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### Sounds of Music C

Posted: September 13th, 2020, 11:50 am
Ok I'm bored so here goes nothing

1. What is the beat frequency that results from the interference of two sounds with frequencies 400.0 Hz and 420.0 Hz?
2. You measure a sound's intensity as 90.0 dB at 4.00 m away from the source. What is its intensity in W/m^2?
3. What would be the intensity in dB of the above sound at 12.00 m from the source?

### Re: Sounds of Music C

Posted: October 11th, 2020, 6:19 am
SciolyMaster wrote:
September 13th, 2020, 11:50 am
Ok I'm bored so here goes nothing

1. What is the beat frequency that results from the interference of two sounds with frequencies 400.0 Hz and 420.0 Hz?
2. You measure a sound's intensity as 90.0 dB at 4.00 m away from the source. What is its intensity in W/m^2?
3. What would be the intensity in dB of the above sound at 12.00 m from the source?
```1) 20.0 Hz
2) 10^-3 W/m^2 (I'm using 10^-12 W/m^2 as 0 dB, but that may not be right?)
3) 10.0 dB```

### Re: Sounds of Music C

Posted: October 13th, 2020, 6:59 am
UTF-8 U+6211 U+662F wrote:
October 11th, 2020, 6:19 am
SciolyMaster wrote:
September 13th, 2020, 11:50 am
Ok I'm bored so here goes nothing

1. What is the beat frequency that results from the interference of two sounds with frequencies 400.0 Hz and 420.0 Hz?
2. You measure a sound's intensity as 90.0 dB at 4.00 m away from the source. What is its intensity in W/m^2?
3. What would be the intensity in dB of the above sound at 12.00 m from the source?
```1) 20.0 Hz
2) 10^-3 W/m^2 (I'm using 10^-12 W/m^2 as 0 dB, but that may not be right?)
3) 10.0 dB```
Wouldn't it be (10^-3)/9 = 0.000111 W/m^2 = 80.5dB?

### Re: Sounds of Music C

Posted: October 13th, 2020, 8:51 am
builderguy135 wrote:
October 13th, 2020, 6:59 am
UTF-8 U+6211 U+662F wrote:
October 11th, 2020, 6:19 am
SciolyMaster wrote:
September 13th, 2020, 11:50 am
Ok I'm bored so here goes nothing

1. What is the beat frequency that results from the interference of two sounds with frequencies 400.0 Hz and 420.0 Hz?
2. You measure a sound's intensity as 90.0 dB at 4.00 m away from the source. What is its intensity in W/m^2?
3. What would be the intensity in dB of the above sound at 12.00 m from the source?
```1) 20.0 Hz
2) 10^-3 W/m^2 (I'm using 10^-12 W/m^2 as 0 dB, but that may not be right?)
3) 10.0 dB```
Wouldn't it be (10^-3)/9 = 0.000111 W/m^2 = 80.5dB?
Not sure what you mean here, but a drop of 10 dB corresponds to dividing the intensity by 10..

### Re: Sounds of Music C

Posted: October 13th, 2020, 10:10 am
UTF-8 U+6211 U+662F wrote:
October 13th, 2020, 8:51 am
builderguy135 wrote:
October 13th, 2020, 6:59 am
UTF-8 U+6211 U+662F wrote:
October 11th, 2020, 6:19 am
```1) 20.0 Hz
2) 10^-3 W/m^2 (I'm using 10^-12 W/m^2 as 0 dB, but that may not be right?)
3) 10.0 dB```
Wouldn't it be (10^-3)/9 = 0.000111 W/m^2 = 80.5dB?
Not sure what you mean here, but a drop of 10 dB corresponds to dividing the intensity by 10..
No, he is correct. Decibels are a measure of intensity level, not intensity. Intensity is measured in W/m^2, which means you must convert decibels to W/m^2 first, then divide by 9, then convert back to decibels.

### Re: Sounds of Music C

Posted: October 13th, 2020, 11:52 am
Umaroth wrote:
October 13th, 2020, 10:10 am
UTF-8 U+6211 U+662F wrote:
October 13th, 2020, 8:51 am
builderguy135 wrote:
October 13th, 2020, 6:59 am

Wouldn't it be (10^-3)/9 = 0.000111 W/m^2 = 80.5dB?
Not sure what you mean here, but a drop of 10 dB corresponds to dividing the intensity by 10..
No, he is correct. Decibels are a measure of intensity level, not intensity. Intensity is measured in W/m^2, which means you must convert decibels to W/m^2 first, then divide by 9, then convert back to decibels.
Oops I thought he was talking about b yeah c I meant to subtract 90 by 10log 9, my bad.

Assuming it's my turn to go, define syntonic comma and give the ratio associated with it.

### Re: Sounds of Music C

Posted: October 13th, 2020, 1:11 pm
On second thought, this might be too in-depth a question to ask for this event, so here's another question:

What's the leading tone in the key of C minor?

### Re: Sounds of Music C

Posted: October 13th, 2020, 6:25 pm
UTF-8 U+6211 U+662F wrote:
October 13th, 2020, 1:11 pm
On second thought, this might be too in-depth a question to ask for this event, so here's another question:

What's the leading tone in the key of C minor?
B

### Re: Sounds of Music C

Posted: October 13th, 2020, 6:41 pm
nobodynobody wrote:
October 13th, 2020, 6:25 pm
UTF-8 U+6211 U+662F wrote:
October 13th, 2020, 1:11 pm
On second thought, this might be too in-depth a question to ask for this event, so here's another question:

What's the leading tone in the key of C minor?
`B`
Yep! Make sure to use

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``[answer]``