10 big bass secrets

#8 . SUSTAINED VOLTAGE

Amplifiers need Voltage. Good Voltage. Hopefully

better than 12.6 volts DC. 12.6 volts is a typical

automotive battery at rest. An automotive battery has

6 cells, each 2.1 volts, wired in a series. A charger with

higher voltage is needed to charge this battery. The

charger, in the form of an alternator, supplies the

charging power, at 14.4 volts, and also power to your

cars accessories when it is running. A typical alternator

will provide at 65+ amps of current at 14.4 volts. This

power is distributed to all of the power drawing

components of your car. Your dome light, your

computer, injectors, dash lights, headlights, power

seats, heater fan and more. Some of these are constant

and some are intermittent. Constant needs will reduce

the available power available to your aftermarket

stereo system. If your Alternator supplies 65 amps, and

your cars constant needs are 45 amps, you have 20

amps available to feed your system. If you use this 20+

amps, there will be no power to keep your battery

charged. If you use more than this available 20 amps,

you will be stealing power from your battery and

reducing your 14.4 volt running voltage to 12.6 volts

and even lower depending on demand. If this goes on

too long, your battery will deplete and may not start

your car next time.

Secret:

To keep your whole electrical system happy with a high

demand aftermarket stereo, you must upgrade your

electrical charging and storage system. Look for a

higher output alternator and battery with more

storage capacity.

Speaking of capacity, have you heard of a capacitor? It

is a common misconception, that a capacitor is a

magical device that creates and sustains voltage for

your amplifier. The truth is, this capacitor feeds off of

your supplied power and will affect your entire cars

electrical system. Every single electrical component in

your car will be affected by it. But what are the effects?

A capacitor is merely a battery with the ability to

charge and discharge at a rapid rate. This means, when

your cars accessories demand a great amount of

current in a hurry, your capacitor is there most willing

to give it up. In this scenario, this is an advantage

because, a capacitor will give up this power without

causing a big system voltage drop. The capacitor will

actually smooth the voltage of the system by charging

when voltage is high and discharging when voltage is

low. In the case of a high demand car stereo with

capacitor or capacitors, instead of a great variance in

system voltage caused by musical transients, the

overall system voltage will be reduced determined by

the capacity of the capacitors and the demands of the

stereo.

Wiring:

The voltage and current provided by your cars

electrical system need an efficient means of transport

to your amplifiers. Thick wiring is the way. Follow your

owners manual for recommendations. remember, the

longer your wires, the thicker they should be.

I've seen it a million times. A car stereo shop will install

a huge car stereo system. They will upgrade batteries,

capacitors, power wires and all. In the end, the

headlight dim to the beat. Why??? They ask

themselves. They implemented everything they could

to keep this from happening. The customer hates it. He

feels this is the sign of a ghetto system.

Another big secret.

Your vehicles electricity flows in a circle through your

car. All that power makes its way to your amps with

HUGE power wire but what about its return? It returns

to your batteries ground by way of the sheet metal.

This sheet metal is grounded to your negative terminal

by this tiny little wire connected to your fender. Oh no.

Our ground potential is limited by this little wire. Lets

fix it! There are two ways to fix this. Leave it alone. Let

your stock accessories use it for ground. Run ground

wires, similar to your power wires, from your amps

Negative terminal to your batteries Negative terminal.

Or, keep using your cars sheet metal and upgrade that

wire on your fender. I've

seen it done both ways. In the end, your headlights

and all of your cars stock accessories will be love you,

and your big system will now be getting the ground

potential it deserves.

#7 . ACTUAL AMPLIFIER OUTPUT

Your woofers need to be getting all the power they

deserve!

I like to over power my subwoofers. Not to hurt them,

but to use them to their potential. If you have a lot of

power on hand, you can feed your subwoofers nice

clean power, and they love it.

A subwoofer is designed to reproduce a sine wave. A

sine wave is a beautiful power signal created by an

amplifier within its electrical capabilities. If you run an

amplifier too hard, outside of its capabilities, That

beautiful sine wave becomes clipped at its extremes,

resembling a square wave, even more as it is overdriven.

