Hey there audio gurus,

So i've got a problem with my amp, was driving to work 2 nights ago and suddenly the subs stopped going boom.
I have tested RCA, all fuses i can think of, power and earth leads and the speakers themselves. Doesn't look like there is any power going into the amp.

model is the same as this one:
http://cgi.ebay.com.au/Pionner-800watt-monoblock_W0QQitemZ250481474536QQcmdZViewItemQQptZ AU_Car_Parts_Accessories?hash=item3a51dbfbe8&_trksid=p3286.c0.m14

Any suggestions on what may have died/blown in the amp? Are these poor quality amps or do they have common problems?
When I first bought the amp I found i had to crank the gain right up and the bass boost on +12db to get any sound out of it (still sounded ok though), could it just be worn? I did buy it 2nd hand.

any help would be great!
cheers!

You probably had to crank it right up because its only 360w RMS running in the config you had it, which is half the power your subs probably wanted (trying to remember your model sub). As for reasoning it might have blown, if all the fuses are ok, it's probably because you had it going full bore all the time with maximum bass boost, which eventually would've killed it.

I'd check all the earths and stuff though just in case. Even the remote wire is worth checking!

You probably had to crank it right up because its only 360w RMS running in the config you had it, which is half the power your subs probably wanted (trying to remember your model sub). As for reasoning it might have blown, if all the fuses are ok, it's probably because you had it going full bore all the time with maximum bass boost, which eventually would've killed it.

I'd check all the earths and stuff though just in case. Even the remote wire is worth checking!

Yeah checked the remote wire as well.

I didn't have it cranked loud when it blew, and i don't think i had the amp that loud during normal operation, sure cranked it every now and then but it wasn't THAT loud (no louder than the boss audio amp).

My subs are 350wrms each, MTX thunder 6000's. I actually think my boss audio amp may have put out more power.

Sometimes, just sometimes - audio gear goes to audio gear heaven.

As for why it died? could just be old age.

I'd put another amp in its place, that you know works - this would eliminate the possibility of it being a wiring/headunit issue. If another amp works, then not much more you can do.

P.S No I would never buy a pioneer/boss amp - it is cheap gear, same with kenwood - not saying you need a $1000 monoblock - just something thats put together a bit better.

If you're going to buy a new monoblock I'd recommend Rockford Fosgate/Alpine etc. Unfortunately pioneer/kenwood/sony don't have a very good reputation for speakers and/or amps. They're poorly constructed unforuntately. Personally I'd recommend the Rockford Fosgate P300-1, it can be had for $400, and you know you're buying quality when you buy rockford stuff. Especially since its the Punch series. The Prime series are also pretty good too.

I'm after something that will drive the subs well, but not too pricey. So something with 6-700wrms output, and around the $3-400 mark. Am I dreaming?

GEEZ - 600-700 RMS?? Thats a huge amount of RMS power! For a decent brand you'd be definitely looking at over $600. Do you mean Peak power? Clarion might be a good option. They're very decent for the price and probably much better than the Boss/Pioneer you had. You might be able to get a 750W for around $550. I would still recommend Rockford Fosgate or Alpine thou.

I'm after something that will drive the subs well, but not too pricey. So something with 6-700wrms output, and around the $3-400 mark. Am I dreaming?
Jaycar Response Mono. That's the most powerful reliable amp you'll get without spending too much.

http://www.jaycar.com.au/productView.asp?ID=AA0460&keywords=response&form=KEYWORD

Jaycar Response Mono. That's the most powerful reliable amp you'll get without spending too much.

http://www.jaycar.com.au/productView.asp?ID=AA0460&keywords=response&form=KEYWORD

reading through, was gonna say the same thing!!

We should probably check the subs as well, most MTX are SVC 4ohm, are your subs the same?

Yeah I would also be checking the subs... May be possibly the Voice Coils could have caused the amp to go pop

well hook the amp up to somthign else and have it REALLY low - check for power at all power cable etc...

