a cunthead wrote:

==================

amdx wrote:
===========

Not measuring, just want to listen to the drug deals across the street.


** Monitoring private conversations is ILLEGAL !!

Both fines an jail time are penalties.
So you go right ahead - asshole.

If he lives in a \"one-party\" state in the US he can use an audio
enhancement device to monitor a private oral conversation, so long as at
least one party participating is aware.

** Nothing to do with what I said above.

The OP wants to remotely monitor a private conversation.
Illegal anywhere.

FOAD you bullshitting POS.


....... Phil

 

[bitrex]

On 2/21/2022 4:35 PM, Phil Allison wrote:

bitrex is a cunthead wrote:

==================
amdx wrote:
===========

Not measuring, just want to listen to the drug deals across the street.


** Monitoring private conversations is ILLEGAL !!

Both fines an jail time are penalties.
So you go right ahead - asshole.

If he lives in a \"one-party\" state in the US he can use an audio
enhancement device to monitor a private oral conversation, so long as at
least one party participating is aware.

** Nothing to do with what I said above.

The OP wants to remotely monitor a private conversation.
Illegal anywhere.

FOAD you bullshitting POS.


...... Phil

Phil\'s not quite as unhappy as a drug dealer would be if he caught amdx
wearing a wire but we\'re getting warmer.

 

[bitrex]

On 2/20/2022 7:27 PM, amdx wrote:

On 2/20/2022 5:31 PM, John Walliker wrote:
On Sunday, 20 February 2022 at 22:05:02 UTC, amdx wrote:
On 2/20/2022 3:40 PM, Rick C wrote:
On Sunday, February 20, 2022 at 3:06:25 PM UTC-5, amdx wrote:
On 2/20/2022 12:43 PM, Rick C wrote:
On Sunday, February 20, 2022 at 9:53:45 AM UTC-5, amdx wrote:
If that happens I may need a sharper filter. I need a first
iteration
and adjust from there.

Not measuring, just want to listen to the drug deals across the
street.

And then what ever else. May need to be able to switch filters in
and
out at some point

to make it more versatile.
If you really want to listen to drug deals, the parabolic
reflector is what you want. It doesn\'t even need to be large.
An old satellite dish would do a decent job and be more
inconspicuous than a typical reflector microphone.
Yes, I\'m kicking myself, I had 3 of them and in a recent clean up, I
threw the all out. I\'m now looking for another one.
Just mount your preamp amp next to the electret mic. I second the
idea of ditching the differential amp, but there\'s really nothing
wrong with it other than being hard to modify. A single, simple op
amp can be the preamp next to the mic and provide your low pass
and high pass filtering with one pole each. The main concern on
the preamp is to not overload the preamp. Then you can add more
filtering on the main amp to prevent that amp from overloading if
needed.

Here is an interesting preamp candidate with compression.

file:///C:/Users/Rick/AppData/Local/Temp/ssm2167.pdf
Yes, I ordered a cornucopia of mic amps! I have on hand PCBs with the
SSM2167, TS472 and the INA217, and then a Headphone driver amp
https://www.ebay.com/itm/143774994752

About $8 from ebay. You can adjust C1 or C2 for the high pass
filter and add a low pass filter between the mic and the amp.

The compression will help to hear quiet sounds without louder
sounds overloading the amps.

That Ebay PCB is the one I have.
So what is wrong with that circuit?


Yes, I liked the idea of compression, I had a few issues with loud
sound
on my ears using the Gain of 3,500 amp I built first.

Here\'s the 3,500 Voltage gain amp.

https://sound-au.com/project13.htm
Anything I do now, is to compare to that amp.
If the only problem is too much gain, adjust the gain to something
lower.


Although, I now have the headphone amp which has a gain of 4 too add
after the preamps.

Just need to do something
That doesn\'t narrow the field much. What problems are you having
that you need to solve? Which circuit are you using? Which circuit
do you want to use?

The only thing I\'m doing noise is to see if I get less noise with in
other preamp. Just more experimentation than anything.

  I see Phil is still posting, has he said anything good that you want
to pass along. I\'m not reading his posts.
Mikek


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
That amplifier does NOT have a gain of 3500.  That figure is its
open-loop gain
before negative feedback.
 I measured it. You\'re right I I exaggerated a bit, it was 3,400 plus ,
driving 64Ω headphones.

There is no need to buy a special pcb for this.  The circuits you need
are so
simple that you could easily wire them up in \"dead bug\" mode on a
scrap of
copper clad FR4 laminate.  Any reasonable pre-amp circuit intended for
use
with an electret microphone will give you good performance.  The mic
you are
using gives a high output already compared with many alternatives.

 $3.75 for the TS472 Populated PCB and $4.75 for the populated SSM2167
PCB includes the shipping.

 Can\'t do much better than those prices.

 The INA217 PCB was more expensive for an unpopulated PCB at $15 with
shipping, I was swayed by the low noise

nomenclature.



