Hello all. I am new to the forum, and a new driver, but I am now ready to put a system in my car. I am pretty familiar with home audio, but I do not know a whole lot about car audio since I haven't been driving for very long. I just have some general questions to clear some stuff up.
--Do aftermarket head units (stereo decks, CD players) generally have crossovers built into them?
--I am aware that a home audio subwoofer can be tuned/calibrated. Can the same be done for a car audio subwoofer? If so, how?
--I have heard of people having an amplifier for their speakers...what advantage does this have?
--Is it common to have ported enclosures in cars?
--What is sound damping, and what does it do? I have heard of ported enclosures being "lined" and sealed enclosures being "stuffed".
--Since the air pressure inside a subwoofer enclosure is higher than outside, how can I determine how low of frequency response my sub(s) are giving me?
--Generally, what kind of wires are used from the car battery to the amp, and is there a fuse required?
--Generally, what kind of wires are used from the amp to the sub(s)?
--Sometimes, there are little knobs on car audio amps. What are these knobs for? Can they aid in calibrating/tuning the subwoofers?
--I know in home audio, you can make it virtually impossible to blow your subwoofers by installing a rumble filter on the amp...is there a way to eliminate (or greatly reduce) the possibility of blowing your car audio subwoofers?
Sorry for so many questions. If you cannot answer ALL of these questions, that is fine. Just please answer what you can!
Any help appreciated!
--Thanks
--Do aftermarket head units (stereo decks, CD players) generally have crossovers built into them?
--I am aware that a home audio subwoofer can be tuned/calibrated. Can the same be done for a car audio subwoofer? If so, how?
--I have heard of people having an amplifier for their speakers...what advantage does this have?
--Is it common to have ported enclosures in cars?
--What is sound damping, and what does it do? I have heard of ported enclosures being "lined" and sealed enclosures being "stuffed".
--Since the air pressure inside a subwoofer enclosure is higher than outside, how can I determine how low of frequency response my sub(s) are giving me?
--Generally, what kind of wires are used from the car battery to the amp, and is there a fuse required?
--Generally, what kind of wires are used from the amp to the sub(s)?
--Sometimes, there are little knobs on car audio amps. What are these knobs for? Can they aid in calibrating/tuning the subwoofers?
--I know in home audio, you can make it virtually impossible to blow your subwoofers by installing a rumble filter on the amp...is there a way to eliminate (or greatly reduce) the possibility of blowing your car audio subwoofers?
Sorry for so many questions. If you cannot answer ALL of these questions, that is fine. Just please answer what you can!
Any help appreciated!
--Thanks
Disregard my last posts!
After some research, I answered a few of my own questions. I have some left though. Please help answer what you can!
--Do aftermarket head units (stereo decks, CD players) generally have crossovers built into them?
--What is the advantage of having an amplifier for your speakers
--Is it common to have ported enclosures in cars?
--What exactly does sound dampening do? Is it spelled damping dampening? I have heard both terms.
--Sometimes, there are little knobs on car audio amps. What are these knobs for?
--Is there a way to eliminate (or greatly reduce) the possibility of blowing your car audio subwoofers?
--How many discrete channels do head units usually output? I know they usually output 4 channels, but is it a stereo signal?
Any help appreciated!
--Thanks
After some research, I answered a few of my own questions. I have some left though. Please help answer what you can!
--Do aftermarket head units (stereo decks, CD players) generally have crossovers built into them?
--What is the advantage of having an amplifier for your speakers
--Is it common to have ported enclosures in cars?
--What exactly does sound dampening do? Is it spelled damping dampening? I have heard both terms.
--Sometimes, there are little knobs on car audio amps. What are these knobs for?
--Is there a way to eliminate (or greatly reduce) the possibility of blowing your car audio subwoofers?
--How many discrete channels do head units usually output? I know they usually output 4 channels, but is it a stereo signal?
Any help appreciated!
--Thanks
--Do aftermarket head units (stereo decks, CD players) generally have crossovers built into them?
Most of the mid level and higher ones do, some have 3-way (or even 4-way) crossovers built in, powerful enough to run a fully active system by themselves (with enough amps)
--What is the advantage of having an amplifier for your speakers
More output before distortion
--Is it common to have ported enclosures in cars?
Unfortunately, yes
--What exactly does sound dampening do? Is it spelled damping dampening? I have heard both terms.
