Brucee,
where did you get Phass in WA ?
0
how to get Car Sounds Louder?
Started by [JOGER], Nov 12 2004 06:58 AM
23 replies to this topic
#17
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Posted 16 November 2004 - 10:23 PM
not from WA actualy,my bro in melb get it for me
#18
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Posted 16 November 2004 - 11:50 PM
Buy another set of ears, coz you must be dead as a doornail lol
Your stereo looks loud
:thumb:
Your stereo looks loud
:thumb:
QUOTE (RYDFMX @ Dec 1 2008, 09:56 PM)
it reads 154.3 haha i made a port today bit over twice the length and it plays alot lower now but no where near as loud to the ear as bretts 121 that is insane.
#19
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Posted 17 November 2004 - 09:51 AM
Mobi said:
Brucee,
where did you get Phass in WA ?
where did you get Phass in WA ?
www.cesarenterprise.com
they are Western Australia base company. Check them out.
#20 Guest_slavon_*
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Posted 24 November 2004 - 12:25 PM
'[JOGER said:
']It's quite loud at the moment.
But with P9R I have to listen at 10 DB to make my ear happy. But from my point of view. It should be louder than that, at 10 DB.
Need more mid bass. And So on.
~
But with P9R I have to listen at 10 DB to make my ear happy. But from my point of view. It should be louder than that, at 10 DB.
Need more mid bass. And So on.
~I would be careful with the RE-50. I had it in my car as well (sadly the car was recently stolen) and what is initially perceived as low volume is actually the lack of speaker distortion (due to the constant current design of the RE amplifier). The result is a clear sound that does not hurt or exhaust the ears. While this is a wonderful quality of the amp in terms of sound, it can be harmful for your eardrums since you don't realize how loud the music really is.
-Slavon
#21
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Posted 25 November 2004 - 01:07 PM
slavon said:
I would be careful with the RE-50. I had it in my car as well (sadly the car was recently stolen) and what is initially perceived as low volume is actually the lack of speaker distortion (due to the constant current design of the RE amplifier). The result is a clear sound that does not hurt or exhaust the ears. While this is a wonderful quality of the amp in terms of sound, it can be harmful for your eardrums since you don't realize how loud the music really is.
I disagree.
Why do you suggest the design RE-50 would produce less speaker distortion, for a given amount of power?
I would say that due to the high output impedance design, it would actually cause a frequency response distortion, unless the speaker has a flat impedance curve.
The RE-50 doesn't actually produce a true constant current ouput, it just acts more like one (due to the high output impedance) when compared to a normal Hi-Fi amplifier.
I would say that it isn't as loud (that is not to say that it cannot play loudly at all) compared to some other amplifiers, simply because it doesn't output as much power as those other amplifiers.
If in doubt, do a search and then ask questions!
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#22 Guest_slavon_*
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Posted 26 November 2004 - 08:38 AM
Bassaholic said:
I disagree.
Why do you suggest the design RE-50 would produce less speaker distortion, for a given amount of power?
I would say that due to the high output impedance design, it would actually cause a frequency response distortion, unless the speaker has a flat impedance curve.
The RE-50 doesn't actually produce a true constant current ouput, it just acts more like one (due to the high output impedance) when compared to a normal Hi-Fi amplifier.
I would say that it isn't as loud (that is not to say that it cannot play loudly at all) compared to some other amplifiers, simply because it doesn't output as much power as those other amplifiers.
Why do you suggest the design RE-50 would produce less speaker distortion, for a given amount of power?
I would say that due to the high output impedance design, it would actually cause a frequency response distortion, unless the speaker has a flat impedance curve.
The RE-50 doesn't actually produce a true constant current ouput, it just acts more like one (due to the high output impedance) when compared to a normal Hi-Fi amplifier.
I would say that it isn't as loud (that is not to say that it cannot play loudly at all) compared to some other amplifiers, simply because it doesn't output as much power as those other amplifiers.
Usually the speakers system are voltage-driven:an amplifier with very low output impedance is used to keep the voltage applied to the speaker at a constant level.(Do not forget that force applied to the voice coil directly proportional to the CURRENT AND ONLY CURRENT).So this has folloving consequences:
1.The load(loudspeaker) is reactive and not linear,as a result the current in the voice coil become distorted.But current is converted into acoustic pressure,the pressure (what we hear) is distorted as well.
2.There is a very strong feedback: in fact, according with Lenz law, during the operation of a loudspeaker at the ends of the voice coil there is a voltage that opposes to the cause that has generated it. Since the voice coil is connected through low resistance cables to an amplifier with low output impedance [Rout], we have a great inverse current [i'], that is a very strong feedback that brings the membrane to the zero position.
3.This force due to the feedback current is proportional to membrane velocity. Whereas the force of elastic spring due to suspensions is proportional to the shift from the rest point. The contemporary presence of two different forces gives non-linearity and therefore distortion
Let take a look to the current driving:
1.Now an amplifier try to keep current at constant level and voltage become distorted,but it does not matter ,becouse acoustic pressure is proportional to the current.
2.The inverse current due to feedback can be canceled, since the very high value of the output impedance inhibits inverse current circulation.
3.By blocking inverse current circulation, non-linearity due to the contemporary presence of different forces can be eliminated.
Ok guys the above is only theory so for me that actual personal experience of how this sounds is what matters.I had RE-50 in my car.....although it's power is limited (I wouldn't recommend it for SPL comp ;]) I stand by my earlier statement about the sound being very clear and undistorted and this possibly being perceived as low volume.
-Slavon
#23
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Posted 26 November 2004 - 05:43 PM
i can't wait to read bass's reply... lol 
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#24
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Posted 27 November 2004 - 03:21 AM
Yes, speakers are reactive and that is normally why a low output impedance is preferable.
