I do not know about this per se, however I have looked this elegant piece of equipment up and down a few times (not in the flesh however)

Minilyzer ML1 - Audio Analyzer

As for price, I guess if you could afford one it might be worth having.

 

Umm, nifty but mine is a 'one-shot' interest so the economics don't work for buying the tools ;-)

 

FWIW, per page 9 of the MS-8 user's manual, you only want to connect Front L/R and Subwoofer signals into the inputs of the MS-8. Do not connect rear, side or center channels into the MS-8.

http://ms8-eu.jbl.com/install.html?file=tl_files/content_resources/jbl-ms8/Owners%20Manual.pdf

You would typically want to use an audio spectrum analyzer, audio real-time analyzer (RTA), or a software tool like Room EQ Wizard (REW) to measure the response of your OEM system, not an O-Scope.

 

.. You would typically want to use an audio spectrum analyzer, audio real-time analyzer (RTA), or a software tool like Room EQ Wizard (REW) to measure the response of your OEM system, not an O-Scope.

x 2, a software based RTA and a calibrated microphone will serve you well, something like this..

TrueRTA Audio Spectrum Analyzer Download Page

or

http://www.roomeqwizard.com/

 

Please read my OP carefully ..... I'm not trying to measure the audible output from speakers/room, I want to know the quality of the high-level signal from the HU alone, not the audible response of the whole system of speakers and amps.

I want to know if it actually delivers a full 20 - 20kHz spectrum to the MS-8 or is it inherently 'limited' in some way. E.g. does Ford filter the signal below a frequency higher than 20Hz because they knew the OEM speakers could not handle those low frequencies (there was no subwoofer in the OEM system)?

 

that's what everybody wants.

I think there are several threads that have random tests on various OEM systems, I would trust that over having to go through the process of it...

I think ErinH did tests on aftermarket decks, using AudioMark or Audio Precision software/hardware?

I would assume that if there's an external amp to the system, it would be as simple as running an RTA on the electrical signal coming from the deck?

it seems like this should be relatively easy information to find out, Bing probably has to do this sort of testing with each OEM system he's told to keep the factory deck...

 

You will have to build a voltage divider, or use a high quality LOC (but the LOC could color your measurement). I've always used a LOC or DSP with OEM sources, so I just run the output of the LOC or DSP (set flat) into the line input on the PC and use TrueRTA, REW or similar to measure freq response. This way I am looking at the actual signal with the OEM HU loaded as I will be using it.

There is a bit more info here:
LINK -> http://www.diymobileaudio.com/forum/how-articles-provided-our-members/73776-using-truerta-mobilepre-measure-frequency-response-headunits.html

 

What Jepalan is saying is that you still need to use an RTA program such as REW, but instead of using a microphone to measure the acoustic response you use the circuit he described to take the electrical output from the source and plug it into the computer.

 

x 2, this Voltage Divider Calculator plus parts labor soldering etc and REW or TrueRTA

or

$43 calibrated microphone, Dayton Audio EMM-6 Electret Measurement Microphone plus cable and REW or TrueRTA

choose your poison..

 

I have the non touch screen HU in my fusion. Played with a AC RTA a few days ago. It's all good.

 

I wonder if you could kinda create a feedback loop of sorts for REW.. Get the OEM signal of one channel down to line-level to feed back into the sound-card as a "mic" maybe. Measure a sweep.. Something like the sound-card calibration does it. Basically bypassing the OEM amp and speaker.. Going direct. I dunno. ??

 

This is an awesome question. I have done this type of testing on my 2011 Ford Mustang GT with Sync. I had a great time doing it & learned a lot. I can share my results with you and the procedure I used. From my experience, Ford does apply equalization to the electrical output on the Sync system.

The testing is pretty straight forward. You just need to disconnect a speaker and insert a resistive load in its place (8 ohm non-inductive resistor would do the trick). You need to hold the load constant so it doesn't vary with output frequency like a speaker does. Then you need to measure the RMS voltage across the resistor while you play sine waves at different frequencies into the resistor. Each time you play a different frequency sine wave, you will record a different RMS voltage and then you can build a simple table with frequency vs. voltage. Then you can plot these in X-Y to see what the frequency response looks like. Ideally you would want to test all the speakers frequency response to see what you have. You can test as many different frequencies as you would like, 15, 30, 60.

A DIY way to do this would be to measure RMS voltage with a o-scope and record the values at each frequency. Another way would be to use a data acquisition tool to do this automatically.

Now, I think a professional way to do this would be using an audio analyzer tool like ones offered by Audio Precision. Unfortunately, these tools cost thousands of dollars if not 10's of thousands of dollars. So DIY method is probably you best bet.

AP High Performance Audio Analyzer & Audio Test Instruments : introtoaudiotest

 

I tested about 60 different frequencies (1/6 octave spacing) at each different volume level (32 volume levels total). And that took about 8 hrs once my test system was set up. Although the results are pretty straight forward, collecting the data and setting this up at that level of detail, is time consuming for sure. I wouldn't expect an average shop to be able to handle this type of testing.

