Hi there everyone. I am new to this forum and a complete novice when it comes to sound editing! My biggest problem is that I don’t necessarily know the correct terminology so if this question has been asked before please forgive me. To the question - I build model boats and at the moment am building a large Motor Torpedo Boat which runs on 4 electric motors. The real ones had 4 Packard petrol engines and I have found a sound clip of one of these engines starting up, running and then closing down. If I can I want to superimpose (if that is the correct word) 4 engines starting and running, one after the other. I have tried copying the startup bit and pasting it after the first startup and that works but obviously the sound of the first engine running is missing until all the engine startups have been completed. I want the engine running sound to still be there on each startup. Also the engines on these boats were VERY loud, how do I increase the output volume without distortion.
I hope you can follow my meaning and any help would be much appreciated.

Create four tracks in your project, one for each engine. On each track put the startup sound followed by many copies (essentially a loop) of the running sound. Use the Time Shift tool to move the starting times of the various engines to where you want.

When you mix the four tracks together you may get clipping distortion, so use the Track Gain Slider to reduce the volume of each track so that the final mix is not distorted. To make the overall mix louder, turn up the speaker volume.

– Bill


I am comparing the sound of copper clad quarters (1965 and newer) to that of 1964 and older 90% silver quarters.

Could Audacity 2.0.0 Unicode software allow the user to first create a control graph of the 90% silver quarter frequency in a blue color for example?

Then could an unknown quarter’s frequency results be superimposed upon the same x/y coordinate graph used for the control graph but as a green color, for example.

In summary this procedure would allow the user to superimpose both the blue and green frequency graphs of each coin directly on top of one another on the same graph.

This result would permit quicker and more accurate differentiation between coins that may be only slightly different from one another etc.


It is generally better to start a new topic for a new question rather than tag it onto the end of another topic.

No, unfortunately Audacity can not currently superimpose multiple spectrum plots. This is already a feature request on the wiki so I’ve added your vote.
“Multiple spectra window: (10 votes) Plot multiple spectra for different tracks/regions in the same project e.g. Audition has four buttons to hold spectra. Currently different spectra must be in different projects. Multiple plots in different colours in the same window would aid comparing spectra.”

You can “fake” that feature by taking screenshots with a graphics program such as Gimp or PhotoShop and superimposing the images as layers (not very convenient though).