Humps at 43Hz, 90Hz, and 110Hz

[The Computer Audiophile]

Hi Guys - I'm moving my new speakers around before a rep from Wilson arrives to complete the setup and did some measurements. I have elevated humps at 43Hz, 90Hz, and 110Hz.

 

I looked at some bass traps like these with a range limiter and they look pretty cool. https://www.gikacoustics.com/product/gik-acoustics-tri-trap/

 

Does anyone have suggestions how to tame these humps?

 

I'll do much more thorough measurements once the speakers are in their final places but want to do a bit of research beforehand. 

[rando]

This is based on head level measurements in listening chair or a few places in the room? 

 

Such as desk chair or the most natural place to stand.  Places that could conceivably be of secondary concern or prove insightful toward refining primary listening position.  

 

I'm sure you'll get plenty of experienced people offering solutions.  Best of luck getting everything sorted painlessly.

[The Computer Audiophile]

1 minute ago, rando said:

This is based on head level measurements in listening chair or a few places in the room? 

 

Such as desk chair or the most natural place to stand.  Places that could conceivably be of secondary concern or prove insightful toward refining primary listening position.  

 

I'm sure you'll get plenty of experienced people offering solutions.  Best of luck getting everything sorted painlessly.

Just took a few measurements with microphone places at ear level on listening chair. 

[rando]

Mind you I'm not conferring any expertise in this area on myself. 

 

Do you think there is any potential, is this extremely unusual, investigating elsewhere?  Through conversation on pyramid roofed studios and other atypical spaces (DAW' large home listening room had a 9' wall length difference the long way and roughly half that on the shorter front and back walls) it is hard to imagine some reinforcing measurements weren't collected to produce admirable results.

[Blake]

I was going to purchase the GIK Tri Traps, but the GIK consultant told me to go with the GIK Soffit Bass Traps instead.  He said they were much more effective than the Tri Traps.

 

The Soffit Traps work very nicely for me.

 

[rickca]

2 hours ago, The Computer Audiophile said:

Does anyone have suggestions how to tame these humps?

Now you got Fergie playing nonstop in my head.

[esldude]

What did you use to get the measurements?  As in which software.  And could you show at least the lowest 300 hz.  Maybe using REW or something similar.   And remind us of your room dimensions.  I remember you ad the sloping ceiling.   And how big are the humps?

 

Moving the speakers and/or yourself around is the first step.  

[The Computer Audiophile]

2 minutes ago, esldude said:

What did you use to get the measurements?  As in which software.  And could you show at least the lowest 300 hz.  Maybe using REW or something similar.   And remind us of your room dimensions.  I remember you ad the sloping ceiling.   And how big are the humps?

 

Moving the speakers and/or yourself around is the first step.  

I used REW.

 

I just ordered some of these ATS Acoustics Corner Bass Traps on the suggestion of @mitchco - https://www.atsacoustics.com/corner-bass-trap-b.html

 

Here's a screenshot of 10-200 with 1/12 smoothing

 

 

[The Computer Audiophile]

Playing around in Roon with the EQ can work some magic but there's no free lunch. 

 

[esldude]

15 minutes ago, The Computer Audiophile said:

I used REW.

 

I just ordered some of these ATS Acoustics Corner Bass Traps on the suggestion of @mitchco - https://www.atsacoustics.com/corner-bass-trap-b.html

 

Here's a screenshot of 10-200 with 1/12 smoothing

 

 

 

 

So something I wondered.  Your peaks are more like 43 or 44 hz and 88 hz.  I would think they are related.  Maybe by a room dimension around 12.5 or so feet.  

[The Computer Audiophile]

1 minute ago, esldude said:

 

 

So something I wondered.  Your peaks are more like 43 or 44 hz and 88 hz.  I would think they are related.  Maybe by a room dimension around 12.5 or so feet.  

13.8 feet wide

25.8 long

9 feet high

[The Computer Audiophile]

 

 

 

 

 

[barrows]

I cannot see the numbers on the response plot...  At those low frequencies normal physical bass traps may not be enough, but I would wait until your Wilson set up guy is around...

At RMAF one year we had a bad room mode at around 80 hz or so (like +10 dB or so).  We actually used a Synergistic Black Box which lowered it by about 6 dB, which was enough to accommodate music which had energy at that frequency-amazing little device really...  We just used a single one, but more can be applied.

[esldude]

I'd think it is related to the length mostly.  I'd try moving them 2 ft forward or backward.  2ft forward if you are less than 6.5 feet from the rear wall.  Of course I don't know where you have them and that may not be practical.  Before moving them I'd shoot tones at 44 hz and 88 hz through them, and go walk around the speakers.  You'll likely be able to find zones where the tones are louder vs softer.  If you can find one where both tones are softer, then put the speakers there.  In this case, if it is mostly the length mode, the left and right position is going to be less critical on these two humps.  

 

Of course those aren't easy to move speakers.  Even if you don't move them, shoot the tones thru them and walk around to see where peaks and dips are.  You may have the double whammy of speakers in a hot zone for those frequencies and your LP in a hot point for those.  So you might benefit some to move your LP to a place where there isn't a peak in the problem frequencies of 88 and 44 hz. 