The main causes of impedance rise are due to:
The inherent voice coil inductance - the fact that you have a coil of wire and also that it has a metal pole piece through the centre, will mean that there will generally be significant inductance. The "distortion" that this results in, is roll-off of the upper frequency response. Naturally this factor (and assuming a constant voltage) is already considered when designing the driver and designing the crossover.
Secondly the resonance effect of the suspension/moving mass will result in a 2nd order roll-off at low frequencies (assuming it is in a 2nd order enclosure - sealed/infinite baffle) and a significant impedance peak at the Fc of the system. The ripple in the response will depend on the damping (Qtc) of the system. (assuming constant voltage) More damping (lower Q) will actually result in more impedance rise at the resonant frequency.
The current tends to be more constant due to the significant losses through the output impedance.
You can easily do the math to get an understanding, ie
Voltage at speaker = Voltage before losses x (Impedance of speaker / (Impedance of speaker + Output impedance))
Then use Current = Voltage divided by Resistance.
So if you had a voltage of 30v, a speaker impedance of 4 ohm (at a particular frequency) and an output impedance of 0.1 ohm,
Vspk = 30 x (4/4+0.1)
Vspk = 29.3v (approx)
Ispk = 29.3/4
Ispk = 7.32 amps (approx)
If the impedance at a different frequency was 45 ohm then:
Vspk = 30 x (45/45+0.1)
Vspk = 29.9v (approx)
Ispk = 29.9/45
Ispk = 0.66 amps (approx)
If the output impedance was higher, say 20 ohm
Vspk = 30 x (4/4+20)
Vspk = 5v
Ispk = 5/4
Ispk = 1.25 amps
Vspk = 30 x (45/45+20)
Vspk = 20.8v(approx)
Ispk = 20.8/45
Ispk = 0.46 amps (approx)
So the current isn't necessarily constant, but the difference in current is much less.
Acoustic pressure is proportional to current, but you also need to take into account the efficiency - if the current drops (due to impedance rise at resonance), but if the energy required to maintain that pressure also drops due to resonance, then the net result is a smooth response. Unfortunately, if there is a high output impedance, the current will not drop enough in proportion to the rise in impedance therefore the output level at the resonant frequency will be accentuated. A high output impedance will not magically stop the speaker resonance.
Here is an example of the effect of significant output impedance on a midrange. (in this case, 8 ohm nominal and series resistance of 20 and 40 ohms) The magnitude of the effect in a real world case depends on the impedance curve of the driver vs the impedance curve of the amplifier (including series resistance, ie that of the speaker wire).
The main causes of impedance rise are due to:
The inherent voice coil inductance - the fact that you have a coil of wire and also that it has a metal pole piece through the centre, will mean that there will generally be significant inductance. The "distortion" that this results in, is roll-off of the upper frequency response. Naturally this factor (and assuming a constant voltage) is already considered when designing the driver and designing the crossover.
Secondly the resonance effect of the suspension/moving mass will result in a 2nd order roll-off at low frequencies (assuming it is in a 2nd order enclosure - sealed/infinite baffle) and a significant impedance peak at the Fc of the system. The ripple in the response will depend on the damping (Qtc) of the system. (assuming constant voltage) More damping (lower Q) will actually result in more impedance rise at the resonant frequency.
Quote
1.Now an amplifier try to keep current at constant level and voltage become distorted,but it does not matter ,becouse acoustic pressure is proportional to the current.
2.The inverse current due to feedback can be canceled, since the very high value of the output impedance inhibits inverse current circulation.
3.By blocking inverse current circulation, non-linearity due to the contemporary presence of different forces can be eliminated.
2.The inverse current due to feedback can be canceled, since the very high value of the output impedance inhibits inverse current circulation.
3.By blocking inverse current circulation, non-linearity due to the contemporary presence of different forces can be eliminated.
The current tends to be more constant due to the significant losses through the output impedance.
You can easily do the math to get an understanding, ie
Voltage at speaker = Voltage before losses x (Impedance of speaker / (Impedance of speaker + Output impedance))
Then use Current = Voltage divided by Resistance.
So if you had a voltage of 30v, a speaker impedance of 4 ohm (at a particular frequency) and an output impedance of 0.1 ohm,
Vspk = 30 x (4/4+0.1)
Vspk = 29.3v (approx)
Ispk = 29.3/4
Ispk = 7.32 amps (approx)
If the impedance at a different frequency was 45 ohm then:
Vspk = 30 x (45/45+0.1)
Vspk = 29.9v (approx)
Ispk = 29.9/45
Ispk = 0.66 amps (approx)
If the output impedance was higher, say 20 ohm
Vspk = 30 x (4/4+20)
Vspk = 5v
Ispk = 5/4
Ispk = 1.25 amps
Vspk = 30 x (45/45+20)
Vspk = 20.8v(approx)
Ispk = 20.8/45
Ispk = 0.46 amps (approx)
So the current isn't necessarily constant, but the difference in current is much less.
Acoustic pressure is proportional to current, but you also need to take into account the efficiency - if the current drops (due to impedance rise at resonance), but if the energy required to maintain that pressure also drops due to resonance, then the net result is a smooth response. Unfortunately, if there is a high output impedance, the current will not drop enough in proportion to the rise in impedance therefore the output level at the resonant frequency will be accentuated. A high output impedance will not magically stop the speaker resonance.
Here is an example of the effect of significant output impedance on a midrange. (in this case, 8 ohm nominal and series resistance of 20 and 40 ohms) The magnitude of the effect in a real world case depends on the impedance curve of the driver vs the impedance curve of the amplifier (including series resistance, ie that of the speaker wire).
If in doubt, do a search and then ask questions!
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