I may be mocked for this lol but i have been running a "BESERK" amp for about 4 years now... in its early days i CRANKED THE HELL OUT OF IT its 600wRMS and i bought it USED for $50 off ebay.

I never had a prb with it till now... they come in 600wrms or 1000wrms...

The sub i run is 750wrms - and it handles it fine.

Look into it may be able to pick one up pretty cheap - a mate of mine got one for about $120 brand new... retail was like $300 or somthing like that

I haven't tried powering something else with the amp or the subs on another amp yet, will make sure of that.
Yeah the subs are svc 4 ohm.
Only reason why i'm saying 6-700 wrms is I don't want to underpower my subs if that is what caused this amp to go, I had a 1200w max boss audio 4 channel which still works and was much louder than the pioneer amp.

Underpowering the subs wont destroy the amp.

How the amp is used is another matter, that said going by your posts I doubt you consistantly pushed the map into clipping. If you did, you would have caused the subs to go first.

Amps are generally pretty tough, can take a wallop - and the speakers/subs are the weakest link.

That being said - if the subs are severly underpowered (say the amp puts out 300wrms, and your subs need that each), you're more than likely running the amp at 90%+ consistently, meaning the amp will fail sooner rather than later. Its like redlining your car in every gear, every day - sooner or later something will break - its not just 'abuse' its the fact you're expecting 90-100% every time, things wear out quicker.

So in short - yes, having more than enough power is a good thing.

Yea - underpowering subs to a degree wont damage them - as long as they pump - if the power isnt sufficent to make them pump at all - then you can cause damage to them (heat the voice coils etc)

Best to get a powerful amp, and ALWAYS have hte amp tunred down, bass boost medium, gain medium etc... coz if you put it all up, and you crank it at the CD player, then your amp wil be pushed really hard, but if you have the amp tuned down, even when you crank your music up - the amp wont be kiling itself.

Yea - underpowering subs to a degree wont damage them - as long as they pump - if the power isnt sufficent to make them pump at all - then you can cause damage to them (heat the voice coils etc)

Best to get a powerful amp, and ALWAYS have hte amp tunred down, bass boost medium, gain medium etc... coz if you put it all up, and you crank it at the CD player, then your amp wil be pushed really hard, but if you have the amp tuned down, even when you crank your music up - the amp wont be kiling itself.

Bass boost off......

Bass boost will only boost a certain frequency (usually around the 40-45Hz region). Granted factories do this at a 1st or 2nd order bandpass (umm......where the frequency eitherside of this boosted frequency drops off at either 6dB or 12dB per octave.)

So in turn for every dB you up on bass boost, you're forcing your amp to work a lot harder than simply turning up the gains.

Basically, if you're unsure of just how much you can push an amp, dont use bass boost - it has the ability to turn your subs into paper weights. Bass boost can send your amp to clip very fast, clipping is what will kill speakers.

Definitely didn't hear any clipping on the subs, i've heard clipping before and it wasn't that.

Guess the amp may have just worn out, will take it a part over the weekend and see if there is anything obviously blown.

You usually see the results of clipping before you hear it - i.e. smoke.

Unpowering your subs is like forgetting to get your partner a Birthday present. If you have 700wrms of subs I would try around 1000wrms of amp power. Not only will everything run smoothly - but if you see a graph of how power is delivered vs THD - the more power the better.

