Quantcast
Room Measurement Results - good? - Gearspace.com
The No.1 Website for Pro Audio
Room Measurement Results - good?
Old 27th January 2013
  #1
Gear Nut
 
🎧 5 years
Room Measurement Results - good?

I've attached my acoustic measurement results:

Freq Response, ETC, Spectral Decay - for all frequencies and a detailed 10-500Hz sweep. Sweeps lasted 20 seconds. Used Fuzzmeasure.

Can anyone help me judge the results? What should I do with the room now?

Room is 16' by 11' 5". Speakers are facing the long end of the room as they should. Ceiling is 8 feet at the speaker end, 10" 7" at the "back". There's an untreated en-suite bathroom and walk-in closet. Also serves as my bedroom. Small bed in front of 4' high bookcase.

I've attached room pictures that are slightly warped because of the panoramic function but easier to get a sense of the room. No floor plan yet sorry.

AL
Attached Thumbnails
Room Measurement Results - good?-waterfallzoom.jpg   Room Measurement Results - good?-t30.jpg  
Attached Images
File Type: jpg FreqRETC.jpg (84.7 KB, 400 views) File Type: png ImpGraph.png (27.0 KB, 321 views) File Type: jpg Waterfall.jpg (92.3 KB, 383 views) File Type: png EDTReverb.png (43.7 KB, 359 views) File Type: png T20Reverbtime.png (44.9 KB, 310 views)
Old 27th January 2013
  #2
Gear Nut
 
🎧 5 years
Attachements for 10Hz - 500Hz sweep here.
Attached Thumbnails
Room Measurement Results - good?-to500hz.jpg   Room Measurement Results - good?-specdecay500hz.jpg  
Old 27th January 2013
  #3
Gear Nut
 
🎧 15 years
I've been working on my room (still in progress) and I use FuzzMeasure too. To evaluate the lows, what I was told around here is to set the smoothing on the waterfall to off, duration to 500ms, minimum frequency to 10 Hz, maximum to 300 Hz, and min magnitude to -40 db.

With my very small knowledge, what I can tell is to deal with the dip between 70 - 100 Hz.

I've also been told that EDT, T20 are not useful when evaluating a small room like yours (which is about the same size as mine). ETC is important, however.

Some of the hardcore guys around here will just rather hear the actual IR file exported and posted as a .wav or /aiff file at 24 bit with a healthy level.

Hope this helps a little.

Keith
Old 27th January 2013 | Show parent
  #4
Gear Guru
 
Glenn Kuras's Avatar
 
🎧 15 years
Quote:
Originally Posted by kwow ➑️
Some of the hardcore guys around here will just rather hear the actual IR file exported and posted as a .wav or /aiff file at 24 bit with a healthy level.

Hope this helps a little.

Keith
Plus one.
How is the room treated now?
Old 28th January 2013
  #5
Gear Nut
 
🎧 5 years
Sorry for the delay, did not get notifications. I changed emails but my forward from the old wasn't setup right.

Thanks a million Keith, will do and report back today.

Quote:
Originally Posted by Glenn Kuras ➑️
How is the room treated now?
The bass traps you see in the pictures are DIY wood frames, filled with Knauf fiberglass insulation. Covered in black landscape fabric and/or burlap. I made three sizes:

1) deep: 2' by 2' by 4' high
2) half depth: 13" by 2' by 4' high
3) half depth and tall 13" by 2' by 8' high

The three ceiling modules directly above the workstation are filled with mineral wool / rockwool by "mistake". All the modules at the "first reflection" points are half depth, apart for the modules to the left and right,.

Thanks for your previous advice on DIY traps, Glenn.

Installed inexpensive diffusers a bit everywhere at the back and sides.

