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Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 29

post #841 of 9564
Quote:
Quote:
Originally Posted by AustinJerry View Post

BTW, the mic holder has a small plastic adapter that allows the holder to fit onto either a large threaded connection (like on the Pro boom mic), or a small threaded connection (like a camera tripod).  Nice.

 

BTW #2:  the supplied USB cable is 10 feet long.  Not real long--may need an extender.

 

10 feet is too short for me. Any recommendations for a USB extender - max length etc?  I assume they are, like other cables, all the same so long as they work. I'd need another 10 feet - I guess that won't affect the measurements in any way, or will it?  Do I need a powered extender?  Maybe one for the Setup Guide, Jerry?

Gear mentioned in this thread:

post #842 of 9564
Quote:
Originally Posted by JohnPM View Post

I would strongly advise people not to attempt measurements 60dB above the background noise level in their environments. Measuring at high levels risks damage to equipment, hearing and relations with your neighbours and pushes equipment out of its linear range, increasing distortion and degrading measurement quality.

Measurement software can see well below the acoustic noise floor of your room. The important signal-to-noise (S/N) ratio in measurements is the S/N of the recovered impulse response. To see that, open the Impulse plot with the vertical axis set to dB FS - by default this plot is normalised, which means the peak value is at 0 dB FS, and the noise floor of the impulse response will be apparent when zoomed out so the plot spans a second or so - if the noise floor is at -50 dB FS, for example, the measurement has 50 dB S/N. If the impulse response S/N is below 40 dB or so you may start to see noisier frequency response plots and the floors of waterfalls and spectrograms will start to show more noise, but the measurement still remains useful.

If the S/N of the impulse looks poor and you are using a microphone and preamp or a line input adjust the input gains to keep the signal at a good level, with the peak during a measurement getting to around -10 dB or so (this is shown on REW as the "Headroom" figure when you measure, it should not be too high). USB mics will usually show lower levels as they tend to accommodate wider input ranges, but should still give good impulse response S/N values.

The best way to improve S/N in the measurement is to use a longer sweep, each doubling of sweep length improves S/N about 3 dB. If you are already at the maximum sweep length, try multiple sweeps, though the improvement from each doubling of the number of sweeps is usually not quite as much and some soundcards do not maintain synchronisation between sweeps, causing invalid measurements (evident in multiple peaks at or near 0 dB FS in the impulse response, one per sweep).

I 100% agree. I think the suggestion to measure at 90db or so is rather dangerous. People don't realise how loud a constant 90db is.

And it is unnecessary (depending on what you are measuring).

I currently live on a rather busy road so the noise floor is much higher than I would like. I also have a new baby.

Yet the FR response from my speakers as seen by REW doesn't vary whether I use 70dB or 90db. Occasionally I remeasure because of an obvious bus induced false reading. When I get the warning from REW about S/N I always save the measurement to compare. Not much difference.

Even waterfalls and ETC curves don't show drastic differences when measured in peak hour or at 3AM.

Admittedly I have active dipoles which don't like really deep bass and don't have any protection for individual drivers, but I try not to go above 75db. The ARC in my Anthem prepro picks a similar level.

As an aside, I haven't checked this thread for a while, but it is disappointing to see it become polluted with arcane hobby horses. They may or may not be founded in fact, but I thought this thread was to help beginners take the leap into measuring their room and speakers.

95% of 'audiophiles' have no clue what the real response of the the speaker/room combo is. The coolest thing about REW is the democratisation of what is required to find out.

If this thread can help people take a simple frequency response, then use the RTA to position their speakers, then check what their chosen roomEQ has done we will have provided a very valuable service.

The ETC/waterfall/whatever stuff is a distraction.
Edited by Steve Dodds - 1/31/13 at 3:58am
post #843 of 9564
Quote:
Originally Posted by djbluemax1 View Post

Yep, place the stand on the floor in front of the seats. That stand will easily extend to position the mic where your ears would be in the seat.

