JAY X

True RTA and VA analyzer software
« on: October 15, 2016, 07:28:49 AM »
Hi!

Anyone using these programs?.  I have the Visual analyzer : http://www.sillanumsoft.org/download.htm

despite it is free, it is quite difficult to use... And the true RTA... i have the free version, but it is not clear that i can test any audio device with this version.

Maybe someone here has experience with True RTA or visual analyzer...

Any comment is wellcome!

JAY X


arnyk

Re: True RTA and VA analyzer software
« Reply #1 on: October 15, 2016, 09:01:58 AM »
Anyone using these programs?.  I have the Visual analyzer : http://www.sillanumsoft.org/download.htm

I've experimented with VA and had some success with it.

Quote
despite it is free, it is quite difficult to use...

I've noticed that it can be hard to use. Lots of options, and not all of the defaults are the best.


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And the true RTA... i have the free version, but it is not clear that i can test any audio device with this version.

You can often break audio analysis programs down into two groups - those for speakers and rooms, and those for electronic gear.  They are often quite different from each other and somewhat specialized. 

RTA programs are more for checking out and setting up rooms. Other good freebies  in that category are Holme Impulse and  REW - Room Eq Wizard.

For an easy but fairly comprehensive program for testing audio gear, check out RMAA - the Rightmark audio analyzer.

In the gear testing category, also check out Arta which is more like shareware, though the freebie version is no slouch.


JAY X

Re: True RTA and VA analyzer software
« Reply #2 on: October 15, 2016, 12:29:27 PM »
Hi Arnyk!

With VA analizer, the difficult part is to have a flow to make the measurements. There are some  articles about calibration procedure that i could follow. But there is not a test device proceeding. ¿do you have one that works?

jay x


arnyk

Re: True RTA and VA analyzer software
« Reply #3 on: October 16, 2016, 09:18:02 AM »
Hi Arnyk!

With VA analizer, the difficult part is to have a flow to make the measurements. There are some  articles about calibration procedure that i could follow. But there is not a test device proceeding. ¿do you have one that works?

No.  I tend to shy away from software-specific calibration procedures.  I generally use an external, audio -band true RMS meter (like the Uni-T UT 61)  to directly measure the output of the UUT. 

Products like the UT-61  tend to be more optimal for use in the US and other countries with 120 VAC-based power, and with SS gear. 

If you are in  a place where normal line voltage is more like 220-240  volts, or you are working with tubed gear,  higher quality gear that handles higher voltages more  comfortably  like most Fluke meters is  safer.

Andy Peters

Re: True RTA and VA analyzer software
« Reply #4 on: October 16, 2016, 06:19:57 PM »
RTA programs are more for checking out and setting up rooms.

You do not want a simple RTA program for measuring systems in rooms. You need a two-channel transfer-function analyzer, which gives you phase response. Without the phase response, you won't know what could be the cause of bumps or suck-outs in the amplitude response.
"On the Internet, nobody can hear you mix a band"

JAY X

Re: True RTA and VA analyzer software
« Reply #5 on: October 17, 2016, 04:20:46 AM »
Hi!

I think finally will get the True RTA software. It is quite good measuring noise from audio devices, and it is easy to use. The only doubt about this kind of programs is if i REALLY need white noise generator to perform an audio test of any piece of harware, or PINK noise is more useful. Besides, True RTA has a sweeping mode to measure the frequency response of the DUT.

Besides i will get an AMPROBE AM 530 RMS multimeter to measure AC millivolts.

jay x
« Last Edit: October 17, 2016, 04:24:32 AM by JAY X »

ruffrecords

Re: True RTA and VA analyzer software
« Reply #6 on: October 17, 2016, 06:12:13 AM »
Hi!

I think finally will get the True RTA software. It is quite good measuring noise from audio devices, and it is easy to use. The only doubt about this kind of programs is if i REALLY need white noise generator to perform an audio test of any piece of harware, or PINK noise is more useful. Besides, True RTA has a sweeping mode to measure the frequency response of the DUT.

jay x

Depends what you want to measure. If you want to measure frequency response then you can use either white noise or a sweep.

Cheers

ian

sahib

Re: True RTA and VA analyzer software
« Reply #7 on: October 17, 2016, 07:18:03 AM »

Besides i will get an AMPROBE AM 530 RMS multimeter to measure AC millivolts.

jay x


Bear in mind that it has a frequency range of 45Hz to 400Hz.  I would look for even a second hand but proper analogue audio/ac milivoltmeter if you are tight in budget.

Sometimes ago I launched a test jig kit which esentially allows unbalanced test equipment to be used  in balanced environment. It can be quite handy for generic testing of auido gear.

http://groupdiy.com/index.php?topic=60805.msg772290#msg772290

arnyk

Re: True RTA and VA analyzer software
« Reply #8 on: October 17, 2016, 10:34:09 AM »
You do not want a simple RTA program for measuring systems in rooms.