Ceiling towards the back half of room is untreated. ( see pictures )

Would the furniture resonate whether it had nothing in it or not ? ( see pictures ) The strange "cabinet" with laundry hamper on top is my dismantled desk modules.
Attached Thumbnails
Room Measurement Results - good?-dscf1247.jpg   Room Measurement Results - good?-dscf1248.jpg   Room Measurement Results - good?-dscf1250.jpg   Room Measurement Results - good?-dscf1249.jpg  
Old 28th January 2013
  #6
Lives for gear
 
jim1961's Avatar
 
🎧 5 years
On your ETC, show one only with the first 60ms or so. Its the early returns that are most important to see clearly.

Your noise floor seems only -30db. Should be in the -50 to -60 range at least. Try making the tests with a louder volume and/or higher mic levels.

Show your waterfall out further, to 600ms - 1000ms.
Old 29th January 2013
  #7
Gear Nut
 
🎧 5 years
Acoustic Test Results take 2

Here are the results, as requested.
Attached Images
File Type: jpg 10-300HzTest1-FreqResp.jpg (89.9 KB, 366 views) File Type: jpg 10-300HzTest1-ETC60ms.jpg (99.5 KB, 302 views) File Type: jpg 10-300HzTest1-WFall1000ms.jpg (80.6 KB, 319 views) File Type: jpg 10-300HzTest1-WFall600ms.jpg (90.4 KB, 359 views) File Type: jpg 10-300HzTest2-FreqResp.jpg (99.9 KB, 326 views) File Type: jpg 10-300HzTest2-ETC60ms.jpg (98.3 KB, 360 views) File Type: jpg 10-300HzTest2-WFall1000ms.jpg (81.6 KB, 318 views) File Type: jpg 10-300HzTest2-WFall600ms.jpg (89.8 KB, 323 views)
Attached Files
File Type: aiff ImpTest1.aiff (6.00 MB, 96 views)
Old 29th January 2013
  #8
Gear Nut
 
🎧 5 years
Am I going crazy or are not all my pictures showing up even though they are loaded? I initially had nine on my first post which included the room pictures.

Here they are again.
Attached Thumbnails
Room Measurement Results - good?-dscf1244.jpg   Room Measurement Results - good?-dscf1243.jpg   Room Measurement Results - good?-dscf1241.jpg  
Old 29th January 2013
  #9
Lives for gear
 
jim1961's Avatar
 
🎧 5 years
The ETC needs to be across the full bandwidth (all frequencies). In addition to the <300hz waterfalls, show the full frequency range ones also. Even if your focused on the bass range, its good to see how the mids and highs decay relative to the bass.

You doing a good job.
Old 29th January 2013 | Show parent
  #10
Gear Nut
 
🎧 5 years
Quote:
Originally Posted by jim1961 ➑️
The ETC needs to be across all frequencies.
See attached

Quote:
Originally Posted by jim1961 ➑️
In addition to the <300hz waterfalls, show the full frequency range ones also.
See attached but I had done so before. Results are similar.

Quote:
Originally Posted by jim1961 ➑️
You doing a good job.
Thanks. You can't believe how much I'm enjoying this and appreciating the help.
Attached Images
File Type: jpg AllFreq_ETC_FreqRes.jpg (93.9 KB, 342 views) File Type: jpg AllFreq_Waterfall.jpg (77.4 KB, 327 views)
Old 29th January 2013
  #11
Gear Guru
 
1 Review written
🎧 15 years
Odd

Try importing that Impulse Response. Very strange decay times of several seconds rising at HF. However the Waterfalls and FR look OK.
Best to do seperate tests for L R and L+R

Overall you response is not bad at all. You might be seeing a bit of resonance from a coupled space, at LF. The dip is the one to go after. BIR. Speaker position or listener position can help a lot, as can a sub, which can be freely placed.

Take a look at the before and after response on the last graph Here.
Movement only did this. Might be worth reading the primer as it covers all that single speaker, pointing the mic, and so on.
DD
Old 29th January 2013
  #12
Lives for gear
 
jim1961's Avatar
 
🎧 5 years
Your ETC looks very good.

The FR is good down to 320hz or so. That 65hz-120hz null could be addressed. That is a very important part of the bass range and shouldnt be 10db down.

