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Old 08-01-2014, 01:25 PM   #276
bobditts
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Quote:
Originally Posted by AcquaCow View Post
The man said he used an oscilloscope... is that not self explanatory?

Here, I'll google it for you since you don't know what that means. http://www.decibelcar.com/menuelectro/50-howtocro.html
im the one who used the o-scope genius. Get you names straight before you trying to call someone out :P

But I am seeing now that jesuitson used a calibrated mic and measured the speaker response. So we are talking about 2 totally different types of clipping. Jesuitson, the o-scope measures the signal. with the premium HU, volume level 25 is the max level to which it will send a clean signal to your speakers (or amps/LOC/DSP if you are using a level input off the stock HU). Your measurement is jsut the response from your speakers so your HU is sending a clipped signal to the speakers but that doesnt mean your speakers will clip. Make sense?
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Old 08-01-2014, 08:31 PM   #277
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Old 08-01-2014, 09:02 PM   #278
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Old 08-02-2014, 10:37 AM   #279
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Did you perform your test at 12vdc or 14.4vdc? Volume level 25 is an arbitrary number. What was the output of your amp when performing this test? Maybe my volume 25 is different from your volume 25. Was your source material recorded at 0db? Were you playing single frequency sine waves or broad spectrum pink/white noise? Clipping of the amp will introduce extra harmonics in the drivers when played and it will affect the impulse response time. While measuring a sine wave at 1kHz on axis I recorded no other harmonics in the system. I fail to see what point you are trying to make? Isn't this a discussion on how to make the factory head unit perform better? So you used an oscilloscope and found clipping on your system. That invalidated my frequency response measurements how? What about the post near the beginning of this thread when another person listed the responses given by different EQ settings? Are his measurements now invalid as well? Maybe you should just lead this thread in the direction it needs to go from now on.
I dont think you are understanding the differences I pointed out earlier. I'm trying to help the thread by injecting more education. I'm not arguing what you did at all, but trying to give you more information so it can be improved.

The o-scope measurement is taking at the output of the stock HU (before it ever touches an aftermarket amp or dsp or the stock speakers). The o-scope measures the clipping in the raw signal. The stock premium HU begins to send a clipped signal at volume 26 (25 being the highest non clipped volume). This has nothing to do with the sound from the speakers at this point.

here is a theoretical situation.... For owners wanting to upgrade using the JBL MS8 from the stock HU, you would connect the high level inputs to the tsock HU speaker outputs. The MS8 will then (during the setup) measure the signal coming in to un-eq it and make the signal as balanced as possible. To do this most effectively, you will want to send the best stock signal as possible. This is where the O-scope measurement comes in. If you send the MS8 a clipped signal, it will have a much harder time analyzing it and doing its job. The max volume you would want to use while performing this is 25.

now after you install the ms8 and add your amps and perform the setup, this is where your test with the calibrated mic comes in to RTA the system.

Does that explanation help at all? Hope it isn't confusing.
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Old 08-02-2014, 11:35 AM   #280
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Old 08-02-2014, 11:44 AM   #281
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Old 08-02-2014, 12:14 PM   #282
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I appreciate your "educating me", but it isn't wanted. You didn't answer one of my questions and if you did, it wouldn't really be relevant to this thread anyway. I am not about checking the quality of the factory head unit. I know it sucks... However for people who bypass the factory settings, I measured the spectral response of said system for their benefit. For someone wanting to get the most out of the factory system without tearing it apart and starting a new build, this is the direction I'm going with this. We can start a new thread and discuss slew rates, QE dampening and %THD if you like but not in this thread. If you want to post some measurements for everyone's benefit, then please be my guest... But if you want to argue over my technique in some e-peen battle, I'm through.
Jesuitson, you are being hostile and combative. bobditts has been civil and informative in all his posts on this subject so far. And I can admit that even though he pointed out I wasn't entirely correct on one detail. For all I know, you may have a point and he may be wrong -- this is all getting beyond my technical knowledge -- but you don't have to be a bully about it.

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Old 08-02-2014, 12:32 PM   #283
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Jesuitson, you are being hostile and combative. bobditts has been civil and informative in all his posts on this subject so far. And I can admit that even though he pointed out I wasn't entirely correct on one detail. For all I know, you may have a point and he may be wrong -- this is all getting beyond my technical knowledge -- but you don't have to be a bully about it.
Nicely said night. No idea why Jesuit is being hostile, Bob was simply pointing out that there is a different way to make these measurements.
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Old 08-02-2014, 12:39 PM   #284
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You're right. I apologize. This really isn't a technical forum.
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Old 08-02-2014, 05:19 PM   #285
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hey, bud its all good. More information that is out there the better.
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Old 08-08-2014, 05:58 PM   #286
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Just to clarify something, so by default, if you have a sedan, your EQ settings is equivalent to the "1 + 2 + TUNE (right knob)", and you can switch it to THROUGH MODE by pressing "1 + 4 + TUNE (right knob)".

