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I am not an audiophile and dont know anything about impedance other than that its a nuisance. I dont know the difference between Watts, Ohms or an other terms used by the guys who love this stuff. I do however have ears and i was actually astonished at the difference changing the stock speakers on my bagger for Alpine 410's made.
After reading about it on this forum I decided that any improvement on the stock speakers has to be good. I also wasnt expecting much change as I wasnt going to stuff the speaker boxes with Dynamat (sounds dangerous actually) or do any other modification at all.
I installed the left one first and found it super easy, less than 45 minutes and most of that taken up by trying to open the glued shut box. After I renstalled it and before taking out the other one I tested it. So both speakers were playing the identical thing at the exact same volume setting.
At first thought I screwed something up because the stock one didn't seem to be working. I couldn't hear it at all until I put my ear nearer to it as it was being completely drowned out by the newly installed 410. I was shocked at the difference, not only in volume but in lack of distortion and general sound quality. I installed the other (quicker as now I had the opening of the glued box dialed) and I am thrilled with the improvement this cheap ($50 from Crutchfield), quick and easy change made. I cant understand why anyone would keep the stock toy speakers, even if you do only use them for listening to AM, road reports or emergency notices.
 

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I am not an audiophile and dont know anything about impedance other than that its a nuisance. I dont know the difference between Watts, Ohms or an other terms used by the guys who love this stuff. I do however have ears and i was actually astonished at the difference changing the stock speakers on my bagger for Alpine 410's made.

After reading about it on this forum I decided that any improvement on the stock speakers has to be good. I also wasnt expecting much change as I wasnt going to stuff the speaker boxes with Dynamat (sounds dangerous actually) or do any other modification at all.

I installed the left one first and found it super easy, less than 45 minutes and most of that taken up by trying to open the glued shut box. After I renstalled it and before taking out the other one I tested it. So both speakers were playing the identical thing at the exact same volume setting.

At first thought I screwed something up because the stock one didn't seem to be working. I couldn't hear it at all until I put my ear nearer to it as it was being completely drowned out by the newly installed 410. I was shocked at the difference, not only in volume but in lack of distortion and general sound quality. I installed the other (quicker as now I had the opening of the glued box dialed) and I am thrilled with the improvement this cheap ($50 from Crutchfield), quick and easy change made. I cant understand why anyone would keep the stock toy speakers, even if you do only use them for listening to AM, road reports or emergency notices.


the speakers are rain proof?
Thank’s


Envoyé de mon iPhone en utilisant Tapatalk
 

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Discussion Starter #4
No not waterproof, but the speaker grills have some kind of rubber barrier inside that stops water unless its flooding. I quick pass or two under the kitchen tap let through just a couple of drops.
 

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A couple of things will affect the volume. To use some 'technical voodoo'... The impedance will make a difference. I see the Alpines are 4 ohm. If the stock speakers are 6, 8 or even 16 (unusual for speakers but common in headphones) the Alpine's sound will be louder. Then there is the sensitivity. Alpines are 87db /watt at one meter which isn't especially 'loud' but maybe the stock speakers are a scrap lower.

I would suspect the main difference comes from the impedance difference. Hopefully the amplifier will not mind the lower resistance of the Alpines (if they are).

I actually like the idea of this a swap and may do this myself.

Cheers,

Derek
 

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The stamp on the back of the stock toy one says 4 ohm (looks like it should be an ohm sign) as well.
Yup, that's a 4 ohm speaker. Must be a lower sensitivity than the Alpines.

Do be careful about running at or near full volume. Usually you would pair a LOWER wattage speaker with an amp and run the amp within the range of the speaker's capability. If the speaker can handle more than the amp, then the temptation is to run the amp at its high end and then signal distortion can blow a speaker. This is especially true with sound systems but I suspect applies in this case as well.

