Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 32

 

I don't know what the Audyssey setup has to do with our discussion, Feri.  Back on topic, I presented you with a response from John M., the author of REW, saying that a microphone calibration is a required step for all mic's other than the UMIK-1, which enjoys in-built support in the current beta version of REW.  For anyone else, this would be proof enough.  Why is it not good enough for you?

 

That's entirely different isn't it? Audyssey know the input sensitivity of the mic being used, REW doesn't. With Audyssey there is no external soundcard with its own input sensitivity (which will differ from one soundcard to another). Audyssey doesn't have a gain level set in Windows to deal with (which could be set differently for any given number of users). Audyssey works in conjunction with the AVR manufacturers who reveal the specs of their AVRs to Audyssey so there are no unknown variables. Etc etc. Surely?

I have read 5 pages which means I've missed out on 27. I thought I would surprise myself by waltzing in here and downloading the easy to understand tutorial in PDF format that covers all possible scenarios. I expected a lot but what I got was not a lot. Suffice it to say, I am disappointed son. Heavens, I am disappointed ...

 

No need to be disappointed.  I provided you with a link to the guide.

Thank you very much, sir!

In that case I kindly request you to delete my name (nick) from the credits of your REW setup guide. From now on I will refrain from posting in this thread. Most probably will move out of AVSForum as a whole, indeed. No need to for me to be among a crowd that has no basics on subjects that needs to be built upon thereon.

Wish you all the best in you life.

I think this SPL meter sold on ebay would be sufficient with your guide calibrating the UMM-6 mic on step 5 regarding selecting weight C, Slow mode, 80db range.

http://www.ebay.com/itm/261152785189



Product Features :

* Easy to use and handy instrument for sound quality control in office, home, school and construction site. The meter has wide range of applications such as noise pollution studies, research and other industrial use.
* Low battery indicator
* Monitor the sound levels from traffic noise, alarm systems and workplace machinery Conformed to the IEC 651 Type 2 and ANSI S1.4 Type 2 set standard
* Wide Measuring Range: 40 ~ 130 dB
* With 2 equivalent weighted sound pressure levels A and C
* Fast and Slow dynamic characteristic modes
* Bar graph indication for Sound Level Range
* Maximum hold function
* Large LCD screen with 4 digits reading
* MAX/MIN QUASI-ANALOG BAR INDICATOR
* AUTO/MANUAL RANGING SELECTION
* Fast & Slow response selectable
* Auto power off : 20 min after non-operation

Can you confirm?

Just about any sound level meter will suffice for getting REW a reasonable calibration point.
Within a couple of dBs is going to be more than adequate for most of us.

It may be that the UMM-6 will gain full native support from REW, in which case CSL may be able to supply a sensitivity reading that bypasses the need for an external sound meter - just like the UMIK-1.
This is something that Jason and JohnM will maybe look into?

Regards, Mike.

There's a clear argument against what you've been asserting, an argument supported by the developer of the software, and when presented with this you take your ball and go home? The "S" in AVS does not stand for schoolyard.

I dont know how you missed post 891 then just a couple of pages back.

http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/870#post_22910500

I think you have got Jerry's fabulous guide now though so you are good to go.
Edited by kbarnes701 - 2/4/13 at 3:32am

 

+1. I think we can all agree now that the discussion is closed. John McMahon Mulcahy has spoken and his word is indisputable. All mics, other than the UMIK-1, need to be calibrated with a SPL meter.

 

Even Feri cannot possibly argue with the author of the software!

Edited by kbarnes701 - 2/4/13 at 6:02am

Has anyone in the UK received their UMM-6 from CSL yet? Mine made it as far as New York on the 29th of Jan, but has not moved since!
Regards, Mike.

 

Feri, if you do not mind my saying so, that is a strange position to take and perhaps, when you have had time to reflect, you will reconsider it. There is no issue of people having "no basics on subjects that need to be built upon" - you are simply wrong in your assertion that USB mics (other than the UMIk-1) do not need independent SLP calibration using an external meter. John McMahon Mulcahy has confirmed that USB mics DO indeed currently need calibrating using a SPL meter and that is now the end of it - there is no longer anything to discuss in this regard. Audyssey is irrelevant to this discussion. 

 

Your long post, with illustrations, is now seen to be misinformation (although unintended) and the honourable thing for you to do would be to correct it or delete it, in case others read it and become confused. I will delete the quoting of it in my reply to you for the same reason.

 

Personally, I hope you do not leave the thread or the whole of AVS - but it would help, I am sure, if you were able to admit when you are wrong that you are wrong instead of trying to deflect the discussion elsewhere, as in this and many other recent cases, with a view to defending the indefensible. There is no shame in being wrong sometimes - all of us are - and the majority of us are here to learn. Making mistakes is an essential part of the learning process as you know. I wish you well my friend.

Edited by kbarnes701 - 2/4/13 at 6:01am

 

Not yet. Mine was mailed out on 27 Jan. Herb used USPS which is always very slow in getting stuff to the UK - by contrast Fedex can take less than 5 days door to door. I assume you know that the UK leg of the journey is handled by Parcelforce in the UK, so you can track it on their site. But it will not appear on their tracking until they have received it of course - currently my status is showing as 'unknown' so the mic has not yet entered the UK system. I generally allow two full weeks for anything sent by USPS. I wish suppliers would give us the choice of USPS or Fedex - the latter is only a few bucks more.

 

Incidentally, the USPS tracking site will not show any more detail than you are already seeing. The mic has probably long since left New York but it won't show up as being any place else until PF get it in the UK.

