Room Measurement Tutorial for Dummies Part 2

[dorirod]

Hey, thanks! Your opinions really helped me a lot.
Today, I didn't dwell on whether the two curves were aligned. I tried REW's EQ, but unfortunately, the effect wasn't very noticeable.I think I may have been too conservative when setting the EQ in REW, which is why there wasn't much difference(the pinkish one is after EQ, and the reddish one is the original).
Thanks again for your advice.

Are you sure the EQ took effect? Maybe stating the obvious, but REW just gives you the filters, you have to apply them somewhere (not sure what you're using for that in your chain). Try making a really noticeable change, say -10dB at 1kHz, or a low pass filter that kills everything past 1kHz and see if you notice it.

 

[JW20147]

Are you sure the EQ took effect? Maybe stating the obvious, but REW just gives you the filters, you have to apply them somewhere (not sure what you're using for that in your chain). Try making a really noticeable change, say -10dB at 1kHz, or a low pass filter that kills everything past 1kHz and see if you notice it.

Oh, sorry, I just realized today that there was a problem with the output settings on my REW, which allowed me to bypass the EQ output settings in Equalizer APO.These are the results I measured after resetting the EQ and adding a smile curve (my friend strongly recommended this to me).

 

[JW20147]

REW is an excellent measurement tool! It can also offer good correction results but the learning curve for FR modification is very steep and not something that can be mastered in a few days.
I would highly suggest finding a way to introduce Audyssey or Dirac room correction into the playback chain to smooth the below 250hz curve.
The most basic approach is to use one of these semi-automated programs for the curve correction and then follow using REW to measure the
results.

I checked, and currently I can't afford the Audyssey or Dirac hardware or software. In fact, their prices exceed the price of my audio system, ha ha ha ha. But thank you very much for your advice. I will consider it when my wallet is a little fuller in the future.

 

[prasanth.nath]

@amirm how can we pursuade you for Part 3.
That document (IMO) will be more valuable that yet another dac.

 

[Sal1950]

@amirm how can we pursuade you for Part 3.
That document (IMO) will be more valuable that yet another dac.

Money never hurts

 

[viktorapo]

i want to get a microphone and measure my room properly. i currently own the RME Fireface UC soundcard so I am wondering, should I get the UMIK-1 for the sake of ease and then just in REW configure output 1+2 to RME (speakers) and input the UMIK-1? Or what's other option (besides the Behringer) in the 100$ price range.

 

[nathan]

UMIK 1 is a great option. I have heard of folk using a similar mic from Parts Express with good results as well but I don't recall the model number.

 

[Keith_W]

i want to get a microphone and measure my room properly. i currently own the RME Fireface UC soundcard so I am wondering, should I get the UMIK-1 for the sake of ease and then just in REW configure output 1+2 to RME (speakers) and input the UMIK-1? Or what's other option (besides the Behringer) in the 100$ price range.

Just get the Behringer. I don't know why you would buy a UMIK-1 if you have an interface.

 

[viktorapo]

UMIK 1 is a great option. I have heard of folk using a similar mic from Parts Express with good results as well but I don't recall the model number.

Would my setup work though?

Just get the Behringer. I don't know why you would buy a UMIK-1 if you have an interface.

a lot of people saying and providing data with the inaccuracy between the behringers, will make me always think if what im measuring is correct or not

 

[levimax]

Would my setup work though?

a lot of people saying and providing data with the inaccuracy between the behringers, will make me always think if what im measuring is correct or not

People seem pretty happy the these calibrated MIC's, they sell several different models which they supply the calibration file for https://www.cross-spectrum.com/measurement/calibrated_dayton.html If you like overkill good tools that will last a lifetime and give great performance and satisfaction every time you use them take a look at Earthwoks M20 or M23.

