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| Q: |
Q: I like the radio that came with my car, but it doesn't play loud enough. Do I have to change the radio to get good sound? |
| A: |
A: No, you don't have to change the radio in your vehicle. In fact, for the money spent, the best investment you could make would be a Rockford Fosgate amplifier and speakers. Our RF series amplifiers have special input connections that are made to work with your factory radio, and the Punch & Power series amplifiers will also work with the addition of a Connecting Punch adapter (model #'s RP9360, RP9362, or RP9364). |
| Q: |
Q: I have a new Rockford Fosgate RFX source unit, but the backlighting behind the buttons doesn't work. What
should I do? |
| A: |
A: All RFX (except RFX-8115) decks have a separate wire for the backlighting. The wire is orange in color and must
be connected to a source of +12 volts to engage the backlighting of the deck. It can be connected to the radio
remote output "A" (light blue), if you prefer the backlighting on whenever the radio is on. If you prefer
backlighting only when the cars lights are on, you can connect the orange wire to the cars dashlight wire or parking
light wire. Just be sure the wire is a source of +12 volts. |
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| Q: |
Q: My new Punch Power Series amplifier is capable of a 24 dB per octave slope on the crossover. Why would I want
to use 24 dB per octave instead of 12 dB per octave? |
| A: |
A: When we speak of "slope" regarding crossover networks, what we are referring to is the amount of
attenuation the crossover has above or below the crossover frequency. If we say we have a crossover of 80 hertz
"low pass", that means that frequencies above 80 hertz are attenuated (reduced in level). However, that
doesn't mean that everything above 80 hertz is completely eliminated. The slope of the crossover determines how
quickly the information above 80 hertz is attenuated. The steeper the slope (higher number), the faster the
information is attenuated.
So, it sounds like we would always want to use a steeper slope right? There are times when it can be an advantage.
For instance, if we use a steeper slope on the woofers in a system, we will attenuate the higher frequencies faster.
This can give us more "bass up front" in a system. Likewise, using a steeper slope in a high pass
application can give speakers higher power handling by removing the low frequencies faster. The Fanatic Component
Systems use at least 18 dB per octave slopes for high pass on the tweeters.
Steeper slopes do add complexity to the crossover however, and depending on the system configuration, may have no
real sonic advantage over 6 or 12 dB slopes. |
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| Q: |
Q: How do I bridge an older 2 channel Rockford Fosgate amplifier that has a wire harness for the speakers? |
| A: |
A: Use the orange wire for (+) and the brown wire for (-). The yellow and black
wires are not used. |
| Q: |
Q: How do I bridge a newer 2 channel Rockford Fosgate amplifier that has terminal connections for the speakers? |
| A: |
A: All newer 2 channel Rockford Fosgate amplifiers except Power Series use the (left +) for
(+) and the (right -) for (-). The (left -) and the (right +) are not
used. |
| Q: |
Q: What's the lowest impedance I can run on a Rockford Fosgate amplifier? |
| A: |
A: The RF, Punch & Punch Power 250.1, 250.2 & 500.2 amplifiers are all rated for use to 2 ohms per channel
or 4 ohms when bridged. The Power 50.1 & 50.2 amplifiers are rated for use to 1 ohm per channel or 2 ohms when
bridged, although many of our customers use the 50.1 & 50.2 at 0.5 ohm per channel or 1 ohm when bridged. |
| Q: |
Q: I heard that "high current" watts are better than regular watts. Is that true? |
| A: |
A: Watts are watts, no matter how you slice them! Our high current amplifiers make the most power at very low
impedances. Our other amplifiers make the most power around 2 ohms per channel. However, 100 watts from a
"regular" amplifier is the same as 100 watts from a "high current" amplifier. Two amplifiers
may make maximum power at different impedances, but power is power. On the other hand, it is kind of cool to say
you have a "50 watt" amplifier that puts out about 450 watts! The Punch Power 50.1 does just that.
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| Q: |
Q: I have 200 watt speakers. Do I need a 200 watt amplifier to drive them? |
| A: |
A: No. The 200 watt rating is how much power the speakers can accept, not how much they must have. Even a 200 watt speaker can sound great with just a few watts applied.
