audio tester T/S params

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emosms

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Joined 2010
#1
Hi,

I downloaded shareware of the program and trying to get any parameters.
Further on I could try to refine the measurements.

I use 8 ohm series resistor (happend to find one in the drawer) and started a sweep.

Only Sd diameter entered as parameter.

So here it is what I got: http://postimg.org/image/svbawj28p/full/

The Fs about 52/3 Hz looks realistic. The speaker is a whizzer rated 55 - 5000 hz.

What is the second spike in the graph? Is it related to the whizzer cone?

Also, I don't know how to start the second measurement (added mass for simplicity)

The program does not provide any T/S parameters for now.
Just that graph with red and blue line.
I guess the blue line is the impedance response and the largest peak shows Fs.

Regards
 
#2
Link to the shareware program would be very helpful. You must first measure Rdc, than input it in the program. Blue line is impedance, red line is phase.
Largest peak indeed is Fs, but second peak indicate something wrong in the procedure of measuring - not firmly attached driver maybe, or something touching the cone? Second peak has nothing to do with the properly glued whizzer cone. Inspect closely glued components: voice coil, cone, whizzer, spider and surround - are they firmly attached? Are leads touching the cone?
 
#5
The authors claim the software is full functioning trial for 1 month, only the working session is limited to 10 minutes, then have to restart.

Please test the software for one month and see all the measurement possibilities. In the shareware version you have all the measurement possibilities like in the full version. The real measurement time is limited to 10 minutes. After this you start the audioTester again and the next 10 minutes measurement time starts for one month.
If there are any questions or problems send a mail
Click to expand...

I sent an email to the support (on Saturday...)

It seems, I cannot switch between Measurement 1/2 (second in a sealed box or with added mass, so I guess that's why I don't get any results: View image: mes 1 2

p.s. Rdc manually added.
Thx for the speaker fastening idea 🙂. I have some angle brackets.
Anyone worked with that software?

Regards
 
#7
Because i have it use a DATS device for impedance and T/S specs, but free REW can do same via soundcard, see below from help menu.
 

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#8
Thank you, I will check that 🙂.

Latest measurements with audiotester and a question:
- because the speaker is a high Q mechanical (relatively stiff suspension) and low excursion (+-3mm) unit, do I have to use greater weight for the added mass method?

I got some more realistic Vas results, with a... Kiwi fruit of 124 grams into the whizzer cone 😀.

The resonance frequency falls DOWN to app. 25 hertz, and there is a pronounced peak: View image: m 005

If I use a smaller weight - 20,30, ... 50 gram, I am getting a hardly visible peak at around the same as Fs - the peak is just much much lower and even
 
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#9
fwiw - enough weight to drop fs a half octave (~70% of original) should be ok. Too much weight and the suspension will be out of its normal operating area. If the driver doesn't have a vented pole piece, then it could be carefully balanced on a vertically oriented piece of pvc pipe and kept away from reflections. A known volume test box can be a good way to get Vas. I often sit the magnet on the top of a piece of pvc pipe, then stabilize it with one hand so the driver won't shake or crash to the floor. That's ok with a quick sweep from WT3/Dayton DATS - two seconds and its done.
 
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#10
I got advised from xrk971 to use approx. double weight as mms spec in datasheet and it seems to work fine. Also he guided to use synthetic clay from a children toy shop that is a little sticky, find some neutral stuff that won't color cone, roll it as a rod then form a ring and press a little bit to stick around the dust cap or whizzer.
 
#11
Hi all,
I dont have ANY specs of the driver, except it is rated 55-5000 hz, ohms, 80 watts.
(clearly not 80wats, I use 40 watts to get simulation of cone movement).

It is a vented pole (some hole with a grill on the back of the magnet) and all measurements done with speaker sittin on the magnet on a piece of cloth.
Still hasn't assembled a rig, to keep it 60cm above the floor.
 
#13
emosms said:
do I have to use greater weight for the added mass method?
Click to expand...

The pioneers concluded that the ideal would be to raise the driver's Fs 1.56x in a sealed cab of known volume [Vb]; conversely, lowering it by 1.56x is the theoretical ideal when using the added mass method, though 1.5 - 1.6x is close enough, so for 52 Hz, lower it to ~32.5 - 34.67 Hz.

GM
 
#14
emosms said:
It is a vented pole (some hole with a grill on the back of the magnet) and all measurements done with speaker sittin on the magnet on a piece of cloth.
Click to expand...
Do not block the vented pole hole!!!
Just put the the driver vertically with its magnet on the edge (corner) of the table (put some small cloth beneath) and press downward the magnet with your hand, then measure it. This method is much better than blocking the vented pole while driver is horizontally sitting on the table, with or without cloth.
For proper measurements, build some jig to hold firmly the driver.
 
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