A square wave is easy to display on an

oscilloscope, but impossible to accurately reproduce

by a subwoofer. A subwoofer fed a square wave can

only attempt to track this challenging signal and where

it fails, heat is created. A square wave asks a subwoofer

to stop and start on a dime, and to reproduce

frequencies it wasn't designed for, all at the same time.

This can be good for a quick burst in an SPL

competition but bad for a listening session.

Peak power vs. RMS.

Here is a section I am excited to share.

Secret.

THERE IS NO SUCH THING AS PEAK POWER!!!

Are you surprised? Like when you found out a woman

is not born with all the eggs she will ever have? Like

when you discovered there was no Santa Claus?

So, as it turns out, "PEAK POWER" is code for

"Exaggerated" and "Distorted". If you want your

subwoofer to see 200 watts RMS, and 400 watts peak,

you will need an amplifier that will put out 400 watts

RMS. This is because if you buy a 200 watt amp, you

will be feeding your subwoofer dirty, clipped power

beyond 200 watts. Every amplifier is clean up to a

point, at which distortion arrives. Clipped waves cause

this distortion. Current limits cause the clipping.

A quick (but non scientific) way of determining total

amplifier output is to add up the fuse values and add a

zero. This would tell me that if my amp has two 40 amp

fuses, I can expect maybe 800 watts from a

class D amp and maybe 30 percent less from a class AB

amp. Class D amps are more efficient.

Use this only when you can't test properly with a fully

regulated power supply, multimeter, oscilloscope and

tone generator. The power supply will ensure proper

voltage. The Oscilloscope will ensure your wave is not

clipped. The multimeter will measure output voltage

across the load. The tone generator will provide the

signal. It can be a device or a test tone CD. Play your

tones into a speaker or load with your Multimeter

across the output terminals. You can read the output

with the VAC setting. Convert the voltage into watts by

using the Ohm's formula, P=E^2/R. This means,

Voltage

X Voltage / resistance = watts. here is an example...

25 volts X 25 volts = 625

625(volts) / 2(ohms) = 312.5(watts)

Our Subwoofer system has a resistance of 2 ohms, so

625 divided by two equals 312.5 watts.

This is the perfect way to level match if you have one

amp per woofer or one amp per set of woofers.

Testing with dummy loads rather than subwoofers, is a

more accurate way of finding maximum amplifier

output. Subwoofers have a nominal (Varying)

impedance or resistance, so your results could vary.

6. BRAND SELECTION

Here's another Short and sweet chapter, but by no

means unimportant.

There are different types of car stereo manufacturers.

Some are groups of investors, less interested in

product engineering, and more interested in profit

margins. Some are Audiophiles, truly concerned with

the quality of their products, and there are companies

everywhere in between. How can you differentiate?

Secret:

It probably takes a lot of experience to spot an

investment outfit. Look for tech support with no clue.

Look for a lot of chrome.

Look for product that looks eerily similar to big name

products. Look for almost naked women in their ads.

When you buy from the big names, your going to get

better engineering and expertise. This translates to

better

sounding products that last. When you buy from a

group of investors, you get a flashy product that might

not perform well, but for a great price!

There is a small number of companies still making

their stuff by hand. Your gonna pay a premium for this

stuff but it should be worth it. Great tech support.

Great products and your helping the little guys. I try to

find USA made stuff but its just about impossible

today.

Buy from an authorized dealer!

You won't understand the value of a warranty until

you need it. Let me tell you, I just bought a $2000

dollar piano from the wrong seller. No warranty but a

good price. This piano arrived broken. Selller won't

help. I can't fix it. It will cost me more to have it

repaired than a new one would have. I've learned that

when you invest more than you can stand to give

away, get a warranty or some kinda protection. Spend

that 25% more, and in return, you will get good tech

support and protection against defects.

#5 . WOOFER EFFICIENCY

The output of your system is not just determined by

that big 1000 watts logo on your subwoofers, or that

super big amp. Some subwoofers are actually built to

give you more bass in certain frequency ranges, and

some just waste a lot of it. Using this information can

help you build the best subwoofer system for your

tastes.

Secret:

Some subwoofers are merely heaters!!!

