they make devices that receive audio via Bluetooth and output either 3.5mm cable or fm modulator powered by usb "Cobra AirWave CWA BT 150" usually $39.99 this one works up to 33 feet .
I like the idea of using my Samsung Galaxy Tab Note 10.1 for navigation and music playback but I don't want to do a permanent installation. I have 3 different older BMWs I use on a rotating basis and don't want permanent installations in any of them. I am thinking that a good quality preamp with tone controls and an aux input would allow me to keep the OEM radio and integrate it with a tablet. I actually have a really nice old Precision Power preamp with very good sound quality but that has been out of production for >> 10 years for anyone else that may want to explore this route. The only currently available preamps I am familiar with are the Audio Control Three.1 or Four.1. There are other models available out there for much less money but I have no experience with any of them. I think the key thing to look for in a preamp is a DC-DC switching power supply. This will help tremendously with noise rejection and have more voltage output capability than a preamp with simple 12 VDC power directly from the car's electrical system. Both the PP unit and the Audio Control models have DC-DC internal power supplies and ~ 9 VDC output drive capability.
With the Samsung Galaxy tabs, a good quality USB DAC can be used to convert the digital data for the analog aux input on the preamp. I will try using a stalk mount for the tablet that is bolted to the passenger seat front left bolt.
The idea is that I would have stalk mounts in each car and a preamp installed in each car. I would just move the tablet from car to car and never leave it in a parked car for prying eyes to see. I already have all the pieces I need to do this install. I just have to find time to do it and post pics and a review.
check out the audison bit 1 too
I had a three.1 in my original install and the sq was great. it was being fed by an inexpensive soundblaster soundcard and was a great improvement.
as for bt, if interested (please note the limitations of bt audio) but check out the auris bt dongle. i have one at my house and the sq is fantastic for what it is. I think it would be a nice addition unless you have a fully deadened car and are competing in sq competitions
edit: the bit one may be a bit overkill for what you want. i think i'd agree with you and lean toward the audiocontrol unit
sound quality of a good preamp and DAC connected to the tablet. If ease of installation is more important than sound quality, then I think the Bluetooth device is worth considering.
I checked out your build thread. Do you still have the Behringer unit and how do you like it?
I didn't intend for you to replace the preamp only to use device as an easy connection to ur preamp
to tell you the truth i never really got the up and running and tuned before i sold the car. It was personally more work/trouble then it was worth for me, so i honestly can't give you a review of it. There is also a jvc unit...forgot what it was called. i believe it had a lot of hype when it came but can't remember the reviews. Worth checking into as another option for you
edit on my original post... i didn't have the thee.1 i had a 2xs (preamp and x-over)
what if you just used a combo USB DAC & headphone amp unit from someone like FiiO (the e10 or e17 maybe)... wouldn't that get you to speaker-level output so you could go straight into the BMW factory amps? less components means less chances for noise.
then as far as tone control, there are DSP/EQ apps for Android, but i don't know for sure if those work only with the built in DAC or not. i'm thinking they are adjusting the digital signal so they should affect a USB DAC output as well.
power output and distortion. Most low cost aftermarket amps blow it away and I actually have a collection of older used mid-to-high end amps from Zapco, Soundstream, Precision Power, and Linear Power. I have been doing mobile audio as a hobby for over 25 years and have a hard time throwing perfectly good equipment away or selling it for peanuts. I also prefer the old fashioned analog knobs on the Audio Control and PPI preamps. It is much safer to operate them without taking my eyes off the road than to fiddle with a touch screen for DSP/EQ adjustments. For music playback, I will just setup playlists so that user interaction while driving is minimal.
Using a good preamp with ~ 9 Volts RMS output capability lets me run a 'hot' signal back to the amplifier(s) and set their input gain to minimum. The formula to minimize noise is highest practical voltage at the source unit and minimum possible gain setting at the amplifier or signal processor input. FiiO headphone amps are fine products but will not compare to a good analog preamp in clarity and headroom. As long as I pay attention to system and signal grounds, I will not introduce noise by using a preamp. The primary source of alternator noise I have seen with iPods, Tablets, etc. comes from using a cigarette lighter power supply for the portable devices. Those power supplies introduce a lot of noise because they have no isolation from the vehicle chassis ground. There is a huge difference in system noise when using battery power vs. plugging into the cigarette lighter outlet. Running a portable on its own battery is always quieter than using a cheap power supply.