Clean Sweep LINK

I just read this and thought it might have some cool potential for aftermarket installers. It's mostly geared towards non-DIN-sized "irreplaceable" OEM HU's that are pre-equalized to cure OEM evils and shortcomings. Basically you can't replace your HU because nothing else will fit, and if you replace your speakers or amp it will still sound like crap because the OEM HU has embedded, irreversible equalization parameters.

"A particularly difficult challenge was dealing with the reality that a huge number of OEM head units now incorporate non-defeatable equalization curves aimed at correcting the response of factory speakers, as well as protecting relatively weak factory speaker systems from overload. Examples of these include bass roll-off at increasing volume settings, or severe midrange EQ to tame the response of OEM speakers."

This could relate to the S2K in the sense that the dash controls were previously unusable with new HU's (before our co-S2Kers worked out a few aftermarket solutions.) In that sense, to maintain full functionality the OEM HU was "irreplaceable."


This "CleanSweep" has you put in a calibration CD, press "calibrate" and it sets parameters to covert the frequency response for its outputs to FLAT, regardless of what is coming in from the HU. It does this completely digitally by converting whatever levels your outputs are at to a digital signal, equalizing it, then outputting to your amp(s).

So the question is, can it be made to do MORE? Does it do more than correct the one problem of pre-equalization?

-Will it clean up the HU signal and have it provide greater S/N ratio from its outputs? (How, I don't know...is there any circuitry that can make a bad HU signal into a clean one?) It outputs at 8V, so that gives a theoretically higher signal to your amp(s), but is the noise correspondingly high?

-Most people don't want a FLAT signal going to their amps. They want to correct for deficiencies in their amps and speakers, and may want to avoid resonances characteristic of their specific vehicles. Will JL allow users to play with this instrument's entire spectrum of equalization? Seems like a waste if they don't. Maybe you could burn a false calibration CD and have it anti-correct to your desired profile?

Anyway, it seems like a cool toy and it should be out in May.

 

i think its a crock of shit. im not exactly quite sure what its about, but a quick glance at the companies recent profile shows they like to bs a lot. the only that performs well from JL is the W7. everything is overpriced and definately not worth buying, obviosly IMO.

what doesnt make sense to me is that it digitally resets everything flat? so basically, it goes from digital -> analog -> digital -> analog? i hope it has at least a 24bit DAC.

 

I just don't see any use for it. Why would I take substandard sound from a substandard OEM head and try to equalize it? In the end, it's just a flat-response substandard signal.

Plus, by the time you spend the money to buy this thing, why not replace the head to begin with? Seriously... if you're someone who feels the need to flatten the equalization just so you can tweak it to your liking with some other high end equipment, why on Earth would you stick with an OEM head in the first place?

I just can't see any useful applications where the money wouldn't truly be better spent elsewhere.

Oh, and they claim an "effective" 24-bit resolution. That's marketing speak for randomly dithering the lower couple of bits to increase the S/N ratio. In the end, though, all that does is prevent lowering the stock head's crappy S/N ratio even more.

 

Since I still have my stock HU, I was kind of interested in this piece, especially if the user (me) has some control over what it does. Then I heard the MSRP would be around $400. That should get me a pretty nice aftermarket head unit.

This product seems aimed at more expensive cars than the S2000, cars with head units that have even more function integration than just dash controls (integrated navigation, for example).

By the way, does anyone know if the S2000 stock head unit uses equalization to compensate for the awful stock speakers? Has anyone ever run an RTA or microphone test to measure this? A big part of JL's pitch for the CleanSweep is that car makers use all kinds of DSP tricks to make bad stock speakers sound better. This was news to me but not surprising.

 

Dunno if that piece works well, but look at the dash on a TL- or my wife's TSX- and there ain't a good way to replace the stock deck, especially if you have nav. Sure, it might be dumb in an S2000- with an easily replaceable DIN deck.

JL is a pretty solid company. I don't know what that thing costs but if it helps integrate a virtually unreplaceable OEM deck with aftermarket amplifiers it might be worth it.

 

[QUOTE=MacGyver,Jan 19 2005, 06:34 PM]Plus, by the time you spend the money to buy this thing, why not replace the head to begin with?

 

it's interesting you found this -- i also saw this a few days ago and it struck me as a good idea for people trapped into the OEM systems.

i'm not sure, but i do know this much... i was playing/experimenting w/ the wife's stereo in the Odyssey the other day after reading JL's release info.... i found that whenever i turn up the volume, the bass VERY audibly drops off in proportion to the rest of the signal as the volume gets higher... even if i turned the bass up to max, as i increased volume, it virtually vanished. so, clearly Honda is playing this game... now, are they doing the same in the S2000? dunno, but i wouldn't be surprised now...

 

Yes it does! As I have pointed out before in older threads, the stock headunit utilizes a built-in equalizer that you cannot defeat. Play the stock speakers straight from a power sources without an EQ on it and you'll notice it'll sound nasty. Honda purposely wanted to tweak the setting so that it would make up for the lack of sound quality. I am willing to bet that most people (not just s2k owners) have at least their treble up a bit because the perception with the treble increase is having more precise sound and crispier notes. Tuning the headunit with an undefeatable DSP is cheaper than replacing the speakers with much more expensive speakers in 10,000+ cars.


Some people prefer the looks of the stock deck and may not like the more flasier headunits that are available today. I prefer a simple looking deck over most aftermarket decks. I have alpine headunits but I am ready to take them out since they are screaming with lights. Not my style. I would have kept the stock deck of mine, but my stock deck is a tape player and I need something that plays CD


THe purpose of the JL audio cleansweep is to flatten the response as much as possible so you can tune it with an EQ without having to raise or lower the boost too much. You will start out with a fresh flat signal and tuning would be much more pleasant than dealing with the stock headunit's skewed signal.


To some, they are worth it, to others, they aren't.

 

There's nothing this unit can do that a good EQ can't do (at least from what I garnered in my quick look a couple of days ago). Besides, once you flatten out the signal, you'll most likely want to tune it with an EQ to get the signal shape you wanted. Might as well skip the Clean Sweep, adjust the EQ to your liking, and call it quits (not to mention saving $400 in the process). At least the EQ gives me the option of doing something other than flat.

 

Starting with flat frequency response is a good idea, just hard to do. So this device sounds valuable from the perspective that it does it automatically without extra tools or taking it to a high-end shop and paying $200 for them to EQ it manually. If it really compensates for high-volume bass roll-off it must be a pretty smart unit, and that would of course require that you adjust the factory volume control through it's full range during the setup procedure so it can learn your HU's roll-off curve.

I assume this thing has a remote mic so you can position it where your head is? (OK no comments on where your head is).

But I agree that without allowing customization it's kind of expensive. For $450 you could buy a pair of Audio Control 30-band EQ's and have it both ways.

BTW - don't forget about "loudness contours" which cause bass and some treble to roll-off at higher volumes. Nearly all volume/tone chips used in radios these days have this built in. If done correctly, the roll-off matches the ear's sensitivity curve so it sounds like the bass stays the same as you adjust volume. But if implemented "wrong" it can be used to roll-off bass output at higher volumes.

It may not be fancy DSP built into the factory HU, just a simple analog volume-control chip with the "loudness" function tweaked.