Garden mix room near Nottingham, UK

[endorka]

That is excellent. RT60 getting close to the recommendation of EBU Tech.3276 throughout much of the frequency range.

Is music audibly clearer in there now?

Cheers,
Jennifer

[garethmetcalf]

Music does sound clear and moving around the room it’s quite even. I’m looking forward to seeing what impact the hangers will have on the low frequencies as unsurprisingly they change as you walk up and down the room.

The top end is still a bit much, not as bad as yesterday, so even with the RT being as low as it is I wouldn’t be afraid to add more treatment. I have a bit of area above the cupboard where the ceiling is hard - the underside of the silencer - and I’m worried about reflections, so I’m going to try hanging a pre-made 2’ x 4’ absorber there from a previous studio build. I may replace this with a cloud at some point but for now this seems worth trying. I can also put mood lighting behind it too.

This feels like I’m getting towards the end of a long and tiring phase 1, to a place where I’ll be able to use the room and then refine it.

[garethmetcalf]

Day 176
I spent bits of time last Thursday eve, Friday morning and this evening working on the hangers. Of all the jobs I’ve done this has been one of the worst... continually getting covered in fibreglass. Mounting them by cable ties to the wooden battons has meant getting in amongst the hangers and rockwool that’s filling the stud bays. Horrid.

I mounted the 2x4 absorber I had spare with some led lights behind it as a sort of cloud as well. The lights look cool.

I’m nearly there with it but ran out of spray glue and ducting for my air intake so I’ll have to put the last two in tomorrow eve. At that point I’m emptying the room and doing another REW test and also getting it clean enough to use as a studio with a client/friend on Friday!

The room sounds too dead now, I think, but the tests will confirm.

[Starlight]

Source of the post... working on the hangers. Of all the jobs I’ve done this has been one of the worst... continually getting covered in fibreglass.

I understand; I felt the same doing my insulation-filled drop ceiling, pushing insulation up into a space above my head.

Source of the post... getting it clean enough to use as a studio with a client/friend on Friday!

That is not simply a step forward; that is a milestone!

[garethmetcalf]

Day 177 (one day off half a year!)

Last night I worked until 11.30pm trying to get to a stage where I could stop being covered in fibreglass and sawdust. I put the last two hangers in, cut holes in sides of the rack mount parts of my desk (as per Stuart's desk design), attached large wheels to the desk and sanded the floor ready to apply some varnish.

Finished hanger wall. The biggest hanger is about 64cm deep and 2m tall.

Prototype desk construction

Front of room

I also did some more REW tests and the results are below. The MDAT is attached.

SPL: baseline test (empty room) vs now - left speaker

SPL: baseline test (empty room) vs now - right speaker

RT60: comparison between baseline, soffit wall, ceiling treatment and then now (rear wall). Note the 100Hz ish thing that's disappeared. I wonder if that's due to the cloud type absorber I hung?

Waterfall for soffit and ceiling treatment:

Waterfall for rear wall (now) treatment - quite a bit smoother, but still some really low rings to look at - I wonder if that could be related to having the fan on?:

Spectrogram for soffit and ceiling treatment:

Spectrogram for rear wall (now) treatment:

I also repeated my sound reduction test with the correct settings on the level meter. It was still loud outside at 9.30pm with birdsong etc (around 58dBC background noise next to the house). 98dBC at the desk 68dBC stood next to the door, dropping to 60dBC when the bass in the track stopped. Because the birdsong etc was so loud I'm still not convinced this is a true reflection so I'm going to have to repeat it at 1am or something!

BUT HOW DOES IT SOUND? It sounds pretty good. The bass is quite even as you move up and down the room, which is a great relief. It does sound dead when talking, as demonstrated by the RT60 graph, so I need to see what that feels like to work in before deciding what to do.

It does still sound quite bright and I'm hoping that at some point soon Stuart will return and be able to apply some digital tuning to the room which can include a HF roll off. Again, I'm going to use the room a bit and get used to it before doing anything else.

