Out of my mind?

[ttocs]

wow, can't believe I am the one that is nuts now. The iphone mic might be consistant, but it is also a far far cry from the audiophile quality that a true RTA's mic needs to be to calibrate anything with it. If i go throw my iphone on the dash and then call you while listening to music will you be able to tell me what freqs needs adjustment? While you might have got it from an expert, and it might have been made by some very smart people the fact that the hardware that is measuring it sub-standard for what it needs to be again makes it nothing more then a neat toy.

I use to fly rc airplanes and there was a guy that downloaded an app that used the doppler effect to find out how fast something went as it went by you. We also had another member that had a fairly nice radar gun that they used for his kids pitching. When we put the two next to each other and measured the same plane the closest we EVER got the two to read was 15 mph difference, and that was when it worked. Now in a plane that is only doing 30 mph to read 15 mph off is a significant difference. I am not sure how it comes up with a graph with freqs that it is not good at recieving such as bass, it probably just makes it up honestly...

[Eric D]

A microphone need not be "audiophile quality" depending on what you are trying to accomplish.

If you take a random full range speaker (any one), and then measure its frequency response with a $50,000 lab grade microphone, you will get a response curve.

Now take a $1 microphone used with a laptop and some $100 software, and measure the same speaker under the same conditions.

When done, compute the difference between the two curves and then use this result as a compensation curve for the cheap $1 microphone.

From this point on you can use that $1 microphone to do your testing, and it should be within a few db of that $50,000 one used first.

In the case of the iPhone mic, what matters most is that every iPhone mic off the assembly line is similar enough. So long as they are within a few db you should be fine. Even the Behringer $50 lab mic uses at $0.25 element which is mass produced.

This is just mathematics, not smoke and mirrors.

Tom brings up a great point though, the iPhone mic is not omnidirectional. It is optimized for the person speaking into it. Ideally you would want an omnidirectional mic instead.

However, the iPhone with its cheap mic is still useful for finding where things are at, and where they need to go. I am not going to pull in the lane at an IASCA competition, bust out my iPhone and claim I have an award winning setup. I would however trust that iPhone and its app to do a better job of letting me know what needs to be done with the system than my ears.

Ears are only good for relative measurements. You cannot quantify anything with your ears.

Relative examples: "This stereo sounds louder than that one" "My tweeters seem to bright" "The bass in this system sounds boomy"

Quantifiable examples: "There is a hole in the system response of 6 db located at 1kHz" "Your subwoofers are out of phase with your components" "I need to decrease the gain on my component amplifier by 2db to better match with my subwoofer amplifier"

[ttocs]

strange that artists often spend so much on nice microphones since they could do just as well with their iphone? You will never convince me that the iphone min and an audiophile quality one will show a similar result, to me thats like toms monitor analogy earlier. Sure it will get a curve, might even look similar(doubtfull honestly) but to say that a couple of db's here or there are not important is crazy. If you are that concerned about the quality to look at a couple db's difference and throw them away as not important doesn't make any sence. The only thing I agree with you on is that you will not convince any judge, competitor or anyone that knows what sounds good that your iphone has made your system perfect.

but back to the point I was trying to make earlier. It is possible to tune eq's, even large ones by ear and get what you would consider to be sound good from them. Takes a little time yes, no you will probably not win any competitions with it either but I am willing to bet you would be happier with going by ear then you would by what your rta says since we agree that flat sound generally isn't enjoyable. So again if you are not competing I do not see the need to run an rta on the system unless you are going through the judging lanes.

That is unless you are using the rta to find a different shaped graph that I am not aware of? Is there one other then flat that you try to get it shaped like?

[dwnrodeo]

That is unless you are using the rta to find a different shaped graph that I am not aware of? Is there one other then flat that you try to get it shaped like?

