Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 23

 

In case anyone needs to download ASIO4ALL, I have uploaded a copy to Dropbox:

 

 

http://dl.dropbox.com/u/78476446/ASIO4ALL_2_11_Beta1_English.zip

 

Ok, I got my new cable and can confirm that when using my laptop and REW to generate the test tones, my AVR is only outputting to the center + sub in PLIIx mode and in stereo with my Y adapter cable it's outputting to the L/R + sub.  Suffice it to say I think I had a blonde moment on why my previous setup was not outputting correctly.  I was expecting to be able to output the mono signal to the L and R channels independently without disconnecting the cable at the AVR.

 

Is there any interest in seeing a comparison between OM and the latest beta of REW using the OM Mic and .omm calibration file?  If so, any particular measurement as I have everything setup at the moment?

 

EDIT:  @AJ, I think maybe the differences I was seeing between the guide and my REW screens is just a software revision difference.  I was able to match everything up once I got the test tones sorted.  Here's a screen grab of my preferences:

 

Thank you very much AustinJerry, the site is still down.

Bill

Here is the response on HTS from John to my question I posted earlier today.

'You don't need to match input and output when using a USB mic. Do the tests with the test signal at about 75 dB at the listening/measuring position.'

So if you have the USB mic you don't have to level match the IN/OUT, which is good since I would have blown something if I had to get that to match

Now I have to wait for another quiet moment in the house to try again.

So I guess Jerry for your guide, the matching piece does not seem to apply for the USB mic, unless I am misunderstanding John at HTS.

I guess J do you concur?

I read the thread at HTS as well, and agree with you. Recall that the current guide has a disclaimer that the guidelines are likely to change once we have USB mics to test with. I am expecting to receive mine late next week.

Looking at your setup screen, I'm confused. Isn't the OmniMic a USB mic, and shouldn't it be configured with ASIO? I don't know, I'm just asking.

Just to make sure everything is working OK, why don't you take a sweep measurement 20-20kHz, and post the results with 1/6 smoothing.

I asked about ASIO in an earlier post and got the impression that if I wasn't using HDMI then I didn't need it (i.e. the ASIO4ALL driver). I was confused as well. I did post some results here:

http://www.avsforum.com/t/795421/official-audyssey-thread-faq-in-post-1/59400_100#post_22883961

These are only showing 15-300Hz but I still have the mdat files and did full range measurements. These also show 1/24th smoothing. Sorry I couldn't just post here...limitations of rich text editor and my iPad make it difficult to post images.

Is it a must to install ASIO4all?

I'll be doing REW on a Dell Studio 15 laptop which has IDT 92HD73C High Definition Audio codec and onboard ATI Radeon HD4570. My mic will the RS SPL meter.

If I just plug a 3.5mm to stereo RCA cable from my laptop 3.5mm out to both L+R of my AVR AUX IN, when the REW is outputting its sweep test tone, is it testing both the L+R together?
The input selection (left or right) in REW preference window is for mic input channel selection, isn't it? where is the output channel selection?

The connections are covered in the guide. Yes, you can use the headphone output jack for REW. The RS SPL is really only good up to about 5kHz. If you want to measure a full 20-20kHz, then you need a calibrated mic.

i

The new REW beta 13 is supposed to add support for the OM USB mic. Are there instructions over on HTS on how to configure it? I don't know, and I am hoping you do the research so we can add your results to our knowledge base here.

If you get a chance, post your 20-20kHz measurements here so we can take a look.

 

Ok, I'll post the full sweeps tomorrow as they're on my laptop.  As for the new REW beta, it recognized my OM Mic right away and asked if I had a calibration file.  I pointed it to my .omm file and then followed your guide (skipping the ASIO stuff) and just started measuring.  As I alluded to in some earlier posts, I was getting confused with the guide because nothing seems to work in my setup if I choose ASIO in the configuration settings of REW (presumably since I didn't install the ASIO4ALL driver).  In any case, I'm sure you'll be able to tell much more tomorrow when I post the mdat files.

Welcome to the perplexing complexity of REW....

 

Yep - that is me to a T also, Jerry. I want to get the best I can get in my room, but there is a limit on what I am prepared to try to learn. There is just NFW I am going to read a dozen text books, but I am more than prepared to learn from the  experience of other members and also from the distilled experience of the true experts like J, Nyal etc.

+1 to that!

Can someone please explain to me how using HDMI compares to using the regular RCA to 3.5mm head phone jack in my laptop? I currently have an old Samsung laptop that has no HDMI connection, but I wouldn't mind buying an external HDMI equipped sound card. Speaking of which, can anyone recommend one?

I realize that this is probably explained in the previous write-ups, but I am pressed for time and was hoping someone could give me the cliff notes version to my answer.

Thanks!

When using the Java drivers REW outputs the test signal on both left and right channels. With ASIO drivers channels are fundamentally mono, so the channel used for the test signal and the channel used for a loopback timing reference are selected separately. Even if you are not using a loopback connection the ASIO timing reference output setting can be used to place the test signal on a second channel.

I don't believe there are any external soundcards with an HDMI output. HDMI is both a video and audio output device.

 

An HDMI connection is not a requirement towards obtaining meaningful REW measurements.  Using the headphone output on the laptop, or the standard RCA output from an external soundcard, will work just fine.

