by GlassWolf » Sat Jan 04, 2014 12:13 pm
plcrides wrote:I've always had jl amps,and man they cost a lot,but!!!!! i love them,last year i got some dc audio 15's and a dc audio 2000 watt amp and the amp has gain,sub sonic,and lpf the sub sonic didn't really do much
subsonic filters, as the name implies, are filtering signals below the range of human hearing. Their purpose is for ported enclosures. With a ported enclosure, you need to set the subsonic filter (ISF or infrasonic filter) to the frequency at which your enclosure's port is tuned. If you have ports tuned to 38Hz, set your ISF to 38Hz as well. This prevents the enclosure from allowing the subs to unload, and over-excurt, which will "blow" your subs. ISF isn't needed for a sealed box, and can be turned all the way down if you wish.
and when you went to adjust the lpf as soon as you would turn it up any!!! it would send the subs into a bah bah bah bah instead of boom boom boom,very weird,had to adjust settings on the HU.
for a 15" sub, your LPF should be set to about 50-55Hz, and no higher. 15" subs aren't designed to reproduce 80-120Hz or above, which are better left to smaller mid-bass drivers. If you want to keep the bass tight and responsive, set LPF to 50Hz, and "Q" or "slope" to 18 or 24dB/octave. Do NOT use both the head unit and amplifier crossovers together, as they will have a cumulative effect, giving a very steep Q, If the subs are distorting, also make sure the amp is getting enough current. JL slash-series amplifiers don't have as much of an issue with current due to the regulated power supply and regulated output, but nearly all other amplifiers are far more dependent on a stable current supply and input voltage rail. Also, don't turn your gain up beyond about 1/4 turn from it's lowest setting. You really should set the gain properly, instead of doing it by ear, though. See the FAQ section on this board for a guide to gain setting.
My JL's that i have 3 of them,have all these switches and dials and buttons lol and they really make a huge difference in sq. my question is I've read the manual a dozen times but i can't understand what all that means if anyone knows a jl audio amp say a 500/1 or a 1000/1 what does the center frequency do ? and the parametric eq bandwidth control do ?
and the infrasonic filter do ? ( in lamens terms please )
center frequency is the center-point for the parametric EQ. a parametric EQ lets you set three things:
1. the frequency (center freq.) to be equalized
2. the Q or slope (bandwidth): an EQ, like a crossover, isn't a brick wall. If you set a XO (crossover) or EQ at 1000Hz, it isn't only 1000Hz precisely that's affected. The slope (Q or bandwidth) is how gradually or sharply the cut or boost of that frequency returns to normal as you go up or down in frequency from that center point of 1KHz. An "octave" is half, or double the frequency of the starting point, so one octave below 1KHz is 500Hz, and one octave up would be 2KHz or 2000 Hz. The "Q" is measured in dB (decibels) per octave, and decibels are a measure of relative volume, SO... this leaves us with
3. cut or boost: how much the EQ will affect the sound curve.
result: you set the EQ for 1KHz, 12dB/octave Q, boost of say, 6dB. you'll get:
At 1KHz, you'll get a boost in volume in the sound curve of 6 decibels, and for every octave you move away from 1KHz, that boost in volume will drop 12 decibels until you've returned to [reference] or normal volume. That's how an EQ works. fixed frequency slider-type EQs just don't allow you to pick the exact frequency to adjust. They set those for you, typically 1 octave apart, and the Q is preset as well, so all you have control over is cut/boost at predetermined frequencies.
If you don't feel confident setting up an amp, go to a car stereo shop and let a professional do it for you.
i want to get a 3rd sub in the future and I've been looking at subs and now I'm like ok i need one with more adjustments then the dc.
thanks LC
now you're getting into an entirely difference can of worms, dealing with electrical loads, impedance balancing, series-parallel wiring, and so forth. Why do you think you need a third sub? Have you considered a different enclosure, or more power instead? Maybe better subs with a longer Xmax and better Bl curve? Talk to a professional who can help you make some of these decisions before diving into the deep end yourself.