I believe their goal is not a ruler flat response (with the exception of Eric as he mentioned earlier) it's to use the RTA to find peaks and dips in the frequency and adjust as necessary. This will iron out any major "kinks" and allow you to fine tune the lows and highs to your personal desires (using your ears). Using an RTA to smooth out the frequency response is like using an oscilloscope to set your gains, and I know you own an O-Scope. Sure you could just hear when the music is clipping, but wouldn't you rather be sure with a scope? It just makes things a little easier for people such as myself who don't have golden ears.

[ttocs]

ok then if you can't hear these differences that the rta can see, what does it matter if you are not having a judge look at them? If you are the final judge of your system, an rta is useless............

[Eric D]

There are plenty of reasons why an artist would spend money on a good microphone. Having a flat frequency response is probably not one of them. A good microphone will survive a fall or 4ft or more and still work just fine. A good microphone would be omnidirectional so they don't have to hold it one specific direction to speak into it. Many good microphones are now wireless.

Walking around on stage talking into an iPhone does not make any sense.

But what do you consider as a good microphone? The Behringer ECM8000 is a $50 lab mic. It consists of a $1 or less electret element in a durable aluminum case.

http://en.wikipedia.org/wiki/Electret_microphone

To make any accurate lab measurements with it, you need a compensation curve for it. Now take a better mic, say an Earthworks M50 ($1,300). Even this excellent lab mic has a compensation curve available...

http://www.earthworksaudio.com/electron ... ion-files/

The M50 is rated at +1, -3db frequency response. With the compensation curve you should be able to significantly improve that.

The critical aspect of any microphone be it cheap or expensive is consistency. When you buy a $0.25 elecret element on its own, so long as it is mass produced with some level of consistency, you can create a compensation curve (transfer function if you will), and make accurate measurements with it.

The different shaped graph to shoot for is any graph which is smooth. Look at the attached graph I put on this post. That response could use some work.



It is lacking low frequency bass. There are holes at the following frequencies, 100Hz, 630Hz, 3.15kHz, and 16kHz. All those areas could use a little boost. Then, there are spikes at the following frequencies, 63Hz, 200Hz, 1.6kHz, and 6.3kHz. These could use a little cutting. If you make these adjustments the system will not be flat at all. It will have a gradual curve from the low frequency region on down to the high frequency region. Without a RTA, very few people would be able to find those bad areas and improve them.

My home stereo is pretty much ruler flat (down to maybe 60 or 80Hz, then it rolls off, as I don't use a sub). It is easily in the top ten best stereos I have ever heard, and all the people I have ever had listen too it have agreed. I have managed to get my car stereo flat or very close to it on a few occasions. The results were awful. Lifeless dull rubbish. So, now I go for a smooth response instead and things are far better. Part of the problem with car audio is you have a totally different system dependent on if you are sitting in a parking lot, or if you are moving down the road. While moving most systems need more bass response to sound balanced over all the low frequency road noise.

[Eric D]

ok then if you can't hear these differences that the rta can see, what does it matter if you are not having a judge look at them? If you are the final judge of your system, an rta is useless............

If you think a RTA is useless, then why stop there? DMMs are useless, o-scopes are useless, tape measures are useless, levels, scales, lasers, and any measuring instrument in between are all useless.

You can tell if something is level just by looking at it, right? And you can guess the length of something within a fraction of an inch too, right? You can probably guess the voltage of something with your tongue, or on bigger stuff just grab one hand on each wire and estimate the voltage from the shock you get...

I guess all you need for good car audio is a screwdriver, set of allen wrenches, hack saw, chisel, and a big ass hammer...

[ttocs]

ok then if you can't hear these differences that the rta can see, what does it matter if you are not having a judge look at them? If you are the final judge of your system, an rta is useless............

If you think a RTA is useless, then why stop there? DMMs are useless, o-scopes are useless, tape measures are useless, levels, scales, lasers, and any measuring instrument in between are all useless.

You can tell if something is level just by looking at it, right? And you can guess the length of something within a fraction of an inch too, right? You can probably guess the voltage of something with your tongue, or on bigger stuff just grab one hand on each wire and estimate the voltage from the shock you get...