It's referred to as damping and dampening, they're pretty interchangeable. Anyway, it has multiple uses depending on where you put it. When placed on the rear deck or trunk lid it reduces rattles. When placed on the doors it's used to seal up the baffle for the front speakers to reduce cancellation and increase midbass response. When placed basically anywhere else it's used to reduce road noise.
--Sometimes, there are little knobs on car audio amps. What are these knobs for?
Gain, EQ (frequency and/or boost level), and crossover frequency are the most common
--Is there a way to eliminate (or greatly reduce) the possibility of blowing your car audio subwoofers?
Yes, keep your amp out of clipping and listen to your subs, if they start distorting then turn the volume down, that's the best way to save them. Also, if they're ported then using a subsonic filter set about 5Hz below the box's tuning frequency is a very good idea (if it's tuned above 30Hz, since frequencies below ~30Hz are pretty rare).
--How many discrete channels do head units usually output? I know they usually output 4 channels, but is it a stereo signal?
2, car audio is only stereo, the 2 channels are just mirrored on the back. There is a fade control to adjust the relative output of the front/back, but they're still playing the same thing.
Most of the mid level and higher ones do, some have 3-way (or even 4-way) crossovers built in, powerful enough to run a fully active system by themselves (with enough amps)
--What is the advantage of having an amplifier for your speakers
More output before distortion
--Is it common to have ported enclosures in cars?
Unfortunately, yes
--What exactly does sound dampening do? Is it spelled damping dampening? I have heard both terms.
It's referred to as damping and dampening, they're pretty interchangeable. Anyway, it has multiple uses depending on where you put it. When placed on the rear deck or trunk lid it reduces rattles. When placed on the doors it's used to seal up the baffle for the front speakers to reduce cancellation and increase midbass response. When placed basically anywhere else it's used to reduce road noise.
--Sometimes, there are little knobs on car audio amps. What are these knobs for?
Gain, EQ (frequency and/or boost level), and crossover frequency are the most common
--Is there a way to eliminate (or greatly reduce) the possibility of blowing your car audio subwoofers?
Yes, keep your amp out of clipping and listen to your subs, if they start distorting then turn the volume down, that's the best way to save them. Also, if they're ported then using a subsonic filter set about 5Hz below the box's tuning frequency is a very good idea (if it's tuned above 30Hz, since frequencies below ~30Hz are pretty rare).
--How many discrete channels do head units usually output? I know they usually output 4 channels, but is it a stereo signal?
2, car audio is only stereo, the 2 channels are just mirrored on the back. There is a fade control to adjust the relative output of the front/back, but they're still playing the same thing.
Thanks for the response.
--What's the difference in a 3-way and 4-way crossover?
--What do you mean by the amp "clipping"?
--I know what the tuning frequency is, but how can you tell what frequency your subs are actually producing?
--Where can you get a subsonic filter, and where are they generally installed? Sounds like they are the same thing as a rumble filter for home audio.
--How do you tune/calibrate your subwoofers and speakers?
--You were talking about the crossover knob on the amp...this cannot control the frequencies that are sent to the speakers, can it?
--How do you know what to set your crossover at on the amp and on the stereo deck?
Appreciate it!
--What's the difference in a 3-way and 4-way crossover?
--What do you mean by the amp "clipping"?
--I know what the tuning frequency is, but how can you tell what frequency your subs are actually producing?
--Where can you get a subsonic filter, and where are they generally installed? Sounds like they are the same thing as a rumble filter for home audio.
--How do you tune/calibrate your subwoofers and speakers?
--You were talking about the crossover knob on the amp...this cannot control the frequencies that are sent to the speakers, can it?
--How do you know what to set your crossover at on the amp and on the stereo deck?
Appreciate it!
--What's the difference in a 3-way and 4-way crossover?
A 3-way has support for a highpass on one pair of channels, bandpass on another pair of channels, and lowpass on another pair of channels. Typically it highpasses the "front" outputs for use with a tweeter, bandpasses the "rear" outputs for use with a midbass, and lowpasses the "subwoofer" outputs for use with a sub. A 4-way crossover is the same but with another bandpass thrown in there for a midrange. The only headunit I know of with a 4-way crossover built in is that crazy Clarion (forgot the model). Several units have 3-way crossovers built in, Alpine, Pioneer, and Eclipse all offer their own.
