jronald

Ok, I cobbled together a system for my ZJ (Grand Cherokee). In the dash Im running the factory pair of tweeters @ 10 watts. A set 1.5 inch paper dome tweeters paired on a 50 watt amp with the front door speakers. Both the front and rear door speakers are 6.5 inch Polyprope Mid-woofers. The front doors share the tweeters in the dash, and the rear door is driven by a 50 watt amp. In the rear of the Jeep is an 8 inch DVC driven by a separate 100 watt amp. The 8 inch is also a ployprope. Everything is hooked together with low level RCA cables.

So:
10 watts to dash tweeters
50 watts to other dash tweeters and 6.5 in front door
50 watts to back door 6.5
100 watts to DVC woofer in rear

In front of the amplifiers is a 9 band EQ with an input for an MP3 player.

Im using the FM Modulator in the SkiFi2 to transfer the XM over to the head unit. The head unit does have a speaker level output issue, but since I dont use it to drive speakers, I have not given it a second thought.

Using the input on the EQ and an MP3 player, I am very, very happy with the sound. At least in my book, its a 9 out of 10. It is very live/edgy which I have historically preferred. As I normally listen to NPR on the radio, and it does not have the widest of fidelity, Im fine with the quality. Perhaps 7 or 8 out of 10. Listening to XM is painful. No distortion per se' but the sound is dull/dead/flat. I have adjusted the head unit controls, adjusted the EQ controls, tried everything I could think of....it just sounds like crap. Think of the difference between stereo and mono, what Im hearing is stereo.....but there is a HUGE difference between quality of the sound. I have tried 2 different XM radio set ups

Opinion:
Part of my speaker level output issue is in the preamp stage?
I understand the XM Modulator, automatically decreases fidelity but this much?

Whats your thoughts?

Thanks
Ron

CrazyMacaw

I'm thinking the lack of fidelity is the FM modulator and the FM receiver. Typical FM radio transmissions are highly compressed and lack depth and fidelity. How does the SkyFi unit sound compared to regular FM radio received music?

You said the EQ has an input for an MP3/line level input.
I'm guessing it's either a pair of RCA jacks or a typical 1/8" stereo jack?
You could try hooking the line out of the SkyFi2 unit to the MP3/Line input and see if that sounds significantly better just as a test.

jronald

I thought about running the SkiFi into the EQ, but I have no way to control the volume on the SkiFi or the EQ, kind of puts a damper on the idea.

FM is also dead/dull/sounds like crapola.

Ron

tornprince

not to intrude nor po anyone. why not get 1 1000watt bridageable amp and wire em up? just wonderin and i'm sorry if i po anyone.

CrazyMacaw

I think the dead/dull FM reception is a good indication of why the XM sounds bad via the modulator.

I'm going on an assumption here that you have the Delphi SkyFi2 unit.
This is not practical for daily use but maybe would suffice for just testing purposes to check the fidelity. According to the user manual for the SkyFi2 (not sure if you have one) you can adjust the audio output level but it says it's not meant to be used as a volume control.

- Adjusting the Audio Level -
The factory default setting should
work well in most situations.
However, if you hear distortion, you
should decrease the audio level. If the
XM audio level is too low compared
to other sources such as CD, cassette,
or other FM stations, you may want to
increase the audio level.
1. Press the “menu” button.
2. Use the scroll wheel (or remote) to
select “Audio Level.” Press the
“XM” button to confirm.
3. Use the scroll wheel (or remote) to
select the desired level. Press the
“XM” button to confirm selection.
4. Press the “menu” button to return
to the main menu and then again
to return to normal operation.

Note: This is not a volume control. This
feature should be used to better match the
SKYFi2 audio level with the other audio
sources in the receiver.

If the sound quality is good you could make a passive volume control out of a dual gang logarithmic potentiometer with a value between 10KΩ-50KΩ if you're electronically inclined. You could also make a passive mixer so both the SkyFi and MP3 player can operate simultaneously. The other option might be to replace the head unit with one that has an aux input

If you just happen to be using a Pioneer head unit a lot of them have an IP-Bus (aux input) connector in the back. You can get an inexpensive adapter that goes from the IP-Bus to RCA and then adapt that to what ever connector you need.

jronald

Ok got lucky and was given a DEH-P3600 Pioneer head unit. After a hack to the P-Bus on the back of the unit I was able feed the Line Level Output of the SkiFi directly into the head unit. The MP3 player still rocks, but the SkiFi sounds pretty darn good too! FM is back to normal also. Overall volume is also louder.

Started out with an un-godly ground loop issue. So far by eliminating all the grounds on the HU but the antenna, and then running "official" ground all the way back to the Amplifier grounds (locate under the console) I have it bearable.

Anyway, I guess after 20 or more years the original HU is bound for the obsolete outhouse of electronic crap!

Thanks for the help
Ron

CrazyMacaw

Glad to hear ya got it goin Rock on man!