Keep bass traps or send them back (with measurements)? Your advice needed!

[Satyadhara]

Hi everyone, I recently got some bass traps from Perfect Acoustics - these ones in 104x40x40cm: https://perfect-acoustic.com/termek/acoustical-sound-panels/
Now I did a series of measurements with and without them, and as far as I can say, they don't make that much difference. Below are some screenshots from REW. I'm kindly asking for your feedback on the measurements. Should I keep the bass traps or send them back?


Frequency response comparisons:

RT60 comparisons for left speaker (RTA):

RT60 comparisons for right speaker (RTA):

RT60 comparisons for left speaker (Sweep):

RT60 comparisons for right speaker (Sweep):

 

[raindance]

The spectrogram in REW will give you more info than RT60. RT60 is next to useless in small rooms, it's only useful in large spaces like concert halls or public theaters. Where are the bass traps placed?

 

[abdo123]

The spectrogram in REW will give you more info than RT60. RT60 is next to useless in small rooms, it's only useful in large spaces like concert halls or public theaters. Where are the bass traps placed?

it's not useless, we're not conducting a scientific study here so absolute values are not necessary. for comparision purposes RT60 is just fine.

 

[abdo123]

@Satyadhara

I think you're not quite comprehending what acoustic treatment does exactly, it only reduces the decay time of target frequencies. We can see very clearly in your RT60 graphs that they're working as intended.

Room treatment generally will not change the overall response significantly unless significant portions of the walls are covered (more than 20% of the entire surface area of the room). The in-room response is a physical property of the room that is a result of the shape of the room and the location of the speakers and listening position.

If you want to actually change the room response without extensively covering the entire walls with treatment, then you have to target very early reflections with the room treatment that occur in 5ms to 30ms after the incidence of direct sound.

Useful reading here: https://en.wikipedia.org/wiki/Precedence_effect

and here: http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

In your current situation you're simply making sure that frequencies decay the way artist intends, frequencies no longer linger more than they're supposed to, Which in theory should be audibly beneficial.

 

[abdo123]

I took a further look at your graph, and there is clearly more energy in the 80Hz-300Hz region with the bass traps installed. Also less troughs and wigilness in the area.

 

[raindance]

I took a further look at your graph, and there is clearly more energy in the 80Hz-300Hz region with the bass traps installed. Also less troughs and wigilness in the area.

This is what I typically find, in the mid and upper bass area it gets a little more easy to distinguish between notes. Like most acoustic treatment, it impacts "intelligibility" within each frequency range by reducing hang time. I use quotes because we're not talking about speech .

I still feel the spectrogram shows the effects more readily for the average person.

 

[Satyadhara]

Thank you very much for your replies - and yes, you're absolutely right in saying that I'm not (yet) quite comprehending how exactly all of this works. I'm learning day by day. I sent my REW measurements to several providers of acoustic panels asking them how to improve room acoustics and they all told me "get bass traps and maybe a broadband absorber for the ceiling" - so I did that. I honestly thought the frequency response would improve more, but hey - now I know more. As I definitely don't want to cover 20% or more of my room with absorbers, I'll keep it at that and see if I can do something about the peaks at 30Hz and 50Hz with DSP (I use Roon).

 

[ppataki]

@Satyadhara You can also use the Overlay mode to view these measurements on top of each other so it becomes very easy to see the differences
For example you can turn on Topt and display one measurement with and without the traps

My personal experience is that it is also very useful to calculate the T60M graphs since they are more accurate and they can go down to 20Hz
Here is how you can do that:

I have used HOFA Natural Bass Traps that did reduce ringing in lower frequencies (you can search for that post here in ASR)
But then I have replaced them with 10cm thick Caruso Isobonds (the ones with 10.000 Pa*s/m² airflow resistance) and they are even better at reducing ringing + they have a higher WAF since they are only 10cm thick. I have covered them with white acoustic textile and put them on my front and side walls. I can very highly recommend them

 

[Satyadhara]

And here are the spectrograms:

Left speaker:

Right speaker:

 

[Frgirard]

The spectrogram in REW will give you more info than RT60. RT60 is next to useless in small rooms, it's only useful in large spaces like concert halls or public theaters. Where are the bass traps placed?

REW doesn't measure the RT60. RT60 is the name of the window. Read the REW help.

 

[abdo123]

And here are the spectrograms:

Left speaker:

View attachment 172840

View attachment 172841

Right speaker:

View attachment 172842

View attachment 172843

definitely less ringing from 80Hz all the way up to 1KHz.

 

[Frgirard]

And here are the spectrograms:

Left speaker:

View attachment 172840

View attachment 172841

Right speaker:

View attachment 172842

View attachment 172843

Assuming you did the measurement without move the mic, you can read the effect of the bass trap. it works fine in the low mid and a little under 100 Hz.
Only you can listen and tell if YES or NOT .

 

[ppataki]

If it helps I am attaching my measurements below

This is with the Caruso Isobonds (highlighted) vs without any treatment:

And this is Caruso Isobond (highlighted) vs the HOFA Bass Traps:

 

[Roland99]

@Satyadhara
Thank for so much for sharing your experience with these products.
I am also interested in buying bass traps from Perfect Acoustics.

Could you may give an update about your current acoustics? Are you finally happy with these products?

 

[ozzy9832001]

How many traps did you buy?

People underestimate how many are actually required to make a noticeable difference. I have over 20 panels and 8 "corner" traps that are 18" deep and I still could use more to really get things going.