Of course not!

How many times in  even the past few weeks have I recommended  two-channel analysis programs like  Holme Impulse and  Room Eq Wizard?  Why don't you agree with those posts of mine such as  http://groupdiy.com/index.php?action=post;quote=811120;topic=64072.0#postmodify instead of being disagreable?

Quote
You need a two-channel transfer-function analyzer, which gives you phase response.

Measuring phase response in a room makes little sense since the response in a room above its Schroeder Frequency (above 100 Hz or so) is by definition a random field where phase and amplitude are random and only make sense when summed statistically.

The genesis of room measurement techniques  has shifted from using white or pink noise in the 60s and 70s to the current practice of using  swept tones in the interest of obtaining accurate measurements of statistical frequency response as quickly as possible.

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Without the phase response, you won't know what could be the cause of bumps or suck-outs in the amplitude response.

Humps and dips in rooms are generally due to standing waves that  correlate with distances between the alrger and more reflective surfaces in the room.  Usually, the best solution is to use absorbers (either broadband or narrow band) to damp them. Peaks can also be tamed with equalization.

The usual work flow is to identify the frequencies where the standing waves are the strongest with the software previously mentioned, and then survey the architecture of the room for the larger more highly reflective surfaces  whose dimensions and spacing match up with the dips and peaks that have been measured.   Then appropriate sound absobers are fabricated or otherwise obtained, and mounted for the most effective results.

For example a large meeting room had very uneven bass response. Some of the audience complained about how thin and lacking in energy the sound was, while others complained about heavy bass and thick boomy sound. It was found that there was a regular pattern of dips and peaks whose most noticeable  effects were in a broad region around 50 Hz.

Large sound absorbers  based on high density fiberglass about a half a foot deep were applied to the wall that seemed to be generating the strongest reflecations and therefore were causing standing waves. They largely elminated the problem. At no time was anything but loudness considered. The frequency related information obtained with measurements almost perfectly matched distance measurements based on just listenting and measuring with a tape measure.

arnyk

Re: True RTA and VA analyzer software
« Reply #9 on: October 17, 2016, 10:48:38 AM »
Depends what you want to measure. If you want to measure frequency response then you can use either white noise or a sweep.

White noise was largely discarded for doing frequency response testing decades ago because its energy is unnaturally weighted towards the upper frequencies. In the 60s and 70s it was replaced with pink noise which is more strongly weighted towards the lower frequencies by means of electrical filtering.

Most PC-based audio test and measurement software can generate many different kinds of noise including white, pink, and red or brown. In addition some of the better software allows the statistical density of the test wave to be adjusted.  MLS is a kind of a noise-like signal that has been optimized for better performance than what can be obtained with pink noise.

As more reliable and precise measurements became more desired in the 80s and 90s, improvements in analytical software shifted the test signals types  towards swept tones and multitones.

If you try to measure with 0.1 dB accuracy it quickly becomes clear that it takes measurements based on random noise test signals must be averaged and it takes a long time for the averages to  stabilize.  In contrast , much more accurate frequency response measurements can be performed more quickly using swept tones and multitones.

Today swept tones are probably the most widely used, but for many applications faster and more accurate results can be obtained with multiones.


arnyk

Re: True RTA and VA analyzer software
« Reply #10 on: October 17, 2016, 11:10:55 AM »

Bear in mind that it has a frequency range of 45Hz to 400Hz.  I would look for even a second hand but proper analogue audio/ac milivoltmeter if you are tight in budget.


This is a point that IME needs to be made very clear - when you are doing audio testing it is very helpful to have a meter that has accurate response over the usual audio band - 20 Hz to 20 KHz. or an even wider range if possible.

Low cost DVMs  often have response that rolls off sharply above 1 KHz which can make it very difficult or impossible to use for audio purposes.

DVMs with audio features such as dB calibrations and wide enough frequency response have become quite rare.

Without a reliable test, I wouldn't know what to make of some of the equipment I see being offered. For example, a meter that has a spec such as  "±(1.0 % Rdg + 3 LSD) @ 45 Hz to 400 Hz, 4 V to 400 V ranges"  could be more useful than it would first seem.

While it is specified over 45 Hz to 400 Hz, it could respond well over a wider range and just be under-specified.  Or not. The 1% tolerance given approximately corresponds to 0.1 dB which is good enough for a lot of typical audio work if present over the 20-20 Khz range. 

Depending on the intended use of a voltmeter, frequency response over a wider range could be counter-productive. If I was measuring an AC power line for general use in a kitchen or machine shop, high frequency noise measurements may be largely meaningless or even counter-productive.

