SeRiousZX2
12-09-2008, 01:26 PM
Start here (http://teamzx2.com/showthread.php?t=10371) first
CH. 2 THE POWER OF KNOWLEDGE
In Chapter 1 we took a look at a very typical situation that happens daily. You had a first time stereo purchase by a customer that had little knowledge about the industry. I was once that guy. I have also been on the other side as the salesman. I have seen hundreds, no thousands, go through this exact same situation.
Even after 16 years in the industry, I learn new things every week. After working for numerous shops being a salesman/installer and running my own store, I can still say that there is more to learn. Technology is constantly changing the car audio industry. New products with new features, new installer tools, new types of building material, ect keeps things new and fresh. So, if I can admit that there is more to learn, you should feel ok doing the same.
Back to Chapter 1 to finish the story. To make it have meaning, we will call our customer in Chapter 1 Carl. After several weeks of rocking it out, Carl becomes very displacement about his stereo. It seems his stereo just doesn’t measure up to many of his friends. Carl’s biggest issue is the bass and distortion. There always seems to be too much of one and never enough of the other. Had Carl stuck with buying his system from the car audio shop instead of Wally World, he probably would have ended up with a better system. But that’s not always the case. Sometimes the systems come out the same or even worse. A lot depends on the knowledge, expertise, and experience of the staff.
Paying that extra $50 is usually a good thing when it comes with the expertise of a staff that can help you. Should money be a concern but nothing too serious, I always recommend finding a small/medium local shop that has a decent reputation with custom work. When you find this shop, find a salesman that you can relate to and give him/her a very general idea of what you want. Give them a reasonable spending limit ($1500 - $5000), you trust them, and give them the freedom to come up with whatever they want. Usually in a small shop, reputation and pride in on the line and you are pretty much guaranteed to get more than your moneys worth and the system will sound good.
For some, it’s the feeling of listening to a system that they built with their own hands. For others, they prefer the “pick and choose” method. Hopefully this book will bring to light some fundamental truths about car audio. Just remember, marketing and ads do not always tell accurate information.
Now back to Carl. Carl’s problem is that the bass only sounds good at low volume. As the volume increases, it begins to sound like crap. Carl likes his music extremely loud and on several occasions turned the volume all the way up. The last time he did this one of his BIG woofers went POP!!! Carl was confused on how a sub rated at 150 watts could be blown by a 100 watt amp.
While running my car audio shop, I saw customers like Carl all the time. They would come in complaining about how bad their system sounds. My self or one of my installers would go out to the car for a listen. First thing we would do is turn the EQ on the headunit to flat, balance and fader to center. Carl’s system sounded very thin. No highs, bass was barely noticeable, and when you turned it up it got muddy. Carl explains that he usually has to turn the bass up but it still sounds like crap. I have Carl demonstrate this, and yes, it sounded like crap. Carl mentions that it used to sound worse because he recently added an amplifier to the door speakers. Before they were ran to the headunit and they distorted really bad with the volume up high.
I broke down and asked Carl what kind of amp it was. He jumped out and took me around to the trunk. There it was, this tiny amp with a 5 AMP fuse. On the case was a typical writing of “80 x 4 MAX Power”. He proudly claims that it only cost him $50. Looking at his system, this is what he currently has:
CD player with rear RCA outputs – Value: $200
5.25” Coaxial door speakers – Value: $75
5x7” Coaxial rear deck speakers – Value: $75
Carpeted box with 2 10” woofers – Value: $190
Sub amplifier with a 200 x 2 max rating – Value: $180
Amplifier with a 80 x 4 max rating – Value: $50
2-Way electronic crossover – Value: $50
From here, Carl follows me inside for a chat.
Explain that he doesn’t have near enough bass and he agrees. I let him know that his current system is letting him down. He explains that after talking with friends, they were the ones that suggested he needed the small amp and an active crossover for the door/rear speakers. He then ask what wrong with it.
I let him know that his subs were under powered, his power cable was way to small, his smaller amp was horrible, the door/rear speakers were crossed way to high, the headunit EQ only goes down to 50 Hz, and the sub box is tuned for 40 Hz. The small amp has poorer specs than the CD player, the gain is set too high, and gain on the sub amp is set too high. Another issue is that the door/rear speakers have a 91 dB rating and the subs have an 85 dB rating. That means to play at the same loudness the sub woofer needs over twice the power. The smaller amp has a total of about 30 watts clean, and the bigger amp is only about 90 watts clean. So you see they play at the same volume. What you want is for the sub woofer to play at a level 3 to 9 dB louder than the front speakers. To do that you could double the power of your sub amp 3 times, or get a better sub woofer. I always recommend the later.
On of the biggest secrets to good sounding car audio is simply “balance”. You want to hear each note in the music without coloration. If a system exhibits real peaky frequency response that is coloration. The lowest note that our ears can hear is 20 cycles per second. If you take the speed of sound and do the math you will see that the sound wave travels over 40 feet before the next wave follows it. So a 20 cycle note would be 20 waves spaced around 40 feet apart in one second. The highest note we can hear is 20,000 cycles. Most music does not exceed 16,000 cycles. Some people can't hear past 12,000 cycles, and if you continue to listen to your car stereo when it is distorting, you will be one of them.
