How to Make Audio Sound Muffled – Guide by a Music Producer!

Author: Tomas Morton | Updated: | This post may contain affiliate links.

As a record producer, I love working with artists who enjoy experimenting with sound. It’s even more fun to collaborate with bands that enjoy transforming their organic-sounding recordings into cool, electronically-infused tracks.

I’ve always been a fan of sound design-oriented producers, such as Brian Eno, Trevor Horn, and even Trent Reznor from Nine Inch Nails. There’s just something more satisfying about not making a record sound exactly like what you hear in the live room when the musicians are playing.

One of the coolest skills I’ve mastered is how to make audio sound muffled. Believe it or not, I even get hired sometimes just for this one skill.

So, let’s explore the world of lo-fi music production, and I’ll show you some of my tricks.

Low Pass Filters and EQ

Vintage synthesizers used to sound too bright and harsh, but then low-pass filters came in and saved the day. Bob Moog was the guy who made it all happen when he put a low-pass filter in his Moog modular and Minimoog synthesizers.

Later on, he even made a pedal version called the Moogerfooger, which was a game-changer. Nowadays, low-pass filters are commonly used to create muffled sounds that once required the re-amping of tracks through a natural synthesizer.

Today, there are tons of plugins that make it super easy to automate low-pass sweeps, like the ones by Cytomic, Universal Audio, and obviously FabFilter Volcano. You hear this trick a lot in dance music, where the whole track suddenly gets muffled.

So here’s the deal: You can use a low-pass filter to get that muffled sound by adding a low-pass filter plugin to a track that’s too bright. Then, lower the cutoff frequency from 20 kHz and swoop down to about 80 to 150 Hz. That’s when you’ll hear the muffled sound with a bit of added bass.

If you want a more dramatic effect, turn up the resonance knob too. This will make the peaks come down the spectrum and add some character to the sound.

Most EQ channel strips have a 6 dB, 12 dB, or 24 dB low-pass filter that you can use for this technique. But not all of them have the resonance knob, which is what makes it really special.

LoFi Resampling

Back in the day, there were hardware samplers that were all the rage. Some of the legendary ones like the Ensoniq Mirage, which had 8 bits of resolution, and the AKAI S900 and S950, which had 12 bits, still sell for thousands and are quite popular.

People loved them because they had a way of making your sound muffled and lo-fi by sampling it through not-so-great specs. The audio quality was seriously limited, so it turned any bright and beautiful signal into this gritty, muffled, and super cool version of itself.

This sound became the go-to for the hip-hop community, and electronic acts like Massive Attack and Portishead also used it a lot.

Nowadays, you can get the same effect using software plug-ins like Softube’s OTO Biscuit emulation and Ableton Live’s Redux plugin.

The trick is to lower both the bit rate and the sample rate when you’re doing your lofi resampling. This gives you that super cool muffled effect but in a really musical way.

Convolution Effects

So, there are some really cool convolution effects out there in software land. One of the best is still Audioease’s Altiverb.

It’s a plug-in that has sampled convolution reverbs, but they’ve also gone ahead and sampled responses from old vintage amps and hardware units. You can get a really muffled and dark sound by using a really short and almost non-existent nonlinear reverb response with the wet signal cranked to 100%.

When you set your signal to 100% wetness, then you’re basically getting a snapshot in time of the sampled sound of that machine. Cool, huh?

There’s also this awesome plugin from Waves called Abbey Road Vinyl that, if you use it just right, can lead to some really, really muffled audio. It’s kind of like tape saturation in that vinyl had a really limited frequency spectrum for the highs.

So, when you cut vinyl and lower all the specs to cut the lacquer, it would actually create a really muffled and dark recording.

Some folks would master their records to vinyl, and still do, just to tame some of the high-end. And, of course, with plug-in versions of things, you can take it to the extreme and transform normal recordings into droney, unrecognizable, muffled tracks.

It’s all about that phase distortion! It’s what makes vinyl so unique.


Re-amping is one of my favorite tricks because it’s awesome to get muffled sounds with hardware instead of software plug-ins. I’ve got lots of cool hardware pieces specifically for lo-fi effects.

The art of reamping involves taking any track in your existing DAW and routing a physical output to a piece of gear like a Rackmount saturator, a guitar pedal, or even a speaker in a room with a strategically placed mic to capture the feedback.

I enjoy making natural filter effects by taking a signal from Pro Tools or Live, running it through the Roland Se-02’s input, playing a note, and then re-recording it back into Pro Tools after applying the low pass filter in the synth. This creates awesome synth-like muffled effects but on your audio.

I also like to experiment by putting a small speaker in weird places like a small closet with blankets or even a metal trash can and then putting a tiny microphone to capture the sound of the reflections.

I play one of the audio tracks that I want to muffle through that speaker and then record the signal back in. I purposely try to find dark and dead spots that sound weird.

Tape Saturation

I’m pretty sure that most of you producers and singers have heard of de-essers before. This effect is used to lower the sibilance from certain consonants during a singer’s recording.

Essentially, this effect performs frequency compression. When a high-frequency spikes, it compresses and distorts the harmonics, darkening and taming the sound.

Tape has always been the ultimate frequency compressor. Even though you can make tape sound very hi-fi, it is naturally a harmonic distortion mechanism.

To make it sound good, you have to record it within a specific volume range. Once you go over that range, the tape becomes darker and more distorted, adding third-order harmonics to the signal.

There are two things I love to do with tape: one is to record a signal very loudly until it’s a bit distorted by the tape, then play it back at a slower speed. This yields a beautiful, dark, and distorted muffled sound, which can then be re-recorded into your DAW and added to your production.

There is a piece of gear I’ve been using for many years called the Fatso, made by Empirical Labs. “Fatso” is an anagram for “Full Analog Tape Simulator and Optimizer.”

This machine has two features that can produce beautiful muffled sounds when taken to extremes: the “Warmth” circuit, which performs frequency saturation over all the highs, and the “Transformer” emulation circuit at the end of the signal flow, which distorts the high harmonics to create a beautiful, dark distortion.

The Fatso is a controllable rack-mounted tape machine emulation that, to me, still sounds better than any plug-in.

Universal Audio tried to emulate the Fatso as a plugin, and even though these guys are brilliant at getting 90% of the sound of hardware into software form, this one was, I guess, too hard to emulate. The hardware sounds way better.

If you ever get a chance, record some tracks through it. You’ll be floored!

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About Tomas Morton

Tomas is a record producer, engineer, and synthesizer enthusiast based in Pasadena, CA. He received training at Berklee College of Music in Boston and the Musicians Institute in Hollywood, CA. When not in his studio, he can often be found scouring garage sales or Craigslist ads for vintage gear treasures.

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