I am new here. I just picked up a new to me 2006 Murano S AWD and immediately I was disappointed with the audio system. I am an audio design engineer and have done considerable work reverse engineering Nakamichi and Mazda car audio devices and have designed a number of products for them based on that work. So I couldn't resist the chance to crack open my head...unit and see what mysteries lie inside.
What I found...Looks almost exactly like the layout inside my Nakamichi TD-45Z car stereo! but there was also a small surprise!
Inside we find a Sanyo LC75412 Multi channel volume controller IC. this handles all the volume, fade, balance, tone, switching and loudness functions. this is the heart of the system right here!
The Nakamichi TD-35/45Z series uses a Sanyo ic much like this with the exception of an added Mid-Tone control as well. But basically these are the same chips.
And the layout of this board around this chip is STRAIGHT off the Sanyo data sheet. mistakes and all! there is much room for improvement!
one small change that can be made relates to how the tone controls work. MOST tone controls work as a "Shelf" filter. meaning that when you turn up the bass control. it turns everything from the controls center frequency(100hz) and down. up or down...THESE tone controls are "peak" controls. meaning that they work more like the controls on a graphic eq instead of a real tone control. when you turn the "bass" up, it will raise 100hz up with the width of the peak about 1 octave. but that does not raise the point where the bass (20-60hz) really is up much. same goes for cut.
On the Nak decks I was able to change the center frequency of the control and convert it to a true shelf filter which turned an otherwise useless control into a real bass control! The treble control works the exact same way! So I will dig into the datasheet and see if i can perform the same type of alterations here.
Now the real interesting thing here is that little board tacked on to the main board upside down. The second I saw that I knew what it was. so i couldn't resist unsoldering it and flipping it over. Yup! Its a vehicle specific EQ board.
What I found...Looks almost exactly like the layout inside my Nakamichi TD-45Z car stereo! but there was also a small surprise!
Inside we find a Sanyo LC75412 Multi channel volume controller IC. this handles all the volume, fade, balance, tone, switching and loudness functions. this is the heart of the system right here!
The Nakamichi TD-35/45Z series uses a Sanyo ic much like this with the exception of an added Mid-Tone control as well. But basically these are the same chips.
And the layout of this board around this chip is STRAIGHT off the Sanyo data sheet. mistakes and all! there is much room for improvement!
one small change that can be made relates to how the tone controls work. MOST tone controls work as a "Shelf" filter. meaning that when you turn up the bass control. it turns everything from the controls center frequency(100hz) and down. up or down...THESE tone controls are "peak" controls. meaning that they work more like the controls on a graphic eq instead of a real tone control. when you turn the "bass" up, it will raise 100hz up with the width of the peak about 1 octave. but that does not raise the point where the bass (20-60hz) really is up much. same goes for cut.
On the Nak decks I was able to change the center frequency of the control and convert it to a true shelf filter which turned an otherwise useless control into a real bass control! The treble control works the exact same way! So I will dig into the datasheet and see if i can perform the same type of alterations here.
Now the real interesting thing here is that little board tacked on to the main board upside down. The second I saw that I knew what it was. so i couldn't resist unsoldering it and flipping it over. Yup! Its a vehicle specific EQ board.