A couple of added tips:
1) if you have suspended flooring, vibrations can and will travel through the floor and up the stand to the mic (especially in the lower octaves). This can result in anomalous results with measurements and Audyssey calibrations (short sub distance measurements post Audyssey are one example).

You can purchase mic stand vibration insulators made to go on the tripod feet to reduce that. I found that making my own from car wash sponges works well especially to insulate the mic from the stand. Simply use scissors to cut a slot to slide the sponge over the end of the boom (no need to get the boom to camera mount adapter piece). Taper the end a bit with the scissors and tape the Audyssey mic to the sponge ensuring that the tape does not directly connect the mic and boom.

Look at various sponges available at your local store. You'll want the kind that's 3-4" thick, 5-8" wide and 8-10" long. Don't get one that's too firm as it can still transmit vibrations. If you get one that's too soft, it may not support the mic very well. For the REW mic, you can cut a slot in the end for the boom, and another slot to slide the mic into that will hold it upright. You'll need to set up the stand to get the 2nd slot right, but sponges are cheap.

Although we're aware that for new users, the "Audyssey killed my bass" comment is often due to not being used to flat bass, when I did an Audyssey calibration on sprung/suspended flooring, I noticed that the bass had been significantly reduced. The vibrations through the floor and mic stand led Audyssey to believe that there was way more bass than there actually was. Insulating the stand from the floor and later, the mic from the stand cured this.

 

 

There are a couple of suggestions for the foam absorption feet in the Audyssey FAQ. I have dug out the relevant section in case anyone needs to source these things:

 

 

If your floors are the wooden suspended sort, you may want to place the legs of the mic stand on some sort of absorber to minimise the chance of spurious bass signals entering the mic via the floor and the stand itself. These are ideal for most people:

post #844 of 9564
I use a 5m extender and a 2m cable with no issues, although I believe the USB standard specifies 5m maximum. It has a little dongle which is supposed to help with the longer length.

http://www.ebay.com/itm/400376694504?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

IMHO it is like other digital cables. It will either work or it won't.
post #845 of 9564
Anyone tried the minidisp UMIK1 mic on Windows8? will it work?
How about REW on Windows8?

Just asking cos all the new laptops come preloaded with windows8.
post #846 of 9564
Quote:
Originally Posted by Steve Dodds View Post

I use a 5m extender and a 2m cable with no issues, although I believe the USB standard specifies 5m maximum. It has a little dongle which is supposed to help with the longer length.

http://www.ebay.com/itm/400376694504?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

IMHO it is like other digital cables. It will either work or it won't.

 

This site, which has an official sounding name, says 16ft is the max distance according to the spec:  http://www.usbcable.com/usbbasics.htm.  There is a page that lists some specialized extender cables, including one similar to the one Steve has recommended, at various prices.

 

I am concerned for several reasons.  First, this adds another layer of complexity (and cost) to what is supposed to be a simple solution.  And second, I am worried that extender devices might add noise to the mic signal.  When I was making some initial measurements yesterday, the noise floor of the measurements was higher than I have been seeing with the standard mic.  Not sure what was causing it-I need to get that sorted out today.

post #847 of 9564
Quote:
Originally Posted by Skylinestar View Post

Anyone tried the minidisp UMIK1 mic on Windows8? will it work?
How about REW on Windows8?

Just asking cos all the new laptops come preloaded with windows8.

 

I haven't tried it, nor do I plan to.  I have evaluated Windows8 on a separate PC, and I don't like it.  Perhaps you could blaze the trail and report back?

post #848 of 9564
Quote:
Originally Posted by kbarnes701 View Post

10 feet is too short for me. Any recommendations for a USB extender - max length etc?  I assume they are, like other cables, all the same so long as they work. I'd need another 10 feet - I guess that won't affect the measurements in any way, or will it?  Do I need a powered extender?  Maybe one for the Setup Guide, Jerry?

