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Box room problem or benefit?

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Re: Box room problem or benefit?

Postby Sam Spoons » Thu Feb 06, 2020 10:58 pm

I put ten panels into my 4 x 4 m room. It's great for listening/mixing but still not dry enough for recording unless everything is fairly close miked. two 1200mm square panels will have made a difference but you need more, mirror points (there are at least four of those, side walls, back wall and ceiling. And probably behind the monitors. Then you need some additional bass trapping.

Rather than being despondent try recording some playback from the monitor speakers with a mic at the listening position then listen back with headphones so you can hear what improvement they are actually making. You made it work with duvets so you can make it work with 'proper' panels (and bear in mind that a double duvet is more than twice the size of each of your 1200mm2 panels).
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Re: Box room problem or benefit?

Postby Martin Walker » Fri Feb 07, 2020 10:59 pm

Sam Spoons wrote:I put ten panels into my 4 x 4 m room.

I've got eleven bass traps in my small studio, which made a big difference, but it's still not perfect by any means.

I found vertically straddling the front corners was most effective, then the same for the back corners, and then a ceiling cloud.

Add to that some lighter traps on the early reflection points, and I was mostly there.


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Re: Box room problem or benefit?

Postby Sam Spoons » Fri Feb 07, 2020 11:57 pm

Yup, that was the point I was trying to make :thumbup: I've just done some slightly more distant miking and have realised that, while my room is pretty good for listening it's not so good for tracking acoustic instruments without additional help.
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Re: Box room problem or benefit?

Postby Hugh Robjohns » Sat Feb 08, 2020 12:45 pm

Gmonics22 wrote:It's completely untreated and bare at the mo, and it has a pretty horrendous resonance around 130hz which basically makes my kicks sound like they're running through a very intense short delay & metallic reverb!

That description sounds like you have a lot of flutter echoes in the room, which is not entirely surprising if it is completely untreated. But it would be worthwhile also making sure that you don't have something resonating from the vibrations -- other equipment in the room, speaker stands, tables, light fittings, loose rack bolts... it's amazing what can be set off in sympathetic resonance!

I'm hoping some bass traps in the corners and panels on the walls will help, but don't really know where to start and don't want to shell out on heaps of stuff to get no results.

Yes it will help, obviously. I wouldn't worry about bass traps for the moment -- you can add those later if necessary. I'd start with some broadband absorber panels on the side mirror points, and on the front and back walls. Depending on whether the floor is carpeted or a hard surface, you might end up needing something on the ceiling too, but again, that can be added later.

The first step would be to deal with sidewall and front-back reflections to try and kill all those flutter echoes. Typically, I'd aim to cover maybe 25-30% of the bare wall surfaces with absorber panels. Two large panels wont be that effective I'm afraid. Even small rooms would usually need 6-10 panels.... Albeit usually 2x4ft ones rather than 4x4ft monsters.
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Re: Box room problem or benefit?

Postby CS70 » Sun Feb 09, 2020 1:12 pm

Gmonics22 wrote:Update:

So after lots of research I have constructed 2 broadband absorbers. 4' x 4' of 100mm RWA45 in wooden frames, with a breathable cotton covering. Experimented with placing them straddling the front wall corners (no difference) first reflection points (no difference) and back wall (no difference).

Feeling kind of defeated at this point. I wasn't expecting anything near a perfect room, but I have seen literally no improvement whatsoever. The honk is still overpowering everything. And now I have two giant turquoise monoliths mocking me while I cry at my desk, which now smells like a builders merchants. Time to give up or double down and make another 2? A happy accident at Travis Perkins gifted me another 4 slabs of Rockwool, which they don't want back. Little victories...

Flutter echos! I have my home setup in a small extension of the main living room (choose your partner wisely ;-) ) and the room originally suffered from them horribly. Still does in the "dining space" proper. If you clap your hand, you can really hear a short metallic echo which is unbearable if you have minimally trained ears (the rest of the gang here, of course, notices nothing and just thing it's the TV which is not that good to listen to :) ).

Luckily these echos aren't hard to defeat. They are usually quite high frequency so they dissipate quickly with the distance and easy to absorb if you understand where they come from. Duvet have probably failed you because, if your room is anything like mine, the echos occur with reflections between floor and ceiling as much (or more) than walls. You can experiment simply by walking around and clapping your hands - if the timbre of the echo stays pretty much similar, it's likely its main component is due to floor-ceiling, which keep the same distance from you as you walk (as opposite to the side walls, obviously).