I guess all you need for good car audio is a screwdriver, set of allen wrenches, hack saw, chisel, and a big ass hammer...

knowing if something is level, or that measurements of length are not important is a really big jump, but ok we can address that. Having something level is normally necessary just to ensure that everything will either stay on the shelf or that every measurement after that is correct. Compairing that to an rta on a car audio system that will never be in competition is an apples an oranges comparison to me. There is a time and place to have measurements down to the micron and there is a time when +/-1/4" isn't really important. It is important in semeconductor manf to have tools calibrated down to microns but no it will not do you any better to use the $1000 level we had in the fab to make your shelf in you bedroom "more level" then your $20 home depot one would. I am all for using the right tool for the job, but again if the RTA doesn't make it sound any better what are you buying by using it? I can see using a scope to max your gain but will still argue(just like any other industry professional I have met so far) that a meter is a horrible tool to tune a system with.

I hope I am upsetting you as that is not my point. This all started because someone said you can tune a 1/3 octave by ear which is wrong. Just like running an rta on your system will not guarantee you to win any competitions, neither will tuning by ear. I can promise anyone here that if they spent some time, listened to their system(god forbid that happens!) and tune as they go that it can be a much more enjoyable exp then an rta and can leave you just as happy with the sounds. I am not so sure why EVERYONE on here seems to be afraid to either listen to their system or afraid to trust their ears but until you start doing these things, an RTA will in no way help you. An rta cannot tell you, me, or anyone else what sounds good to them again because the taste of the listener is subj to what they like. If we ran around throwing RTA's in everyones stereos and told them what they had done was wrong, infinity would never sell another coax. Those damn things make my ears bleed with the tweets on them but people still love them.

[smgreen20]

I'm sorry, but most people can't trust their ears. Our ears are so easily thought, that if not thought right the first time around that you have what we've got here, a feud about sound reproduction.

To prove how easy we can train/trick our ears ,go out to your system and change a few frequencies and listen to it like that for a few weeks. Then change it back. It will sound off to you.

So even if you don't know how it's to sound an rta is valid outside the competetion lanes.

[stipud]

knowing if something is level, or that measurements of length are not important is a really big jump, but ok we can address that. Having something level is normally necessary just to ensure that everything will either stay on the shelf or that every measurement after that is correct. Compairing that to an rta on a car audio system that will never be in competition is an apples an oranges comparison to me. There is a time and place to have measurements down to the micron and there is a time when +/-1/4" isn't really important. It is important in semeconductor manf to have tools calibrated down to microns but no it will not do you any better to use the $1000 level we had in the fab to make your shelf in you bedroom "more level" then your $20 home depot one would. I am all for using the right tool for the job, but again if the RTA doesn't make it sound any better what are you buying by using it? I can see using a scope to max your gain but will still argue(just like any other industry professional I have met so far) that a meter is a horrible tool to tune a system with.

I hope I am upsetting you as that is not my point. This all started because someone said you can tune a 1/3 octave by ear which is wrong. Just like running an rta on your system will not guarantee you to win any competitions, neither will tuning by ear. I can promise anyone here that if they spent some time, listened to their system(god forbid that happens!) and tune as they go that it can be a much more enjoyable exp then an rta and can leave you just as happy with the sounds. I am not so sure why EVERYONE on here seems to be afraid to either listen to their system or afraid to trust their ears but until you start doing these things, an RTA will in no way help you. An rta cannot tell you, me, or anyone else what sounds good to them again because the taste of the listener is subj to what they like. If we ran around throwing RTA's in everyones stereos and told them what they had done was wrong, infinity would never sell another coax. Those damn things make my ears bleed with the tweets on them but people still love them.