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| Q: |
Q: How do I know which woofers to choose for my car? |
| A: |
A: That's a tough question. We will need some information before we can decide. First, do you have a woofer
amplifier already? If yes, how much power does it produce? If it's a small amplifier we won't have any power
handling concerns. If it's a large amplifier, that may narrow the choices somewhat, as we want to choose a woofer
that can handle the power the amplifier produces.
Next, how much space are you willing to give up in the quest for bass? If you aren't willing to give up much space
you may have to stick to a single RFP or RFP-DVC woofer. Luckily, these woofers handle lots of power, so even a
single woofer can give you BIG bass. If you have lots of room, and are after ground pounding bass, I would go with
as many of the largest woofers you can fit. There is no substitute for cubic inches! Even a little amplifier can
gives you lots of bass if you have enough woofers. |
| Q: |
Q: I'm building a vented enclosure. Where should I install the vent? |
| A: |
A: Whenever possible, we recommend that the vent be installed on the same "side" of the enclosure as the
woofer(s). One important thing to remember is to not block the output of the vent. Try to keep all surrounding
objects a vent diameter away from both ends of the vent. This also applies inside the enclosure as well.
Obstructing the output of the vent may change the tuning frequency, which may be detrimental to performance. |
| Q: |
Q: What determines the best type (sealed, vented, single or dual reflex bandpass) of enclosure for a particular
woofer? |
| A: |
A: Generally speaking, there are some speaker specifications that lend a driver to one type of enclosure over
another, although many drivers are suited to more than one type of enclosure. These are generalizations and are NOT
cast in stone!! Woofers that perform best in sealed enclosures (or single reflex bandpass) usually have a lower FS,
slightly higher QTS and more X-max than woofers designed for vented (or dual reflex bandpass) enclosures.
There is also a formula to calculate what is called the "efficiency bandwidth product" of a particular
driver. The EBP of a woofer can be used as a guideline for the enclosure type. It is calculated with the formula:
EBP in the vicinity of 50 or lower indicates a sealed enclosure, while EBP of 100 or higher indicates a vented
enclosure. Again, these are suggestions only. |
| Q: |
Q: Where should I mount my new Fanatic Component speakers for best imaging? |
| A: |
A: When optimum imaging is the goal, the ideal situation would be to mount all the speakers on axis with your ears,
and with the path length difference from left to right kept to a minimum. This usually means mounting the speakers
in the kick panel area, with the mids & tweets as close together as possible. However, good imaging can still
be obtained by experimenting with tweeter placement, and using a factory location for the mids. The image will not
be as well focused or placed with the tweeter mounted away from the mid, but it may be a compromise that is
acceptable to you. |
| Q: |
Q: I want to install a pair of 15" woofers in my car that require a total of 5 cubic feet of internal volume.
I only want to give up 4 cubic feet. What can I do to make the 15's work? |
| A: |
A: If the space you have available is 4 cubic feet and the woofers require 5 cubic feet, I would consider using
woofer(s) that require less space. Building a 4 cubic foot enclosure that is optimum for two smaller woofers may
sound better than building an enclosure that is too small for the 15's. The key is to determine the space you have
available, and then choose the woofer(s) that are right for that space. |
| Q: |
Q: Does a woofer handle more power in a sealed or vented enclosure? |
| A: |
A: When we speak of power handling related to the enclosure, we are referring to mechanical power handling
(excursion). Assuming the same driver in two identical sized enclosures, one sealed and the other vented, the
following statements are true:
- Power handling at higher frequencies is very similar in both enclosures
- Power handing near vented enclosure FB (tuning freq.) is better in the vented enclosure
- Power handling at very low frequencies (below vented FB) is better in the sealed enclosure
It's difficult to give a definitive answer for the power handling question as the conditions vary widely. However,
the resonant mechanical system formed by the vent and the enclosure does, in most cases, increase power handling
greatly in the usable bass range. |
| Q: |
Q: I need to build a 1.0 cubic foot enclosure. How do I figure the volume? |
| A: |
A: The formula to figure volume of a rectangle or square is:
We want to calculate the interior volume, so make sure to use "inside" measurements in the formula. In other words, you want to measure the inside of the enclosure and not the outside. The inside of the enclosure is the space the woofer will "see", right? To do this simply take the outside measurement and subtract the wood or material thickness from all sides. For instance if you have an enclosure that is 12" wide and uses 0.75" thick wood, you would subtract 1.5" from 12", leaving 10.5". Do the subtraction for all dimensions of the enclosure.