An awful trend has developed and the blood is on a lot

of hands. Stereo consumers love to see huge numbers

on amps and speakers. So the industry has obliged

with massive subwoofers designed to create and

dissipate heat, and amps with huge output or hugely

exaggerated output. There is no regulation of car

stereo specifications, only voluntary compliance, so a

manufacturer can claim anything. The reality is, a

subwoofer that might accept that huge 1000+ watts

from your amp, but instead of producing a fair amount

of sound pressure, it turns it into heat. It takes less

engineering prowess to build a subwoofer with more

copper in the voice coil and more venting, than it does

to build it with extended excursion and low distortion.

Early car subwoofers were derived from pro-sound

woofers. These have low moving mass and high

magnetic strength. This is the key to efficiency.

Unfortunately, if you find a set of club speakers and

put them in your car, expect the enclosure to be pretty

big. This is not the key to super low bass. The key here

is high magnetic strength, higher moving mass and

extended excursion. A woofer diaphragm with more

weight will have a lower resonant frequency and will

produce low frequencies better.

Now efficiency can be defined by what frequencies

you desire. A 6 inch mid-bass will not be efficient at

producing 40 hertz and a subwoofer will not be

efficient at 5 thousand hertz. So when you think about

efficiency, think about how much output you will get in

the range you desire. High moving mass = efficient at

low frequencies. Low moving mass = efficiency at high

frequencies.

#4 . ENCLOSURE EFFICIENCY

How do those competition cars hit such high numbers

with only one woofer?

Most of the answer lies in the box design. You CAN add

over 10 decibels of output with these methods.

Subwoofer box efficiency comes from a few things.

Secret:

Tuning frequency

Finding the best tuning frequency for your

competition enclosure takes a lot of work. First you

have to plot your cabin gain. How much gain does the

interior of your add to low frequencies? How much

gain does your subwoofer enclosure give you? Sum the

gain from the car and the box looking for the

frequency with the biggest numbers and you have it.

Port size

Subwoofers love to load with their environment and

their ports, which in turn load with the environment.

The best way for a woofer too see its port is by making

it big. Sounds like common sense right. When you

increase the surface area of your port, you increase the

efficiency of your enclosure. Having a small port is like

asking a small woofer to cycle at many inches of

excursion. This makes for unhappy woofers as well as

unhappy ports. This is why there are big woofers. They

are more efficient and need to throw a fraction of the

distance. When you make a port as big as you can, you

are increasing its capacity to move air. more air means

more pressure. Keep in mind, larger ports can get

really long.

Similar to porting and polishing an intake for a car,

make sure your port walls are smooth.

And here's two more efficiency secrets. Port bends

decrease enclosure efficiency. If you must bend, make

them smooth. Also, port width to height ratio should

be close. this means a 6 inches wide and six inches tall

(square) opening is ideal compared to a 3 x 12. Same

surface area but much more port wall surface area

decreases efficiency. The most efficient port will be

round, as big as you can make it,

Enclosure size

Why do club speakers kick so hard? Why does my

woofers manual say to put it in a small 1 cubic foot

enclosure?

Secret:

Big enclosure, Big output.

As previously mentioned, early car subwoofers were

pro-sound drivers. Enclosures were huge, and so was

efficiency. Your car woofer might only need 1 cubic

foot to perform says the manufacturer, because they

figure space is at a premium. A car is significantly

smaller than a club where enclosure size is rarely a

consideration.

At a certain box volume, a subwoofer enclosure will

begin to exhibit a high q. This means that its output

will begin to raise in a narrow band of frequencies at its

box resonance, as box volume raises. Let's say your

subwoofer system response is flat in 3 feet ported. If

you jump to 4 feet and keep the same subwoofer and

tuning, you will begin adding gain, like I said, in a

narrow band at the box resonance. This is called

�€ï¿½boomy�€ï¿½ by some, and is undesirable for sq, but

perfect for spl. Up to a point, increasing enclosure

volume will increase but narrow this band of

frequencies until it matches box tuning frequency. You

can dial in as little or as much gain as you want up to a

point. I have seen designs with over 15 decibels of

gain!!! Playing with enclosure modeling software, you

can find the perfect enclosure volume / gain ratio.

