Garden mix room near Nottingham, UK

#151

That’s a good idea, Starlight - I had them in my last house.
However I’ve been worried about any vibration from these doors so I’m not sure if the magnets on those things would be strong enough to hold the doors still or against any foam seal type thing (if needed). My current thinking is a magnetic latch like you get in sideboard type cupboards - found some with a 5kg force (no idea if that’s enough!).

Hmm I’ll ponder over it and maybe try a set of push sprung closers first...

Gareth

#152

Greetings Gareth,

My current thinking is a magnetic latch like you get in sideboard type cupboards - found some with a 5kg force (no idea if that’s enough!).

You could fashion your own strong magnetic catches with a small rare earth magnet and a small piece of steel.

All the best,

Paul

#153

Days 166-168

On Friday with help from my brother in law and my Dad we glued down the EPDM roof and fitted the edge trim. This was one of those jobs that just needed doing and we kept getting rained off. It looks a lot better from bedroom windows now!

On Saturday I finished the cupboard and created a prototype desk out of the softwood 18mm ply. It looks OK on the photos but I really did cut all the parts quickly. If it works then I'll re-make it in baltic birch ply at some point.

Then today I got all the offcuts of wood out and tools, and took another REW measurement with the finished soffit wall. It's not made a huge difference which is a bit disappointing as it has all those hangers, although it has smoothed the 62Hz peak. I suppose the rest of the room is untreated so there's a lot of hard surfaces for sound to bounce off.

I also popped the desk in there and did a measurement as a comparison. As you can see the desk reinforces a null at 128Hz - not sure if there's much that can be done about that? Hopefully the other treatment will help.

Next plan is to add RWA45 to the ceiling bays and then take another measurement. After that rear wall hangers.

#154

Greetings Gareth,

Love the exterior photo of the studio building. Stunning.

We'll all be over this evening...

All the best,

Paul

#155

Thanks Paul - you’re very welcome. We have a fire pit and cold beers....

That roof will eventually have a growing roof on it (sedum roof).

Cheers
Gareth

#156

Greetings Gareth,

That roof will eventually have a growing roof on it (sedum roof).

Yes, I saw your post about the green roof.

All the best,

Paul

#157

Knocking down the 62Hz peak is no mean feat by the way, nice one. Could you remind us of the room dimensions please? I am guessing that is the secondary length mode.

Also some good stuff between 80-120Hz.

I also guess the null about 75Hz is from the height mode? Your ceiling treatment should hopefully help there.

From memory, the null around 120Hz is usually from the floor bounce, which is presumably why the desk has altered it.

It would be interesting to see before & after spectrograms or waterfalls if you have them. Or even just attach the mdats

Cheers!
Jennifer

#158

Hi Jennifer
The MDAT should be attached above, and of course you’re right about checking the waterfall plot.

The room is 3.25m wide, 5.5m long and 2.25m tall.

So yes the 62hz is a length mode, and yes the 75hz is half the first ceiling to floor mode.. good guesses!

Started putting 10cm thick rockwool into the ceiling today so once that’s done I’ll take another set.

Cheers
Gareth

#159

Your soffits have done an excellent job, look at the reduction in decay time in the spectrograms;

Baseline

Soffit

Another way of looking at this in the RT60 plot;

You are correct about the large number of remaining reflective surfaces affecting the sound. Have a look at the impulse plot, there are some early reflections still close to -10 dB in the first 30ms or so. The brain will interpret these as a smearing, distortion, degradation (or what have you) of the sound rather than distinct echos. A good target to aim for is less than -20 dB.Jennifer

Cheers!

#160

Day 170

Thankyou very much for that, Endorka, much appreciated. As you'll see from below I'm in need of your REW skills again, though!!

After work today I managed to glue the remainder of the ceiling cavity insulation into place, clear the room and take the next set of REW measurements. With the exception of the space near the door, needed for head height as people walk in, the ceiling has 100mm of rock wool RWA45 glued with spray glue to the cavities (sprayed to both the rock wool and the ceiling). I used one piece of wood batten to go across each to take the weight and hopefully stop the rock wool sagging over time. I think I got through 5 or 6 cans of spray glue just doing the ceiling!

I also added the same rock wool to the first reflection points either side of the soffit walls, and will wait before putting any more in the side walls to get the rear treatment in and see what my measurements are like.