In my room, the main issue is flat wooden flooring and a very reflective material that was used to finish the ceiling. Walls are drywall with insulation sandwiched between them and the outer wood shell (it's Norway, it's cold and there's lots of wood so houses are mostly in wood).

At my mixing station, I cured that issue primarily by hanging a large broadband absorber/almost bass trap (sourced from a cine-room shop) on the ceiling, leaving about 15cm of air. Of course broadband panels all around and I have a couple of large cylindrical bass traps behind the speakers.

it's far from perfect but the difference between where I sit and just a meter on the side (in the dining room proper) is like night and day when it comes to dryness. The metallic ringing disappeared entirely (as much as my ageing ears can tell of course :) ) and what I mix on speakers turns out to be generally fine without much effort (I usually compare at the proper studio and there's little tweaking to do be done, mostly).

In short : try to place one of the traps you've built over your seat (or a bit back).. if you have a couple friends you could ask them to just hold it there for you. Remember - not flush with the ceiling, but with good space between. Hopefully you should see a remarkable improvement.

It will most likely be that you *still* need the duvets (or the panels) on the walls and the back of the speakers. If you use duvets, once again not flush on the wall, but with a good space between them and the wall.

Best of luck!
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Re: Box room problem or benefit?

Postby Gmonics22 » Sun Feb 09, 2020 9:03 pm

Update:

Again, thanks to all for your suggestions and encouragement, you've really helped me keep the faith. Even though it's hard going I've found the enthusiasm to get to the stage of mixing a project today, which I haven't done in years!

A picture of where I'm at right now - can't work out how to embed it I'm afraid:

http://imgur.com/gallery/xAGZDEn

The whole setup is very temporary while I continue to experiment, but so far I've managed to get the troublesome 130hz and 200hz spikes down to within about +3-5db. Progress! As you can see I've bodged a ceiling cloud from 2 sofa cushions and a fleece blanket. This is going to be replaced with another 100mm Rockwool panel. At the moment the "air gap" is about 2ft... Once complete the side panels will be mounted with a 4inch gap, and the cloud a foot down.

Re the flutter echoes, this is more good information and something I'll be investigating. The floor is good thick carpet, but maybe some tasteful foam dotted around would be judicious. Luckily the colour scheme downstairs is a lot of charcoal grey...

Thanks folks :)
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Re: Box room problem or benefit?

Postby Martin Walker » Sun Feb 09, 2020 10:18 pm

So pleased to hear that you're moving forward - ceiling clouds can provide a surprising amount of acoustic improvement, basically because that replace an otherwise flat and totally reflective surface :thumbup:


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Re: Box room problem or benefit?

Postby Martin Walker » Sun Feb 09, 2020 10:24 pm

Gmonics22 wrote:A picture of where I'm at right now - can't work out how to embed it I'm afraid: http://imgur.com/gallery/xAGZDEn

1. Just right-click on that image in your link and select the Save image address option.

2. Now click on the Img (Insert image) option above your in-progress SOS Forum post and then paste this image address in between its two halves, and you'll get:

Image

(Love that temporary ceiling cloud :D 8-) :thumbup:


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Re: Box room problem or benefit?

Postby CS70 » Mon Feb 10, 2020 10:30 pm

Great to hear. Fun with the cloud but that's really the trick more often than not.

Another couple of easy interventions: I can't really see the orientation of the monitors, but reflections from the hardwood desk can bounce back directly to your ears - if you orient them slightly upwards it can help - and/or moving them forward on the desk. I get the control surface needs space but it may be a little too long for my tastes. You could have it on
side car. Basically you want the cone of sound to get clear of the desk front border as much as you can. Looks like you have space for stands and they also could help, but definitely more forward. You may find that in that position you need to position (or better, add to) the cloud a bit behind your seat to keep on absorbing the high frequencies before the hit the ceiling.

Also I am not sure if the whey protein bins are empty or full :-) - fill'em with sand if they aren't.

Putting a fluffy carpet under the desk and your chair can also help a little - while a carpet is usually too thin to do much for anything that very high frequencies, in conjunction with the ceiling absorbers can further limit echos.

That window on the back is not that good - it will reflect some energy directly onto you. A bit counter-intuitively, larger monitors would help as their mount tend to have a bit of play so they dissipate high freq which hits the back a bit in my experience (I got better sound when I switched from one to two 27 inches monitors :) ). Ideally, you would want to cover it with an absorber - whether or not is feasible for aesthetic reason (or just light) is another matter of course.