Why do you even have a nice stereo at all, if you don't care about tuning it? This is an audiophile forum. We don't talk about what is "good enough", we talk about how to get the best out of our systems, period. What you are saying is along the lines of putting a $5000 into upgraded car parts, and then never tuning it on a dyno. Well if Billy Bob can tune your carbs by the smell of the exhaust, why would you ever need to use a dyno? Herp derp. If you want to get every last drop out of your stereo, especially when you're messing with a 1/3 octave EQ (tuning one is not unlike a standalone ECU), you don't use your ears. Quantifiable measurements and an understanding of how to use them is what the fun and interest behind car audio is all about. If you're not into that, why spend your life on car forums?

[Eric D]

I want my system to sound the best that it can. If I install my system, tune it by ear and it sounds good, fine so be it. But what if I put an RTA in it, made adjustments to smooth things up and then listened too it? What if once I did this I found the system to sound better than it did before?

Does it make any sense to not get the maximum potential out of something?

Most good EQs have the ability to defeat their settings. A great test is to put two of them in series. Set one by ear, and then set the other with an RTA. So long as you know what you are doing with the RTA you will choose the one set with the RTA over the one you set by ear. I am NOT claiming the one set with the RTA must be set flat. Just smooth up what you have to begin with. It will be a big improvement.

[Eric D]

Also, I should add that I am not upset by this argument. I think it is a very good argument to have, and others may learn from it.

I just find it funny you don't wish to use any test equipment for anything car audio related. How do you think the manufacturers ended up creating the products you use? Do you think they built an amp and just listened to it and said the frequency response sounded good enough to sell? What about speakers? Someone designs a speaker, never uses any test equipment, just plays it and says it sounds great, so now let's sell it.

Audio without test equipment is a scary thing...

[kg1961]

I am really enjoying this thread.
Im like ttocs never used a rta. I would like to just never had the chance.
If i kept a car and stereo that long.
My wife made a good point last night and this is what staring me posting al the items for sale. I feel i know what i like for sound and it has taken a long time to find what i want. but i feal most of the reason i change is i have not spent the time to set it up with a rta or a eq.
the best setup i had was in my 68 bettle but i did have 2 30 band audio control eq and my friend was a installer and tuned it for me
i still messed with it a bit till i loved it and i have been changing that set up ever since

[ttocs]

correct this what I would consider to be an audiophile forum and to turn that around on you, if we are audiophiles here why do we not trust our ears and are what part of us would be considered in the"most people do not know how to trust their ears" statement made above? If the RTA is made to make small adjustments that your ears can't distinguish, that is entirely different then when I HAD to put my mustang on a dyno to tune it. The 94-95 mustangs prior to obd2 systems are notorious for their computers not liking aftermarket heads/cam and the computer taking timing out to try and figure out what is wrong. Replacing the EE-chip and completely reprogramming the system in the cars computer to recognize the new parts and work with them so that they will run is not the same. Most newer cars will require tuning to run with big aftermarket parts but ask how many DIY carborated drag racers have put their cars on a dyno for anything less then to find a number and you will be suprised.

We already had one member on here come on and say that after another member ran an RTA on their system that they were not happy with the outcome. This has nothing to do with the user of the RTA, this has generally been my experience with people that do run an RTA. Competition vehicles if they use the old slider eqs will do their car the day before the competition because they make adjustments to it inbetween so it sounds good to them. Just because we are techno fans and audiophiles doesnt' mean that you will necessarily benifit from an RTA. Sure its a neat tool that we all would like to play with but to act as though it IS the tool that will fix everything, no sorry. Are you telling me that after you run the rta you do not make any final adjustments to suit what sounds good to you and you leave it as-is? If you are I think you are missing the point of have a nice stereo if you are afraid to trust you ears and make the adjustments to what sounds good to you, the final and most important judge of your stereo....

[Eric D]

Step 1: Install stereo
Step 2: Set gains on all equipment for no clipping, and max signal to noise with oscilloscope
Step 3: Smooth system response with RTA
Step 4: Relocate speakers if response from RTA is too far off (then go back to step 3)
Step 5: Listen to system and make minor adjustments (by ear)
Step 6: Readjust gains with oscilloscope if any boost was added at EQ (use boosted EQ bands as signals) (this step is to eliminate clipping at the boosted EQ points)
Step 7: Enjoy better sounding system with more headroom and signal to noise than the guy who did all this by ear...

