JL Audio Clean Sweep... almost perfect?

[Gawdly]

I'm probably over simplifying... or maybe I don't fully understand this thing yet, so let me first outline my understanding.

Basically this device calibrates itself to correct EQ adjustments being made by the factory head unit. It then presents the new signal to your amplifiers with no EQ adjustments. I know this isn't exact, but is this in the ballpark?

I also seem to be reading that it does its calibration based on the volume level at the time of calibration. So it is creating an unadjusted signal at that volume level. Correct?

So... once you calibrate and have everything setup, you are clean at that volume level from the head unit. You stay clean if you adjust volume by way of the little clean sweep knob. If you adjust the volume at the head unit, the signal coming from the head unit can change which changes the final signal from the clean sweep as well. Am I still on track?

Here's the "almost perfect" part. I don't want to use the clean sweep knob. I want to use my head unit and steering wheel audio controls for volume.

And here's the "I'm probably over simplifying" part. If you can design a unit to correct at one volume, why can't you design one to correct across all volumes? Hear me out here...

Add memory and processor power to the unit to accommodate the following:

1. At calibration, repeat the process at multiple points across the volume scale of the head unit. Measure volume by signal output and the needed correction for each point of volume and store in the unit.

2. Have the unit connect the dots to create a map of corrections across the volume scale.

3. Enable the unit to read signal output to interpret selected volume at the head unit.

4. Have the unit adjust corrections in accordance with it's calibration map as volume is adjusted at the head unit.

Someone please tell me that I'm not an idiot or a genius and that they are already working on this.

[John M]

Well, your thoughts on how it works are right -- you get a clean signal at one volume level to do with as you please.

 

It'll never work for multiple volume levels because the aftermarket device has no idea where the volume knob is positioned at any given moment. It can't go by audio level because it could be a quiet part of a song, between songs, etc.

[Gawdly]

Well, your thoughts on how it works are right -- you get a clean signal at one volume level to do with as you please.

 

It'll never work for multiple volume levels because the aftermarket device has no idea where the volume knob is positioned at any given moment. It can't go by audio level because it could be a quiet part of a song, between songs, etc.

 

Ah... there had to be a flaw.

 

Gotta be a way to overcome that though... hmmm.

[Boulderguy]

The real flaw is the HU's EQ curve - it's not static. It changes given different volume settings. If your HU processed the signal in the same way at any amplitude the second volume knob wouldn't be necessary. The Subaru HU doesn't do this. See attached pic -

 

http://i44.photobucket.com/albums/f29/Boulderguy10/OEMEQcurves.jpg

[Chief_Wiggum]

It mashes them up because the stock speakers can't seem to handle the full range output at all volume levels.

 

I really like my CS, but I have a couple gripes.

 

- The volume knob feels cheap. It flops around a bit, feels more like a cheap potetiometer than a solid volume knob.

 

- the CS doesn't do anything with your aux signal. Since I listen to XM %90 of the time, the CS becomes a glorified volume knob (see complaint above).

 

- Your head unit fader, tone controls, etc don't do anything for the aux signal (obviously), so you need to make sure the amp you get is flexible enough that you can control the system using it rather than a head unit. The CS really makes you distribute system control rather than consolidating it like an aftermarket HU would allow you to do.

[Boulderguy]

That's one of the reasons I never went that route, altho I still consider it. I use an Ipod 99.9% of the time routed thru a signal processor with it's own volume knob, it's worked great. I sometimes think I'd like a clean, non-MP3 source but I'm so happy never messing with CD's anymore that I doubt I'll ever do it.