WildPlumDx Posted March 14, 2009 Author Share Posted March 14, 2009 that pioneer 600w only does 60 Watts x 4, at 4 ohms <= 1% THD+N where this fusion does 75 Watts RMS per Channel @ 4 ohms http://www.soundaround.co.nz/shop/ampli ... plifier-en and its cheaper than the pioneer but i dont think it will just hook up to my headunit the way the pioneer says it does hmmm any suggestions on amps would be great also would like to run at 4 ohms as i heard its more clean ? Quote Link to comment Share on other sites More sharing options...
84_S12 Posted March 14, 2009 Share Posted March 14, 2009 It's not about the actual impedance rating. In reality the impedance is an average of the readings from all the speakers in the system ie splits (Tweets tend to present less of a load than woofers for example) it's just provided as a nominal figure. An amplifier designer will have designed the amplifier with an expected load so yes it MIGHT sound best with speakers that represent this load, but it's not the final word. 4 ohms is pretty much a standard for car audio components I think anyway, you could run 8 ohm speakers but they would be quieter than 4 ohm speakers... and so the opposite is true with lower impedances. If I were you I would aim for around 80W x 4 as an amp output it doesn't matter if you slightly overdrive your 75 watters for example, but you want to make the most of your 85 watters rather than underdrive them so you're looking for something around 800W that can take speakers level inputs or output 4 channels from a single pair of preouts, otherwise you'd be looking to use those things I showed you from Jaycar. I can't offer much more than that advice wise as far as models and specs for car audio I don't know what's out there so I'll leave that up to you? Peace Ryan Quote Link to comment Share on other sites More sharing options...
forced Posted March 14, 2009 Share Posted March 14, 2009 .I know this shit inside and out. Yeh, right..... tui ad. Running a speaker over its power rating heats the coil up nowhere near as much as putting a constant DC voltage into it, which is exactly what clipping is. The only amp that puts out a constant DC is a broken amp. Clipping at it's extreme is a low frequency DC squarewave at the lowest frequency of the input signal. A home amp system works a bit different from a car system. The input signal on a home amp is constant, and the output volume is controlled on the amp itself. On a car, the volume is controlled from the headunit so the input signal is variable. When the volume is turned up too high / gain set incorrectly the amp tries to recreate the waveform yet doesn't have enough output power to complete it, hence the clipping. A home stereo works on exactly the same principle, there's a preamp stage with volume, tone, balance etc controls, that's fed into the power amp section. In a headunit the power amp runs off 12V and earth, the speakers normally float at a 6V DC with the signal over the top of it, or in the older low power systems, the speakers are earth return with only half the max power (with inbuilt capacitors to block DC to the speakers). A home stereo , like a car power amp will run off dual + and - supplies 30 to 50 volts, depending on power rating. Clipping only happens on a rubbish amp or a rubbish installation. It's caused by 1 of 3 things, too much input signal, too low supply voltage or the amp is too hot. I have 40wrms speakers and have been giving them 104wrms daily for the past 2.5years and they are still as good as the day I got them So, you've either got permanent hearing damage or you're telling porkies.... well done. It has one PAIR of RCA preouts, should you wanna run 4 channels all through the amp you'll need 2 pair as splitters reduce the signal level. It's up to you obviously. The RCA output is a preamp output, that goes into a high impedence input on the amp, splitting it does NOT reduce the signal level. also would like to run at 4 ohms as i heard its more clean ? It's all about signal to noise ratio. A higher impedence speaker will always give a better signal to noise ratio. A lower impedence speaker will give more power output for the same supply voltage. Using a headunit's power amp through an adapter (to reduce the level) to an external power amp will always give a worse signal to noise ratio than using the headunit's RCA output and feeding that to an external power amp. It's not about the actual impedance rating. In reality the impedance is an average of the readings from all the speakers in the system ie splits (Tweets tend to present less of a load than woofers for example) it's just provided as a nominal figure. Ryan Impedence is dependant on frequency, a tweeter has a very high impedence at low frequency, a bass speaker has very high impedence at high frequency. The crossover network is really a frequency dependant filter. Z squared =R squared + X squared where Z = impedence R = resistance X = reactance. X = 2 pi FL Or something like that. Shit I've already forgotton more that most of you have ever learned. Where F = frequency and L = inductance Steve Quote Link to comment Share on other sites More sharing options...
