With digital signal processors getting powerful and available widely, there is a whole of stuff becoming possible in the consumer electronics area. Large guitar amps that are all digital are able to produce effects similar to the classic analog amplifiers. The harmonics and clicks of the tube amps can be replicated quite well on digital signal processors. So far there have been large amplifiers available from manufacturers like Fractal Audio which have bulky, professional grade products like Axe-Fx that can create all sorts of audio effects. When it comes to smaller form factor, Apple products have been at the forefront of audio fx products because of their class-complaint USB audio interface drivers on iOS. Unlike Apple, Android devices do not have native support for class-complaint USB audio devices causing a great problem for making real-time audio products.
Android’s audio problem
Due to Android being open source, manufacturers like Samsung have their own Professional Audio SDK that uses its own audio drivers to achieve what Google didn’t. Android also has an inherent inability to record real-time audio and output the same on the speakers. There is a huge delay between audio entering the device and exiting towards speakers. Add in an additional delay of processing and applying guitar effects. The result is just not satisfactory.
Samsung’s Professional Audio SDK worked only on Samsung devices and IK Multimedia’s iRig HD-A took advantage of it and provided a low latency guitar effects emulator. Not everyone has a Samsung device and Android has a huge ecosystem. If IK Multimedia wanted to capture customers, they had to expand their product for other devices as well. Another big problem with Android being that the upgrade from one version to the next version of Android is quite slow. Therefore, a lot of users will be stuck on 2 to 3 year old OS. So they had to take care of that too.
IK Multimedia’s iRig UA is a nice little low latency device that works on Android 4.2+ devices and comes in a tiny little form factor. It operates on the power supplied by the USB port and hence, you need a device that has USB host/OTG capabilities.
Hardware Architecture of iRig UA
Why do you need a iRig UA when you can simply plug in your guitar in to your phone’s audio jack? Firstly, the problem of severe delay and secondly the audio input circuitry of a phone is not meant to handle high quality audio coming from your guitar. You will find that the music you just recorded has been severely degraded in terms of audio quality. Products like the iRig UA come with the additional circuitry required for conditioning the audio signal. A general audio processor will have an input buffer or a pre-amplifier, a high resolution analog to digital converter (usually in the range of 16 to 32 bits), an up sampler which could be replaced by a faster sampling ADC, a DSP for processing the signal mathematically, then a down sampler to to bring the audio sample rate to a standard value and finally a digital to analog converter and a power amplifier that feeds the signal to speakers. Much of this is already present inside any modern phone, except the pre-amplifier and a high resolution ADC/DAC. Since, phones are not really professional audio devices, manufacturers choose to put a low resolution ADC/DAC.
iRig UA build
iRig UA has an input jack for guitar and an output jack that pushes out processed audio. Apart from that, there is the USB interface that feeds the iRig UA’s DSP with the mathematical equations required for modelling and applying the desired effects to guitar audio. IK Multimedia also provides an Android application called AmpliTube which does the task of communicating with the iRig UA about which we will talk later in the article.
iRig UA also has a volume control dial and besides it there is a auxiliary input jack in case you wish to feed audio from your iPod or your phone.
iRig UA internals
iRig UA comes with a 24 bit ADC which has a sampling rate of 44.1kHz or 48kHz, which can be selected through the app. There is a low noise pre-amplifier section to buffer the input audio signal before passing it on to the DSP. IK Multimedia does not specify the components and chips used in the product, however they did specify using a 32 bit signal processor, which is pretty common for such applications. We can assume it to be a Texas Instruments TMS320 DSP which is quite inexpensive and operates at a clock speed of up to 300MHz. They could also be using some solution from NXP or other Cirrus Logic. It is still unclear.
Some might question, why not use the powerful applications processor present on our smartphones? We have to consider the reality that Android runs on a huge ecosystem and not all devices will have a ub3r powerful processor. In order to provide consistent low latency audio across all devices, it is a good idea to offload the signal processing to dedicated hardware. The result is 2ms round trip delay. A huge improvement over Android’s audio system.
The app interfaces with the hardware and makes sure to configure it with necessary mathematical coefficients to achieve desired model and effects response. It is a simple to use application. At the top you have to pick up the amplifier model, then there is the option to choose effects such as clean, crunch and lead. You also get the option to vary the gain, bass and treble just like you would do on a real, bulky amp. Just to make a note, not all amps are bulky and you should check out Blackstar HT-1 for its super compact form factor.
The modelling library is expandable and currently has a total of 21 different guitar gears. There are 9 high quality stomp boxes, 5 amps. AmpliTube even provides model for 5 cabinets that go with the modelled amps and even 2 microphones. With such vivid, ever expanding collection of guitar gear you can implement a variety of combinations to achieve the sounds you like. It is as if you have an entire guitar playing setup at your finger tips for a fraction of the cost.
IK Multimedia also allows you to buy additional models from brands such as Fender, Orange, Ampeg, Soldano and more.
After looking at the tremendous possibilities, we need to see if it can actually produce the mentioned sound effects.
According to user’s experiences, there is absolutely no feeling of delay. You hear the sound as you play. Clean channel sounds pretty quiet, just the way it should. There did not seem to be any kind of frequency response manipulation done here. Although, when you switch on to gain channels you begin to miss the bulky, classic amps. The reason being that iRig UA is not as responsive as you would expect it to be. While the real tube amps will display that thumpy punchiness when, iRig UA fails at it. Thumps sound like they have been slightly muffled and spread.
Putting on the Marshal model and turning the gain knob up does result in rough sounds. With this combination you can also experience the sustain quite well. But if you have a real Marshall sitting besides you, the difference will be instantly noticeable. iRig UA works quite well but it still isn’t up to the level where ‘real deal’ stands. A lot of users were mentioned that no matter what model they tried and what settings they adjusted the thing to, one cannot achieve the performance of a real tube amp. That does not mean iRig UA is useless junk, but simply means that it cannot be used for professional performances.
iRig is a great device for beginners and get used to various knobs and settings. If you cannot afford to buy an expensive amp and a cabinet, iRig UA is for you. Once you cross a certain level and become ready to setup on to the next level, you should consider buying a professional grade guitar amp and experience the real deal.
There is no other device like iRig for Android and thus IK Multimedia has no competitor. Things might change once Android 5 gets more popular in the coming days. We can very well expect the audio on Android to improve and the delay to disappear. Once that happens, professional audio gear will come along to Android side.
Works on any smartphone or tablet that supports Android 4.2 or higher and host mode/USB OTG
Near-zero latency digital FX processing
Digital audio recording on Android 5.0 and Samsung Professional Audio Devices