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Dry bass

Keith_W

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Jun 26, 2016
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For some time now, I have a bass problem. The bass does not sound impactful or physical, it's just ... there. For context, I have 4x 12" Rythmik sub drivers built into two subwoofers, crossed over at 80Hz, with DSP provided by Acourate. If I turn the subs louder, it sounds unbalanced and there is way too much bass (but strangely, it still seems to lack punch). I have visited friends with systems that sound balanced, but the bass has a physical quality, it seems to actually pressurize your lungs and vibrate your body.

I am wondering whether it is because my bass is too dry. My Rythmik subs are servo controlled, so they certainly have the potential to create dry bass. Take a look at this:

ADCreHdopH8ZQjoPy1CGF7PjNDplurE6Q0Pp5ScplTG8m46F6AeiqU3RZVGl2T8pTUZvIkAPcC9dwegE_bRevcB_bQQTGVfofuYy0J7-XP_KiPnpw9GZURj91-t0iiabezZKEQJjBqqqLqnscz5C-rULpn7How=w1920-h1080-s-no-gm


Notice how the RT60 falls below the target at 110Hz. I am aware that RT60 has no meaning for small room acoustics because even large "small rooms" like mine (measures 6m x 7m x 3m, or approx 20' x 23' x 10') do not produce reverberant fields.

I am not sure where the blame lies. For those systems that have impactful bass, they were all using much bigger subwoofers than mine - one guy has four 15" subs, and another has two subwoofers, with each subwoofer containing 3x 12" drivers. So I am not sure whether my result is due to using smaller subs, or whether it is because my bass is too dry.

Is anybody aware of a way to wetten the bass whilst leaving the rest of the FR untouched? I know there is a procedure in Acourate for generating a VBA, and I am wondering if I could modify that to create reverb instead of cancelling bass.
 
Can you show the impulse/step response and the spectrogram also?
 
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I kinda know what you mean. I experienced the same thing with a pair of Infinity Kappa 7.2i's. They delivered punchy bass. Physical. Those have a 10" woofer. Then I replaced them with Kappa 8.2i's. Those have 12" woofers. They lacked the punch from the smaller speakers. It came down to fiddling a bit more with my Dirac house curve and getting the right slope on the correction curve. I've spent quite some time wondering about this. It couldn't be right that the bigger brother didn't have the punch as the smalle siblings.

Your curve looks way too flat for meaningful physical bass IMO. I would try low-passing your subs in small increments a bit higher up the frequency and see if the punch doesn't show itself when your curve is raising towards 20 Hz.
I have mine approx +8 dB from 20-20.000. Come to think of it, I could probably live with a couple of dB more but it's quite nice balanced as it is.
 
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My first impression of that graph is that you have way too little bass full stop. You seem to have EQed out all the room gain maybe? Personally my room curve climbs from 200Hz, and is 12dB up by 40Hz. That’s for 75dB average listening levels. A lot of the “punch” is in the 80-150 range, so just turning up the gain on your subs wouldn’t help. Just a hot take, maybe I have misunderstood the graph,
 
You could try to make this target curve:
1702186239293.png
 
Sorry that is an older target curve. This is a newer one, showing a bit more bass dialled in, but with the same dry bass:

1702187476027.png


Impulse and Step response:

1702187661807.png


1702187687085.png


I can't show a spectrogram at the moment because that would involve taking a measurement with REW, and I can't take measurements right now because I have loaned my interface to a friend. But I do have a waterfall display taken with an older target curve back when I was experimenting with a VBA:

1702188550203.png


@Hayabusa I have tried a target curve similar to what you suggested in the past, in fact I have tried extreme target curves with a +10dB bass shelf (!!!). It sounded bassy and bloated and it still lacked impact. It is the same result if I simply increase the volume of the sub. I do not think the volume of the bass is the problem, I think it is something else. I have a lot of difficulty understanding why I can have too much bass and still lack bass impact at the same time, and I have come up with the following theories:

- perhaps the bass is too dry?
- perhaps the large-ish size of the room means I have less pressure mode?
- perhaps the subwoofer drivers are too small?

Given that theories (2) and (3) are not easily testable (it would involve a tonne of work moving my speakers to another room, and it would involve $$$ to buy another sub), I have decided to investigate whether dry bass can cause this problem of "lack of impact".
 
Sorry that is an older target curve. This is a newer one, showing a bit more bass dialled in, but with the same dry bass:

View attachment 332972

Impulse and Step response:

View attachment 332973

View attachment 332974

I can't show a spectrogram at the moment because that would involve taking a measurement with REW, and I can't take measurements right now because I have loaned my interface to a friend. But I do have a waterfall display taken with an older target curve back when I was experimenting with a VBA:

View attachment 332975

@Hayabusa I have tried a target curve similar to what you suggested in the past, in fact I have tried extreme target curves with a +10dB bass shelf (!!!). It sounded bassy and bloated and it still lacked impact. It is the same result if I simply increase the volume of the sub. I do not think the volume of the bass is the problem, I think it is something else. I have a lot of difficulty understanding why I can have too much bass and still lack bass impact at the same time, and I have come up with the following theories:

- perhaps the bass is too dry?
- perhaps the large-ish size of the room means I have less pressure mode?
- perhaps the subwoofer drivers are too small?

