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Do I really need a sub? (including REW measurements)

ninetylol

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Hello people,

I ordered a KEF Kube 12B to supplement my Elac DBR62. The sub is actually overkill for my small listening space (about 5x4,5x2,53m).

After measuring (crossover 90Hz with HPF to speakers), level matching and removing room resonances (following measurements include resonances so are without EQ), i really cant tell much of a difference with sub or without (I can switch it on and off quickly with WiiM amp). My listening volume is mostly 60-65db, so maybe because of Fletcher–Munson curves thats the culprit?

I will add some RTA measurements i did a few days ago, where you can see the sub is actually just filling a bit of a null at about 58Hz. Rest of the spectrum is within 3db the same till about 28Hz. Actually i dont know why the DBR62 create so much low frequency extension in my room. Anyway heres the REW results.

Screenshot 2024-01-29 174253.png

Screenshot 2024-01-29 174221.png



Would be happy for any type of feedback!
 
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ninetylol

ninetylol

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Heres the result with PEQed sub to take out room resonances. vs speaker only
Screenshot 2024-01-29 174358.png
 
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bodhi

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You basically said it. You don't hear much of a difference and the measurements show a reason. The sub doesn't do anything in the frequency range it would be needed.

Have you tested with material that certainly has lower bass content? In my desktop setup the speakers go flat to 33Hz and it's hard to tell sub is present until there is something for it to do. When there is, it is certainly noticeable.

In my other setup the speakers play only to about 45Hz and still on one occasion I had the 2.0 preset selected and it took me a while to notice when playing music, even though I have a lot more powerful sub setup in similar kind of room as you have.
 

LSPhil

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Congratulations on the excellent components, KEF Kube 12B and Elac DBR62. To achieve better bass reproduction, I recommend bypassing the high-pass filter at 90 Hz and letting the speakers operate at full range. Connect the subwoofer and experiment with the crossover frequency and level until you are satisfied with the result. The measured outcome should lead to a +10 dB adjustment on the subwoofer. In enclosed spaces, there are no waves in the bass range, only maxima and minima. For this reason, you might be missing at least 6 dB in the bass range. It's important to note that cancellations, or minima, should not be filled in.
 

Purité Audio

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ninetylol

ninetylol

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You basically said it. You don't hear much of a difference and the measurements show a reason. The sub doesn't do anything in the frequency range it would be needed.

Have you tested with material that certainly has lower bass content? In my desktop setup the speakers go flat to 33Hz and it's hard to tell sub is present until there is something for it to do. When there is, it is certainly noticeable.

In my other setup the speakers play only to about 45Hz and still on one occasion I had the 2.0 preset selected and it took me a while to notice when playing music, even though I have a lot more powerful sub setup in similar kind of room as you have.
Thanks, Yeah in really heavy Bass content (deadmau5, Skeler) I hear a bit of difference, but still not a night and day difference. Im wondering why my DBR62 play so low in my room, maybe thats why I dont noticed such a big difference.
Congratulations on the excellent components, KEF Kube 12B and Elac DBR62. To achieve better bass reproduction, I recommend bypassing the high-pass filter at 90 Hz and letting the speakers operate at full range. Connect the subwoofer and experiment with the crossover frequency and level until you are satisfied with the result. The measured outcome should lead to a +10 dB adjustment on the subwoofer. In enclosed spaces, there are no waves in the bass range, only maxima and minima. For this reason, you might be missing at least 6 dB in the bass range. It's important to note that cancellations, or minima, should not be filled in.
I can of course turn the sub up (its playing at 9 o clock volume atm, which results in a more or less neutral harman response. If I turn it up more it starts to Sound too bassy and muddy. I cant turn off the hpf to speakers, but dont think thats the problem. I did not try to eq the null of course.
What’s the cause of the large null, have you tried REW’s ‘Room sim’ feature?
Keith
Its a room problem. I cant fix it without changing the whole listening setup. Small changes in MLP or speakers just changed the null Hz but didnt remove it. My room is too complicated for the room sim feature.
 
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ninetylol

ninetylol

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Have you tried different subwoofer placements? Or is this what constitutes the "whole listening setup" change you can't do?
I did all positions which were possible with no change. (just worse)
 

LSPhil

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Then close the BR ports on the satellites. You can do this with socks but they have to be clean.
If you're still patient, take a close measurement of the bass membranes of the subwoofer and the satellites.
 

bodhi

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Try the subwoofer kick test with and without the sub. For the last two the difference should be pretty drastic.

 

Digital_Thor

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Earl Geddes had some good points regarding this:

1. Let the mains run full range, preferably closed box, so that there is minimum phase issues

2. Place the subwoofers away from the mains, and in a way so that they excite as many different modes in the room

3. Let the subwoofers overlap the mains, as high as possible, without letting them be located by ear - one subwoofer can both differentiate by phase, gain and cross-over frequency, from the other subwoofers and the mains - it's the combined response that should be linear and smooth.

4. Adjust the subwoofers, so that the combined response - mains included - has a minimum amount of suck-outs - then EQ what is too much - since you can't successfully EQ a suck-out.

It can be tedious, but it's doable. Sometimes you just have to reset it all and start over, til it works.
 

DVDdoug

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Just a note - For surround-sound movies a sub is required for the "point one" LFE channel. The other channels contain "regular bass" which can optionally be re-routed to the sub via "bass management" in an AVR. But it doesn't work the other way around and the LFE is not included in the stereo mix.
 

cicastol

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My listening space is near your's for dimensions, adding a sub (Ayra Po 10" RCF) to the Elac DBR62 was like day e night for low end extension.
 
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ninetylol

ninetylol

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My listening space is near your's for dimensions, adding a sub (Ayra Po 10" RCF) to the Elac DBR62 was like day e night for low end extension.
Interesting. Thats how it should be I guess, but my measurements are not lying, retested today. Maybe my room excites some modes below 55hz and thats why theres no big upgrade for me.
 

jhwalker

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Interesting. Thats how it should be I guess, but my measurements are not lying, retested today. Maybe my room excites some modes below 55hz and thats why theres no big upgrade for me.
Well, the other thing is that your sub(s) rolloff drastically below 30Hz. That's not really all that low, and many speakers by themselves are in that same range, performance-wise For comparison, my subs are -6db at 10Hz.

But if you're happy with that level of performance, you're right - you're not getting much benefit other than filling in that MASSIVE suckout.
 

DJBonoBobo

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I don’t really understand. I see a sub filling a huge grand canyon of a dip perfectly. Isn't this what it should do?
 
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ninetylol

ninetylol

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I don’t really understand. I see a sub filling a huge grand canyon of a dip perfectly. Isn't this what it should do?
Our psychoaccoustic hearing fills out this dip too (more or less), extension is quite more important.
 

DJBonoBobo

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Our psychoaccoustic hearing fills out this dip too (more or less), extension is quite more important.
Ok, but i am still not sure what your question is. Do you wonder about the drop below 30Hz? I guess this could be back wall SBIR. I had the same and killed it with 2 PSI AVAAs. It worked, but i am not sure how audible this even is. If interested, see: https://www.audiosciencereview.com/...n-a-small-room-subs-ma1-absorbers-avaa.27288/
Some are suggesting measuring deep bass in lower height, because it seems the body recognizes low frequencies with stomach/legs more than with ears, but i don't know more about this.
 

radix

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Have you tried adjusting the sub phase or inverting it? You can also try elevating the sub or pointing it towards a wall or sideways. It's all geometry at those frequencies.

The sub is doing it's job for the 60 Hz null. It's the 24 Hz one to tackle.
 
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