That's a good source of info, been using it for a decade or more.

 

Thanks! I figured that some, if not many, of the forum members may have ran across this guide at some point. I just wanted to share and help some people who are going through the learning curves...Like myself LOL

 

Good information, but remember a couple of things.

1. The boosting / cutting mentioned relates to recording / reproducing music in a far field environment, with limited impact of reflections. Reproducing the same sound in a near field hostile environment, riddled with reflections / cancellations will mean, that you first need to cut everything and then think of boosting. Once you have a flattish FR then think of boosting 3.15khz a bit from -3 to -2 db.

2. While the chart gives cues to what happens at each frequency, don't under estimate the role of harmonics on the overall sound. How you set 200hz will affect 400hz like 3khz will affect 6khz and so on.

 

Great tool.
Thanks for posting.
I finally understand the meaning of transparency now.

sqnut
Thanks also for the head's up about the cascading effect from the adjustments.


Bret
PPI-ART COLLECTOR

 

Thank you for posting this!

 

Thanks, Now I have to go out and play with my stereo for another full days straight.

What music do you listen to to balance the system? What music has the best recording?

 

I'd start with the focal cd, the one with technical tracks or something like Meca Chesky disc. I believe each league has its own ref cd, anyone of these would do fine.

Think of tuning in two steps. The first is getting the foundation / base set this is about getting the measurements right. Then going back and re-calibrating things, as you fine tune, this is about getting it to sound right.

Getting a ref sound will help a lot. At the end of the day it's about how it sounds not how it measures. At least in a car. Getting a ref sound is also the first step in, 'learning to listen', 'tell the difference' and hence identify 'better or worse' with some degree of accuracy. Listening to some competition cars or even a good 2ch home setup is a good reference point.

Hear the sound for things like tonality, stage dimension, the level of focus in the imaging etc. Listen with your eyes closed. If you set your ref with a home 2 ch then know that the 'size' of the stage will have to be scaled down for your car, without any loss of impact, imaging clarity tonality etc. I didn't have an option when I started off, but if you can then do visit some of the sq shows.

As a first step, work on getting your drivers in phase. With your deck, enter the measured distance of each driver, that's a good point to start. Now play with the delay between the mids etc. If you're active, cut the tweets and sub and play with the delay between the mids. On the focal disk there are some tracks for polarity test. The same track is payed in and out of phase. If you have your speakers in phase, the track played in phase should focus up in front and when played out of phase, should focus up at your speakers. Getting your speakers in mechanical phase is step 1. Getting them in acoustic phase is step 2.

Next, work on balancing the FR for left and right side. The disks have test tones at 1/3 oct intervals, like your eq. Use a spl meter or an rta app on your phone and run the tones one side at a time. Note the difference between L/R response at each frequency and correct for that. Correct by cutting both sides. Keep in mind that above 1 khz the tones are highly prone to reflections, so if you can get LR response within, say 1.5-2.5 db, that's fine. Next, level match across the 10 octaves playing all drivers and get all 31 frequencies within say 2-3 dbs. Now listen to music.

Chances are it will sound muted and muffled. NOW go back to your ref sound and see whats missing, then check the charts to see what you need to boost or cut. While doing this you may set L/R 0.5-1db differently from what you set earlier, that's fine. As long as it helps with tonality without any negative impact on the other parameters. This is level 2.

If you have your phase dialed in but L/R FR is out, you will see and feel the sound smeared across your stage. You will not be able to pin point the location of each component, vocalist, drums, guitars etc.

The third variable you control is the cross over points and slopes. I would do the above keeping these parameters fixed. I would start with a xover point within the 3-4khz range and steep (24db) slopes. The sub/mid cutt off at 50-60hz again on steep slopes. Getting the sound dialed in is a labour of love. It takes a while.

Stage 1 is about setting one thing at a time and stage 2 is about using all three variables together.

Hope this helps.

Arun.

 

MrMoto,

Check out the Alan Parson's Test CD. There are band-limited noise tracks, which you can listen to, and find out which frequency you need to tame/bring up. It is easy and much better than RTA, as you hear the rattling sounds too, which RTA could mix with higher bands.

