Masurements after initial treatment, pls help me improve and fix issues!

#1

Hi all just wanted to share with you the on going Acoustic Treatment for a small home studio space roughly 4.3m deep * 3.1m wide * 2.8m tall as you can see in the photos there is a false ceiling around the inner walls to accommodate duct work and lighting.

Speakers are 0.8m apart, sitting close to the front glazings and distance between tweeter and woofer measuring 1.15m off ground. I’ve tested a few settings and found this to be the best sounding with no treatment. Note, for the untreated measurements the the speakers and mic position were different, I made some amendments to speaker arrangements to avoid certain modes which seemed better.

As of now I’ve treated all corners with 600*600 polyester fibre wool columns / soffits - 30kg /m3 & based on various researched papers I’ve estimated it’s air flow resistance to be 2-3k Pa.S / sqm. Next phase would to treat the first reflection points side walls , ceiling and rear wall.

As you can see in the REW measurements there is an substantial improvement compared to the non treated room where everything is more smoothed out. From 20hz to 500hz there are still dips here and there but only 3db difference from 80db excluding 300hz area. Huge dip at 800hz and massive dip at 10-12khz, The room definitely sounds much better now compared to prior of treatment, the low end is much tighter, I’ve also noticed a very strong resonance in the high freq when I’m inside the room I assume it is the untreated ceilings.

Would appreciate it if Stuart & everyone else could provide some comments and feedbacks, perhaps pointing out major fallbacks and next steps and strategies.

Many thanks for your help!

#2

Hi jazztronaut!

Your room seems to be healthy. The measurements show very good results IMHO. Decays look fine. There are some issues in the waterfall, but my bet is that there are electrical noise issues into the microphone or any part of the audio chain.

The huge dip around 10k is because you don't have your mic at exactly the same distance from each speaker. It's clearly showed in the impulse response graph.

There's also a dip at 800 hz give or take, which I think it's caused by desk reflections, but I'm not sure. I would have to pay a better look into the impulse response.

What else to do to improve even more your acoustics is something I'm not completely sure. But what I can tell you is that you seem to be in a good sounding room, with some room for improvement, but with not too many issues as it is now.

Let's see what do other members suggest!

Best regards,

Eric

#3

ericwisgikl wrote:Hi jazztronaut!

Your room seems to be healthy. The measurements show very good results IMHO. Decays look fine. There are some issues in the waterfall, but my bet is that there are electrical noise issues into the microphone or any part of the audio chain.

The huge dip around 10k is because you don't have your mic at exactly the same distance from each speaker. It's clearly showed in the impulse response graph.

There's also a dip at 800 hz give or take, which I think it's caused by desk reflections, but I'm not sure. I would have to pay a better look into the impulse response.

What else to do to improve even more your acoustics is something I'm not completely sure. But what I can tell you is that you seem to be in a good sounding room, with some room for improvement, but with not too many issues as it is now.

Let's see what do other members suggest!

Best regards,

Eric

Hi Eric, thank you for your response. I'm happy to hear that the room does not have too much problems, I can also hear its much better compared to previous home studios I've had. I would like to improve it as much as possible.

Currently there are no treatment on the early reflection points, should I do something about that? Was planing to make 600 deep panels on the ceiling around the listening position. For the walls 300mm deep panels. Note there is a desk / equipment rack on the left wall does it make any sense to treat behind the furniture?

I've also attached a video where I've noticed a ringing flutter echo with strong resonance that seems to be coming from the ceiling, is that something I should be concerned about?

Appreciate it if anyone else could also chime in !

#4

Hi jazztronaut,

In order to see what first reflection points you need to treat, you could pay a look at your impulse response and apply the "string trick", described by Stuart in the following link: viewtopic.php?f=14&t=208&p=1373&#p1373

That way you could find that maybe you don't need treatment into some places you thought you needed, and you need where you didn't think you do.

In your measurements I can tell you there are some reflections from your desk. My bet is that they are guilty about your dips in the mid range. Then, near -20 db, there are some spikes, which are early reflections. Even they're 20 db quieter than direct sound, I'm sure they screw your response up in some degree.

Also, when you apply more treatment, you have to pay attention at your RT60 graphs, in order to remain balanced all over the spectrum, the most you can. If you end up over treated at some areas, you then have to think how to get some liveness back. Maybe with some slats over your current treatment, or with some plastic foil.

About those flutter echoes from your ceiling, first you have to figure out if they come from the interaction between floor and ceiling, or from the interaction between higher side little walls, which have no treatment at all at the moment. Then, some absorbers at the right spot will tame those flutters off.

Cheers,

Eric

#5

ericwisgikl wrote:Hi jazztronaut,

In order to see what first reflection points you need to treat, you could pay a look at your impulse response and apply the "string trick", described by Stuart in the following link: viewtopic.php?f=14&t=208&p=1373&#p1373

That way you could find that maybe you don't need treatment into some places you thought you needed, and you need where you didn't think you do.

In your measurements I can tell you there are some reflections from your desk. My bet is that they are guilty about your dips in the mid range. Then, near -20 db, there are some spikes, which are early reflections. Even they're 20 db quieter than direct sound, I'm sure they screw your response up in some degree.

Also, when you apply more treatment, you have to pay attention at your RT60 graphs, in order to remain balanced all over the spectrum, the most you can. If you end up over treated at some areas, you then have to think how to get some liveness back. Maybe with some slats over your current treatment, or with some plastic foil.

About those flutter echoes from your ceiling, first you have to figure out if they come from the interaction between floor and ceiling, or from the interaction between higher side little walls, which have no treatment at all at the moment. Then, some absorbers at the right spot will tame those flutters off.

Cheers,

Eric

I have finally completed installing all the treatments this time it was ceiling clouds 1.2m*1.8m*0.6m + Rear wall and some side wall panels. I ended up covering everything with a thin plastic film as I noticed a lot of dust in the room. It was A LOT of work but turned out looking pretty good with the new fabric.

I did some initial measurements and wanted to get some opinions from you guys !

Based on the measurements the low end had improved but not a huge difference. The decay time have reduced quite a bit, but I do not notice the room sounding very dead. Should I try to liven it with 1D diffusors or perforated panels?

I noticed there is a huge dip at 1.5k not sure the reason which was not there in the last measurement. Could this be due to comb filtering?

I have attached the measurement files and some images for your reference. Would appreciate any help ! Not too sure what I'm looking at to be honest.

Many Thanks!

#6

Hi jazztronaut,

I don't see the .mdat file into the attachments.

Cheers,

Eric

#7

ericwisgikl wrote:Hi jazztronaut,

I don't see the .mdat file into the attachments.

Cheers,

Eric

apologies, here it is ! :-)

#8

Hi jazztronaut,

Looking at your measurements, I can tell that your low end shows some improvement. The new treatment helped tackling some modes. Also the low-mid range looks better.

About the dip around 1.5 khz, 3.5, and so on, it's comb filter. Perhaps due to reflections from your desk, I'm not shure. It's possible it was always there but masked by other issues. You could use the 'string trick' to figure out where those reflections come from.

Last thing I could say is that your RT60 now is into the dead ballpark. Maybe you could put some slats over your treatment, out from the reflection free zone, in order to live up your room a bit in mids and highs.

Cheers,

Eric

#9

thank you appreciate it!

Soundman2020 - Studio Design Forum