I would definitely try some FR readings in different parts of the room in a grid of sorts around the listening position. Perhaps you can find a sweet spot to avoid better the bass nulls.
Old 29th January 2013
  #13
Gear Guru
 
1 Review written
🎧 15 years
Two

Indeed the ETC does show a pretty dead scenario, in general. But there does seem to be a very strong reflection (or the other speaker).
Similarly if two speakers are running the HF response is not to be trusted.
Room Measurement Results - good?-screen-shot-2013-01-29-20.12.59.jpg

Also this looks very odd.

Room Measurement Results - good?-screen-shot-2013-01-29-20.16.22.jpg

DD
Old 29th January 2013 | Show parent
  #14
Gear Nut
 
🎧 5 years
Full Spectrum Impulse Response attached.

Quote:
Originally Posted by DanDan ➑️
Similarly if two speakers are running the HF response is not to be trusted.
All tests running from one speaker, left.
Attached Files
File Type: aiff ImpRespJan29.aiff (6.00 MB, 118 views)
Old 29th January 2013 | Show parent
  #15
Gear Nut
 
🎧 5 years
Quote:
Originally Posted by DanDan ➑️
Indeed the ETC does show a pretty dead scenario, in general. But there does seem to be a very strong reflection (or the other speaker).
Similarly if two speakers are running the HF response is not to be trusted.

<graph>

Also this looks very odd.

<graph>

DD
jim1961 pointed out the impulse response should be full spectrum. So the ImpTest1.aiff file you took the time to analyze was from a partial run from 10-300Hz. My ignorance, sorry DD.

I have included a full spectrum aiff above. Sorry about that.
Old 29th January 2013
  #16
Gear Guru
 
1 Review written
🎧 15 years
Full

Good. No worries um and no need to be sorry!
I normally run a full sweep every time. This leaves all the viewing options open later.

The very very early reflection in your ETC is very strong. Is there a desk or other surface near the speaker to ear path?
Also as you can see with the 5 Second decay, something is flawed in the measurements or Exporting of them.

DD
Old 30th January 2013
  #17
Gear Nut
 
🎧 5 years
New Impulse Response aiff, no Keyboard or stand. I still see the strange 5 ms lead-in though. I posted a question on the Fuzzmeasure discussion board.
Attached Images
File Type: png ImpRespNoKbrd.png (63.5 KB, 292 views)
Attached Files
File Type: aiff ImpRespNoKbrd.aiff (6.00 MB, 56 views)
Old 30th January 2013
  #18
Gear Guru
 
1 Review written
🎧 15 years
Reflections

Try moving the speaker ahead of the screens.
It is a very very short reflection, perhaps the speaker box itself, but it seems very very strong.
Your new measurement has very smooth third octave T30's. The weird long HF thing seems to be gone.
I see a lot of subby rumble. Traffic?

DD
Old 30th January 2013
  #19
Gear Nut
 
🎧 5 years
Bass Trap?

It could be my bass trap frames. They have vertical 2" by 2"s supporting the corners. Actually 1 1/2" by 1 1/2 "
Old 30th January 2013 | Show parent
  #20
Lives for gear
 
jim1961's Avatar
 
🎧 5 years
Quote:
Originally Posted by DanDan ➑️
Try moving the speaker ahead of the screens.
It is a very very short reflection, perhaps the speaker box itself, but it seems very very strong.
Your new measurement has very smooth third octave T30's. The weird long HF thing seems to be gone.
I see a lot of subby rumble. Traffic?

