Impedance sweeps and T/S parameters

Cheap alternative to Dayton DATS and impedance sweeps. How to read the graph. Comparison of drivers.
Thanks to Frank for supplying the gear, check out HEPAKing:
hepaking.com
[e-mail]
[phone]

[@anpier926]

Thank you.

[@villageidiot8718]

Thank you for posting this informative video. I have a pair of cheap car speakers that I want to build some ported cabinets for to put in my shop. I have no clue what I'm doing but I have no specs to start from. I appreciate that you explained so much about the various parameters.

[@richardcote9663]

Wouldn't the magnet you used for added weight measuring be causing the little blips as its not centered on the driver? The weight was off to the side of the center cap. I would think that could cause a change in the response. Thanks for the videos. I continue to learn from them.

[@RAW-CAt]

Those blips are in the impedance sweeps with no mass added .

[@pabloosvaldopenizzotto1098]

This video is pure gold! Congratulations! I am doing my first steps in measuring TS parameters and to know more about how to understand the impedance curves is very helpful. Talking now about the Fs of the first drivers you have shown in the excel sheet, did you measure a brand new driver or you did it after a burn in period? From my point of view I would design my speaker cabinet after doing a burn in to my drivers. What do you think? Thanks!

[@RAW-CAt]

I did measure new drivers and I am planning to make an update video after a proper break in.

[@raynerstuelgalid]

Very clear explanation. Is there any way you can post a schematic of how the Focusrite is wired, please?

[@RAW-CAt]

Look up REW manual under "T/S parameters".

[@raynerstuelgalid]

@@RAW-CAt Thank you for the response. I have seen the REW schematic; I am just a bit blurred on the Focusrite rig itself--connected at the back of the Focusrite, is that the output jack?

[@jerryoliva6938]

Thank you for the video , great video, do you have a video with the explanation how to set up the Interface Focusrite 2i2? I have some issues to set up, thank you

[@RAW-CAt]

Maybe this will help? kzbin.info/www/bejne/e5atY2WulN9mgqs

[@sajyho1988]

Hi, thanks for all your great videos, I have a question; can this method be used for measuring impedance of an output transformer? So I can see how good is the frequency response, primary winding inductance, shunt capacitance, etc.

[@RAW-CAt]

I am not sure about that. Technically it should be possible, as it measures inductance no matter the device

[@JavierLopez-if7hb]

Hello, love your channel. what ohm value are you using in you diy DATS. 10 ohm? I am trying to build the same setup. thanks

[@RAW-CAt]

I tried a few different values and ended up with something like 40-50ohm. There is a note about resistor value in REW manual.

[@SDX9000]

great video! I wonder if using magnets next to speaker magnets is not a good idea? I guess I could cross-check the measurement with non-magnet added mass or other method, but these magnets seem to be "not by the book" when it comes to adding mass :)

[@RAW-CAt]

They are simply way to far away from the coil or the motor to have any influence.

[@macgman2000]

So I see that the V(as) = 13. xx liters. If you stick the driver into a sealed box that is 13.xx liters, what would the scan of the driver in the box look like? What measurements can I make that would indicate a proper box for the driver? What does that look like graphically or numerically?

[@RAW-CAt]

Vas has nothing to do with the "ideal" enclosure size. It's just a numerical equivalent of suspension characteristics. A "proper box" will depend on what is your goal. You can have the same woofer in three different boxes and it will perform perfectly fine. You just tailor the low end response to your needs. Whether you want more SPL or more low end extensions. The only "confirmation" that you can have if the modeling is correct is the frequency response, as that is really the only thing any software is modeling.

[@macgman2000]

@@RAW-CAt so how does the Vas factor in decision for box dimensions? I tried using WinISD but the parameters of my driver from DATS V3 breaks WinISD. The driver is a 27mm China driver and so box design data doesn't exist. I think the math breaks at this size driver because the relationships on some of the parameters depend on one being smaller or larger than the other. Most of the popular box design apps break when I put in the data. I've confirmed the correctness of my data.

[@niklaskarlsson236]

Can you please link to the connection diagram for the cables?, are you using 6,5mm stereo plugs and 1k rsense? (I have just invested in a gen4😅)

[@RAW-CAt]

You can find the wiring schematic in REW manual under impedance measurement.

[@boybalancesound]

So how do we know the value of Xmax, a measurement like this?

[@RAW-CAt]

You don't. The only way to properly measure Xmax is to get a BL curve with Klippel.

[@niklaskarlsson236]

Sorry for strange question but: 1.What sound card do you use? 2.if you "max it out" in frequency, how high can it go in RAW, a serious example can you do a calibration sweep to 50kHz, or only 20kHz? 🎉 I'm asking so I could user Rew in other use cases but I don't know what your card can do :-) Have a nice day.

[@RAW-CAt]

I am using Forcusrite Starlett 2i2 for my measurements. It is a 192kHz capable interface so I can measure all the way up to 96kHz.

[@niklaskarlsson236]

Ok, Have you done a calibration loop back test and seen that raw shows up to like 80kHz?

[@niklaskarlsson236]

Or is it a limitation in REW? (Do you have v3 or v4? Studio version or not? :-) )

[@RAW-CAt]

@@niklaskarlsson236 REW has no limitations.