forced Posted March 17, 2009 Share Posted March 17, 2009 I've been thinking again, yes dangerous. Suppose you've got an external power amp that uses + - 30V supplies. Then the maximum power that it can output into a 4 ohm speaker is 30 x 30/4 watts, just very roughly, so that's 225W per channel. That can only happen when you've cranked up the input to the max so that it's outputting squarewaves. That particular amp , if setup correctly would output a sinewave with a peak of + - 30V maximum. The RMS voltage would be .707x 30 so that would be round about 21v RMS and the RMS power output would be 21 x 21 /4 or close to 110W. Hmmmm maybe I've made a mistake but it's pretty obvious that as you pump too much input into it, the power output rises dramatically. So, when the amp is clipping, the speakers crap out..... of course they do, they can't handle the power. So, if you've got a 110W amp you need speakers with greater power handling capacity. It makes me wonder how these "pro" installers actually set them up.Guesswork? A proper qualified tech would use a scope if it were his own setup, a test disc or tape with a tone at the right level and one scope input to the signal input, the other scope input to the speaker output, then lay one trace over the other to check for distortion. Getting OT but it pays to never listen to salesmen. Steve Quote Link to comment Share on other sites More sharing options...
Ned Posted March 17, 2009 Share Posted March 17, 2009 Another way to quickly see how much power the thing can put out is by looking at what fuse was fitted standard. Heres some math. 14.4V supply (you dont have 14.4 at the battery but lets use these super max figures) and 2 10A fuses (one for 2 channels of a 4 channel amp) and lets assume that the people who made the amp are amazing and got 80% efficiency out of the amp yes? (means that the amp puts out 80% of the power it uses into the outputs and 20% is transferred into heat really... thats why the thing gets hot, if it was 100% efficient it wouldnt need a heat sink etc and would stay cold all the time) Now 14.4V * 10A * 80% / 2 channels < 60Watts per channel. So as a rule of thumb, the amp can put out roughly 10 times the power then the fuse is rated in watts. 10A fuse, 100W output at 12 and a bit V and around 80% efficiency. Cheap amps are more like 30-60% efficient and claim to be able to do 1600W and have a 10A fuse for all 4 channels see how thats funny? lets do the math. 14.4V (optimistic again) * 10A * 50% efficient (optimistic again) = 72Watts of actual power that it can put out. Those arent the MAX ratings, they are kinda like the RMS (but NOT the actual RMS) IMPORTANT FUCKING NOTICE!!!! Do NOT put a bigger fuse in your amp to get more power out, thats NOT how it work and if you dont know why not, then do not play with ANY electronics please... none..... Please use this as a guide line rule of thumb thing to simply laugh at stupid claims of power etc Quote Link to comment Share on other sites More sharing options...
fuel Posted March 17, 2009 Share Posted March 17, 2009 guys take it easy on the shit-slinging eh.. surely there's a more mature way to discuss this topic. from having a quick read I think both parties have perfectly valid points, Steve you probably do go about wording the posts a little arrogantly but you other guys are just ragging on him for the sake of ragging on him. Quote Link to comment Share on other sites More sharing options...
fuel Posted March 17, 2009 Share Posted March 17, 2009 also, I feel this is probably a bit more tech for the general section now (wildplum you have a habit of posting tech questions in general ) - anyone have any problems if I move it to tech/ice section? Quote Link to comment Share on other sites More sharing options...
Yowzer Posted March 17, 2009 Share Posted March 17, 2009 So, when the amp is clipping, the speakers crap out..... of course they do, they can't handle the power. It's not that they can't handle the power, it's that they can't handle a dc voltage. Plug an old speaker straight up to a 12V battery and see how long it lasts. Now picture how long it lasts at 30V. It will, in most cases, be the installers fault as a correctly set up gain, input voltage and crossover will prevent the problem. But wtf is the point in running a 100W speaker on a 50W amp? Wasted potential right there. The damage occurs when carnies try to get 100W from their 50W amp by cranking the gain to beyond what the amp can provide. .I know this shit inside and out. Yeh, right..... tui ad. Steve Ouch, Yowzer, I think you just got burned Shit yeah, I guess I just fluked a $8k+ install On a side note, we are actually a mile off topic here. BRB while I read the original question... Quote Link to comment Share on other sites More sharing options...
Yowzer Posted March 17, 2009 Share Posted March 17, 2009 ok i toally have no idea about car audio but i have a head unit pioneer one with one rca only and i have 2 sets a fusion 6.5 components one in front one in rear, just wondering if i would benefit from an amp much with the set up and was looking at those cheap v12 amps on trade me as i'd need a 4ch amp correct ? will i be able to run this off a headunit with one rca ? would it even be worth amping my speakers? Allrighty... Summarize time. You said your speakers were 85W and 70W rms? You will definitely benefit from an amp as head units only put out 50W max. An amp will usually allow for better quality as well, plus the advantage of cranking some lower frequencies. Aim for an amp around the 80W-100W rms mark. Some amps have the high voltage input where you can connect them directly to the headunit speaker output, others do not so you could use the things that 84_S12 was talking about. You can also run 2 RCA splitters to run them directly from the pre outs, however you will not be able to adjust the front-rear balance from the head unit. Not that that's really a big deal as ya can set it on the amp anyway. I know I've just repeated alot that others have said, but there it is, all summarized into one answer. Quote Link to comment Share on other sites More sharing options...
