measuring TS parameters of metal former coil speakers

PATTOOo

Registered
Thread Starter
Joined
Oct 1, 2020
Messages
3
i am using REW for measuring TS parameters for couple of months now.
IMG_E2164.JPG
i was repairing one of my friends Marshall Kilburn Woofer. After that i tried to measure T/S parameters of it.
sorry for the bad image of 2 measurements of same woofer.
IMG_2183.JPG
whenever i measure TS parameters of metal former coil i get Zmin of 50 Ohms+ ..
is this normal ?
Qts 2.9 Woofer for ported enclosure by Marshall is it possible?
.
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
4,920
You may have the input channels the wrong way around, that gives an impedance which is offset by the sense resistor value. Try changing the input channel selection.
 

PATTOOo

Registered
Thread Starter
Joined
Oct 1, 2020
Messages
3
WhatsApp Image 2021-09-16 at 20.08.51.jpeg
i measured this few days back. and used same setup for this also.
i will try re-calibrating my test leads.
 

PATTOOo

Registered
Thread Starter
Joined
Oct 1, 2020
Messages
3
You may have the input channels the wrong way around, that gives an impedance which is offset by the sense resistor value. Try changing the input channel selection.
Thank you for the help. problem is solved.
while open leads calibrating it was going near clipping (3-4db) so i decreased level of input. and it solved the problem.
WhatsApp Image 2021-09-17 at 11.31.19 AM.jpeg
i got decent numbers now.
can you please suggest me setup for SPL measurement using U-mik ?
i should mount speaker on wooden ply like open baffle ?
 

Attachments

jschwender

Member
Joined
Mar 16, 2021
Messages
84
My AV System  
Front Speakers
Nubert digital pro
Other Speakers or Equipment
Philipd dss940
Without a baffel you don't get reasonable results. As the ideal baffle is indefinite size, this can only be approximated. So in reality your baffle will have limited size and will have an edge. At the edge there will be edge diffraction, you will see that in the frequency response. Therefore an irregular edge form, round edges with large radius or damping material helps to reduce that. If you do near field measurements, the mike distance to the speaker should be smaller than the distance to the edges.
 
Top Bottom