Is there a minimum threshold for room treatment?

[csepulv]

Buy a book on the acoustic like the Rod Gervais book or find on the net the Ethan Winer book.

Acoustics/Treatment Reference Guide - LOOK HERE! - Gearspace.com

If you're looking for the quickest way to get started, I suggest checking out 1c, 2b, and 2a. These briefly and simply cover the basics (and have lots

gearspace.com

On a forum that boasts of science, it's misery on the acoustic side.
It's better

Thanks for the references. the gearspace link is a good starting point

 

[Hipper]

Have you considered adding some scatter plates? it's so great seeing someone who went all the way and have the results to show it.

I did buy a panel with a scatter plate but found the same problem I had with their quadratic diffusors in that I could hear it. I was able to remove it from the panel and use it as a normal absorber.

GIK have also developed something called the Flexrange which seems to improve increase bass absorption and reduce that of the higher frequencies:

https://gikacoustics.co.uk/product/gik-acoustics-soffit-bass-trap/

 

[Hipper]

Hello
Do you have measurements before and after the acoustic treatment?
Can you put the REW .mdat file?
It is simple curiosity to see what marks the TR (Topt, T20, T30), Waterfall, Spectrogram, etc.

Can you comment on your acoustic treatment?

Written with translator

Greetings

Mdat files as requested.

I'll comment later.

 

[Hipper]

Hello

Can you comment on your acoustic treatment?

Written with translator

Greetings

I'm not sure what comments you want but I'll give a bit of my history.

I tried some speakers that sounded good at a dealer's house but in my room I couldn't get a good sound out of them. My dealer suggested room treatment. I found Auralex foam and used that. It sounded better but I didn't know much then and discovered that this foam only absorbs down to 125Hz. Further investigations brought me to GIK and I bought some bass traps and panels. Much better! I had also discovered digital equalisers and bought a Behringer DEQ2496 and learnt how to use it. More improvement. However I wanted better still so got REW and measured (I measured before but just with test tones and an SPL meter). This led to me finally invested in all the bass traps you see in the photo (post 12).

All this room treatment plus EQ with the Behringer, along with careful positioning of speakers and chair and a reduction in ambient noise with extra glazing has got me where I want to be. I appreciate not everyone would like my sound but why should I care - I'm happy!

I appreciate I'm lucky that I have a dedicated room. I hear no reason to change anything until my speakers fail.

 

[Willem]

I sympathize with csepulv's desire to maintain the esthetic quality of the room. By the look of the reponse graph the response with Dirac does not look too bad at all. The biggest issues seem to be at the lower frequencies, and I think a second subwoofer will be quite beneficial for that. See here for inspiration: http://archimago.blogspot.com/2020/05/musings-measurements-subwoofers-to.html From your graph it seems your current subwoofer may not be that large, and if so you might get a bigger one and put it in one corner and use your existing sub to fill in.

 

[csepulv]

I sympathize with csepulv's desire to maintain the esthetic quality of the room. By the look of the reponse graph the response with Dirac does not look too bad at all. The biggest issues seem to be at the lower frequencies, and I think a second subwoofer will be quite beneficial for that. See here for inspiration: http://archimago.blogspot.com/2020/05/musings-measurements-subwoofers-to.html From your graph it seems your current subwoofer may not be that large, and if so you might get a bigger one and put it in one corner and use your existing sub to fill in.

Yeah, my single sub is not very powerful. It is a Paradigm Cinema Sub from an older 5.1 set. I've been considering replacing it to get lower response. Maybe I will buy two subs. I've been eyeing Rythmic L12, SVS SB1000 and Monoprice Monolith THX 10". I like the Rythmic and the SVS, as they have smaller footprints. (Again shared room, I can't put larger box subs). But I read very good things about the Monoprice.

 

[csepulv]

I've discovered reflections might be a bigger problem than I first thought. I ran this stereo imaging test through my system

All the positions localize very well, except the Off Stage Right. I hear that coming from the two places in red below

I am going to try shifting the sofa a bit further back or forward, to see if it helps. Otherwise I will look at room treatment that might help.

