I've been looking for a good spectrum analysis tool that wouldn't break the bank. I found ARTA (Google it). Its demo mode is very complete and its cost is also quite low, especially considering it phenomenally rich set of capabilities.
I've been looking at oscillators and THD. ARTA can compute THD as the actual RMS value of the spectral multiples of the input signal, and also can compute RMS THD+noise, which includes everything. ARTA's precision and set-up choices are just wonderful, with support for up to 192kHz sampling and whatever the amplitude resolution of the ADC is. Of course it also has a very complete suite of generators for doing THD and IMD -- these I haven't tried yet.
I used a first-generation Griffin iMic so that I could get the ADC close to the DUT -- my computer is across the room from the test bench and I didn't want hum from long cable runs. I set a couple of breadboarded oscillators to 1kHz as read by the frequency counter in my HP 3458 DMM. Then I measured the THD only with ARTA. The readings were over 10X more than I expected. I was really unhappy with the result. Then I decided to change the frequency of one of the oscillators. ARTA immediately showed that the iMic was putting out spikes at exact 1kHz intervals -- and at 3.8kHz out, the breadboard oscillator measured around 0.005% THD, about the limit of the iMic's capability.
When I hooked up a long shielded cable to the oscillator and my on-board Intel HD Audio line-in connection, the THD dropped to 0.0018% with a 400Hz HP filter enabled in ARTA. That's good enough for my purposes for now.
I really like the aRTA suite of measurements -- I just wish it would run on the Mac side of my Hackintosh instead of the PC side.
I've been looking at oscillators and THD. ARTA can compute THD as the actual RMS value of the spectral multiples of the input signal, and also can compute RMS THD+noise, which includes everything. ARTA's precision and set-up choices are just wonderful, with support for up to 192kHz sampling and whatever the amplitude resolution of the ADC is. Of course it also has a very complete suite of generators for doing THD and IMD -- these I haven't tried yet.
I used a first-generation Griffin iMic so that I could get the ADC close to the DUT -- my computer is across the room from the test bench and I didn't want hum from long cable runs. I set a couple of breadboarded oscillators to 1kHz as read by the frequency counter in my HP 3458 DMM. Then I measured the THD only with ARTA. The readings were over 10X more than I expected. I was really unhappy with the result. Then I decided to change the frequency of one of the oscillators. ARTA immediately showed that the iMic was putting out spikes at exact 1kHz intervals -- and at 3.8kHz out, the breadboard oscillator measured around 0.005% THD, about the limit of the iMic's capability.
When I hooked up a long shielded cable to the oscillator and my on-board Intel HD Audio line-in connection, the THD dropped to 0.0018% with a 400Hz HP filter enabled in ARTA. That's good enough for my purposes for now.
I really like the aRTA suite of measurements -- I just wish it would run on the Mac side of my Hackintosh instead of the PC side.
Richiem
I am looking for a software package to use for audio measurements.
ARTA looks very good but I am not very good at getting the best from a software package if I dont have a manual I can sit and study.(1) to find out if it is the software I want and (2)operate it with full understanding as to what I'm doing
I cant find any english manuals ?
Do you know of anything?
Ianmac
I am looking for a software package to use for audio measurements.
ARTA looks very good but I am not very good at getting the best from a software package if I dont have a manual I can sit and study.(1) to find out if it is the software I want and (2)operate it with full understanding as to what I'm doing
I cant find any english manuals ?
Do you know of anything?
Ianmac
Download and set it up, there was last time I checked (prior version) a fair amount of information in the HELP.. You can't save set ups or print when in demo mode but once you purchase a license you can - otherwise its not crippled at all in that all functions/modes features used in measurements work.
Note all of the Arta manuals are here: http://www.fesb.hr/~mateljan/arta/download.htm along with the program, a personal license is 79 euros which IMHO is a good deal - it used to be a lot more.
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Two very adept engineers that I know are very happy with ARTA. I'm just about to install it on my laptop and give it a go. My friend's $30,000 HP spectrum analyzer has a noise floor of about 90 dB down. The ARTA showed noise at around 120 dB down, with the Echo Indigo full-duplex I/O pcm card attached to the laptop. Plus, you can do sinewave harmonic and I.M. distortion measurements, and if that's not enough, you can do "blackman tone burst" measurements to see ringing in the acoustics of the listening room or drivers themselves. That may be more revealing than just pink noise since ringing has a start up time and a decay time that apparently has psycho-acoustic effects on the ear-brain mechanism. Linkwitz prefers the blackman tone bursts if I remember correctly. If I can figure out how to use it, I'll be thrilled to pay the $130 or so. Best deal I'll ever get on test equipment.