Here is a site that does some very detailed evaluations of a variet of modern DVMs: http://www.eevblog.com/forum/index.php

Andy Peters

Re: True RTA and VA analyzer software
« Reply #11 on: October 17, 2016, 07:33:21 PM »
Of course not!

How many times in  even the past few weeks have I recommended  two-channel analysis programs like  Holme Impulse and  Room Eq Wizard?  Why don't you agree with those posts of mine such as  http://groupdiy.com/index.php?action=post;quote=811120;topic=64072.0#postmodify instead of being disagreable?

I'm just pointing out that you said, "RTA programs are more for checking out and setting up rooms. Other good freebies  in that category are Holme Impulse and  REW - Room Eq Wizard."

The implication here is two-fold. One: RTA programs are useful for checking out and setting up rooms, which is false. Two, you mention those two programs in the same line as "RTA programs ..." and the reader might assume that those programs are indeed RTA programs.
"On the Internet, nobody can hear you mix a band"

arnyk

Re: True RTA and VA analyzer software
« Reply #12 on: October 18, 2016, 02:59:29 AM »
I'm just pointing out that you said, "RTA programs are more for checking out and setting up rooms. Other good freebies  in that category are Holme Impulse and  REW - Room Eq Wizard."

The implication here is two-fold. One: RTA programs are useful for checking out and setting up rooms, which is false. Two, you mention those two programs in the same line as "RTA programs ..." and the reader might assume that those programs are indeed RTA programs.

Well Andy,  your implications are your implications (much more so than mine) and your statements of fact, and also yours. I don't appreciate having false claims stuffed into my mouth.

Lets look at your alleged facts.  Are RTA programs utterly and totally useless for checking out and setting up rooms? Can you find even one independent authority other than yourself to back that up? 

I can find dozens of recent articles on the web describing how to use pink noise and a RTA for loudspeaker and room setup. This is not proof that it is the best way, but it is evidence that people are still doing it and getting what they find to be useful results.

I think my words are pretty clear - pink noise RTA tests are outdated technology and have been superseded by newer technology, but they can still be used for checking out and setting up rooms if you are willing to accept their limitations. Lots of people still are,

Even the TrueRTA site says: https://trueaudio.com/rta_abt1.htm  "Measure the frequency response of a loudspeaker system using either pink noise or Quick Sweep."

They are clearly recommending the use of a RTA and pink noise for setting up rooms and loudspeakers (since you can't separate the sound of a loudspeaker from the effects of the room it is in).

Secondly, the implication that Holme Impulse and REW are the same is another one of your misunderstandings Andy, not anything I want to stand behind.   What I meant is that they serve the same basic purpose - acoustical measurements.  And, I find your misinterpretation of what I said to be demeaning and insulting.  It ignores the fact that my recommendations on this site have always been of REW and Holme Impulse.  Until now I've avoided RTA/Pink noise measurements.

For example, have I ever even mentioned on this site using any specific programs for RTA/pink noise testing. Note that I just  quoted the TrueRTA site only because it says what it says, not as any kind of personal  advocacy of their product.

For everybody who might be confused,  while Holme Impulse and REW  can be used for setting up rooms and speakers, they are not RTA/pink noise programs and use more recent and effective technology.  RTA programs and pink noise testing have been legacy technology for setting up rooms and speakers, and still work to some degree.

 But, since you can get good freeware that uses the more recent better technology, why pay for old technology?

« Last Edit: October 18, 2016, 03:16:54 AM by arnyk »

gyraf

Re: True RTA and VA analyzer software
« Reply #13 on: October 18, 2016, 07:10:16 AM »
Arnyk,

You're being unnecessarily harsh. Calm down or take it easier at least. If you have commercial or emotional interests invested, just let us know and we'll be more respectful about specific products.

Jakob E.
(mod-mode)
..note to self: don't let Harman run your company..

JohnRoberts

Re: True RTA and VA analyzer software
« Reply #14 on: October 18, 2016, 10:45:30 AM »
+1  we mods have enough to deal with responding to reported spammers.

The is no rule against being authoritative but try to tone down being so personally argumentative. You are using up your nine lives (that number is arbitrary but this is not your first warning). 

There are other people around here with experience and strong opinions.

I feel bad even saying this but we have a pretty civil group around here, and would like to keep it that way. 

JR

John Roberts
http://circularscience.com
Tune it, or don't play it...

abbey road d enfer

Re: True RTA and VA analyzer software
« Reply #15 on: October 19, 2016, 07:09:19 AM »
RTA programs are useful for checking out and setting up rooms, which is false.
Please elaborate; I believe something is missing.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
"The important thing is not to convince, but to give pause for thought." (B. Werber)
Star ground is for electricians.

Andy Peters

Re: True RTA and VA analyzer software
« Reply #16 on: October 19, 2016, 07:33:00 PM »
Please elaborate; I believe something is missing.

