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voyagerx 02-24-2013 02:04 AM

Factory Frequency Response
 
3 Attachment(s)
I finally started my install tonight and while I was in the drivers doors, I decide to check the factory frequency response for the woofer and tweeter. I will be using a 3Sixty.3 to auto normalize the factory EQ, but it only normalizes it at one volume. If the factory Amp has volume dependent EQ, then you have to compromise by accepting it, or leaving the headunit volume on one volume, and using the 3Sixty.3's remote volume knob. The good thing is, it doesn't look like there is too much volume dependent EQ work being done on the front woofer and tweeter. I haven't tested the other speakers yet, but will get around to it as i progress - I am curious about the sub.

To do the testing, I had a SNI-35 laying around and used Room EQ Wizard. I did not calibrate the db/volts of the SNI-35, so the db scale is not accurate in the images, but it is at least relative and will give you an idea of what the factory tune is. I also have not verified that the SNI-35 has a perfectly flat response from 20Hz-20kHz - it claims to.

Here is the front left woofer with the volumes at 5, 15, 20, and 25.

Attachment 20136

Here is the tweeter at 5, 15, 20, and 25

Attachment 20137

Here are the two together at volume 15. I will caveat this with a few things. The stock woofer is 2 ohms, the stock tweeter is 4.8 ohms. I have no idea what the stock amp delivers power wise to these two at their respective impedance's. This is with both using whatever the impedance of the SNI-35 is (I didn't measure).

Attachment 20138


Not sure if this helps anyone, but figured I would share. Please let me know if you have any questions.

For reference, these are 1/12 Octave with 1/12 smoothing

voyagerx 02-24-2013 02:24 AM

Re: Factory Frequency Response
 
3 Attachment(s)
In case anyone cares, here are a few screen shots with using the factory EQ.


Woofer at volume 15 with the Mid at -9, 0, +9

Attachment 20139


Tweeter at volume 15 with the Treb at -9, 0, +9

Attachment 20141


Woofer at volume 15 with the Bass at -9, 0

Attachment 20140

1stJeepGC 02-24-2013 07:45 AM

Re: Factory Frequency Response
 
Greetings,

Great Post, very informative.

Any chance if you get the data on the sub?

Best for now.:)

voyagerx 02-24-2013 12:56 PM

Re: Factory Frequency Response
 
2 Attachment(s)
Got around to working on the sub this morning. The good news is, it doesn't look like it does any volume dependent EQ on it either.

Sub at volume 5, 15, 20, 25

Attachment 20151


Sub at volume 15, with Bass at -9, 0, +9

Attachment 20152

1stJeepGC 02-24-2013 01:46 PM

Re: Factory Frequency Response
 
Quote:

Originally Posted by voyagerx (Post 766731)
Got around to working on the sub this morning. The good news is, it doesn't look like it does any volume dependent EQ on it either.

Sub at volume 5, 15, 20, 25

Attachment 20151


Sub at volume 15, with Bass at -9, 0, +9

Attachment 20152

Greetings,

Thank you for your research.

I agree with your conclusions, it seems that the DSP is concentrating on the steering logic for surround sound and time delay. Keeping the sound as flat and natural as possible. Hooking up the 3.sixty.3 (or any processor) to the factory amp will give you the ability to fine tune the sound to your liking.
If you are using your center channel speaker, I would just plug into the processor directly and play with it from their. This way you can establish your midrange balance for the vocals & etc.

One last question, out of curiosity, were you able to zero in with the actual factory crossover points with your software. I was looking for sub and front woofer points.

Best for now.:)

voyagerx 02-24-2013 03:17 PM

Re: Factory Frequency Response
 
1 Attachment(s)
Yes, I wass planning on running the center and just using it directly as is through the 3Sixty.3. I was going plot that as well. I wanted to play a bit more to see if I can figure out what it is doing for the center channel, and if it screws with the left and right channels either. I also was going to see if I could try and determine factory time delay (if any) with some impulses, but I haven't looked in to it enough.

Wonder if the Center is just R-L so everything true left and right doesn't end up at center or if something else is going on. I'll play with center when I get a chance and use left and right channel source outputs to see what effect it has on center.


I can't actually tell the crossover point, and can only take a guess since there seems to be some factory EQ at the points I would guess, making it not be a perfect slope.

If I had to guess, I would say the Tweeter is a 5kHz HPF with 6db slope with some factory EQ between 2-4kHz - though I noticed the factory tweeter also has a cap on it, so I'm not sure if that is doing more.


The door woofer seems to be band passed between 33Hz and the higher end is a little harder to tell. Somewhere between 500Hz and 2kHz it starts to roll off, but with the factory EQ, I wouldn't want to try and guess anything more specific. It also appears to be a 6db. It seem to be a fairly low crossover point for the low pass side (500-2khz), and a fairly low point for the high pass side (34Hz).

Guessing that they counted on the tweeter and woofer summing to fill in the gaps. There would almost need to be some time delay for this to have any chance of working.

Also guessing they have the door woofers playing so low to make up for the sub.


It's interesting that the sub seems to have a very high peak around 28Hz, and almost immediately rolls off.


