Thiele-Small Parameters measurement using dual added mass method.

Vladimir_1953

Member
Joined
Jul 5, 2018
Messages
31
My AV System  
Preamp, Processor or Receiver
ROTEL RC-990
Main Amp
ROTEL RB-991
Universal / Blu-ray / CD Player
DENON DCD-2000AE, ROTEL RCD-991AE
Front Height Speakers
Dynaudio Crafft
What is the final ratio of the mass of the additional mass to the size of the speaker?
10 grams per 1 inch?
 

Bernard

Member
Thread Starter
Joined
May 22, 2017
Messages
59
Very good. Thanks for using Speakerbench, and thank alot to John for facilitating it.
Some measurements have been made since then. The main ones are gathered in the attached table.
I continue to measure with REW and send the ZMA curves to SpeakerBench.
The "Fit quality" tab is very handy because it allows to determine the right weight value.
However, this does not prevent you from asking questions.
Should "Error (fail > 1)" and "Zero-mass" be as low as possible?
Should "Bℓ" be as high as possible in the parameters?
Which are the main criteria ?
Fit quality table.png


5 Json files attached : 34g, 34.8g, 35g, 35,2g, and 36g.
35 g seemed the best M2 value to me, but it might be 34 g. Not easy to determine when you're not an expert.
When the weather will be less hot, I will try around 34 g, not 34°C.

27/06/2020 :
I added the corresponding mdat files. You can see an anomaly between 5 and 15 Hz. The anomaly disappears if you measure with the single mass method, M1 or M2.
The "damm" gives good results but it is more tedious than the other methods. However... You have to respect the M2 -> M1 -> M0 measurement procedure and remove the weights very carefully (which I may not always have done...).
You might want to try this new way of measuring... or not!
 

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