[quote="plcrides"]I've always had jl amps,and man they cost a lot,but!!!!! i love them,last year i got some dc audio 15's and a dc audio 2000 watt amp and the amp has gain,sub sonic,and lpf the sub sonic didn't really do much[/quote]
subsonic filters, as the name implies, are filtering signals below the range of human hearing. Their purpose is for ported enclosures. With a ported enclosure, you need to set the subsonic filter (ISF or infrasonic filter) to the frequency at which your enclosure's port is tuned. If you have ports tuned to 38Hz, set your ISF to 38Hz as well. This prevents the enclosure from allowing the subs to unload, and over-excurt, which will "blow" your subs. ISF isn't needed for a sealed box, and can be turned all the way down if you wish.
[quote] and when you went to adjust the lpf as soon as you would turn it up any!!! it would send the subs into a bah bah bah bah instead of boom boom boom,very weird,had to adjust settings on the HU.[/quote]
for a 15" sub, your LPF should be set to about 50-55Hz, and no higher. 15" subs aren't designed to reproduce 80-120Hz or above, which are better left to smaller mid-bass drivers. If you want to keep the bass tight and responsive, set LPF to 50Hz, and "Q" or "slope" to 18 or 24dB/octave. Do NOT use both the head unit and amplifier crossovers together, as they will have a cumulative effect, giving a very steep Q, If the subs are distorting, also make sure the amp is getting enough current. JL slash-series amplifiers don't have as much of an issue with current due to the regulated power supply and regulated output, but nearly all other amplifiers are far more dependent on a stable current supply and input voltage rail. Also, don't turn your gain up beyond about 1/4 turn from it's lowest setting. You really should set the gain properly, instead of doing it by ear, though. See the FAQ section on this board for a guide to gain setting.
[quote]My JL's that i have 3 of them,have all these switches and dials and buttons lol and they really make a huge difference in sq. my question is I've read the manual a dozen times but i can't understand what all that means if anyone knows a jl audio amp say a 500/1 or a 1000/1 what does the center frequency do ? and the parametric eq bandwidth control do ?
and the infrasonic filter do ? ( in lamens terms please ) [/quote]
center frequency is the center-point for the parametric EQ. a parametric EQ lets you set three things:
1. the frequency (center freq.) to be equalized
2. the Q or slope (bandwidth): an EQ, like a crossover, isn't a brick wall. If you set a XO (crossover) or EQ at 1000Hz, it isn't only 1000Hz precisely that's affected. The slope (Q or bandwidth) is how gradually or sharply the cut or boost of that frequency returns to normal as you go up or down in frequency from that center point of 1KHz. An "octave" is half, or double the frequency of the starting point, so one octave below 1KHz is 500Hz, and one octave up would be 2KHz or 2000 Hz. The "Q" is measured in dB (decibels) per octave, and decibels are a measure of relative volume, SO... this leaves us with
3. cut or boost: how much the EQ will affect the sound curve.
result: you set the EQ for 1KHz, 12dB/octave Q, boost of say, 6dB. you'll get:
At 1KHz, you'll get a boost in volume in the sound curve of 6 decibels, and for every octave you move away from 1KHz, that boost in volume will drop 12 decibels until you've returned to [reference] or normal volume. That's how an EQ works. fixed frequency slider-type EQs just don't allow you to pick the exact frequency to adjust. They set those for you, typically 1 octave apart, and the Q is preset as well, so all you have control over is cut/boost at predetermined frequencies.
If you don't feel confident setting up an amp, go to a car stereo shop and let a professional do it for you.
[quote]i want to get a 3rd sub in the future and I've been looking at subs and now I'm like ok i need one with more adjustments then the dc.
thanks LC[/quote]
now you're getting into an entirely difference can of worms, dealing with electrical loads, impedance balancing, series-parallel wiring, and so forth. Why do you think you need a third sub? Have you considered a different enclosure, or more power instead? Maybe better subs with a longer Xmax and better Bl curve? Talk to a professional who can help you make some of these decisions before diving into the deep end yourself.