brianG

YOUR POST? perhaps I am misunderstanding since I've been putting post up to help ppl since this site was first started..... welcome back me

There are really two types of Class D amplifiers. Analog-Controlled Class D: Switching amplifiers with an analog input signal and an analog control system. Normally some degree of feedback error correction is present. Digitally-Controlled Class D: Amplifiers with a digitally generated control that switches a power stage. No error control is present. Those that do have an error control can be shown to be topologically equivalent to an analog-controlled class D with a DAC in front. To make a very good full-range Class D amplifier, the switching frequency must be well above 40kHz. Also, the amplifier must be followed by a very good low-pass filter that will remove all of the switching noise without causing power loss, phase-shift, or distortion. Unfortunately, high switching frequency also means that the chances of radiated noise(like from the HU)is much higher.Well to put it simply,a class d amp will not match an a/b for sonic clarity(at least not yet).I'm sure there are those who will desagree but I have yet to see a class d that will outpreform a a/b in the full range aspect

mabye this will help explain............http://hyperphysics.phy-astr.gsu.edu/hbase...con.html#soucon ..............briang

Bass boost is not a problem,using it incorrectly is.It is a plus for spl.In the video the amp's gain is ajusted for max undistorted output.So when the boost is increased instead of the (nice)sine-wave shown you will of course get a clipped signal,but will it damage your subs?Depends on the subs rms.For instance if you were to run 500watts clipped(bass boost or not)into a sub rated at say 800watts rms then no,it will not.What is happening in this video is that the amp is being pushed into around a 18db overlap(clipped signal).In reality,most ppl set the gain close to a 5db-10db overlap anyway.Also I would like to point out that the sub is not in a box nor is a musical signal being used.Simply put,if your subs rms exceeds(to a degree) the amps output it will not damage the sub no matter if you turn the boost all the way up or not,however you may suffer a loss of sq

I would like to add to make sure the stock hot wire from alternator goes to a fusible link,if it does not DO NOT hook the stock wire back to the alt.The reason is that if the fuse blows on the upgraded wire all power will divert to the stock wire which will result in a fire hazard(I've seen a few cars burn because of this).This is a overlooked mistake because most ppl assume that all cars have a fusible link,however this is not true even on some newer vehicles they do not.Of course this is relevant to the use of high output alternators

current demand up to up to up to up to up to up to up to (amperes) 4' 7' 10' 15' 20' 25' 30' 25-50 12 10 10 8 6 6 4 50-75 8 8 8 6 6 4 4 75-100 8 8 6 4 4 2 2 100-150 4 4 4 2 1 1 1/0 150-200 2 2 2 1 1/0 1/0 2/0 150-200 2 2 2 1 1/0 1/0 2/0 200-300 1/0 1/0 1/0 1/0 2/0 2/0 3/0 300-400 3/0 3/0 3/0 3/0 4/0 4/0 4/0 this chart shows minimum copper wire size acceptable for normal wire lenghts used in a vehicle to meet normal current demands.if aluminum or tinned wire is used,the wire gauge should be even larger to compensate.the wire size calculations are intended to allow no less than .5 voltage drop,assuming that the wire is properly termanated. ------------------------------------------------------------------------------------------------------------------------------------------------- Wire Gauge Recommended Maximum Fuse Size 00 awg 400 amps 0 awg 325 amps 1 awg 250 amps 2 awg 200 amps 4 awg 125 amps 6 awg 80 amps 8 awg 50 amps 10 awg 30 amps 12 awg 20 amps 14 awg 15 amps 16 awg 7.5 amps These are the recommended maximum fuse ratings for the corresponding wire size. Using a smaller fuse than what's recommended here will be perfectly safe. -------------------------------------------------------------------------------------------------------------------------------------------------- proper battery size total rms watts of system minimum battery current 0-50 675 50-100 700 100-150 725 150-200 750 200-250 775 250-300 800 300-350 825 350-400 850 400-450 875 450-500 900 500-600 950 600-700 1000 700-800 1050 800-900 1100 900-1000 1150 1000-1100 1200 1100-1200 1250 1200-1300 1300 1300-1400 1350 1400-1500 1400 1500-2000 1450 2000-2500 1500 2500-3000 1550 3000-3500 1600 3500-4000 1650 4000-4500 1700 4500-5000 1750 5000-6000 1800 6000-7000 1850 7000-8000 1900 8000-9000 1950 9000-10000 2000 ------------------------------------------------------------------------------------------------------------------------------------------------ proper alternator size total rms watts of system charging system upgrade 0-100 10 100-200 20 200-300 30 300-400 40 400-500 50 500-600 60 600-700 70 700-800 80 800-900 90 900-1000 100 1000-1500 110 1500-2000 120 2000-2500 130 2500-3000 140 3000-3500 150 3500-4000 160 4000-4500 170 4500-5000 180 5000-5500 190 5500-6000 200 6000-6500 210 6500-7000 220 7000-7500 230 7500-8000 240 8000-8500 250 8500-9000 260 9000-9500 270 9500-10000 280 ------------------------------------------------------------------------------------------------------------------------------------------------- when using the battery chart remember if 2 batteries are connected in parallel,the current will combine(both batteries current added together)and the voltage remains the same.while in series,the voltage will double and the current will remain the same. ------------------------------------------------------------------------------------------------------------------------------------------------- Here is a simple way to determine average current draw on the electrical system (total rms continous watts * .50 / amplifier effeciency / cars voltage = average current draw on cars electrical system).this is intended for musical signals not tone generators. the reason for multipling by .50 is that .50 represents a musical signal driven to the point of distortion.for bass reproduction you may use (.60).if there is more than one amplifier used,simply combine the results of all amplifiers. ----bG