Spencer Posted March 17, 2009 Share Posted March 17, 2009 So, when the amp is clipping, the speakers crap out..... of course they do, they can't handle the power. It's not that they can't handle the power, it's that they can't handle a dc voltage. Plug an old speaker straight up to a 12V battery and see how long it lasts. Now picture how long it lasts at 30V. Dude your missing steves point. Its not the dc power at all although placing a dc voltage over an inductor will cause the current to rise to a very large value this is not whats happening with clipping. Think of a clipped basic sinusoidal wave form (it has 'flat' tops) it has more area under it than a smaller maximum unclipped waveform. Therefore the amplifier is putting out more power which can damage the speakers Should move it phill Quote Link to comment Share on other sites More sharing options...
forced Posted March 17, 2009 Share Posted March 17, 2009 Shit yeah, I guess I just fluked a $8k+ install ... So how did you set up the gain so you know that it's not distorting? Genuine question, I'm sure others would also like to know. Steve Quote Link to comment Share on other sites More sharing options...
Ned Posted March 17, 2009 Share Posted March 17, 2009 this should so be locked More shit to read guys Click me Quote Link to comment Share on other sites More sharing options...
WildPlumDx Posted March 17, 2009 Author Share Posted March 17, 2009 yeah i thought it was a general question then it exploded into this lol... feel free to move the post if you must, at the end of the day all i want is my 4 fusion components with 2 at 70rms and 2 at 85rms to be powered by this http://www.trademe.co.nz/Trade-Me-Motor ... 392766.htm or http://www.trademe.co.nz/Trade-Me-Motor ... 611014.htm Quote Link to comment Share on other sites More sharing options...
fuel Posted March 17, 2009 Share Posted March 17, 2009 I think either amp will be fine - you're not going all out on a big budget sound install so either amp will suffice. I have the sony amp and would rate it good for the price. I just used a pair of RCA splitter 'Y' cables to multiply two channels into four for front and rear. just make sure you mount the amp somewhere where it has ventilation (but hidden from prying eyes and kicking feet) as amps can get a bit hot. definitely have a decent power feed and make sure it's fused as close to the battery as possible! Quote Link to comment Share on other sites More sharing options...
WildPlumDx Posted March 17, 2009 Author Share Posted March 17, 2009 yeah i dont want hardout sounds just want my speakers to go better and cleaner, the sony is cheaper might go for that! Quote Link to comment Share on other sites More sharing options...
Yowzer Posted March 17, 2009 Share Posted March 17, 2009 Shit yeah, I guess I just fluked a $8k+ install ... So how did you set up the gain so you know that it's not distorting? Genuine question, I'm sure others would also like to know. Steve Ears. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted March 17, 2009 Share Posted March 17, 2009 So, when the amp is clipping, the speakers crap out..... of course they do, they can't handle the power. It's not that they can't handle the power, it's that they can't handle a dc voltage. Plug an old speaker straight up to a 12V battery and see how long it lasts. Now picture how long it lasts at 30V. Dude your missing steves point. Its not the dc power at all although placing a dc voltage over an inductor will cause the current to rise to a very large value this is not whats happening with clipping. Think of a clipped basic sinusoidal wave form (it has 'flat' tops) it has more area under it than a smaller maximum unclipped waveform. Therefore the amplifier is putting out more power which can damage the speakers Should move it phill Nah I know that boe, but I'm saying that even if a speaker can normally handle the power, clipping can still damage it. Ya could have a speaker that can happily take 200W all day long, but if the amp is clipping out at 150W while trying to reproduce a 200W output it can still stuff up the voice coils. Mate of mine killed a sub that way. Rated at 700W/1500 max but the amp could only put out half that. Him being a tool cranked the gain up too far and burned out the vc. I was running the same sub at 1000rms (2 ohms) and it was mint Quote Link to comment Share on other sites More sharing options...
WildPlumDx Posted March 17, 2009 Author Share Posted March 17, 2009 what u guys think of this amp ? http://www.trademe.co.nz/Trade-Me-Motor ... 447569.htm Quote Link to comment Share on other sites More sharing options...
fuel Posted March 17, 2009 Share Posted March 17, 2009 haven't had anything to do with lanzar so can't comment - probably no different than fusion, sony xplod etc (ie they're all middle of the range) Quote Link to comment Share on other sites More sharing options...
Raizer Posted March 17, 2009 Share Posted March 17, 2009 You get what you pay for aye. I have no experience with Lanzar amps but if there the same quality as there subs and head units they will be shit. http://www.trademe.co.nz/Trade-Me-Motor ... 557019.htm http://www.trademe.co.nz/Trade-Me-Motor ... 562753.htm (should be 4x100rms, my old 2.880's were 2x440rms) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.