cheahcl

Hello guys, hoping someone can lay some insights my way because it isn't making sense to me.

I've had the 9886 installed for over a year but never got around to troubleshooting. On my previous car, a volvo 850, I too replaced the stock HU with an Eclipse CD5000 with the same effect.

In both cases, the cars had factory amps and the proper harness was used to convert Headunit RCA out -> harness -> factory amp wires. Both cases the bass became tiny after, even with the bass on the aftermarket HU maxed out. With the stock factory system, both cars had adequate bass for my liking. Actually when the concert stereo was maxed out, the bass was a lil too loud for me even. Now, it's like the depth of the bass is lost more so than how loud it is..

Thanks!

VP Electricity

Can't speak to the 850... but if you have a non-Bose system in many Audi (I don't know the year of the car involved), the Audi HU boosts the bass a lot at lower volumes, before the amp. At higher volumes it should sound fine, though.

If you have a Bose system, I'm not sure. Try racking the balance all the way to one side and see if the bass gets better. If you, you have one side out of phase with the other side. Easy to test.

VP Electricity

I guess you did say Mk I, sorry. Bose?

cheahcl

Yes, Bose. The phasing is a good idea. I'll go try now, though I doubt that is the case. If the concert HU boosts the bass alot, how do I replicate that?

cheahcl

oops can't edit my previous msg. I've tried the balance and it isn't a phasing issue. Let's just say the bass doesn't go as low anymore. Like every frequency has a +20hz to it or something. Maybe the bose amp doesn't like the signal the alpine HU is sending. Must be some way to correct that?

VP Electricity

The concert and symphony HUs change their output depending on whether they are connected to a Bose amp or not. When connected to a Bose amp, the output is hardly different from an aftermarket HU.

As far as the Bose amp not "liking" the bass... I've avoided changing HUs on Bose amps, because I hate Bose amps and Bose speakers - but I've heard that some Audi systems carry a good bit of DC offset in the audio output and that the Bose amps have a lot of input filter capacitors to take the DC out. Bass "looks like" DC. But I haven't experienced this and have no idea how to get around it if it is the problem.

Audi systems used to use a common ground, where most other OEs use a balanced system that rejects EMI noise a lot better, so the DC offset thing was an attempt to make the signal to noise ratio a lot better.

I assume the crossover in the Alpine is turned OFF...?

cheahcl

The 9886 doesn't have a crossover unless it has been imprinted. Mine hasn't.

I used this to connect pre-amp rca out to the bose line ins.

http://www.bipesauto.com/SLK/DLD/index.htm

This guy is claiming a differential line driver is better than the regular passive connectors. Do you think this will make a difference? Or maybe I should get the PAC OEM-2?

By the way, I just recalled I got a ground loop isolator in between the headunit rca out and the rca in on the bose harness because the speakers were popping when I changed stations on the tuner.

marcus.sharks

Based on MY personal experience (and taste) and many other SQ forum members in Brazil, there is nothing wrong with what you get from the 9886. It´s actually doing its job quite well, as you described it.

My ears are trained for SQ (high fidelity) and as I was testing each and every car me and my wife were planning on buying, I found ALL cars to be boomy, in terms of bass, except for the Volvos with Dynaudio set.

Alpine has a "tradition" in Brazil to be known as more focused on reproducing the sound as it was recorded, not so much in adapting it to the likings of bass lovers (even if you boost it to max).

Fact is: most ppl like more bass than what the recorded version has - nothing wrong with that.

If you REALLY like boomy (or thicker, for that matter) bass, see if you can try a Pioneer HU. Pioneers are known for being preety booomy.

Also, I´m pretty sure you have MEDIA XPANDER on your 9886. Try turning it on and tell me the results - ppl call the Media Xpander as "Pioneer function" in Brazil, LOL!