To calculate the power response of a ported enclosure system, you will need to know the following: Vas = equivalent compliance of driver (litres) Qes = electrical Q of driver at resonance Fs = resonance frequency of driver (Hz) PEmax = maximum input power for driver Fb = resonance frequency of the system F3 = frequency at which response is down by -3dB Dia = effective driver diameter driver (cm) Xmax = peak linear displacement of driver cone (mm) then, Sd = pi*(Dia/100)^2/4 Vd = Sd*Xmax/1000 n0 = 9.64*10^(-10)*Fs^3*Vas/Qes SPL = 112 + 10*LOG(n0) K1 = (4*pi^3*Ro/c)*Fs^4*Vd^2 K2 = 112+10*LOG(K1) Par = 3*F3^4*Vd^2 Per = Par/n0 PeakSPL = SPL+10*LOG(PEmax) where, pi = 3.14159265359 c = speed of sound in air (345 m/s) Ro = density of air (1.18 kg/m^3) n0 = free-air efficiency of driver SPL = SPL of driver @1W/1M Par = maximum linear power output Per = electrical input required to produce Par PeakSPL = Thermally-limited SPL in passband Maximum output at a given frequency F can be calculated as follows: Fn2 = (F/Fs)^2 Fn4 = Fn2^2 A = (Fb/Fs)^2 B = A/Qts+Fb/(Ql*Fs) C = 1+A+(Vas/Vb)+Fb/(Fs*Qts*Ql) D = 1/Qts+Fb/(Fs*Ql) E = (97/49)*A dBmag = 10*LOG(Fn4^2/((Fn4-C*Fn2+A)^2+Fn2*(D*Fn2-^2)) Pmax = (K1/n0)*((Fn4-C*Fn2+A)^2+Fn2*(D*Fn2-^2) /(Fn4-E*Fn2+A^2) SPLmax = K2+10*LOG(Fn4^2/(Fn4-E*Fn2+A^2)) SPLtherm = PeakSPL+dBmag where, SPLmax = displacement-limited SPL at frequency F (dB/1M) SPLtherm = thermally-limited SPL at frequency F (dB/1M) -------------------------------------------------------- To calculate the frequency response of a ported enclosure system, you will need to know the following: Vb = net box volume (litres) Fs = driver resonance frequency (Hz) Qts = driver Q at system resonance Fb = box tuning frequency (Hz) Ql = box losses (Ql=7 can be assumed for most cases) then, Fn2 = (F/Fs)^2 Fn4 = Fn2^2 A = (Fb/Fs)^2 B = A/Qts+Fb/(Fs*Ql) C = 1+A+(Vas/Vb)+Fb/(Fs*Qts*Ql) D = 1/Qts+Fb/(Fs*Ql) dBmag = 10*LOG(Fn4^2/((Fn4-C*Fn2+A)^2+Fn2*(D*Fn2-^2)) ------------------------------------------------------------------------------------------------------------------ To calculate the power response of a 4th order bandpass system, you will need to know the following: Vas = equivalent compliance of driver (litres) Qes = electrical Q of driver at resonance Fs = resonance frequency of driver (Hz) PEmax = maximum input power for driver Fb = resonance frequency of the system F3 = frequency at which response is down by -3dB Dia = effective driver diameter driver (cm) Xmax = peak linear displacement of driver cone (mm) Vr = net volume of sealed section (litres) Vf = net volume of vented section (litres) then, Qts' = Qts*((Vas+Vr)/Vr)^0.5 Fs' = Fs*Qts'/Qts Qes' = Qes*Qts'/Qts Vas' = Vas*Vr/(Vas+Vr) Vb' = Vf Sd = pi*(Dia/100)^2/4 Vd = Sd*Xmax/1000 n0 = 9.64*10^(-10)*Fs'^3*Vas'/Qes' SPL = 112 + 10*LOG(n0) Par = 3*F3^4*Vd^2 Per = Par/n0 PeakSPL = SPL+10*LOG(PEmax) K1 = (4*pi^3*Ro/c)*Fs'^4*Vd^2 where, pi = 3.14159265359 c = speed of sound in air (345 m/s) Ro = density of air (1.18 kg/m^3) n0 = free-air efficiency of driver SPL = SPL of driver @1W/1M Par = maximum linear power output Per = electrical input required to produce Par PeakSPL = Thermally-limited SPL in passband Maximum output at a given frequency F can be calculated as follows: Fn2 = (F/Fs')^2 Fn4 = Fn2^2 A = (Fb/Fs')^2 B = A/Qts'+Fb/(Ql*Fs') C = 1+A+(Vas'/Vb')+Fb/(Fs'*Qts'*Ql) D = 1/Qts'+Fb/(Fs'*Ql) E = (97/49)*A dBmag = 10*LOG((A*Fn2)^2/((Fn4-C*Fn2+A)^2+Fn2*(D*Fn2-^2))) Pmax = (K1/n0)*((Fn4-C*Fn2+A)^2+Fn2*(D*Fn2-^2)/(Fn4-E*Fn2+A^2) SPLmax = SPL+dBmag+10*LOG(Pmax) SPLtherm = PeakSPL+dBmag where, SPLmax = displacement-limited SPL at F (dB/1M) SPLtherm = thermally-limited SPL at F (dB/1M ---------------------------------------------------------- To calculate the frequency response of a 4th order bandpass system, you will need to know the following: Vf = net front volume (litres) Ff = front volume tuning frequency Vr = net rear volume (litres) Fs = driver resonance frequency (Hz) Qts = driver Q at system resonance Ql = box losses (Ql=infinite (10000) can be assumed for most cases) then at frequency F, A = (1/Ff)^2*F^4 B = ((1/Ql+(Fs/Ff)/Qts)/Ff)*F^3 C = (((1+Vas/Vr+Vas/Vf)*Fs/Ff+(1/Qts)/Ql)*Fs/Ff+1)*F^2 D = ((1/Qts+(Fs/Ff)/Ql*(Vas/Vr+1))*Fs)*F E = (Vas/Vr+1)*Fs^2 G = A-C+E H = -B+D dBmag = 20*log(F^2/(G^2+H^2)^.5) ------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------ Port Length The port length required to tune a volume of air to a specific frequency can be calculated by using the following equation: Lv = (23562.5*Dv^2*Np/(Fb^2*Vb))-(k*Dv) where, Dv = port diameter (cm) Fb = tuning frequency (Hz) Vb = net volume (litres) Lv = length of each port (cm) Np = number of ports k = end correction (normally 0.732) The value for k, the end correction, can be fine-tuned by using the following values to derive the appropriate end correction figure for each end of the port, then adding them together Flanged End: 0.425 Free End: 0.307 e.g. if both ends were flanged, k = 0.425 + 0.425 = 0.850 if one flanged, one free, k = 0.425 + 0.307 = 0.732 if both ends were free, k = 0.307 + 0.307 = 0.614 Normally, k=0.732 is assumed In practice, it's best to use ports that are slightly longer than predicted by the above equations, then adjust their length until the correct tuning is achieved. It is much easier to shorten a port than to lengthen it! Minimum Port Diameter To calculate the minimum diameter of the port required to prevent port noises, you will also need to know the following: Xmax = maximum linear displacement (mm) Dia = Effective diameter of driver (cm) Np = number of ports Calculate the minimum port diameter from the following equations: Sd = pi*(Dia/100)^2/4 Vd = Sd*Xmax/1000 Dmin = 100*(20.3*(Vd^2/Fb)^0.25)/Np^.5 where, Dmin = minimum port diameter (cm) Note: You CAN use ports that have a smaller diameter than that given by the equation above, especially if the ports are flared at both ends. However, at higher volumes, you may notice some port noise caused by the air rushing through the ports. Slot Ports If you wish to use a slot port, first determine the diameter of a round port that has the same cross-sectional area as the slot. The following equation can be used to do this: Dv' = 2*((W*H)/pi)^0.5 where, Dv' = diameter of equivalent round port W = width of slot H = height of slot Once you've calculated Dv', you can use it in the equation for Lv above to determine the required length of the slot port to tune the enclosure to the required frequency (Fb) ------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------ To calculate the power response of a sealed enclosure