Accurate Tuner Pro is a chromatic instrument tuner, which combines two classical pitch tuning methods: Needle and stroboscope.

The needle enables fast and comfortable rough tuning, while two optional stroboscopic animations facilitate fine tuning. Both methods are used at the same time, so it’s not necessary to choose one of them. Detected notes are shown on a musical staff. Adjustable sensitivity will help in not so quiet environments.

Free Trial Version

• Fully working needle and strobe tuner with no time limit, supported by ads
• Strobe accuracy: +/- 0.5 cent
• Needle accuracy: 5th octave: +/- 0.2 cent, 6th octave: +/- 1 cent, 0th octave: +/- 6 cents
• Range: A0 – B6
  The tuner is able to measure tones in the 0th and 1st octaves for some harmonically very rich instruments only, as common phone microphones are not able to detect these low frequencies. Still the tuner tries to compute these tones from higher harmonics, sometimes successfully. Even a human ear works this way.

• 126 instruments + “Any instrument” mode
• Transposition: +/- 4 octaves, two transposition modes
• Adjustable sensitivity
• US (CDEFGAB), German (CDEFGAH), scientific (C2, C3, C4) and Helmholtz (C, c, c’) notations

126 instruments

Full Version

• Tone Generator able to play notes from A0 to C8 (88-key piano range) or any frequency from 27.5 Hz to 4186.01 Hz. You need solid external speakers or headphones for the two lowest octaves.

Tone Generator

You can set the frequency directly and also set the levels of harmonics and form the wave shape this way (not the wave envelope).

• Screen Lock Blocking

Small part of settings

• Adjustable base frequency (note A4) in the range of 300 – 500 Hz
• 32 temperaments

Accurate Tuner Pro supports 32 temperaments.

• Many alternate instrument tunings, including 70 guitar, 25 banjo and 19 mandolin tunings

Accurate Tuner Pro supports many alternate instrument tunings, including 70 guitar tunings.

• Unlimited number of custom instruments and tunings
• No ads (on rare occasions it may recommend another app in a non-intrusive way)
• Bigger stroboscopic part

Future Plans

• Metro design

Marketplace on the Web

Tamara Volskaia domra, Iskrina Matveeva piano: Tchaikovsky Danse russe:

The two videos below illustrate the situation. First the trouble (Mango is installed on the phone, while the emulator still uses NoDo and works properly):

Then the solution:

I promised to explain it in detail back then, but I lacked the time to do it. Now, when I have sent Accurate Tuner Pro to the Marketplace certification, I can fulfill my promise and write a short series about this issue.

Perhaps it is not so important now, because new Tango update is behind the corner and may fix it. In the last part of this series (3rd or 4th) I will publish the source code for the Carousel object, which is used by Accurate Tuner for harvesting solid sound data from somewhat broken Mango microphone.

To map the problem I have created a simple tone generator. It produces a 500 Hz wave (B4 + 21 cents) with a specific shape: “Normal” wave has the amplitude of  5.000, while every 10th wave has the amplitude of 15.000. The resulting “hedge clipper” shape makes a growling sound and looks like this:

Source Debug Wave 500 Hz with 50 Hz markers

Click on it for a bigger picture.

Wave parameters:

• Sampling rate: 16 000 Hz – the default sampling rate of Windows Phone OS 7.0 and 7.1
• Base frequency: 500 Hz, wave length 32 samples
• Frequency of the markers: 50 Hz, wave length 320 samples

Tone Generator source code:

/// <summary>
/// Creates the DEBUG Wave with the debug parameters
/// </summary>
public void CreateDebugWave()
{
    // DEBUG PARAMETERS
    _samplingRate = 16000;
    _frequency = 500;
    double _normalAmplitude = _amplitude = 5000;
    double markerWaveAmplitude = 15000;
    int markerWaveStep = 10;

    int waveLength = (int)(_samplingRate / _frequency);
    int markerSampleStep = markerWaveStep * waveLength;

    double doubleSample = 0;
    Int16 intSample = 0;
    byte[] byteSample = new byte[2];
    double b = (Math.PI * 2) * _frequency / _samplingRate;

    int j = 0;

