oscilloscope help

[nauc 10+ year member]

and, what does that prove exactly? being able to play a 0dB sinewave at full power without clipping?

yes, which means when you play music, attenuated or NOT, youre not clipping the signal, savin your speaker unless youre using a to big of an amp

 

[photocrazy8 10+ year member]

i agree with nauc that its good to set it so you can save you sub and front stage, but would the level of your gains effect your power draw, because i cant seem to shake this voltage drop problem.

 

[helotaxi 5,000+ posts]

Your gain setting is probaly not what is causing the voltage drop. I would be more inclined to believe that it's an electrical connection problem somewhere.

 

[helotaxi 5,000+ posts]

but that completely depends on the input signal to the amp.... //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif
you cant set the amp for the maximum, unclipped output, unless all you're playing is sinewaves, which you're not...

so, its completely pointless.

How would you suggest setting them then? Totally by using the least precise instument available: your ear? What recording should you use? What if you put in something that is recorded at a higher level later?

The point of using a scope (DMM is only any good if you know for a fact that the amp will produce its rated power) to set gains is to make sure that no matter what source material you feed the amp, it won't clip the signal. If you absolutely must have the extra dB or two between the test tone and the music recording, get a bigger amp. Fact is that with music, you probably won't see but about a quarter of the power from an amp and close to RMS power during transient spikes. If you tune the gain using music by ear until you hear distortion, you have it set well past the point of clipping and every transient will be fully clipped.

 

[photocrazy8 10+ year member]

Your gain setting is probaly not what is causing the voltage drop. I would be more inclined to believe that it's an electrical connection problem somewhere.

ok, so what do you think would be my problem with my electrical? all info is in my sig...

 

[T3mpest 10+ year member]

How would you suggest setting them then? Totally by using the least precise instument available: your ear? What recording should you use? What if you put in something that is recorded at a higher level later?
The point of using a scope (DMM is only any good if you know for a fact that the amp will produce its rated power) to set gains is to make sure that no matter what source material you feed the amp, it won't clip the signal. If you absolutely must have the extra dB or two between the test tone and the music recording, get a bigger amp. Fact is that with music, you probably won't see but about a quarter of the power from an amp and close to RMS power during transient spikes. If you tune the gain using music by ear until you hear distortion, you have it set well past the point of clipping and every transient will be fully clipped.

Yes, but setting using a 0 db test tone has the exact opposite problem. You'll never get anything near full output while playing actual music. Most of the systems I've seen set with an O-scope produced lack-luster results. For actual music people ended up turning the volume up fairly high just get the impact they wanted. If something was recorded at a low volume to begin with, forget about it! The car environment is not a quiet place. Your constantly competeting over road noise, even in a well deadened daily driver.

 

[helotaxi 5,000+ posts]

Check each section of wire and each connection for voltage drop. If the amp is drawing 180A at full tilt (which actually does sound a bit high with music so the gains might be off) then 1/0 should give you about 1V of loss. The fact that you are seeing lower than 12V with the engine running means that you are experiencing losses elsewhere, or your alt is not putting out the amperage that it should causing a voltage drop (this will also cause your amp to draw more current BTW). Checking your gains won't hurt, but a DMM should be all you need. You are looking for about 63V assuming that you have a D2 XXX wired to 4 ohms (no reason to wire it otherwise with that amp). But I think you have a bad connection somewhere as well.

 

[helotaxi 5,000+ posts]

Yes, but setting using a 0 db test tone has the exact opposite problem. You'll never get anything near full output while playing actual music. Most of the systems I've seen set with an O-scope produced lack-luster results. For actual music people ended up turning the volume up fairly high just get the impact they wanted. If something was recorded at a low volume to begin with, forget about it! The car environment is not a quiet place. Your constantly competeting over road noise, even in a well deadened daily driver.

This is the exact reason people can get away with running double RMS to their speakers and subs. Music is nowhere near 0dB. That is a given. As long as there is no clipping, what's the harm in turning up the volume knob, that's what it's there for last I checked. If you set the gain totally by ear, now you have to worry about clipping when you inevitably want to turn it up a bit. If everything is configured correctly and the components are well matched to each other, you should not have a want for more volume or have to worry about clipping either. If you are getting weak results from systems set up with a DMM, then you eaither don't have enough power in the first place or you have an irrational fear of turnig up the volume even though you know it is safe to do so.

 

[DBfan187 5,000+ posts]

3:1 ratio kicks ***!

read up - http://www.carsound.com/forum/showthread.php?t=8910&highlight=structure