Adjusting car stereos by ear is what high school kids do in their driveways. Anyone serious or professional about car audio understands the value of an RTA and an oscilloscope to get the job done quicker and more accurately.

[ttocs]

this just sounds like alot for the average DIYer installer that just wants to enjoy good audiophile quality. Oscope maybe I can see but re-adjusting speakers? How often has anyone on here done that after an RTA? And if it is all followed by "Make minor adjustments by ear" then I see no problem with doing it all by ear. Those are all perfectly good steps for anyone that has plans to compete but again its just overkill and not necessary if your ears are the final judge.

with 99% of the forum still saying a volt-meter is a good way to adj gains I find it humorous that now the same crowd seems to think an RTA is just necessary for good sound.

[Eric D]

Last I knew, speaker placement was 75% or more of good sound. I was taught that back when I was an installer, I have read it in many car audio publications, and I dealt with it all the time when I worked for a major car audio speaker manufacturer.

If you throw some components in your factory locations, you may get lucky and they will sound good. Most of the time though, putting them in kick panels, or even just sealing up the back side by putting them in some pods of some sort drastically improves sound quality.

The great part about an RTA is you can actually measure all the improvements made by doing these things.

Besides that, how do you know if anything improved from one major installation change to the next? At best humans can only tell a difference in an A-B comparison with a minimal delay in time between the two options. If you had speakers in your doors, then built some kick panels, just how much better (or worse) did the system become? If it did get worse, you may think it got better simply from the psychological aspect of the work you put into it, and your own justification for that work. With the RTA, you can put a QUANTITY on the measurement, and know right away if things are better or worse.

You make it sound like this test equipment is out of reach for most people. Today you can get o-scope apps for computers, cheap hardware versions of them as well, and software RTAs are within reach. If one is willing to spend $1,000 on an amp, they might as well spend a few hundred on some test equipment to get that amp performing at its max.

When I first bought some test equipment, I spent $1,200 or so on my RTA. At that time the most expensive amp I owned was $550. But, I knew I could use that RTA for a long time with a lot of systems (not just my own), so it made sense to me. All told I probably have $5,000 in test equipment now, and every so often I keep adding to the collection.

[ttocs]

So - your point is that an RTA is now a must-have for any DIYer audiophile to get better sound no matter if its a iphone or a behringer since a mic is a mic is a mic and and RTA always makes things better(except for above reference with tom)? I think we are forgetting that while we all call ourselfs audiophiles that there is still a large number of members that support tuning gains with a meter(I think I am still the only one aginst it). To go from that to an RTA is a big jump for most poeple here that would be better off spending the time sitting in the car listening to it.

If you do not trust your ears to make the initial adjustments, why do you after the rta?

[stipud]

So - your point is that an RTA is now a must-have for any DIYer audiophile to get better sound no matter if its a iphone or a behringer since a mic is a mic is a mic and and RTA always makes things better(except for above reference with tom)? I think we are forgetting that while we all call ourselfs audiophiles that there is still a large number of members that support tuning gains with a meter(I think I am still the only one aginst it). To go from that to an RTA is a big jump for most poeple here that would be better off spending the time sitting in the car listening to it.

If you do not trust your ears to make the initial adjustments, why do you after the rta?

[Eric D]

When I am done tuning MY OWN system with an RTA, I leave it alone. I don't make any adjustments by ear, because for me personally that just makes it sound worse.

I think the vast majority of people want to make some adjustments by ear, so they can get it good with the RTA first, then go ahead and change it too their preference.

The best bet for the personal tweaker types is to use a chassis mount EQ to get their system perfect (as close as they can), and then use a dash mount EQ with a few bands to "play with" the sound of it as they choose.