In Carl’s case, his bass response sounds like it only goes down to about 75 cycles, or in simple terms, no bass. Carl’s system is capable of going down to 50 cycles. I have him follow me out to his car. I wanted to point out a few things about his sub box. He pops the trunk and there it is. This box that 48 x 13 x 13 is stuffed all the way in as close to the seats as possible. This pitiful box itself is so thin that it too is creating a very annoying squeak. Carl was given two options of doubling his amplifier power 3 times or getting a new sub woofer, As always, I recommend getting a new sub woofer. Carl thinks about it for a minute and asks how much power would that be. I quickly pointed out that at a rating of 200 x 2 max. power he should get one that is 3200 watts. Carl quickly realizes he can’t afford an amplifier that big. And if he could, the cheap sub woofer wouldn't handle the power anyway.
At this time, I unhook his box and take it into the shop. In there I have 20 or so different sub woofers on a switcher for demonstration and testing reasons. I hooked up his box to switch one. His box has two tens, with an efficiency of 85db. From here I demonstrated his box on a good flat CD source with an amplifier similar to his own. His eyes got big when for the first time he heard 50 cycle notes from his box. I tell him to just wait and let me finish. This, I said, is what your box should sound like. This is as good as your box can sound. I explain to Carl that his box was a little large for his trunk. In fact it is so large that it obstructs the air flow in his trunk and does not breath properly.
I then hook up a properly and professionally built box, about 1/2 the size using only one 10 inch woofer. The smaller sub woofer has a reference efficiency of 91db and is ported to achieve 12 dB of gain centered at 38hz. That makes it well over twice as loud as Carl's box on 35hz frequencies. Carl almost crapped his pants. It took about 15 minutes for Carl to wind back down. Thought run through his head, “Twice as loud with half as much”. This is the difference between a good box and a bad box. What makes a good box good is design and craftsmanship, and the proper materials.
On the way back out to his car Carl asked me if I could make him a box, and he would sell the one he has. I told him to sell the small amplifier as well. He could use the cash to buy some tweeters, better power wire, and a noise filter.
We are going to take Fred's car stereo and re-install it. But before we do that, we will go over some of the basic facts about car stereo components. One of the most miss- understood things is BASS and how to achieve it efficiently. In the next chapter, we will discuss how bass works and the most common problem found in car stereo systems, cancellation.
CHAPTER 3 COMING SOON!!!!
CH. 2 THE POWER OF KNOWLEDGE
In Chapter 1 we took a look at a very typical situation that happens daily. You had a first time stereo purchase by a customer that had little knowledge about the industry. I was once that guy. I have also been on the other side as the salesman. I have seen hundreds, no thousands, go through this exact same situation.
Even after 16 years in the industry, I learn new things every week. After working for numerous shops being a salesman/installer and running my own store, I can still say that there is more to learn. Technology is constantly changing the car audio industry. New products with new features, new installer tools, new types of building material, ect keeps things new and fresh. So, if I can admit that there is more to learn, you should feel ok doing the same.
Back to Chapter 1 to finish the story. To make it have meaning, we will call our customer in Chapter 1 Carl. After several weeks of rocking it out, Carl becomes very displacement about his stereo. It seems his stereo just doesn’t measure up to many of his friends. Carl’s biggest issue is the bass and distortion. There always seems to be too much of one and never enough of the other. Had Carl stuck with buying his system from the car audio shop instead of Wally World, he probably would have ended up with a better system. But that’s not always the case. Sometimes the systems come out the same or even worse. A lot depends on the knowledge, expertise, and experience of the staff.
Paying that extra $50 is usually a good thing when it comes with the expertise of a staff that can help you. Should money be a concern but nothing too serious, I always recommend finding a small/medium local shop that has a decent reputation with custom work. When you find this shop, find a salesman that you can relate to and give him/her a very general idea of what you want. Give them a reasonable spending limit ($1500 - $5000), you trust them, and give them the freedom to come up with whatever they want. Usually in a small shop, reputation and pride in on the line and you are pretty much guaranteed to get more than your moneys worth and the system will sound good.
For some, it’s the feeling of listening to a system that they built with their own hands. For others, they prefer the “pick and choose” method. Hopefully this book will bring to light some fundamental truths about car audio. Just remember, marketing and ads do not always tell accurate information.
Now back to Carl. Carl’s problem is that the bass only sounds good at low volume. As the volume increases, it begins to sound like crap. Carl likes his music extremely loud and on several occasions turned the volume all the way up. The last time he did this one of his BIG woofers went POP!!! Carl was confused on how a sub rated at 150 watts could be blown by a 100 watt amp.
