Speaker Impedance measurement ,circuit and sound card output

[icbcodc]

There's a misunderstanding.

The first step is to create a first ZMA file from your existing MDAT file with the mass of 0 g,
then a second ZMA file from your existing MDAT file with the mass of 7 g,
and finally a third ZMA file from your existing MDAT file with the mass of 14 g.

The second step is to upload your 3 ZMA files into the site Speakerbench using the Collect tab. Speakerbench will create your JSON file from your data, named Zyyyymmdd_hhmmss.JSON .

The third and last step is to use this personal JSON file to get the quality fit report.
If you are unable to create the ZMA files, attach the mdat files with the 3 weights.

Hi Bernard

I just used the sample data in the speakerbench website to do the second step you mentioned, because I wanted to get to know the procedure of speakerbench and tried to find out the relatioinship between Mms and actual MASS quality by this sample data.

I know the procedure now, but I didn't do the measurement for speakerbench yesterday.

 

[icbcodc]

Why not make a big step to 50% and 25% and see what difference that makes?

Hi John

I used 3.5g and 7.0g added mass today.

I solved a few problems, first one, measure and update the value of resistor for circuit calibration.

new battery.

measured the calibration resistor,value changed. old value is 49.85ohm,current value is 50ohm.

The value of Rsense is not changed,still 98.5ohm. Because it is drifting.

So the value of Rsense is not updated.

There is another connection problem which will increase the impedance of the circuit.

If I measure the DC resistance of the speaker like the pic below, the value measured is not correct.

4.1ohm is higher than the actual value, and it's also not a steady one.

it's going up and up.

This means I can't use jig to measure the DC resistor of this speaker, even for circuit connection with this speaker.

This connection is the right way to connect with the QS-216.

New DC resistor value is drifting between 3.8ohm and 3.9ohm most frequently, so I use 3.85ohm.

Because the environment today is different.

I measure the four pieces carefully.
The high one: 1.75g

The low one: 1.75g

The left one: 1.75g

The right one: 1.75g

So m2 mass is 7.0g

m1 mass is 3.5g.

Before impedance measurement, calibrate the circuit again.

calculate T/S parameters:

7g mass simulation looks good.

3.5g simulation also looks good.

No mass simulation, perfect.

settings for exporting impedance data to zma file.

Then upload the three files to speakerbench,but failed at the second added mass ZMA file.

can not attache the last pic. :-（

 

[icbcodc]

There's a misunderstanding.

The first step is to create a first ZMA file from your existing MDAT file with the mass of 0 g,
then a second ZMA file from your existing MDAT file with the mass of 7 g,
and finally a third ZMA file from your existing MDAT file with the mass of 14 g.

The second step is to upload your 3 ZMA files into the site Speakerbench using the Collect tab. Speakerbench will create your JSON file from your data, named Zyyyymmdd_hhmmss.JSON .

The third and last step is to use this personal JSON file to get the quality fit report.
If you are unable to create the ZMA files, attach the mdat files with the 3 weights.

Upload failed, do you know why?

You can export the zma file using my mdat file.

 

[John Mulcahy]

I often get the same problem uploading to Speakerbench, I don't know the cause. Your REW measurements look good though so I'd go with the TS params you get from REW with those 3.5g/7g measurements.

 

[Bernard]

Upload failed, do you know why?

View attachment 32687

You can export the zma file using my mdat file.

Hey, guys, isn't it terrific ?

It was worth not giving up!
Upload failed this morning too and I'm obliged to send the Json file as zip file. These are the mysteries of computers. We don't always know what's going on, and the machine doesn't know either. A security problem maybe?

 

[icbcodc]

I often get the same problem uploading to Speakerbench, I don't know the cause. Your REW measurements look good though so I'd go with the TS params you get from REW with those 3.5g/7g measurements.

Hi John

I found something different between the txt file generated by REW and the sample ZMA file in speakerbench.

This is sample zma file from speakerbench,the famate is logarithmic, non linear.

the file exported from REW is linear, not logarithmic, is this the reason tha upload can not pass?

In speakerbench manual, it seems "the linear frequency measurements is also acceptable", but actually the app doesn't accept it.

 

[icbcodc]

Hey, guys, isn't it terrific ?
View attachment 32696
It was worth not giving up!
Upload failed this morning too and I'm obliged to send the Json file as zip file. These are the mysteries of computers. We don't always know what's going on, and the machine doesn't know either. A security problem maybe?

Congradulations!

The quality is EXCELLENT, how did you get the json file since the exported file from REW could not accept by the online app?

 

[John Mulcahy]

You can also export data from REW logarithmically spaced.

 

[Bernard]

Congradulations!

The quality is EXCELLENT, how did you get the json file since the exported file from REW could not accept by the online app?

You are to be congratulated for the measurements and John for the advice and the software.
For the displayed result, I simply followed the procedure indicated by the site. Sometimes it doesn't go well. This morning, for example, I couldn't validate the mass of the third file. It could be due to a server problem, erratic data transmission between sender and receiver, a ticklish antivirus, a bunch of stuff really. I'm using a VPN.