Given that theories (2) and (3) are not easily testable (it would involve a tonne of work moving my speakers to another room, and it would involve $$$ to buy another sub), I have decided to investigate whether dry bass can cause this problem of "lack of impact".
Thats kind of peak at 50Hz and then a lot less from 20-40Hz.. I would at least make that more following the suggested target curve
 
Sorry that is an older target curve. This is a newer one, showing a bit more bass dialled in, but with the same dry bass:

View attachment 332972
Better, but I would still suggest you have a lot of work to do on FR before you start chasing other issues.
  • That's a huge drop from 50Hz down to 40Hz, in my system I would have that +20dB level continue to 30Hz before rolling off
  • It's hard to be exact without some averaging being applied, but you have a broad peak from 250Hz to 350Hz, and narrow peak at 500Hz, both of 6dB to 10dB magnitude.
  • You have a rising response from 6KHz up to 19KHz of 6dB magnitude
Psychoacoustics isn't intuitive at all. Any one of the issues above could be causing your brain to hear "dry bass"
 
Sorry that is an older target curve. This is a newer one, showing a bit more bass dialled in, but with the same dry bass:

View attachment 332972

Impulse and Step response:

View attachment 332973

View attachment 332974

I can't show a spectrogram at the moment because that would involve taking a measurement with REW, and I can't take measurements right now because I have loaned my interface to a friend. But I do have a waterfall display taken with an older target curve back when I was experimenting with a VBA:

View attachment 332975

@Hayabusa I have tried a target curve similar to what you suggested in the past, in fact I have tried extreme target curves with a +10dB bass shelf (!!!). It sounded bassy and bloated and it still lacked impact. It is the same result if I simply increase the volume of the sub. I do not think the volume of the bass is the problem, I think it is something else. I have a lot of difficulty understanding why I can have too much bass and still lack bass impact at the same time, and I have come up with the following theories:

- perhaps the bass is too dry?
- perhaps the large-ish size of the room means I have less pressure mode?
- perhaps the subwoofer drivers are too small?

Given that theories (2) and (3) are not easily testable (it would involve a tonne of work moving my speakers to another room, and it would involve $$$ to buy another sub), I have decided to investigate whether dry bass can cause this problem of "lack of impact".
Can you please post the mdat in a zip file?
 
Yeah, I didn't show you this:

1702189560556.png


The reason I didn't post it is because it's a sim (predicted response after corrections). I have the real measurement somewhere but I can't find it. And as mentioned, I have to wait a couple of weeks before my interface returns and I can measure it again.
 
Are there any places in your room where you get that physical bass you want?

Measure at that place. Compare to your main listening pos.
 
Are there any places in your room where you get that physical bass you want?

Measure at that place. Compare to your main listening pos.

Hmm, I just tried it. There are parts of the room where there is one note bass, parts where there is suckout, but nowhere does it feel "physical". Not even standing next to the subwoofer.

Viscreal bass is above the subwoofer range. Not feeling the bass is more 80-300Hz.

Now THAT is an interesting insight! I have never heard of this, nor have I performed any experiments like this. Are you suggesting that a shelf from 80-300Hz might fix the problem?
 
Do you have any bass trap or sound insulation??
Which amplification is been used??
 
Hmm, I just tried it. There are parts of the room where there is one note bass, parts where there is suckout, but nowhere does it feel "physical". Not even standing next to the subwoofer.



Now THAT is an interesting insight! I have never heard of this, nor have I performed any experiments like this. Are you suggesting that a shelf from 80-300Hz might fix the problem?
Rather from 20. And experiment with the upper shelf as too high makes the sound "boxy" IME.
 
For some time now, I have a bass problem. The bass does not sound impactful or physical, it's just ... there. For context, I have 4x 12" Rythmik sub drivers built into two subwoofers, crossed over at 80Hz, with DSP provided by Acourate. If I turn the subs louder, it sounds unbalanced and there is way too much bass (but strangely, it still seems to lack punch). I have visited friends with systems that sound balanced, but the bass has a physical quality, it seems to actually pressurize your lungs and vibrate your body.