Let's figure the volume for the following enclosure:
This enclosure uses 0.75" thick wood, so we must subtract 1.5" from each dimension, and use the
(inside) dimensions in our formula.
Width = 15" (outside) / 13.5" (inside)
Height = 14" (outside) / 12.5" (inside)
Depth = 12" (outside) / 10.5" (inside)
Remember the formula?
Plug in the dimensions:
Perform the multiplication:
Divide by 1728:
This enclosure has an internal volume of approximately 1 cubic foot!
Another popular shape enclosure is a wedge. This has an angled front or rear panel that is usually the same angle as the seat back. The enclosure is angled so as to take up less interior volume in the vehicle. It is very simple to calculate using the same formula as above. However, we have two depth measurements (we will call them D1 and D2) in this particular enclosure, so we must find the average depth of the enclosure and use that average in the formula.
Here's the enclosure:
This enclosure uses 0.75" thick wood, so we must
subtract 1.5" from each dimension, and use the
(inside) dimensions in our formula.
Width = 15" (outside) / 13.5" (inside)
Height = 14" (outside) / 12.5" (inside)
Depth 1 = 9" (outside) / 7.5" (inside)
Depth 2 = 15" (outside) / 13.5" (inside)
First we must find the average depth of the enclosure. 
The average depth of the enclosure is 10.5" (inside). Now we can plug 10.5" into our formula and figure the volume of the enclosure.
Remember the formula?
Plug in the dimensions:
Perform the multiplication:
Divide by 1728:
This enclosure also has an internal volume of approximately 1 cubic foot!
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| Q: |
Q: I'm installing a new Rockford Fosgate amplifier. Is it necessary to have a fuse at the battery? |
| A: |
A: Yes, it is absolutely necessary to have a fuse at the battery! That fuse will protect the amplifier's main power wire (and the car!) in case it shorts to the car chassis. It is acceptable to install the fuse that comes with the amplifier at the battery. It will then serve to protect the amplifier and the power wire.
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| Q: |
Q: I'm installing a Rockford Fosgate amplifier in my car. I know that I need to run the main power wire to the battery and that it needs to be fused. Do I have to run the amplifier ground wire to the battery as well? |
| A: |
A: The preferred method for grounding an amplifier would be to keep the ground wire as short as possible (assuming the vehicle allows this), and connect it to a clean bare metal point on the vehicle. Running the ground wire to the battery actually increases the chances for system noise. |
| Q: |
Q: I know that Rockford Fosgate amplifiers make much more power than advertised. How do I match your amplifiers to your speakers? |
| A: |
A: Our amplifiers do make more power than advertised, but our speakers can handle it. Simply match the amplifiers rated power to the speakers rated power and you will be fine.
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| Q: |
Q: How many speakers can I connect to a Rockford Fosgate amplifier? |
| A: |
A: Great question. Actually, there is no limit to the number of speakers our amplifiers can run. As long as the
overall impedance is kept within recommendations, everything will be great. So feel free to connect as many
speakers as you like, just mind the impedance! |
| Q: |
Q: I have four 4 ohm woofers and a Punch 2 channel amplifier. I want to bridge the amplifier. How do I make the
connections? |
| A: |
A: Since all Punch 2 channel amplifiers are 4 ohm stable when bridged, we recommend that you divide the woofers
into two pairs, connecting each individual pair of woofers in series. This essentially gives you two 8 ohm loads.
