easy way to calibrate audio frequency generator?

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I have a Heathkit ET-3100 electronic design experimenter that has a very  
basic sine/ square wave function generator.  Controls all analog and no  
scale really.  Output is from 200 Hz - 2 Khz on "low" and 2 Khz to 20  
Khz on "high".  Exact frequency depends on where the pot is adjusted.  
How can I calibrate this to be more precise, preferably in a simple way?

Re: easy way to calibrate audio frequency generator?
On Sunday, February 28, 2021 at 4:27:15 PM UTC-5, Tinkerer wrote:
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Frequency counter.  They have cheap Chinese kits on ebay that should give you readings close enough to what that generator would be used for.


Re: easy way to calibrate audio frequency generator?
 Tinkerer wrote:
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** Time to get a Digital Multimeter with a frequency range.
     Not crazy expensive and damn useful.  
    
    Plus very accurate.  



......   Phil  

  

Re: easy way to calibrate audio frequency generator?
On 28/02/2021 3:27 pm, Tinkerer wrote:
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y basic  

scale really.  
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? Exact  
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s to be  
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Borrow a freq counter?


Re: easy way to calibrate audio frequency generator?
On 28/02/2021 21:27, Tinkerer wrote:
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One of those cheap digital guitar tuners things might point you in the  
right direction ? (everybody knows somebody who plays the guitar)

I believe there are smartphone apps which display the frequency of the  
signal coming in to the microphone - whilst recording it. Theres one (of  
many) examples at https://audio-frequency-counter.soft112.com

Or if you know anybody with Cubase (or similar) recording software you  
could get them  to fire up the built in digital tuner tool and see it in  
glorious technicolor

AT

Re: easy way to calibrate audio frequency generator?
Cheap USB microphone, laptop, Audacity?  (Audacity is free recording software with lots of extras, does frequency, etc)  

Re: easy way to calibrate audio frequency generator?
On 3/1/21 12:04 PM, Tim R wrote:
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Great idea.  I have Audacity.  I could just play the audio output and  
either capture with mic or feed into soundcard and then see what it is  
in Audacity.  I think that's what I'll do, although I like Phil's  
suggestion of a DVM with freq counter, been keeping an eye out for one.

Re: easy way to calibrate audio frequency generator?
On 01/03/2021 18:04, Tim R wrote:
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If you have a PC with a decent sound card you don't need an audio
frequency generator :-)

Re: easy way to calibrate audio frequency generator?

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Beat it with mains hum.  This should work on the low range and at least
part of the way up the high range.

--  
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
We've slightly trimmed the long signature. Click to see the full one.
Re: easy way to calibrate audio frequency generator?
 Liz Tuddenham wrote:

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** You need to explain that idea.  

The OP  seems to have no test gear or clue.  

......  Phil


Re: easy way to calibrate audio frequency generator?
On 3/1/21 2:46 PM, Liz Tuddenham wrote:
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Not sure what that means, unless you mean a harmonic of 50/60 Hz.  It  
might be possible to beat by ear if the PC generates the tone and I  
adjust the generator until it matches by ear, but I think I'm just going  
to use Audacity and/or a DWM with freq ctr as suggested by Phil.

Re: easy way to calibrate audio frequency generator?
On 3/1/2021 1:09 PM, Tinkerer wrote:
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Google  Online Music Tuner  In the US the note A is generally considered  
440HZ  This one gives the frequency in Hz  https://bit.ly/383gzou

Re: easy way to calibrate audio frequency generator?
On 02/03/2021 05:09, Bennett wrote:
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Speaking of which ... I believe some musicians are able to tune their  
instruments by using the dial tone from a landline as a reference.

AT

Re: easy way to calibrate audio frequency generator?
 Abandoned_Trolley wrote:
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** But only after taking a huge dose of Meth first.


......   Phil  


Re: easy way to calibrate audio frequency generator?
On Tuesday, March 2, 2021 at 5:01:10 AM UTC-5, Abandoned_Trolley wrote:

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Wiki says the dial tone is a combination of 350 and 440 Hz.  That would be  
an F major chord, minus the fifth.  I guess you could do that.  Youtube had
 a 12 hour long recording of a dial tone.  I just tried to tune a guitar A  
string to that, came out 3 cents sharp by my tuner.  But my tuner hears the
 dial tone as an F.  The youtube version sounds like a square wave to my ea
rs though.  

The 60 cycle power hum doesn't work, it is halfway between a Bb (58) and a  
B natural (62).



Re: easy way to calibrate audio frequency generator?

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That's a great idea, but it probably mean FA to most people.

Musicians, on the other hand ... :)

--  
--------------------------------------+------------------------------------
Mike Brown: mjb[-at-]signal11.org.uk  |    http://www.signal11.org.uk

Re: easy way to calibrate audio frequency generator?
On Tuesday, March 2, 2021 at 4:22:06 PM UTC-5, Mike wrote:
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Doesn't mean much to musicians either.

Most of us don't have land lines.

Most of us do have cell phones and you can get free tuning apps on them.  
  

Or you can get a decent electronic tuner for $20.  

Those two things have made a huge difference in stabilizing a pitch center.
  Years back you never knew what pitch a band was going to have - might be  
440, 415, 175, who knows?  You had to be prepared to accommodate, and some  
instruments could only be tuned so far.  Now amateurs don't play any better
 in tune, but they play out of tune around an agreed upon pitch, and that m
akes it a lot easier.

What you hear on recordings is always autotuned.  I don't understand how th
at works, but it may be gradually training people to expect things to be in
 tune.  Except Sailor Sabor, of course, who holds the record for the most o
ut of tune National Anthem ever, at the CPAC 2021 last week.

Re: easy way to calibrate audio frequency generator?
On 3/3/21 10:29 am, Tim R wrote:
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Except Sailor Sabor, of course, who holds the record for the most out of  
tune National Anthem ever, at the CPAC 2021 last week.


Your entire National Anthem is out of tune with the 21st century, and  
the 20th too if it comes to that. Try reading the lyrics sometime and  
think about how it sounds to anyone not born American.

Re: easy way to calibrate audio frequency generator?
 Clifford Heath wrote:

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** Yeah  -  the  " Star Bangled Spanner"  is looking a bit worn out.

  Probably get cancelled soon as "racist".  

  Maybe they could adopt:  "'Born in the USA"  ?  

  Oh shit, that's racist too !!  


.....  Phil  

Re: easy way to calibrate audio frequency generator?
Given that it started as a drinking song (in 1775) - it was, is and remains quite apt.  


https://www.youtube.com/watch?v=8KcHg5ZOIgU


Peter Wieck
Melrose Park, PA  

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