[The Computer Audiophile]

2 minutes ago, esldude said:

I'd think it is related to the length mostly.  I'd try moving them 2 ft forward or backward.  2ft forward if you are less than 6.5 feet from the rear wall.  Of course I don't know where you have them and that may not be practical.  Before moving them I'd shoot tones at 44 hz and 88 hz through them, and go walk around the speakers.  You'll likely be able to find zones where the tones are louder vs softer.  If you can find one where both tones are softer, then put the speakers there.  In this case, if it is mostly the length mode, the left and right position is going to be less critical on these two humps.  

 

Of course those aren't easy to move speakers.  Even if you don't move them, shoot the tones thru them and walk around to see where peaks and dips are.  You may have the double whammy of speakers in a hot zone for those frequencies and your LP in a hot point for those.  So you might benefit some to move your LP to a place where there isn't a peak in the problem frequencies of 88 and 44 hz. 

Thanks a ton Dennis!

[RickyV]

Frequencies under 200 Hz are difficult to measure in a normal room because off all the reflections. Even Nearfield measurements, say 50cm from the woofer cone are not very trustworthy.

Even in a room like this where I did my final measurements of my speakers, every thing under 100Hz is difficult.

 

If you measure several times see if you get the same plot more or less. If you do that over the whole spectrum you can see where it starts to get unstable.

 

[semente]

39 minutes ago, The Computer Audiophile said:

I used REW.

 

I just ordered some of these ATS Acoustics Corner Bass Traps on the suggestion of @mitchco - https://www.atsacoustics.com/corner-bass-trap-b.html

 

Here's a screenshot of 10-200 with 1/12 smoothing

 

 

 

Could you re-plot this with the "standard" 50dB-wide vertical scale?

[The Computer Audiophile]

10 minutes ago, semente said:

 

Could you re-plot this with the "standard" 50dB-wide vertical scale?

Like this?

 

[semente]

1 hour ago, The Computer Audiophile said:

Like this?

 

 

That's perfect, thanks.

If the speakers aren't too difficult to slide around I would follow @esldude suggestion and measure the speakers in a slightly forward, a slightly backward and a slightly closer to each other position, move the listening spot back and forth for each speaker position and also try lowering or raising the mic by some 4 or 5 inches, just to get a feel of the room interference. I prefer to do this with pink noise but sweeps will work too.

I have found that a simple EQ'ing/bringing down the peaks will produce good results, a bit like looking at a rocky beach in low tide; suddenly there's life and detail and colour in the bass.

[sandyk]

3 hours ago, barrows said:

I cannot see the numbers on the response plot.

 Hi Barrows

 Click on the image a couple of times and you should get a full screen image with the numbers clearly visible.

Regards

Alex

[STC]

@The Computer Audiophile For LF, also consider speaker to speaker distance and floor reflection. Measure both speakers simultaneously and it is not critical that they must be measured at ear level as the sound wave length is long to be significantly different from a single point and at ear(s) level. 

[tmtomh]

I've just finished (mostly) initial setup of a new listening space, and I would concur with those who say it's very difficult to use acoustic treatments on bass frequencies below about 150Hz. For the 43 and 90Hz humps I think you have to set your expectations relatively low in terms of taming them. For the 110Hz hump it's more feasible but still difficult.

 

I would concerting with the recommendation for the GIK soffit traps - they're more effective than the tri/corner traps simply because they have a lot more depth across a larger surface area - and depth (plus some air gap between the trap and the wall if possible) is pretty much the only thing that matters - the deeper/thicker the trap, the better the absorption of low frequencies.

 

The good news is that even though it's nearly impossible to achieve full absorption of bass reflections, the thicker solutions will still provide some absorption, and even if you can get a hump to go from, say, +20dB to +17dB, that's a real difference and a noticeable improvement.

 

Finally, one free and easy way to smooth out lower-bass response is counter-intuitive: move the speakers closer to the front wall. The shorter the distance, the higher the "1/4 wave" frequency - in other words, with speakers closer to the front wall, the most problematic frequency is higher, and therefore easier to treat with absorptive panels behind the speakers (this is why some placement guides recommend putting the speakers either as close as possible to the front wall, or else at least 3 feet out).

[Allan F]

10 hours ago, The Computer Audiophile said:

Hi Guys - I'm moving my new speakers around before a rep from Wilson arrives to complete the setup and did some measurements. I have elevated humps at 43Hz, 90Hz, and 110Hz.

 

I looked at some bass traps like these with a range limiter and they look pretty cool. https://www.gikacoustics.com/product/gik-acoustics-tri-trap/

 

Does anyone have suggestions how to tame these humps?

 

I'll do much more thorough measurements once the speakers are in their final places but want to do a bit of research beforehand. 

 

I would certainly expect the Wilson rep to be the  best person to offer recommendations, including room treatment,  to optimize the speakers in your room.

[Solstice380]

It will be good to have the traps to work with when the Wilson setup person is there. Do you know who is coming out?

[barrows]

3 hours ago, Solstice380 said:

It will be good to have the traps to work with when the Wilson setup person is there. Do you know who is coming out?

I would expect it to be Peter McGrath, as Chris is now a "pretty important" person in the Industry based on site popularity.  Who would've have known!