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Will acoustic foam panels help?

iGPR3

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Jun 14, 2024
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At high volumes, my JBL LSR305 monitors sound super harsh, (at low volumes it’s fine, but I’m guessing reflections are just more present at high volumes?) and I reckon it’s from room reflections. How much of a difference would acoustic foam panels make and where would be the best place to put them? And would my 10” subs under my desk also need acoustic foam along the wall?

Main setup:
image.jpg
Behind setup:
image.jpg
 
Reflections are present at all volumes.

The reason your speakers sound harsh at high volume is likely due to equal loudness contours and possibly woofer limiting.

Woofer limiting can be fixed by high-passing the speakers and you can compensate for equal loudness contours using DSP.

Room treatment like acoustic panels can reduce decay times, giving your system a tight, dry, focused sound (if done right).

Room treatment is rarely the right tool for changing the tonal characteristics, and should ideally be applied only after assessing the acoustics using a measurement microphone.
 
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Reflections absolutely can lead to harshness. Especially those arriving early from certain angles but even late ones.

Foam isn't a good absorber. Something that absorbs evenly at least down to the Schroeder frequency is the best. Don't use thin absorbers as they will only work well on higher frequencies.
 
Given the placement of your monitor's and listening position I don’t think acoustic treatment of any sort will help much, if that was my only option in the room for such a setup I’d be inclined to rotate the desk 45° so it’s sitting diagonally across the corner, as the monitors would have more room to radiate reflections into the room.
 
Given the placement of your monitor's and listening position I don’t think acoustic treatment of any sort will help much, if that was my only option in the room for such a setup I’d be inclined to rotate the desk 45° so it’s sitting diagonally across the corner, as the monitors would have more room to radiate reflections into the room.
My desk is screwed into the wall to give me as much room as I can fit in this tiny corner, so I can't rotate it. Probably just gonna DSP it and try to get the harshness out that way if panels won't make a difference.
 
Reflections absolutely can lead to harshness. Especially those arriving early from certain angles but even late ones.

Foam isn't a good absorber. Something that absorbs evenly at least down to the Schroeder frequency is the best. Don't use thin absorbers as they will only work well on higher frequencies.
If I did get panels instead of EQing out that harshness, would it be enough to stick them along the back and left walls and not behind me? And what cheap panels would you recommend instead of foam?
 
Reflections are present at all volumes.

The reason your speakers sound harsh at high volume is likely due to equal loudness contours and possibly woofer limiting.

Woofer limiting can be fixed by high-passing the speakers and you can compensate for equal loudness contours using DSP.

Room treatment like acoustic panels can reduce decay times, giving your system a tight, dry, focused sound (if done right).

Room treatment is rarely the right tool for changing the tonal characteristics, and should ideally be applied only after assessing the acoustics using a measurement microphone.
My 10" subs aren't in a proper box yet, I'll likely finish the box in a couple weeks. Also gonna get a DSP at some point for low + high passing those subs and my monitors.

As much as I'd like a measurement mic, it's too much to justify the price. Whereas acoustic panels are cheap enough that I can grab a set and just see what they're like
 
If I did get panels instead of EQing out that harshness, would it be enough to stick them along the back and left walls and not behind me? And what cheap panels would you recommend instead of foam?
The side walls, computer on the right and ceiling above the speakers are the worst areas. Remove the computer at least. It's also difficult when the proximity to the surfaces is so close.
The time domain will not follow the frequency, so EQ for specular energy is not a good solution. It will get less worse with EQ, but something will also get worse since the time domain doesn't follow.
For budget solution, you are better off building your own absorbers. Minimum 7-8 cm thickness.
 
You need to use a mirror to find the exact areas to place absorbers, but these are approximately the places where you need some good absorption.
areas of treatment.jpg
 
The side walls, computer on the right and ceiling above the speakers are the worst areas. Remove the computer at least. It's also difficult when the proximity to the surfaces is so close.
The time domain will not follow the frequency, so EQ for specular energy is not a good solution. It will get less worse with EQ, but something will also get worse since the time domain doesn't follow.
For budget solution, you are better off building your own absorbers. Minimum 7-8 cm thickness.
I might move the PC off of my desk, but it gets super dusty on the floor and it’s a nightmare to get to any cables. I’ll try sort something out once I get my subs installed. Only worry on the floor is my hard drives might have issues being right next to 2 huge magnets.
 
At high volumes, my JBL LSR305 monitors sound super harsh, (at low volumes it’s fine, but I’m guessing reflections are just more present at high volumes?) and I reckon it’s from room reflections. How much of a difference would acoustic foam panels make and where would be the best place to put them? And would my 10” subs under my desk also need acoustic foam along the wall?

Main setup:
View attachment 394128
Behind setup:
View attachment 394129
My workplace is very similar to yours, 1.6m wide, walls to the right and left.
I had tried many active and passive monitors up to €1000, including the JBLs, and with all of them that had a kind of horn attachment (which was almost all of them), I had the same problem as you. When I turned the volume up, it became unpleasantly harsh and hard. I had never experienced that from any normal HiFi speaker.
Massive use of acoustic materials brought almost no improvement. The only thing that would make a difference would be a volume-dependent DSP curve.

I then happened to come across a pair of cheap Elac Carina BS243.4s and they were immediately perfect. Even at volumes where I have problems with the neighbors and despite the very detailed mid and high frequency range.

By the way, a Mac Mini (M2 Pro) would permanently improve your space problem with the computer and access to all cables would also be very easy.
 
My workplace is very similar to yours, 1.6m wide, walls to the right and left.
I had tried many active and passive monitors up to €1000, including the JBLs, and with all of them that had a kind of horn attachment (which was almost all of them), I had the same problem as you. When I turned the volume up, it became unpleasantly harsh and hard. I had never experienced that from any normal HiFi speaker.
Massive use of acoustic materials brought almost no improvement. The only thing that would make a difference would be a volume-dependent DSP curve.

I then happened to come across a pair of cheap Elac Carina BS243.4s and they were immediately perfect. Even at volumes where I have problems with the neighbors and despite the very detailed mid and high frequency range.

By the way, a Mac Mini (M2 Pro) would permanently improve your space problem with the computer and access to all cables would also be very easy.
Would it really need to be volume dependent? Not sure if the DSP I'm gonna get even has that capability, it's the t.racks DSP 4x4 mini. If you have any other recommendations under £130 that would be great.

Sadly I can't switch to apple because I do a lot of gaming (you cant see it in the pics but I do VR sim racing, and macOS won't be able to run my games). I doubt even putting my PC on the floor would make much difference anyways with my space so cramped.
 
Would it really need to be volume dependent? Not sure if the DSP I'm gonna get even has that capability, it's the t.racks DSP 4x4 mini. If you have any other recommendations under £130 that would be great.

Sadly I can't switch to apple because I do a lot of gaming (you cant see it in the pics but I do VR sim racing, and macOS won't be able to run my games). I doubt even putting my PC on the floor would make much difference anyways with my space so cramped.
As you said yourself, it gets worse as the volume increases.
Before you buy something, test with EQ settings to see if it works at all volumes with the same settings, or if you need to adjust the EQ as volume increases. This will give you an answer quickly and easily.
There is a thread here with possible EQ software. A trial version would be enough to try out for now.
EQ Software for Windows, Linux, macOS, iOS/iPadOS and Android
 
Oh wow, I’ll have to look into that. I wanted a UMIK1 but didn’t think it was worth the price. Thanks
Umik-1 has enabled the best ever sound upgrade I've had. Controlling the base in a room is an utterly transformative experience and the mic makes this all possible.
 
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