Room Eq Wizard (REW) Room Acoustic Measurement


#1

I’m looking to set up the hardware needed to use the REW software. I just ordered a miniDSP UMIK-1 Omni-directional USB Measurement Calibrated Microphone. I started to digest the REW literature (set up) and have the laptop output choice of HDMI connection or 3.5mm headphone jack. I have a PSA DMP, PSA DS DAC, and PSA BHK250 components. I’d like to understand the connection from laptop to DAC or Amp. Can I use the HDMI laptop output to DAC I2S or take the laptop headphone output and run it straight into the BHK250 amplifier after removing the XLR connection from the DAC?


#2

This should get you started. https://www.minidsp.com/applications/acoustic-measurements/umik-1-setup-with-rew

Here’s a relatively simple use of REW but I found it helpful to work through and my subs are in better phase with each other and my stand mounts as a bonus.

https://www.minidsp.com/applications/auto-eq-with-rew/measuring-time-delay

Once you’ve got the hang of measurements - I highly recommend Thierry’s service - https://www.homeaudiofidelity.com/


#3

brett66 - OK, let me start again. Setting up the REW with a UMIK-1 (USB) mic is very easy if you have an AV receiver or preamp that’s the BHK250’s source; however, I do not. If I had a turntable, very easy; I do not. I have a PSA DMP, PSA DS DAC that is the BHK250 amplifier input. So, the question becomes, how do you close the loop on the computer control of REW stimulation to the 2 channel stereo. Usually, this is accomplished by laptop HDMI or 3.5mm headphone jack output to AV receiver or preamp; however, I don’t have an AV receiver or preamp. Another approach would be using source material (SACD or CD) with PSA DMP and the laptop UMIK-1 (USB) mic to measure the source material. So, how do I hook up the laptop to the DMP, DS DAC, or BHK250. I could easily connect the laptop 3.5mm output jack to the BHK250 amplifier after removing the DAC input; however, I run the risk of allowing the computer to overdrive the speakers. SO, have you ever configured this mic with a laptop in this configuration is what I’m looking for… While waiting for someone to provide feedback, I’m going to look at renting a preamp with I2S output that would occupy the 2nd channel of the I2S (PSA DS DAC) so I can then have a closed loop for laptop control and measurement. Does that make sense?


#4

Connect pc running REW via USB to dac. You want the pc to act as a source into the dac in place of the dmp.

I would NOT connect pc analog to BHK amps. If the levels are OK it will work but if not you run the risk of killing a driver.

REW Cabling and Connection Basics-rew-connection-usb-soundcard.jpg

https://www.hometheatershack.com/forums/spl-meters-mic-s-calibration-sound-cards/10001-rew-cabling-connection-basics.html


#5

Brett66 - Yes, though the same thing till I read the REW setup.


#6

Hmm, perhaps the last time I used REW I still had an Oppo with HDMI in…sorry.

I also had one of these in the past to extract HDMI audio and output SPDIF.


#7

Brett66 - Yes on the direct PC to BHK250 connection. I think I am going to try the USB port output and see if I can work it. I used the REW signal generator output Blue Tooth to my Bose system and it worked fine. I will try the USB connection.


#8

Brett66 - thanks on the HDMI to optical. I could use that for the DAC input the form of optical cable output of the Jtech.


#9

I seem to recall REW won’t output audio on USB, which fits with requiring HDMI or analog. The converter is cheap and works as expected. I just ordered one cause I realized I can’t refresh my convolution filters with out it.


#10

Brett66 - Thank you so much for your help. I will run the laptop HDMI output to the J-Tech audio extractor, then TOS Link to the DAC input. I ordered the J-Tech and TOS LINK cable for MON (09/10/18) delivery. The USB mic will arrive on THU. I have also just bought a pair of REL subs for my system and modified my acoustic treatments. I will now measure the room and move the ASC isothermal bass traps around the room to give me the best performance with the subs added. Since the music room is 11ft X 21ft X 10ft, I ended up going with a pair of the REL S3/SHO. I will be using the REW SW and setup to tune the placement of the bass traps. I added the bass trap shelves in the corner to pick up the bass traps and run them from the shelve to the ceiling. The additional (2) 3ft traps I put together and thinking about adding them to the top of the rack since the additional LF pressure point is midway on the attack wall. However, I will be using the REW SW to determine the best placement. I also might add a few diffusers., we’ll see. I also pulled all the acoustic treatments out of the music room and performed a SUMIKO master speaker placement procedure with just the SF Guareni Evolution speakers. This procedure moved the speakers out so now the sound stage width is about 8ft and sitting 9.5ft from the speakers. I also used the Chesky test CD to make sure the 3D imagining was great. These speakers are amazing.


#11

I find the subs work better mid wall out of the corners. I also find getting the everything from between the speakers helps depth especially.

Take your time in bite sized chunks with REW. There’s a lot and learning what the data is conveying can be involved.

