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Old 11th July 2006, 18:53   #61
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thanks @Sam , @lbm .. this linky is quite detailed for me .. and I'll need to re-read it a few times ! but have got the general drift ...
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Old 14th July 2006, 15:31   #62
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where is the A pillar in my car.. ( i think it is one of the front 2 pillars holding the roof, right???)
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Old 14th July 2006, 16:15   #63
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the red arrow is pointing the a-pillar


Pic edited by gunbir
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Old 17th July 2006, 16:53   #64
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Quote:
Originally Posted by shuvc
What is GAIN ?
My active sub has a control for it.
Its the impedence matching control knob. between the headunit and the amplifier
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Old 17th July 2006, 17:10   #65
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Default This is a glossary, a sticky. Let's give it some respect.

Quote:
Originally Posted by kURETI
Its the impedence matching control knob. between the headunit and the amplifier

I've explained in very simple terms what a gain control is (see post #60). If you'd like more info on it, PM me, I don't wanna confuse newbies.

It is not an impedance matching control knob.

Secondly, sorry to sound like a moderator, but someone asked a question about the A-pillar and LBM very kindly posted a picture explaining what it was. That should have closed the issue.

I request all to refrain from casual "yes/no" posting here. This is a reference sticky thread please let's please just keep it that..

I request Navin(since he is most qualified) to remove all irrelevant and technically incorrect posts. This incorrect information will mislead those that do not know enough about audio.

Last edited by Sam Kapasi : 17th July 2006 at 17:14.
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Old 17th July 2006, 17:33   #66
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Sam!
Sorry for the casual post like yes or no.
I will get back to you on the gain control
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Old 17th July 2006, 17:48   #67
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Hi sam,
At first this gain control was asked by an BHPian and not a newbie

Gain.
Generally this is the shorthand for voltage gain. Its a measure of the amplification factor of an amplifier, or the output voltage divided by the input voltage. thus i can say , 10Volts out for an 1volt in is a gain of 10

Amplifier input sensitivity is the voltage required to produce rated output.
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Old 17th July 2006, 18:41   #68
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Quote:
Originally Posted by kURETI
Its the impedence matching control knob. between the headunit and the amplifier
gain cannot be equated to impedance matching. impedance matching as it normally understood is done via things like transformers (passive) and opamp circuits. One can even use a DSP controlled circuit to do this but impedance matching is not a gain control.

Gain control (esp as it is applied to ICE) is better explained here
http://www.teamrocs.com/technical/pages/gains.htm

I understand it as a voltage divider not an impedance matcher.

A "BHPian" might be an ICE newbie. Someone who knows the intricate details of engines and tranmissions might not have similar knowledge about ICE. So by a Newbie we (atleast I am) refering to ICE newbies. Why I am a "Moderator" and can still consider myself as a newbie when it comes to Engines and Tranmissions and for that matter if I were to compare myself to the Gurus I might be a relative newbie with respect to ICE as well.
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Old 18th July 2006, 11:20   #69
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Quote:
Originally Posted by navin
gain cannot be equated to impedance matching. impedance matching as it normally understood is done via things like transformers (passive) and opamp circuits. One can even use a DSP controlled circuit to do this but impedance matching is not a gain control.

Gain control (esp as it is applied to ICE) is better explained here
http://www.teamrocs.com/technical/pages/gains.htm

I understand it as a voltage divider not an impedance matcher.

A "BHPian" might be an ICE newbie. Someone who knows the intricate details of engines and tranmissions might not have similar knowledge about ICE. So by a Newbie we (atleast I am) refering to ICE newbies. Why I am a "Moderator" and can still consider myself as a newbie when it comes to Engines and Tranmissions and for that matter if I were to compare myself to the Gurus I might be a relative newbie with respect to ICE as well.
accepted and neither its know as volume control!!!!!!!!!!
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Old 18th July 2006, 11:31   #70
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Quote:
Originally Posted by kURETI
accepted and neither its know as volume control!!!!!!!!!!
Navin Hi!
Follwed your link still somehow I cannot accept this perticular word like Volume control - for Gain I think in one of the site I had read a proper meaning for Gain need to find this - shall get back on this again soon.
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Old 18th July 2006, 13:03   #71
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Kuerti, it says "Gains are like little volume controls" not "Gains are volume controls". Most volume controls use potentiometers. http://sound.westhost.com/pots.htm