--What do you mean by the amp "clipping"?
That's what happens when you try to push an amplifier beyond its limits. The top and bottom of the wave (which looks somewhat like a sine wave) get cut off. The first figure on this page has a nice graphical representation of the results of clipping.
--I know what the tuning frequency is, but how can you tell what frequency your subs are actually producing?
They're producing whatever they're being fed. There are several ways to check this, but the easiest would be to generate a frequency spectrum plot, which shows the frequency content of the song. There are several ways to get this, if you have a good mathematics program (matlab, maple, etc) you can just take the discrete fourier transform and plot the results.
--Where can you get a subsonic filter, and where are they generally installed? Sounds like they are the same thing as a rumble filter for home audio.
They are, but normally at a higher frequency. Most mono car amplifiers have them built in.
--How do you tune/calibrate your subwoofers and speakers?
By ear, unless you have access to an RTA and mic
--You were talking about the crossover knob on the amp...this cannot control the frequencies that are sent to the speakers, can it?
Yeah, it's an adjustable highpass or lowpass filter (highpass for the front speakers, lowpass for the sub)
--How do you know what to set your crossover at on the amp and on the stereo deck?
80Hz is a good starting point, but you have to adjust by ear from there.
A 3-way has support for a highpass on one pair of channels, bandpass on another pair of channels, and lowpass on another pair of channels. Typically it highpasses the "front" outputs for use with a tweeter, bandpasses the "rear" outputs for use with a midbass, and lowpasses the "subwoofer" outputs for use with a sub. A 4-way crossover is the same but with another bandpass thrown in there for a midrange. The only headunit I know of with a 4-way crossover built in is that crazy Clarion (forgot the model). Several units have 3-way crossovers built in, Alpine, Pioneer, and Eclipse all offer their own.
--What do you mean by the amp "clipping"?
That's what happens when you try to push an amplifier beyond its limits. The top and bottom of the wave (which looks somewhat like a sine wave) get cut off. The first figure on this page has a nice graphical representation of the results of clipping.
--I know what the tuning frequency is, but how can you tell what frequency your subs are actually producing?
They're producing whatever they're being fed. There are several ways to check this, but the easiest would be to generate a frequency spectrum plot, which shows the frequency content of the song. There are several ways to get this, if you have a good mathematics program (matlab, maple, etc) you can just take the discrete fourier transform and plot the results.
--Where can you get a subsonic filter, and where are they generally installed? Sounds like they are the same thing as a rumble filter for home audio.
They are, but normally at a higher frequency. Most mono car amplifiers have them built in.
--How do you tune/calibrate your subwoofers and speakers?
By ear, unless you have access to an RTA and mic
--You were talking about the crossover knob on the amp...this cannot control the frequencies that are sent to the speakers, can it?
Yeah, it's an adjustable highpass or lowpass filter (highpass for the front speakers, lowpass for the sub)
--How do you know what to set your crossover at on the amp and on the stereo deck?
80Hz is a good starting point, but you have to adjust by ear from there.
rocko1290 said:
The wavelengths the sub is reproducing are very very long, standing waves aren't an issue in this case so that's not something you have to worry about. The most it would do is help keep the box's panels from vibrating, but I doubt it would do much, and I highly doubt it would be audible, especially in a car.
You can use it on anything you want, but it's only really needed on a ported enclosure, and only on a ported enclosure that's tuned above ~30Hz.
The reason is because finding a signal that resides well below 30Hz in music is extremely rare (it's not rare in HT, movies can dig deep, but most people don't play movies in their car), and finding one that's powerful enough to hurt your speaker is even more rare. You only really need a SSF if your sub is tuned high enough where normal music is capable of causing it to unload (which happens ~1/2 octave below tuning), which makes it very easy to damage your sub. In other words, if you're tuned to 40Hz, the sub will begin unloading around 28Hz. A powerful 28Hz signal is relatively hard to find in music, but they are out there, so to be on the safe side you would want to set your SSF around 35Hz so by 28Hz, the signal has been attenuated enough that it won't cause damage from unloading. On the other hand, if you're tuned to 25Hz, the sub won't begin unloading until ~17Hz. Unless you go around playing 15Hz test tones everywhere, you won't have a problem, so you don't need a SSF.
A sealed sub doesn't unload, so there're no real worries there.