Now if you want to go back to the default EQ then you just press "1 + 2 + TUNE (right knob)".

Is that right?
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Old 08-08-2014, 11:37 PM   #287
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Just to clarify something, so by default, if you have a sedan, your EQ settings is equivalent to the "1 + 2 + TUNE (right knob)", and you can switch it to THROUGH MODE by pressing "1 + 4 + TUNE (right knob)".

Now if you want to go back to the default EQ then you just press "1 + 2 + TUNE (right knob)".

Is that right?
With the key on radio off yes
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Old 08-09-2014, 12:46 AM   #288
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With the key on radio off yes
Thanks
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Old 08-11-2014, 07:04 AM   #289
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hey, bud its all good. More information that is out there the better.
I agree completely. Weakest link in the chain and all that. Sadly JS decided to delete his posts.

It is good to know where the HU itself works well. Also what is going on with the actual sound being heard.

BTW, Thank You for clarifying the EQ thing. I believe I understand what you were getting at when you said "to a point". Please correct me if I'm wrong:

If the HU is near the point of clipping already, then bumping the EQ, (treble, bass, midrange), could push that into the clipping zone?

In any case, it is nice to know where you are still getting clean sound.

John
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Old 08-11-2014, 09:23 AM   #290
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If the HU is near the point of clipping already, then bumping the EQ, (treble, bass, midrange), could push that into the clipping zone?
Thank you! I was wondering the same thing, but wasn't quite sure how to phrase it clearly and succinctly. Especially if it's true that effectively increasing volume by turning up B/M/T together isn't quite the same, acoustically-electrically, as simply turning up the volume. Which was at the root of my previous question.

Eager to hear any clarification (no pun intended) on this point.
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Old 08-11-2014, 09:39 AM   #291
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correct. This is why it is preferred to cut, rather than to boost.
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Old 08-11-2014, 09:52 AM   #292
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correct. This is why it is preferred to cut, rather than to boost.
If you're already up past the clipping threshold ... say, I often have my volume in the 30 range ... does cut vs. boost still matter?

That's assuming if I cut EQ, I might turn up the volume slightly to compensate, and if I boosted EQ, I might turn the volume down slightly.

Is it a wash in that case, or is one way better than the other? I'm wondering if the electrical capability of the built-in amp is taxed differently by boosting volume vs. by boosting EQ.

I realize each approach would result in somewhat different frequency characteristics (thinking back to the chart way earlier in this thread that graphed the effect that boosting B, M, and T each had on the shape of the curve), so if it's the same either way as far as quality goes, it might be up to personal preference.
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Old 08-11-2014, 09:56 AM   #293
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If you're already up past the clipping threshold ... say, I often have my volume in the 30 range ... does cut vs. boost still matter?

That's assuming if I cut EQ, I might turn up the volume slightly to compensate, and if I boosted EQ, I might turn the volume down slightly.

Is it a wash in that case, or is one way better than the other? I'm wondering if the electrical capability of the built-in amp is taxed differently by boosting volume vs. by boosting EQ.

I realize each approach would result in somewhat different frequency characteristics (thinking back to the chart way earlier in this thread that graphed the effect that boosting B, M, and T each had on the shape of the curve), so if it's the same either way as far as quality goes, it might be up to personal preference.
this is where user control comes in. You have to know the limits of your system. If you want more, you need to upgrade. Think of it as a performance mod. You need to know the limits and when to stop pushing the current gear.

If you cut frequencies in the EQ and then turn the volume up louder, you are likely to cause damage quicker. Also, the HU will only boost a certain voltage. Once you meet that voltage, you cant boost more. Cutting will allow you to minimize the use of your EQ voltage.
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Old 08-11-2014, 10:13 AM   #294
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this is where user control comes in. You have to know the limits of your system. If you want more, you need to upgrade. Think of it as a performance mod. You need to know the limits and when to stop pushing the current gear.

If you cut frequencies in the EQ and then turn the volume up louder, you are likely to cause damage quicker. Also, the HU will only boost a certain voltage. Once you meet that voltage, you cant boost more. Cutting will allow you to minimize the use of your EQ voltage.
So I'm still not clear on which approach is better, because it sounds like you've given a reason each way, unless I'm confused.

I'm not pushing my system hard enough to break anything, so at worst, sound quality suffers. I like my music loud, but not that loud. Plus I have the OEM Kicker sub, and its crossover greatly limits the bass that reaches the cabin speakers, so they're not taking nearly as much abuse as they might be otherwise.

So are you saying if I'm not cranking it up enough to damage anything, cutting EQ while boosting volume slightly is better than the opposite? In terms of sound quality.
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Old 08-11-2014, 10:18 AM   #295
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you dont tweak the EQ just to get more volume out of your system. You set the volume to your listening level and tune the EQ there.
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Old 08-11-2014, 10:27 AM   #296
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So I'm still not clear on which approach is better, because it sounds like you've given a reason each way, unless I'm confused.

