Looks like the Presonus is a serious bit of kit. I think you are suggesting that one input is the PC and the other is the laptop CD player with the output to your stereo.

In this case, I would take an audio CD and use MMW4's Tools / Rip Audio CD option in order to create a FLAC format file for each track. Try with a sample rate of 48000 Hz (or even 96000 Hz) and 24 bits per sample. You have an option to set the level of compression - try something towards the right i.e. slower conversion but more compression.

Often this Rip option will "lookup" the <Album Artist>, <Album>, <Track #> and <Title> so you can construct a drive / path to save your rip e.g. E:\Downloads\<Album Artist>\<Album>\<Title>.

Repeat the previous but create new MP3 using - at least - the Standard (Fast) Preset (VBR ~192kbps - Very High Quality)

Incidentally, MMW5 has more options to "verify" the ripped tracks, read the CD to correct for Jitter.

Once ripped, you can compare the CD vs "original" MP3 vs FLAC and "new" MP3. In this way you can make a judgement about whether the original MP3 quality is the source of the lower quality output. It may also point you in the direction of repeating the rips of your CDs - either using a higher quality MP3 or a FLAC format.

Personally, I would explore this before looking into alternative output plugins.

There is an alternative input plugin on the MM website called MAD. Could I use that to get better audio quality out of my existing MP3s?

Thank you Ian, I run my Laptop through A Presonus audio interface into my stereo system. My MP3s are usually 320 bitrate. When I compare that to an Identical song playing on my laptop CD player, I hear a big difference in clarity definition upper end sizzle. I was wondering what I could do to the existing MP3s to enhance them creating the overtones that don't seem to be there anymore even at 320?

Are you comparing the sound of the MP3s vs CDs on exactly the same device i.e. your PC / PC Speakers?

You can check the "quality" of your MP3s using MMW4 by selecting a file and viewing the properties of the file - specifically the sample rate and bit rate. For MP3, 44100 Hz and 320 kbps are typical for music, but you may find podcasts and audiobooks lower then this. Even as low as 16000 Hz and 32 kbps. You could even add columns to MMW4 "all files" display to show (and sort) by Bite Rate and Sample Rate.

Alternative file formats - for example FLAC - offer higher quality that can go as high as 192000 Hz and ~8000 kbps. BUT will your device(s) be able to handle this? Typically CDs have a 16 bit depth and 44100 Hz sample rate. "Hi-Res" whilst not strictly defined might be considered as 24 bit or even 32 bit with a sample rate of 96000 Hz or a ridiculously high 384000 Hz! These numbers are in excess of of the capabilities of headphones / speakers and indeed our ears.

Also, I understand that Android "resamples" audio to 48000 Hz and that you would need special apps to "bypass" this limitation. Some mobile phones / headphone combinations offer support for High Resolution through digital enhancements (DSEE) or proprietary coding (LDAC). So a lot will depend on the device / speakers / headphones / sound card etc! Oh, and of course your ears.

You might want to try Ripping a favourite CD - using MMW4 - into various formats / qualities and doing some specific tests. This way you can find out what suit you best. Also consider the storage space / costs plus synchronisation / backup times. MP3 files (a few hundred kB to a few MB) swell by a factor of say 10-100 with higher quality file formats and can even get into a few GB if the track is quite long!

I run a PC with an optical audio out to a modest second hand sound bar. I can barely tell the difference between a good high quality MP3 and a modest FLAC file. However, using good blue tooth headphones and an Android device with DSEE / LDAC I can discern the higher quality. This is despite the abuse my hearing has suffered over the decades.

Hope this helps.

I am still using MM 4.1. I have Windows 7 and it won't let me install anything newer. I have a very large MP3 collection. All in the highest quality. But they don't sound anywhere near as good as my CDs. So I'm wondering if there is anything I can do to improve the sound of my MP3s. I don't know a ot abut this technical stuff, but I heard that input plugins can affect the sound. I only have what MM originally came with. Can you guys help me get the most out of my MP3s?
Thank you