Accelerometer Testing of Loudspeaker Drivers

Hello George, I am a new member here and cannot PM you yet. However I have been using a friends AP-2 for some time and now looking to purchase or build one for myself. I am working on a very stiff and high mass aluminium rack system and have found the AP-2 / ACH-01 to be an invaluable tool. Will try to add some more posts on here and hopefully persuade the moderators that I am legitimate. Anyone can see that if you check my on Pink Fish Media - Freddiekaberman.
 
ACH-01 accelerometer seems to be out of stock now.

A good alternative choice seems to be the 805M1-0200 sensor from Measurement Specialties.
I am thinking to modify the AP-2 amplifier to accept this sensor.

I was wondering if there is enough interesting by others for this modification.
Your response is welcome.
 
From the 805M1 Datasheet: Non-Linearity (%FSO) ±1
A maybe naive conclusion: Does this mean that accuracy is 2% thoughout the whole range from 0 to 20G? If so, then this accuracy might be perfectly ok for assessing strong earthquakes, and for woofers below 100Hz (or so), where a woofer's THD might reach typical values of some 5% ... 30%? A decent speaker instead may typically have a THD well below 2% in the frequency range above 100Hz or so. So this sensor seems quite useless to me for speaker testing or for servo feedback application. Or am I wrong?
 
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If you want to attach the accelerometer to the speaker's cone another important issue you have to consider is the weight of the accelerometer sensor.

The ACH-01 has a weight of about 3 gram while the 805M1 a weight of 5 gram.
To keep the effect of the added accelerometer at a low level, the weight of the cone should be at least 10 times.
This means the speaker will be a woofer.
So the non-linearity of the sensor will not be a very serious issue.

But the main use of the accelerometer sensor with the AP-2 amplifier is the investigation of vibration issues for enclosures of loudspeakers, or turntables etc.

regards
George
 
Hi to all, I finally found the time to construct my AP-2. This was my first serious DIY project in terms of PCB assembly. I have almost zero knowledge of electronics and have only recently developed my soldering skills to a reasonable level, so this has been a learning curve to say the least.

The instructions, layout diagrams and photos provided are very clear and George has been very helpful with a couple of small troubleshooting issues. The unit is working well now and I can get on with my aluminum rack project....
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  • Thank You
Reactions: gdan
For quite some time now, the ACH-01 accelerometer has not been easy to find, although according to its manufacturer it has not been discontinued.
I thought, it is time to move on to something new.
As I have already mentioned, I chose the 805M1-200 accelerometer and I just concluded the modifications and testing on the AP-2 amplifier for this type of accelerometer. The modifications are very simple and easy to do on the existing PCB.

I have in stock some PCBs and Front Panels, as shown in post #81 for the Accelerometer amplifier.
I will also provide detailed instructions for building the amplifier and connecting the 805M1-200 sensor.
Anyone interested, please send me a message.