Last edited by navin : 18th July 2006 at 13:05.
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Old 18th July 2006, 15:10   #72
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I'm not even going to google this one and check any site for it.
Gain controls, control the level of amplification gain that the pre-output level goes through using the power amplifier circuit.
That is a lot like how the volume control functions. Perhaps the po

My explanation was for someone who didn't know audio, and I'd like to think it was very simple and not incorrect. Again does function as a secondary, a "master" (if you will) volume control.This isn't a point to be proven here, nor is this a quest for correct terminology to be used in conjunction with the explanation of "gain"

The only reason i raised an eyebrow was for the use of the word "Impedance matching"
Gain has absolutely nothing to do with impedance matching. It is in fact, a voltage divider as my Budda rightly pointed out.. In fact, navin would agree here, the only "impedance matching" that can be done is with the use of line-matching transformers, a concept rarely used in automotive sound.

Ergo, there is no such thing/concept as an "impedance-matching control knob". That statement is incorrect, your honour. Gavaahon ke bayaanat pe etc etc....
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Old 20th July 2006, 12:10   #73
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Whats subsonic filters for?
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Old 20th July 2006, 12:22   #74
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Again, I will explain quite simply, what I know. The rest I guess some people can google around lol

Sub - means below. Sonic means related to sound.

Human hearing theoretically cannot respond to frequesncies below 20Hz. However some sounds do extend below 20Hz and since we cannot hear them, however the speaker does reproduce them, thereby doing "work" which is not required.
Also very low frequencies can tend to damage the driver.

A filter, used to cut off frequencies below the human hearing range is called a subsonic filter.

However when I was in audio college, it was debatable. There are many that believe that even though theoretically we should not be able to hear below 20Hz, we do respond to those frequencies. That of course is a discussion for another thread.
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Old 20th July 2006, 13:14   #75
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Quote:
Originally Posted by jkdas
Whats subsonic filters for?
Ok, I don't want to scare you or anything so I'm keeping things simple. I wonder why Navin has to say that of me whenever I'm feeling a bit diligent, which is anyway rare.

Typical power amplifiers have a frequency response of about 5Hz to 100000 Hz, and sometimes beyond. This is not a very intended feature, but a result of the charachteristics of the components used to build one. Subsonic frequencies are defined as those frequencies that lie below the human audible frequency range, so typicaly below 20Hz. So if the music you play has some subsonic frequencies, which you can't hear, there is no point tiring your amplifier by getting it to amplifying those frequencies and thus running short of steam in the audible band. So you can engage the subsonic filter switch to filter out this part. This makes things easy on the amp. I would think that it is a very essential feature for a subwoofer amplifier.

Additionally, when you are driving a subwoofer in a vented enclosure, the sub could ruin itself with overexcursion when fed with signals below the tuning frequency. A variable frequency subsonic filter can be employed to cut out these frequencies and prevent damage to the driver.

In both cases, the subsonic filter acts like a high-pass filter.

Some may argue that they can hear frequencies lower than 20 Hz, and above 20kHz and so you shouldn't shut out the subsonics and blah blah blah. I have heard reputed individuals from the field make innumerous arguments about claims that they have felt 5 Hz and so on. 5 Hz is also the wave that runs through a 747 when the aircraft door is slammed shut. Well, you sure can hear that due to the high frequency content comprising that sound, and if you're lucky, you would probably feel it too, but there's a a one in a zillion chance that you'll miss it because it takes a really powerful 5 Hz wave to pressurize a cabin the size of a 747! Most individuals I know, and who claimed to have beyond perfect hearing have failed miserably when put to a blind test, not knowing what's playing and usually haven't been able to even distinguish vastly different drivers playing in the same environment. You can't blame them, they have also always insisted that clipping distortion kills speakers, without knowing exactly why!
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