Can we really boost bass?

[alaios]

So I see that many EQs try to boost bass and I wonder if this is an attempted bad fix for a speaker that does not go too low.
For example the EQ loudness in my Wiim is boosting lower frequencies and boosts a bit the higher frequencies. Can those boosted lower frequencies just increase distortion at the speaker? What is the measurement to show us that?

Also would have not been "smarter" to to just reduce the mid ranges instead of boosting bass and treble ? Would not that have been safer?

 

[staticV3]

One often misunderstood part of digital EQ is that boosting bass will achieve exactly the same result as reducing mids and highs, as long as you do it correctly by also applying the appropriate pre amplification.

All that matters is the final filter response, not what kind of individual filter configuration was used to achieve it.

You can very well boost a speaker's bass response with EQ.
At some point though, the speaker will reach its limit, which will result in distortion, limiting, compression, etc.

By how much you can boost bass depends on the type of content that you play and how loud you play it.

 

[alaios]

So then I am right on what I have written? Since we care for the final filter response it would have been better if they have removed mids instead of boosting bass. But then are not the Wiim enginners smarter than me? That I am just a random internet guy?

 

[staticV3]

So I see that many EQs try to boost bass and I wonder if this is an attempted bad fix for a speaker that does not go too low.

No. It's a perfectly viable solution, also used by many manufacturers.

Can those boosted lower frequencies just increase distortion at the speaker?

If your speaker has already reached its limit and is distorting heavily, then boosting bass even more will only result in higher distortion.

If on the other hand there is no audible bass distortion coming from your speakers, then you can safely apply EQ to boost the bass response.

What is the measurement to show us that?

THD, MD, Compression

Also would have not been "smarter" to to just reduce the mid ranges instead of boosting bass and treble ? Would not that have been safer?

Neither smarter not safer, since, as I said before, it's the effective filter response that matters.

 

[mj30250]

So I see that many EQs try to boost bass and I wonder if this is an attempted bad fix for a speaker that does not go too low.

Whether it's "bad" or not depends on different variables. Remember that the room has a massive influence on bass response. Addressing the room and speaker positioning is the first step to getting bass in order. Many people choose to apply a boost to bass and it can often be done with satisfying results. Of course, the capabilities of your speakers is a key component. If your mains roll off at 120Hz, boosting 40Hz to 100Hz is not likely to work well (in this case, buy different speakers and / or integrate subs).

For example the EQ loudness in my Wiim is boosting lower frequencies and boosts a bit the higher frequencies. Can those boosted lower frequencies just increase distortion at the speaker? What is the measurement to show us that?

They can increase distortion, and in an objective sense, they likely do, but whether this distortion is at all audible is another matter. REW and a measurement mic can be used to measure distortion in-room.

Also would have not been "smarter" to to just reduce the mid ranges instead of boosting bass and treble ? Would not that have been safer?

This is sort of six of one, half dozen of the other. Ultimately you are after the "best" overall response at the volumes you will be listening at. If you are looking for shelved up bass, yes, you can reduce the higher frequencies. But then, what happens when you turn the volume up? The bass goes up with it, so you potentially arrive at the same situation.

 

[alaios]

No. It's a perfectly viable solution, also used by many manufacturers.


If your speaker has already reached its limit and is distorting heavily, then boosting bass even more will only result in higher distortion.

If on the other hand there is no audible bass distortion coming from your speakers, then you can safely apply EQ to boost the bass response.


THD, MD, Compression


Neither smarter not safer, since, as I said before, it's the effective filter response that matters.

so what you say is that their boosted bass response does not mean I will be listening really at higher volumes (where the distortion will show much faster)

 

[staticV3]

so what you say is that their boosted bass response does not mean I will be listening really at higher volumes (where the distortion will show much faster)

Boosting bass will boost volume.

When you listen quietly, then you can boost a lot before your speakers complain.

When you listen super loud, then you're already close to the speakers' limits. Boosting bass by just a little while listening at that volume, may already push the speakers beyond what they can do.

 

[Vincent Kars]

Since we care for the final filter response it would have been better if they have removed mids instead of boosting bass.

Depends.
If you want more bass, boosting it is the obvious answer. However, if you boost to much (certainly with hot recordings) you will hit 0 dBFS (the loudest possible signal at the digital side) so digital clipping will occur.
The trick is to boost to your hearts content but lower the pre-amp of the EQ software with the highest boost level to avoid clipping

 

[RayDunzl]

So I see that many EQs try to boost bass and I wonder if this is an attempted bad fix for a speaker that does not go too low.
For example the EQ loudness in my Wiim is boosting lower frequencies and boosts a bit the higher frequencies. Can those boosted lower frequencies just increase distortion at the speaker? What is the measurement to show us that?

Also would have not been "smarter" to to just reduce the mid ranges instead of boosting bass and treble ? Would not that have been safer?

If you are boosting in the digital domain on a typical modern popular recording, you will most likely induce severe digital clipping..

First, reduce the level of the whole track by the amount of boost desired.

Original
8dB bass boost (clipped)
Reduce track by 8dB, then boost the bass 8dB

 

[MRC01]

So I see that many EQs try to boost bass and I wonder if this is an attempted bad fix for a speaker that does not go too low.
...
Also would have not been "smarter" to to just reduce the mid ranges instead of boosting bass and treble ? Would not that have been safer?

If you want more bass I think it is smarter to reduce the mid-treble. It does the same thing without any risk of clipping and obviates the need for negative gain before the EQ is applied.

 

[sergeauckland]

Rather depends on where one boosts the bass. If it's done in DSP as part of the loudspeaker's active crossover, then I don't see a problem. The boost in bass matches the drop-off in bass of the loudspeaker system. The DSP can also dynamically reduce the amount of boost as the loudspeaker gets closer to its excursion limits and/or amplifier output limits, so protecting the driver.

