CLIO Pocket

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forr

forr

Member
Joined 2004
I just exchanged mails with Langston.
I encountered this problem on Windows 7 systems :
the settings size / units / smoothing / time process (impulse, step...) and windows (rectangular, auto-half Hahn) are not recalled with a measurement file.
He did'nt.
Finally, its origin seems to rely of the non-respect by me during the installing software procedure of a warning written in bold characters in the Clio Pocket manual :
Be sure to have the administrative rights when installing CLIO Pocket.
 
lholland

lholland

Member
Joined 2016
rich08 said:
Any substantial changes?
Click to expand...

Sorry to be late on this! Merry Christmas you guys. :)

CLIO Pocket v1.43 contains minor tweaks to allow Audiomatica more flexibility in hardware production that will have no effect on performance or specifications. Thus it won't hurt for current users to upgrade, but it won't help either. No feature additions are included.

The upcoming v1.50 will contain some very welcome improvements in the cumulative spectral decay plots, but is still in the pot cooking.

An interesting question is why these change logs aren't routinely included in a text file with the updates like some other companies do. Audiomatica has unfortunately experienced some pretty nasty pirating of their work and regular distribution of change logs make the bad guys' job easier.
 
G

GerardMan

Member
Joined 2017
Hello, I am new in this forum !! First of all sorry for my English. I am thinking of buying clio pocket but I have some doubts.

I can measure the impedance at various voltages to be able to use them in Leap (enclousureshop) so I could use LTD in transducer model derivation. If it can be realized that it would need some type of hardware apart from the amplifier.

Can I use the ACH-1 accelerometer in clio pocket to be able to measure resonances in the enclosures?
 
lholland

lholland

Member
Joined 2016
GerardMan said:
...I can measure the impedance at various voltages to be able to use them in Leap (enclousureshop) so I could use LTD in transducer model derivation. If it can be realized that it would need some type of hardware apart from the amplifier.

Can I use the ACH-1 accelerometer in clio pocket to be able to measure resonances in the enclosures?
Click to expand...

Hi GerardMan:

Thanks for the private message - sorry I didn't see this post earlier. :)

Good questions!

1. You can not use CLIO Pocket for high power impedance measurements because you normally need an analyzer with (2) input channels to measure both the voltage and current going to the loudspeaker driver. Impedance = Voltage divided by Current. CLIO Pocket is able to make very accurate impedance measurements up to its maximum output voltage (+12dBu) because it knows the voltage level the user has selected AND it calculates the current level by the load placed on it by the DUT.

When you add an external power amplifier in an impedance measuring setup, the measurement device then must measure both voltage and current because they both are unknowns. The one measurement platform I'm aware of that allows you to add a power amplifier to an impedance measurement setup and still use only one input is CLIO FW. In that case you use the QCBox v5 50 watt power amplifier that CLIO knows has a 26dB gain and a 0.1Ω current sense resistor. Why would CLIO FW with its two-channel input bother with a high power single-channel impedance measurement? To allow you to make simultaneous impedance and acoustic transfer function measurements. :) And to allow a laser displacement sensor on the second channel to get the most accurate Thiele/Small parameters in a single pass. Laser measurement eliminates the (minor) biases upon the DUT by an added mass or sealed air volume.

2. Yes, you certainly can measure enclosure resonances with the ACH-01 accelerometer with CLIO Pocket or CLIO FW or any analyzer that supplies phantom power between 3V - 40V.

Background

The era of scientific loudspeaker enclosure design was distilled from the prior work of people like Kellogg, Rice, Olson, Novak and especially J. E. Benson. Thiele summarized this work in tables of alignments that normal people could understand and Small, who formed a triad with Benson and Thiele, really launched scientific loudspeaker design with his papers beginning in 1972.

What all of these great predecessors had in common was that most of their math assumed purely linear behavior of the loudspeaker driver. That means very low level electrical signals were required to measure things like impedance. Many people don't appreciate the fact that even the best drivers begin to go non-linear above very low drive levels. BUT loudspeakers normally aren't used at very low drive levels and Chris Strahm's amazing work with loudspeaker design simulation incorporated higher drive levels that included non-linear physics of heating, flux fields, etc. His simulations passed the ultimate test - they matched real world measurements. Another breakthrough for normal people like us. The LTD driver modeling you referred to was the culmination of this work.

I wrote this background for the expressed purpose of honoring Chris who passed on at the end of November last year. Another huge loss to our industry.
 
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panson_hk

panson_hk

Member
Joined 2005
pansonaudio.com
I use my AP S1 (+ external amp) to perform multi-level measurement with a simple DIY VIBox (current shunt). VB script was written to do everything automatically. Output text files of the measurement are driver voltage, current and cone displacement (by a linear displacement laser sensor). These files are processed by LEAP to derive LTD models. This is not a fully automatic process but worth to get the models.

I did try the same process with CLIO Pocket. It just needed more time and switching connectors for voltage or current measurement.

Displacement data is not used by LEAP for LTD. But I can compare it to excursion predicated by LTD model.