High-pass filtering at the INPUT to the pre-amp at maybe 100 to 300 Hz
will be
useful to stop the pre-amp from overloading on wind noise.
Quite apart from the electronics, I do think that pointing something
that looks
like a Gatling gun towards people you think might be drug dealers is
maybe
a little unwise.
John

 Maybe it should be loaded. The police have no interest anymore, as
they don\'t deal anymore! But the guy that

delivers twice a week is dealing. He has a handicap plate, I guess he is
just supplementing his disability check.

They don\'t hide it, a little chit chat, the money transfer, a little
more chit chat and drug hand off and he\'s off to the next delivery.

Probably best to be confident it\'s not just the Uber Eats deliveryman
you have \"apprehended\", here. Did they hand them a large bag? Like a bag
that had the name of a Chinese restaurant on the side?

 

[bitrex]

On 2/21/2022 1:04 AM, Jan Panteltje wrote:

On a sunny day (Sun, 20 Feb 2022 15:31:02 -0800 (PST)) it happened John
Walliker <jrwalliker@gmail.com> wrote in
153b314d-6fb5-497a-8c8a-76d978f18a08n@googlegroups.com>:


a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.
John

Having lived in Amsterdam the way to find out what they are saying is go over there
and say \"hey man I am buying, what you have for me?\"
;-)

Drug dealers making house calls seems a little unusual unless you have
serious money on offer, or they\'re just small-timers peddling small-time
weed to their friends, in the US it sounds like a good way to get
robbed/killed. Everyone is armed and you have no idea what you\'re
walking into.

In the \'hood at least historically they tend to stick to their \"turf\"
and buyers come to them. But maybe the pandemic has changed even that

 

[Lasse Langwadt Christensen]

mandag den 21. februar 2022 kl. 23.19.27 UTC+1 skrev bitrex:

On 2/21/2022 1:04 AM, Jan Panteltje wrote:
On a sunny day (Sun, 20 Feb 2022 15:31:02 -0800 (PST)) it happened John
Walliker <jrwal...@gmail.com> wrote in
153b314d-6fb5-497a...@googlegroups.com>:


a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.
John

Having lived in Amsterdam the way to find out what they are saying is go over there
and say \"hey man I am buying, what you have for me?\"
;-)

Drug dealers making house calls seems a little unusual unless you have
serious money on offer, or they\'re just small-timers peddling small-time
weed to their friends, in the US it sounds like a good way to get
robbed/killed. Everyone is armed and you have no idea what you\'re
walking into.

In the \'hood at least historically they tend to stick to their \"turf\"
and buyers come to them. But maybe the pandemic has changed even that

here has been a few cases of so called \"white delivery\".
order via snapchat or SMS, and cocain, estacy or similar will be be delivered
to your door, just like a pizza.

if there is a market someone will make a business out of it...

 

[bitrex]

On 2/21/2022 5:47 PM, Lasse Langwadt Christensen wrote:

mandag den 21. februar 2022 kl. 23.19.27 UTC+1 skrev bitrex:
On 2/21/2022 1:04 AM, Jan Panteltje wrote:
On a sunny day (Sun, 20 Feb 2022 15:31:02 -0800 (PST)) it happened John
Walliker <jrwal...@gmail.com> wrote in
153b314d-6fb5-497a...@googlegroups.com>:


a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.
John

Having lived in Amsterdam the way to find out what they are saying is go over there
and say \"hey man I am buying, what you have for me?\"
;-)

Drug dealers making house calls seems a little unusual unless you have
serious money on offer, or they\'re just small-timers peddling small-time
weed to their friends, in the US it sounds like a good way to get
robbed/killed. Everyone is armed and you have no idea what you\'re
walking into.

In the \'hood at least historically they tend to stick to their \"turf\"
and buyers come to them. But maybe the pandemic has changed even that

here has been a few cases of so called \"white delivery\".
order via snapchat or SMS, and cocain, estacy or similar will be be delivered
to your door, just like a pizza.

if there is a market someone will make a business out of it...

Yeah, amdx likely doesn\'t live in the city or the \'hood for that matter.
Some lady in a town house uses Snapchat to contact the dealer and dealer
feels safe enough. Not entirely safe by any means, but safer.

Maybe amdx\'s bougie neighbors should get off the shit, doing drugs is a
bad idea, \"personal responsibility\" and all that.

 

[John Walliker]

On Monday, 21 February 2022 at 19:41:52 UTC, palli...@gmail.com wrote:

John Walliker wrote:
---------------------------------

** Been dealing with mics, dynamic, true condenser and electrets for over 50 years.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
25 to 30 dB or so equivalent SPL is the norm.
A 10mm dia one one is half the size of any of the above.

FYI: there are two very reliable ways to test the self noise of a mic that has a pre-amp built in.

1. Place it in a silent chamber - a heavy cast iron sphere with a good air seal sited in a quiet room.

2. Place it in a vacuum.

When I visited the UK Knowles factory
** They make tiny hearing aid mics - right?
Very different game.

They do make hearing aid mics, but they make (slightly) larger ones too.

Using a vacuum would give an artificially low noise level as there would
be no brownian movement of air molecules.
** Nonsense - no mic made for audio gets anywhere near that level.
According to Knowles,
about half the noise of a good electret mic comes from the FET and about
half comes from brownian motion of the air molecules.
** Totally false.