The only issue I noted was related to the treble. Stood in front of the desk, around 1/3 of the length of the room, if I moved my head up and down I heard a phasing going on with the treble. I rolled the desk out the way and it wasn't as pronounced, so I don't know if that was something strange to do with the desk. Again, once there is a screen, keyboard, mouse etc on the desk perhaps there'll be some natural diffusion. The only other thought I had was whether this is some kind of edge diffraction from where the speaker stops and the front of the baffle starts. I might try putting some backer rod in that really small gap to see if it makes any difference.

Has anyone experienced anything like this?

[endorka]

I'll have a look at the mdat later Gareth.

In the meantime, I noticed the brightness thing getting worse and worse too as I added more and more absorption. I noticed something predictable because I was making consistently well balanced but dull mixes, and always in the same dullness. So after checking them elsewhere I derived a high shelf boost that made them proper. I thought I was going nuts until a search on the internet showed DanDan on gearslutz had experienced the exact same. The solution was a B&K curve in the monitor signal chain, essentially the opposite of what I had derived during mastering to bring proper tonality to my mixes

Not everyone experiences this though!

Cheers,
Jennifer

[garethmetcalf]

Thanks Jennifer, makes sense. In my last studio Stuart did digital tuning for me and applied a house curve but I don't know what that was. Perhaps it was B&K.

I'll look into adding that into my chain, although annoyingly with my UAD interface there isn't an obvious way of applying EQ to the output, and I'd rather not do it in Logic in case I accidentally leave it on when bouncing!

Looking forwards to your comments on my MDAT anyway.

Cheers
Gareth

[endorka]

Source of the postI'll look into adding that into my chain, although annoyingly with my UAD interface there isn't an obvious way of applying EQ to the output, and I'd rather not do it in Logic in case I accidentally leave it on when bouncing!

No idea if there is an equivalent in Logic, but in Reaper there is a specific place for monitor FX. They only go to the monitor output, and are not included when bouncing.

[endorka]

No doubt Gareth will arrive at some enlightenment with respect to the phasing / comb filtering effect based on the inspiration from Ron's thread. Here are some REW thoughts in the meantime.
The addition of the acoustic hangers at the rear wall has had a huge and consistent effect on the number of reflections bouncing around the room, you can see this by the speedier decay of the impulse chart. I think there is some very good information about exactly what qualities one should expect look in this in either Everest or Gervais' book - can't remember which at the moment, sorry! It would be worth checking these. From memory, the linear decay you have is very much sought after.

The phase response is interesting. I am winging it here - I almost had my mind wrapped round these concepts last year, but it has slipped a bit. I believe the bad stuff is happening when you get these large steps or discontinuities in the curves. I think these represent the phase shift due to a reflection - or perhaps something else - and whereabouts in the frequency spectrum it is having an effect. There are far fewer of these since the addition of the acoustic hangers in the rear wall. Nice.

Based on your own RT60 charts the room is getting a little dead around the 250Hz - 2kHz range, if you are going after around 200ms response. I have seen Stuart write about ways to re-introduce some liveness around those areas without affecting others, so worth having a look about for that. If you haven't done so already, have a look at EBU Tech.3276, it gives a good range of acceptable times for the various frequency ranges. It mentions that longer decay in the lower pitches is acceptable up to a point, so no need to bring that all the way down to 200ms.

Cheers!
Jennifer

[Starlight]

Source of the postNo idea if there is an equivalent in Logic, but in Reaper there is a specific place for monitor FX. They only go to the monitor output, and are not included when bouncing.

I am a Logic user and don't believe Logic has this, possibly because Logic is very much studio software. Programs that aim at being useable in a live situation, such as Reaper and Ableton Live, are more likely to have this feature.

[endorka]

Source of the post

Source of the postNo idea if there is an equivalent in Logic, but in Reaper there is a specific place for monitor FX. They only go to the monitor output, and are not included when bouncing.

