Bass not cutting through? Loudness could be the answer

[Phil Starr]

 

Anybody listening to music in the 80's will remember the loudness control on their cheap hi-fi. The magic button that made our music come to life, they are still around often with exotic names like Psycho Acoustic boost.  The loudness control worked because it exploited a couple of simple bits of human biology. The same bits of biology that make any bass amp or speaker with a mid scoop fly out of the sales room. It's the sound we all love practicing at home but which sounds s**t when we take it to a gig.

 

So to understand it on the graph a couple of simple bits of physics and then some biology which will hopefully help people with their eq. 

 

So Physics first: sound pressure levels are measured in decibels and are a measure of the sound's energy, how much the air is moving, kind of. It's what is measured by a sound meter and we use it as a measure of sound volume but it isn't reall a measure of how loud something is. Loudness is measured in Phons. The Phons are only the same as the decibels at one frequency 1,000Hz which is right in the middle of the mid range, sort of. Sounds at low frequencies or very high frequencies just aren't as loud for us as at 1,000Hz but at 3,000Hz they sound even louder. If you want hou can play with this online Here  To understand the graph look at the 80Phon line; at 1000Hz it is 80db. Run left to 100Hz and it is 90db. To sound the same volume you need an extra 10db which is 10x the power from your amp/speaker run up to 7kHz and it is again 90db to get the same volume. The graph kind of shows how you would have to set the graphic to get the same perceived volume at 80 phons. As a bassist though the thing to notice is that the settings at low sound levels are different to those at the highest levels. At the quietest you'd need 70db of boost to hear any 20Hz sound at all. At 100phon you'd hear it easily and only need 30db boost for it to be as loud as it is at 100hz. 

 

This is where biology comes in, our ears and brain work together to give the most useful sounds. it's a really clever and subtle system of signal enhancement with genuine survival value. There are lots of quiet bass sounds our body makes, the rumbling of our gut and the grinding of our bones as we move. Imagine moving around the savannah's with the sound of our last meal drowning out the sound of something that want's us to be it's next meal  The sounds we hear best are the dip in the curve 2-5kHz which is vital for understanding speech and screams and cries. Loud bass we need, it means something exciting and dangerous is about to happen, a large animal, falling rocks or something powerful and dangerous. The reason we like a mid scoop becomes apparent. by having the mids lower it sounds like the bass and treble are louder and you get the illusion of your bass coming from a much louder amp. When you turn the amp up to gig volumes you need a lot less boost to bass and treble to get the sound you crave. Loud bass is exciting, an adrenaline rush.

 

So finally we get to bass guitar. Average gig levels are around 100db (as measured on-stage at Glastonbury a few years ago). 80phon is more like pretty loud music in a domestic setting and for sake of argument I'll say close to practice levels. From the graph you'd need around 15db boost to get 100phon at 50Hz and at 80phon you'd need 20db of boost for the same effect. That's 5db difference in the bass between gig and practice levels compared to the mids. So to take your carefully set up tone for the gig you need to turn your bass down 5db at 50hz or the mids up by the same amount to maintain your tone. Given that the mid scoop is often around 5-6db you've pretty much always got to lose it before you play at gig levels. 

 

This isn't the only thing you have to contend with at gigs, room acoustics and the other band members come into the equation too but you have to expect to re-eq when you turn up the volume for a gig to balance your bass and midrange. You'd have to do it for the highs as well except that there is very little hf coming out of your pickups. Cymbals through a powerful PA though......definitely the wrong sort of adrenaline!

 

 

[Franticsmurf]

Thanks for this Phil.

 

It took me a couple of read throughs to get it and my simplistic, non-technical 'take-away' is that if you expect to increase your amp volume between rehearsal and gig, then also expect to change the EQ balance to retain your sound/tone at the new volume. From a practical application point of view, expect to have to lower the bass and treble EQ levels or raise the mids in order to keep the same tone. 

 

I will be trying this at the next rehearsal (using the difference in home practice to band rehearsal volumes). 