There is some phasing tracks too - for woofers, midrange and tweeters - you can check/fix your phasing issues with these tracks. They offer the reverse phase too, so you shouldn't swap the + and - everytime just to check which one is better.

Sine waves help you find the source of distortion in your system. They should sound as clean as possible. Anything that don't sound clean - have some degree of distortion. You can play with gains/levels/car plastics just to find the source of distortion, and then fix it. Otherwise you'll need some pricey measurement rig, which could do THD figures.


The sine sweep helps you find out short on FR (but deep) dips, which could be the issue of relative phase between mids and tweeters. If they are deep, and take place in the xover range - be shure you have the wrong phase polarity.

 

Great info. Thanks for posting.

 

Good sound is almost always well balanced. Good balance does not equal flat rta. A flat FR is a starting point. Balance is when your left and right stage are one entity One side isn't brighter then the other and both sides weigh in the same.

Balance is when the transition from a 20hz note to a 400 hz note is seamless. Just like the transition between 2-8khz and beyond. So yes there will be others who have the sub x'd at 100hz where the presentation will hinge on sub response, vs a balanced setup where the sub hits when it should.

Signs of imbalance: Your stage is heavier on one side, your stage is focused right but one side is brighter, your stage pulls towards one side Stuff that you should solve with ta or L/R eq.

If you listen to a good 2ch or a good comp grade car,this balance should be fairly obvious.

Arun

 

Nice guide, definitely helpful

 

This is the kind of thread that gets me frustrated and has me pulling out my hair (and I have precious little left). Why? Because nowhere in it does anyone address the most essential and fundamental factor in being able to properly tune/EQ a sound system for the most accurate playback of music, and the basic assumption made is that the ability to mechanically manipulate the sound is all that is needed.

The EQ resource posted by Bluenote is a good resource. However, I find this guide to be an even more helpful resource: http://recordingwebsite.com/articles/eqprimer.php. And, here is another I have found quite useful: http://www.reverse-engineering.info/Audio/bwl_eq_info.pdf. However, as SQNut has properly noted, the guidelines given (in the resource provided by Bluenote and the ones I have provided) relate to EQing during the recording session. I also agree with SQNut, for the reasons he has noted, that you cannot necessarily translate the boosting and cutting suggestions offered in these EQ primers into what you will be able to realize upon playback. I must also add that the results on playback will also vary greatly because during the recording session the sound engineer is able to exercise much greater control over how each instrument or voice is recorded, and thus how it sounds (or is supposed to sound) on playback. Whereas, on playback (unless you are listening to a recording of a solo voice or instrument), any adjustment you, the listener, makes at a particular frequency will affect everything already recorded at that frequency and its harmonics. Thus, it is a recipe for disaster, in my view, to treat these guidelines as guarantees for perfect sound in the music listening environment.

You cannot simply cut and boost certain frequencies and expect results that approach accurate reproduction of music without properly RTA’ing your car to determine what kind of frequency response you are actually getting prior to EQing and, in my view, more importantly, without having at least some understanding of the sound characteristics of various musical instruments and your favorite vocal artists and the music frequencies they cover. Thus, another necessary resource is one of the many 1/3 octave frequency charts available that show which instruments cover the audible frequency range in music playback. Here is an excellent chart: Interactive Frequency Chart - Independent Recording Network. After looking at a chart such as this you might be shocked to see how much fundamental and harmonic frequency overlap there is among a variety of instruments.

Mr. Moto asked “What music do you listen to to balance the system? What music has the best recording?” SQNut responed with a “tuning” tutorial and suggests listening to a “good 2 ch or a good comp grade car,” and S3T offers additional “tuning” advice. Rather than quibble with or debate the tuning methods and thought processes they suggest, I will point out that ANY tuning advice is useless unless you have first listened extensively to live (preferably unamplified) music and have as a reference the sound of real instruments and voices. In my opinion, one cannot profess to be able to “tune” a system or know what “good sound” is, or whether a particular vehicle’s playback system can serve as a reference, without first knowing the differences in sound between a cornet, a trumpet or a flugelhorn, or a bassoon and an oboe, or a cello and a double bass played with a bow, for example. Can one profess to be able to properly “tune” a system without knowing what distinguishes the sound Miles Davis creates from his trumpet compared to say Freddie Hubbard or Chet Baker, or what Diana Krall, Elvis Costello or any other popular singer sounds like in person? I say no because the objective of this hobby of ours is to recreate as best as possible in your listening environment the live music experience, and having the aural capability of identifying the tonal qualities of a particular instrument or voice is, to me, absolutely critical to successfully accomplishing this task.

