And do I need one?
There is a lot of jargon written in the advertising and sales listings for Android Headunits. A very common term mentioned is ‘DSP’. But what is DSP and more importantly is having one better than not having one and should I spend more to get one?
DSP stands for Digital Signal Processor.
The name explains it’s function; the audio signal is processed while still in is digital state. “But what does that actually mean?“, “what affect does it have on the sound?“, “will I be able to hear a difference?” and “is a DSP worth the extra money?” are all questions asked about the popular, but mysterious DSP in an android headunit.
The pictures linked to this post may help to explain. The hardware DSP chip can alter the features of the sound produced by the android headunit with greater control than just in software. A graphic equalizer screen allows fine tuning adjustment of the digital audio signal before it is converted to analogue, amplified and sent to the speakers to become the sound.
Can you hear the difference?
Boosting or cutting the bass, enhancing or dampening the midrange, while lifting, lowering the top end and altering the individual speaker delay times can all be achieved with great accuracy and control with a DSP and the app to control it. So, yes, you would hear the difference if you used the DSP function to change the sound.
Greater Sound Control
Typically a DSP would allow for 16 or even 32 adjustment points on a graphic equalizer whereas a software EQ would give only 8 points. A DSP chip can also make much more effective fading and balance controls with a finer level of adjustment and control of the speaker delay to really improve the fine tuning to a particular vehicle interior.
Android Headunit Tip
Not having a DSP chip inside the android headunit would mean that a limited number of these adjustments could be made in software. Off-loading the DSP duties to a dedicated circuit will relieve the processor of the work and provide a more featured DSP service to the amplifier circuits.
Sounds how you want them
Why is changing the sound so important?
It may not be important to you, and this is why a DSP may or may not be useful to you. Different vehicle shapes, quality and makes or speaker, speaker locations, interior coverings and the location of the passengers can all affect the sound. Without a DSP, you won’t be able to compensate for these variable with quite the control you can with a DSP. Not having a DSP may lead you to not quite getting the sound just how you want it, and it will be at this point, getting the android headunit with a DSP would have made more sense.
But maybe the sound tweaking to it’s nth degree is not that interesting to you? A bit of fade and bass/treble adjustment has always been adequate, but that was on the factory tuned radio you are replacing with either a universal android headunit or a custom fit android headunit, but neither has been tuned by the vehicle manufacturer for their range. Having that extra level of control may be useful?
Having a DSP means greater control over the sound, but you don’t have to adjust it from default if you are happy with the sound as it is.
Fitting a DSP
A popular question, after learning what a DSP is and finding you don’t have one, is ‘can I fit a DSP inside my android headunit’ and the answer to that is NO :(. The DSP can be seen as an option to select when purchasing, some are installed by default. Adding a DSP option increases the cost to manufacture the android headunit and you can see factory options for around $40. Don’t expect a DSP included with the very cheap android headunits because there is no value for the manufacturers to fit them and keep the cost down. But it is always worth having the DSP option, so think hard because it is unlike other android headunit add-ons that can be easily added later.
If you choose not to have DSP option, you can’t not add one inside it later.
But all is not lost if you don’t have the DSP or want something better than a factory fitted DSP. Have a look at the Axxess AX-DSP retro fit external unit. It gives you app control of the DSP features, but the DSP processing box is not inside your android headunit, but rather fitted under a seat or behind the dashboard.