Cheers,

Derek
 

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I am not an audiophile and dont know anything about impedance other than that its a nuisance. I dont know the difference between Watts, Ohms or an other terms used by the guys who love this stuff. I do however have ears and i was actually astonished at the difference changing the stock speakers on my bagger for Alpine 410's made.
After reading about it on this forum I decided that any improvement on the stock speakers has to be good. I also wasnt expecting much change as I wasnt going to stuff the speaker boxes with Dynamat (sounds dangerous actually) or do any other modification at all.
I installed the left one first and found it super easy, less than 45 minutes and most of that taken up by trying to open the glued shut box. After I renstalled it and before taking out the other one I tested it. So both speakers were playing the identical thing at the exact same volume setting.
At first thought I screwed something up because the stock one didn't seem to be working. I couldn't hear it at all until I put my ear nearer to it as it was being completely drowned out by the newly installed 410. I was shocked at the difference, not only in volume but in lack of distortion and general sound quality. I installed the other (quicker as now I had the opening of the glued box dialed) and I am thrilled with the improvement this cheap ($50 from Crutchfield), quick and easy change made. I cant understand why anyone would keep the stock toy speakers, even if you do only use them for listening to AM, road reports or emergency notices.
Just to be clear, did you end up installing the Dynamat or not?... Just curious of the sound difference..
 

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A couple of things will affect the volume. To use some 'technical voodoo'... The impedance will make a difference. I see the Alpines are 4 ohm. If the stock speakers are 6, 8 or even 16 (unusual for speakers but common in headphones) the Alpine's sound will be louder. Then there is the sensitivity. Alpines are 87db /watt at one meter which isn't especially 'loud' but maybe the stock speakers are a scrap lower.

I would suspect the main difference comes from the impedance difference. Hopefully the amplifier will not mind the lower resistance of the Alpines (if they are).

I actually like the idea of this a swap and may do this myself.

Cheers,

Derek
I'm not sure that is quite right, all else equal.

While the current and power delivered by the amp does double when you drop from 8 to 4 ohms, the strength of the magnetic field created by the coil doesn't. The strength of the magnetic field is directly proportional to the length of the wire in the voice coil. Similarly, the impedance introduced by the wire is also directly proportional to the length of that wire. So, as you reduce the length of the wire (or increase its thickness), both the impedance and the magnetic force drop. But, as the impedance drops, the current goes up. The magnetic force is also proportional to the current. So, the increased current obtained from reducing the impedance exactly offsets the corresponding loss of magnetic force. So, a 4 ohm and 8 ohm speaker of the same sensitivity should produce the same output.
 

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OK, just did some deeper research on the subject. It seems that other variables conspire to prevent a higher volume from a 4 ohm vs 8ohm speaker. It seems that although the current is theoretically doubled, the amp may not be able to deliver this across the entire frequency range due to heat dissipation, amp topology and other factors. A very helpful explanation is given in this link for anyone interested. So you are right and I am wrong (though not sure your explanation aligns with the discussion in the link - perhaps just my misunderstanding).

https://forum.audiogon.com/discussions/4ohm-8ohm-speakers-and-output-power
See Sean's response.

But bottom line, both speakers were 4 ohm (stock and Alpine) so presumably, the higher volume is due to either sensitivity (SPL) or somewhat different characteristics of the speaker coil and cone design. Or maybe the frequency response of the Alpine has a hump in the most noticeable frequency range - leading to a perception of greater loudness?

But thanks for the correction and the gracious way you made it.

Cheers,

Derek
 

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The answer to the difference between these two 4 ohm speakers is probably in the photos on the OP's post. Look at the magnet weight and the mechanical travel of the cone of the Alpine speaker. That used to be called the "motor" of the speaker and a larger, more powerful magnet means better control of the cone. If I remember my speaker design days, the impedance of the speaker varies with frequency, so it can be between say 2-10 ohms (I made those numbers up for example). So if the Alpine has a lower impedance in the right frequencies it will allow the amp to pass it more power.


However a speaker is not simply an electrical circuit. Since the amount of the voice coil in the magnetic field changes the impedance, the movement of the cone (and attached voice coil) while pumping air comes into play. A stiffer, higher spec cone can move air more efficiently and so theoretically play louder. Note also how much deeper the Alpine speaker is. That is adding surface area to the cone without increasing the diameter of the speaker. The power is directly proportional to the amount of air the cone can move, so a larger cone surface area coupled with more travel equals more acoustic power.


I can't tell from the photos but it looks like the Alpine has a proper dome tweeter. This driver would produce the high frequencies much more efficiently than a single, larger cone. To a large extent, the "character" of a speaker is more defined by the higher frequencies than the lower ones (actually technically mid-range frequencies).


It's a lot more complicated than all of that, but that's generally what's going on IMHO. This however brings up a bigger mystery. Did BMW really ship the poor performing OEM radio over a $40 speaker?
 
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