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Acoustics -How to treat a small tracking room Condenser Microphones
Old 11th December 2017
  #31
Gear Guru
Good

Yup, the .mdat is reading fine. Note the corner locations emphasise LF. Also we do not hear LF at low levels well. So the lowest modes may look more significant than they sound. Drums at the end walls will sound big and fat in this room. But do try turning them at different angles. The Kick in particular reacts to direction.
If the sound is too boomy, move away from the walls. At half length there will be a null of that mode and so on.

DD
Old 11th December 2017
  #32
What to do next ?

Thanks DanDan for looking at the measurement. It´s encouraging to know that I´ve got REW working correctly.
Now the big question: What next? There is still a flutter echo in the room which I have to tackle and also judging by the waterfall 48 hz is lingering on for longer than the rest of the frequency spectrum. I´ve still got quite a bit of wall area untreated, the lower part of the north wall is completely untreated, as is the south wall on both sides of the door and the area below the window.

Do you guys think it´s worth the effort to build a resonant panel absorber under the window, I´ve got room for a 1.75x .60 m to tackle or tame the 48 hz. According to F. Alton Everest´s Master Handbook of acoustics the absorber needs to be 10 " deep using 1/2" plywood.

I´m also wondering if building broadband absorbers for the north and south walls will be worth the effort. I´d appreciate any advice or opinions. Attached are some pictures of the untreated wall areas.

oddur
Attached Thumbnails
Acoustics -How to treat a small tracking room-e-wall.jpg   Acoustics -How to treat a small tracking room-n-wall.jpg   Acoustics -How to treat a small tracking room-s-wall.jpg  
Old 12th December 2017
  #33
Lives for gear
 

Quote:
Originally Posted by oddur View Post
Thanks DanDan for looking at the measurement. It´s encouraging to know that I´ve got REW working correctly.
Now the big question: What next? There is still a flutter echo in the room which I have to tackle and also judging by the waterfall 48 hz is lingering on for longer than the rest of the frequency spectrum. I´ve still got quite a bit of wall area untreated, the lower part of the north wall is completely untreated, as is the south wall on both sides of the door and the area below the window.

Do you guys think it´s worth the effort to build a resonant panel absorber under the window, I´ve got room for a 1.75x .60 m to tackle or tame the 48 hz. According to F. Alton Everest´s Master Handbook of acoustics the absorber needs to be 10 " deep using 1/2" plywood.

I´m also wondering if building broadband absorbers for the north and south walls will be worth the effort. I´d appreciate any advice or opinions. Attached are some pictures of the untreated wall areas.

oddur
I would build the panel absorber, as I found when I did my booth, that each absorber that I placed in the room shortened the modal ringing by about 60-80ms. Given the limited size, I would opt for hardboard (High density fibreboard), as 1/2" ply would be too stiff. Make sure you get an accurate measurement of the mass of the membrane to correct the calculation and therefore trap depth. The 5mm hardboard I bought for my traps varied between 4.9kg/m2 and 6.2kg/m2. The multi-layer absorber calculator was a real time saver: Multi-layer Absorber Calculator

As for broadband traps on the bare walls, yes, absolutely if you're still getting flutter, you want to tackle that with some broadband traps. Like I said in my last post, you're not going to get any appreciable or nice room sound out of a room this size, so make it as dead as possible.
Old 12th December 2017
  #34
Multi layer calculator

Many thanks Dpower, the calculator in your link is a real eye opener for me, it really popped my eyes right out of my head to be honest.

Back to the drawing board, I guess.

Thanks again
Old 8th January 2018
  #35
Continuing the build - Still scratching my bald head ;o)

I´ve built traps for the n & s walls. After playing around with the porous absorber calculator Dpower pointed out to me I realised that I had misunderstood the relationship between density of absorber material and low frequency absorption. For the n wall I made 3 60 cm X 200 cm traps 215 mm deep I used 30 kg/m2 density rock wool. For the s wall I made 2 60 cm x 200 cm traps 95 mm deep with the same density. I left a 45 mm space between the traps and the wall.

