# Time stretching using FMOD\_DSP\_PITCHSHIFT\_PITCH and setFrequency make the sound unclear and its volume lower **URL:** \ **Category:** FMOD Engine\ **Created:** [October 9, 2020, 1:51pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275 "2020-10-09T13:51:53Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![l3enQ](https://avatars.discourse-cdn.com/v4/letter/l/51bf81/32.png) [@l3enQ](https://qa.fmod.com/u/l3enQ)\ **Post date:** [October 9, 2020, 1:51pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/1 "2020-10-09T13:51:53Z")
Hi, I used FMOD\_DSP\_PITCHSHIFT\_PITCH and set frequency together to lower speed of the song without changing pitch. if I don’t use FMOD\_DSP\_PITCHSHIFT\_PITCH the sound is clear, but when use FMOD\_DSP\_PITCHSHIFT\_PITCH the sound becomes unclear Also I used dsp Info and saw that the vu meter shows lower values when FMOD\_DSP\_PITCHSHIFT\_PITCH is used. How is that and how I can overcome this issue? ---
**Author:** ![joseph](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/joseph/32/264_2.png) [@joseph](https://qa.fmod.com/u/joseph)\ **Post date:** [October 12, 2020, 1:26am UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/2 "2020-10-12T01:26:25Z")
Have you tried increasing FMOD\_DSP\_PITCHSHIFT\_FFTSIZE above the default to reduce “smearing,” as described in the [FMOD-DSP\_PITCHSHIFT](https://www.fmod.com/resources/documentation-api?version=2.1&page=core-api-common-dsp-effects.html#fmod_dsp_pitchshift) documentation? What’s the sample rate of the audio file you’re lowering the play speed of? ---
**Author:** ![l3enQ](https://avatars.discourse-cdn.com/v4/letter/l/51bf81/32.png) [@l3enQ](https://qa.fmod.com/u/l3enQ)\ **Post date:** [October 12, 2020, 6:34pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/3 "2020-10-12T18:34:23Z")
Yes, I have set it to 4096, better quality longer delay but still lower volume sample rate is 44100 ---
**Author:** ![l3enQ](https://avatars.discourse-cdn.com/v4/letter/l/51bf81/32.png) [@l3enQ](https://qa.fmod.com/u/l3enQ)\ **Post date:** [October 27, 2020, 8:19pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/4 "2020-10-27T20:19:47Z")
Is there any updates? what should I do to prevent the issue! ---
**Author:** ![joseph](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/joseph/32/264_2.png) [@joseph](https://qa.fmod.com/u/joseph)\ **Post date:** [October 27, 2020, 10:48pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/5 "2020-10-27T22:48:07Z")
I’ve added this issue to our bug tracker, but we have not yet released a fix. If the change is volume is perceptible and a problem for your game, you should be able to compensate for it by boosting the volume. ---
**Author:** ![l3enQ](https://avatars.discourse-cdn.com/v4/letter/l/51bf81/32.png) [@l3enQ](https://qa.fmod.com/u/l3enQ)\ **Post date:** [October 29, 2020, 8:24pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/6 "2020-10-29T20:24:58Z")
It is a problem and it is perceptible! but the problem is not just the volume, the sound clearance reduction is the main problem. ---
**Author:** ![joseph](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/joseph/32/264_2.png) [@joseph](https://qa.fmod.com/u/joseph)\ **Post date:** [November 6, 2020, 12:00am UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/7 "2020-11-06T00:00:27Z")
> [@l3enQ](#): > > the sound clearance reduction is the main problem. I’m sorry, but I’m not sure I understand. What is “sound clearance reduction?” ---
**Author:** ![orangetek](https://avatars.discourse-cdn.com/v4/letter/o/97f17d/32.png) [@orangetek](https://qa.fmod.com/u/orangetek)\ **Post date:** [November 6, 2020, 9:37pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/8 "2020-11-06T21:37:39Z")
I think he means the sound quality is the main problem ---
**Author:** ![joseph](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/joseph/32/264_2.png) [@joseph](https://qa.fmod.com/u/joseph)\ **Post date:** [November 12, 2020, 6:38am UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/9 "2020-11-12T06:38:03Z")
Assuming that you do mean the reduction in sound quality, [l3enQ](https://qa.fmod.com/u/l3enQ), there is currently no workaround for that issue. ---
**Author:** ![l3enQ](https://avatars.discourse-cdn.com/v4/letter/l/51bf81/32.png) [@l3enQ](https://qa.fmod.com/u/l3enQ)\ **Post date:** [November 12, 2020, 7:22am UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/10 "2020-11-12T07:22:48Z")
yep, I mean kind of sound quality reduction. it is like the bass is killed somehow However I think the problem is with pitch shifting algorithm, and I am seeking for another one to develop it with custom dsp. Although I can find a time stretching algorithm, but it can not be developed by custom dsp, right? what is the best way to develop such things? ---
**Author:** ![joseph](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/joseph/32/264_2.png) [@joseph](https://qa.fmod.com/u/joseph)\ **Post date:** [November 12, 2020, 10:55pm UTC](https://qa.fmod.com/t/time-stretching-using-fmod-dsp-pitchshift-pitch-and-setfrequency-make-the-sound-unclear-and-its-volume-lower/16275/11 "2020-11-12T22:55:31Z")
> [@l3enQ](#): > > However I think the problem is with pitch shifting algorithm, and I am seeking for another one to develop it with custom dsp. > Although I can find a time stretching algorithm, but it can not be developed by custom dsp, right? what is the best way to develop such things? You can find information on developing and using custom DSPs for FMOD Studio [here](https://fmod.com/resources/documentation-studio?version=2.1&page=plugin-reference.html), [here](https://www.fmod.com/resources/documentation-api?version=2.1&page=white-papers-dsp-architecture.html), and [here](https://www.fmod.com/resources/documentation-api?version=2.1&page=white-papers-dsp-plugin-api.html).