The limit for USB cables is 5 meters so an extra ten feet would be too much. There are "repeaters" for USB though that would probably work. I got my USB extension cables (2 meters) from monoprice but since your in the UK there is probably an equivalent cable company over there.
post #849 of 9564
Quote:
Originally Posted by AustinJerry View Post

I haven't tried it, nor do I plan to.  I have evaluated Windows8 on a separate PC, and I don't like it.  Perhaps you could blaze the trail and report back?

Yes, I dislike Windows 8 so much that I'd switch to a Mac before I'd adopt it. You could always buy a copy of Windows 7 and install it on a new laptop.
post #850 of 9564
Quote:
Originally Posted by Steve Dodds View Post

I use a 5m extender and a 2m cable with no issues, although I believe the USB standard specifies 5m maximum. It has a little dongle which is supposed to help with the longer length.

http://www.ebay.com/itm/400376694504?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

IMHO it is like other digital cables. It will either work or it won't.

 

Thanks Steve. An additional 3m would be plenty for me. I will order one now so that I can hit the ground running when my mic arrives.

post #851 of 9564
Quote:
Originally Posted by Theresa View Post

Quote:
Originally Posted by kbarnes701 View Post

10 feet is too short for me. Any recommendations for a USB extender - max length etc?  I assume they are, like other cables, all the same so long as they work. I'd need another 10 feet - I guess that won't affect the measurements in any way, or will it?  Do I need a powered extender?  Maybe one for the Setup Guide, Jerry?

The limit for USB cables is 5 meters so an extra ten feet would be too much. There are "repeaters" for USB though that would probably work. I got my USB extension cables (2 meters) from monoprice but since your in the UK there is probably an equivalent cable company over there.

 

5 meters is 16 feet, Theresa ;)  10 feet is 3 metres.  It seems from the various replies that I can extend by 3m without any worries. I could manage with the 10 feet cable the mic comes with since I bought a 25 ft HDMI cable, but it would be easier for me if I had another few feet of mic cable. Even another 2m (6.6 feet) would be OK.

 

EDIT: Ah, I may have misunderstood you. I apologise. I think you mean that 10 feet added to the original 10 feet is too much, as the max length should not exceed 16 feet.  How complicated even the simplest of things can so easily become...


Edited by kbarnes701 - 1/31/13 at 4:38am
post #852 of 9564
Quote:
Originally Posted by Theresa View Post

Quote:
Originally Posted by AustinJerry View Post

I haven't tried it, nor do I plan to.  I have evaluated Windows8 on a separate PC, and I don't like it.  Perhaps you could blaze the trail and report back?

Yes, I dislike Windows 8 so much that I'd switch to a Mac before I'd adopt it. You could always buy a copy of Windows 7 and install it on a new laptop.

 

LOL!!!  Yikes!! It's THAT bad huh? :) :)

post #853 of 9564
Quote:
Originally Posted by djbluemax1 View Post

1) if you have suspended flooring, vibrations can and will travel through the floor and up the stand to the mic (especially in the lower octaves). This can result in anomalous results with measurements and Audyssey calibrations (short sub distance measurements post Audyssey are one example).

Max

ETC can be used to identify this behavior as well! how about that!
post #854 of 9564
Quote:
Originally Posted by AustinJerry View Post

One would think so.  However, you will find many of us use the Radio Shack SPL, so that may be a better choice.  For REW use, make sure the SPL has an output connection.  The RS SPL, for example, has an RCA connection that sends a signal to a soundcard or your laptop.
I looked at the RS SPL online and it doesn't look like it has an output connection. Can you give me links to SPL meters that have output connections. Preferably the most inexpensive.
post #855 of 9564
If I wanted to submit frequency measurements to experts/vendors to obtain acoustical room advice prior to purchasing room treatment products, what is the basic outline of the whole process from setup to final submission of the frequency measurement results?
post #856 of 9564
Quote:
Originally Posted by Steve Dodds View Post

I use a 5m extender and a 2m cable with no issues, although I believe the USB standard specifies 5m maximum. It has a little dongle which is supposed to help with the longer length.

http://www.ebay.com/itm/400376694504?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

IMHO it is like other digital cables. It will either work or it won't.