And then there are the recordings on which we rely to tune our systems. The live music experience I discuss above is necessary if you are going to be able to determine whether a particular recording is true to what that particular musician or singer sounds like. Sure, based on my experience as a musician, the number of live performances I have attended, and being a critical listener of recorded music, I can point you to recordings that I believe successfully capture the essence of a particular musician’s technique and style, and the sound of his/her voice or instrument. I think the recordings Pierre Sprey has made for Mapleshade Records are as good as any I have ever heard in the Jazz and Blues genre. But, consider how much better off you would be if your personal experience, rather than someone else’s, was the reference.

I am always amazed, and left dumbfounded, by the number of people who listen to (and sometimes “judge”) sound systems and throw out all sorts of flowery adjectives to describe what they hear, but could not tell you if that instrument playing in the back, stage left, is a piccolo or a flute, or a soprano sax or a clarinet, or whether the trumpet player is using a mute, and if so what kind, or whether the drummer is holding his high hat while he taps it. I can go on and on about thus, but will summarize my thoughts by simply saying that if you want to be able to properly tune/EQ a playback system, go listen to live music, especially unamplified, of all genres, and do so often. And, become a student of recording techniques and listen to recordings by those sound engineers and performers who place fidelity of sound above all other commercial objectives. Only then will the other tools be able to be used to achieve the best possible music playback results.

 

Good Advice.
I found myself answering your instrument questions as I read along.
I am sure I can correctly answer all of them but the one regarding which trumpet mute is being used.
BTW, does it have to be a professional live orchestra, or can it be my daughter's music class recital?
She wouldn't have to know why I'm so interested in her next concert.
Wow! Two birds with one stone!

Bret
PPI-ART COLLECTOR

 

Thank you!!!

 

Buzzman, thanks for sharing these additional resources and insights into tuning. You're way ahead of me in terms of practical experience but the responses and additional suggestions offered on this thread (sqnut) is what makes for a far better learning opportunity. I now have far more info than what I started with and hopefully will not have to suffer hair loss because of an aggravating tune! Lol

 

Like with many things, this OP's link is a useful guide to help understand some basic aspects of tuning. I know I have used many similar links in the past to help identify some trouble spots more easily.

the "fun" in car audio tuning is the environment and like any post production tuning is trying to understand cause and possible effects.
Im not going to even pretend that I know what every single instrument sounds like let alone isolating it down to particular sonic signatures etc...

but through experimentation and using guides like the above people can start to learn to identify trouble frequencies more easily and target them .

Then starting to understand that if you boost say 6khz to get more sizzle on a high hat , that you also increase sibilance on vocals.
Increasing 1.6-2.5 can make instruments have more attack, but also can make vocals,especially female, sound harsh.

So its these sort of interactions that need to be kept in our minds eye when using these sorts of tutorials. But in no way Do I think using them causes any harm. it at least people get moving on learning to tune themselves.
and can get them in the right ballpark to finding trouble areas.

 

^^Good point! I find that domino effect when making EQ adjustments is the killer for me. How boosting and cutting can have pos/neg effects across the spectrum. You can have an almost perfect tune on one reference disc and have to go back and adjust the same tune for what may be considered 'non-reference' material - which is what I mostly listen too. In the end it's fun, very engaging and is teaching me whole lot about addiction LOL

 

Unless I'm missing something, I didn't see it mentioning at what point mono fequencies stop and where stereo frequencies begin.

 

Here's a pic.

Bret
PPI-ART COLLECTOR

 

Bret, that is really precious! Nourish her love of music and you both will be rewarded. And, cherish moments like that pictured, they pass so quickly.

 

Well, i have no idea how real instruments sonds like. Not to say every instrument sounds the way it is, and there are lots of difference between same instrument types, let alone the sound producer, who make them sound even more different between recordings...

Live performance is must to understand what should you hear, but have nothing in common to EQ and tuning. It's nice to know, but it doesn't guide you thru fixing the sound environment...