The reason is because finding a signal that resides well below 30Hz in music is extremely rare (it's not rare in HT, movies can dig deep, but most people don't play movies in their car), and finding one that's powerful enough to hurt your speaker is even more rare. You only really need a SSF if your sub is tuned high enough where normal music is capable of causing it to unload (which happens ~1/2 octave below tuning), which makes it very easy to damage your sub. In other words, if you're tuned to 40Hz, the sub will begin unloading around 28Hz. A powerful 28Hz signal is relatively hard to find in music, but they are out there, so to be on the safe side you would want to set your SSF around 35Hz so by 28Hz, the signal has been attenuated enough that it won't cause damage from unloading. On the other hand, if you're tuned to 25Hz, the sub won't begin unloading until ~17Hz. Unless you go around playing 15Hz test tones everywhere, you won't have a problem, so you don't need a SSF.
A sealed sub doesn't unload, so there're no real worries there.
Gotcha, thanks. Thanks for all your help man, you have been really helpful. What kind of amp would you reccomend? I'm probably gonna need a 600w at 2 ohm mono amp. I think I am going to have a ported enclosure so I shouldn't need a subsonic filter then.sr20dem0n said:
Now can you turn off the subsonic filter if you don't need it?
Oh--and 1 more thing--how can I add neon/ccfl lighting to my enclosure?
Most of the mainstream brands make decent mono amps that are built to run at 2ohm (Alpine, Kicker, etc).
A ported enclosure is what you should be using a SSF for, if it's tuned relatively high.
Some amps let you turn it off, others let you turn it to such a low frequency that it won't affect you
You could add neon if you want....but I have no idea why you would. Autozone and Pepboys sell neon bulbs that run off of 12v, you would just run them off of a relay so they turn on/off with either the switched 12v signal in the car or a manual switch that you could mount somewhere.
A ported enclosure is what you should be using a SSF for, if it's tuned relatively high.
Some amps let you turn it off, others let you turn it to such a low frequency that it won't affect you
You could add neon if you want....but I have no idea why you would. Autozone and Pepboys sell neon bulbs that run off of 12v, you would just run them off of a relay so they turn on/off with either the switched 12v signal in the car or a manual switch that you could mount somewhere.
Well I wanted to try to get a relatively low tune with the ported enclosure, like 25-30 hz. Then I shouldn't need a SSF. If my tune ends up being higher than that then I'll go ahead and buy an amp with a SSF (who knows, I might end up getting an amp with an SSF anyway).sr20dem0n said:
What do you think about JBL and JL Audio amps?
You don't like neon in cars? I'm young so I like it now, but I probably won't eventually...I am a little confused on how I would wire up the neon, but I think my step-dad can help me with that. Is there a sound module that you can buy that will allow the neon to pulsate to the music?
Why do you say a sealed subwoofer cannot unload? Generally, the sealed subs will have a higher tuning frequency than the ported...so let's say you had a sealed subwoofer tuned at 45hz...if it was fed a 30hz signal, why wouldn't it unload?
1 - Sounds good
2 - They're nice, I'd take JL over JBL, but I'd take many other brands over either
3 - I believe you can buy neon that pulses with the music from Autozone and Pep Boys, you'd just want to cut off the cig lighter adaptor (unless it's what controls the pulsing, in which case you'd want to disect it), wire it to the output of a relay, and wire the power for the relay to the battery and control for the relay to the switched 12v line or to a switch which is wired to power
4 - A sealed sub doesn't have a tuning frequency because there's no port. With no port and no tuning frequency, it can't unload.
2 - They're nice, I'd take JL over JBL, but I'd take many other brands over either
3 - I believe you can buy neon that pulses with the music from Autozone and Pep Boys, you'd just want to cut off the cig lighter adaptor (unless it's what controls the pulsing, in which case you'd want to disect it), wire it to the output of a relay, and wire the power for the relay to the battery and control for the relay to the switched 12v line or to a switch which is wired to power
4 - A sealed sub doesn't have a tuning frequency because there's no port. With no port and no tuning frequency, it can't unload.
Thanks. What do you think about this amp? Is the SSF and the crossover fully adjustable on this amp?
http://www.cartoys.com/Default.cfm/p/MRPM650_Mono_Channel_ClassD_Amplifier/
http://www.cartoys.com/Default.cfm/p/MRPM650_Mono_Channel_ClassD_Amplifier/
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