Can someone explain Clean Sweep volume control?

[Powerman]

What I want to know is, if the volume control knob for a Clean Sweep is a pass through, or does it amplify?

Meaning, if I set the head unit volume at 75%, then turn the CS volume all the way up to 100%, what is happening?

Am I allowing 100% of the 75% head unit signal through to the amp? Or, am I amplifying that 75% signal 100% and therefore should never turn my CS volume up past 50% to avoid blowing anything up?

See what I mean? If it is just a pass through, I can set my HU volume to a point, then turn up my CS volume 100% so that my amp does most of the work instead of the HU to get volume. Right now I turn my HU up to half way and then my CS to about half way cause that is what I have always known.

Thank you.

[axis008]

I don't exactly know the answers to your questions, but perhaps this might help..

When setting up the CS, you set your OEM headunit to a certain volume level (say 25). Then you let it equalize it or whatever the CS set up does.

Then JL recommends you normally adjust volume using the CS knob, instead of the OEM knob.

After setting up the CS to OEM headunit volume level 25, when adjusting the OEM knob, to say level 15 or 30, the OEM headunit changes the equalizer sound curves, meaning the sound isn't equalized like at level 25 (hence the reason to use the CS volume knob).

Search posts from "msmith". He is the VP of marketing for JL. He posted a bunch of stuff on our boards including various graphs using CS in his LGT wagon.

[Powerman]

Thanks for the response. I actually didn't know what a Clean Sweep was and then I read all about it from MSMITH right here on our very own LGT.

What I am asking , using the proper terminology, is whether the CS volume is active, or passive. I did talk to the shop I had install the sub. They said my sub volume control is passive and will allow 0-100% of the CS signal through. I only had the sub volume up to 50% not knowing what I was actually sending to the sub amp.

They do sell JL stuff too, and the shop at least told me that the CS is a active volume control. That when the calibration is done on the CS, not only is response EQed, but signal strength from the HU is compensated too to a standard input signal strength. I don't know if that is true. Bottom line though is that if I set the HU at 25 and then turn up the CS to 100%, that would be very bad.

I will still talk to JL Audio about it at some point. If anyone here knows what I am getting at and can explain better I'm all ears.

[mwiener2]

I can turn my CS volume all the way up. My eardrums start to bleed though. But it's really clear with no distortion.


Since it's a signal processor, it's an active volume control... as opposed to a passive which would be a resistor that lowers volume by upping the resistance.


I think your audio shop is wrong about your sub as well. That may be active. It depends on if that control is changing bass boost or gain on the amp.

A good example of a passive volume control would be the volume knob found on a pair of headphones.

[Powerman]

Well I am going to talk to the installer tomorrow to find out how he put the sub control knob in. Looking on the sub amp there is nothing plugged into the line level control. And yes, besides my equipment, it would be unpleasant to my ears to turn the CS all the way up. What did you calibrate your head unit to mwiener2? I have been running mine at 25, but not really sure what the previous owner calibrated it at.

[mwiener2]

I calibarated mine at 15. Everyone else and their mom is in the 20's, but 15 worked best for me. I dunno.

[Powerman]

Well I talked to JL Audio. I guess I am just making this too complicated. Yes the volume control is active and amplifies the input signal. However, the amp is still the amp and can only put out what it can put out. as long as the head unit is clean and not clipping the Clean Sweep can use it. Turn up the CS as much as I can stand and as long as my amp isn't clipping then I'm good to go.

The JL guy did say that the Clean Sweep does NOT reduce, or compensate the head unit signal to a standard strength output signal as the stereo shop explained. He said it is sort of true, but not the way they explained it so just forget about all that stuff.

I am happy cause I have gotten braver with the volume. I am only putting out 75 watts/ch. and that is what my speakers can handle. I am at the limits of what is comfortable for me and everything is still crystal clear. Of course that brings up another problem cause then I get curious as to how high it will go before it starts to get distorted.:) My Focals and JL amp really sound good. Thanks for the help guys.

[mwiener2]

That's about where I am.. 75x4

A buddy and I got curious and put some ear plugs in and got a dB meter. If I remember correctly, it was around 118dB and 121dB with the car running (running is an extra 2.5 volts)


that's loud for a daily driver stereo