I also decided to postpone building the resonant panel absorbers under the windows based on DanDan´s suggestion "that the lowest modes may look more significant than they sound". I´m going to do a demo drum and acoustic guitar recording in the room to listen to the results. There´s still some ringing (flutter echo) in the room which I intend to tackle by placing 50 mm thick rock wool patches where needed. My next steps will be based on the outcome! Attached are a few pictures.
Attached Thumbnails
Acoustics -How to treat a small tracking room-frame.jpg   Acoustics -How to treat a small tracking room-n-wall-side-view-2.jpg   Acoustics -How to treat a small tracking room-n-wall-side-view-2.jpg   Acoustics -How to treat a small tracking room-n-wall.jpg   Acoustics -How to treat a small tracking room-s-wall.jpg  

Acoustics -How to treat a small tracking room-s-wall-traps.jpg   Acoustics -How to treat a small tracking room-n-wall-traps.jpg  

Last edited by oddur; 9th January 2018 at 04:06 AM..
Old 9th January 2018
  #36
Lives for gear
 

You're probably still getting flutter between floor and ceiling. I saw in an earlier post the two absorbers you put up, but I would recommend covering as much of the ceiling as possible (Especially if you want to record drums in there).
Old 10th January 2018
  #37
Ceiling absorber - Thanks for

Thanks DPower, you´re right. I have experimented with placing patches of mineral wool in a few places, including the ceiling. The ringing had disappeared. I´m surprised that the room does not feel overly damped, there´s still some liveness left , but I´m planning to randomly put wood laths over the traps for comfort and a finishing touch.
I´m going to ask my drummer friend to come over next week and set up the drum set and do some playing. I´ll post the results.

I want to thank everyone who participated in the discussion for their help.
Old 10th January 2018
  #38
Flutter echo eliminator



I mounted the last overhead trap, no more flutter echo and there is a slight crisp ambiance in the air. Hopefully I´ll be able to do some recording over the weekend.
Attached Thumbnails
Acoustics -How to treat a small tracking room-flutter-echo-eliminator.jpg  
Old 10th January 2018
  #39
Gear Guru
Crispy

Quote:
there is a slight crisp ambiance in the air.
I have seen similar comments regarding my vocal room and other fully dead spaces. 'airy'
Removal of early reflections leads a great clarity. Like outdoors.

DD
Old 11th March 2018
  #40
First demo recording

Hi guys

It´s been a while. I finally got a round to recording a demo. It´s acoustic guitars I recorded with a small diaphragm condenser w cardioid polar pattern positioned roughly 60 cm in front of the guitar body. I put gentle 2:1 compression on the way in. I hope you´ll excuse the poor playing! I´m quite happy with the sound in the room though.

I converted the file to mp3 to save space.
Attached Files

Sound demo.mp3 (4.39 MB, 3412 views)


Last edited by oddur; 11th March 2018 at 11:04 PM..
Old 12th March 2018
  #41
Lives for gear
 
robert82's Avatar
That's a good clean sound! No boxiness. I'm still working on my room . . . but I've put some slats over some of the rockwool . . . Now I'm wondering if I should have left it more dead. By the way, I put your track into Reaper and added some reverb - your setup takes it very well, creating a nice space. The "dead" room becomes a blank canvas to add your own sonic spaces. Oh, and your guitar playing is just fine!
Old 12th March 2018
  #42
Room sound

Thanks Robert82. I´ve also been thinking of putting up some slats over the traps in my room, but wanted to experiment a bit before deciding. I intend to do some more experimenting with acoustic guitar using an omni capsule to see if that will reveal some unpleasantness in the room sound. After that I intend to record a full drum set once I´ve built up enough courage to do so ;o)
Old 12th March 2018
  #43
Another demo -

Hi again

I just finished another demo. Small diaphragm cardioid for the guitar, this time I moved it a little farther from the guitar, roughly 70 cm. I also added some percussion elements recorded using a spaced pair of ribbon mics spaced 65 cm about 30 cm from the ceiling. I also added a little reverb. I´m optimistic that this space can be used for recording. I´d appreciate comments (positive or negative) ;o). For the drum recording, my drummer friend won´t be able to come over until the end of the month.
Attached Files

Nylon mix.mp3 (3.46 MB, 3309 views)

Old 26th March 2018
  #44
Omni mic recording - test

Hi, I´ve been doing a little more experimenting this time using an omni microphone, same position and distance as before.

The first clip is dry, but the other one is sweetened a little bit with slight compression and impulse response of a Bricasti M5 large wooden room for comparison.