From that point you would connect the two 8 ohm pairs in parallel to achieve a 4 ohm load. See the diagram for
connection information. |
| Q: |
Q: I know that Rockford doesn't recommend running a Punch 2 channel amplifier below 4 ohms bridged. How do I use
the Punch DVC (dual voice coil) woofers on my amplifier? |
| A: |
A: The Punch DVC woofers are designed to extract maximum amplifier performance. As such, we are concerned with the
actual impedance of the system rather than the resistance. When a speaker is given a 4 ohm or 8 ohm number, it is
an approximation of the actual impedance. In most systems, the actual measured impedance will be higher than
calculated. So, a system that has a theoretical impedance of 2 ohms may actually be closer to 4 ohms! We have
constructed many enclosures and made actual impedance measurements of Punch DVC systems and found that they are
usually around 4 ohms in most cases.
The key is that we have taken the time to measure these systems and have found them to be safe. As long as the
measured impedance is around 4 ohms, a Punch 2 channel amplifier will work just great! |
| Q: |
Q: Can I wire three Rockford Fosgate woofers to a Rockford Fosgate amplifier? |
| A: |
A: Absolutely!! With our 4 ohm stable (when bridged) amplifiers, we recommend three 8 ohm woofers, all wired in
parallel and bridged to the amplifier. This theoretical 2.67 ohm load is actually very close to 4 ohms through the
usable bass range. Three Punch DVC woofers can also be wired in this fashion!
For our low impedance (50.1 & 50.2) and mono (250.1) amplifiers, three 4 ohm woofers in parallel will work
great. Theoretically a 1.3 ohm load, these systems are usually in the 2 ohm range. |
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| Q: |
Q: I have four Rockford Fosgate amplifiers in my car & my lights dim when the bass hits. Do I need a bigger alternator? |
| A: |
A: Most likely the answer is no. If you listen to music with the engine running, all that is necessary is a Punch Cap(s). The Punch Cap will store energy and deliver it when the system needs it. About 1 farad of capacitance per 1000 watts should take care of the dimming lights, and give you harder hitting bass as well. |
| Q: |
Q: What causes turn on / off pops and thumps and how can I get rid of them? |
| A: |
A: When a car audio system utilizes additional components such as amplifiers and processors, those devices are
turned on and off automatically with a signal from the source unit. Occasionally, those components may have built
in delays that turn them on and off at different intervals. This is especially common when mixing different brands
of components into a single system. These different turn on / off intervals may cause an audible pop or thump when
turning the system on or off. For example, if the amplifier in a system turns on before a crossover, the crossover
may send a small transient signal to the amplifier. Because the amplifier is already on, it amplifies the transient
signal causing the turn on noise.
There are different methods to cure a turn on noise, including devices that "delay" the turn on of the
amplifier until after the other components have come on and "settled down". These delay turn on devices
are available from most car audio accessory suppliers. To cure a noise at turn off the amplifier must shut off
before the other components in the system. To do this you must delay the turn off of the other components until
after the amplifier shuts off.
This sounds like a lot of work, and it can be frustrating to get rid of such noises. Fortunately, the geniuses at
Rockford Fosgate have come up with a method that eliminates both turn on AND off noises. This circuit is called
SMART ON (Sequentially Managed Accessory Remote Turn ON), and turns components on and off in sequential order. The
amplifier(s) in the system are the last component to turn on at system power up and the first to turn off at system
power down, eliminating noises. This ingenious circuit is included in each and every Rockford Fosgate source
unit! |
| Q: |
Q: Why does my amplifier distort when I turn its gain adjustments up? |
| A: |
A: Contrary to popular belief, those gain (input sensitivity) adjustments are not "volume" controls! The
reason those adjustments are there is to allow compatibility with different types of equipment. What they actually
do is set the amount of input voltage required to drive the amplifier to full power. Let's say we have an amplifier
that is capable of producing 50 watts. If those input adjustments were made correctly, the amplifier would produce
50 watts with the source unit volume at or near its maximum. If the input sensitivity is increased, the amplifier
may make 50 watts at a much lower position on the source unit volume control. If the volume on the source unit is
then increased, the amplifier begins to clip and produce distortion because it cannot produce any more than 50
watts. By increasing the sensitivity of the amplifier you also increase the chances for noise in the system. |
This FAQ was written by Mr. Jay Small, R.T.T.I. Instructor, Rockford Corporation.
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