If you add 6db of bass boost, it is adding 4x the boost to a selected Hz, that is like having your gain on 1/4 and adding the boost would have it on 3/4 - max - again very bad. You can only imagine 12db :think:

I've found turning the gains right down, turning the headunit up to 3/4 - 4/5's then adjusting the gains up slowly provides the best results, with all that enhancement crap off (like your bass boost on a mono).

ihave bass boost switched off - gain is up a lil (medium) and freq on 60hz - i find this is the besttttt result - you'll need a powerful sub to have the freq on 60hz and get a good amoun tof bass, shakes the car, massages your back, but doesnt feel like its pounding in your ears as it does with 100hz +

ihave bass boost switched off - gain is up a lil (medium) and freq on 60hz - i find this is the besttttt result - you'll need a powerful sub to have the freq on 60hz and get a good amoun tof bass, shakes the car, massages your back, but doesnt feel like its pounding in your ears as it does with 100hz +
What? You realise that gain levels and the LPF (presumably thats what your talking about with 60hz) will vary with every sub and amp combination? 60hz LPF would be horrible for most of my music, you'd be leaving a gap between the speakers and sub. It's impossible to tell people what they should have their amp settings on, you need to tune it to the individual components in the car.

sorry but just reading through this thread and saw 'clipping' and ive wired up my system myself and not 100% on stuff so was just wondering what you guess mean by clipping?

cheers

ihave bass boost switched off - gain is up a lil (medium) and freq on 60hz - i find this is the besttttt result - you'll need a powerful sub to have the freq on 60hz and get a good amoun tof bass, shakes the car, massages your back, but doesnt feel like its pounding in your ears as it does with 100hz +

The other issue is bass becomes directional around 100Hz.

Bass from around 70Hz starts to play some of the lower vocals, guitars and various other bits.

63Hz is optimal in most cars. If you could find a good set of fronts to play down to 50Hz with a decent bit of volume (8" for instance) then you would put the sub x-over at 50Hz

sorry but just reading through this thread and saw 'clipping' and ive wired up my system myself and not 100% on stuff so was just wondering what you guess mean by clipping?

cheers

Taken from FHRX Studios - www.fhrxstudios.com.au


How can I destroy my speakers?

When asked how one can destroy speakers we reply by explaining there is only three real ways. The first is thermally and this is the most commonly occurring. Breaking the equation down further there are only two ways to thermally destroy a speaker (and crossover in the case of split systems); over powering and under powering. Over powering the speaker with way too much power will cause the voice coil wire (which is receiving more current through it then its rated too) to melt and short on the magnet. This is simple enough to understand so if you have a 200 watt subwoofer then you don't feed it 2000 watts. However much more dangerous is under powering the speaker because the end result will be the same but it happens in a slightly slower and sneakier way.

In audio systems where you hear speakers 'distorting', it's not the speaker that is causing the struggle, it's the amplifier. Speakers are quite simple devices and don't discriminate. They cannot tell the difference between harmonic sound and rough distorted noise and simply reproduce whatever wave signal is given to them regardless of what it may sound like. When you ask the amplifier to do its job (by turning the volume up) it takes a comparatively small sound wave and amplifies it before sending this bigger signal to the speakers. If you ask your amplifier to produce more than it's capable of it will attempt to achieve this request but the output sound wave becomes rough and distorted as the amplifier reaches its power output threshold. Pushing it beyond this point causes the amplifier to begin clipping. When a woofer is driven hard by a high power amplifier there is a significant amount of current flowing through the voice coil. The voice coil has resistance and therefore a voltage drop across it occurs. This means that there may be a great amount of power being dissipated in the form of heat within the voice coil. When a speaker is driven with clean power the cone moves back and forth a great deal. You'll notice many speakers have perimeter vents in the basket and pole vents in the back. The speakers movement forces air to flow in through these perimeter vents and into the magnetic gap (the area where the voice coil lives and moves) before flowing out the pole vent (and hopefully taking the heat with it). When the cone moves forward out of the basket, the area that's under the dust cap and around the voice coil increases in volume. This pulls cool air into the magnetic gap. When the woofer moves the other direction, the chamber size is reduced and the hot air is forced out of the pole vent. This air flow cools the voice coil.