I use the displacement data to derive TS parameters without using delta mass/compliance as CLIO FW. Calculation is done in Matlab/Octave/Scilab script.
 
S

shank1207

Member
Joined 2016
Extracting relevant information from phase data using CLIO pocket.

Hello,
I have been reading information about phase response of loudspeaker but i am still hesitant to conclude i understand it all. I would like to start with understanding the difference between the measurement of Normal, Excess and Minimum phase option in CLIO pocket and agree with what i have read, what meaningful result can i interpret from this data
 
lholland

lholland

Member
Joined 2016
panson_hk said:
...I did try the same process with CLIO Pocket. It just needed more time and switching connectors for voltage or current measurement...
Click to expand...

Ha! I didn't think of that! :)

I was focused on the fact that a single channel measurement system like CLIO Pocket couldn't do a real time impedance test using a power amplifier, thus forgot to consider simply making (2) measurements and then dividing one by the other with CLIO's math function.

One really important warning: when using external amplifiers in closed loop measurement setups with an unbalanced audio interface, you should avoid ground loops. A ground loop involving an amplifier means a great deal more current than the audio interface can handle will flow and may burn out the input circuit of the audio interface. The easiest way to "float" the ground when the amplifier has a balanced input is to connect the unbalanced audio interface output (+) to pin 2 of the amp's XLR input and (-) to pin 3. Connect nothing to pin 1, which is the ground.

Steps

1. First measure current using a 0.1Ω or similar sense resistor in series with the (-) output of the amp at the drive level of interest. Make sure you use a common ground amplifier (one that is not operating in bridged mode). Download the brochure/manual for the LinearX VIBox for circuit connection details and theory. Chris's explanation is the best I've seen.

2. Save the current sense measurement to file.

3. Now make a second measurement of the voltage at the terminals of the DUT with the software setup for impedance measurement. Make sure to use the same drive level as in #1. Then using CLIO Pocket's math function, divide the current sense measurement from #1 into the voltage only measurement currently on the display. That should show the proper impedance measurement of the DUT.

4. Save the impedance measurement to file.

Thanks!
 
lholland

lholland

Member
Joined 2016
shank1207 said:
Hello,
I have been reading information about phase response of loudspeaker but i am still hesitant to conclude i understand it all. I would like to start with understanding the difference between the measurement of Normal, Excess and Minimum phase option in CLIO pocket and agree with what i have read, what meaningful result can i interpret from this data
Click to expand...

I'm more hesitant than you are! I thought I knew a lot about this stuff until I attended a Syn-Aud-Con seminar years ago. Audio is fun because there's no end to how far you can go with it. :)

Understanding phase is a big, big deal. Keep reading and experimenting with it until it makes sense because this concept is fundamental to understanding everything we do with audio. "Minimum" and "Excess" phase are not the real phase measurement - they are fascinating and important calculations of what the phase "should be" and how far off it is from the ideal. The exact same concepts apply to group delay because group delay is simply another way to look at phase! Is this cool or what? I envy you - these concepts were some of the most exciting ones for me to learn and opened the door to huge improvements in loudspeaker design and diagnostics, arrays and pretty much everything else audio related.

Where to start? You did it by asking. Step #2 is to start reading stuff that is accurate and fairly simple. A great introduction are pages 52-59 of the REW manual:

http://www.roomeqwizard.com/REWhelp.pdf

The topic is "Minimum Phase" and I think that is probably the best term to search on in your quest to understand phase. Wait 'till you get to Heyser. He'll blow you away.
 
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E

ergo

Member
Joined 2001
Most common approach in DIY I think is the method described in this link where each of the speaker units are measured and then all in parallel are measured. Then you import the driver data to your crossover tool (VituixCAD, LspCAD etc) and add the parallel measured plot as a 'refernce plot'. Then tweak the Z axis offset of woofer until the simulated summed graph maps with measured.
Finding Relative Acoustic Offsets Empirically

Other method that I think Soundeasy process recommend also is to create Hilbert transform based phase for each unit instead of using the measured phase.
Errors which can occur in the Hilbert-Bode Transform for phase in speakers

There are many links on this topic but some more are below.
Driver Model Accuracy and its Impact on Phase
Phase, Time and Distortion in Loudspeakers
 
forr

forr

Member
Joined 2004
shank1207 said:
Hello,
I have been reading information about phase response of loudspeaker but i am still hesitant to conclude i understand it all. I would like to start with understanding the difference between the measurement of Normal, Excess and Minimum phase option in CLIO pocket and agree with what i have read, what meaningful result can i interpret from this data
Click to expand...

Have a look at Langston's video :

CLIO Pocket Time Of Flight Removal

https://www.youtube.com/watch?v=LFEwxEnpcos

it explains how to use minimum phase,
and this gives a clear idea of the concept.

Since two months, I have made hundreds of measurements using Clio Pocket.
It's certainly the easiest, fastest and most reliable tool for measuring loudspeakers available to the diyer at an affordable price.
 
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