Electronics package outputs?
1/26/11, 08:45 AM
#41
Shelby GT350 Member
Prior to that I was using JL W3 subs, MTX Thunder Pro and Xtant amplifiers, before that PPI Power Class amps, before that I was using Kenwood Excelon, Rockford Fosgate because nothing sounds as pure as the old paper coned subs. Before that I was using Alpine, Kicker and MTX Blue Thunder equipment. But most of that was stolen out of my 93 Chevy truck.
I've installed **** near everything else. Post and Pre MECP cert. I miss all of my equipment but it's a very expensive hobby and sometimes, most times, a very frustrating one. Once I get back into project mode I'll get back in the saddle, but for now, I just like to take in the only decent audio I have, the L7 system in the BMW.
5/10/11, 11:27 PM
#42
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Join Date: November 4, 2010
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Man I'm glad you guys got that taken care of.
The roll off dSINta is referring to is a simple subsonic filter. It doesn't roll off exponentially unless you are considering the logarithmic mean which is e to the x power expressed as a 10log function of decades. The so called effect can be explained by looking at a log graph (bode plot) of a filter, or sub sonic filter (a filter to keep low end out of the speakers or very low fq high pass filter) and realize the increase in gain logarithmically rolls off giving the increase in power a greater roll off (not by filter dB, by power). Say you have have a filter that is 20dB per decade (half the power per every doubling of the frequency depending on what the filter is), this, in a low pass filter will mean that if the center frequency is at 90Hz, at 45Hz the power (gain) will be halved (6dB per octave). This has nothing to do with what you hear, it's just numbers. Technically if given 1w per 1M, this would mean that it would sound 6dB below where it was before, the ear can process increments of 3dB so it would sound 2 times lower. All still in relative terms though. AC is concrete only momentarily on paper and that's about it.
So, since everything is amplified, the roll off effect is now effectively however many times the amplification. So if the amplifier were to boost the gain by 5 times, a dB/octave drop will seemingly appear (sound) 2.5 times as effective. For example, power input to the signal is boosted by 600 watts, after filter the effective power is 300 watts. I don't know that this clears up anything but since signal, amplitude, phase, power, sound pressure are all relative terms, you can't just say, oh, the more the volume goes up, the more the amplifier is suppressed. While it's somewhat and half-assed a true answer, it isn't the correct answer. An understanding of how AC filters and logarithmic scales work is what is needed to understand why the filter acts the way that it does.
I think we should all stray from some of these assumptions and misunderstandings. Most of you are on the right path and good questions and answers are given. Somethings I just can't let go so I'm sorry for my rant. If it isn't known how something works, then it is an assumption, not a fact.
Now play nice.
The roll off dSINta is referring to is a simple subsonic filter. It doesn't roll off exponentially unless you are considering the logarithmic mean which is e to the x power expressed as a 10log function of decades. The so called effect can be explained by looking at a log graph (bode plot) of a filter, or sub sonic filter (a filter to keep low end out of the speakers or very low fq high pass filter) and realize the increase in gain logarithmically rolls off giving the increase in power a greater roll off (not by filter dB, by power). Say you have have a filter that is 20dB per decade (half the power per every doubling of the frequency depending on what the filter is), this, in a low pass filter will mean that if the center frequency is at 90Hz, at 45Hz the power (gain) will be halved (6dB per octave). This has nothing to do with what you hear, it's just numbers. Technically if given 1w per 1M, this would mean that it would sound 6dB below where it was before, the ear can process increments of 3dB so it would sound 2 times lower. All still in relative terms though. AC is concrete only momentarily on paper and that's about it.
So, since everything is amplified, the roll off effect is now effectively however many times the amplification. So if the amplifier were to boost the gain by 5 times, a dB/octave drop will seemingly appear (sound) 2.5 times as effective. For example, power input to the signal is boosted by 600 watts, after filter the effective power is 300 watts. I don't know that this clears up anything but since signal, amplitude, phase, power, sound pressure are all relative terms, you can't just say, oh, the more the volume goes up, the more the amplifier is suppressed. While it's somewhat and half-assed a true answer, it isn't the correct answer. An understanding of how AC filters and logarithmic scales work is what is needed to understand why the filter acts the way that it does.
I think we should all stray from some of these assumptions and misunderstandings. Most of you are on the right path and good questions and answers are given. Somethings I just can't let go so I'm sorry for my rant. If it isn't known how something works, then it is an assumption, not a fact.
Now play nice.
And I thought that I overthink things.
7/25/11, 06:51 PM
#43
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Join Date: February 11, 2011
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Alright. Bumping this thread because it appears to be the best one on the subject.
I have the Nav headunit and need to get my amps a good signal. I'd like to an amp on my fronts and a sub in the rear, changing out the front speakers while at it.
I to know which wires to splice into and what device to get.
I'm assuming the HU has 8 pairs of outputs, 2 pair for fronts, 2 pait for rears, and then 4 pair for the DVC subs.
I have the Nav headunit and need to get my amps a good signal. I'd like to an amp on my fronts and a sub in the rear, changing out the front speakers while at it.
I to know which wires to splice into and what device to get.
I'm assuming the HU has 8 pairs of outputs, 2 pair for fronts, 2 pait for rears, and then 4 pair for the DVC subs.
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