    // The wave buffer is one second long
    //
    // This works for whole number of waves (= integer 
    // frequencies) only. 500 Hz or 440 Hz is OK, while
    // 261.63 Hz will make a snapping sound every second.
    //
    for (int i = 0; i < _samplingRate; i++)
    {
        // Marker wave creation
        //
        // This is simple and clear, but not very efficient.
        // It doesn't matter here.
        //
        if (i % markerSampleStep == 0)
            _amplitude = markerWaveAmplitude;
        else
            if (i % markerSampleStep == waveLength)
                _amplitude = _normalAmplitude;

        doubleSample = Math.Sin(i * b) * _amplitude;
        intSample = (Int16)Math.Round(doubleSample);
        byteSample = BitConverter.GetBytes(intSample);

        _buffer[j] = byteSample[0];
        _buffer[j + 1] = byteSample[1];

        // DEBUG For debug visualization purposes only
        _bufferInt16[i] = intSample;

        j += 2;
    }
}

/// <summary> 
/// Creates and plays the wave.
/// </summary> 
public void Start()
{
     // DEBUG 
    CreateDebugWave();

    SoundEffect sound = new SoundEffect(_buffer,
                        _samplingRate, AudioChannels.Mono);

    if (_isPlaying)
    {
        _soundInstance.Stop();
        _soundInstance.Dispose();
        _soundInstance = null;
    }

    _soundInstance = sound.CreateInstance();
    _soundInstance.IsLooped = true;
    _soundInstance.Volume = _volume;

    _isPlaying = true;
    _soundInstance.Play();
}

/// <summary>
/// Stops playing the wave.
/// </summary>
public void Stop()
{
    if (!_isPlaying)
        return;

    _soundInstance.Stop();
    _isPlaying = false;
}

By the way, the more universal version of this tone generator is included in Accurate Tuner Pro.

Now the interesting part begins: To avoid any mistake in my code I’ve used the standard Silverlight Microphone Sample provided by Microsoft. It uses 500 ms long sound buffer by default. This is the record it produces on NoDo (recorded in the 7.0 Emulator of the 7.1 SDK):

Debug Wave recorded by NoDo 7.0 Emulator in SDK 7.1

I’ve carefully reviewed much longer part of the record and found no irregularities. This data is solid and can be safely used by Accurate Tuner for two purposes:

• Wave vizualization, which is phase-normalized for the stroboscopic efect usable for fine tuning.
• Fast Fourier Transformation algorithm, which analyses component frequencies for rough tuning.

Next, let’s run it on Mango:

Debug Wave recorded by Mango 7.1 Samsung Omnia 7 with 500 ms buffer

The growing amplitude is probably caused by the automatically adjusting microphone sensitivity of the phone and is not interesting for us now, it reaches some maximum amplitude and then stays constant. Another thing is more important – I haven’t found anything wrong with this signal too.

Is this the way Accurate Tuner records sound? Almost. 500 ms sound buffer is good enough for most recording purposes, but it is too long for tuners or sound visualizations, because you need fast response in these cases. The shortest buffer length allowed by WP 7.0 and 7.1 is 100 ms and Accurate Tuner uses this buffer length.

So let’s change the buffer length to 100 ms. The picture is wider now, so click on it to maximize it:

Debug Wave recorded by Mango 7.1 Samsung Omnia 7 with 100 ms buffer

Folks, this is clearly wrong!

Apparently, some sound data is lost!

This explains everything: While common sound visualizations used for estetic purposes only will still look as usual, a stroboscopic animation will be inevitably completely broken. FFT will provide more interesting and confusing results, as there are still big portions of correct waves here, but these portions are phase-shifted. The final results will be unstable and very inaccurate, but not completely wrong.

Which is exactly the behavior of the original Accurate Tuner Beta algorithms.

(I’m skipping the chart of the NoDo 100 ms buffer, but believe me the record is perfect and looks just exactly as the chart with the 500 ms buffer. I would also point out that the described issue is present in the WP 7.1 Emulator too, so it isn’t specific for Samsung phones.)