The quoting system used by the forum has changed, so now when you click "quote,"  only the post to which you are replying is quoted. Previously-quoted replies are not included. So I will try to reconstruct this ...

RTA programs are more for checking out and setting up rooms. Other good freebies  in that category are Holme Impulse and  REW - Room Eq Wizard.

and I replied to that:

You do not want a simple RTA program for measuring systems in rooms. You need a two-channel transfer-function analyzer, which gives you phase response. Without the phase response, you won't know what could be the cause of bumps or suck-outs in the amplitude response.

To which Arny replied:

Of course not!

How many times in  even the past few weeks have I recommended  two-channel analysis programs like  Holme Impulse and  Room Eq Wizard?  Why don't you agree with those posts of mine such as  http://groupdiy.com/index.php?action=post;quote=811120;topic=64072.0#postmodify instead of being disagreable?

To which I replied:

I'm just pointing out that you said, "RTA programs are more for checking out and setting up rooms. Other good freebies  in that category are Holme Impulse and  REW - Room Eq Wizard."

The implication here is two-fold. One: RTA programs are useful for checking out and setting up rooms, which is false. Two, you mention those two programs in the same line as "RTA programs ..." and the reader might assume that those programs are indeed RTA programs.


Now, if the question is, "Support your assertion that RTA programs are not useful for checking out and setting up rooms," I already mentioned why. Single-channel RTA programs don't give you phase information, unlike a two-channel transfer function measurement system. And that's the reason why the guys who set up large performance spaces and studios use transfer-function systems like SIM and Smaart.

"On the Internet, nobody can hear you mix a band"

Andy Peters

Re: True RTA and VA analyzer software
« Reply #17 on: October 19, 2016, 07:35:02 PM »
Measuring phase response in a room makes little sense since the response in a room above its Schroeder Frequency (above 100 Hz or so) is by definition a random field where phase and amplitude are random and only make sense when summed statistically.

Then why do the guys like Sam Berkow use dual-channel transfer-function measurement systems, which absolutely give phase information, when setting up studios and performance spaces?

-a
"On the Internet, nobody can hear you mix a band"

Andy Peters

Re: True RTA and VA analyzer software
« Reply #18 on: October 19, 2016, 07:42:55 PM »
Well Andy,  your implications are your implications (much more so than mine) and your statements of fact, and also yours. I don't appreciate having false claims stuffed into my mouth.

You are the master of stuffing false claims ...

Quote
Lets look at your alleged facts.  Are RTA programs utterly and totally useless for checking out and setting up rooms? Can you find even one independent authority other than yourself to back that up? 


I mentioned Sam Berkow in another post. Do you know who he is?

Quote
I can find dozens of recent articles on the web describing how to use pink noise and a RTA for loudspeaker and room setup. This is not proof that it is the best way, but it is evidence that people are still doing it and getting what they find to be useful results.

Sure, you can find articles supporting pretty much anything. Does RTA provide useful information? Yes, if the user understands what he's getting. Too often, the user will see a ragged frequency-response curve on an RTA display and will futz with an equalizer to make the display flat. And does it sound good? No. Why not? Because EQing for one particular location in the room means that you ignore all other locations.

Quote
Secondly, the implication that Holme Impulse and REW are the same is another one of your misunderstandings Andy, not anything I want to stand behind.

See, now you're making things up. I never implied that those programs are the same. I never even implied that I know anything about them. All I said was that, "The implication here is two-fold. One: RTA programs are useful for checking out and setting up rooms, which is false. Two, you mention those two programs in the same line as 'RTA programs ...' and the reader might assume that those programs are indeed RTA programs." That is exactly why I assumed those programs were "RTA programs."


Quote
What I meant is that they serve the same basic purpose - acoustical measurements.  And, I find your misinterpretation of what I said to be demeaning and insulting.  It ignores the fact that my recommendations on this site have always been of REW and Holme Impulse.  Until now I've avoided RTA/Pink noise measurements.

See above. You say one thing in one post, then when your words are repeated back to you, you claim your statements were misrepresented. And if you take that as an insult, then you should seriously consider how you write.

Quote
For everybody who might be confused,  while Holme Impulse and REW  can be used for setting up rooms and speakers, they are not RTA/pink noise programs and use more recent and effective technology.  RTA programs and pink noise testing have been legacy technology for setting up rooms and speakers, and still work to some degree.

This clarification was added after the fact.

-a
"On the Internet, nobody can hear you mix a band"

JohnRoberts

Re: True RTA and VA analyzer software
« Reply #19 on: October 19, 2016, 08:55:23 PM »


I mentioned Sam Berkow in another post. Do you know who he is?

-a
Can anybody answer? 

Sam is the "smart" guy..... 8)

JR

PS: We need Dave with his anvil of truth, but most people here won't get it.
John Roberts
http://circularscience.com
Tune it, or don't play it...