Pick some nice set of headphones which typically sound flat, portable player with a copy of music you tune with, and do A/B testing.

Usually, i do a lot of listening to music i like from different genres every time i change something in EQ/xovers. Because 90% of fixes in single song ruin other songs. Make a vocals sound sweet and forward, and get some rock to sound harsh. Make the rock to sound deep and dark, and get classics and jazz to sound dull and lifeless...

Everything is nice as long as you don't turn your engine on, and don't drive at 60mph. Then you get no midbass, no bass, no body of instruments - just some shrill in your ears from tweeters. Tune the system for driving - and get owerhelming bass when you park.



As a side note... Speakers is the limit. Take some metal thing that rings, slam it hard, and hear the sound. It really "kicks" your ear drums, and is way more powerfull than yours tweeters. Tweeters can't produce such "punch" no matter how do you EQ them. Horns could do that for you...

 

Everything is nice as long as you don't turn your engine on, and don't drive at 60mph. Then you get no midbass, no bass, no body of instruments - just some shrill in your ears from tweeters. Tune the system for driving - and get owerhelming bass when you park.

I couldn't agree with you more S3T. I'm a firm believer, not in a flat response, but a relatively flat response - i.e. a response that is flat, relative to the environmental noise. I've actually gone so far as to run an RTA in my car whilst driving down the road. I then shape my response curve to compensate for that which will be drowned out by road noise - which can actually reach 80db on a rough road.

 

Buzzman,

I agree that 'live' sound would be the ideal reference. As a recording engineer yes you would have to be intimately familiar with this sound to know that you are capturing all the nuances while recording. But even here, while live music can have dynamics of +/- 30db or more, I'm not sure if any media can capture this. So now its down to whats recorded and not live.

Fast forward to the guy listening to this recording in possibly the worst environment, where in this is what your speakers are putting out and this is what you're hearing at ear level. That's only for one side. These are Andys FR graphs for sound recorded 1" from the cone and at ear level.

That is the impact of the environment in a car. I'm afraid the subtle nuances are now lost. In a car one is using the tuning tools driver placement to reduce the impact of the environment. So well recorded music on a decent 2ch setup is a good point to start, a top 5 competition cars would be even better cause then its apples to apples. To say that unless you are familiar with each nuance of sound, you shouldn't be tuning is a bit OTT.

On the tuning tutorial, while I mentioned that with sound everything is connected and gave the example of harmonics to show that, I missed other level of connectivity which Mic highlighted. That's about the only thing I would add in my tuning post. Keep in mind the post is for the average hobbyist who has some dsp to play with. That post though was specifically for MrMoto who runs the p-99.

Last but not least, I have to thank you and people like you, who are dedicated to putting out great recordings. Your efforts are much appreciated

Arun

 

Buzzman,

I agree that 'live' sound would be the ideal reference. As a recording engineer yes you would have to be intimately familiar with this sound to know that you are capturing all the nuances while recording. But even here, while live music can have dynamics of +/- 30db or more, I'm not sure if any media can capture this. So now its down to whats recorded and not live.

Fast forward to the guy listening to this recording in possibly the worst environment, where in this is what your speakers are putting out and this is what you're hearing at ear level. That's only for one side. These are Andys FR graphs for sound recorded 1" from the cone and at ear level.

That is the impact of the environment in a car. I'm afraid the subtle nuances are now lost. In a car one is using the tuning tools driver placement to reduce the impact of the environment. So well recorded music on a decent 2ch setup is a good point to start, a top 5 competition cars would be even better cause then its apples to apples. To say that unless you are familiar with each nuance of sound, you shouldn't be tuning is a bit OTT.

. . .