Since my LP is approximately inline with the corner area, my guess was that is contributing to or causing the reflection and hearing off-stage-right, on my left side. Or is this a coincidence?

 

[hemiutut]

I'm not sure what comments you want but I'll give a bit of my history.

I tried some speakers that sounded good at a dealer's house but in my room I couldn't get a good sound out of them. My dealer suggested room treatment. I found Auralex foam and used that. It sounded better but I didn't know much then and discovered that this foam only absorbs down to 125Hz. Further investigations brought me to GIK and I bought some bass traps and panels. Much better! I had also discovered digital equalisers and bought a Behringer DEQ2496 and learnt how to use it. More improvement. However I wanted better still so got REW and measured (I measured before but just with test tones and an SPL meter). This led to me finally invested in all the bass traps you see in the photo (post 12).

All this room treatment plus EQ with the Behringer, along with careful positioning of speakers and chair and a reduction in ambient noise with extra glazing has got me where I want to be. I appreciate not everyone would like my sound but why should I care - I'm happy!

I appreciate I'm lucky that I have a dedicated room. I hear no reason to change anything until my speakers fail.

Thanks Hipper for the deference in answering and for the .mdat file.
Of course, the acoustic treatment is noticeable and not a little,
looking at the waterfall, TR, etc, etc.
I have seen the .mdat file and I see that in the frequency response (All SPL) there is a strong drop from 1.5-2 Khz.
Is that answer an average of the 2 Front or is it that I had put the microphone a little low and therefore the lack of treble?

Greetings and enjoy the team room

 

[abdo123]

I did buy a panel with a scatter plate but found the same problem I had with their quadratic diffusors in that I could hear it. I was able to remove it from the panel and use it as a normal absorber.

GIK have also developed something called the Flexrange which seems to improve increase bass absorption and reduce that of the higher frequencies:

https://gikacoustics.co.uk/product/gik-acoustics-soffit-bass-trap/

You could hear what exactly?

 

[Tim Link]

Blimey. A pair of headphones would have been cheaper

Headphones would be awesome if it weren't for the lack of any HRTF effects. I've tried Greisinger's method of simulating HRTF on headphones. I got it to work somewhat, but you can't move your head or the image moves with it, which destroys the illusion.

 

[Hipper]

Thanks Hipper for the deference in answering and for the .mdat file.
Of course, the acoustic treatment is noticeable and not a little,
looking at the waterfall, TR, etc, etc.
I have seen the .mdat file and I see that in the frequency response (All SPL) there is a strong drop from 1.5-2 Khz.
Is that answer an average of the 2 Front or is it that I had put the microphone a little low and therefore the lack of treble?

Greetings and enjoy the team room

The measurements were made using just the left speaker with the microphone at ear height pointing at the speaker. The right speaker was almost the same. That 'strong drop from 1.5-2 Khz' is in both the no treatment and the full treatment measurements. I don't know why.

After adding all the treatment I used EQ to finish, including filling in the dip at 50Hz and adjusting other areas to my taste. As I'm 68 years old I've got hearing deficiencies in the high frequencies so have EQ'd a bit for that and also to add percussion. I haven't got any measurements as it is now.

 

[Hipper]

You could hear what exactly?

I could hear sound coming from where the scatter plate/diffusor was. I was sitting too close to them for them to work properly.

 

[Hipper]

I've discovered reflections might be a bigger problem than I first thought. I ran this stereo imaging test through my system

All the positions localize very well, except the Off Stage Right. I hear that coming from the two places in red below
View attachment 164944

I am going to try shifting the sofa a bit further back or forward, to see if it helps. Otherwise I will look at room treatment that might help.

Since my LP is approximately inline with the corner area, my guess was that is contributing to or causing the reflection and hearing off-stage-right, on my left side. Or is this a coincidence?

It could be that you are getting what's called first reflections from the right and secondary reflections from about the left corner, meaning that the sound has reflected off the right wall, then again off the left wall and to your ear.

