Measuring Audio Quality?

[jbailer]

Can anyone point me to instructions on how to measure audio performance? I want to keep my system as stock as possible, just want to replace the speakers in my 201a Shaker Pro system. If it really fails miserably, I might consider a very light upgrade of amp/sub if it is VERY easily reversed for sale.

Looking around, I found an app called RTA Audio (free) for my iPad. It seems like it's probably a good tool but I'm really not sure what to do with it or what to look for. I mean all I can think of is replace speakers a pair at a time and then look to see if the frequency levels are higher at the same output level but I have to believe there's something more I should do? Any help or ideas would be greatly appreciated. I know nothing about this stuff.

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[jasonstang]

You can't measure audio quality. Everyone has different hearing.

 

[jbailer]

You can't measure audio quality. Everyone has different hearing.

OK, like I said, I'm a noob at this so please be patient, maybe I used the wrong wording. How about audio performance? I'm thinking I should be able to use the app to measure if my speakers actually improved the audio or not. I guess quality I would hav eto be measuring signal to noise or something.

 

[jasonstang]

OK, like I said, I'm a noob at this so please be patient, maybe I used the wrong wording. How about audio performance? I'm thinking I should be able to use the app to measure if my speakers actually improved the audio or not. I guess quality I would hav eto be measuring signal to noise or something.

You can by doing a frequency sweep to see if the new speakers improve frequency response.

 

[lowatts]

I mean all I can think of is replace speakers a pair at a time and then look to see if the frequency levels are higher at the same output level but I have to believe there's something more I should do? Any help or ideas would be greatly appreciated. I know nothing about this stuff.

It sounds like you'd get more useful information by asking about how others with your Shaker system did with their upgrades. That way you can see what kind of results others are getting for the type of upgrades they are putting in, and what was involved in putting in the upgrades (to judge how reversible it is). You've probably already searched other threads on S550 Shaker system upgrades, that's a good place to start.

 

[jbailer]

It sounds like you'd get more useful information by asking about how others with your Shaker system did with their upgrades. That way you can see what kind of results others are getting for the type of upgrades they are putting in, and what was involved in putting in the upgrades (to judge how reversible it is). You've probably already searched other threads on S550 Shaker system upgrades, that's a good place to start.

Thanks, I have actually looked at what many others have done. It seems it is mostly just replacing speakers or a massive gutting of the stock system. I want to go with replacing the speakers but at the same time, I want a way to quantify the improvement. If you don't measure it, then it is only subjective. One person says it sounds great while the next person say it is missing punch or highs or whatever. I just thought someone knew a good way to actually measure the real gains. I guess I'll just mess around with it and the app I found.

 

[MrBoogie]

Technically the frequency spectrum should be as close to flat as possible. It's usually measured with a RTA using a pink noise signal. Actual RTA's have very sensitive microphones, which I doubt a phone app can match. The mic is also setup on a stand at ear level in the drivers seat for the measurement. That said, everyone has different hearing. Back when I had competition SQ car systems, I'd use different equalizer settings for scored competition and every day listening. To my ears a flat response didn't sound great, but it scored well. The Shaker system leaves a lot to be desired, so any changes would likely be an improvement.

 

[jbailer]

Technically the frequency spectrum should be as close to flat as possible. It's usually measured with a RTA using a pink noise signal. Actual RTA's have very sensitive microphones, which I doubt a phone app can match. The mic is also setup on a stand at ear level in the drivers seat for the measurement. That said, everyone has different hearing. Back when I had competition SQ car systems, I'd use different equalizer settings for scored competition and every day listening. To my ears a flat response didn't sound great, but it scored well. The Shaker system leaves a lot to be desired, so any changes would likely be an improvement.

That's great info thanks! This "pink" noise generator, can I just download an MP3 somewhere and play it through the stereo? I've never heard of this. Even if I'm not trying to set it up for competition, it sounds like that would be a good consistent pure source to use and then measure the output changes using the app I found. May not be professional quality but it will still measure a difference. Thanks again!

 

[MrBoogie]

No problem. Yes, you can download an MP3 and play it through the stereo. Pink noise is literally noise with equal energy at all octaves. It sounds like static.

 

[lowatts]

Thanks, I have actually looked at what many others have done. It seems it is mostly just replacing speakers or a massive gutting of the stock system. I want to go with replacing the speakers but at the same time, I want a way to quantify the improvement. If you don't measure it, then it is only subjective. One person says it sounds great while the next person say it is missing punch or highs or whatever. I just thought someone knew a good way to actually measure the real gains. I guess I'll just mess around with it and the app I found.

I know what you're saying but I think you will find just measuring frequency response won't get you the information your looking for. What I did, just to mess around, is when I got my V6 last year I installed the "Audio Tool" app to my Android phone from Playstore. I put sound files--not sure where I got them from anymore--on my SD card to play back from the Mustang's USB music player. Each file plays a particular frequency. So when I play each file I can use the Audio Tool app to measure the loudness of each frequency step. I set my Bass, Midrange, and Treble controls to try to get the response curve level and it did help some with that. I actually got the curve to be reasonably level (from about 80 Hz to 9KHz since I can't hear above 9K anymore), surprisingly. And I'm mostly happy with this.

But here's the thing... this is the standard 2016 Mustang audio system and most people on the forum will say it sucks, yet it actually has a pretty flat (by in-car standards) response curve now. I would add that the response curve will vary by loudness level to a degree--I set mine to be as flat as possible when it's loud since that's how I like to listen. Having said all this, most people could've gotten the same results just by playing around with the level controls and listening for what sounds good to them. And most of all for your purpose, the curve I got was about what I'd seen for high-end system if I recall correctly, yet obviously this is not a high end system and does not sound as good as a high end system. It goes back to the limitations of trying to quantify audio reproduction quality by measuring only a system's frequency response--frequency response being only a small part of the total experience.

 

[wildcatgoal]

Join DIYMobileAudio.com and ask this question. There, I and others with actual car audio experience can help. Plus you'll find the answer you need there without asking. You need a quality mic, software, and uncompressed pink noise to measure audio response.

 

[mumbles]

Join DIYMobileAudio.com and ask this question. There, I and others with actual car audio experience can help. Plus you'll find the answer you need there without asking. You need a quality mic, software, and uncompressed pink noise to measure audio response.

This ^^^
Lots of great info on that site!

 

[fifteen5oh]

You need to play a given feq 60Hz, 75Hz, 125Hz ect. and use a device at the end of the signal to see if you are getting the feq playing and only that feq.

There are a few devices that you can use, most are real expensive and will take you awhile to learn how to use, OR there is a device , SMD DD (Distortion Detector) I have one and used it many times.

You play the provided CD select a track, and connect the leads to the output lines (rca or speaker out puts) and say you are playing the 40Hz track look for the 40Hz light to come on and be steady, if as you turn up the volume and get distortion it will tell you because the device is looking for only that certain Feq and distortion will introduce other Feq.

Look it up it can be a help full tool for setting gains on an amp (if you don't know how to by a DIMM) and your stereo volume knob level before clipping/distorting.

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