I would like to test the T/S parameter with speaker workshop. I have read guides regarding this and found http://www.claudionegro.com/
However i don't have a multimeter.
May i know what i should look for when buying a multimeter for measuring the t/s parameters ? I don't wanna spend too much money on a multimeter as its not worth spending over $100 on a meter to test a $50 woofer. Thankz
However i don't have a multimeter.
May i know what i should look for when buying a multimeter for measuring the t/s parameters ? I don't wanna spend too much money on a multimeter as its not worth spending over $100 on a meter to test a $50 woofer. Thankz
pinkmouse to what accuracy must the meter measure ? I got confused by the measuring range and accuracy. In this link http://www.sanwa-meter.co.jp/overseas/product/amt/yx360trf_e.html
I see some ranges and stuff what should i look for when buying the meter for my purpose ?
I see some ranges and stuff what should i look for when buying the meter for my purpose ?
depends on Fs of your driver.
If Fs is very low then your meter may waver (or worse) trying to read voltage on very low frequency signals.
Similarly, reading the test frequency becomes difficult when trying to go below about 25Hz. FL can be significantly below Fs. FH is a bit easier to measure since it is above Fs.
None of my handheld DMMs can work with Fs~=22Hz.
If Fs is very low then your meter may waver (or worse) trying to read voltage on very low frequency signals.
Similarly, reading the test frequency becomes difficult when trying to go below about 25Hz. FL can be significantly below Fs. FH is a bit easier to measure since it is above Fs.
None of my handheld DMMs can work with Fs~=22Hz.
certainly not impossible.
But, ask the retailer how well it measures low frequency voltages. Specifically in the range 10 to 15Hz, 15Hz to 20Hz and 20Hz to 30Hz.
If it can't do that then you're wasting your money buying the instrument for Bass driver testing.
My Bench meter does it beautifully. £50 secondhand from Ebay.
But, ask the retailer how well it measures low frequency voltages. Specifically in the range 10 to 15Hz, 15Hz to 20Hz and 20Hz to 30Hz.
If it can't do that then you're wasting your money buying the instrument for Bass driver testing.
My Bench meter does it beautifully. £50 secondhand from Ebay.
I bought a mastech MS8202A a while ago for $16 american + shipping.
at 2.81V
From 10Hz -1500hz it measured
1.7% high to -1.4% low( at 10Hz)
when compared to a Fluke 867 I had access to.
I checked Ebay and I couldn't find one right now but Electronnix was his username. The numbers would fluctuate a bit below 20Hz though. You may have difficulty with your amp/source being flat well below 20hz also.
at 2.81V
From 10Hz -1500hz it measured
1.7% high to -1.4% low( at 10Hz)
when compared to a Fluke 867 I had access to.
I checked Ebay and I couldn't find one right now but Electronnix was his username. The numbers would fluctuate a bit below 20Hz though. You may have difficulty with your amp/source being flat well below 20hz also.
Several years ago I built a small opamp amp/rectifier/filter so I could reliably measure small AC voltages like you are talking about. It converted the signal into a DC voltage and amplified X10 or something.
I fiddled with speaker workshop for a while but then went to the oscillator/resistor/added-mass method to measure the parameters. I found various spreadsheets that half did the job and ended up writing my own, attached here.
One thing I found, if you want accurate Q measurements you =MUST= put the back of the speaker magnet against something solid like the end of a 100mm square post. Try it with and without to see the difference. Make sure you don't block any vent holes though.
I fiddled with speaker workshop for a while but then went to the oscillator/resistor/added-mass method to measure the parameters. I found various spreadsheets that half did the job and ended up writing my own, attached here.
One thing I found, if you want accurate Q measurements you =MUST= put the back of the speaker magnet against something solid like the end of a 100mm square post. Try it with and without to see the difference. Make sure you don't block any vent holes though.
Buzzy said:
You don't need a multimeter except to measure the calibration resistors when using Speaker Workshop.
If you want a multimeter for manual T/S measurements, you either need one with decent frequency response, or you need to compensate for the frequency response changes.
If you measure the output of your signal generator as well as the voltage across the speaker at several frequencies, you can correct for the frequency response of your meter. If the voltage at resonance (across the signal generator) is 1 volt, and the voltage a half octave below resonance (again across the generator outputs) is only 0.7 volts, you multiply the voltage measurement across the speaker by 1/0.7 at that frequency. This is a PITA and why we would rather just use speaker workshop, click an icon and get an impedance curve....
You can also measure the voltage across the signal generator, the test resistor and the speaker and from these three measurements you can get impedance _and_ phase, regardless of multimeter frequency response.
When using speaker workshop do i need to calibrate for capacitance and inductance as well if i just want to make t/s parameters measurements ? If it doesn't need then i might as well save some money on the multimeter. This is because the multimeter which can make capacitance reading costs another $20 more.
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