# sound velocity calculation in various substances

Discussion in 'General Electronics Discussion' started by kds, May 23, 2010.

1. ### kds

6
0
May 23, 2010
Hello,
I am developing a device for calculating the velocity of soundwaves in rocks and other common substances.

I am planning to purchase ultrasonic transducers for the same.

I just want to know as to what form of signal DC, sine, square etc.. will do my work.
Also, the voltage, power and frequency(for signals other than DC) requirement is not clear.

2. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,497
2,838
Jan 21, 2010
DC will obviously not work.

A square wave has components of a series of frequencies f, 3f, 5f, 7f, ..., so if the frequency is important, a square wave is not optimal (it is quite possible that different frequencies will travel through the substance at different speeds, or interact with discontinuities in a different manner).

A sine wave has a theoretically ideal single frequency.

Some years ago I did some work with 3D seismic survey data. If you want some idea of the complexity of getting sound through rocks then do some research in this area. The issues of matching the signal source to the medium through which you wish sound to travel is the first of many interesting issues.

Seismic survey deliberately uses a wide bandwidth signal so as to get the maximum data, which is somewhat different from what you want, but it serves as a good counter-example that illustrates why you would want a single frequency.

3. ### saurabh17g

72
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Mar 8, 2010
[email protected] : pls tell me the voltage, power and frequency(for signals other than DC) requirement.

4. ### kds

6
0
May 23, 2010
@steve
voltage, power and frequency requirement is still not clear .

5. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,497
2,838
Jan 21, 2010
saurabh12g / kds -- Any reason for posting under 2 user ids?

For seismic survey, the sound source is often something like an explosion, although it is generally done these days with some sort of air canon.

The power you need depends on the size of your sample, and the sensitivity of your receiver. It is something that I simply cannot answer.

6. ### kds

6
0
May 23, 2010
me and kds are working on same project

7. ### 55pilot

434
3
Feb 23, 2010
Busted!

Looks like even managing multiple identities is a beyond your capabilities.

---55p

8. ### 55pilot

434
3
Feb 23, 2010
Since people have stopped answering him under his old ID, it is time to start a new ID and hope to get some answers before he runs out of goodwill on that one.

---55p

9. ### roltex_rohit123

92
0
Oct 12, 2009
We used to calculate the velocity of sound by using resonance using a tuning fork. i dont remember the exact formula but you could google for it.