Tuning for below the dummy level

So is there a place that has a DSP tutorial for someone below the dummy level? Because I literally don't understand any of it. I've tried to read the tuning 101 tutorials here and on other sites but they assume that the reader understands basic terminology, and I don't.

I tried to read a simple tuning sticky by chithead but I who was lost after the first paragraph. Then when I saw at the bottom that if you need cliffs this thread is not for you, I tried
The essentials of sound quality. I barely made it through the first paragraph there as well. I watched all of the Car Audio Fabrication videos but I still don't get what the difference is.

I guess my point is, where is the tutorial that begins with basics like which speaker to tune first, what you're trying to get out of it, why do it in the first place.

As an example I know that sound deadener makes things rattle less, which makes everything sound better because there's less background noise so you hear more of the music. How it does that I have no idea. I know that butyl is some sort of sticky rubber with aluminum on the back, and when you tap something that has it compared to tapping something that doesn't there's no echo just the first thud so that makes obvious sense.

I spent money on an Axxess DSP Lite but I feel like I just wasted money because I have no real understanding of what it does and why and what the difference will be. Is there anything that's that basic that I can look at around here that explains the how and the why of a DSP in that basic of terms?

Lewis King

Hi Lewis!

You seem to want to understand the "why" part quite a bit. I like analogies and using photography is one that most people can understand without needing to know jargon and it's really approachable.

A photographer puts great effort into taking the perfect picture. They plan for it, they are patient, they try over and over until they get just the right moment and then capture it. This could be similar to musicians creating music; both are creative processes that require passion and time.

A photographer will almost always do some post processing on the image like adjusting the brightness, changing some colors, removing a distracting object in the background, and so on. This is also part of the creative process that the photographer puts time and effort into, to help bring their photograph to life as intended. For audio, this is like the musicians taking their studio recordings and having them mixed and mastered so that all the instruments sound just right, and they can choose the vocals from the second recording but the drums on the first recording, make that kick drum sound fat but not overpower the bass guitar, etc. The musician at this point is complete with their creative process and the art is ready to be shared.

A serious photographer will go to great lengths to print their art on paper or canvas using high quality inks that will not fade over time, using printers that are color calibrated so that what the photographer saw on the screen is exactly what you see on the print. Some photographers will even control the lighting used to view the pictures if they are on display at a museum or expo. They care deeply about making sure you will experience that picture as intended. If you really enjoyed browsing pictures or following a photographer's work, you might put some effort into calibrating your monitor so that the colors you see at home are closer to the colors that the photographer intended.

Music, on the other hand, has absolutely no control over how you listen to it. You are free to listen to the AM radio and kinda-maybe hear the music, or use some cheap headphones on an airplane and strain to hear the music over the sound of the engines and wind. You could also, if you were really dedicated, try to reproduce the experience that the artist intended so that you can listen and enjoy that music the way it was meant to be.

DSP, in this analogy, would be like putting effort into making sure your monitor had the correct color balance and brightness so that the art that you see is the same art that the artist intended. Actually, DSP is used in your monitor to adjust the colors so ... yeah.

For the car and back to your question of "why", know that what you are hearing is very likely not what the musician was hearing when were creating their music. The experience in cars is poor, an not a good reproduction of the experience you are meant to enjoy. DSP, in this case, is the tool you use to make your listening environment (the car) behave more like the listening environment that the musicians used (recording studio). If you want to make the music sound like it is supposed to, you gotta change something, and DSP is how we do that.

The "how" part is not too complicated, but there are so many different methods that they can seem contradictory and like an overwhelming noisy mess. In short, you want the frequency response at your listening position (usually driver's headrest) to be similar to the frequency response in the recording studio (or whatever your reference stereo is). We adjust frequency response using equalizers, exactly the same as those ubiquitous Bass and Treble knobs on almost every stereo, except instead of two knobs we can have many more knobs to be much more specific about how to adjust the frequency response. We need all those extra knobs to twist because the frequency response in a car is "damaged" in many small ways, so we need many smaller knobs to correct it.

In addition to frequency response, we want all of the speakers to cooperate such that the sound reaches your listening position at 1) the exact same time and 2) in the same polarity. This is a bit like watching waves in a pool where there are many smaller waves moving around but sometimes they meet together at the same spot and you'll see a large wave for just a moment. This is the same concept with sound. You want all of the sound waves from all of the speakers to collide at the same time at your listening position so that the energy from each of the individual waves sums together into one larger wave right there at that specific spot.

To get the sound waves to arrive at the same time, we use time delay. Sound from the nearest speaker to you will naturally arrive first, and sound from the speaker furthest from you will arrive last. To make the sound waves arrive at the same time, we play sound from the furthest speaker first, then wait a little bit for that furthest sound wave to approach you, and when it gets close enough then we play music from the closer speaker. The pause between playing the further speaker vs playing the closer speaker is time delay. In very rough terms, sound travels at just over 1ft / millisecond. So if your closet speaker is 5 feet closer than your furthest speaker, the time delay on the nearest speaker would be somewhere around 5 milliseconds.

Last, when the sound waves arrive at the listening position we need them to be in the same polarity. Just the same as in a pool where many waves can also meet to create a valley, sound can combine such that one sound wave can cancel out another. This is polarity, and if one speaker's polarity is opposite the other then you get cancellation and this is most noticeable because the bass will appear to decrease. Polarity is controlled by flipping the positive and negative (red/black) wires on the speaker itself. It is not always convenient to take apart the car to reach the speaker wires however, so we can do the same thing with a DSP using a mouse click.

Those are the fundamentals: frequency response, time delay, polarity.