system, you will need to know the following: Vas = equivalent air compliance (litres) Qes = electrical Q of driver at resonance Fs = resonance frequency of driver (Hz) PEmax = maximum input power for driver (W) Fb = resonance frequency of the system (Hz) Qtc = final Q of the system at resonance Dia = effective diameter (cone + 1/3 surround) (cm) Xmax = peak linear displacement of cone (mm) then, Sd = pi*(Dia/100)^2/4 Vd = Sd*Xmax/1000 n0 = 9.64*10^(-10)*Fs^3*Vas/Qes SPL = 112 + 10*LOG(n0) K1 = (4*pi^3*Ro/c)*Fb^4*Vd^2 K2 = 112+10*LOG(K1) Amax = Qtc^2/(Qtc^2-0.25)^0.5 for Qtc >(1/2)^0.5, 1 otherwise Par = K1/Amax^2 Per = Par/n0 PeakSPL = SPL+10*LOG(PEmax) where, pi = 3.14159265359 c = speed of sound in air (345 m/s) Ro = density of air (1.18 kg/m^3) n0 = free-air efficiency SPL = driver output @1W/1M Par = maximum linear power output Per = electrical input required to produce Par PeakSPL = Thermally-limited SPL in passband At frequency F, Fr = (F/Fb)^2 dBmag = 10*LOG(Fr^2/((Fr-1)^2+Fr/Qtc^2)) SPLd = K2+40*log(F/Fb) Pmax = K1*((Fr-1)^2+Fr/Qtc^2)/n0 SPLt = dBmag+peakSPL where SPLd = displacement-limited SPL at F (dB) Pmax = power required to produce SPLd at F (W) SPLt = thermally-limited SPL at F (dB) -------------------------------------------------------- To calculate the frequency response of a sealed enclosure system, you will need to know the following: Fb = resonance frequency of the system Qtc = Final Q of the system at resonance then, Fr = (F/Fb)^2 dBmag = 10*LOG(Fr^2/((Fr-1)^2+Fr/Qtc^2)) where, F = frequency (Hz) dBmag = SPL 1W/1M at frequency F ------------------------------------------------------------------------------------------------------------------- Just for you guys who dont trust the programs(like winISD,ect...)and want to do the math ........ briang

Wow,right outside denham in walker.Moved out of the city (BR)around 5yrs ago to get away from the animals and have some peace....it is'nt country here anymore,there building a mall up the road along with multiple other things.Not a friendly place here anymore.Thinking about eastern Tennessee,been there before and seems to be very nice.Just hate starting over...Also thank you also Aaron for you're concern,man I was sick of new orleans and baton rouge.I am convinced that this state is sinking in more $hit everyday.Well I thank God that my family is safe,once again thanks guys

Another f..king hurricane.Sent the kids off a few days back(good ol granny's).Me and my wife are staying because of all the damn thieves here in south Louisiana.We were planning on selling and moving in a few years,but with the crime and everything else it may be alot sooner

Too light,I can barely read anything.Ohh and happy birthday to me,well it was the 20th.Hope the site stays up this time

I have some good ol'pic's. punch 18",rf15",and some more bare with me.I dont have it set-up to post them yet,I think i may have some black widow's too!shit from the 80's

yea,the advice i've seen on there borders retardation.I dont care for either site.Are they sponsored by some audio companies I wonder,seems like it.

Had 8,with 2 orions. Did 167 with music,no tone or sine wave generator.sounded shitty though

Is it me,or does the site carstereo seem alot like ROE???

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