I'll keep a check of the Parcel Farce site from now on, I did not know that the USPS site would stop tracking after it left the US, thanks for that.

 

Yeah - there are various sites that track USPS as well as their own, but none of them tell you what happens once the package leaves the US AFAIK. I gave a supplier a lot of hassle once when I thought the package I had waited for for days was still at the sending Post Office!  That's when I discovered the way it actually works ;)  Just keep checking the PF site.

 

This tracker site seems to believe my package is currently in Ghana, if their map is to be believed LOL.

 

http://www.packagetrackr.com/track/usps/

 

 

 

I'll post here when mine arrives of course - yours should land at more or less the same time.

I hate it when my AV equipment is better traveled than I am.

 

Hahaha!  Very good.

Guy goes to his friend's house and sees him sitting on the couch snapping his fingers. He asks him why he is doing that. He answers, "I am keeping the pink elephants away." Puzzled, the friend asks how that works. He answers, "you don't see any pink elephants, do you?"

We don't do things for the sake of doing them if we can't articulate what can go wrong. It is extra work for no reason and the longer we make this guide, the more chance it will scare people off from getting into this task. And it is not just running this once. You will have to set all the parameters to the identical values every time you start or else the calibration will be invalidated. Once you learn how to use the tool you will find yourself making a lot of measurements and anything that gets rid of tedious steps helps with getting to the data sooner will be a welcome addition.
Your commend is heard loud and clear. You want us to snap our fingers to keep the pink elephants away. Seriously, as with any other task, when you use a tool a lot as I have, you develop more optimized workflows. If you have been using REW and are an expert in it, let's have you articulate what can go wrong. If you are new to REW and/or are not able to say what "can possibly go wrong" then we don't need to waste time and energy on it in this thread or the FAQ.

 

Done. Thanks Sanjay.

Correct me if I'm wrong but this is incorrect.

I can find at least one item from ebay and amazon that doesn't seem to have the required features.

http://www.ebay.com/itm/Scosche-SPL1000F-60-to-130db-SPL-Decible-Meter-Reader-/110847703104?pt=LH_DefaultDomain_0&hash=item19cf09b840

http://www.amazon.com/Mini-Digital-Sound-Level-Meter/dp/B001THX3M0/ref=pd_sim_e_7

That is why my previous post asked someone to confirm if the meter in question will do the job. It appears that it does but I still wish for confirmation.
Edited by Stealth3si - 2/4/13 at 10:21am

What feature are you referring to that these are lacking?

All you need to do is provide REW an SPL reference point. I use my RS SPL meter for that but those with audyssey can totally work around the SPL meter requirement.

Your Audyssey mic has that reference point in the calibration file in the AVR. So after running Audyssey and all your trims are set so the test tone plays 75db. Position your USB mic at MLP(as close as possible to 1st Audyssey mic position), play your AVR's test tone which you know to be 75db, and tell REW that is 75db in the SPL meter calibration box.

There are advantages mentioned here about having REW in the right level but is it the end all be all? I say no. it's OK in my mind if comparing FR graphs and they are 3-4db off from one another. Waterfall gets weird though.

The meter you describe is fine, ok.
Regards, MIke.

Thanks for your post dstew100! This is exactly what I tried to show in my post #919 with a lot of screenshots until the "nah sayers" jumped on me (LOL). Since we have a system already level calibrated there is no need for a separate external Radio Shack (or other) meter to level calibrate REW. You can also generate a -30 dB test signal in REW to see 75 dB in REW's SPL meter panel. BTW, it can also be done with any level once the system has been calibrated by Audyssey (or MCACC or YPAO, etc.) Hope members without an external SPL meter are not discuridged any more.

Thanks for coming along.

 

I guess you mean they can't do slow/fast response and C weighting. Just get te Radio Shack version - they are abundant, cheap and work well enough.

 

I'd ignore those who say you don't need to do this step with REW. The author of the software says you do and nobody can know more then he does about REW. (If you have the UMIK-1 mic, then you are exempted).

And I said it indirectly before that :

 

I am astonished, Feri, that you feel you know better than, and disagree with, the author of the software who specifically says you do need a SPL meter to calibrate the mic (except for the UMIK-1). Constantly telling people, contrary to John M's specific advice, that they can omit this step is tantamount to disseminating misinformation. So every time you do it, I will set the record straight if that is OK with you - in the interests of balance.

So are we saying the argument comes down to "I don't need a 20 dollar sound meter, because I have a 500 dollar receiver that can accomplish the same goal in a roundabout fashion"? In either case, whether you calibrate REW to a sound meter or to an AVR receiver that's been auto-calibrated in place with a microphone of known sensitivity, have we not effectively performed the same task?

 

Your statement is not quite accurate, Feri.  When I refer to "calibrating the mic", I mean playing a test tone of a known level, and then entering that value into REW.  There are more ways than one to accomplish this.  One way is to measure the REW-generated test tone played through the AVR at a specific MV level, measure the tone with an SPL, and entering the value into the calibration input box.  I would call,this the "legacy" way to calibrate.  Another way would be to set the AVR to play a test tone at a known volume level.  As Dstew100 suggests, the speaker trim level tones generated by the AVR are 75dB, set by Audyssey.  There would be nothing wrong with using this tone of a known output level to calibrate the mic.

 

However, I stand by my original statements:  1) the microphone needs to be calibrated, and 2) the method you initially described is not a valid way to do it.