You will also hear a LOT about phase which is totally important, and absolutely daunting to try to understand without getting some intuition of the fundamentals. I wouldn't try to chase phase-related stuff until you get more comfortable, phase will be a huge distraction until then.

Oh! Forgot something.

When I say make your stereo sound like the musician intended, that is only one ideal. Some people enjoy the pursuit of perfection and a system that is very technically correct.

The majority of people usually want their stereo to sound "good" to them. The word good is very subjective, and what is enjoyable for me might not be what is enjoyable for you.

And bam, the house curve is born. House curves (or target curves) are like the calibration reference that you are aiming for as an end result. I can tune my car to a house curve and then I can tune your car to the same house curve and they should sound very similar. Everyone likes their stereo to sound a little different, so you will also find a lot of talk about house/target curves. There are some common ones that people start with and after gaining some more practice you'll start to tinker with the target and experiment with different ones, very likely creating your own personal house curve because that is what will sound best to you.

In the beginning, don't worry about which target you choose. Doesn't matter at all. The only thing that's important in the beginning is learning how to use the tools and learning how to adjust the system to behave the way you want. When you can do that, then you can worry about which house curve to choose and what it will sound like. Until then, maybe choose one target and stick with it until you're happy that you can get repeatable results.

This one is pretty good too:
https://testgear.audiofrog.com/wp-co...y-it-Works.pdf

Okay so say that I bypass the microphone, the pink noise, the r e w, laptop and tune my system by setting all of my audio equipment to flat, setting the gains on my amplifiers correctly, and sitting in my car with the Axxess DSP software on my cell phone. What is the worst case scenario if I do that?

I'm trying to get a baseline comparison so that I can understand the value of following that process as opposed to me taking advantage of the benefits of the DSP software and doing it by myself.

I hope I explained that clearly but do you understand what I mean?

Ah, that is a different question than what you asked.

A few reasons.
1) to achieve a great sound stage, you need to be able to make sure your levels for each speaker are appropriate across all frequency bands. Not just pure spl level.

2) You also need to be able to cross speakers over appropriately, without a microphone to measure, that is very hard to do.


3) For repeatability and knowing what you like for future.

4) And for trying different things and knowing what you are changing.

5) I've never heard a car that was tuned by ear that was remotely as good as one via a microphone and ear for final. I suppose if you were like a level 15 on Harmans how to listen or similar software, you could do well for frequency response differences. But there is more to it than just that.


There are more that I am sure others will chime in on too.

But look at the bright side, if you buy a microphone, you can sell them for close to what you paid. So you really aren't out much money to try it out and see.

So really the difference is like starting with a clean sheet of paper instead of starting with an old one and erasing everything. It's still paper but whatever you use it for is still gonna have those erasure marks behind it.

The microphone only costs 20 bucks and I already have a laptop so I'd probably keep it. I need a microphone for my YouTube channel anyway.

Side note, I looked up the components of your system. I've never heard of any of those components except for the alpine amps. What are the benefits of those speakers?

I spent money to get Hertz Dieci components for the front and coaxials for the rear for sound quality. I'm guessing that your system will blow those out of the water and I'm trying to learn more. Can you tell me the difference?

mid level gear + great tune > "the best" gear + mediocre tune

Your nertz drivers should be a good start. Get install complete and solid, get tune dialed in, then listen to it for a while. There will be stuff you really like and some you don't. Addressing the issues is where it gets tricky. Before swapping gear you have to eliminate tune and/or install problems.

Are there any rules for using 1 crossover and 2 DSPs? One for front stage, one for rear fill? Crossover for assisting the overall levels while you're driving?

I'm sorry I meant to say an EQ with 2 DSPs? I'm thinking about doing that.

Quote:

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Originally Posted by Original wis

I'm sorry I meant to say an EQ with 2 DSPs? I'm thinking about doing that.

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most processors have eq and unless you just can't find a dsp with enough channels use 1. Pick out random build logs and see how many you find with multiple processors ;)

The EQ is for when I'm driving and I want to boost or lower a frequency on all speakers at once. For like, if a cymbal is too loud but everything else is ok. I can reduce that immediately and turn it back up on the next one.

You're right though I got a bunch of info about latency compensation and some other things that make sense. So I'm gonna run the DSP for the front stage and use the EQ for the rear fill and subwoofer.

Quote:

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Originally Posted by Original wis

The EQ is for when I'm driving and I want to boost or lower a frequency on all speakers at once. For like, if a cymbal is too loud but everything else is ok. I can reduce that immediately and turn it back up on the next one.

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If tuned correctly you won’t get instruments that jump out, and as to your question about two dsps, you’re asking very basic questions and trying to understand stuff, why are you insisting on throwing more than 8 channels and a two way with widebands or three way front and a sub into the mix

you're just adding more crap to more crap and not going to understand any one part, keep it simple for your first system with dsp, stop trying to do something most tuners wouldn’t even consider, it will sound junk!!

I truly don't see an upside to your plan. Most dsp units have at least the option for a controller with presets.

downsides:
tuning while driving is bad, don't do it
adding extra components to signal chain is an invitation for noise
extra cost and complexity (have you priced processors?)

Start with 1 good processor, then evaluate, my $.02...

You're right I actually thought about it and what I'm going to do is install my system the way that I originally intended and add the DSP to it so that I can learn the complexities of it in real time. I'll graph the responses, take screenshots, do all the work and I'll post it.

That way if it does sound like ass can say I told you so we're all laugh about it and I'll go back and learn how to fix it.

I think that sounding like ass is the worst case scenario and that can pretty much be fixed. And I think it'll be an awesome learning experience to clean up my own mess.