Here are all three on the same chart

Attachment 20159

1stJeepGC 02-24-2013 04:28 PM

Re: Factory Frequency Response
 
Quote:

Originally Posted by voyagerx (Post 766829)
Wonder if the Center is just R-L so everything true left and right doesn't end up at center or if something else is going on. I'll play with center when I get a chance and use left and right channel source outputs to see what effect it has on center.


The door woofer seems to be band passed between 33Hz and the higher end is a little harder to tell. Somewhere between 500Hz and 2kHz it starts to roll off, but with the factory EQ, I wouldn't want to try and guess anything more specific. It also appears to be a 6db. It seem to be a fairly low crossover point for the low pass side (500-2khz), and a fairly low point for the high pass side (34Hz).

Guessing that they counted on the tweeter and woofer summing to fill in the gaps. There would almost need to be some time delay for this to have any chance of working.

Also guessing they have the door woofers playing so low to make up for the sub.


It's interesting that the sub seems to have a very high peak around 28Hz, and almost immediately rolls off.


Greetings,

Again, excellent work on your part to take your time and provide the analysis to the WK2 community.

Basically, the center channel is coming from a 2 channel source within the DSP's internal input/output mixer (no user access). The sound engineer programing the Eurphony will take any were from 40-60 percent of the L-R signal and assigned it to the center. Then the next step of course is the steering logic, delay, eq and any crossover points to blend in the front stage.

The Arc Audio PS-8 processor in the advanced mode allows you to create your own surround sound environment. With the 3.sixty.3 you can adjust to your liking except for the blend and the steering logic. My feeling is that the blend of the center is perfect for the JGC, 50 or less thus allowing the windshield to spread the sound image.

The combination of the sub and front woofer, according to your findings is what I expected. It looks like Chrysler gave Alpine a stupid specification and in order to make it work, Alpine had to go this route. The cap on the tweeter may be their to control the midrange frequencies and to prevent it from overloading.

I am now wondering if the full range rear door is designed more for the midrange punch that is laking up front instead of a traditional side channel in a 7.1 system.

Are you going to sum the sub, front woofer and tweeter? That is going to be my plan if I keep the factory amp in the loop. The center and the rear pillar will be going direct into the processor. The rear door will stay on the factory amp's dsp then routed into the aftermarket amp.

Keep the data flowing and best for now.:)

voyagerx 02-24-2013 05:43 PM

Re: Factory Frequency Response
 
After seeing these results, I will most likely be summing the tweeter, door woofer, and maybe sub. I wasn't expecting the sub channel to roll off at such a low frequency - if it played level up to 80Hz, I would have just used it without adding it to the summing mix. Anyone using just the factory sub channel without some major EQ work would be missing quite a bit of the low end frequencies. If they don't have the EQ power to do it or a processor to sum all of the channels, the front door woofer seems to be a better channel to grab from. At least it is much flatter to 30Hz.


The one thing I have always been curious about with summing is the negative consequences of factory time alignment. If the front tweeter , woofer, and sub all have different time alignment - I wonder what this does do the audio when summed. Technically I know what it does - it just sums all of the audio as it arrives, but I wonder how much this screws with the sounds since everything will be out of alignment. Obviously the greater the delay between channels when summing, the more effect on the way it sounds. I know the 3Sixty.3 can add time alignment, but this is on the output side after already summed, not the input side.

If the factory timing messes up summing, I may not even include the sub when summing, as it will be much further out of alignment than the front tweeter and woofer (which will have more delay).


The front woofer frequency playing down to 30Hz and with some EQ work between 20-30Hz, will be plenty for the 10 inch sub. I can then delay the sub output with the 3Sixty.

1stJeepGC 02-24-2013 06:39 PM

Re: Factory Frequency Response
 
Greetings,

I always recommend to sum the sub, front woofer and tweeter in a factory system that uses a surround system. They always play with something and in order to get that fresh signal, thus, the summing.

After I sum, each of those 5 signals are going into their own input in order to get them processed for the new output. I will lose the 7.1 after the sum which will then become a 7.0. In music, this really does not matter that much. And with the delay on the sub, I can adjust the the effect and bring in back into alignment to suite my taste.

Once again, thank your for your efforts and keep us post with the results.

Best for now.:)

subbie09 02-24-2013 09:24 PM

Keep up the good work.

voyagerx 02-26-2013 06:14 PM

Re: Factory Frequency Response
 
2 Attachment(s)
I measured the center today.

Center at volume 15 with top line being both channels played (full stereo sound), bottom line being only 1 channel played. So... even at full left or right, a good portion of audio is still going to center.

Attachment 20234



Since the door woofer is also two ohms, I included it in this one since output to the same resistance should be relative (neglecting speaker sensitivity differences between the two)

Attachment 20235

1stJeepGC 02-26-2013 08:06 PM

Re: Factory Frequency Response
 
Quote:

Originally Posted by voyagerx (Post 768389)
I measured the center today.


Since the door woofer is also two ohms, I included it in this one since output to the same resistance should be relative (neglecting speaker sensitivity differences between the two)

Greetings,

Was this the front door?

Best for now.:)


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