This argument is really no different than the Epicenter, BassCUBE argument. A lot of people like these things so they can crank up the bass on songs they wish to. I personally am the "set it and forget it" kind of guy. Once my system is adjusted, the only time I adjust it again is if I replace something or redo the whole system.

I am not advocating everyone has to run out and get an RTA. What I am really advocating is the point that you need an RTA to set a 1/3 octave EQ. If you don't use an RTA to tune one of these EQs, you will never get it right. Take it a step further to modern digital EQs with parametric EQs and using an RTA becomes an absolute necessity. There is no way to tell where you are at and what you are really adjusting on a parametric without one.

[ttocs]

well I disagree just simply because if you and your buddies are going to be the only ones in the car, there is no reason you can't do it by ear and be happy in the end. Maybe one day you will find an rta and throw it in there to see what happens, but that does not mean that suddenly at that point what you have done before was wrong..... Maybe it will improve the sound, maybe it will not as we have heard both cases but at no point will the rta tell you that what you did was wrong. It can tell you a different way to do it but again with the way some people love infinity, and the way that you like your sound flat, everything inbetween is still acceptable to someone and will make them happy. UNTIL the day you sit a judge in your car there really isn't anyone that can tell you that your stereo is set up wrong, and no need for an rta.

I draw the line that an RTA is necessary at the point someone wants to compete, you say its as soon as a 1/3 octave or parametric eq is purchased. To each his own...

[Eric D]

Maybe this whole argument boils down to skill, and you simply have much more skill than I do.

The first EQ I purchased was a Rockford Fosgate OEQ2. This is a 10 band stereo parametric EQ. Once installed I spent countless hours trying to get it to sound right. At least a few weekends were wasted in vain as my final result was garbage. I ended up just using the EQ defeat button to run the system with no EQ, as it sounded a heck of a lot better. I finally managed to convince my boss to let me borrow the shop's AudioControl RTA for the weekend. I spent one Saturday with the RTA and dialed the OEQ2 in to the point the system sounded way better than without an EQ.

Then a few years down the road I got my hands on a Rockford Fosgate Symmetry EPX2. Same problem, no matter what I did it sounded like crap. This time the EPX2's variable crossovers were also added into the mix of things to tweak. By this point I had a new employer with even better toys. I borrowed a Linear-X pcRTA which has 4 microphones in an array. After another weekend, the EPX2 was sounding good. At this point I was sold on RTAs, so I bought my own. Now I can take as much time as I want to squeeze every last ounce of performance from my setup.

I have owned (and used in my vehicle) the following EQs...

RF OEQ2
RF Symmetry EPX2
AudioControl EQL
AudioControl EQT
AudioControl DQX
PG EQ215
PG EQ215ix
PG EQ232

I own the following RTAs...

AudioControl SA3050
Linear-X RTAjr
TrueRTA setup with USB preamp, and Behringer mic
iPhone with RTA app

I also own a Linear-X LMS swept sine wave analyzer

I love EQs, and I think they are one of the most beneficial products for car audio. I know for a fact that I personally cannot successfully set an EQ by ear. I tried with no luck on multiple occasions and have given up. I now let test equipment be my ears, and the results have brought me an audio experience which has been nothing but joy.

If you can set your EQ by ear, you are far more talented than I. More power too you!

[kg1961]

..

[smgreen20]

Whatever the case may be, my purpose of wanting an EQ is to smooth out and set a slightly downhill flat response. We seem to fail at seeing your point, but the same goes that you fail to see our point.


Sound is subjective to a point. We all agree on that. But my point behind all of this is that if you don't know what to listen for, you will need an RTA. Now that I'm off for the next 11 days, I will be teaching my ears and self, "how to hear".

Here's the link I stated earlier.
http://harmanhowtolisten.blogspot.com/2 ... isten.html

[Eric D]

Eric want to lead me one? i will pay shipping both ways?

An EQ, or an RTA?