If you have the ability to playback convolution filters, I would strongly encourage you to experiment with them. They ‘fix’ my room as I’m not able to fully treat the lower modes in particular and resolve my symmetry issues. Your room looks very symmetrical which is very good.


#12

Brett66 - Using the Chesky Audiophile test CD tracks 10 through 26 demonstrated the amazing 3D imaging of these SF Guareni Evolution speakers and this system. After the SUMIKO master speaker placement, the speaker’s bass coupled nicely in the room. Slight movements of speaker matter and it takes hours of moving the speakers to get that “spot”. Since these speakers weigh over 100lbs (book shelf) each, I used towels for moving them around and also increments of partial inches. You have to remove all the acoustic treatments to fully engage the room with bass. I used Wasserman’s Duet CD with the Ballad song playing over and over and my wife out of the house. This song has bass notes between 40+ Hz and 60+ Hz; however, you have to really crank the system to engage the room. The female voice helps as much as the bass notes. It is a perfect combination to get the speaker bass coupling to room and the toe-in and rake established with her voice. Separating the speakers further developed a much better sound stage. The speaker toe-in is not directly at the viewer; off just enough to create an amazing sound stage. The really cool thing about these speakers is their 3D imaging and their ability to get lost in the sound stage. I never hear the music coming from the speakers. Also, another great thing about them is their sweet sound that I can listen to all day. I never get ear fatigue; listening to hours of many different types of music. The only down side to these speakers is they roll off at 40Hz so the really low end needs help. I chose the REL S3/SHO because they are matched to the SF Guareni Evolution speakers. I was going to go to a pair of REL G1 MKII subs; however, thought that would be overkill for such a small room. Sub placement will start in the corners; however, they will more than likely end up just behind the SF speakers out from the corners. Also, it will be a lot of fun tuning the sub crossover. I am aiming for the lowest crossover; however, ear and measurements will tell.


#13

Brett66 - I just ordered a mic stand; the one that comes with the miniDSP UMIK-1 Omni-directional USB Measurement Calibrated Microphone is a table top and would be difficult placing it where I would be seated. I am really going to get into this measurement approach. I will baseline the room with zero treatments; then very carefully add acoustic treatments. I want to really understand diffusion and extending the room size. I think I’m going to also pick up some books on acoustics and start to really dig deep. Once I have the measurement method researched, implemented, and validated, I can then debunk a lot of tribal knowledge. In addition, I think I’m going to build my own diffusers and test them out. This is going to be a lot of fun. I figure it will take me at least a year of R&D, theory, measurement validation, implementation… this is going to be fun…


#14

Brett66 - I just finished designing a couple of vertical diffusers for my music room. I wanted to keep the BW wide so the depth was between 9in (P7) and 12in (P13). I’m using P7 (48in X 17in X 9in) for the attack wall and P13 (48in X 30.5in X 12in) for the side and rear walls. One on each side wall and two on the rear wall. The front diffuser BW is between 305 Hz & 4124 Hz and the side and rear wall diffuser BW is between 370 Hz & 4125 Hz. I will be building these this fall.

Attach Wall:

Side & Rear Wall:


#15

Brett66 - Just received my J-Tech convertor from Amazon (2 days from order to door). Since the convertor is plug & play, it took me about 2 minutes to start listening to TIDAL streaming from my laptop to J-Tech convertor through HDMI cable, then J-Tech output to PSA DS DAC input using 12ft TOSLINK optical cable. Now I have another source. Next I will set up the USB mic with laptop and mic stand. I should be measuring by the end of this week. I wanted to thank you for your help, it worked as advertised and very easy to set up.


#16

I bought one too, arrived next day. I want to take my receiver hdmi output and send it to DS, as well as for use with REW.


#17

Brett66 - This was so easy to hook up. Next step is the USB mic, then I will start measuring. I am not going to build the diffusers for at least a few months. I want to really get deep using the REW software. I might need some help with the analysis. I also bought the Acoustic Handbook for theory…


#18

Brett66 - I just installed the subs. Holy crap! My wife says the music can now be heard well on the outside on the other side of the house. It shakes picture frames and anything with resonance rooms away. I’m not a sub fan and always bought full range speakers. These REL sub pair add a low end woofer to the SF Gaureni Evolution speakers and keep up with them very well. So, I was hearing low end reverberation in the room so I added the ASC isothermal bass traps to the attack wall corners and man does it help. Bass is extended, tight, and feels like I just added a nice woofer to each main speaker. Adding a sub is not about the bass bump, it’s about filling in the low end presence. Now the sound stage has low end presence. I was just listening to Queen’s greatest hits and they love the low end. These REL subs are magnificent.


#19

Brett66 - Here is the room showing the cabling and more of the speakers.


#20

I spent some time with REW yesterday, pretty happy with the result. My decay times aren’t measured in milliseconds though…the small space rings. Not much I can do beyond what I already have, just have to dial it back sometimes.