Impuls response toolbox

[Jan Vandendriessche]

Dear SIr,
You have very interesting software at "octave".
I don't have big knowledge about IR, so maybe you can point me in the good direction with my small question.
Can I measure an IR from a speaker with a small accelerometer on the cone (I have already done that). I want to measure the same speaker with a microphone. I want to have to have a new IR from the difference between the microphone IR and the accelerometer IR. So I can use the accelerometer to sound like the microphone captured signal.
Is this possible with one or more of the toolbox? And what we'll be the steps?

Thank you.

Best regards,
Jan


Jan Vandendriessche

Erkend deskundige: Dr. ir. Filip J.R. Verbandt
EVA-International B.V.B.A.
Steenkaai 32
B-8000 Brugge
tel. [phone]
fax. [phone]
gsm. +32-(0)477-75.21.47
***@eva-international.com<mailto:***@eva-international.com>
www.eva-international.com<http://www.eva-international.com/>

[Sergei Steshenko]

On Thursday, November 22, 2018, 3:41:49 PM GMT+2, Jan Vandendriessche <***@eva-international.com> wrote:


Dear SIr,

You have very interesting software at “octave”.

I don’t have big knowledge about IR, so maybe you can point me in the good direction with my small question.

Can I measure an IR from a speaker with a small accelerometer on the cone (I have already done that). I want to measure the same speaker with a microphone. I want to have to have a new IR from the difference between the microphone IR and the accelerometer IR. So I can use the accelerometer to sound like the microphone captured signal.

Is this possible with one or more of the toolbox? And what we’ll be the steps?

 

Thank you.

 

Best regards,

Jan

 

 

Jan Vandendriessche

 

Erkend deskundige: Dr. ir. Filip J.R. Verbandt

EVA-International B.V.B.A.

Steenkaai 32

B-8000 Brugge

tel. [phone]

fax. [phone]

gsm. +32-(0)477-75.21.47

***@eva-international.com

www.eva-international.com

 
 
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First a dumb, but nominally correct answer to your "I want to have to have a new IR from the difference between the microphone IR and the accelerometer IR" question:
IR_difference = IR_accelerometer - IR_microphone;

where all three IRs are vectors of the same length and of the same organization, i.e. either column or row.
Now, regarding "So I can use the accelerometer to sound like the microphone captured signal" part suggests you want (rather, need) complex frequency responses and their ratio. For that start learning 'fft', 'ifft': https://octave.org/doc/v4.0.0/Signal-Processing.html .
The most difficult part which you do not address (and thus probably do not realize) is room acoustics. I.e. the accelerometer is mostly affected by the speaker cone movement while the microphone measure sound pressure produce by the speaker and by reflections from the walls, floor, ceiling and at all all objects present in the room.
You probably need to read https://en.wikipedia.org/wiki/Loudspeaker_measurement , https://www.researchgate.net/publication/2456363_Simultaneous_Measurement_of_Impulse_Response_and_Distortion_With_a_Swept-Sine_Technique .


--Sergei.

[Doug Stewart]

On Thu, Nov 22, 2018 at 8:41 AM Jan Vandendriessche <

Post by Jan Vandendriessche
Dear SIr,
You have very interesting software at “octave”.
I don’t have big knowledge about IR, so maybe you can point me in the good
direction with my small question.
Can I measure an IR from a speaker with a small accelerometer on the cone
(I have already done that). I want to measure the same speaker with a
microphone. I want to have to have a new IR from the difference between the
microphone IR and the accelerometer IR. So I can use the accelerometer to
sound like the microphone captured signal.
Is this possible with one or more of the toolbox? And what we’ll be the
steps?
Thank you.
Best regards,
Jan

Hi Jan:
I think that you would have to create a Laplace equation from each impulse
response
and the find an equation to convert the cone one into the microphone
response.
This conversion equation would then be the filter equation to make the cone
accelerometer results sound like the microphone results.
Is this what you are asking?