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-   -   2 Issues After Amps/Sub Installs (http://www.wranglerforum.com/f40/2-issues-after-amps-sub-installs-151144.html)

sknyfats 04-04-2012 12:05 AM

2 Issues After Amps/Sub Installs
 
I initially posted this in the JK forum but probably should've posted it here...

So I've got some killer aftermarket speakers in the soundbar & dash as well as a nice sub (2 down firing American Bass "8). I had someone do the install for me (should've done it myself, but that's another story), so I'm not 100% clear on how it's all hooked up just yet.

There's an amp powering the sub, and another amp powering the rest of the speakers - although I don't think the stock tweeters - which I haven't replaced yet - are tied into the amp.

My issue is - when I fire up UConnect, I sounds horrible now. A bit tinny and sorta distorted sounding.

Is the UConnect (the voice prompts and actual phone calls) supposed to come from the two main dash and two soundbar speakers? Are the tweeters used for that at all? Or is it just supposed to be the 2 dash or 2 tweeters? I are cornfused. And I'd like to fix it.

Anyone have any ideas what may be the problem? Everything else sounds amazing - so I'm puzzled about the prompts/phone call quality playback...

Second issue. Whenever I turn the radio on, the sub is extremely deep - too much - until I bump up the radios volume. The. It returns to a normal level. Any idea what's causing this?

Thanks - I'll do my best to get more info if any questions!

xsdbs 04-04-2012 01:09 PM

Well here you go:
1) Phone calls are limited in frequency response (bandwidth) from 300Hz to about 3.4kHz, regardless of Uconnect. The prompts, however, are split between two different bandwidths. The studio recorded prompts, which include all menu option prompts, are recorded at high quality, and played back over Uconnect with an 8kHz analog bandwidth. This is more than twice the fidelity of the telephony bandwidth, so studio recorded prompts will sound much better than phone call voices. However, 8kHz is still not truly hi-fidelity, and is a total Uconnect system design…that is, nothing is broken…it’s designed that way. As far as distortion goes, dynamic menus like phonebook listnames, and satellite station readouts use text to speech (TTS) generated prompts, which will never sound like studio prompts given the processing power of the Uconnect system. Again, this is by design, and is not a broken feature. These prompts are distorted from a speech generation standpoint, but the audio which is generated isn’t being distorted by the system.

Phone call audio is distorted by several means. The phone, and phone network generate the most distortion, specifically the GSM / CDMA / TDMA codec. The Uconnect system does not produce audible distortion on its own in this mode of operation.

How to deal with these design limitations with a higher end system? Turn down the bass….a lot! During a phone call, there is so much more information in the bass than in the upper frequency ranges. And typically, with these “bumpin” systems, the bass is substantially augmented beyond a flat frequency response which can only emphasize the design limitations. I recommend to reduce the level of bass below 250 Hz, far enough to at least match the system sensitivity at 1kHz.

2) For the added bass at lower volume, this may be an equalization level that is preset in the radio at lower volume. Kind of like the level control that some radios have for when you're driving. Ever notice that the radio volume is up while you're driving and then gets lower when you slow down? Speed compensation level controls. Another thing that you might look at is the sub amp gains and x-over point. If it's higher than about 80hz, you'll want to bring it down. The gain itself will probably need to be turned down a little also.



Quote:

Originally Posted by sknyfats (Post 2217367)
I initially posted this in the JK forum but probably should've posted it here...

So I've got some killer aftermarket speakers in the soundbar & dash as well as a nice sub (2 down firing American Bass "8). I had someone do the install for me (should've done it myself, but that's another story), so I'm not 100% clear on how it's all hooked up just yet.

There's an amp powering the sub, and another amp powering the rest of the speakers - although I don't think the stock tweeters - which I haven't replaced yet - are tied into the amp.

My issue is - when I fire up UConnect, I sounds horrible now. A bit tinny and sorta distorted sounding.

Is the UConnect (the voice prompts and actual phone calls) supposed to come from the two main dash and two soundbar speakers? Are the tweeters used for that at all? Or is it just supposed to be the 2 dash or 2 tweeters? I are cornfused. And I'd like to fix it.

Anyone have any ideas what may be the problem? Everything else sounds amazing - so I'm puzzled about the prompts/phone call quality playback...

Second issue. Whenever I turn the radio on, the sub is extremely deep - too much - until I bump up the radios volume. The. It returns to a normal level. Any idea what's causing this?

Thanks - I'll do my best to get more info if any questions!


sknyfats 04-04-2012 03:11 PM

Hmmm....gonna need to digest all that. Thanks for the detailed response though!

xsdbs 04-05-2012 09:16 AM

well, just to put it into an easier answer,
a phone call is limited in the frequency range and is not set up as "high end audio". It does not contain audio information below 300hz or above 3.4 Khz. So there is no low or upper range signals. The Uconnect voice prompts are studio recorded, so they will sound a lot better than the phone call.





Quote:

Originally Posted by sknyfats (Post 2219333)
Hmmm....gonna need to digest all that. Thanks for the detailed response though!


sknyfats 04-05-2012 03:32 PM

Thanks. I understand that, but both the prompts and actual calls sound pretty bad now. They sounded just fine on the factory speakers.

Since I didn't do the actual speaker and amp wiring, I'm thinking something isn't hooked up right and the reason that both of hear types of audio playbacks sound tinny & distorted. I'm curious of the uConnect has its own cable/connector and it just needs to be connected to a different channel or something...guess I'll just have to dig in to things.

xsdbs 04-05-2012 07:54 PM

Dont mess with the uconnect wiring, you'll really start having issues. The prompt are studio recorde but they still are not high fidelity like a cd. The uc outputs go directly into the radio which then are basically then routed thru an internal aux input. There are no external channels that it goes thru. The only other thing it can be is if any of the speakers or audio inputs to the amps are out of phase. An easy test for this is to pull the fuse for the sub amp, turn the stereo on, while the audio is playing, take the fader all the way to the front, then start moving the balance to one side. Does the audio start to sound better with the balance off center? Start to move the balance to the other side, is there any difference in audio quality with the balance off center?
Now repeat for the rear channels. Is there any difference? If the sound quality is best when the audio is in the center for both front & rear then the system is in phase.
Try the uconnect without the sub hooked up. Any difference?

Quote:

Originally Posted by sknyfats (Post 2223674)
Thanks. I understand that, but both the prompts and actual calls sound pretty bad now. They sounded just fine on the factory speakers.

Since I didn't do the actual speaker and amp wiring, I'm thinking something isn't hooked up right and the reason that both of hear types of audio playbacks sound tinny & distorted. I'm curious of the uConnect has its own cable/connector and it just needs to be connected to a different channel or something...guess I'll just have to dig in to things.



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