.

#3 . ENCLOSURE CONSTRUCTION

What should I build it out of? Does shape matter?

The construction of your enclosure is as important as

subwoofer selection, amplifier selection and

everything else.

Secret:

Port placement (previously discussed and elaborated)

Can I place my ports anywhere?

Lets explore this one plane idea further. I suggested

that your woofers and ports all be there. Why? Because

of phase. Because a port is an addition to the radiating

surface of your woofers. Porting an enclosure is like

adding another small woofer. You want all your bass

notes to reach your ears at the same time right? It

doesn't matter if it comes from ports or actual woofers,

this sound pressure needs to be in timing/phase or it

will not provide proper impact. As it turns out, you can

only achieve proper port function if it is on the same

plane as the woofer because they work together.

Placing the port and woofer on different planes

reduces their coupling, always reducing output and or

accuracy. Never run ports through your rear deck or

rear seats unless you have a single-reflex bandpass.

Ports should be at least its diameter from the rear wall

and sides of box, no bends, very smooth and with

flared ends. This section is as good as gold. USE THIS

INFO!!!

Enclosure seal

A subwoofer system can create plenty of pressure, and

if it is lost through a leaky enclosure, your output will

suffer. Your woofers output needs to radiate from two

places, the woofers cone, and the tuned port. A tuned

port will increase output within a given range of

frequencies, but a hole in the enclosure acts like a high

pass filter, at a very high frequency, eliminating your

bass!

Enclosure rigidity

A subwoofer can be a powerful device. In an enclosure,

it pressurizes and rarifies air. This can be compromised

by a flimsy enclosure. A subwoofer system needs to be

rigid so that the sound pressure it creates is not

undermined by changing enclosure volumes.

Build your enclosure out of the thickest wood you can.

3/4 inch MDF is usually a good starting point.

MDF will be a little stronger and damped but will be

prone to water damage. 1 inch wood is expensive but

could be your best choice for a real competition

system. In either case, here are some construction

secrets.

Never make any length more than double any other

length. Woofers don't like this

Never make your enclosure perfectly square.

Subwoofers don't like this either. It can cause

undesirable variations in your frequency response.

Brace your walls. Add a 2x4or a slice of your sheet

across the two largest panels. We don't want these

large panels to flex.

Pre-drill holes and countersink.

If you pre-drill your screw holes, there will be a

minimal chance of splitting the wood. Particleboard is

susceptible to this but MDF even moreso. Countersink

your screw heads to make a nice clean finish that will

accept upholstering much nicer.

Screws should be spaced about 10 inches apart for

good strength.

Adhesives.

I like to use a good construction adhesive for my

enclosures. The great thing about these ugly brown

tubes is that they add strength, even stronger than the

wood itself, plus they seal the box as they glue. Spread

a bead across all joints after you have drilled holes and

countersinks. Don't miss a spot or your box will leak air.

Alternatively, You can use wood glue and this is

common but you will need to run a bead of pure

silicone inside the box on all seams. This method

requires a little more work and will not be as strong.

The difference between construction adhesive and

wood glue is how hard it dries. Wood glue dries so hard

it will snap under pressure. Construction adhesive will

not.

Sealant.

I'm not talking about silicone this time. I'm talking

about making your Enclosure waterproof. This will

extend the life of your enclosure exponentially.

Particleboard and especially MDF don't like water. MDF

is actually a paper product. Both of these will swell and

disintegrate if exposed.

I always paint mine. Ask your local home store paint

department what they have that's waterproof. Buy

whats in your budget. You will probably be covering

your enclosure with carpet or vinyl anyway, so color is

of no importance. You can use a clear water seal, or

even a paint or primer.

A premium method of sealing your enclosure that will

be cosmetic at the same time is bed-liner. You can pick

some up at the auto parts store or you can have it

professionally done. The results from the pro's will be

much nicer looking but both do a great job of sealing

and protecting your enclosure.

Screws

I use 1.5 inch black coarse thread drywall screws for

my enclosures when I use 3/4 inch wood. This assures

the perfect grab on both pieces. The finish on the black

screws assures they won't come loose. They are strong,

economical, and easy to find.