While running my car audio shop, I saw customers like Carl all the time. They would come in complaining about how bad their system sounds. My self or one of my installers would go out to the car for a listen. First thing we would do is turn the EQ on the headunit to flat, balance and fader to center. Carl’s system sounded very thin. No highs, bass was barely noticeable, and when you turned it up it got muddy. Carl explains that he usually has to turn the bass up but it still sounds like crap. I have Carl demonstrate this, and yes, it sounded like crap. Carl mentions that it used to sound worse because he recently added an amplifier to the door speakers. Before they were ran to the headunit and they distorted really bad with the volume up high.
I broke down and asked Carl what kind of amp it was. He jumped out and took me around to the trunk. There it was, this tiny amp with a 5 AMP fuse. On the case was a typical writing of “80 x 4 MAX Power”. He proudly claims that it only cost him $50. Looking at his system, this is what he currently has:
CD player with rear RCA outputs – Value: $200
5.25” Coaxial door speakers – Value: $75
5x7” Coaxial rear deck speakers – Value: $75
Carpeted box with 2 10” woofers – Value: $190
Sub amplifier with a 200 x 2 max rating – Value: $180
Amplifier with a 80 x 4 max rating – Value: $50
2-Way electronic crossover – Value: $50
From here, Carl follows me inside for a chat.
Explain that he doesn’t have near enough bass and he agrees. I let him know that his current system is letting him down. He explains that after talking with friends, they were the ones that suggested he needed the small amp and an active crossover for the door/rear speakers. He then ask what wrong with it.
I let him know that his subs were under powered, his power cable was way to small, his smaller amp was horrible, the door/rear speakers were crossed way to high, the headunit EQ only goes down to 50 Hz, and the sub box is tuned for 40 Hz. The small amp has poorer specs than the CD player, the gain is set too high, and gain on the sub amp is set too high. Another issue is that the door/rear speakers have a 91 dB rating and the subs have an 85 dB rating. That means to play at the same loudness the sub woofer needs over twice the power. The smaller amp has a total of about 30 watts clean, and the bigger amp is only about 90 watts clean. So you see they play at the same volume. What you want is for the sub woofer to play at a level 3 to 9 dB louder than the front speakers. To do that you could double the power of your sub amp 3 times, or get a better sub woofer. I always recommend the later.
On of the biggest secrets to good sounding car audio is simply “balance”. You want to hear each note in the music without coloration. If a system exhibits real peaky frequency response that is coloration. The lowest note that our ears can hear is 20 cycles per second. If you take the speed of sound and do the math you will see that the sound wave travels over 40 feet before the next wave follows it. So a 20 cycle note would be 20 waves spaced around 40 feet apart in one second. The highest note we can hear is 20,000 cycles. Most music does not exceed 16,000 cycles. Some people can't hear past 12,000 cycles, and if you continue to listen to your car stereo when it is distorting, you will be one of them.
In Carl’s case, his bass response sounds like it only goes down to about 75 cycles, or in simple terms, no bass. Carl’s system is capable of going down to 50 cycles. I have him follow me out to his car. I wanted to point out a few things about his sub box. He pops the trunk and there it is. This box that 48 x 13 x 13 is stuffed all the way in as close to the seats as possible. This pitiful box itself is so thin that it too is creating a very annoying squeak. Carl was given two options of doubling his amplifier power 3 times or getting a new sub woofer, As always, I recommend getting a new sub woofer. Carl thinks about it for a minute and asks how much power would that be. I quickly pointed out that at a rating of 200 x 2 max. power he should get one that is 3200 watts. Carl quickly realizes he can’t afford an amplifier that big. And if he could, the cheap sub woofer wouldn't handle the power anyway.
At this time, I unhook his box and take it into the shop. In there I have 20 or so different sub woofers on a switcher for demonstration and testing reasons. I hooked up his box to switch one. His box has two tens, with an efficiency of 85db. From here I demonstrated his box on a good flat CD source with an amplifier similar to his own. His eyes got big when for the first time he heard 50 cycle notes from his box. I tell him to just wait and let me finish. This, I said, is what your box should sound like. This is as good as your box can sound. I explain to Carl that his box was a little large for his trunk. In fact it is so large that it obstructs the air flow in his trunk and does not breath properly.
I then hook up a properly and professionally built box, about 1/2 the size using only one 10 inch woofer. The smaller sub woofer has a reference efficiency of 91db and is ported to achieve 12 dB of gain centered at 38hz. That makes it well over twice as loud as Carl's box on 35hz frequencies. Carl almost crapped his pants. It took about 15 minutes for Carl to wind back down. Thought run through his head, “Twice as loud with half as much”. This is the difference between a good box and a bad box. What makes a good box good is design and craftsmanship, and the proper materials.
On the way back out to his car Carl asked me if I could make him a box, and he would sell the one he has. I told him to sell the small amplifier as well. He could use the cash to buy some tweeters, better power wire, and a noise filter.
We are going to take Fred's car stereo and re-install it. But before we do that, we will go over some of the basic facts about car stereo components. One of the most miss- understood things is BASS and how to achieve it efficiently. In the next chapter, we will discuss how bass works and the most common problem found in car stereo systems, cancellation.
CHAPTER 3 COMING SOON!!!!