Amplifing a signal without clipping.

[Biker 10+ year member]

So, I have done my reading and have a couple questions. I have access to an Oscilloscope and want to start from scratch.

Obviously I would like to set everything starting with my HU at 100%. That way no one can damage my ****. I have a Kenwood KDC-MP928 and the max volume is 35. Does anyone know if this HU has no clipping at 100% or am I required to scope it.

If say there is clipping at 32 or so is there anything I can put in the line to help or do I have to keep the volume below 32?

So then on to step 2 as I increase the gains to the proper voltage what do I look for as an Oscilloscope signal to see clipping? Does the round soundwave go flat or what?

And finally, according to the gain setting is it possible to go past the calculated voltage if the signal doesnt clip or is that the ideal place to stop?

Thanks Biker

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[SQChevy 10+ year member]

Well, usually the clipping from the head unit is something built into the unit and not something that you can control. (At least not to my knowledge) Find out if you head unit clips by using that scope would be my suggestion. Then once you find out the loudest the head unit can go, move the oscilliscope to the output of the amp and when you see a square wave turn the gain down until you get a sine wave again. Then your amp will put out max power at that volume and not send a clipped (distorted) signal.

 

[T3mpest 10+ year member]

So, I have done my reading and have a couple questions. I have access to an Oscilloscope and want to start from scratch.
Obviously I would like to set everything starting with my HU at 100%. That way no one can damage my ****. I have a Kenwood KDC-MP928 and the max volume is 35. Does anyone know if this HU has no clipping at 100% or am I required to scope it.

If say there is clipping at 32 or so is there anything I can put in the line to help or do I have to keep the volume below 32?

So then on to step 2 as I increase the gains to the proper voltage what do I look for as an Oscilloscope signal to see clipping? Does the round soundwave go flat or what?

And finally, according to the gain setting is it possible to go past the calculated voltage if the signal doesnt clip or is that the ideal place to stop?

Thanks Biker

Setting your gains in this manner is bad idea, IMO. No clipping at any volume, with max volume at top hu volume is going to leave you no headroom. If a track is recorded at a low volume, you'll never get any real sound out of it due to your gain structure. Not to mention it'll be a total waste of your amps power, as they'll never see enough voltage to put out any real power.

 

[DejaWiz 5,000+ posts]

So, I have done my reading and have a couple questions. I have access to an Oscilloscope and want to start from scratch.

Obviously I would like to set everything starting with my HU at 100%. That way no one can damage my ****. I have a Kenwood KDC-MP928 and the max volume is 35.

1. Does anyone know if this HU has no clipping at 100% or am I required to scope it.

2. If say there is clipping at 32 or so is there anything I can put in the line to help or do I have to keep the volume below 32?

3. So then on to step 2 as I increase the gains to the proper voltage what do I look for as an Oscilloscope signal to see clipping? Does the round soundwave go flat or what?

4. And finally, according to the gain setting is it possible to go past the calculated voltage if the signal doesnt clip or is that the ideal place to stop?

Thanks Biker

1. I've never known about any HU's that don't distort in the upper volume range. It's just somthing that happens. Might be at 75% max, might be at 80% max, might be at 90% max. It's a somewhat safe assumption that distortion typically starts around 75% of max volume.

2. Nope, you're going to have to keep the volume below the point of distortion. And severe/deadly repercussions should come to anyone that damages your equipment from abusing your system.

3. This was answered by SQChevy. Sine wave = good, square wave = BAD!

4. Yes, it is possible to go past the calculated voltage if the signal doesn't clip.... just be careful how much power you send to your speakers. They may end up hating you.

EXAMPLE:

Since you 'scoped your HU, you know that 28/35 volume (approx 80%) is the max you can go before distortion results.

Now say you have an amp that can put out a solid 4x150W RMS at 4 Ohms. Your speakers are 4 Ohms and rated at 80W RMS each, so you do the following:

SQRT(watts * ohms) = voltage

SQRT (80 * 4) = 17.889V

A few days later you recently find out on an internet forum that your speakers have been know to do well on 135W RMS each, so you recalculate:

SQRT (135 * 4) = 23.238V

A DMM is utilized and you adjust the gains until the amp outputs read approx 23.2V each.

You now have a little higher output at the same HU volume than you did before.

...I know this doesn't solve the problem of kids/friends/people blowing up your system every time they get in your car, so ban them from it. If they're not going to listen to you, then they don't get to listen to your system. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[Biker 10+ year member]

100% answers my questions. Thanks everyone

Biker