DD
342us is a variance of only 4.6" from the direct path. That could easily be cabinet diffraction, the mic stand, or the listening chair.
Old 30th January 2013 | Show parent
  #21
Gear Nut
 
🎧 5 years
Quote:
Originally Posted by DanDan ➑️
I see a lot of subby rumble. Traffic?
Although the road is 250 feet from my house. It could have been a transport truck.
Old 30th January 2013
  #22
Gear Guru
 
1 Review written
🎧 15 years
Short

Very early indeed Jim, but so loud, only 6dB below the wanted speaker sound.
DD
Old 30th January 2013 | Show parent
  #23
Gear Nut
 
🎧 5 years
Quote:
Originally Posted by DanDan ➑️
Very early indeed Jim, but so loud, only 6dB below the wanted speaker sound.
DD
What time stamp is it found on the ETC graph? 4.7 ms?
Old 30th January 2013 | Show parent
  #24
Lives for gear
 
jim1961's Avatar
 
🎧 5 years
Quote:
Originally Posted by umarekawaru ➑️
What time stamp is it found on the ETC graph? 4.7 ms?
432us

or

.432 ms (less than 1ms) (see the -6db hump?)
Old 30th January 2013 | Show parent
  #25
Lives for gear
 
jim1961's Avatar
 
🎧 5 years
Quote:
Originally Posted by DanDan ➑️
Very early indeed Jim, but so loud, only 6dB below the wanted speaker sound.
DD
I think the thing to keep in mind for extremely early reflections is that their flight path is barely longer than the direct signal, meaning their magnitude will not be diminished noticeably by distance. So in this respect, I expect early reflections to be loud.

If you were to slice the the ETC into 1 octave bands, I think you would find that the 432us reflection to be of a narrow frequency range (probably peaking at 2k-8k) and nearly equal to the direct response. The reason it shows -6db is only because of the averaging going on in full bandwidth ETC's. In the 4k range (or whatever range the reflection is actually occurring), I bet its in the 0db to -2db range in actuality.
Old 31st January 2013
  #26
Gear Nut
 
🎧 5 years
Speaker Measures

Seems right because I took close proximity measurements of the left speaker. Same result no?
Attached Images
File Type: jpg LowVolume OneInch.jpg (90.0 KB, 289 views) File Type: jpg WaterFallLowVolumeOneinch.jpg (87.6 KB, 336 views)
Attached Files
File Type: aiff LowVolume OneInch away.aiff (6.00 MB, 115 views)
Old 13th February 2013
  #27
Gear Nut
 
🎧 5 years
Conclusion

I removed the brown desk modules.

After lots of experimentation, I cleaned up the Freq Resp to within a 13 dB window ( +/- 6.5 dB ). Not sure how to interpret these last ETC and waterfall. Your previous input tells me it's good enough for this sized room. Can't expect perfection as it serves as my bedroom after all. The beige dresser at the back must stay.

Thanks for your input guys. This community is awesome.
Attached Thumbnails
Room Measurement Results - good?-freq-etc-lspkr.png   Room Measurement Results - good?-waterfall-lspkr.jpg   Room Measurement Results - good?-freq-etc-rspkr.png   Room Measurement Results - good?-waterfall-rspkr.jpg  
Attached Files
File Type: aiff Imp Resp LSpkr.aiff (6.00 MB, 114 views)
Old 24th February 2013
  #28
Lives for gear
 
AwwDeOhh's Avatar
 
🎧 10 years
Look to me like you have a bit of 60Hz hum, though i've seen worse
I assume you're in the USA? (US power is @60Hz UK is @50Hz)

Room Measurement Results - good?-gs_rew_look.jpg

You may look at 'ground loop' or 'earth loop' solutions for more info on how to tackle it.
Old 24th February 2013
  #29
Gear Guru
 
1 Review written
🎧 15 years
Graph

The low threshold on your waterfall is -75dB. That seems extremely low.
Also if you increase the length of the 'Window' setting to the same length of the Waterfall if necessary or nearly so, then those cut-off LF bloops will clear up.

DD
Old 25th February 2013
  #30
Lives for gear
 
AwwDeOhh's Avatar
 
🎧 10 years
Right, it was extended to show that the 60Hz continues at a constant rate no matter what the window length. Maybe i'm reading that wrong though, but the 60Hz, while not too crazy in amplitude -is constant.
πŸ“ Reply
Topic:
Post Reply

Welcome to the Gearspace Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…

Forum Jump
Forum Jump