SSD is a MUST-HAVE when using Audacity?

Hi, first of all, thanks for this amazing program. I’ve been using it for years and it’s great, really really helpful. Thanks developers and all the staff/people related with it.
Well, I use it for 2 things:

1. Music
When learning songs with guitar, I use a lot Audacity, cause it can reduce a lot the speed WITHOUT compromising the audio quality, change pitch, replay over and over again the same section, show the waves of the sound, invert effect… you know, really powerful tool.

I miss here some real-time effects, something like change the pitch on-the-go, without processing, and the same with speed. Anyway, as I have a powerful laptop, it takes just 3-5 seconds to change the pitch or the speed, so it’s OK.

2. Movies
a) I use also Audacity when I wanna sync a spanish audio film file to an english movie. I extract both spanish and english audios. I load them in Audacity. We’re talking about 2 hours length tracks, with 6 channels, 1.5GB. This step is really slow, DUE to the HDD. Very first reason to use a SSD.

b) Usually, spanish movies are 25fps, and american movies are 24fps, so the first thing I always have to do is reduce the speed of the spanish audio, so it’s longer and fits the english track. Change the tempo of this kind of files takes also some serious time. Second reason to use a SSD.

c) Then it comes the hard work, I have to compare both audios. As I usually have to add the spanish audio to the english movie, the spanish audio is the one that is gonna be edited, and the english is there for comparison. Now, I zoom in and compare both files, viewing 30 seconds in the screen, so I can work comfortably. Then delete audios of extra scenes, or add the english audio when english movie have extra scenes. When I zoom in/out and move between sections, it takes seconds to respond. Third reason to use a SSD.

d) Once the spanish audio is done and synced with the english track, I have to export it. This is CPU business. I have an Intel i7 4700MQ quad-core processor, with hyperthreading, so I have 8 threads running @2.4GHz, but as I have Turboboost 2.0, this can go up to 2.9-3.4GHz. When I export the project, there’s only one core in use, 2 threads show some movement, the other 6 threads are idle. So I’m not squeezing at all the power of my 4 cores. So, this exporting process takes a lot of time too. I don’t know if it’s planned to support multi-core exporting in Audacity, it would be really really helpful, cause that could reduce the exporting time almost 4 times.


Another Question: when I import a track to Audacity, where is it being loaded? I though RAM, but I think I’m wrong.

Audacity may have real-time preview of effects some time in the next year or so.

You can use On-Demand Loading for WAV files.

But otherwise, large files could still take a few minutes to import even if the audio file and the Audacity temporary directory were both on an SSD. As I understand it, combined read/write is not always much quicker than with an HDD.

Audacity does already use multiple cores assuming you specify this in Windows Task Manager (at least it uses both cores on my dual core machine). But using all cores doesn’t speed up processing much because Audacity does little or no running of the same task in parallel threads.

Audacity has not used RAM for audio data since version 2.0.2. Imported data is written to the drive specified in Audacity’s Directories Preferences (for temporary data where you have never saved a project) or to the drive you choose when you save a project.


I didn’t mean a preview of an effect so I can have an idea of how it will sound. I meant change the speed or pitch instantly, without processing data.

I’ve been watching Windows 8.1 Task Manager’s Performance Tab and it only showed movement in 2 out of 8 threads. So there was only 1 core processing the data, using its both two threads. Unless it was core1 thread #1 and core2 thread #1. I don’t know.

Thanks, Gale.

There is Time Tracks although you have to draw the curve first.

It sounds like you are asking for a real-time Transcription Toolbar ?

Have you looked in Resource Monitor? There is a button for it at the bottom of the “Performance” tab.

Processor affinity (how many cores are used) can be set by right-clicking over audacity.exe on the “Details” tab of Task Manager.


No, I just mean change the speed or the pitch without waiting, just like you do in VLC, where you can play a song, and reduce its speed instantly. No processing, no new toolbars. You know, on-the-go, a single bar or option where you can set x0.15 and the playback start to play x0.15 times its speed. Same with pitch.

I didn’t know that, but I’ve done it and everything was checked. Here’s a screenshot of an exporting:

It never uses more than 1 thread as you can see, and this is weird cause it has changed between threads a few times. When I export, it normally uses 1 thread all the time.

Audacity has that now, except the choice is only for speed, and you have to restart playback from the cursor rather than change the speed while you’re playing. And except that we require to use a special Play button.

To see the option, open Keyboard Preferences, change to the “Command” category and look for “Adjust Playback Speed”. Set a keyboard shortcut for “Adjust Playback Speed” then OK Preferences and use the shortcut.

On my Dual Core on Windows 8.1, it uses both CPU’s equally. But you have a more advanced machine and it probably underlines the fact that Audacity isn’t using multiple threads to speed up export.

But try thrashing the export a bit harder. Change project rate to 8000 Hz then generate a 30 minute tone. Change project rate to 384000 Hz then export that.


Yeah, but it changes the pitch, so it’s not useful when trying to learn a part of a song, cause you’re out of tune. You have to reset the playback, and when you click in the upper bar, it plays at normal speed. It’s not what I was looking for. It’s just the “Change tempo” feature, but without processing the data, just playback at that speed everytime until you change it.

All the rest is clear. :slight_smile:

OK so I still think we are looking at a real time Transcription Toolbar, except it does Change Tempo and Change Pitch as well as Change Speed (also affecting pitch).

Like this?


Yeah, something like that, but I don’t know what Transcription Toolbar is. I’d love to have 2 buttons in the interface of Audacity to change the pitch and tempo of the playback, without processing data.

See Transcription Toolbar - Audacity Manual .

You set the playback speed then click its special Play button to play at that speed. But that speed change affects pitch too.


Oh, it is that bar. Since it changes pitch too, it’s not useful for what I want. I want something like that but that changes tempo only, and if possible a more accurate method to set the tempo.

You can set the speed to several decimal points of accuracy by double-clicking on the slider