Arun

Arun, I appreciate your point of view, but let me clarify my position as I don't think you fully understood my point. I did not say that one shouldn't tune a sound system unless one is familiar with the sonic nuances of live musical instruments and voices. Rather, I said that in my opinion one cannot "properly" tune (or judge or assess the merits of a sound system) without having listened extensively to live (preferably unamplified) musical instruments and voices, and gained some level of music education. Otherwise, you will largely be walking around blindly, and often aimlessly, because you don't have the necessary reference embedded in your brain against which to make judgments. I do believe that one can benefit from listening to music reproduced on a fine 2 channel system, or a top sound quality automobile, in a number of ways. However, for the listener who has not listened extensively to live, unamplified music, what is the reference against which he or she can judge the merits of what he or she hears through that 2-channel system or in that supposedly reference automobile? The listener's system? Sure, he or she will be able to determine where their system differs in comparison, but how do they know which is "right" and what sonic results they should be striving to achieve? In my view, having live, unamplified music as a baseline reference is essential for anyone pursuing this hobby to achieve maximum performance and enjoyment from their sound systems.

I know well the difficulties the mobile environment presents to optimal playback of music. There are challenges that will never be overcome, and many that have to be overcome before you can even remotely claim to have achieved great music playback in your vehicle. But, because I have played music, regularly attended live performances (both unamplified and amplified), and continue to study and learn about music reproduction and acoustics, I have an excellent idea of what needs to be achieved in my vehicle before I can consider my system a reference quality playback system. I am able to experiment and listen to the results, and because I have as a reference in my brain the sound of the real thing, I know when what I hear is "right" to me, or as close to being "right" as I can get. And, if something is missing or "lost' as you put it, wouldn't it be nice to know what that is? I am not suggesting that my sense of musical "rightness" is universal. I am sure there are many who might disagree with me on a number of fronts because we do not all hear things the same. But, I do trust my ears and all I seek is what gives me the most aural satisfaction, based on my view of what sounds "right." Now, even though the live result is my ultimate reference, we tune our systems by relying on recorded performances. But, the analysis is the same. How can one ascertain whether a recording used to tune a system truly captures the essence of real musical instruments and voices, if one has not listened extensively to live music? I think there is general agreement that our goal in this hobby is to execute a music playback system able to reproduce as accurately as possible what is recorded, and as close to the live music experience as possible. So, again I say it's to everyone's benefit to listen to live music (unamplified as much as possible). Not only will your music listening and tuning skills improve, but you will grow culturally.

 

While the chart gives cues to what happens at each frequency, don't under estimate the role of harmonics on the overall sound. How you set 200hz will affect 400hz like 3khz will affect 6khz and so on.

Can you clarify this? Are you referring to harmonic distortion? Otherwise I am unsure how boosting 200hz "will affect 400hz". Instruments playing tones/music create harmonics. Reproduction equipment (EQs, speakers, amps, etc) create harmonic distortion (a specific form of harmonics). Unless you are using a very broad (low q) filter or a really crappy EQ with high THD adjusting gain at 200hz should NOT affect 400hz.

 

While tuning, have you never had a situation where the mids / upper mids sound stretched, the highs hollow and you loose the snap in your mid bass, all because the 80-200 range is too hot? Acoustically what you do in say, the 80-200hz range will impact your entire spectrum, not just the 80-200 range.

That is a challenge for the recording systems but the "media" (CD, EAC, and others) has been around a long time. LPs can even get to around 45db (check out the audioholics website). The real problem is not the media it is typically the engineer doing the recording and the consumer who buys this low quality trash.

Even the best recorded LP will not sound the same as 'live'. That is the point that even Buzzman is making.

 

while live music can have dynamics of +/- 30db or more, I'm not sure if any media can capture this.

That is a challenge for the recording systems but the "media" (CD, EAC, and others) has been around a long time. LPs can even get to around 45db (check out the audioholics website). The real problem is not the media it is typically the engineer doing the recording and the consumer who buys this low quality trash.

 

This quote:

While the chart gives cues to what happens at each frequency, don't under estimate the role of harmonics on the overall sound. How you set 200hz will affect 400hz like 3khz will affect 6khz and so on.

Is VERY different from this one:

While tuning, have you never had a situation where the mids / upper mids sound stretched, the highs hollow and you loose the snap in your mid bass, all because the 80-200 range is too hot? Acoustically what you do in say, the 80-200hz range will impact your entire spectrum, not just the 80-200 range.

The first infers that adjusting a freq will influence harmonics of that frequencey (which should not happen). The second seems to address relative levels and how they affect the perception of music (this absolutely does happen).

If the second quote (boosting/cutting one freq has affects on how we perceive the rest of the spectrum) was your intent then I agree with you wholeheartedly.

Peace