I emptied the room onto the garden again (no rain thankfully), and took the next set of measurements. However, something weird had happened with REW or something else that meant my first set of readings looked odd. I checked the sound levels using my SPL meter and bizarrely had to turn up the output of my interface to get back to 80dB. I re-calibrated REW but somehow now the readings are showing as louder. I had taken screenshots of my mic gain and speaker output settings on my Universal Audio software, but for some bizarre reason something had changed to make the sound from REW/computer quieter, despite the level not changing on the output volume. Maybe the level of the signal from REW had reduced? I'm very confused by this. I saved a version of the MDAT file where I'd taken a reading of the left speaker with the volume level set as it was before I re-calbrated. However this shows no bass at all below 50Hz. The readings taken post increasing/re-setting the level to read 80dB on my SPL meter show around 10dB louder on REW and there are some really odd anomalies in the response curve. I suppose it's possible I'd knocked the measurement mic so I need to re-check that, but even so this looks weird and I can't understand what made the sound level drop.

Here's what I mean about the readings. Some good news but some weirdness too:

Even more disturbingly, everything sounded harsh when I played music. I expected a bit of the opposite to be honest. I'm now really worried that the settings the rep from Neumann suggested for the EQ on the monitors have caused this, as they recommended "Regarding the loading compensation caused by the inwall mounting I would start with Bass – 5 dB, Low mid -3 dB." This is what I did. I'm wondering if what this has done has simply made the treble louder. Other than that the sound is good and soundstaging is great. The only way to change this is take apart the soffit walls, unfortunately, which I'll do if that's the problem, but I want to be sure it is first.

I'm wondering if what I'm hearing could be related to reflections off my cupboard doors? The AMRAY trace below suggests I could currently be getting sound bouncing off the back then off the cupboard doors, but I defo hear a harsh sound. I tried adding an EQ to music playing, turning down 10KHz and above and that helped. All together a disappointing evening. I need help!!

If anyone can help make some sense of this, the two MDAT files are saved below. V2 is with the volume increased back to 80dB per speaker.

#161

I'll have a look Gareth. I would certainly not expect such large changes from the treatment you have added since the 16th. Did you change the speaker EQ settings after your tests of the 16th?

#162

I've aligned the "soffits" and "ceiling and soffits" measure from the V1 set, left speaker only, to the same volume in the midrange using the REW alignment tool

You've no bass to speak of. It looks like a high pass filter has been engaged somewhere. This will reduce overall volume, so turning it up to equivalent SPL as before will increase the mids and leave you still with not enough bass. This would explain the harsh sound.

I'd suggest checking your entire signal chain, hardware and software including plugins, monitoring EQ, etc.

#163

Thankyou Endorka. I thought I was going mad.

I have absolutely no idea what could have caused that. The eq switches on the back of the monitors are impossible to get to without dismantling the soffit wall so they haven’t been touched.
As both speakers are doing the same thing it suggests something odd at the audio interface end. This would also explain how music sounded harsh. Not a clue what could have created this issue but will reset my interface tomorrow and see if I can figure it out.
Thanks once again
Gareth

#164

I am sorry that I am of no help here. If that was my situation I would get my usual headphones out and check that the sound is normal through them. Basically, as Jennifer mentioned, going step by step through the signal chain to make sure it is set right and sounds right at each step.

#165

Thanks to Endorka helping me engage my brain last night, today I took an hour out at lunch to go back into the studio to see if I could figure out what went wrong. Endorka suggested that it looked like a high pass filter was engaged, but there isn't the possibility of that in the UAD console!

I played some music and it didn't sound as harsh, and tried a few things just checking both speakers were playing equally (ie putting music in mono, panning from one to the other etc). Just to be safe I did a hardware reset on the UAD Arrow interface I've been using for these tests, and then checked I was still getting 80dB at the measurement mic from one speaker.

I double checked mic positioning and it did seem to have been knocked slightly, so I reset the position with my laser measure.

After that I did a quick test with everything and me in the room, and the graph seemed much more sensible. So I emptied the room onto the garden (of course it started raining as soon as all the tools were outside, and stopped as soon as I brought them back in), and repeated last nights tests. Once I'd done them, I knocked the mic off position and did a test, just to see if that might have been the culprit.

Todays readings seem much more plausible, are showing as quieter (although still about 4dB louder than the previous tests). I cannot explain what went on last night but things do seem more normal today. The test with the mic knocked out of place was very similar to these others, so that was not the reason.

MDAT file below, but we can see in the graphs that the ceiling treatment has smoothed out things quite a bit, but has accentuated some dips present around 400-500Hz. Not sure what they are but once the rear wall is done I'll use a tone generator to hone in on that area.

SPL:

Waterfall plot with just soffit:

Waterfall plot with soffit and ceiling:

Spectrogram with just soffit:

Spectrogram with soffit and ceiling:

You can also see on the reverb time graph below that the RT has reduced considerably. There is a peak in the reverb around 100Hz, though, which hopefully will die down with the hangers on the back... but could also be floor bounce so I'll drop an absorber there and test that at some point.

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