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Discussion Starter · #1 ·
Hello Mazda 6 fans...

I understand there have been some questions regarding the frequency response of the base audio system and whether the CleanSweep is necessary in the 6. We just finished testing a 6 with base audio system (2003 model) and I thought I would share the data with you guys.

Connections were made right at the OEM head unit's outputs for all four channels. All Channels are full-range. The CleanSweep was calibrated at OEM volume setting "25".

Here is the left front channel:


The red curve (thin line) is the OEM response (all tone controls flat). The thick blue curve is the CleanSweep corrected response. Other than a mild high-frequency roll-off, the factory response of the front channels is reasonably flat (a lot better than most new cars).

Here is the left rear channel:


Again, red is OEM and blue is corrected with CleanSweep. The rear response is not very nice at all without correction. If you want your rear speakers to play only midrange it may be fine... otherwise you probably don't want to use these signals without a CleanSweep.

Based on the above, for those looking to stay within a budget, you can get decent performance using the front outputs with a simple LOC or straight into an aftermarket amp with compatible inputs as long as you're willing to accept some volume dependent effects...

At low volumes (OEM vol "10") there is a fairly aggressive loudness compensation curve that rears its head:



Here, the red curve is the raw OEM response at Volume "10", the blue curve is the response with a CleanSweep calibrated at Vol "25" with the OEM volume set at "10". If you left the OEM volume at 25 and used the CleanSweep's volume, the corrected curve would remain flat (see blue curve in the 1st graph). Again, this is probably not the end of the world if you're on a budget but if you want a totally linear volume/freq.response relationship, the CleanSweep will deliver that.

Now, at high volumes (OEM vol "32") there is some mild low freq. attenuation. Not terribly objectionable (compared to most new cars).


So, in a nutshell...

The front signals are quite usable, the rears are pretty nasty.
There is volume-dependent EQ shifting, but it's not that horrible in the 6.

For the budget minded who don't need an Aux input, a CleanSweep is not necessary. A good amplifier with differential-balanced inputs can take the front outputs of the head unit directly. Some amps will require LOC's.

For the audiophile who wants a linear volume control and a clean, line-level Aux input the CleanSweep makes sense.

I have not measured a 6 with the Bose system yet. If I do, I will post data.

Hope that answers some questions.

Manville Smith
JL Audio, Inc.
 

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hmm so is this out yet? and how much is the MSRP?
 

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Manville,

From my own testing, obviously I don't have the equiptment that you do, but my RTA showed the front and rear inputs of the bose amps as ruler flat. The mixed subwoofer amplifer output and the speaker outputs where a much different story.

I look forward to your test results of the system



For everyone not familair with Msmith, he is the VP of marketing of JL audio, the makers of the clean sweep.
 

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Originally posted by t_mo_t@Jul 11 2005, 03:33 PM
hmm so is this out yet? and how much is the MSRP?
[snapback]452887[/snapback]​

Yes it is.

www.jlaudo.com

It is $350-$400, I can't recall exactly.
 

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Kick ass info right there. You have to love when a person who works for a company trying to sell a product gives you such objective information. Great work, and thanks a ton!

btw, this needs to be stickied right now
 

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Discussion Starter · #8 ·
It wouldn't surprise me if the Bose Radio outputs (Bose amp inputs) are flat... many of the newer Bose systems (those that are not bus-controlled) have usable signals that don't require a CleanSweep.

Any So.Florida Mazda 6 w/Bose owners who would like to volunteer for a conclusive test?

Best regards,

Manville Smith
JL Audio, Inc.
 

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Originally posted by msmith@Jul 11 2005, 05:03 PM
It wouldn't surprise me if the Bose Radio outputs (Bose amp inputs) are flat... many of the newer Bose systems (those that are not bus-controlled) have usable signals that don't require a CleanSweep.

Any So.Florida Mazda 6 w/Bose owners who would like to volunteer for a conclusive test?

Best regards,

Manville Smith
JL Audio, Inc.
[snapback]452977[/snapback]​

Thanks manville, I was the one who asked you to test this on carsound. Turns out I fixed the problem and it was a leaky box and some clipping. After building a new box and attenuating tweeters, system sounds amazing running off front speakers and a LC6. You the man.
 

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Wow Manville! You do still get around. :) This guy has been helping the industry for ages! His knowledge, info, and help has been top notch for many many years! Just had to put out another thanks for the help, and brutal honesty, EVEN if he doesnt get a sale out of it(see his post about using the front output and LOC).