I\'m just repeating what I was told. It might be wrong, but why would they make it up?
However, the relative importance of the different noise sources will
vary strongly with microphone diameter, so we might both be right
depending on the mic size.

> A vacuum eliminates all sound transmission to the diaphragm - so is a fair test.
Only if your assertion that brownian motion is negligible is true. Mics are also
sensitive to acceleration, so there would still be a need to connect with mechanically
filtered wires.

There are other 10mm electret capsules that claim a similar noise level,
for example the Primo EM272 and EM273.

** FYI

Condenser mic self noise is mostly low frequency, unlike that from dynamic mics which is close to white noise - rising 6dB with each octave.
As a result, the \"A\" weighting curve has a much bigger effect on condenser models than dynamics.
There are some games being played here with specs.

Most manufacturers will specify their product in a way that makes it look good.
However, there is nothing inherently wrong with using A-weighting as it is
intended to give an approximation to the varying audibility of the noise
with frequency. Ambient noise is usually much higher at low frequencies too,
so poorer low frequency performance from a mic may well not be so noticeable.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
Look a few up.

The first mic I looked at is the Sony ECM100-N which is a small omni-directional electret mic.
Noise floor is 21db(A) or less. So Sony do use A-weighting for their noise specifications.

John

 

[Phil Allison]

John Walliker wrote:
=================

** Been dealing with mics, dynamic, true condenser and electrets for over 50 years.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
25 to 30 dB or so equivalent SPL is the norm.
A 10mm dia one one is half the size of any of the above.

FYI: there are two very reliable ways to test the self noise of a mic that has a pre-amp built in.

1. Place it in a silent chamber - a heavy cast iron sphere with a good air seal sited in a quiet room.

2. Place it in a vacuum.

When I visited the UK Knowles factory
** They make tiny hearing aid mics - right?
Very different game.
They do make hearing aid mics, but they make (slightly) larger ones too.

** Yawnnnnnn.....

Using a vacuum would give an artificially low noise level as there would
be no brownian movement of air molecules.
** Nonsense - no mic made for audio gets anywhere near that level.

According to Knowles,
about half the noise of a good electret mic comes from the FET and about
half comes from brownian motion of the air molecules.
** Totally false.

I\'m just repeating what I was told.

** Not worth posting, cos only YOU know about it.

However, the relative importance of the different noise sources will
vary strongly with microphone diameter, so we might both be right
depending on the mic size.

** Yep. Exactly what I posted. Tiny \"in ear\" mics are not the topic.

A vacuum eliminates all sound transmission to the diaphragm - so is a fair test.

Only if your assertion that brownian motion is negligible is true.

** It is, been dealing with REAL mics, dynamic, true condenser and electrets for over 50 years.
Self noise is always tested with a low noise pre-amp.
Only large diaphragm condensers are truely quiet.



> Mics are also sensitive to acceleration,

** Wot a pedant you are.
\" It it might be true - therefore it is\" nonsense.

Condenser mic self noise is mostly low frequency, unlike that from dynamic mics which is close to white noise - rising 6dB with each octave.
As a result, the \"A\" weighting curve has a much bigger effect on condenser models than dynamics.
There arsome games being played here with specs.

Electrets from makers like Sony, AKG and EV do NOT have exceptional, published noise figures.
Look a few up.

The first mic I looked at is the Sony ECM100-N which is a small omni-directional electret mic.
Noise floor is 21db(A) or less.

** So not 14.

\" Games are being played here with specs\".



...... Phil

 

[amdx]

On 2/21/2022 4:47 PM, Lasse Langwadt Christensen wrote:

mandag den 21. februar 2022 kl. 23.19.27 UTC+1 skrev bitrex:
On 2/21/2022 1:04 AM, Jan Panteltje wrote:
On a sunny day (Sun, 20 Feb 2022 15:31:02 -0800 (PST)) it happened John
Walliker <jrwal...@gmail.com> wrote in
153b314d-6fb5-497a...@googlegroups.com>:


a Gatling gun towards people you think might be drug dealers is maybe
a little unwise.
John
Having lived in Amsterdam the way to find out what they are saying is go over there
and say \"hey man I am buying, what you have for me?\"
;-)

Drug dealers making house calls seems a little unusual unless you have
serious money on offer, or they\'re just small-timers peddling small-time
weed to their friends, in the US it sounds like a good way to get
robbed/killed. Everyone is armed and you have no idea what you\'re
walking into.

In the \'hood at least historically they tend to stick to their \"turf\"
and buyers come to them. But maybe the pandemic has changed even that
here has been a few cases of so called \"white delivery\".
order via snapchat or SMS, and cocain, estacy or similar will be be delivered
to your door, just like a pizza.

if there is a market someone will make a business out of it...



 No they are meth users. But there has also been cocaine and heroin busts.

I have cleaned up needles from my yard and at one point they used my
storage shed

 to hang out and shoot up in, my wife found 3 syringes inside. And as I
said, two women have OD,

 I don\'t think I was clear they died in the house from an OD.


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