Boosting the bass or reducing the mid/top have the same result, an overall flat response. By reducing the mid/top, one just has to turn up the volume more, thus still reducing headroom.

S.

 

[DVDdoug]

Note that the "preamp" setting on a digital EQ is normally used for attenuation ("negative amplification").

In fact, when you boost the bass digitally you usually end-up reducing the overall loudness, because even if the bass is digitally "maximized" our ears are less sensitive to bass. And your speakers are probably weak in the bass range, or you wouldn't need to boost. If you have enough analog gain and amplifier power, and if the speakers can handle the additional power, you can overcome that.

If you have a small 5-inch woofer, you'll never get "realistic" bass you can feel in your body. Size isn't everything but "physics" do come-into play.

Ported woofers tend to roll-off quickly below the -3dB point. Depending on where they are "tuned" boosting the deep bass can make the woofer move a lot but the sound gets canceled by the soundwaves from the port. (A bit higher in the bass range where the port is "working", the sound from the port is in-phase and it reinforces the direct sound from the woofer.)

Sealed woofers tend to start rolling-off at a higher frequency (just a generality, not always true) but they tend to have a more gentle slope. So with EQ you can often get very-deep bass and beat the ported design.

When standing waves in the room create a null (where the waves cancel at certain frequencies and at certain places in the room) that's virtually impossible to fix with EQ. But EQ can help with anti-nodes where you get a boost. ...Bass traps will reduce the reflected waves, smoothing the dips (nodes) and the bumps (anti-nodes).

 

[Keith_W]

For example the EQ loudness in my Wiim is boosting lower frequencies and boosts a bit the higher frequencies. Can those boosted lower frequencies just increase distortion at the speaker? What is the measurement to show us that?

Absolutely. If you boost low frequencies inappropriately, you WILL increase distortion. I picked a speaker at random from Amir's review database, but let us look at the Polk Audio Signature S15 as an example of a small speaker which is deficient in bass frequencies. This is Amir's measured FR:

OK so we see that bass drops off sharply at 90Hz. It is 85dB at 90Hz, and 73dB at 45Hz ... i.e. a drop of 12dB/octave. Can this be boosted with EQ? Let's look at his distortion measurements:

We see that distortion goes off the scale <70Hz, even at 86dB. At 96dB it is even worse. So: this speaker is NOT a candidate for bass boost.

You could look at other speakers to see how they would perform, but in general - your bass boost is limited by onset of audible distortion. The actual limit depends on you, because you may be able to tolerate more audible distortion than other people. Some people hate the idea of distortion and set their limits lower so that nothing ever distorts. And let's face it, this is not a mission critical application of audio here. You are not a submarine sonar operator where life or death depends on clean signal So for me, I tolerate some distortion because to get rid of it requires purchase of more equipment.

You can perform your own distortion measurements. You need a microphone, a PC, REW, an SPL meter, and a microphone tripod. The "standard" method is: place your mic 1m away from the speaker and play a 1kHz test tone. Adjust the volume of the tone so that it is 86dB, and adjust the gain on the mic in REW so that it reads 86dB. However, room reflections will affect your distortion measurements, so there is a lower limit where these will be meaningful, and it will not capture bass distortion. So I suggest placing your mic even closer, i.e. almost touching the speaker. You might have to measure driver and port separately. Then perform a sweep, and click on the "distortion" tab. You will see a trace similar to Amir's. Repeat the test at 96dB and as loud as the speaker will go (wear hearing protection!).

 

[alaios]

No. It's a perfectly viable solution, also used by many manufacturers.


If your speaker has already reached its limit and is distorting heavily, then boosting bass even more will only result in higher distortion.

If on the other hand there is no audible bass distortion coming from your speakers, then you can safely apply EQ to boost the bass response.


THD, MD, Compression


Neither smarter not safer, since, as I said before, it's the effective filter response that matters.

I am thinking on what you said "if your speaker has reached its limit". My understanding was that manufacturers would like to bring their speakers for the low frequencies close to distortion to claim lower frequency responses.

 

[alaios]

Boosting bass will boost volume.

When you listen quietly, then you can boost a lot before your speakers complain.

When you listen super loud, then you're already close to the speakers' limits. Boosting bass by just a little while listening at that volume, may already push the speakers beyond what they can do.

Max 80db SPL at 2 meters. Not sure if this is considered loud

 

[alaios]

If you want more bass I think it is smarter to reduce the mid-treble. It does the same thing without any risk of clipping and obviates the need for negative gain before the EQ is applied.

That is what I was expecting from the EQ at wiim to do actually. But no they are boosting bass.

 

[Keith_W]

That is what I was expecting from the EQ at wiim to do actually. But no they are boosting bass.

As mentioned earlier, a bass boost is the same as a mid/treble cut. Whether it is a "boost" or not depends on what volume you set it to. Most speakers can be equalized to a perfectly flat frequency response, you just sacrifice a lot of volume. With the Polks I linked to earlier, you can see that the reference volume is 85dB, and at 20Hz it is 50dB. If you wanted to, you could cut 35dB and have a perfectly flat frequency response at 50dB. But then it becomes so soft that it is unusable.

Of course, that is an extreme scenario, I only mentioned it to illustrate my point. If your speakers are compromised, you can choose what you want to compromise. You can have something in the middle - a flatter frequency response at the expense of volume and increased distortion. Or you could have more volume and little bass, with what bass there is suffering distortion. Or you could go all the way and have a flat frequency response with hardly any volume. How much you need to compromise depends on you and your speakers.