 

[flightops]

I've been using an Eversolo EM-01 with REW. The EM-01 is roughly half the price as a UMIK-1 (at least it is for here) and you can buy it right off amazon and have it delivered right to your door: https://www.amazon.ca/dp/B0DP9VK96R?ref=ppx_yo2ov_dt_b_fed_asin_title

Downloadable calibration files (keyed to the serial number) for horizontal and vertical orientations.

I'm just using an inexpensive amazon mic stand, which is surprisingly heavy and sturdy: https://www.amazon.ca/dp/B0DB5NVC2V?ref=ppx_yo2ov_dt_b_fed_asin_title

The mic "clip" from the Eversolo screws right into the end of the boom.

I'm all analog though (stereo 2.1) so for me, it's solely used for measuring and that's it. the Eversolo seems to be working well so far. I've already made significant improvements in the room's SQ with it.

 

[WerT]

when can part 3 be expected?

never ever

 

[Linnie]

I thought I’d share my first steps into REW. Maybe someone find my impressions helpful.

For my personal approach to REW I followed Amir’s advice and did not bother much about configuration or calibrating and started „playing“ as he describes in his fabulous dummy tutorial.

After I successfully made some measurements using my notebook’s loudspeakers and microphone, I grabbed out some external gear to see what happens.

This was my setup: Notebook with REW running, a Behringer UCA222 USB card, a 20+ years old RadioShack Sound Level Meter for measuring and a 30+ years old Trust PC speaker as source.
I used the headphones out of USB card to connect the speaker because I had no adapter at hand. Worked anyway. The Sound Level Meter has an analogue output I connected to an input channel. And no, I didn’t want to use my better gear for playing around in the first place.

Measurements were taken more or less the way you see it in the picture. I made some with the Sound Level Meter and some with the notebook microphone. Sound Level Meter was lying about 2 feet away from the speaker facing in it's direction, Notebook mic about 1 ft away. Speaker wasn’t moved. This is what I got:

Sound Level Meter measurement is green, Notebook mic is red.

Two things I find remarkable:

• How similar the measurements are in general considering the differences in measuring angles, devices and distances
• This seems to be a pretty nice frequency response for a decades old,cheap PC speaker!

During my proceedings I had to face some challenges I want to mention in case they might be helpful to other beginners:

• battery of Sound Level Meter was empty
• spare battery (ready until 2011) was empty, too
  
• Windows 11 would recognise the Behringer card but not necessarily select it automatically as input and output device. You can select that manually via properties > system > sound
• When checking levels in REW, the program frequently complained about input level being too low. Following REW help, I dialed up input gain in Windows sound properties (and created an unintended feedback loop, so better proceed carefully..)

Initial output in REW does’t look pretty:

<IMAGE>

I had to do some reading until I found out that the nice looking graphs normally presented here are created by „phase smoothing“. You can choose this in REW menu in the „Graph“ tab. 1/12 octave smoothing looks much more to what we're used to:

<IMAGE>

If you publish a Hi-Fi magazine, you might want to make it look even more friendly with 1/3 oct smoothing:

 

[janbth]

A good start! Some comments about your plots:

• The top plot looks good - good smoothing, good choice of span on the axes. Of course, the speaker is what it is.
• Your three bottom graphs:
  • Use Var smoothing = no smoothing in the bass, some smoothing in the highs. This is the best general-purpose smoothing for graphs.
  • X-axis should go from 20 Hz - 20 kHz, or maybe start at 10 Hz, but below 10 Hz is not relevant.
  • Y-axis should span about 50 dB. This is conventional and doesn't compress the data.

 

[Sal1950]

This was my setup: Notebook with REW running, a Behringer UCA222 USB card, a 20+ years old RadioShack Sound Level Meter for measuring

KOOL. That's the original 33-2050. I've got the same one purchased back in the later 1980s and has been used many many times over the decades.
Mine still works perfectly but YES you do have to replace the 9 volt battery on occasion.
Pre-computer days, I can still remember using vinyl sources with tone generation tracks and graph paper to create VERY crude response graphs charts.
Oh my brain hurts just thinking about.
God Bless modern tech