http://www.fastfoursforumscarclub.com/temp/fhrxstudios/images/amp_clipping.jpg

When a relatively low powered amplifier is driven into clipping (to the point of full square wave sometimes) the voltage delivered to the voice coil no longer resembles a sine wave because the amplifier clips the top and bottom of the wave off (because it's beyond what it can do). While this output is clipped (the flat spot on the top of the wave) the voice coil in your speaker is not moving but instead remains almost stationary at this time with high current still running through it. Because the voice coil is not moving it is not being cooled sufficiently (remember the coil is driven by a linear motor therefore the more voltage applied to the voice coil, the further it moves). In the image above you see that at points A, B, D, E, F and H the voltage is changing causing the voice coil to move in the gap and therefore pull in fresh cool air. At points C and G, the voice coil is still moving a little but this is only due to momentum. This is not enough to cool efficiently and there is still full current flowing through the voice coil. Since the displacement of the voice coil (and the relating airflow around it) is no longer proportional to the heat being generated, the voice coil will overheat. This excess heat (just as with overpowering) causes the voice coil to melt its insulation and the former to physically distort. Basically the whole motor burns apart as adhesives start to fail. However before you stress too much it should be noted that many reputable manufacturers underrate speakers so generally slight clipping isn't a problem. Severe clipping is more likely to cause a problem.

The second way to destroy a speaker is physically and this can also be broken down into two facets. The first physical facet is what we call bell mouthing. This is where the voice coil and former are driven so hard they actually extend beyond their normal range of motion and impact the back plate on the bottom of the speaker. This continual impacting causes the bottom of the voice coil to bend out like the bottom of a bell and this eventually cause the coil and corner to become so physically disfigured that it rubs on the magnet surrounding it and eventually comes to a complete halt. This isn't just restricted to subwoofers either. Tweeters playing frequencies that are too low tend to suffer from this phenomenon too because they're not designed for high excursion. The second facet of physically destroying a speaker is to punch way too much power into it fast and this causes what us engineering types like to call critical structure failure. That is a technical way of saying you'll simply tear the surround and/or spider(s) and pop the cone and motor assembly right off the frame. To 'blow the guts out of the speaker' is the more Aussie way of saying it. This is commonly witnessed during sound pressure level competition because the drivers are being pushed to their absolute limits.

The third and final way to destroy a speaker is an age old enemy of technology; sunlight. Nothing breaks down and erodes foam surrounds faster than sunlight (well except bugs like moths but you shouldn't have them living in your car). After only a few months of direct sunlight your speaker surrounds will be significantly weakened and may eventually begin cracking or simply tear all together. Butyl rubber surrounds are more resistant to sunlight but eventually all materials succumb to the mighty sun. The best thing to do with shelf speakers is place some grille cloth over the factory grilles. This helps in resisting ultra-violet rays from the sun penetrating through to the speaker.

These are the three main causes of most damaged speakers. The end result is the same with all three methods but you tend to get a lot more warning with thermal or sunlight damage. Physically speaking though; if you're pushing your speaker way beyond what its rating dictates you'll get very little warning before your speakers starts to smoke or literally explodes.

What is severe clipping?

Now that you know about clipping (see above) we move to severe clipping (a.k.a square wave). It always amazes me when I hear some idiot driving down the road and the audio is clearly distorted (you know what I mean). Many people drive their amplifiers into what could be called a square wave output (white line below). When an amplifier is pushed that hard, it is actually possible to drive the speaker with twice as much power as the amplifier can cleanly produce into the speaker. As you can see below, the yellow sine wave is the maximum 'clean' output that the amp can produce. When an amplifier is pushed way too hard, the signal will eventually look like the white line. The effective voltage of the white line is ~1.414 x the yellow line. This means the total power driven into the speaker by the clipped (square wave) signal is double the power delivered by the 'clean' signal (yellow line). This means that the power is double but the cooling of the voice coil will not increase in proportion with the power increase (since the voice coil isn't moving as much as it needs to be for the given power dissipation). This will lead to the voice coil overheating. If we compared the output of a 100 watt amp (the one that's clipping) to a 200 watt amp, the 200 watt amplifier would be able to push the speaker as much as 40% farther than the 100 watt amp (depending on the frequency of the signal). This extra travel (in each direction from its point of rest) would result in added airflow around the voice coil.