What to do with it??? FFT will work correctly, if only “safe part” of the buffer is used, for example 50 ms. But it will be extremely inaccurate. In fact, even 100 ms is not enough and several buffers must be joined for the analysis to be meaningful. Or I can change the buffer size to 500 ms, but the FTT results would be very delayed in such case and almost unusable. And the wave visualization delayed by 0.5 s will be just comical.

We will see next time.

To be continued.

Can you tell 10 differences?

As you can see, on the surface almost nothing has changed. So sorry folks, still no Metro design. (But don’t worry too much as I plan a major design overhaul for the next major update.) This update was about improving the internals. And they have been much improved!

Another source for concern may be the apparently missing ad banner. Is the Pro version paid? Yes, it is. But don’t panic, there is a free ad-supported trial with no time limit.

Free trial version has all the features of the Beta with just one exception – it doesn’t support adjustable base frequency and has A4 fixed at 440 Hz. On the other hand, it has some additional features and even this free trial benefits from the improved algorithm with better accuracy, stability of results, sensitivity and range! The paid version has many new features.

Robert de Visée: Suite en la mineur, Prélude et Allemande, Jonas Nordberg, theorbo:

The new BIOS killed the battery.

MyNokiaBlog was able to join these micro-spots into one, cca 10 second long video, without sound:

The official launch of Nokia 800 and at least one more Window Phone is expected this Wednesday at Nokia World in London.

The countdown has begun!

Yes, it was more demanding than I expected, but all’s well that ends well. After some final testing I will publish the update, so it will be available in the marketplace in a few days. Also, I will publish my findings about the changed Microphone object behaviour in Mango on this blog.

Let’s comment on the video:

• Notice the Middle C on the Yamaha keyboard is marked as C3, while the tuner shows C4. It is correct – it really is C4 in the scientific notation, used by the Accurate Tuner (261.64 Hz).
• My left thumb is shaking… no, I’m not that old or terrified, just a little cold.
• The fundamental frequency detection is not perfect. Different tone letters or octaves are flashing at times – this is typical for this hard-to-tune guitar with nylon strings I used for this video. Fortunatelly, it’s better with other instruments, including steel-string guitars. In fact, all these tones are harmonics of the base frequency, so do not really matter. All harmonics are in tune at the same time, so you can safely ignore letters and concentrate just on the needle and/or the wave.
• When you get accustomed to it (and use steel strings ), you can tune your instrument extremely fast using the wave only.
• Accurate Tuner design is not Metro and not even beautiful, I know. But it works! Don’t take it for granted, smartphone tuners in general rather do not work well. ;-)

Top: NoDo OS version (WP 7.0 – emulator from SDK 7.0, spring 2011 update)

Bottom: Mango (WP 7.1/7.5 RTM, Samsung Omnia 7)

Select 720p.

When in tune, the Wave above the Needle must stand still.

This beta has better than 0.1 Hz accuracy on NoDo, but doesn’t work at all on Mango. Microsoft has changed the Microphone XNA object behavior. The FFT part (Needle) of the Tuner is less accurate and unstable now, results are completely wrong for lower frequencies. The strobo part doesn’t work at all. And the sound wave has very different shape, it seems to be flipped on both axes…

The app had average rating of 4.88 in the Marketplace before Mango. It will go down fast now, of course. It will take at last a week before the update will be published. I should have test it on Mango before the Mango public release, I know. But I honestly hadn’t expected this kind of change… I’m trying to figure these changes in the XNA sound processing and to fix it ASAP, but it doesn’t seem to be trivial at first. Does anybody know what has exactly changed with Microphone, XNA events dispatching in Silverlight etc. in Mango?

http://accuratetuner.com

**********

Status update

I hope I’ve already localized the issue – and yes, there is a real change of the Microphone behavior, although it probably still is in accordance with the documentation.

Včera začal Microsoft distribuovat dlouho očekávanou zásadní aktualizaci Windows Phone – verzi 7.1/7.5 s kódovým jménem Mango. Update je však rozloženo do několika týdnů a jen asi 10% uživatelů bylo nabídnuto hned první den. Naštěstí existuje jednoduchý způsob, jak váš telefon k update přinutit.