I've always used this 10m active (amplified) extender http://www.amazon.com/BlueRigger-Female-Active-Extension-Repeater/dp/B005LJKEXS/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=Q3U1JWA2SL3O&coliid=I36RV8BZQEHR33 with my Pro calibrations. Has always worked perfectly. Only $8.99 and free shipping with Prime.
post #857 of 9564
Quote:
Originally Posted by Stealth3si View Post

Quote:
Originally Posted by AustinJerry View Post

One would think so.  However, you will find many of us use the Radio Shack SPL, so that may be a better choice.  For REW use, make sure the SPL has an output connection.  The RS SPL, for example, has an RCA connection that sends a signal to a soundcard or your laptop.
I looked at the RS SPL online and it doesn't look like it has an output connection. Can you give me links to SPL meters that have output connections. Preferably the most inexpensive.

 

My RS meter has an output jack. Are you sure they don't these days?

post #858 of 9564
Quote:
Originally Posted by Stealth3si View Post

If I wanted to submit frequency measurements to experts/vendors to obtain acoustical room advice prior to purchasing room treatment products, what is the basic outline of the whole process from setup to final submission of the frequency measurement results?

 

I have worked with three vendors, RealTraps, GIK Acoustics, and ATS Acoustics.  With GiK, for example, I simply called and asked to speak with a consultant.  We talked in general about my room, what I thought the issues were, etc.  He asked me for pictures of the room, some specific room measurements, and I even sent the actual REW measurement data to him to analyze.  He was quite helpful, and recommended specific solutions without any high-pressure sales tactics.  I don't think you should do any specific advance work other than, of course, participate in this thread and develop your REW skills.

post #859 of 9564
Quote:
Originally Posted by Stealth3si View Post

I looked at the RS SPL online and it doesn't look like it has an output connection. Can you give me links to SPL meters that have output connections. Preferably the most inexpensive.

I recently bought a used RS meter w/ output via ebay for 12 bucks.
post #860 of 9564
Quote:
Originally Posted by Stealth3si View Post


I looked at the RS SPL online and it doesn't look like it has an output connection. Can you give me links to SPL meters that have output connections. Preferably the most inexpensive.

 

Look at the users manual here.  It clearly shows an RCA output.  However, before you get all excited, recall that with the new way we are connecting up REW, you won"t actually be using the audio output of the SPL.  I apologize for giving you wrong advice in my previous post.  I was thinking of using an SPL with the "legacy" REW connection, which involves an external USB sound card.  Now, the only use for the SPL is the microphone balancing step, and it doesn't involve an audio connection.

 

HST, there are all sorts of other ways an audio enthusiast will use an SPL, so you aren't wasting your money just for REW.

post #861 of 9564
Quote:
Originally Posted by Skylinestar View Post

Anyone tried the minidisp UMIK1 mic on Windows8? will it work?
How about REW on Windows8?
Both REW and UMIK-1 work fine on Windows 8.
post #862 of 9564
Quote:
Originally Posted by AustinJerry View Post

I don't know, and have not heard of anyone trying this.  If you find that it works, please let us know.  Just using REW with a Mac Book presents some issues, although beta 13 is supposed to provide support.  

On Mac's there is a Audio MIDI set up application in the utilities folder.
From there you can configure speakers , then there is a selection for Multi, then a drop down menu with stereo,5.1,7.1 etc

But only stereo in available. I wonder if connecting the optical to a pre amp would open the other options.

I'll have to in investigate

Athnaasios
post #863 of 9564
Quote:
Originally Posted by nashou66 View Post

Quote:
Originally Posted by AustinJerry View Post

I don't know, and have not heard of anyone trying this.  If you find that it works, please let us know.  Just using REW with a Mac Book presents some issues, although beta 13 is supposed to provide support.  