http://www.fastfoursforumscarclub.com/temp/fhrxstudios/images/amp_extreme_clipping.jpg

Note: The RMS voltage of a pure sine wave is equal to the peak voltage multiplied by 0.707. The RMS voltage of a pure square wave it equal to the peak voltage. For 2 waveforms with equal amplitude (as shown above), the RMS voltage of the square wave is 1.414 times the voltage of the sine wave. If we use the example of the 100 watt amp which can produce a sine wave of 20 volts RMS, we can see that the output power at hard clipping is double the power it can produce cleanly.

What is distortion?

Well, to get a little more complicated, distortion is any departure from a true and accurate reproduction of the original waveform. It can include Noise, Clipping Distortion, Harmonic, and Intermodulation Distortion. These last two forms are fairly common in loudspeaker reproduction and can be reduced but not entirely eliminated in the existing technology. It would be fair to say that modern amplifier design fairly eliminates nearly all forms of inherent perceived distortion, leaving only that caused by inappropriate user settings and overloading.

Distortion is the name given to anything that alters a pure input signal in any way other than changing its size. The most common forms of distortion are unwanted components or artifacts added to the original signal, including random and hum-related noise. Distortion measures a system's linearity - or nonlinearity. Anything unwanted added to the input signal changes its shape (skews, flattens, spikes, alters symmetry or asymmetry). A spectral analysis of the output shows these unwanted components. If a circuit is perfect, it does not add distortion of any kind. The spectrum of the output shows only the original signal - nothing else - no added components, no added noise - nothing but the original signal.

It's rather amusing to see amplifier manufacturers making great claims about the advantage of the extra .001 % Distortion they've wrung out of their products, while most speakers are considered very good if they can keep such distortions below 5 %. It's true that the reduction of any distortion anywhere is a positive contribution to the goal of high fidelity, but the disparity between the two technologies in this regard points up the largely subjective nature of many such claimed advantages.

Here are some of the definitions:

* Noise is perceived sounds not in the original soundtrack. Such things as hiss, crackle, pops, hum, and buzz, are typical of the types of extraneous signals described as noise. Inherent noise in the electronic processing in any sytem is measured in decibels relative to the amplitude of the original signal. Sounds perceived as noise are heard in contrast to the sound that is the object of attention. Thus, a noise signal measured at 15 deciBels below the output of Tchaikovski's 1812 Overture finale would probably not even be heard; while a slight hiss at 55 dB below the level of a soft piano passage would be annoyingly obvious.
* Harmonic Distortion is a type of Distortion in which resonance or sympathetic ringing vibrations are added to the original sound to produce second and third harmonics of a fundamental tone in a way that was not present in the original signal. Choosing good Drivers and a well-made enclosure design is essential in overcoming this tendency in speakers.
* Last but not least (well maybe) is Intermodulation Distortion. This is the Distortion that results when one set of frequencies is superimposed on, or is modified by, another to produce a third frequency not present in the original signal. Quantifies the distortion products of nonlinearities in the unit under test that causes complex waves to produce beat frequencies, i.e., sum and difference products not harmonically related to the fundamentals.

Cheers for that Ers, very interesting and i actually understood it :) haha

So what does clipping actually sound like?? Is it just distortion?

So what does clipping actually sound like?? Is it just distortion?

Yes. It can also smell, alot!!

What? You realise that gain levels and the LPF (presumably thats what your talking about with 60hz) will vary with every sub and amp combination? 60hz LPF would be horrible for most of my music, you'd be leaving a gap between the speakers and sub. It's impossible to tell people what they should have their amp settings on, you need to tune it to the individual components in the car.

