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40Hz Sinewave of Jl Rd 1000/1


Qwiz
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17 minutes ago, Qwiz said:

Does this look legit? Video

Are you using any line out converter or anything between the head unit and the amplifier? 

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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14 minutes ago, Qwiz said:

No. The source signal is coming from an 80Prs, which was beforehand measured and clean all the way. If you don't believe me, I could make a separate video.

I believe you. I was just asking that maybe that noise was coming from something else. 

How close is your power wire to your RCA's? If they are ran close together, noise can bleed over into the RCA's 

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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Posted (edited)

Not the case.

 

I hooked up an AB Class afterwards and the sinewave was clean.

 

I am curious to find out what´s causing this dirty output? I mean, it is the amp causing it, but what exactly? Is this a common issue with some D class amps? It looks desecrated, you know?

Edited by Qwiz
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I'm not an expert, but from what I've seen on some YouTube videos is when a sine wave looks like that, that means along with the single frequency tone you're using, you're also getting another frequency or frequencies finding there way into the wave. 

I would say that if you used the same tone, same head unit, same wiring, same everything on a different amplifier, and the wave didn't look like that, the only culprit could be the amp. 

JL is usually very good with their sound quality coming from their components. So I find it strange that the culprit is the amplifier. That's not me saying it can't be the amplifier. It sounds like it is. No company can be 100% perfect, and I don't know what all your settings are on that amplifier, but I would get into contact with JL directly. Maybe even send them a picture or even that video and see what they say. If it is, in fact, the amplifier, they need to send you a new one. 

Edited by Dafaseles
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2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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Is it a 0db tone? Or? Is it off a app, or off a disc? 

 

Edit- my prs, wasnt clean to full

 One click down from max was. Also, any filters applied? Anything adjusted or all completely flat? Shit head questions i know, but it all comes into play here. 

Edited by Kyblack76
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Posted (edited)
17 hours ago, Kyblack76 said:

Is it a 0db tone? Or? Is it off a app, or off a disc? 

 

Edit- my prs, wasnt clean to full

 One click down from max was. Also, any filters applied? Anything adjusted or all completely flat? Shit head questions i know, but it all comes into play here. 

Yep it´s a 0db Tone off of a USB Stick. No filters applied.

 

The signal from the PRS was tested prior and it was clean all the way to max.

 

After the JL amp test, I hooked up a class AB from Mosconi, whose results were very clean, as expected.

 

The JL RD 1k amp I bought it 3 years ago and I suppose its output was like this since the beginning. Back then I didn´t have the O scope, nor any useful knowledge.

 

LE: Another thing to mention is the clip indicator on JL does NOT detect such desecrated distorsion. It only lights up when the wave is fully destroyed. It always sounded funny to me this amp, nevertheless I thought this is how it is supposed to be, which is definitely not the case.

 

I would argue the FFT function of the signal on the JL, which this scope is not capable of.  The amount of harmonic distorsion expressed by this amp is mos def off the chart.

 

PERHAPS might be worth mentioning that one day bass went off for "no reason". Turned out that the AMP GROUNDWIRE fell off while driving, i.e. disconnected, flew off from its socket due to rookie installer skills. The positive was still connected. So I went and disconnected the negative from the BATTERY and rewired everything back. It seemed to be fine. But maybe, just maybe, this DID something bad to the internal circuit. The amp was handled with proper care this whole time, I did not harass it in any way or form.

Edited by Qwiz
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Posted (edited)
On 3/31/2022 at 8:37 AM, Kyblack76 said:

Ahhhh,.. i got ya now. Seems you know what your doing, and have it more than handled. Best of luck mate. 

KB

Thanks mate.

 

In my other posts I raised other issues connected to this, which to this day no exact answer was found to.

 

Basically the problem in this car is the sub output between 25-80Hz. No matter the amp/sub, a linear bass output could not be reached.

 

Other than that, merging with the mains has never happened.

 

For example, from the driver or passenger position, with any phase/time alignment settings, we have cancellation -6-10db between 44-46Hz and 58-80Hz respectively. Crossed high (200Hz) for this particular test (sinesweep 20-80Hz) with no mains in play to potentially excuse the latter cancellation. Acoustics?

 

I would also point out that any sub (located in the trunk, or anywhere in the car, no matter its firing position) on any amp plays (alone without the mains) muffled. It never sounded clean.

 

There is no noise in the system. I might be relocating the power and ground wires for the headunit, by making them common to the amp distro block. May not help at all but why not.

Edited by Qwiz
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