 

[icbcodc]

You are to be congratulated for the measurements and John for the advice and the software.
For the displayed result, I simply followed the procedure indicated by the site. Sometimes it doesn't go well. This morning, for example, I couldn't validate the mass of the third file. It could be due to a server problem, erratic data transmission between sender and receiver, a ticklish antivirus, a bunch of stuff really. I'm using a VPN.

Thanks.

Unfortunately, the online tool is not friendly enough to use, I also use a VPN, but I can upload the sample files successfully and can not upload the zma file exported from REW.

I have no idea.

 

[icbcodc]

You can also export data from REW logarithmically spaced.

I try to check Allow 96 PPO log spacing, and select 96 ppo when export the txt file,but the content is still linear.

 

[John Mulcahy]

I try to check Allow 96 PPO log spacing, and select 96 ppo when export the txt file,but the content is still linear.

The only selection needed is on the Export dialog, the resolution entry. Don't apply smoothing. a 96 PPO file will have about 1000 lines.

 

[icbcodc]

The only selection needed is on the Export dialog, the resolution entry. Don't apply smoothing. a 96 PPO file will have about 1000 lines.

I tried several times, the content did not change to logarithmic format.

Anything wrong ?

 

[John Mulcahy]

Those are logarithmically spaced, what makes you think they are linear?

 

[icbcodc]

Those are logarithmically spaced, what makes you think they are linear?

I thought the format of content should be like this (the sample file on speakerbench) which can be accepted by the online app.

 

[John Mulcahy]

That file is also log spaced. The numeric values are using scientific notation, but that makes no difference.

 

[icbcodc]

That file is also log spaced. The numeric values are using scientific notation, but that makes no difference.

Thank you John, I understood.

Unfortunately I cann't use speakerbench with exported data. Just bypass it.

BTW, In in latest REW, BL curve can be shown within impedance measurement (no mass) plot. It looks O.K. ？

Next step, I need to simulat the enclosure for this speaker, I can find three software: WINISD,LEAP, LspCAD, which one is recommended by you?

 

[John Mulcahy]

Yes, Bl looks OK. Want it to be level where the peak is. I don't have any experience with speaker design software so I can't make any recommendation there.

 

[Bernard]

I've tried a lot of software but since a few years, I only use the Excel Scanspeak Toolbox sheet. It's enough for me and the names at the top of the sheet give me the guarantee that the result will be correct. But you have to own Excel and activate the Analysis Toolpak add-in. In attachment, the Excel simulation with your data.
Otherwise, I like to consult the mhsoft site : http://www.mh-audio.nl/

 

[Breeman]

It depends on your intended end goal, if it is to design just a subwoofer box then WINISD should be enough. For a full scale loudspeaker project LspCad, LEAP, SoundEasy and VituixCAD should offer almost all the features you may need. VituixCAD is free also which is cool.

 

[icbcodc]

Yes, Bl looks OK. Want it to be level where the peak is. I don't have any experience with speaker design software so I can't make any recommendation there.

Thank you John.

I will try them later.

 

[icbcodc]

I've tried a lot of software but since a few years, I only use the Excel Scanspeak Toolbox sheet. It's enough for me and the names at the top of the sheet give me the guarantee that the result will be correct. But you have to own Excel and activate the Analysis Toolpak add-in. In attachment, the Excel simulation with your data.
Otherwise, I like to consult the mhsoft site : http://www.mh-audio.nl/

Thanks Bernard.

This excel file is one of the most powerful files I've ever seen.

But I need some time to understand it.

 

[icbcodc]

It depends on your intended end goal, if it is to design just a subwoofer box then WINISD should be enough. For a full scale loudspeaker project LspCad, LEAP, SoundEasy and VituixCAD should offer almost all the features you may need. VituixCAD is free also which is cool.

Thank you Breeman.

I don't need to design x-cover now, just want to make a good box for woofer/tweeter now, later I will make a box for subwoofer.

I found lspCAD is good for entire project but too complex for me, I don't need it to measure impedance anymore.

LEAP EnclosureShop looks like a powerful and complex one,but latest update time is 15 years ago, is this matter? I found its manual in Chinese language.

I also found some videos about VituixCAD on YouTube,but didn't watch them. I would like to watch them later.

If possible, I want to do more measurements for speaker such as Frequency Response, but I don't know how to do that exactly.

 

[Bernard]

Take your time. Don't forget the "readme" tab for help. Unfortunately, we can't use the Advanced button anymore because we don't have the Ams parameter. Look at https://www.avnirvana.com/threads/rew-fdd-motional-impedance-parameters.4966/post-39419
For acoustic measurements, the Umik-1 seems to be the simplest solution for a beginner.

 

[icbcodc]

Take your time. Don't forget the "readme" tab for help. Unfortunately, we can't use the Advanced button anymore because we don't have the Ams parameter. Look at https://www.avnirvana.com/threads/rew-fdd-motional-impedance-parameters.4966/post-39419
For acoustic measurements, the Umik-1 seems to be the simplest solution for a beginner.

About Mic, I already a Behringer ECM8000 for Room Acoustic Measurement,but I still need to find out the way for speaker acoustic measurement.

Equipment, Connection, Circuit, Software and procedure for measurement are basic things I need to know.