 

What does HDMI add to the equation?  HDMI, when used on laptop hardware that supports a full 7.1 audio output, will allow you to test each channel individually including the surround channels.  I have stated in earlier posts that I believe being able to test the surround channels has marginal value.  With a normal (non-HDMI) connection, you can conduct the following measurements:

 

- Left channel (with or without the subs)

- Right channel (with or without the subs)

- Left+right channel (with AVR in Stereo mode, with or without the subs)

- Center channel (with the AVR in PLII Cinema more, with or without the subs)

- Subs only (by turning off or unplugging the main speakers)

 

So, you have a full suite of tests without using HDMI.  HST, if you are inclined to purchase an external soundcard (which is not required if you are using a USB mic), then purchasing one that has an HDMI connection would be a small plus.  My internet search for "external USB soundcard with HDMI" produced a number of hits.

Quote:
Originally Posted by Theresa View Post

Ok. After many tries it now recognized my Omnimic and HDMI output. Must now experiment. Unquote

Quote: You may not need another mic then Theresa - the ver 2 of OM has a cal file that REW can use. Unquote

Thank you, that is good news.

 

@AJ:  I think JohnPM has answered our question about the difference between Java and ASIO drivers.  It appears as though not having an HDMI cable makes using the Java drivers one less (possible) step in the process.  Not sure if there's any added benefit to installing it?  Therefore, I believe my setup is fine except for the fact that I skipped the calibration (step 5) in your guide as it got lost in the ASIO (step 4) stuff.  One suggestion might be to add quick links to the beginning of each step in the table of contents.  Might not seem like a big deal now but I suppose once this document grows it will come in handy.

 

Here's a Yousendit link (EDIT:  Link removed due to incorrect mic orientation) to my mdat files (pre mic calibration as I've just been informed I have other plans today!).  Also, here's a graph (1/24th smoothing) of the post Audyssey, full range for LCR + Sub (independently measured) plus sub only:

 

Edited by jkasanic - 1/29/13 at 7:08am

You (in particular) might want to consider a UMM-6 mic from CSL as it comes with calibration files for more than just one mic orientation.

jkasanic, don't know about others, but the Yousendit link doesn't work for me.
Edited by mogorf - 1/27/13 at 12:34pm

^^^ doesn't work for me either.

Try again...editing rich text and HTML on an iPhone or iPad really sucks! I had http://https:// in the link.

Not sure how Yousendit works these days but I think there is an option to leave a copy on the server when you hit download. I guess you should check this option so it can be downloaded multiple times.

A sweep of the center channel using Omnimic:


The dips between 90-100Hz and 300-400Hz probably need room treatment to manage them. The 90-100Hz dip looks like a crossover problem but it's not, it stays there regardless how the crossover is set.
Edited by Theresa - 1/27/13 at 1:53pm

 

If I understand you correctly, you are saying that if you are not using HDMI, then use Java instead of ASIO, and skip the download/install of the ASIO4ALL driver.  I agree. 

 

However, I want to state it one more time.  The purpose of this thread is to simplify REW by using USB mics and HDMI connections.  There are a number of other possible ways to configure REW, including the "legacy" way that I have been using for several years, but we cannot develop procedures for every flavor in this thread.  The fact that you are up and running using Java is fine, and will allow you to contribute measurement graphs and benefit from room improvement suggestions down the road.

 

Regarding your suggestion to use quick links in the guide, I already have.  If you open the Guide PDF in either IE, or on an iOS device like an iPad, and then click one of the lines in the Contents section, you will be taken directly to that section.  Please test this out and confirm that it is working for you.

 

And finally, I was able to download your REW measurements file after you corrected the link.  I plan on looking at it later.

+1. We have our hands full with that alone. Of course, as you say, there is nothing to stop anyone posting their REW graphs for comment and analysis later, once we are all up and running, regardless of whatever REW setup method they employ.

WOOT!  Just got an email from Herb - my UMM-6 has been despatched. US Mail - usually takes at least a week...

Mine too. Let the games begin!

Jerry, with all due respect (and I believe this has been touched upon in previous posts as well), shouldn't we at least consider the USB mic and HDMI mutually exclusive items for the benefit of those following this thread? I would contend the ability to use a USB mic with REW is far more significant than the benefit of using ASIO for independently measuring each channel (especially in terms of the ease of setup as this seems to have generated most of the renewed interest in REW particularly for those that fled to OM due to the relatively difficult setup issues with REW). I believe you've stated on more than one occasion that the latter provides very little real benefit to the user and I would contend makes the plug and play (oops did I just say that?!) of a USB mic with REW more complicated. Since using a USB mic without ASIO is really just a subset of using the mic with HDMI, I don't see too much harm in saying something in the guide to the effect that if you don't have HDMI then the next part is optional. Finally, if you do decide that the guide should be exclusive to HDMI then I would consider removing the cabling options you've shown already as that seems to contradict this position wrt HDMI. HST, I can fully respect your intention to keep the various connection options to a minimum.

In terms of the guide, sorry, I was mistaken! Links work like a charm and all 5 steps are there!

I certainly would appreciate any feedback on my mdat files! Thanks again for all of your support!
Edited by jkasanic - 1/29/13 at 7:07am