It is totally doable though. And a necessity to understand what your OEM system is doing, IMO.

 

Where did you find 1/6 octave tones? Did you make them?

 

Here is an example of the frequency response (electrical) from my Mustang with Sync. I recall for this test, I used 20k Ohm load.

 

OOH!!, now we can see why factory systems sound funny.

I suspect that other Ford systems have similar responses.

The scary thing is that the response curves become somewhat exaggerated at higher volume settings.

This suggests, with a DeEQ function in a DSP that you need to run the HU in normal use at the volume setting that the system is set up then control the volume through the DSP.

Gerry

 

Why not just swap the head unit and listen for major or even slight differences?

 

I'm just speculating here, but the main reason someone would want to know the FR of an OEM system is so they don't have to swap it out. That's the step that is trying to be avoided.

The second thing to note is that you simply do not have the memory capable of comparing slight differences after the time it would take to swap things back and forth, then level match them. Unless there is a direct, nearly immediate, swap then you will not be able to pick up on any slight differences with any degree of accuracy. Sure, you could probably notice the big differences, but for any useful information to be obtained you would need to level match the two sources, then switch them back and forth to compare them immediately.

 

Yes, ok,

So either doing a setup to quickly swap, or to play one and measure output, play other and measure. I have been able to tell this difference as I played the same track over and over, and i knew it should sound different. so when I did the swap even a minute later, it was obvious. This is years ago, and it was the reason to get rid of the HUnit.

 

Its just shocking to me with people doing this as a profession have no idea about the differences...
at the same time it is so oddly understandable.

A person who builds systems professionally is not always going to be the same guy that's gonna be able to tell the difference from one sound to the other.

If your ear isn't used to hearing sound and then dissecting its character for its nuances, and then measure to test the claims, then its just going to be an unknown.

 

It's shocking to me how much some people over estimate their echoic memory. Yes, a well trained ear can pick up differences that most people cannot, but I think you have a bit too much confidence in your ability to remember sounds that are generally only stored for a few seconds at a time. Our senses are fallible, and we simply cannot recall auditory information after a short period of time. It's reasonable to hear differences, but being able to specifically identify those difference without an immediate, back to back comparison, is not something I would trust. The sources must be level matched, then compared immediately, and even then, saying one is better than the other is challenging without objective measurements. Swapping a head unit and listening over the course of 20 minutes is completely unreliable, and I would not trust and conclusions made from a "test" of this sort.

 

I inquired about this exact subject a few months back and found what is a great solution. The answer came from Bing at simplicity in sound. See the following thread.

http:// http://www.diymobileaudio.com/forum/technical-advanced-car-audio-discussion/168990-testing-factory-frequency-response-per-channel.html

This solution uses your dsp as the voltage divider and REW is a free program. The only difference between this and using REW as an rta is that instead of measuring with a mic, you are measuring the electronicsignature of your channel at the rca level. This is basically a high resolution spectrum analyser using equipment that many serious enthusiasts have already. (Dsp, rew, laptop)

Let me know if you have questions.

This is the factory response of my factory amplified system before I changed to aftermarket.

 

I inquired about this exact subject a few months back and found what is a great solution. The answer came from Bing at simplicity in sound. See the following thread.

http:// http://www.diymobileaudio.com/forum/technical-advanced-car-audio-discussion/168990-testing-factory-frequency-response-per-channel.html

This solution uses your dsp as the voltage divider and REW is a free program. The only difference between this and using REW as an rta is that instead of measuring with a mic, you are measuring the electronicsignature of your channel at the rca level. This is basically a high resolution spectrum analyser using equipment that many serious enthusiasts have already. (Dsp, rew, laptop)

Let me know if you have questions.

This is the factory response of my factory amplified system before I changed to aftermarket.

(Would be nice to see the before vs after graphs)


Thanks for this...While I mostly agree with GiJoe, maybe most people can't, but I don't think most people spend 25 years of their lives listening to music for the sake of sound vs the sake of pleasure as I have. Granted, many of those were just hearing it vs listening to it. Regardless, I too understand an agree with you ..If you let too many seconds pass you will not have a good comparison. So yes, perhaps unplugging a harness and powering back up with the same track maybe fast using 2 sources of the file and making the swap just by the harness...it maybe too long. But if the difference is large enough, I think I would be able to tell...maybe in a 10sec situation? I don't know...So yes, measured is the way to go.

NDN...I have the RF360.3 DSP, and I do have a mic, which I wont use, and makes sense from what I read to testing electronically, vs acoustically.

So how do I go about this? I have REW on a laptop as well. Maybe a video would be the best way to translate this.

Thanks

 

I forgot what the "high level wires" were :-/ (I know)

Everything on my system has been done , apart from changing the head unit.

Surprised, that no one with a recent Toyota, the #1 selling car in America, has tested their system to know if the head unit on a basic system puts out a full range across the volume range?

 

Phil,
I asked Mapletech when he started his Highlander build if there was FR output and as I recall he replied that there was.

