Q: How can I change the slow tempo from itunes music download. (In iphone; don't own a mac)

Hi, Jsantiago113.  

Thank you for visiting Apple Support Communities.  

I understand that you are concerned with the playback speed of an album purchased vis iTunes.  Does the same issue happen with the same album via iTunes on your computer?  I would recommend deleting this specific album and download the purchased content again directly on your iPhone.  Once this is done, test the playback speed.  Here are the steps that will help you with this process. 

Delete music and audiobooks

 

Remove songs, albums, or audiobooks from the Music app by swiping to the left and tapping delete.

Delete music, movies, podcasts, and other content from your iPhone, iPad, iPod touch

On an iPhone, iPad, or iPod touch

1. Tap Settings > Music and make sure Show All Music is on.
2. Tap the Music app.
3. Find the item that you want to download.
4. Tap the Download  icon.

If you can't find an item in Music using these steps, download it from the iTunes Store app:

 

• iPhone or iPod touch: Tap the iTunes Store app. Then go to More > Purchased. Tap Not on This iPhone or Not on This iPad. Scroll to find the song you want to download, then tap it. Tap the Download  icon next to it. Your item downloads to your device.
• iPad: Tap the iTunes Store app, then tap Purchased. Tap Not on This iPad. Scroll to find the song you want to download, then tap it. Tap the Download  icon next to it. Your item downloads to your device.

Download past purchases from iTunes in the Cloud

-Jason H.