[Dan Dare]

I know I bang on about this on here, but, unless you are running bass through the PA, onstage sound is less important than in-room sound. What sounds good when you stand next to your rig can be terrible out in the room. The classic mid-scooped tone with a little low and high end lift can sound like mud in the room. I often find I have to lose some low end and boost the mids to the point where it gets a bit honky for it to work in the mix and in the room.

 

Sound-checking with a long lead or wireless can be very revealing.

[matybigfro]

This is one of those things that I don't get why modelling platforms haven't implemented a solution for.

 

Like in theory it seems pretty simple at a digital level to create eq that matches the fletcher-munson curves with a single control for level that adjusts through the levels so that you can setup patches at room volume and then turn the curve down when playing at practice or gig volume.

[iainbass]

Yep. That lush bedroom tone is lost at the gig without FOH support. Without FOH you need a dry mid forward tone to be heard in the room unless the effect is to produce a boomy wash under the band, but that's very hard to hear on stage.

[crazycloud]

Now you need to learn about room modes...

[Dan Dare]

6 hours ago, crazycloud said:

Now you need to learn about room modes...

 

Nodes, surely?

[crazycloud]

Modes.

[Rosie C]

On 18/10/2025 at 15:21, Phil Starr said:

 

 

We did the Fletcher–Munson curve in uni last week. I have to say you explained it better than my text book!   

 

[Phil Starr]

I'm not getting into discussion of room modes (the collection of resonances in a particular space) here. It merits it's own seperate discussion and is probably better suited to being in the PA section or studio recording. Science works by isolating single variables and investigating and understanding them one at a time. In this little bit all I wanted to do was explain a simple phenomenon which we've all experienced and can easily rectify. It's more psychoacoustics than physics. Maybe a bit of biology.

 

Most of our lives are lived at modest sound levels (70-80db) and the frequencies that are most important for daily living are in the mid-range. The quieter it gets the more the mids are boosted in our brains. If we listen to music quietly we need to add a bit of 'loudness' or the balance sounds weedy. 

 

Bassists in particular need to know of the opposite effect; if we increase the volume above the 80db range then we need to apply anti-loudness, to boost the mids and cut bass (treble in this case is outside of the range of a bass guitar). This will restore the tonal balance that you have set up so carefully at home or in the rehearsal room.

 

This is the bit you as a bassist are in sole charge of. This is about preserving your own tone

 

It's the job of whoever is in charge of the PA to deal with room resonances (or room modes), though in a really awful room they might need you to help out by turning down or reducing you lower frequencies especially if you are using backline only for bass.

[Sparky Mark]

On a different tangent but definitely linked; think of one of your favourite classic bass lines that sounds great, iconic even, in the recording mix. Then Google to see if there's a recording of that bass line in isolation. For me, they are rarely a tone that I would use at home whilst practicing, they often have much more essential mid content. 

Edited 2 hours ago by Sparky Mark

[Lozz196]

7 minutes ago, Sparky Mark said:

On a different tangent but definitely linked; think of one of your favourite classic bass lines that sounds great, iconic even, in the recording mix. Then Google to see if there's a recording of that bass line in isolation. For me, they are rarely a tone that I would use at home whilst practicing, they often have much more essential mid content. 

Agree, quite often those in the mix rich warm tones are, when isolated, middy, scratchy, gainy and clanky.

[EliasMooseblaster]

2 hours ago, Phil Starr said:

Bassists in particular need to know of the opposite effect; if we increase the volume above the 80db range then we need to apply anti-loudness, to boost the mids and cut bass (treble in this case is outside of the range of a bass guitar). This will restore the tonal balance that you have set up so carefully at home or in the rehearsal room.

 

This is the bit you as a bassist are in sole charge of. This is about preserving your own tone

This tallies with my experience: when I mostly played live, I quickly realised the mids were key to the bass having any presence in the mix. If it was a shared/house bass amp, my first order of business was to find any kind of pre-shape/contour/enhance control and turn it right off! Otherwise it was all clacky treble frequencies and deep bass that got in the way of the kick drum.

 

Conversely, as I shifted more to recording music, I realised I could take a lot more mids out without losing the "detail" of the bass tone - and actually get back some clarity. (And believe me, after all those gigs, it took quite a leap of faith for me to turn the mid controls down!)