 

in response to the FR question mapletech wrote-
"It does...with the caveat that that signal is EQ'd in the HU. When I was doing gain tweaking, I scoped the outputs of the amps, running just sine wave from an ipod app. There is a notable hump around 75Hz, but then a fairly steep rolloff below that. Didn't really look at how flat it was to the lowest frequencies, but those will likely need a decent boost to get 'flat'.
There's some other EQ work done too - I'll put that up once I get to tuning stage - hopefully next week. "

Maybe you can get him out of seclusion to do a followup on his build.



http://www.diymobileaudio.com/forum...m/forum/build-logs-project-install-gallery/167133-2014-highlander-sq-build.html

 

Nice....Yeah, I guess I need a new head unit!
Maybe a 4100nex, or anything better for multi OS (ios&android) compatibility?

I like just about all the tech except for Navigation. Would like camera for not only rear, but another for front....etc


I have a DSP, but it can only do so much when trying to boost certain channels.

 

Here is a way to do it with a volt meter and microsoft Excel. Download the files, put the audio files on a CD, and read the instructions.

https://db.tt/N2kty1TU

https://db.tt/0KPpdvZi

 

Downloaded, quickly read the "Demystifying.." Word document and scanned the ppt presentation ...

Sir, I cannot thank you enough for sharing this incredible toolset and 'tutorial', the spot-on answer to my 'academic curiosity' question with the incredible bonus of explanation in terms that even I can understand.

Printing the tutorial, a more considered re-read, burning the CD, warming-up the RMS Fluke and implementing the procedure will follow shortly I assure you. This is going to be a lot of educational fun (the best kind of fun) without a doubt.

And oh boy, not only the frequency response/EQ aspect but a tool to learn with my ears about how the center channel 'works', something I've struggled to comprehend from written explanations.

Un-ending argument may well likely follow, seems to be the nature of this place. But from me you have nothing but un-ending gratitude for your ability to 'understand the customer' and provide tools and products to 'exceed this customer's needs'.

It's hard for a guy like me to hang around here, so much chaff to sift before finding the occasional grains of wheat. Once again, the wheat has your name attached.

Thank You!

 

One word of caution, every "cheapie" true RMS multimeter (and even a not-so-cheapie one) that I have ever had does NOT measure accurate "true RMS" voltages across the ENTIRE audio bandwidth.

My experience has been that they are accurate up to about 300Hz to 1kHz......OR SO.

something like that.

They (the multimeter marketing/rating/labeling) aren't lying when they say "true RMS", it's just that they also rarely specify a bandwidth across which they remain "true RMS"

EDIT: now that I'm thinking about it, maybe it's like 2kHz..........???

 

A fluke may well work perfectly. It's NOT what I CONSIDER to be a "cheapie" multimeter.

When I say cheapie, I'm talkin like under $100 or less usually.

There are MANY ways to test OEM frequency response.

If a car audio shop hasn't figured out how to do this by now, I should hope that that same shop isn't carrying high end gear like Audiofrog speakers.

Unfortunately, the reality of the scenario is often just that.

 

Being only a 'curious audio enthusiast', freshman level, not an 'industry professional' in any respect whatsoever, Andy's answer to my OP is most welcome. A Fluke 117 happens to be among the tools in my decidedly 'not audio-oriented' toolkit.

While not a 'super-duper pro instrument' it'll still be fun and likely adequate for my purpose and this exercise, which will undoubtedly be more educational and informative for me than simply paying a 'shop' and leaving with a stack of plots.

For me a huge part of the value in the info Andy posted is the 'tutorial' explanation. That being something that audio shops, in my limited experience, are unable (or unwilling) to concisely and effectively communicate to 'less than experienced' enthusiasts such as myself, even if we're among those likely rare customers willing to pay good money for the time to be educated.

You and your shop may well be the exception to my limited experience; certainly my loss that I'm not closer to you and able to enjoy the benefit of your services.

 

There is certainly ALOT of very useful information in there. As is always the case with Andy.

I REALLY hope you werent thinking that I was somehow dismissing Andy's post.

I was merely saying:

What's the reason for using a true RMS meter during this exercise?

Accuracy.

If that's the case, then it should be stated that not all meters rated as being "true RMS" are actually true RMS all the way up to 20kHz.

That's all.

I wasn't "arguing"........or.....saying "no that won't work"......

Nothing like that.

 

As much as I agree that the time you take out the Stock and swap, it maybe harder to tell...BUT, if you are familiar with a specific song/s and know it very well, as you listened to it over and over and enjoyed each second of a voice, or tune...You will have no problem noticing the difference. As a source unit, it should be uncolored and similar if I put a Pioneer vs a Kenwood, no? These 2 may exhibit slight character differences, but not large gaps in difference.

 

Check this out, here is one of my cheapie meters against a 100Mhz scope

(Now, it should be noted that if ABSOLUTE accuracy is what someone is after, scopes don't read absolute voltage levels as well as a good meter. A good scope can be off by a couple percent when it comes to absolute voltage)

Hang on, let me make that pic bigger.......

 

What do you mean by absolute voltage?