Need help with something regarding an MP3

This may seem strange to almost everyone that’s even looked at this thread. But anyhow, I’m just wondering, is there a way to replicate the sound in this MP3 file that occurs at the 50 to 57 second point without copying the actual portion mentioned? I’m looking for a way to do it using the pitch or speed adjustment functions. But any method at all is fine with me, except trying to rerecord the original which is something I’ve been trying to do for over a year.

I’m not offended by anyone cracking up laughing just reading this question. But anyhow. It’s a recording of a bus, albeit with a bit of distortion in the file. The bit mentioned is where it gets up to 60kph, and I’d like to know if this input can be modified to portray a file of it sitting at this speed for longer. I don’t want to kill my ears by listening to it in Audacity at high volume repetitively try to figure out what to do.

Thanks in advance.

This is the section from 50s + 01527 samples to 52s + 05697 samples. I’ve reduced some of the crackles using the “Repair” effect (

Loop it as many times as you like by using the “Repeat” effect (

Thanks for the response. But what I actually want to try and do is adjust the input in the section portion of the file (about the 2:10 to 2:45 mark) to where it sounds like the bit at 0:50 to 0:57. Is this possible with Audacity?

If I understand your question correctly, then you could use a “Time Track” like this:

I’m not sure how that feature works. Thanks for pointing it out anyhow though.

The file I initially linked to includes 55kph running. However, I need to be able to modify it using whatever function is available to depict the solid 60kph running in the attached file at approximately the 3:15-3:30 mark.

Also, I have attached another file that shows what I was recording, when actually wanting to get the revs mentioned. Is it possible to modify this one at all? What I’m after is trying to recreate those revs by modifying input at lower speeds so that this can be exported into a full length file of about 6 minutes in length.

Alternatively, are there any other free programs like Audacity that might be able to do this?

If I mess around too much with the Audacity functions, it could be very hard on my ears, so I need to know what to do in advance, rather than just experimenting, and subsequently getting angry with myself. And yes, I do this in spare time. It’s not a job lol.

Thanks again.

Anyone have any further suggestions for this? I still haven’t figured out the magic trick, assuming there is one, and it doesn’t seem like it’s possible now to recapture the original.


Time track demo.gif

I still haven’t figured out a way to modify the audio to something that is similar to portion I mentioned, but nonetheless, is there a way to get rid of this annoying background noise in this file? I unwittingly used incorrect settings, when it turned out that I didn’t need any AGC (Automatic Gain Control) functions at all for this. The only one I use is Limit2, on the odd occasion

I have tried noise reduction, and it hasn’t worked.

The annoying [bubbly] background-noise is compression-artifacts : they are caused by using a low bit-rate , (nothing to do with AGC).

A free plugin called DtBlkFx can be used to reduce the bubbly compression artifacts somewhat …

DtBlkFx plugin showing the 'Motor-Cycle' settings used.png
Motor-Cycle.xml (504 Bytes)

This isn’t as simple as it seems…

If I understand correctly, you have the sound of a bus going 55 kph and you want it to sound like it’s doing 60 kph?

I had to produce a similar effect years ago. There is some Russian specialised hardware/software combo that can do this. It’s aimed at model builders and film crews and comes with samples of different engines, from a V8 to a steam train. It’s not exactly cheap. It has a control input for speed and a built-in DSP that handles the speeding up and down sounds from an array of samples. And if you want, you can record your own samples, but this needs to be done in a sound-wise clean environment and is quite time consuming.

We didn’t use it in the end, for budget and time constraint reasons. I just recorded all the sequences of a real engine we needed. A lot of recording, but easy enough. The actors just had to play along the soundtrack.

I still see no way to do this realistically in a DAW, whatever effect used. Especially since your sample is drowning in some sort of modulation noise. Digital transmission? FSK modulation?

Thanks for the link, but are there any tutorials that show one how to use this function in order to get a desired result? The manual doesn’t pinpoint roughly what I need to do…

With this particular rogue vehicle, it’s very difficult to replicate the revs at 60kph using input of it sitting on 55kph. I have tried everything, including using the increase function to lower the speed and increasing the pitch, whatever I could think of. The file has an issue due to the sensitivity of the mics on the device. It’s a very high pitch sound which caused clipping. It would still do it today even if I used the settings I use now (normal bitrate, standard volume, lo cut, AGC limit2, 4 channel mode). However, the amount of distortion would be less. Unfortunately, the vehicle has been interfered with (as in had some maintenance) and hence this unique…sound can no longer be recorded.

Is there a demo version or something of this software you mentioned which one can squeeze in a few minutes of use to get an example of it’s supposed capability?

I included an .xml file which has the settings I used in DTblkFx , which you can load into DTblkFx as a preset ,
or just manually adjust the settings to match this image …

I’m afraid there isn’t. You have to procure the hardware with the software. And I can’t even find a link to it. Russian sites aren’t very well indexed by Google and even Russian search engines can’t seem to find it.

I’ve never been able to produce this kind of effect, but maybe one of the other forum regulars is smarter…