YES i am aware of that - each amp needs to be individually tuned to the sub and ALSO to the music type you like to listen to. I like mostly RnB... i wasnt recomending what tune have, just stating what i had on mine.

YES i am aware of that - each amp needs to be individually tuned to the sub and ALSO to the music type you like to listen to. I like mostly RnB... i wasnt recomending what tune have, just stating what i had on mine.
Then why recommend doing something different to what you think is best? Your wording also suggested generalization of what you find best, not what you've found best for your system :P Dare I say just a misunderstanding.


Best to get a powerful amp, and ALWAYS have hte amp tunred down, bass boost medium, gain medium etc... coz if you put it all up, and you crank it at the CD player, then your amp wil be pushed really hard, but if you have the amp tuned down, even when you crank your music up - the amp wont be kiling itself.


ihave bass boost switched off - gain is up a lil (medium) and freq on 60hz - i find this is the besttttt result - you'll need a powerful sub to have the freq on 60hz and get a good amoun tof bass, shakes the car, massages your back, but doesnt feel like its pounding in your ears as it does with 100hz +

Now now children.....

I use a 2nd order LPF on the sub at 63Hz (12dB/octave)

Then 3rd order HPF on the fronts at 63Hz (18dB/octave)

This allows for a decent overlap and to bring the sub forward. However as said, each car must be tuned to its components.....p.s eclipse decks rock :P

Love this emot.. :gfight:

Tuning is a personal thing. Would suggest starting at least at 80Hz and working your way down - especailly if you only have a 12db/oct xover.

Love this emot.. :gfight:

Tuning is a personal thing. Would suggest starting at least at 80Hz and working your way down - especailly if you only have a 12db/oct xover.

Yeah whats up with only having those Xovers? :P

Yes tuning is a personal thing, hell I keep retuning on the run.....cant wait till FHRX gets his hands on it, he'll do a better job in 1minute :eeek::facejump:

Then why recommend doing something different to what you think is best? Your wording also suggested generalization of what you find best, not what you've found best for your system :P Dare I say just a misunderstanding.

LoL ok what ever helps you sleep at night...

OK so update, found the problem and only cost me $1 to fix lol.

Did some multimeter tests, only 8v going through the power cable to this amp (very odd i thought).
When putting load on it, dropped down to 2v, WTF? I says.
So traced back the power wire to the battery, battery to the first fuse, OK.
Battery to after the fuse, BINGO.

Tested the fuse, was reading 1000 ohms of resistance. So somehow my fuse, turned itself into a resistor (dads an elec technician and he said he has seen it only once before and it is a very odd thing to happen, but it does rarely). So a $1 power lead fuse later and i'm back in business.

Also discovered my pioneer amp LPF was set to 45hz.....no wonder my subs were quiet LOL. Turned it up to about 80hz and it's running much better and louder. So at least some good has come of this.

Thanks for all the help guys :).

Hey M4DDOG how did you adjust the LPF on your pioneer? I have the 2ch version of your amp but I cant actually adjust the frequency on mine? I just have High/Low/Full.... :(

Rory, read your manual.

If its not adjustable (LPF/HPF generally have a dial you can turn, looks like a gain control), then your manual will tell you what your LPF and HPF crossover will be.

Regardless of wether you use LPF or HPF, make sure you have your subsonic filter ON. Hopefully your amp has this, it kills 15Hz and below at around 18dB/octave (depending on the amp). Some amps have the ability to adjust this filter.

Hey M4DDOG how did you adjust the LPF on your pioneer? I have the 2ch version of your amp but I cant actually adjust the frequency on mine? I just have High/Low/Full.... :(

80Hz fixed xover @ 12db /oct. This is for both LP and HP filters. Full simply turns it off.

Unfortunately that can not be adjusted.

ahh ok, cheers guys.