View Full Version : Keep the stock Headunit? STS 310 07-09-04, 05:43 PM Alrite fellas,
I have a Delco HU in my STS. I have come to the conclusion that it is not Bose based on the fact that it sounds close to crap, and i see no identifying markings. I DO NOT know if it has factory amplification. I am not to familiar with the options that GM offered or offers in their vehicles. I was thinking of just using a good quality line level converter to add some high end gear. You know, replace all the speakers, add subs, a basic 5 channel set up.
My main objective is to keep with aesthetics and a stock appearence by using the stock HU. I DO NOT want to spend the time or money messing with the oval ergonomic adapter for my vehicle. With that said, all aftermarket upgrades will not be considered unless someone tells me that my idea will be a waste of time.
A good line driver should send a decent signal to the amplifiers and depending on the component having some type of limited equalization or signal processing, It should sound decent.
Gentleman, fire at will!! Mystical_Ice 07-10-04, 02:55 AM i was about to reply to your PM, but since you mentioned this publicly, i may as well respond in kind :) :) :)
The opinions on the Bose systems are mixed.
Most of the newer ones actually have an equalized line-level signal running from the head unit to the little individual amplifiers for each speaker. If you do decide to go with a line level convertor (i.e. SNI-8), make sure that the wire you are tapping into is not already a line out and then make sure it's not already equalized. so yeah add a quality LOC or similar interface adaptor (like a superior Audio Control EQS), add new amplifiers and new speakers and you are good to go. As long as you have a quality interface adaptor and good speakers mounted properly, powered properly and used properly, things will be much better than the stock Bose
David Navone speaks on OEM head units:
Dave Navone, one of the premier voices in Autosound sent me suprising results as they relate to aftermarket vs. oem head units. I talked to him about my factory delco/bose unit in my Escalade and the fact that I wanted to keep it. He agreed:
Autosound 2000 Test Lab Report on OEM vs. Aftermarket Head Units
Car Audio in the 21st Century
By David Navone
The 1990s brought us OEM systems that are integrated into steering wheels, air conditioning systems, warning lights, factory anti-theft systems, etc. Not only that, but the features and benefits of some OEM systems cannot be easily duplicated in the aftermarket. For instance GM’s Driver 1 or Driver 2 preset preferences and steering wheel controls make swapping head units a difficult decision. Also many OEM in-dash decks can play a CD and a cassette. Upgrading such a deck can be a really tough decision. In fact, many OEM head units are being left in the vehicle and aftermarket system designers are interfacing components to the factory deck. There are shops that lament the fact that they can’t upgrade the factory deck, but with many new vehicles, the OEM deck will probably remain in the car until it hits the wrecking yard.
A2TL Tests New OEM Decks
But is replacing a modern deck with an aftermarket deck really an “upgrade?” We’re nearly into 2001 and our Car Sound Forum’s have been alive with questions about interfacing new OEM decks with aftermarket components. Questions about “sacrificing quality by using an OEM head” have prodded our Autosound 2000 Test Labs into examining the electrical differences between aftermarket decks and OEM decks.
For our tests we chose a new Visteon OEM deck, a new Delco OEM deck and a mid-line priced Japanese deck. (We recently reviewed this popular deck in Car Sound). The Visteon deck utilizes a 6-CD changer (CD-6) and the Delco deck is the 4185. We tested the OEM decks with a high quality interface attached in the same manner they would be used in a typical OEM upgrade. We chose Soundgate LOCHVA OEM interface devices for the tests because Rob Putman at Soundgate is our AutoMedia OEM Interface Editor. The tests were our standard specification measuring programs in the Audio Precision System II.
As we all realize, an important spec is the Maximum Undistorted Signal Level, which was 2.5 volts in the Japanese deck, 3.4 volts in the Visteon deck and 3.9 volts in the Delco deck. These readings were taken just under clipping and notice that the distortion figures are 1% or less. Distortion of less than 2% on musical program material is impossible to hear so the 1% spec is excellent.
The useable dynamic range is the difference between the noise floor and the maximum undistorted output. The Japanese deck yielded a specification of 93 dB, the Visteon deck came in at 82 dB and the Delco deck measured 93 dB. The maximum theoretical dynamic range for a 16-bit CD is 96 dB. This means that these specifications are excellent – especially for a car audio component that must contend with road – wind – vehicle noise.
The last specification we measured was the output or source impedance. The Japanese deck measured a respectable 300 ohms. Both the Visteon and Delco decks had very low output impedance measurements (less than one ohm) because of their speaker level outputs, but with the OEM interface devices installed, the specs were a little over 1000 ohms for each deck. Is this a bit high for car audio?
Output Impedance Specs
In Noise Troubleshooting 101, we learned that a high output impedance could be a source for noise. The output impedance can be thought of as a resistance (actually impedance) in series with the signal. For those readers who hate Ohm’s Law, we have can say, “The highest voltage will be developed across the highest resistance.” This means that a high source impedance could allow a higher noise level to be produced across that resistance. This last statement is also the key to the potential problem for noise.
Since the output impedance of the speaker leads of the OEM decks themselves is certainly very low, there will be very low noise levels produced on the signal path leading to the OEM interface devices. The only possibility for noise appears at the OEM interface device and on the output of the OEM interface device. This means that the speaker level signal should be routed close to the input of the aftermarket amplifier. (We recommend Unshielded Twisted Pair signal cables for this task.) Then the OEM interface device should be installed at the input of the aftermarket amplifier. If the installation is done correctly, a source impedance of 1000 ohms over a short path of 6” or so will not present a problem.
Conclusions
The specifications of the OEM decks, connected to the OEM interface devices, proved to be as good as a mid priced aftermarket deck. It’s important to correctly install the OEM interface devices, but once in place, the electrical differences are certainly not noticeable. STS 310 07-11-04, 06:14 PM I was starting to wonder about that PM Mystic as you are usually pretty quick on responses, at least to threads. Thanks. BUT, My stock is not Bose. However you did go on to address that as well.
Thanks. Mystical_Ice 07-12-04, 02:13 AM ooooh i'm sorry... i thought you said your system WAS Bose... i read wrong :p
either way, Dave Navone's article should help you on your decision well. personally, i'd say if you're looking to keep your stock appearance, then may as well keep the stock head unit, just replace the speakers, amp, etc... or if you're really daring, you could even put a second head unit in the glove compartment, etc. and have the stock one do nothing :p STS 310 07-12-04, 10:02 AM David Navone knows his stuff for sure. I will definately keep with the stock HU route. Xrayqueen 08-21-04, 12:13 PM I'm considering changing my Bose system. Reason is I want a clearer highs/harder thumping bass sound. I'm thinking of going with (2) Alpine amps (1) 4 channel and (1) mono for subwoofer. (4) Boston Acoutics satallites and Boston Acoutic subwoofer/Kicker 12inch. Also changing CD changer to Alpine so I can play MP3'S and rewriteables. All opinions will be greatly appreciated. I'm talking top up of the line Alpine. After reading Dave's article it leaves me with some ???'s :)
Peace ShadowLvr400 08-21-04, 01:15 PM I'd gut the entire sound system. Planning to myself on my 96 Fleetwood. Taking Rockford audio, going to run 2 amps, 1 4-channel for the 6x9's, doors, and tweeters, 1 2-channel amp to power a pair of 12's in the trunk in seperate boxes. Going to place them on the edge to keep a lot of trunk space. As for the head unit. It's going to be a TV/DVD/CD/MP3/AM/FM all in dash. The screen will be powered and motor out, or be hidden inside. Total of 2k for the whole sysytem installed at Best Buy. :) 7 inch screen. I'm considering changing my Bose system. Reason is I want a clearer highs/harder thumping bass sound. I'm thinking of going with (2) Alpine amps (1) 4 channel and (1) mono for subwoofer. (4) Boston Acoutics satallites and Boston Acoutic subwoofer/Kicker 12inch. Also changing CD changer to Alpine so I can play MP3'S and rewriteables. All opinions will be greatly appreciated. I'm talking top up of the line Alpine. After reading Dave's article it leaves me with some ???'s :)
Peace
You have made a very nice system selection. I'd stick to it. | |