I am a Logic user and don't believe Logic has this, possibly because Logic is very much studio software. Programs that aim at being useable in a live situation, such as Reaper and Ableton Live, are more likely to have this feature.

Interesting, I had no idea about that, thank you.

I reckon the best solution is to have it done in hardware. Minidsp do boxes for this, and I think Stuart has recommended a Behringer FBQ unit for his final digital tuning.

Cheers,
Jennifer

[endorka]

Follow up to viewtopic.php?p=3874#p3874:

The relevant information starts at Everest chapter 24 "Acoustics of Control Rooms", from page 257 onwards.

Your ETC graph is indeed excellent, and the "linear" decay is sought after, but of course since the scale is in decibels, it actually represents an exponential decay of the diffuse sound field.

Further on in the chapter he recommends diffusers at the rear wall for some control rooms to re-introduce diffuse rather than specular reflections. Might help increase your midrange RT60? From memory though, there must be at least 10 feet distance between the mixing position and the diffuser for this to work properly.

[garethmetcalf]

Fantastic work, thanks Jennifer. It is dead in there and I had through to try and find posts on John Sayers forum about what I can add to the back wall to let bass through but reflect some mid/high. My memory tells me plastic sheeting was used...

Diffusion could be a good shout - I’ll measure the distance to see how near to 10’ it is. I have a sofa on order which will of course soak up yet more reverberation so I’m going to need to do something. I think I’ll do it on the rear wall rather than the ceiling as I don’t want any reflections from above.

I had a short session with a long time client on Friday and the room performed admirably. He was very impressed with the consistency of the bass response as you moved around the room and he didn’t think the room sounded too bright, but I do think it a little harsh.

I already have one of the Behringer FBQ boxes so will try and get a HF roll off on it when I reclaim it from my parent’s house.

With some stuff on the desk the phase shift/comb filtering wasn’t obvious, thankfully but I will continue to check this as I add more furniture and stuff.

Very quick setup for Friday, having varnished the floor in the week:

I’m going to try and get the material on the ceiling this week and make some frames for material for the walls, so that if I decide to change the wall treatment I can just take the frames off the walls. I think if I use a few nails with no heads to hold the frames to the wall the nails should go through the fabric and be hidden...

[endorka]

Fantastic to hear the session went well!

Source of the postIt is dead in there and I had through to try and find posts on John Sayers forum about what I can add to the back wall to let bass through but reflect some mid/high. My memory tells me plastic sheeting was used...

I remember that too, and it gave me the heeby jeebies. Makes me think of a another grim way of exiting this world from the Omen movies. That's the second time - you did it with the glass sheet in the car too

In all seriousness, I've no idea how well plastic wrapped insulation would conform with UK building code.

Another way of introducing reflections is with wooden slats. I remember Stuart testing their effect by stretching plastic where you think the wood should go, to test the effect before committing to a certain pattern.

I’m going to try and get the material on the ceiling this week and make some frames for material for the walls, so that if I decide to change the wall treatment I can just take the frames off the walls. I think if I use a few nails with no heads to hold the frames to the wall the nails should go through the fabric and be hidden...

These are quite useful for this purpose too. From Screwfix https://www.screwfix.com/p/flush-mounts ... pack/11423

[Starlight]

Source of the postAnother way of introducing reflections is with wooden slats.

If you look at jhbrandt.net and click on resources at the top, then look for the section entitled Drawings! John publishes his plans for slatted traps which may be worth looking at. John uses a repeating single size slat and gap. While you are in that section, look also at the Prime 523 diffusor as that will be what you want on your back wall, so long as it is 3.5 metres behind the listening position. I will soon be making one of those.

Other slat options include a 3-4-5 sequence which I think Philip Newell used a lot (maybe still does but I think his son Joules has taken over the reins of running the business) and the late Boggy Petrovič created a random sequence that was hailed by the pros. There are others that I cannot remember but these two at least can be found on gearspace.com. If you need me to search, just ask.