I'm not pushing my system hard enough to break anything, so at worst, sound quality suffers. I like my music loud, but not that loud. Plus I have the OEM Kicker sub, and its crossover greatly limits the bass that reaches the cabin speakers, so they're not taking nearly as much abuse as they might be otherwise.

So are you saying if I'm not cranking it up enough to damage anything, cutting EQ while boosting volume slightly is better than the opposite? In terms of sound quality.
If your end game is louder, then quality speakers and a quality amp will get you that.

As bob stated, EQ is not to make your radio louder. It is simply to fine tune your system to get the best sound quality possible and to match your own personal tastes.

If you having trouble fully understanding it, try adjusting the EQ on your radio. Adjust each one separately, once you hear the difference, it may be easier for you to understand it.
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Old 08-11-2014, 10:54 AM   #297
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If your end game is louder, then quality speakers and a quality amp will get you that.

As bob stated, EQ is not to make your radio louder. It is simply to fine tune your system to get the best sound quality possible and to match your own personal tastes.

If you having trouble fully understanding it, try adjusting the EQ on your radio. Adjust each one separately, once you hear the difference, it may be easier for you to understand it.
I am well aware of what the EQ is for, thank you. If you read back through some of the more recent posts in this thread, you'll see that what we we've been talking about is (in part) the difference between boosting EQ at one volume vs. cutting EQ at a slightly higher volume, yielding the same effective volume level either way.

For instance, I could create a typical "rock EQ" curve by running B+5, M 0, T+3, or by running B 0, M-5, T-2. The relative differences between the values are the same in both cases, and the frequency curve would be about the same shape, but I'd have to turn up the volume a notch or two to get the same effective volume in the second case.

And my question to bobditts was, which way would yield better sound quality given the performance characteristics of the sound system as he's measured them: boosting EQ at a slightly lower volume, or cutting EQ at a slightly higher volume.

I'm also well aware that I could get better quality at higher volumes with upgraded amp + speakers. That's not what this thread is about. It's about getting the best possible results from the stock system, and my question pertains directly to that goal.
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Old 08-11-2014, 10:58 AM   #298
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And my question to bobditts was, which way would yield better sound quality given the performance characteristics of the sound system as he's measured them: boosting EQ at a slightly lower volume, or cutting EQ at a slightly higher volume.
provided you could get the same results, it wouldnt matter. however, starting with a signal that is already clipping is not going to yield the same results. Boosting a signal at the lower volume could cause the signal to clip.
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Old 08-21-2014, 04:58 PM   #299
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Excellent news -- Through Mode is indeed flat in both the front and rear channels!

I did some initial testing with a CZ624U1, using a makeshift line-out converter. Here is a frequency response comparison between the Sedan and Through Mode settings:



With loudness turned off, the response stays the same regardless of volume level.

Through Mode is flat to within 1 dB from 40 Hz to 20 KHz. The actual low-end response is slightly better than what's shown here; the capacitor in my LOC was on the small side, which caused some extra rolloff.

Looks like Sedan gives the fronts a +3 dB boost at 80 Hz, and a -7 dB cut at 250 Hz. The rears have a -9 dB slope from 1 KHz down to 125 Hz, then a quick rolloff below that.

Results for Wagon mode were identical to Sedan, so they are not shown here. (I'm guessing that both settings are there to be consistent with what they've done for other models, even though there are no differences in this case. The DSP chip in this unit can actually be programmed to do time alignment, dynamics compression, etc., but it seems highly unlikely they'd use them.)

Note that you will have quite a bit more bass going to the rears in Through Mode, so you may want to make sure you're not overdriving them, and fade more to the front if necessary.


As for the loudness function, here's what happens at various volume levels when it is enabled:



With the volume set to 12, there is an 11 dB boost to the low bass, and an 8 dB boost to the high treble. The boost decreases as you turn it up, until it is flat by a volume setting of 35. The decrease is slow until you turn it pretty far up, where it falls off more rapidly. This explains why at medium volumes it has so much "boom and sizzle."


The loudness and fixed EQ are both rather heavy-handed, but it's really the combination of the two that makes it so awful. Hopefully these results will be helpful when deciding what adjustments to make.
THANK YOU VERY MUCH FOR THIS.

I'm an EE and I really appreciate this.
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Old 08-21-2014, 08:03 PM   #300
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To help a bit more with system tuning, I measured the effects of the bass/midrange/treble controls. It uses the typical frequencies of 100 Hz / 1 KHz / 10 KHz, with a +-12 dB range, as shown here:




One interesting quirk is that the change is not constant throughout the 0-8 range:



Lower settings are closer together, which is actually pretty nice. A lot of decks go in 2 dB steps, and I often wish that I could make a smaller change.

Another thing to note is that boosted frequencies are limited above a volume setting of 34. For example, at a volume of 35, moving the bass from +7 to +8 makes no difference. At 40, there is no boosting at all. Cuts still apply, though.
and big thanks for this too. This confirms what my ears were hearing.
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