# REW T&S measurement



## davecandialex (Apr 27, 2011)

I have just downloaded and started using REW. I am trying to make Thiele Small measurements.
I get a pair of normal looking impedance sweeps. Free air and closed box.

I can load them into the T&S tool and enter the additional parameters, but nothing happens when I click
on calculate parameters.

One other odd thing. When I select the files from the drop down menus it only refers to them
by the date and time rather than the names I saved them with.


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## robbo266317 (Sep 22, 2008)

Welcome to HTS Dave.

Cheers,
Bill.


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## JohnM (Apr 11, 2006)

Could you attach the mdat file for your measurements please and I'll take a look at it. There are some circumstances under which the TS model fit calculations can fail, they have been fixed for the next release but I'll check the fixes work for your data.


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## davecandialex (Apr 27, 2011)

Thanks for the quick response, other parameters I put in were Re 2 to 3 ohms and
a Sd 133 cm^2


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## JohnM (Apr 11, 2006)

Thanks, those measurements are fine with the new code, if you let me know the sealed box volume I can give you the TS results. You may also find that if you start your impedance sweeps at a much lower frequency that the current code will calculate the values, enter 0 as the start frequency for REW to sweep the full low frequency range.

To change the name of a measurement type the name into the box at the top of the measurement panel, the measurement names are not determined by the file name. You can also save all the current measurements in a single file.


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## davecandialex (Apr 27, 2011)

My volume was 9.5 liter

I also made measurement with speaker workshop, which I had given up using. We can see how the results
compare.


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## JohnM (Apr 11, 2006)

Here are the REW results for those measurements.


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## Ricci (May 23, 2007)

Wait, wait, wait.... When did you add this capability John? Are you trying to obsolete every other program I use? You are getting close.


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## qingmedia (Jun 17, 2011)

REW is a great software,I love it!
I got same problem. I'm waiting for a new release that fixed the bug.


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## OldShark (Nov 7, 2010)

Hi all.
Have same problem here.


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## JohnM (Apr 11, 2006)

OldShark said:


> Have same problem here.


Are you using the V5.01 beta version which has the big fixes?


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## OldShark (Nov 7, 2010)

Hi John.

Here using the REW V5.00 build 2142. Where i download the V5.01?

I'm test in Win 7 x86 and x64 verions and audio card is U-CONTROL UCA202 with a JIG.

Thanxs for ur replay.


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## OldShark (Nov 7, 2010)

Dear John. Find here 5.1 beta 7. At night go test and after post results.
Thanxs a lot


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## HionHiFi (Feb 18, 2007)

OldShark said:


> Hi John.
> 
> Here using the REW V5.00 build 2142. Where i download the V5.01?
> 
> ...


Have you began to use the UCA-202 with Win 7 64bit? I just bought one to use with REW


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## OldShark (Nov 7, 2010)

Yeah.
Buy UCA-202, TASCAM UC-144 (old) and EMC8000 for calibration.

At nigth go test a old supwerwoofer here. A friend mine send me TS with WT3 tester of this driver. Before send 2u the measurements of using begining RES 50K and addmass 23g

[]'s


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## HionHiFi (Feb 18, 2007)

OldShark said:


> Yeah.
> Buy UCA-202, TASCAM UC-144 (old) and EMC8000 for calibration.[]'s


Thanks. I'll be using a Radio Shack analog meter for the subwoofer measurements rendering the Tascam and accompanying mic unnecessary.


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## OldShark (Nov 7, 2010)

Hello John. I'm here again LoL.

When i measured calibration, have the message:
"A timing offset of -1 samples was detected betweem the measured and reference channels, it will be compensated for, but is unusual"

I test JIG and every is ok.

Use sense res 49.9 ohms and addmass 23g

:hissyfit: Tryng send the links, but fail. 
Put the ruls in txt


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## OldShark (Nov 7, 2010)

Ohh. If like, visit our forum in Brazil.

www.htforum.com

[]'s


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## JohnM (Apr 11, 2006)

OldShark said:


> When i measured calibration, have the message:
> "A timing offset of -1 samples was detected betweem the measured and reference channels, it will be compensated for, but is unusual"


What that means is that in your soundcard, or somewhere in the path between the soundcard and JavaSound, there is a one sample delay in one channel compared to the other. If REW did not compensate for that it would affect the impedance phase measurement, so REW removes the delay. I have seen cards with a delay of a fraction of a sample between channels before, but not a full sample. The measurements will be fine however, REW is just letting you know that it has taken care of it.


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## JohnM (Apr 11, 2006)

By the way, it is better to start the measurement sweep lower than 20Hz when making TS measurements, try 10Hz or even "0". The additional low frequency information can allow a more accurate model fit.


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## OldShark (Nov 7, 2010)

Hi John. I try this, 0 to and 10 to, but the same err occur. I go to change mine JIG. In sense res go put a precision potenciometer.


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## JohnM (Apr 11, 2006)

The message about the timing offset is not an error. REW is compensating for a timing offset in the soundcard channels. The measurements are OK. You do not need to change anything.


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## OldShark (Nov 7, 2010)

Ohh ok.
Thanxs


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## qingmedia (Jun 17, 2011)

Thanks


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## OldShark (Nov 7, 2010)

Hi ging.

Here make several tests. The next step here, is calculate parameters and after compare with REW. My probleme now is the voice coil dc resistence. Every measurament the program says "DC resistence being to high". But this value is from multmeter.


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## JohnM (Apr 11, 2006)

OldShark said:


> My probleme now is the voice coil dc resistence. Every measurament the program says "DC resistence being to high". But this value is from multmeter.


Multimeters are not very accurate when measuring low resistances. Reduce the value you enter in steps of 0.5R until you do not get the message, REW will calculate the correct RE value.


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## OldShark (Nov 7, 2010)

Ok. John. Go test this
Thanxs


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## djryanash (Nov 5, 2015)

Can the calculation be done with only the "Free Air" measurement?


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