Your subwoofer might require something more

serious. I will usually make the face of my enclosure

double thick and use extra long and thick screws. Don't

forget to pre-drill holes for your screws that are just

smaller than the diameter of your screws minus the

threads. This will hold a heavy subwoofer. If you can,

find some bolts and spiked T-nuts. This is a serious

approach for the most demanding applications.

#2 . USING DAMPING MATERIAL

(POLYESTER / WOOL / FIBERGLASS)

What is this polyester (or other) filling and what is it

supposed to do? Why have I seen it in Professionally

built enclosures? Can it really make my subwoofer

enclosure effectively bigger?

Polyester fill comes from the arts and crafts and pillow

manufacturing world. It is used to make stuffed dolls

and fake snow. It is claimed to effectively make a

speaker enclosure seem up to about 30% larger. It will

supposedly take a system with a high q (above .7) and

reduce it. This is exactly what would happen if you

made the enclosure bigger. So, add polyester fill and

reduce Q, and similarly, add enclosure volume and

reduce Q. Additionally, this fill can reduce in box

reflections and make your sub sytem sound cleaner.

Guess what people? As it turns out, what we once

thought was a great way to effectively increase box

size, is really A GREAT WAY TO EFFECTIVELY DECREASE

WOOFER SIZE!!! What this fill is actually doing is taking

our boomy box response and flattening it. Our low

bass output is already reduced because the box is too

small. We add some fill, and boom, now we've also

reduced our upper bass to make it flat. We have now

reduced our woofers total output potential by several

db's!!! The exact same effect as using a smaller

woofer!!!

Secret:

Don't add fill to your enclosure because its too small.

Save the expense of a bigger amplifier, fill, and the

price of that large woofer. Buy a woofer one size down

and give it the space it deserves. This will make for a

happy woofer, a less complicated build and be less

expensive. Additionally, if you are concerned about

reflections, do what I do. Grab yourself a new or used

piece of convoluted egg-crate style foam mattress pad.

Apply it on three inside walls with spray glue, so that

no two facing walls are uncovered. Throw a few staples

in the edges. This is the perfect way to add a little extra

accuracy to your subwoofer system.

#1 . SYSTEM MAINTAINENCE / LISTENING

Your subwoofer system, if properly maintained, can

last many years. This chapter Shows you ways to keep

your system in tip-top shape.

Audio equipment always has a desired operating

temperature range. You can usually find specifics in

your products owners manual. Typically, a car amp will

work in temperatures below freezing, and up to 125

degrees plus. A car amplifier will have protection

against overheating by way of a thermally activated

internal switch attached to its aluminum case. An overdriven

or underfed amplifier will overheat easily. Keep

your amps cool and unobstructed.

Your woofers doubtfully have any such protection.

This means you might overheat your woofers and

cause them to fail without warning.

What causes woofers to fail? Well, not just heat, but

cold too. A subwoofer with a synthetic rubber surround

can fail in extreme cold. Below 32 degrees, the soft

rubber surround on your woofer will turn hard like

plastic, and when driven with enough power, will

crack into pieces. This is also true with foam

surrounds. Treated cloth surrounds, although rare in

car audio are less affected by temperatures.

Secret:

Turn the volume up gradually, over several minutes in

cold weather. All of your equipment will thank you and

your woofer surrounds will have time to heat and

soften by way of internal friction.

Check connections.

As you drive, any number of connections can vibrate

loose. It is a good idea to go over your system checking

for this every once in a while. A bad connection can

cause low voltage, amp failure, burnt and melted fuseholders

and more.

Check your battery.

A bad battery can cause fouled battery terminals. This

corrosion, if left to spread can get in between your

battery terminals and your battery posts causing a bad

connection. Keep these connections clean with a

solution of water mixed with baking soda and cover

connections with a corrosion preventing spray

available at your neighborhood auto parts store. If

corrosion is a persistent issue, replace your battery,

maybe even with a sealed, maintenance free model.

Check for corrosion on your amp terminals and wires.

