A note about ARTA audio analysis software

[richiem]

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.

[head_unit]

Very interesting. Have you messed with it enough to tell me if it can do long-term spectrum averaging? (Like 1 hour+)

[richiem]

It lets you set the number of samples averaged, but I don't know the upper limit on the number. You can try it for free as often as you want. I think the free version's only limit is that you can't save set-ups. It is a very good analyzer. I haven't tried the other functions.

[Ianmac]

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

[kevinkr]

Originally Posted by Ianmac

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

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.

[Ianmac]

Thanks Kevin,
will take your advice and go for it

Ianmac

[Bob Richards]

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.

[head_unit]

Originally Posted by Humdinger

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?

[Pano]

Originally Posted by Humdinger

.. 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's interesting. Not seen that before, where did you find it?

[Joachim Gerhard]

Praxis can do that since a long time. I know that because i was instructive to implement it.