Improving old, muddy tapes to digital

I’m looking for general advice of which effects would be best to clean up some old recordings I have & want to preserve digitally.

They’re all voice recordings. What EQ settings would work best to ‘clean up’ muddy vocals? What other effects?
Any help would be great. Thanks!

There are free plug-in effects for Audacity which will add high frequencies e.g. …

You might try tweaking the azimuth of the playback head on your playback machine to see if that helps. Also make sure the heads are clean.

Otherwise, some gentle high frequency boost with the Equalization effect might help.

– Bill

Hmmm, if I knew exactly what I was doing, I’d definitely try the azimuth tweak. But I’ve never done that before & I don’t wanna risk messing up the machine. (it’s an old reel to reel)

I’ll try that plug-in & report back…


Ok, well I followed the link &the instructions read:
"Download the zip file and unzip it into your Audacity plug-ins folder. When you restart Audacity it will appear in the Effects menu. It will be called “Vocal Exciter”.

Did it, but didn’t see “Vocal Exciter”. Guess it doesn’t work with 1.2.6 =/

The effects are in alphabetical order so “Vocal Exiter” is at the bottom of the list : you will have to scroll down the list to see if it is there,
click on the little black triangle at the bottom of the effects list to scroll down.

I think it should still appear on the Audacity effects list even if it doesn’t work.
You have to extract the “.NY” file from the zip file and save a copy of the “.NY” file in the Audacity plug-in folder,
If you don’t extract and just save the zip file to the plug-in folder then the effect wont appear on Audacity effects list.

It might be worth having a quick Google on t’interweb to see if some kind soul has uploaded a manual for your old R2R (you’d be amazed how many manuals for old kit are stored on the 'net) - this should give you guidance on how to adjust the azimuth.


If you’re not up to tweaking the azimuth, at least give the heads a good cleaning. You’d be amazed …

It’s always better to get the best transfer to start with, rather than trying to clean it up later. With high-frequency loss in the transfer you’ll end up increasing the noise when you try to boost the high frequencies later.

– Bill

You can do a decent job on cleaning the heads on the tape recorder with Q-Tips and isopropyl alcohol. Give them a good scrubbing. The recorder should have 2 or 3 heads. Use the alcohol to clean anything the tape comes in contact with as it moves between reels.

If the source material is purely spoken word, no music, you could experiment in Audacity to see which effects help most. I’d first just get the raw recordings into Audacity and saved onto the hard drive. Then make backup copies of the raw recordings. Then experiment. Don’t overload the signal when first recording into Audacity–just get the meters to bounce up above the .5 level on peaks.

Equalizer could be used to roll off high frequencies and hiss

High pass filter could be set at a cutoff frequency of maybe 50, 100, or 200 Hz to see if it reduces “boxiness” or echoing. Boxiness is common on amateur spoken word recordings.

Low pass filter could be set at a cutoff frequency of maybe 6000 or 8000 hz to cut high frequencies above that point. It works similarly to the equalizer.

Audacity’s noise removal effect is excellent at reducing tape hiss if you can find a portion of the recording that has hiss only, no spoken words, to use as a sample. You only need a fraction of a second, so the very beginning or very end of the tape should be suitable for sampling.

That effect should work on Audacity 1.2.x (it’s a “type 1” Nyquist plug-in), though I would not personally recommend the effect for any type of “restoration” work. It is very much an “effect” and is designed more for “creative” sound shaping rather than “cleaning”. (basically it adds a bit of distortion that creates harmonically related overtones to the sound).

Cleaning the tape heads and possibly a bit of Equalisation (as previously suggested) are probably going to be the most beneficial steps.

(“Type 3” plug-ins are not supported by Audacity 1.2.x and will not show up in the menus.)