If you find white/green dust on any of your

connections, you have corrosion. This corrosion can

creep its way through an entire length of power cable

reducing its effective ability to supply current. This is

usually caused by wet carpet, cheap cables or a bad

connection.

Treat your system right.

This is important advice. Heat kills subwoofers. Heat

rises with time. This means, you can play your system

quite loud for a short burst without harming it

electrically, but if you play your system for extended

periods of time, heat rises, and glue starts to burn and

melt. These adhesives hold your woofers parts

together, specifically the voice coil wire. If this long,

thin, spun coil of metal falls apart, your subwoofer has

failed. It is now blown. This means, take a break every

few minutes of loud playing. Give your system a

chance to cool down. Keep in mind, your subwoofer is

not only an electrical device but also a mechanical one.

This means overpowering can not only cause it to

blow, but also to rip apart at any number of places.

Most typically, the voice coil will smack the back plate

and destroy it. Also, the woofer cone may come

detached from the voice coil former and often times,

the spider will rip apart from the coil, cone apex. Be

aware of noises coming from your subwoofer system

other than bass!!!

This brings me to the best maintenance tip.

Effective listening.

This means listening to music and distortion. We all

know what music is, although your parents probably

would argue your views. But lets explore distortion,

what it is and how to hear it. This sounds a bit ludicrous

but the truth is, there are several types of distortion.

You may not even know your system is distorting

because of your limited understanding of the

definition of distortion. Distortion in music is defined

as sound reproduced with flaws. This could be a

tonality difference. This could be a change in

dynamics. This could also be a change in harmonics.

Distortion as you probably know it is the harmonic

type. This is a great sign of a subwoofer system under

stress but before this becomes apparent, there is

another clue. As mentioned before, a change in

dynamics is distortion. Listen at low volumes and

notice the volume difference between loud and soft

notes. When you push your system to its limits, this

ratio will change and soft bass will become similarly

loud as the loud notes. This is a sign of compression.

The same effect they use on studio vocals so you can

hear every detail. You too, are trying to hear every bass

detail but you are stressing your system pushing it to

failure. No amp likes to clip, and no woofer likes

compression. This compression causes a lot of heat.

Heat kills Speakers.

Tonality Distortion.

Your favorite CD was created with a specific tonality in

mind. This sound is the vision of the artists and

recording engineers. Your goal is to play back this

recording as they intended it to sound. This is part of

their artistry, just like the notes they strum on their

guitars. Of course you are free to adjust the tonality as

you wish with your EQ, but in reality this is distortion.

Although nearly impossible, especially in a car,

recreating the recording as it was intended to be heard

is a beautiful thing.

Harmonic distortion.

This is the best and the worst distortion at the same

time. Have you ever heard of Vacuum Tubes? These are

classic amplification devices that when over-driven,

add desirable harmonics to your sound.

On the contrary, not all harmonics are desirable. The

harmonics created by a clipping amplifier or woofer

cone break-up. This hard to listen to. The best way to

keep undesirable harmonics from your system, is to

overbuild your system, with great quality products.

You will hear this distortion as an addition to the

sound you already hearing. If your speakers start to

make ugly additions to your music, you are most likely

experiencing harmonic distortion and this is a good

sign to turn the volume down.

System detailing.

To keep your system beautiful and ready for showing,

you'll want to follow your manufacturers suggestions

for cleaning. Of course never use harsh or abrasive

cleaners. Because this is a book of "secrets", I'll give

you a personal secret I don't share.

I use furniture polish in the yellow spray can to make

my plastic cone and rubber surround woofers shine

beautifully. Its not as greasy and shiny as dash spray.

Looks perfect, is supposed to have anti-dust properties

plus it smells lemon fresh, my favorite flavor. Check

with your woofer manufacturer to see if this would

void your warranty. Never use paper towels on your

equipment because they leave paper behind especially

on rough woofer cones. Some rough paper woofer

cones are especially hard to clean. I've found what

works best is a small hand towel dusting.

Keep some cotton swabs and microfiber cloths handy

to detail your amps. I have never used more than a nice

cloth to clean my amps. If you do this often and treat

them right you will never have to use a cleaner.

This e book is not perfect. but like I said at the beginning of the thread it's a good thing for the noobs.