The standard way of finding where reflections will come from is 'the mirror test'. You sit in your listening position and get a second person to move a mirror on the right wall until you can see your speaker drivers. That is the first reflection point. Another way would be to draw an accurate plan of your room with speaker and ear positions and draw a line from the driver to your ear so that the angle it hits and reflects off the wall is the same. Here's one I did in 2013:

You can then look at reflections off any wall from any speaker. Remember you might also hear reflections from the left speaker coming off the right wall to your right ear.

Wall reflections are a contentious issue. I've tried to cancel all mine and find it gives me a precise image with clear instruments and vocals, but that image remains only between the speakers (unless there is some peculiarity in the recording). Others like the wider image that reflections might give. Psychoacoustics (how the ear and brain combine to allow you to 'hear' things) comes into play here too.

Moving your ears (sofa) will not only effect reflections but also the bass. Play a bassy song, or perhaps a single bass tone, and walk round your room. You should notice that the tone sounds different in different places. Not only that but if you move your head to the floor or to the ceiling it will sound different there too. That leads to the important conclusion that positioning of ears and speakers is a way of changing and perhaps improving how bass sounds. Of course you may be restricted on positioning because of your domestic circumstances but it may help. If you can add a corner bass trap here and there that would help too. Then what can't be corrected by that can be altered with subs or DSP/EQ. Here's a test tone CD that is useful:

http://realtraps.com/test-cd.htm

Then look at the higher frequencies/reflections. Reflections can be altered perhaps by speaker positioning and/or toe-in, stopped by panels (art panels maybe). You can't stop reflections with DSP/EQ but you can use it as a kind of tone control adjusting large parts of the frequency range to your taste.

The ultimate solution is not found in measurements - these are just tools - but in what sounds good to you.

 

[csepulv]

It could be that you are getting what's called first reflections from the right and secondary reflections from about the left corner, meaning that the sound has reflected off the right wall, then again off the left wall and to your ear.

The standard way of finding where reflections will come from is 'the mirror test'. You sit in your listening position and get a second person to move a mirror on the right wall until you can see your speaker drivers. That is the first reflection point. Another way would be to draw an accurate plan of your room with speaker and ear positions and draw a line from the driver to your ear so that the angle it hits and reflects off the wall is the same. Here's one I did in 2013:

View attachment 165065

You can then look at reflections off any wall from any speaker. Remember you might also hear reflections from the left speaker coming off the right wall to your right ear.

Wall reflections are a contentious issue. I've tried to cancel all mine and find it gives me a precise image with clear instruments and vocals, but that image remains only between the speakers (unless there is some peculiarity in the recording). Others like the wider image that reflections might give. Psychoacoustics (how the ear and brain combine to allow you to 'hear' things) comes into play here too.

Moving your ears (sofa) will not only effect reflections but also the bass. Play a bassy song, or perhaps a single bass tone, and walk round your room. You should notice that the tone sounds different in different places. Not only that but if you move your head to the floor or to the ceiling it will sound different there too. That leads to the important conclusion that positioning of ears and speakers is a way of changing and perhaps improving how bass sounds. Of course you may be restricted on positioning because of your domestic circumstances but it may help. If you can add a corner bass trap here and there that would help too. Then what can't be corrected by that can be altered with subs or DSP/EQ. Here's a test tone CD that is useful:

http://realtraps.com/test-cd.htm

Then look at the higher frequencies/reflections. Reflections can be altered perhaps by speaker positioning and/or toe-in, stopped by panels (art panels maybe). You can't stop reflections with DSP/EQ but you can use it as a kind of tone control adjusting large parts of the frequency range to your taste.

The ultimate solution is not found in measurements - these are just tools - but in what sounds good to you.

Thanks for the details on the mirror test. I will try that -- should be a fun exercise and educational.

For subwoofer placement, I had done a few different things. I had placed the sub at the listening position and played sub cal in REW and walked around the room, to get an idea of possible sub locations. Once I narrowed that down, I put the sub in those positions and would both listen and do measurements. I settled on "top right" (from diagram) room location for the sub.

