ARTA

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iMat

Member
Joined 2014
artalabs.hr
Wideband signals in ARTA

rich08 said:
Hi Ivo, would be to something cut off frequency in sweep generator?
for example, i am thinking maybe when measuring tweeter, fr or distortion...
Click to expand...

ARTA measures frequency response with wideband signals that garantee high S/N on all frequencies.
In acoustical environments almost always there are higher noise at low frequencies and we prefer using pink noise or log swept sine signals.
Sometimes, i.e. when measuring tweeters, we want less energy at low frequencies - to protect tweeter - then white signals: mls, noise or linear swept sine can be used.
In both cases excitation signals must be wideband one.
If you want to measure in restricted fr. range use program STEPS.

Ivo
 
I

iMat

Member
Joined 2014
artalabs.hr
rich08 said:
Ivo, which model of Limp is best in practical use, L2R, L3R or L2RK. It appears that the best results are obtained L2RK, but in your paper you write that L2R and L3R model is preferable in standard circuit analysis software.
Thank you.
Click to expand...

It depends on which simulation software you use, or maybe you do simulations by programming circuit equations. I do not use ready made simulation software. I rather write simulation programs in Matlab language. In that case L2RK model can be incorporated in circuit analysis, as model of choice. For standard circuit simulation software, that use only frequency independent L,C,R elements you may use L3R model.
Do not forget to check if you can use measured impedance data. It is the best option.
Ivo
 
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rich08

Member
Joined 2012
iMat said:
It depends on which simulation software you use, or maybe you do simulations by programming circuit equations. I do not use ready made simulation software. I rather write simulation programs in Matlab language. In that case L2RK model can be incorporated in circuit analysis, as model of choice. For standard circuit simulation software, that use only frequency independent L,C,R elements you may use L3R model.
Do not forget to check if you can use measured impedance data. It is the best option.
Ivo
Click to expand...
Thank Ivo for answer
I use only classic LSPCad 5.25, I dont work with circuit equations.
 
I

iMat

Member
Joined 2014
artalabs.hr
rich08 said:
Ivo, thank you for update...
I wanted to ask, is the point detection of a higher harmonic distortion, F6 and more?
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It was may observation that Farina method for distortion estimation is reliable for 2nd, 3rd and 4-th harmonics for most sound cards and in all acoustical environments. I can let ARTA estimate 5th or 6th harmonics but it requires higher quality sound cards for electronic measurements and low noise acoustical measurement.

Best,
Ivo
 
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rich08

Member
Joined 2012
iMat said:
It was may observation that Farina method for distortion estimation is reliable for 2nd, 3rd and 4-th harmonics for most sound cards and in all acoustical environments. I can let ARTA estimate 5th or 6th harmonics but it requires higher quality sound cards for electronic measurements and low noise acoustical measurement.

Best,
Ivo
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I understand, I think that's how it should be with the quality of cards very well, until you can feel some integrated, but the environment is obviously difficult ...
Question, icon to distortion in the Arta?
Thank you
 
dave123

dave123

Member
Joined 2004
hey guys.
I'm looking for someone who has ARTA with a license (commercial version). actually I'm testing a custom plugin on my website that can display live graphs so everyone could track the frequency response or whatever measurement interactively. a commercial version of ARTA is able to export > CSV which could be used here.
thanks,
 
D

dumptruck

Member
Joined 2010
dave123 said:
hey guys.
I'm looking for someone who has ARTA with a license (commercial version). actually I'm testing a custom plugin on my website that can display live graphs so everyone could track the frequency response or whatever measurement interactively. a commercial version of ARTA is able to export > CSV which could be used here.
thanks,
Click to expand...
The free version exports CSV too. Do you just want random CSV files or what? I have a bunch, but you could also just go to the parts express website and download the ones they have on the product pages for most of the newer Dayton drivers (all of the "designer" driver series, for example).
 
C

Chris3P

Member
Joined 2015
Which usb soundcard?

I wonder if anyone has experience of using a Maplin HD 7.1 USB Sound Card with ARTA? It seems to fit the bill (24bit/192khz/108dbSNR/ASIO driver) and is available fairly inexpensively (£50). It appears to use a CMedia CM8828 DAC chip. I'm looking around for a suitable usb soundcard and this looks like it might be ok. I'd be using it with windows 7. Thanks in advance for any advice.
 
I

iMat

Member
Joined 2014
artalabs.hr
Swept sine is not good for impedance measurements?

rich08 said:
Ivo, question, what do you think of measurements impedance with sweep signal. I believe that it has some advantages, of course, in terms of resolution, the stepped sine is of course better. It also has some major drawback?
Thank you for answer
Click to expand...

It is not only my opinion that swept sine is not good excitation signal for loudspeaker impedance measurement. The explanation lies in bad rejection of impulsive noise, which is very often present (as loudspeaker acts as microphone). The effect of impulsive noise appears in measured impedance data similar as resonance behavior of driver.

Best,
Ivo
 
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rich08

Member
Joined 2012
Thank you for answer...
Last time I tried to compare, stepped sine, pink PN and sweep. The best results I achieved with stepped sine, very similar sweep, sweep was obviously faster, but the worst periodic PN, which was expected. Only when more powerful and several times the repetition and the results were averaged asynchronous periodic PN similar to the stepped sine. Increasing volume resulted in distortion and deformation
 
I

iMat

Member
Joined 2014
artalabs.hr
rich08 said:
Thank you for answer...
Last time I tried to compare, stepped sine, pink PN and sweep. The best results I achieved with stepped sine, very similar sweep, sweep was obviously faster, but the worst periodic PN, which was expected. Only when more powerful and several times the repetition and the results were averaged asynchronous periodic PN similar to the stepped sine. Increasing volume resulted in distortion and deformation
Click to expand...

Hi,
Keep in mind that all three signals are good for specific measurement environment.

- Swept sine is best signal for fast indoor measurement with low impulsive noise present. Generally, averaging should be avoided.
- PN Pink noise is excellent signal for rejecting impulsive noise but averaging is necessary to reach dynamic range of swept sine excitation. For example, I have got better reverberation time measurement with pink noise in airport check-in halls.
- Stepped sine gives us an order of magnitude better measurement S/N, but it is not applicable to impulse response measurements. It is also best for loudspeaker impedance measurement.

As you see, all three signals are necessary.

Best,
Ivo
 
R

rich08

Member
Joined 2012
iMat said:
Hi,
Keep in mind that all three signals are good for specific measurement environment.

- Swept sine is best signal for fast indoor measurement with low impulsive noise present. Generally, averaging should be avoided.
- PN Pink noise is excellent signal for rejecting impulsive noise but averaging is necessary to reach dynamic range of swept sine excitation. For example, I have got better reverberation time measurement with pink noise in airport check-in halls.
- Stepped sine gives us an order of magnitude better measurement S/N, but it is not applicable to impulse response measurements. It is also best for loudspeaker impedance measurement.

As you see, all three signals are necessary.
Best,
Ivo
Click to expand...

Thank you Ivo... I compared the signals to measure impedance under normal conditions, there I went aforementioned results...
Ivo has one question, the best signal to measure in standard, rather small, little fill room.
 
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