On Mac's there is a Audio MIDI set up application in the utilities folder.
From there you can configure speakers , then there is a selection for Multi, then a drop down menu with stereo,5.1,7.1 etc

But only stereo in available. I wonder if connecting the optical to a pre amp would open the other options.

I'll have to in investigate

Athnaasios

 

The multichannel options will only be available if the Mac detects multichannel outputs. If you only have the two internal speakers connected, the other choices will be greyed out.

 

 

post #864 of 9564
^^^ Gotcha!!

Athanasios
post #865 of 9564
Quote:
Originally Posted by kbarnes701 View Post

 

The multichannel options will only be available if the Mac detects multichannel outputs. If you only have the two internal speakers connected, the other choices will be greyed out.

 

 

 

Keith, I wonder if this is why I can only get stereo when I connect to my 4520.  When I look at the screen shots you sent me, your laptop is clearly seeing the PR-SC5509 as the output device, and the 5509 is likely reporting that it is multi-channel capable through the HDMI handshake.  On my setup, Windows Audio can only see the "RealTek HDMI Output" device, and it never detects the 4520 connected at the other end of the HDMI.  I am at a loss on how to troubleshoot this issue.  Has anyone successfully configured multi-channel output using a Denon AVR?

post #866 of 9564
Anyone have issues getting hdmi to show up in playback devices in windows 7? I have hdmi on my Sony vaio and I see it in my devices, driver is updated yet even with show disabled and disconnected both checked, I only see speakers in my playback devices. So when I connect it to the receiver I'm getting no sound. Will continue to dig and just dawned on me to try to reboot but if anyone else got through this, please let me know what you did. Thanks!
post #867 of 9564
Quote:
Originally Posted by ArthurVandelay View Post

Anyone have issues getting hdmi to show up in playback devices in windows 7? I have hdmi on my Sony vaio and I see it in my devices, driver is updated yet even with show disabled and disconnected both checked, I only see speakers in my playback devices. So when I connect it to the receiver I'm getting no sound. Will continue to dig and just dawned on me to try to reboot but if anyone else got through this, please let me know what you did. Thanks!
Which Vaio laptop do you have? On my Z series, it has dual GPUs and I have to use the Nvidia one for the HDMI port to work (slider set to "Speed"). And of course, you need to enable second display output using Function F7 if it doesn't autodetect it. If you get picture but no sound then it is none of this smile.gif.

Also, some devices only work if you disable the primary display. So use function F7 and select "projector only" and see if that makes a difference.
post #868 of 9564
Quote:
Originally Posted by ArthurVandelay View Post

Anyone have issues getting hdmi to show up in playback devices in windows 7? I have hdmi on my Sony vaio and I see it in my devices, driver is updated yet even with show disabled and disconnected both checked, I only see speakers in my playback devices. So when I connect it to the receiver I'm getting no sound. Will continue to dig and just dawned on me to try to reboot but if anyone else got through this, please let me know what you did. Thanks!

 

What is the audio chip?  I have a RealTek chip, and HDMI didn't work with the generic Windows drivers.  I downloaded an updated RealTek driver with HDMI support, and everything started working, although I only get stereo, no Multi-channel.

post #869 of 9564
Thanks guys. I have a NW series and waddya know, reboot and plug my stuff back in and hdmi output shows up in playback and mic shows up in recording. Serenity now. Thanks again! And THAT was the easy part smile.gif time to make sense of the rest of this.
post #870 of 9564
Quote:
Originally Posted by jkasanic View Post

Not Max but yes that is what he is saying with the low profile boom mic.

Quote:
Originally Posted by djbluemax1 View Post

Yep, place the stand on the floor in front of the seats. That stand will easily extend to position the mic where your ears would be in the seat.
Max

Thanks for the confirmation jkasanic. And Max, thanks for the helpful tips (pick one up for $43).
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