Good to see you're making progress.
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Postby DanDan » Mon Feb 10, 2020 11:39 pm

You appear to be applying solutions without knowing the cause of the symptoms, or perhaps even the symptoms themselves. Honks can have many causes, but my gut instantly says ceiling or desk of some kind.
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Re: Box room problem or benefit?

Postby Gmonics22 » Wed Feb 12, 2020 5:20 pm

CS70 wrote:I can't really see the orientation of the monitors, but reflections from the hardwood desk can bounce back directly to your ears - if you orient them slightly upwards it can help - and/or moving them forward on the desk.

You may find that in that position you need to position (or better, add to) the cloud a bit behind your seat to keep on absorbing the high frequencies before the hit the ceiling.

Also I am not sure if the whey protein bins are empty or full :-) - fill'em with sand if they aren't.

Putting a fluffy carpet under the desk and your chair can also help a little - while a carpet is usually too thin to do much for anything that very high frequencies, in conjunction with the ceiling absorbers can further limit echos.

That window on the back is not that good - it will reflect some energy directly onto you. A bit counter-intuitively, larger monitors would help as their mount tend to have a bit of play so they dissipate high freq which hits the back a bit in my experience (I got better sound when I switched from one to two 27 inches monitors :) ). Ideally, you would want to cover it with an absorber

Desk is 18" from the front wall, and 4ft x 2.5ft. This puts the speakers 4ft apart, and 4ft from my mixing spot. Said mixing spot is 3/8ths into the room. Have tried various configurations and this seems to be the best. Protein containers (must remove those labels!) are filled with sand so well damped, they are the perfect fit for the monitor bases and put them level with my ears too. I've thought of stands, but this would mean either putting them further back or wider, which would mess up my triangle or put my mixing position 1/4 or 1/2 into the room, which has proven worse.

Ceiling light is bang in the middle, which precludes extending the cloud further back.

Re the window, agree this is probably anothet issue, I'm planning on filling it with some less dense insulation which I have freely available.

This is all on the tightest budget as I've not long bought the house and am pretty stretched, so new monitors are out od the question right now... plus I'm on the party wall so not sure it would be a great idea so wind up the new neighbours just yet!

All your help is really appreciated. It does feel like I'm getting somewhere. Hopefully have it done and looking a bit more proper soon.

Thanks folks :)
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Re: Box room problem or benefit?

Postby Wonks » Wed Feb 12, 2020 5:39 pm

You could build a cloud with lights in it (often done) or one with a hole in it to dangle a light flex through (if that doesn't make the light too low).
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Re: Box room problem or benefit?

Postby CS70 » Wed Feb 12, 2020 6:54 pm

Gmonics22 wrote: I've thought of stands, but this would mean either putting them further back or wider, which would mess up my triangle or put my mixing position 1/4 or 1/2 into the room, which has proven worse.

For mixing, dry is far more important than the triangle.. it matters little that your head is at the triangle apex, if where you ears are the reflections are mangling the sound coming out of the speakers.

A desk's surface is very near to the sound source and usually very reflective, so the directional frequencies which hit it and bounce on it will still have lots of power when they reach - slightly delayed - you ears.. a perfect recipe for comb filtering.

Down from the desks, with the tweeters at ear height, there should be enough space to fit a computer keyboard. You don't need to move the monitors: in your case, you can simply keep the monitors where they are in the 3d space and slide the desk a bit forward. Yes you'll waste some space in the back (perfect location to host your cabling tough) but you could further improve your mixing sphere. Worth a try.
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Re: Box room problem or benefit?

Postby Gmonics22 » Wed Feb 12, 2020 8:00 pm

I'm not sure I understand what you mean about moving the desk? If I move it forward or back, I'll be sitting in areas where the room's response is much more uneven. I spent several evenings trying with different placements for the desk and the speakers (all over the place, and then literally shuffling a few inches at a time until it sounded ok) and going a foot closer to the front wall makes the resonance even worse, moving back puts me in the null in the middle of the room.

Also, regardless of positioning, any closer to the speakers and that resonance ramps up hugely. I'm really open to suggestions so thanks for tour thoughts, if I've misunderstood happy to be corrected!

Thanks :)
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Re: Box room problem or benefit?

Postby Martin Walker » Wed Feb 12, 2020 11:27 pm

Gmonics22 wrote:Ceiling light is bang in the middle, which precludes extending the cloud further back.

I had the same problem in my small studio, so I simply attached a longer mains flex from light pendant to a point further forward on the ceiling, and then installed a new light fitting there.

The ceiling cloud hides both the light pendant and the cable extension, so all you see is the new light fitting placed further forward :thumbup:


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