Návod

1. Protože je součástí update zálohování obsahu paměti telefonu, které může trvat desítky minut, doporučuji před aktualizací odstranit z mobilu hudbu a odinstalovat nepoužívané aplikace.
2. Připojte telefon k počítači. Spustí se program Zune.
3. Vyberte Telefon -> Nastavení -> Aktualizace. Pokud je zde k dispozici update, už na vás došla řada a prostě je potvrďte. Pokud vám Zune stále tvrdí, že je váš telefon aktuální, pokračujte dalším bodem.
4. Zvolte z levého menu Zune jinou volbu, např. Bezdrátová synchronizace. V této chvíli musí být váš počítač připojen k internetu. Připravte se na jeho rychlé odpojení, například vytažením ethernetového kabelu nebo vypnutím WiFi hardwarovým tlačítkem.
5. Klikněte opět na položku Aktualizace a asi sekundu poté odpojte počítač od internetu. Pokud budete mít štěstí, Zune vám nabídne aktualizaci.
6. Počítač opět připojte k internetu a aktualizujte.
7. Při neúspěchu bodu 5 opakujte body 4 až 5 stále dokola. Chce to trpělivost, mně se to podařilo až asi na dvacátý pokus, jiným napoprvé.
8. Protože se před Mangem (build 7720) musí nainstalovat aktualizace 7392 a 7403, je možné, že budete muset celý proces několikrát opakovat, jak se to stalo některým lidem v zahraničí. Já jsem už měl nainstalován build 7392, nabídlo se mi update na 7403 a po něm se automaticky nainstalovalo Mango RTM 7720.

A užívejte si Mango, které je opravdu chutné! Všechno ve vašem telefonu bude najednou fungovat lépe a první dlouhý stisk tlačítka Zpět (multitasking) je opravdu zážitek.

Jediné zklamání, které mi update připravilo, bylo uzamčení mého zcela legálně, avšak nestandardně, odemčeného telefonu. Nové odemčení je pro mne poněkud komplikovanější, neboť ještě nejsem registrován jako český vývojář. Ale to jsem stejně v nejbližších dnech plánoval udělat.

Naopak velmi příjemným překvapením je česká klávesnice. Domníval jsem se, že bude k dispozici jen na nových telefonech, ale update ji přineslo i na ten můj.

Fotoreportáž

Váš build 7392 je aktuální, Mango pro vás nemáme!

Jsem připojen k síti. Vyberu v menu aktualizaci a...

...rychle odpojit od sítě! Myslím, že jsem uspěl, když jsem to udělal asi po půl sekundě.

No vida, Mango leželo pod pultem. Tedy přesně řečeno je to přípravná aktualizace 7403. V této chvíli nezapomeňte znovu zapnout internet, já osel jsem to poprvé neudělal a vše bylo třeba opakovat.

Aktualizujeme...

Po nainstalování 7403 se automaticky začala instalovat aktualizace 7720, tedy vlastní Mango. Záloha telefonu znovu neproběhla.

Hotovo.

Mango je Windows Phone 7.1, Microsoft je nicméně marketuje jako 7.5. Nenechte se tím zmást.

Tublatanka, Dnes:

There should be some pictures and an ordering form on their website fusiongarage.com, but I wasn’t able to find it yet. There were no mentions of a promised SDK and very little about native 3rd party software. They will open Grid Shop – their own app marketplace – soon, and Grid OS is able to run side-loaded Android software.

Grid 10 Tablet

Tegra 2 dual-core, 10″ LCD, 1366 x 768 pixels, 1,3 Mpx front facing camera, 16 GB, microSD slot, Bluetooth, WiFi, 3G optional

• without 3G: 499 USD
• with 3G: 599 USD

Grid 4 Phone

Qualcomm dual-core, LCD 800 x 480, rear-facing  camera 5 Mpx with autofocus, front-facing camera 0,3 MPx, 16 GB

• unlocked: 399 USD

So I was right it is not Nokia and/or Microsoft.

(Just kidding.)

Green Day, Boulevard Of Broken Dreams: