Where to draw the signal from for the sub?
02-26-2008, 03:48 PM
#31
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Hey dillyyo, now just to start by saying I am not looking to battle, just get the facts straight. I have read up on electrical theory as you had suggested, and from what I have read it states that although the ground and positive have the same current running through them, the positive is more concentrated. The ground/chassis being that it is so large has little EMF associated with it. The positive being that it is so concentrated has more of a chance to create an EMF, since it has a smaller aperture to travel through as compared to the whole cars chassis. I also found that even though the car is DC it still has a small amount of AC voltage from the alternator remaining in the system. And from what I have read, since there is an AC voltage in the power wire, an AC current can be induced and added the the sound signal. Which in turn is amplified along with the music.
Now I am not negating the fact that a bad ground can be a problem with noise. And that it should be your first place to check. I am just trying to get rid of any possibility of noise being introduced into the signal from the very beginning.
Now I am not negating the fact that a bad ground can be a problem with noise. And that it should be your first place to check. I am just trying to get rid of any possibility of noise being introduced into the signal from the very beginning.
Remember one fact....there is ALWAYS noise present in a signal. The point is whether we can hear it or not. What I am telling you is that by running all of your wires together, the inherent noise that is DEFINITELY there, will not be audible and present. Think of it this way....most noises like ALT whine and even static noise are present when the volume is at zero or very low. Well, if there is no or barely any current flowing through the power wire, how is the noise being introduced?
The fact is that it is not due to the power wire. I have taken RCA's (radio Shack and top quality) and speaker wires attached to speakers and wrapped them around power wires. I have never had any noise transmitted through the speakers. try this experiment if you do not believe me and also think about what I said with the volume being down and still getting noise.Also remember that we are not talking about components noise floors. All systems have background noise and is the reason why noise gates were implemented sometimes. This has to do with the components themselves and their signal/noise ratios being optimized.
And getting the facts straight is all part of the learning process. I might not be able to in depth describe and convey all electrical theories and how they relate to car audio, but I have colleagues and friends who have and can. After many years of learning from audio nuts who were engineers and just plain geeks I guess, a lot of information has absorbed into my head. Being a scientist, I don't like to just go by what he or she said. I like to prove it myself or at least have it explained to me in-depth so I can break it down and absorb it. Hopefully this helps.
Last edited by dillyyo; 02-26-2008 at 03:52 PM.
02-26-2008, 04:38 PM
#33
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Preamp signal and unbalanced vs. balanced?
Hey guys,
Given i have two audio minds with some real experience here, thought i would ask these questions.
1. What is the difference between balanced and unbalanced inputs? (I saw an amp that has both. The balnced being for "oem interation". Another amp says, pre-amp and speaker level inputs) Are they basically saying the same thing? And lastly of course, which inputs would me needed to recieve rca's tapping the woofer feed go into? (Just wondering once i tap the line which kind of inputs i should feed it into, but think i got it now. It's a line level signal so should be fed into the RCA jacks.)
Thanks again to both of you for all your input so far! Now i'm feeling like i have no reason to go to an installer! If either of you are in the southbay sometime drop me a line so i can buy you a drink!
Given i have two audio minds with some real experience here, thought i would ask these questions.
1. What is the difference between balanced and unbalanced inputs? (I saw an amp that has both. The balnced being for "oem interation". Another amp says, pre-amp and speaker level inputs) Are they basically saying the same thing? And lastly of course, which inputs would me needed to recieve rca's tapping the woofer feed go into? (Just wondering once i tap the line which kind of inputs i should feed it into, but think i got it now. It's a line level signal so should be fed into the RCA jacks.)
Thanks again to both of you for all your input so far! Now i'm feeling like i have no reason to go to an installer! If either of you are in the southbay sometime drop me a line so i can buy you a drink!
Last edited by cartman13; 02-26-2008 at 10:54 PM.
02-26-2008, 05:21 PM
#34
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Hey guys,
Given i have two audio minds with some real experience here, thought i would ask these questions.
1. What is the difference between balanced and unbalanced inputs? (I saw an amp that has both. The balnced being for "oem interation". Another amp says, pre-amp and speaker level inputs) Are they basically saying the same thing? And lastly of course, which inputs would me needed to recieve rca's tapping the woofer feed go into?
Thanks again to both of you for all your input so far! Now i'm feeling like i have no reason to go to an installer! If either of you are in the southbay sometime drop me a line so i can buy you a drink!
Given i have two audio minds with some real experience here, thought i would ask these questions.
1. What is the difference between balanced and unbalanced inputs? (I saw an amp that has both. The balnced being for "oem interation". Another amp says, pre-amp and speaker level inputs) Are they basically saying the same thing? And lastly of course, which inputs would me needed to recieve rca's tapping the woofer feed go into?
Thanks again to both of you for all your input so far! Now i'm feeling like i have no reason to go to an installer! If either of you are in the southbay sometime drop me a line so i can buy you a drink!
In simple terms, a balanced line carries a signal of opposite polarity to the other signal and drives identical impedance loads. This inverse relationship allows for any noise that is present in BOTH signals to cancel each other out and not be heard. There are three wires, ground and 2 signal wires in inverse relationship.
In an unbalanced line i.e line level RCA signals there is not an inverse identical signal. There are two wires, signal and ground and very different impedence relationships exist to the reference.
Line level is a low level input meaning like RCA's or something with similar voltage (millivolts) and speaker level is like from a HU that directly drives speakers with an internal amp measures in Volts. IF the signal is unprocessed then it is ALWAYS better to use a speaker level signal since a higher voltage signal will have a better signal to noise ratio.
I dont understand your last question so please retype.
Last edited by dillyyo; 02-27-2008 at 12:29 AM. Reason: typo
02-26-2008, 06:42 PM
#35
I appreciate the info dillyyo. And now I know a little more about the subject. As like you, I was going off info that I had absorbed thru trial and error and from what I have read. The first couple of installs that I had performed I had run into noise, and splitting the wires had helped a bit with my applications.
So from then on I took the extra 20 mins. to run the wires done each side to help lesson the chance of noise. And we all can learn from this discussion.
So from then on I took the extra 20 mins. to run the wires done each side to help lesson the chance of noise. And we all can learn from this discussion.
02-26-2008, 08:13 PM
#36
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I appreciate the info dillyyo. And now I know a little more about the subject. As like you, I was going off info that I had absorbed thru trial and error and from what I have read. The first couple of installs that I had performed I had run into noise, and splitting the wires had helped a bit with my applications.
So from then on I took the extra 20 mins. to run the wires done each side to help lesson the chance of noise. And we all can learn from this discussion.
So from then on I took the extra 20 mins. to run the wires done each side to help lesson the chance of noise. And we all can learn from this discussion.
I too use to do what you did with installs, but after more experience, further experimentation and many discussions, I soon learned that the noise was almost always attributable to other factors. I say almost because sometimes I changed a few things and never could say whether it was definitely one thing or the other.
So now, if I have a problem like that my first recourse of action is to run temporary wires outside the car directly from the source or battery and se if it goes away or not. Hope this helped!
02-27-2008, 12:26 AM
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02-27-2008, 05:15 PM
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Family and acquiring all of my equipment takes some time. If you have any questions or need help them post and I will share what I can and it will be searchable for any other members.
02-27-2008, 09:02 PM
#41
Yes and no. A Cleansweep and 360 contain a Hi-low converter, but are more than that with the 360 having the most features. A hi low converter is a device that converts speaker level signals (say from an amp to the speakers) to RCA or line level inputs (low level). A line driver does exactly the opposite as a Hi-low in that it takes a line level or low level signal (RCA) and converts it to a high voltage (hi level) signal.
DSP's like Clean Sweeps and 360.1 were introduced since many people wanted to retain their OEM HU, but a lot of times these signals were already processed from the HU. Clean Sweep was first and what it did was take this processed hi level signal and then flattened them out and summed them together. This way you could add after market systems and not be stuck with the BS frequency responses the OEM systems had been putting out. Then 360.1 came out with other things besides this signal summing/flattening, like time alignment.
In out Bose system, and most modern Bose systems if I remember correctly, the signal processing is done in the amp, not the head unit. So from the HU to the amp, you have a clean relatively flat signal that can just be hooked up to an after market amp as if it were coming from an after market head unit. Someone can waste money and put a Clean Sweep AFTER the Bose amps and flatten the response, but Bose changed the response so it worked well with its speakers in our particular car. Anyone that is throwing in an after market amp and speakers, whether thats just a sub and amp or many speakers and many amps, the signal before the Bose amps can be tapped and will provide a solid signal from the OEM HU and still maintain all OEM functioning. That is the main point of keeping the OEM HU, right?!
DSP's like Clean Sweeps and 360.1 were introduced since many people wanted to retain their OEM HU, but a lot of times these signals were already processed from the HU. Clean Sweep was first and what it did was take this processed hi level signal and then flattened them out and summed them together. This way you could add after market systems and not be stuck with the BS frequency responses the OEM systems had been putting out. Then 360.1 came out with other things besides this signal summing/flattening, like time alignment.
In out Bose system, and most modern Bose systems if I remember correctly, the signal processing is done in the amp, not the head unit. So from the HU to the amp, you have a clean relatively flat signal that can just be hooked up to an after market amp as if it were coming from an after market head unit. Someone can waste money and put a Clean Sweep AFTER the Bose amps and flatten the response, but Bose changed the response so it worked well with its speakers in our particular car. Anyone that is throwing in an after market amp and speakers, whether thats just a sub and amp or many speakers and many amps, the signal before the Bose amps can be tapped and will provide a solid signal from the OEM HU and still maintain all OEM functioning. That is the main point of keeping the OEM HU, right?!
02-28-2008, 10:00 PM
#42
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Are you 100% certain that our Bose system EQ's at the amps and not at the head unit? If so, than a DSP wouldn't be absolutely necessary, although a 3Sixty.2 is still going to be a future part of my system for the near infinite tuning capabilities. But if the preamp signal is completely clean, I can add it later since I will be replacing the whole Bloze POS system anyway.
Yes. DSP functionality takes place in the Blose amps. Clean low level signal pre-amp.
If you really want functionality and not worried about multi channel format i.e. JBL MS-8 then you need to take a gander at the Zapco DSP6-SL. It's what I will be getting in a couple of weeks!
02-28-2008, 10:50 PM
#43
Hey dillyyo... If you have a second... can you maybe snap a pic or do a quick write up on just the "getting a RCA signal" to the amp.... If you have time... I know you said you wasnt installing yet but you would look at something for us if needed...
Thanks bro!
Thanks bro!
02-28-2008, 11:43 PM
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Look at this link and it describes almost exactly what I am telling you what to do, minus the single phono jack plug.
http://www.librarysmith.co.uk/empath...elp=cablehowto
Only a couple things to note though.
Get better RCA plugs from this link:
http://www.partsexpress.com/webpage...._ID =125&SO=2
When soldering your RCA's to the positive and negative wires from the HU, solder the positive to the CENTER connector of the plug and the negative to the outside connector. In other words, you want the penile part of the plug to be connected to the positive signal from the HU and the the wide outside ring of the plug to be connected to the negative feed from the HU.
Pull the wires from the input of the amp and solder the RCA right there, unless you need longer wire than you will have to use different wire to make it longer and then solder the RCA's to the extension. Remember, there are 8 wires coming from the HU: FL, FR, RL, RR, a positive and negative for each. If you are keeping all of your speakers and just trying to add a sub and amp, then you need to pick a pos and neg set to tap into. Realize though that you will be only taking signal from one channel, but won't really matter since sub frequencies are usually run mono.
Hope this helps you and if not, shoot away with questions and I will try and answer them.
After the soldering is done, you can use some heat shrink and techflex to cover the joining area between the wires and where the RCA meets. They can be gotten from parts express.
Now, if Bose is fibbing and they Do have RCA connectors going into the amp, then all of this is not necessary unless you are keeping all of your speakers running and then you would still need to tap into a set of the wires. From my experience and from what Bose told me, there are just wires with bare inputs going into the amp, via a plastic plug. Please also takes pics if you don't mind and post them.
Last edited by dillyyo; 02-29-2008 at 12:40 AM.