AudioTools 1.1
$19.99 from the iTunes app store.
Studio Six Digital
www.StudioSixDigital.com
AudioTools main screen
Let me start by saying, I really like and respect the people over at Studio Six Digital. They are good people to deal with. They are enthusiastic about what they do. Best of all, they are working hard to take acoustics measuring on the iPhone to the next level – they are the only company I know of who is producing an additional piece of hardware to allow the iPhone/iPod touch to take fairly accurate measurements in the field.
AudioTools is a suite of audio programs. Included in the suite are a:
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SPL meter
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1/3 octave RTA
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A signal generator
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Oscilloscope
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(optional) FFT analyser
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(optional) Speaker Polarity Tester
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(optional) ETC (Energy Time Curve) module
Also included in AudioTools are settings for mic and line input calibration. The mic calibration is for overall dB, there is no way to customize the frequency response characteristics of the mic input at this time.
Why a suite? Aren’t the tools available separately?
You might wonder why AudioTools was released, given that the apps are available separately. The reason lies in a hardware accessory called iAudioInterface. Apple currently limits hardware to a single application in the appstore. The iAudioInterface will be bound to AudioTools as its sole application per current apple policies. This allows Studio Six Digital to have multiple applications use the device, as each application effectively becomes a ‘plug in’ to AudioTools.
A new addition to AudioTools starting with version 1.1 is the Audio Scope. Also added is the ability to purchase the ETC module.
The Studio Six Digital SPL meter for the iPhone and iPod Touch
Oh the memories…
Studio Six Digital SPL Meter for iPhone Review
One of the first ‘tools’ I purchased years ago was a RadioShack SPL meter – it cost me roughly $50. There are a handful of uses for an SPL meter – I bought mine so I could calibrate my Dolby surround stereo – I test tone would play through each speaker – one at a time, and the SPL meter would tell me if they were all the same volume – I’d then adjust the Surround Processor until the level from each speaker was roughly the same. I’ve also used it to check volume / noise levels at various times.
This app is available separately for $1, or is included with the $20 AudioTools bundle being reviewed here.
The SPL meter from Studio Six Digital brings back memories of the old Radio Shack SPL meter – one look at both will tell you why! . The SPL meter combines the best of the old school Analog Radio Shack meter, with the newer Digital version – you get a VU meter, as well as a digital read out.
The Analog meter on the old RadioShack SPL meter didn’t have a lot of range – so you’d frequently get either no movement or it would peg to the right in a loud environment – the solution was the ‘Range’ dial – each click would change the range of the meter by 10db allowing you to get a fairly accurate reading of anything from 40 to 120 decibels. The Studio Six SPL meter for the iPhone/iPod recreates this interface on the iPod’s touch screen, with the added bonus of a digital readout that you don’t need to set the dial for – it works all the time! It also tells you what mic it’s using. Studio Six Digital has taken measurement of every iPhone model and makes adjustments to the readings based on the iPhone model’s mic and circuitry to give you as accurate a reading as possible.
The SPL meter worked just fine in my tests, behaving exactly as I’d expect. I found the touch interface on the wheel a bit cumbersome, but not enough that it would keep me from using it – (it sometimes lands on 60 when I picked 70)
One great thing about having SPL on your iPhone is that you can use it anywhere. Even discretely. So the next time you’re at a restaurant you think is just a little too loud, you’ll be able to pull out your SPL and see just how loud it is.
Studio Six Digital also sells an upgraded SPL meter for $8, The enhanced SPL meter looses the analog look, and in it’s place offers features such as the ability to store a measurement (complete with date/time, notes and the settings in use). It includes records the max volume and allows you to select a baseline volume and display the difference. (Studio Six Sells another app that is better suited for measuring volume over time called SPL graph)
The Studio Six Digital Real Time Analyzer (RTA) for the iPhone and iPod Touch
This app is available separately for $10, or is included with the $20 AudioTools bundle being reviewed here.
RTA for the iPhone is graphic display, much like what you’d see on an equalizer:
Studio Six Digital RTA for iPhone/iPod Touch
RTA’s are useful for getting a general feel for the sound you hear. The RTA shown to the left displays 10 bands, and you can change it to 30 bands for more detail. In real time as sounds come in the microphone or line in, the software breaks the sound down into either 10 or 30 different bands, then finds the peak volume within each band – the result is displayed on the bar chart. one thing to note about this is that it’s possible to have some skew – for example in the chart on the left, the 2K band is at 61 dB, but we don’t know if the whole band is at 61, or just a specific frequency – for example it could be 1.9k, 2.0k, or 2.1k – we can’t tell from that graph.
