Improving room acoustics

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Improving room acoustics

Post by ambientgeneration »

Hi all

I write my music in the box room of my modest house.

Recently I’ve been putting a lot of effort into trying to improve the neutrality of the sound I hear in this room.

To do this I have used IK ARC 3 to measure the room and then painstakingly changed just one thing at a time and remeasured. What I have found has surprised me.

In order of the amount of difference it has made -
1. The monitor speakers
2. The position of the speakers in the room
3. The amount and position of any acoustic treatment.

In fact the acoustic treatment has made little difference and bizzarely it has usually made things worse.

I have a selection of acoustic absorbers to use by different manufacturers and up to 4 inches thick.

Without any treatment the room is badly echoey, with treatment at the key reflection points the echo is well under control, but it makes little difference to the graphs ARC is showing.

I think my conclusion is that the kind of absorbers a home hobbyist like me uses only tackle the high frequencies > 500Hz and these frankly are not the problem. Anything less than that though needs a big room and seriously expensive bass traps and even these made only a modest difference - the only real solution is an acoustic engineer and a builder.

Which leads me to conclude we should all spend our money on reasonable monitor speakers, software such as ARC and a small amount of acoustic absorbers only. We should also get some decent open flat headphones with some EQ software such as Sonarworks and something like Waves Abbey Road headphone plugin as another listening source, and if we really think we’ve got a good track then go and finish mixing it in a proper studio.

Would be very interested in peoples thoughts as to whether they agree / disagree.

Thanks
Matt
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Re: Improving room acoustics

Post by resistorman »

I think decent room treatment, small high quality monitors close to you situated where they sound best in the room and a couple pairs of high quality headphones you know and trust is a perfectly acceptable workflow.
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Re: Improving room acoustics

Post by RichardT »

What materials are your absorbers made from? If the answer is acoustic foam then that is likely to be the problem. It won't do much for the low frequencies.

A really small room will always be a compromise, but you could try building some rockwool bass traps yourself to see what their effect is. I have a very narrow room myself, though it's quite long, and rockwool traps have made a quite amazing difference.
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Re: Improving room acoustics

Post by ambientgeneration »

RichardT - yes my absorbers are all acoustic foam ...

I'll look up how to build rockwool bass traps - do these get positioned in the corners rather than reflection points?
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Re: Improving room acoustics

Post by blinddrew »

I'm not familiar with IK ARC or the graphs it creates, but when using REW on my room it took a bit of time to properly understand what I was seeing on the graphs.
For example, the overall frequency response plot post-treatment seemed to be much more spikey than it was before. However when you looked at the time domain it became apparent that the frequency response was being smoothed out by the long reverberation tails. Remove those tails and it sounds better but looks worse.
Interpreting acoustic measurements, especially in small rooms, can be fraught with mis-direction.
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Re: Improving room acoustics

Post by orange »

blinddrew wrote: Sun Sep 05, 2021 11:19 am I'm not familiar with IK ARC or the graphs it creates, but when using REW on my room it took a bit of time to properly understand what I was seeing on the graphs.

yes, and I don't think that IK ARC is the correct tool for this anyway. I realise IKM describe this as "room analysis software and correction plug-in" and "3D room analysis" but from what I can tell (and I own it!) it's really only doing a frequency sweep and applying an eq correction curve. .....I think. It doesn't actually present any kind of full analysis. So not suitable at all for working out what is actually going on.

REW is a totally different, and better, beast
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Re: Improving room acoustics

Post by RichardT »

ambientgeneration wrote: Sun Sep 05, 2021 11:13 am RichardT - yes my absorbers are all acoustic foam ...

I'll look up how to build rockwool bass traps - do these get positioned in the corners rather than reflection points?

For a quick method have a look at this

https://www.youtube.com/watch?v=IPU6_1prLyA

In a small room I would use rockwool traps both at the relection points and also in corners or close to other parts of the wall. That way you'll get the most benefit. Rockwool traps do some good pretty much wherever you put them, but always make sure there is a space between the trap and the wall / ceiling as right next to a solid surface the air does not move enough. In my experience, trial and error in your room will be the only way to find the best locations. And it's usually the case of the more the merrier! Bear in mind that significant trapping will affect the frequency response of the room - it will create a broad reduction in HF, and you'll need either to get used to that, or apply some EQ to the sound. I use Sonarworks reference to compensate for that - others prefer not to.

I haven't used REW or any analysis tool, but others have. You'll be able to hear for yourself when the sound is improved - it's not subtle!
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Re: Improving room acoustics

Post by ambientgeneration »

So I downloaded REW and with no external SPL meter (I guessed at 75db (!)) and using my ARC2 microphone with no calibration file I "measured" my room with no treatment, wall treatment but without my 2 bass traps, and then with everything in. I can't really read what it's telling me - except that it is pretty obvious now the treatment is making a big difference. Just need to read up on how to use REW now!! Thanks everyone.
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Re: Improving room acoustics

Post by Sam Spoons »

I'd say forget about measurement software in a small room and judge any changes by ear using a few familiar, well recorded/mixed reference tracks. The goal IMO is to control reverberation above about 250-500 Hz and to make whatever reduction you can in room mode resonances below that. The latter is always a compromise and a combination of bass trapping and monitor/listening position placement is required to achieve the best result.
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