Speaker upgrade - Alpine

[CatmanV2]

An AC signal on a speaker? That would just be a buzzing noise surely?

Umm, not really, no. I mean it *might* be, but probably only if it's a square wave. Or possibly a sawtooth or similar. Pure sine wave AC will be a single tone.

Some nice traces here

http://www.planetoftunes.com/sound-audio-theory/types-of-audio-signal.htm

C

 

[Zep]

Umm, not really, no. I mean it *might* be, but probably only if it's a square wave. Or possibly a sawtooth or similar. Pure sine wave AC will be a single tone.

Some nice traces here

http://www.planetoftunes.com/sound-audio-theory/types-of-audio-signal.htm

C

My understanding was that if the voltage was too high it overdrives the speaker and this then means a buzz. Still, I won’t be trying it!

 

[CatmanV2]

My understanding was that if the voltage was too high it overdrives the speaker and this then means a buzz. Still, I won’t be trying it!

Not really. Either you get distortion because the speaker can't move far enough to 'match' the voltage of the signal. If you speaker has a maximum throw of 2cm from neutral adding +5v might use up all that excursion (or -5v, but in the reverse direction). Apply 6v in either direction and it's not going to move in a linear fashion. Might even break stuff.

The other thing that can happen is not the speakers but the amp can suffer from clipping:

Either the input of the amp is too high, or the volume is set too high and the output can't provide sufficient voltage and you end up with a signal that looks like the red one here:
https://www.researchgate.net/figure...udio-signal-suffering-clipping_fig4_313774497

All the peaks are 'clipped' off (compared to the blue) which basically means you're putting DC through your speaker voice coils. Firstly this sounds *HORRID* and secondly you stand a pretty good chance of burning stuff out. Components designed for AC audio really don't like DC...

C

 

[hunta]

(Think I'm more suited to the X-pipe vs. H-pipe debate...)

 

[Zep]

I was thinking of 230v 50hz, which would make an aweful noise and probably release some magic smoke.

As for DC with AC equipment, AC is just DC with a regularly revising polarity, so I suspect short bursts of DC with a suitable voltage wouldn’t be especially harmful.

 

[Contigo]

Cut the back parcel shelf up and stick some Alpine 6x9’s in too...

 

[CatmanV2]

I was thinking of 230v 50hz, which would make an aweful noise and probably release some magic smoke.

As for DC with AC equipment, AC is just DC with a regularly revising polarity, so I suspect short bursts of DC with a suitable voltage wouldn’t be especially harmful.

230v Hz would make lots of smoke and flashes if you plugged it into a normal audio speaker. Very briefly you'd hear a 50Hz tone, pure sine wave, which is something I expect *everyone* on here has heard. Bog standard mains hum.

Most audio equipment will destruct pretty fast if you give it a DC voltage. That's basically a very low frequency square wave which has a lot more energy in it that a square wave.
C

 

[Zep]

230v Hz would make lots of smoke and flashes if you plugged it into a normal audio speaker. Very briefly you'd hear a 50Hz tone, pure sine wave, which is something I expect *everyone* on here has heard. Bog standard mains hum.

Most audio equipment will destruct pretty fast if you give it a DC voltage. That's basically a very low frequency square wave which has a lot more energy in it that a square wave.
C

The first bit I agree with, but DC isn’t a wave at all, if you describe it in terms of a sinusoidal wave form it would have a constant amplitude and no change in polarity. At least that’s what they told me in college. I think.

 

[Ewan]

As for DC with AC equipment, AC is just DC with a regularly revising polarity, so I suspect shorts.

Surely the only shorts with AC DC are the ones Angus wears. No?

 

[CatmanV2]

The first bit I agree with, but DC isn’t a wave at all, if you describe it in terms of a sinusoidal wave form it would have a constant amplitude and no change in polarity. At least that’s what they told me in college. I think.

That's why I tried to say a very low frequency square wave. *very* low indeed. Which will have a *lot* more energy than a sine wave of identical amplitude.

C

 

[Zep]

That's why I tried to say a very low frequency square wave. *very* low indeed. Which will have a *lot* more energy than a sine wave of identical amplitude.

C

I get what you are saying. But here is a video of a man connecting a 9v battery to a speaker to make the point. One click and then, when he disconnects, another click. That’s it - no waveform (square or otherwise) means no buzz.

 

[CatmanV2]

Yeah we're getting a bit confused. It *is* a squareform, well half of one, but only when he connects it and disconnects it

But it still contains a lot more energy than a sine wave / audio signal of the same amplitude.

And for a sub woofer / bass like that, 9V is nothing like the same amplitude (as the audio signal you'd pump into it) So (as ever) my original statement was simplistic. Back of a napkin: assume that's a 300W speaker. At 8 ohms that'd be roughly 30v at 3A (for a sine wave type audio signal). That'd be peak to peak for an audio signal. Now go plug the same speaker into a 3A 30v power source and see how long it lasts.

A tweeter will overheat even faster.

No idea if I'm making any sense

C

 

[FIFTY]

Just about to change the 4 main speakers in my GS ,( im binning the rear shelf speakers ) Am i right in thinking that the black striped speaker wires are the negatives ?

Hey Sparts I did this over last winter pluz a little bit more. I started making notes on which wire does what and I stopped because I realized that I bought these adaptor plugs along with my JL audio speakers:

http://www.caraudiodirect.co.uk/connects2-ct55-ct01-speaker-loom-adaptor-for-alfa-citroen-peugeot

So you won't need to cut off the oem speaker plug. If it helps I made a couple of notes on the rears before I realisdd that I didn't need to work any of it out:

RR
Blue +white = negative
Blue+black = positive
Lr
Orange + black (to solid orange on NIT plug) = Positive

 

[Spartacus]

Im still no closer to finding out if the wires with the black lines on are positive or negative .??

 

[Zep]

Im still no closer to finding out if the wires with the black lines on are positive or negative .??

Connect a battery across the two terminals. If the cone moves outward the +ve is connected to the +ve. If it moves inwards, it isn’t.

 

[Spartacus]

Thank you oh wise one .

 

[conaero]

Ah, theres that vid, I knew I worked it out simper and remember that vid.

Good find Zep.

 

[conaero]

So the next question is, what are the wires...you sill sill have to use a multimeter. You might get lucky and with the hifi on, connect the wires and observe if is shifts up or down.

 

[Zep]

I would have thought that if you make a note of the wires you have disconnected you can work out which is which from where they were connected?

 

[conaero]

I would have thought that if you make a note of the wires you have disconnected you can work out which is which from where they were connected?

Good shout, you obviously had your Weatabix today, where as I did not.