Fortunately, the 1/3 octave (30 band) graph is probably granular enough for most of us, and if not there is a $20 FFT add-in to AudioTools that shows detail down to specific frequencies.
RTA Controls and display walkthrough
Display :
The top left arrow brings you back to the AudioTools Suite, under that is the input source, to the right is the max volume across the spectrum, the right scale is the volume, bottom is frequency.
Finger swipe operations:
Using one finger left or right on the display area shows a yellow line you can scrub back and forth to identify a given frequency and see it’s current SPL. Use one finger up and down to slide the scale on the right up or down (IE instead of showing 0-100, you could show 20-120), Use two fingers to ‘pull apart’ or ’squeeze’ the display up and down to change the scale on the right. (IE instead of showing 0-100 you could show 40-80 for ‘zoomed in’ detail)
Controls:
The Octave button lets you pic between full octave (10 band) and 1/3 Octave (30 band) display.
The play pause button allows you to freeze the display.
The tilted square brings up the save dialog.
Studio Six Digital RTA for iPhone / iPod Touch Save Recall screen
The sine wave starts and stops the noise generator.
Tthe tool icon brings up the setup screen where you can set overlay curves (these super impose above the bar graph).
Studio Six Digital RTA setup screen
Of note the Show max and min bars displays little ticks above and below each line showing the highest / lowest level within a given time period.
Studio Six Digital's RTA - high low marks on each band
The final control (‘Fast’ in the screenshot above) sets the decay time of the graphs, possibilities include, fast, delays between 0.5 and 60 seconds, Peak Hold, and Average.
Studio Six Digital sells an add-in module for AudioTools called FFT. FFT does much of the same as RTA so a reasonable question is, what is different between the two?
There’s a number of improvements in FFT, and some differences, FFT uses a more accurate line graph, gives better control over some internal settings, and has a more flexible Signal generator that adds white noise, sine and square wave output. Of special note, the FFT is also a real time display, just like RTA. In general, I think RTA is great if you’re looking for an equalizer like display or want per octave (or 1/3 octave) high and low makers. FFT would be the tool of choice if you’re looking for a bit more control or need to hone in more narrowly than what a 1/3 octave graph can show you.
RTA Summary:
RTA is well done real time analyzer for the iPhone, Completely affordable either stand alone, or as part of the $20 AudioTools Suite. True audio nerds will likely want to spring for the $20 FFT module, but doing so will not make you feel cheated as there are enough differences that different occasions will warrant the use of each tool.
Studio Six Digital AudioScope for the iPhone / iPod Touch
AudioScope is a very cool addition to the AudioTools suite (new in 1.1). AudioScope is essentially an ocilloscope for the iPhone. An oscilloscope is display that charts volume over time – ‘looking’ at sounds though an oscilloscope has a number of purposes – it’s one of the best ways to ’see’ the effects of echo, distortion, etc on a sound wave. Oscilloscopes are often used for viewing continuous tones such as a sine wave. Non continuous sounds, such as snapping of fingers or a clap require the use of a triggering mechanism to freeze the display on the Scope. AudioScope features a single or multi trigger mode, which is easily set by dragging your finger from the centerline up or down -this line represents the volume level necessary to pause the scope. Like FFT, the AudioScope includes a built in Signal Generator that does Sine & Square waves, as well as white and Pink noise. Like the other tools in the suite, you can save measurements to one of 10 spots, recall a measurement, and save the images to your ‘Camera roll’ (from which you can select one or more to copy and paste into an email) Unique to AudioScope is the ability to pick the left or right input, and display L+R or L-R (the sum or difference).
Audio Scope for the iPhone showing a waveform
Audio Scope for the iPhone by Studio Six Digital with impluse response shown.
Other tools
In addition to the above included tools, there’s a utilities section that has a standalone Signal Generator with a few additional features vs the in-app generators, there’s also a place to calibrate the levels of microphones and line inputs (and outputs if you are using the iAudioInterface) The calibrations are limited to DB level only, there are no frequency response curves enterable by the end user (though this could change as the iAudoInterface has not yet been released)
Utilities page from AudioTools for the iPhone by Studio Six Digital
Signal Generator for the iPhone by Studio Six Digital
AudioTools Suite Summary:
There’s much to like about AudioTools. It’s a great affordable collection of useful acoustic measuring tools. Studio Six Digital has shown consistent development and enhancement of the product line. The ability to add other modules extends its value even more. The icing on the cake is the ability to pair it up with the iAudioInterface.