I am wondering whether it is because my bass is too dry. My Rythmik subs are servo controlled, so they certainly have the potential to create dry bass. Take a look at this:

ADCreHdopH8ZQjoPy1CGF7PjNDplurE6Q0Pp5ScplTG8m46F6AeiqU3RZVGl2T8pTUZvIkAPcC9dwegE_bRevcB_bQQTGVfofuYy0J7-XP_KiPnpw9GZURj91-t0iiabezZKEQJjBqqqLqnscz5C-rULpn7How=w1920-h1080-s-no-gm


Notice how the RT60 falls below the target at 110Hz. I am aware that RT60 has no meaning for small room acoustics because even large "small rooms" like mine (measures 6m x 7m x 3m, or approx 20' x 23' x 10') do not produce reverberant fields.

I am not sure where the blame lies. For those systems that have impactful bass, they were all using much bigger subwoofers than mine - one guy has four 15" subs, and another has two subwoofers, with each subwoofer containing 3x 12" drivers. So I am not sure whether my result is due to using smaller subs, or whether it is because my bass is too dry.

Is anybody aware of a way to wetten the bass whilst leaving the rest of the FR untouched? I know there is a procedure in Acourate for generating a VBA, and I am wondering if I could modify that to create reverb instead of cancelling bass.

I had the same issue and here is how I solved it:

I was also playing around with Dirac's target curve but that never really helped
So I leave Dirac with the flat target curve and I apply post-EQ to shape the bass (and the treble) to my taste

In order to make the bass punchy and more meaty I am applying so-called resonant filters (basically a low-shelf where the Q value is above 1.0)

It looks like this:

1702194694333.png


I used a combination of two shelf filters here - you need to experiment to get the results you need

The point of resonant filters is that there is an undershoot and an overshoot part of the resulting curve (the amount of which is controlled with the Q value) that will actually 'slow down' the bass, making it sound more punchy.
nb. this is exactly the effect that vintage EQs like Pultec are using to achieve their legendary bass sound (see 'Pultec-punch')

On another note: as you see above, there is nothing boosted above 100Hz (or even lower). This is done on purpose - at least in my two rooms I noticed that boosting in the region of 100-200Hz will make the bass too 'heavy', killing the dynamics
 
I had the same issue and here is how I solved it:

I was also playing around with Dirac's target curve but that never really helped
So I leave Dirac with the flat target curve and I apply post-EQ to shape the bass (and the treble) to my taste

In order to make the bass punchy and more meaty I am applying so-called resonant filters (basically a low-shelf where the Q value is above 1.0)

It looks like this:

View attachment 332984

I used a combination of two shelf filters here - you need to experiment to get the results you need

The point of resonant filters is that there is an undershoot and an overshoot part of the resulting curve (the amount of which is controlled with the Q value) that will actually 'slow down' the bass, making it sound more punchy.
nb. this is exactly the effect that vintage EQs like Pultec are using to achieve their legendary bass sound (see 'Pultec-punch')

On another note: as you see above, there is nothing boosted above 100Hz (or even lower). This is done on purpose - at least in my two rooms I noticed that boosting in the region of 100-200Hz will make the bass too 'heavy', killing the dynamics
Strange that you couldn't get the same result with EQ in Dirac which essentially is the same.
 
Strange that you couldn't get the same result with EQ in Dirac which essentially is the same.
Well, my big problem with Dirac's concept is that it is not real-time
You set your whatever target curve, save, play, listen then loop

I prefer doing the final correction in real-time so I can listen to what I am doing on-the-fly
That (to me at least) leads to a much better result
 
Do you have any bass trap or sound insulation??
Which amplification is been used??

I don't have bass traps. The reason the bass is so dry is because I have a massive window and an adjoining dining room. It allows the bass to "escape" from the main listening room either outside to the backyard, or into the dining room where it won't reflect back. I am using a pair of Rythmik plate amps, 800W Class D. Each amp drives two sub drivers.

I had the same issue and here is how I solved it:

I was also playing around with Dirac's target curve but that never really helped
So I leave Dirac with the flat target curve and I apply post-EQ to shape the bass (and the treble) to my taste

In order to make the bass punchy and more meaty I am applying so-called resonant filters (basically a low-shelf where the Q value is above 1.0)

It looks like this:

View attachment 332984

I used a combination of two shelf filters here - you need to experiment to get the results you need

The point of resonant filters is that there is an undershoot and an overshoot part of the resulting curve (the amount of which is controlled with the Q value) that will actually 'slow down' the bass, making it sound more punchy.
nb. this is exactly the effect that vintage EQs like Pultec are using to achieve their legendary bass sound (see 'Pultec-punch')

On another note: as you see above, there is nothing boosted above 100Hz (or even lower). This is done on purpose - at least in my two rooms I noticed that boosting in the region of 100-200Hz will make the bass too 'heavy', killing the dynamics

THANK YOU! I did a search for the "Pultec-punch" and came across a few resources, including this thread on ASR where you contributed. I am trying to wrap my head around exactly what it is and how it works. I think the easiest way to try it out is to download that Puigtec plugin before I try to simulate it in Acourate. Please give me a day or two to digest this information because it seems confusing and counterintuitive to me.
 

Also have a look at the whole thread.
 
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