So you can essentially generate your own tone bursts and capture and look at them? That would be very handy; I'm curious can you set any frequency and duration?
ARTA
If you Google ARTA, I'm confident that you'll find it. I think it's from Checkoslavakia (sp?). The manuals in english are on the website, although I vaguely remember them being hard to find in english. I haven't personally used it yet, but I've read parts of the manual, and talked with people who have been using it. I believe Linkwitz is using it now as well. I found it when I was looking for a way to measure the psycho-acoustic effects of my listening room. Where in frequency does it ring, and because ringing has both a start up time, and a decay time, how would that affect perception? I theorized that you would want to decrease amplitude of frequencies that stimulate ringing, more than a calibrated mic with pink noise would suggest. If I understood correctly, according to Linkwitz, the "blackman burst" is one of the best ways. Understanding the limitations of each test method is important. In some rooms, the blackman burst may not be as good as some other thing. If all ARTA does is turn my laptop into a great spectrum anayzer (like it did for one friend of mine), I'd call it a best buy. 120dB noise floor and excellent display. But it does so much more, if you can make sense of the manual, which didn't seem too bad last time I looked at it.
If you Google ARTA, I'm confident that you'll find it. I think it's from Checkoslavakia (sp?). The manuals in english are on the website, although I vaguely remember them being hard to find in english. I haven't personally used it yet, but I've read parts of the manual, and talked with people who have been using it. I believe Linkwitz is using it now as well. I found it when I was looking for a way to measure the psycho-acoustic effects of my listening room. Where in frequency does it ring, and because ringing has both a start up time, and a decay time, how would that affect perception? I theorized that you would want to decrease amplitude of frequencies that stimulate ringing, more than a calibrated mic with pink noise would suggest. If I understood correctly, according to Linkwitz, the "blackman burst" is one of the best ways. Understanding the limitations of each test method is important. In some rooms, the blackman burst may not be as good as some other thing. If all ARTA does is turn my laptop into a great spectrum anayzer (like it did for one friend of mine), I'd call it a best buy. 120dB noise floor and excellent display. But it does so much more, if you can make sense of the manual, which didn't seem too bad last time I looked at it.
Yes I've found ARTA extremely useful. It is incredibly easy to use, which is one of the reasons that I like it so much, especially it's logical approach to gate impulse responses.
You can use any signal for measurement and excitation within ARTA, it allows you to do this under the "external excitation" impulse response measurement. I haven't looked at the manual to figure out how to get ARTA to produce the blackman burst myself yet though, maybe this is in a more up to date version then what I'm using.
You can use any signal for measurement and excitation within ARTA, it allows you to do this under the "external excitation" impulse response measurement. I haven't looked at the manual to figure out how to get ARTA to produce the blackman burst myself yet though, maybe this is in a more up to date version then what I'm using.
ARTA and Pete Millett soundcard interface
I found the Arta software to be the best so far for audio measurements.
If you are interested in a interface in between your DUT and soundcard then have a look at http://www.diyaudio.com/forums/equi...signal-generator-fft-scope-2.html#post2449342
I found the Arta software to be the best so far for audio measurements.
If you are interested in a interface in between your DUT and soundcard then have a look at http://www.diyaudio.com/forums/equi...signal-generator-fft-scope-2.html#post2449342
Ha! 
No, not where did you find ARTA (it's Hungarian, BTW) but where did you find the Blackman Burst measurement? That's what I can't find. I'll search the manual again.
No, not where did you find ARTA (it's Hungarian, BTW) but where did you find the Blackman Burst measurement? That's what I can't find. I'll search the manual again.
Yes, hrvatski to you
Thanks Kevin for the heads up at 79euro it gets below the "just have it in the toolkit threshold".
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no need to apologize , especially to me ; it was just funny - but I thought that author of well respected software - prof. Ivo Mateljan - deserves that ppl not mix his nationality ..... when nationality is already brought to table .....
I am keen to try a speaker measurement program as I have a couple of drivers I need T&S data for.
ARTA LIMP looks a lot simpler to set up than Speaker Workshop but, having read through the manuals, I can't see any info on how to physically set up a driver for testing.
Should it be baffle mounted or suspended vertically (away from reflective surfaces etc.) ???? If the latter should it be clamped or suspend by wires/cord ???
Dave.
ARTA LIMP looks a lot simpler to set up than Speaker Workshop but, having read through the manuals, I can't see any info on how to physically set up a driver for testing.
Should it be baffle mounted or suspended vertically (away from reflective surfaces etc.) ???? If the latter should it be clamped or suspend by wires/cord ???
Dave.
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