Reflections and decay time seem to be something for me to contend with, both looking at measurements and listening in the room.

On the stereo imaging, I was able to move the sofa a 8-12" forward and that removed the left "echo" and I hear all the positions in the test imaging well.

 

[GalZohar]

Isn't the purpose of the limited band absorption for those who cover most of the room with absorption to handle low frequencies but don't want to absorb too much high frequency energy? I suppose those wouldn't be relevant for those looking for minimalistic treatment?

And I still can't find a clear answer to whether minimal treatment (covering only a small % of the room in strategic points) can provide a noticeable benefit that justifies the cost. Most information I find suggests that for optimal results, much of the room has to be covered, but optimal results are not obtainable for me both due to room: it's living room, kitchen and dining room in 1 large space. Also due to budget: The whole system is less than 5000$ and sounds nice to me, so not really willing to spend thousands more on treatment, so this would be a no-go unless I can get a noticeable improvement with a not-so-expensive budget expense and no serious damage to the looks and function of the room (so no throwing panels randomly and especially not just in the middle of the space).

 

[hemiutut]

The measurements were made using just the left speaker with the microphone at ear height pointing at the speaker. The right speaker was almost the same. That 'strong drop from 1.5-2 Khz' is in both the no treatment and the full treatment measurements. I don't know why.

After adding all the treatment I used EQ to finish, including filling in the dip at 50Hz and adjusting other areas to my taste. As I'm 68 years old I've got hearing deficiencies in the high frequencies so have EQ'd a bit for that and also to add percussion. I haven't got any measurements as it is now.

When you have time, measure again but the mic pointing to the ceiling with the calibration file at 90º

That sudden drop that we discussed is not normal.

Be careful with going up a lot of db in that 50 Hz dip that you comment.

 

[Doodski]

unless I can get a noticeable improvement with a not-so-expensive budget expense

The first time I treated a room I used 2-6'x3'x~3" (2m x 1m x ~8cm) sound absorbing office divider panels as a experiment and they worked wonderfully. They are available in different colors and can be found as used fairly easily if you just want to test drive sound absorbing panels. I placed them against the wall directly behind my head and the imaging opened up and everything was better. No more ringing in the room and dampened the reflections to where it was not hollow sounding.

 

[Vuki]

Minimum would be to get RT60 bellow 0.5 seconds above 125hz.

 

[csepulv]

I was able to borrow a second subwoofer. I went through setting up per @abdo123's instructions in

DDRC-24 - Dirac Live on a budget?

No. you can purchase a Dirac license directly, and also get a Dirac bass control license, but then you need a DAC with as many outputs / channels as your inputs. I'm not sure if two stereo DACs would work. but DDRC-24 would work wonderfully for a 2.2 or a 2.1 setup.

www.audiosciencereview.com

(Thanks @abdo123 )

While neither sub has very good low frequency response, the second sub does help mitigate the null around 60hz.

I can't hear meaningful difference with the two subs vs the one sub (maybe some volume).

Low frequency decay isn't great.

And I can hear some reflections/echoes at times. (Ringing?) There are some nulls below 500hz. But the overall result isn't too bad.

But I think I've gone as far as I can with DSP. I also think 2 subs, in my case, might not much of an audible improvement. A better sub and some room treatment might be needed, if I want audible improvement. I think I would need to pursue that before a second sub.

I will probably look at bass traps in the corners and finish furnishing the room. (This whole effort is part of a room swap in my house, which is till in progress). Then re-measure and see if I do anything else.

 

[GalZohar]

Minimum would be to get RT60 bellow 0.5 seconds above 125hz.

I see several graphs in REW related to RT60. Which one should I be looking at?

And why is that really a "minimum"? If we reduce it from 1 to 0.6 would it be an insignificant improvement?

Minimum for me is something that would make a noticeable improvement. Not necessary something that will reach optimal or even great results. Sometimes "good" is good enough when the alternative is "mediocre"...