TS-parameter measurement setup

[graks]

Have measured 4 Seas Excel W18E001 drivers using DATS V3. Get higher Fs and lower VAS than Seas spec. Have tried with drivers on table, and now vertical, on an old front baflle. Get Fs at 43-48 Hz, and VAS at 17,7-19,5 Liter.
What would be a better setup for placing the drivers for measurement?

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[celef]

Dats v3 looks cool but i can not find any info on highest output level or output impedance, do you have these numbers?
Measured parameter values are much depended on drive level, output impedance and stimuli, if you measure with a different technic then seas then your values will differ and they can differ a lot. Brand new woofers that is not yet ”burned in” gives different values too, as temprature

 

[Lojzek]

Graks, you are wasting your time on issues that do not exist. Your TSP are whatever DATS measured and you should work with these whatever they are. Manufacturer specs are not important to you right now, they represent the driver specimen that was used back then.

 

[barackuda]

Now Im curious too, bought DATS V3 5 days ago. I will measure my driver this sunday. A modified JBL 2226H. I wonder what parameters I get.
Pictures are not showing for me...perhaps fix your link?

 

[graks]

Here are the Pictures, if it works this time..

 

[GM]

Get higher Fs and lower VAS than Seas spec.

Pretty typical and will change with break in with Fs falling/Vas increasing and don't know about nowadays, but use to the QA spec was efficiency [n0] +/- 10%, so how do these compare?

GM

 

[graks]

i should probably mount them in an old enclosure and play for 12-24 hours so they loosen up a bit. They havent been used for a couple of years.
But how is the setup for measuring? Ok to use this baffle to measure free air?

 

[Azrael]

The driver should not be installed in a baffle while measuring the TSP. It should be firmly clamped vertically, but otherwise "naked".

 

[celef]

use a wooden clamp and attach it to the driver magnet, attach the clamp to your work bench

 

[ctrlx]

try two thick battens either side of the driver instead of your baffle.
are you using a power amp to drive the dut?
after calibrating your setup, measure a 0.1% resistor, the value you get should be very close dead flat, as should be the phase at 0 deg.
after measuring t/s data, put the driver in a closed box and measure the t/s, it should match well with predicted values.

 

[ente]

… you will find some answers in the LIMP-Manual (page 14 ff)

http://www.artalabs.hr/AppNotes/LIMP_Tutorial_Version_2_4_English.pdf

Regards
Heinrich