My conclusion after listening a few times is that the room is as expected, not contributing much to the sound if anything at all.
Attached Files

Omni dry 65 cm.mp3 (1.90 MB, 2992 views)

Omni ir wooden room 65 cm.mp3 (1.90 MB, 3046 views)


Last edited by oddur; 27th March 2018 at 10:06 AM..
Old 27th March 2018
  #45
Gear Guru
Outdoor

Both sound good to me. That sounds like a small guitar. They are quite 'tonal' to my ear. I would recommend vocals rather than instruments when testing for neutrality. Or compare clips of the instrument recorded outdoors with in the room.

DD
Old 27th March 2018
  #46
Recommendation

Good point DanDan. I´ll have to wait till spring for the wind to settle a bit though before recording the guitar in the outdoors;o). You are right it is a small guitar, it´s a baby Taylor. I was quite surprised how well it sounds recorded.

I was planning to experiment with wooden laths in front of the traps but I´m going to wait a while and do some serious recording to see how it works out before deciding if it´s worth the extra effort.

oddur

p.s. thanks for your inputs
Old 5th April 2018
  #47
New sound file

I made a mistake on the last recording I sent, it was recorded using a hypercardoid capsule not an omni. This one however was recorded using an omni. Sorry for the confusion.
Attached Files

micro blues.mp3 (1.56 MB, 2790 views)

Old 19th April 2018
  #48
Drum recording

Hi guys

We´re working on a song and made a demo recording. Attached is a sample of the drum sound in the small room. No processing. I´m optimistic that I can use tracks recorded in the room without major problems.
Attached Files

trommu mix.mp3 (1.65 MB, 2476 views)

Old 22nd April 2018
  #49
Drum sample in context - Comments appreciated ;o)

Hi

Attached is the drum recording above in context, rough mix. Everything recorded di´d except the drums.
Attached Files

Sample.mp3 (548.5 KB, 2400 views)

Old 25th April 2018
  #50
Conclusion

Hi all

This has been quite a ride for me, trying to apply the acoustics theories I´m having problems understanding to my modest room.

I´ve been doing recording of music as a hobby for the past fifteen years, ranging from a piano and violin, accordion group, choir and my band wherein I play guitar. All the recordings have been made in far less than optimum locations. After the fact I have struggled to produce presentable mixes with questionable outcome in many cases .

I am very pleased to report that the recordings I make in my new modest space (studio ;o)) are so much easier to mix and sound far superior to any of my previous recordings.

Most of the success is due to this wonderful forum. Now I´m going to sign out and start making music with my fellow band members.

Thanks guys for your participation and interest and listening to my demo recordings.

Cheers
Oddur
Old 16th May 2018
  #51
Drum track -

Hi gang

just finished a new drum session, different drummer, a little more heavy handed than in the other recording. Same setup except I also added a room mic in front of the bass drum pointed away from the drum into the doorway of the adjacent room which is slightly larger than the drum room with far less trapping. It gives a sense of added depth and liveliness in my opinion. What do you guys think? Enjoy.
Attached Files

Jón hrk tromm.mp3 (1.91 MB, 1837 views)

Old 18th May 2018
  #52
Lives for gear
I haven’t visited this thread for a while, since you were getting more knowledgeable advice than I can provide. After listening to your latest drum track, I have good and bad news.
Bad news first. I really don’t like the sound of the drum tracks.
Good news: VERY good news! The room sounds very good! I can hear what I don’t like about the drums without feeling that I’m listening mainly to the “boom in the room”. The room sounds very neutral. It sounds like you have clarity and a nice even ambiance with no obvious frequency-centered resonances.
The things I don’t like about the drums don’t really matter in this thread. Most of it is just personal taste and the imaginary track the drums might play with. What matters is how well I hear those things. I feel I could bring a kit and the mics I like to your room and get a recording I’d really like. And that means, in my opinion, you have achieved your goal. Congratulations!
Old 18th May 2018
  #53
Thanks

Many thanks Bushman for your kind and candid critique and insight, it´s refreshing to get feedback. I appreciate your opinion, both the good and the bad .
Up until now I´ve been focusing on the room, now I can start working on the sound of the drums and other instruments I record in the room, I´m sure there´s a steep learning cure I have to tackle.

Take care
Oddur

Last edited by oddur; 18th May 2018 at 11:15 PM..
Old 20th May 2018
  #54
Gear Guru
Phat

The Lo Fi Indie thing brought a 'new' drum sound with it. So good or bad drum sounds....... Speaking as a Recording Eng. Acoustician, and Drummer, here is great tool Tune Bot Drum Tuner

DD
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