:)
 

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Discussion Starter · #11 ·
Originally posted by JrV@Jul 11 2005, 08:30 PM
Wow Manville! You do still get around.  :)  This guy has been helping the industry for ages! His knowledge, info, and help has been top notch for many many years! Just had to put out another thanks for the help, and brutal honesty, EVEN if he doesnt get a sale out of it(see his post about using the front output and LOC).

:)
[snapback]453095[/snapback]​
You're welcome... Our desire is to make aftermarket audio possible in all these new cars. If you don't need a CleanSweep, that's fine with us... you can put those dollars into better speakers or amplifiers (hopefully JL, of course). There are many cars where CleanSweep makes a dramatic difference and can be the key to getting good audio performance... the base 6 is simply not one of them. The CleanSweep will clean up the response in the 6 by a little bit and provide a cleaner signal and an aux in, but as I stated in my first post is not absolutely necessary for most users. If you're looking for audiophile-grade performance it would be a worthwhile addition.

Best regards,

Manville Smith
JL Audio, Inc.
 

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Hi. Thanks for the test results.

It is reasuring to know that the factory output is quite linear.

I have mine connected through a LOC and tbh it doesn't sound too bad (Non Bose).

What I am wondering though is at what level does the factory head unit begin to clip.

Assuming all levels are flat and the ALC thing is off, do you have any figures on the levels before clipping etc.

I am trying to avoid buying a scope just to set it up properly once, although I fear I may have to ;)

Cheers,
Adam.
 

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Discussion Starter · #13 ·
There is a pretty simple way to audibly test for clipping... get (or burn) a CD with a 1 kHz sine wave tone (recorded at 0dBfs, full level) and play it through your system. Gradually raise the volume until you hear the tone change and gain higher frequency content... that's the clipping point. No scope needed.

Best regards,

Manville Smith
JL Audio, Inc.
 

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Originally posted by msmith@Jul 15 2005, 04:34 PM
There is a pretty simple way to audibly test for clipping... get (or burn) a CD with a 1 kHz sine wave tone (recorded at 0dBfs, full level) and play it through your system. Gradually raise the volume until you hear the tone change and gain higher frequency content... that's the clipping point.  No scope needed.

Best regards,

Manville Smith
JL Audio, Inc.
[snapback]457072[/snapback]​
wow, thanks for the very quick response.

Fron your info, could I say set the amp at a low gain and use this to test for clipping in the head unit amp via the LOC, and once the theoretical maximum is found on the head unit, use this to set the gain on the amps themselves thus gaining the maximum out of the full system !

Does it work like this...

Cheers,
Adam.
 

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Discussion Starter · #15 ·
Originally posted by Twonks@Jul 15 2005, 01:13 PM
wow, thanks for the very quick response.

Fron your info, could I say set the amp at a low gain and use this to test for clipping in the head unit amp via the LOC, and once the theoretical maximum is found on the head unit, use this to set the gain on the amps themselves thus gaining the maximum out of the full system !

Does it work like this...

Cheers,
Adam.
[snapback]457139[/snapback]​
Keep in mind that if you set your amp up not to clip at all you will likely be disappointed with the output. We can tolerate clipping of peaks pretty well. Use the sine wave to establish your head unit's clipping point. Then reduce the volume to about 75% of that level... then follow the gain setting guidelines in our gain setting tutorial at jl audio.com.
 

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Originally posted by 1st MP3 in NH@Jul 11 2005, 09:40 PM
Yes it is.

www.jlaudo.com

It is $350-$400, I can't recall exactly.
[snapback]452893[/snapback]​
I thougt i'd seen it for 180$ ??

Would this kit also filter out the damm noise that my mp3 module is generating?
 

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Originally posted by msmith@Jul 11 2005, 08:16 PM
Here is the left rear channel:


Again, red is OEM and blue is corrected with CleanSweep. The rear response is not very nice at all without correction. If you want your rear speakers to play only midrange it may be fine... otherwise you probably don't want to use these signals without a CleanSweep.

Manville Smith
JL Audio, Inc.
[snapback]452803[/snapback]​
Waaaaaw, that explains why those rear speakers sound so bad.
I was looking to buy some better speakers then the originals, but the problem is located in the amp curve.

@Manville,

How did you measure this freq. response? Did you use a CD with white/pink noise and an calibrated microphone on your Audio Precision?
 

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Manville,

I want to replace my factory 8" subwoofer in the read deck with an 8IB4 but I cant find one anymore. Any thoughts or suggestions?

I do have the Bose system but that will not pose an issue for integration.

Eric
 

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sparky, I was told by a guy at Tweeter that they can still get them (8IB4), don't know how true this is, but i'd try there if you really want one.
 
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