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Re: Some amp/speaker questions- tuning it, VERY LONG Posted by Jake [Email]  (#225) [Profile/Gallery]
(more from Jake) on Mon, 22 Jul 2002 18:32:24
In Reply to: Some amp/speaker questions- tuning it (longish), Tagu, Mon, 22 Jul 2002 17:53:36 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Tagu,
What exactly are you running for speakers/subs? I see that you have a 4-channel amp, and yes, you are correct in that at different resistance (ohms) levels, the amp puts out different amounts of power. The less resistance (2 ohms has less resistance than 4) the more power the amp can push through the speaker, hence more power to a lower ohm load. However, amps are only stable down to a certain ohm level (Most mono channel sub amps are stable to 1 or 2 ohms, and most 2 and 4 channel amps are stable down to 2 ohms PER channel).. What speakers and how you have them wired up to the amp changes the final ohm load, so you'll have to let me know what you have hooked up to each channel. If you have a subwoofer, and it's Dual Voice Coil, that can get confusing too, because then you can change the resistance of the sub depending on how you wire the Voice Coils.. Anyways, about a gain knob.. A gain knob is NOT a volume control for the amp. Definitely keep that in mind. All the gain does is control the input sensitivity of the amplifier. For example; if you have the gain set all the way down, you have to turn your radio/cd player just about all the way up (depending on the voltage output of your head unit's rca's) in order to get full power out of the amp. As you turn the gain up on the amp, it takes less and less volume on the head unit to get your amplifier to full power. But you don't want to have the gain control too high, because then the speakers your amp is powering will be overpowering the rest of the speakers in the car. Another problem with having the gain too high is distortion and clipping. This is when you have the gain knob so high that the amplifier is attempting to create more power than it can, and is essentially 'clipping' the tops and bottoms off of each sound wave. Although this is good up to a point (area of a square wave is larger, i.e. more power, than a sine wave), once you have audible clipping (distortion), you can blow speakers. Anyways, to properly set your gain: have the car running, so your amp is getting the full ~14 volts rather than just the 12 it gets with the car off. Turn bass boost and gain all the down on your amp, and then turn up your head unit to the point where you would normally set the volume when you are listening to your system at a LOUD level, but where no speakers are distorting. Then sloooowly turn up the gain on your amp until you hear distortion in the speaker(s). Then turn the gain back juuust a bit until the distortion is gone. Now that channel on the amp is properly matched with your head unit so that when you turn up the stereo to where you listen to it the loudest, the amp is at it's loudest without distorting. Whether your amp is powering speakers or subs, I would advise AGAINST using any bass boost, as I find this just adds distortion to the sound. Plus the bass boost is set at only one frequency (usually between 40 and 60 hz) and thus gives your sound curve a funny bump in it, which can cause some funny sounds in some songs.. Maybe I'm just fussy.. :o) Also, if your head unit is aftermarket, I would not have the loud or bass boost option turned on to full or high. All that does it boost the bass and treble frequencies and lower volumes. This is good if you always listen to your stereo quietly, but when you turn it up it will cause distortion. Anyways, for the best quality sound you want to have your EQ on the deck fairly flat (without too much boosting or cutting in any of the highs mids or lows), and your loud on low or medium if you have that option. As far as what songs to listen to when tuning the system, I would advise just using something that is similar to what you listen to most.. If you listen to Rap, don't tune your system with classical. :o) Anyways, let me know exactly what you have for speakers/subs and how you have it all wired to the amp, and I'll let you know what ohms you are running for each channel. Sorry about the insanely long post, but I'm as much into car audio as I am into these Saabs! :o)
Good luck!
Jake
88 900S
249,000 miles
posted by 24.52.130...
, Mon, 22 Jul 2002 18:32:24 <-- Viewing This Message, Tue, 23 Jul 2002 12:38:24, Tue, 23 Jul 2002 16:47:44
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