Questions about adding a sub to OEM Bose, 2001 A6 2.7t
06-28-2007, 11:08 PM
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Questions about adding a sub to OEM Bose, 2001 A6 2.7t
Hey guys, I am looking to add a nice 10" sub to my OEM Bose setup. Looking to keep all the same, just add the sub. I have read some say they just used the factory sub amp to power it, and replacing the Bose sub with an aftermarket box. Does anyone know the wattage output of the sub amp & at what ohms? I amlooking to add a 10 that has dual 6ohm coils. So 3ohm net. But I question if it will be powerful enough.
Otherwise, I would go with a line out converter & install my own amp to power it. But I am kinda hoping the OEM Bose might be enough power...
Thanks in advance fellas.
Otherwise, I would go with a line out converter & install my own amp to power it. But I am kinda hoping the OEM Bose might be enough power...
Thanks in advance fellas.
06-29-2007, 05:00 AM
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The dual 4 inch subs are 4 Ohms ea so 2 Ohm equiv. Your 3 Ohm equiv will be OK
for normal listening. If your sub is not very efficient you probably should look for an efficient dual 4 or single 2 Ohm coil. Although I have a tactile transducer from called an I-Beam that provides excellent low frequency extension, I'm thinking of trying out a 10 inch sub for the heck of it. I've already modified the Bose box by cutting off the the enclosure and removing the foam piece in the bottom of the fender well. You could then build a about a .88 cu foot or so sealed cabinet although the shape would be irregular. Bach2h and I have been floating a few ideas around for the install.
Here's few pics:
Amp remounted back into well.
<img src="http://pictureposter.audiworld.com/69962/june_2007_005.jpg">
The Bose assembly where I cut it. Remove the amp first with a T15 torx:
<img src="http://pictureposter.audiworld.com/69962/june_2007_001.jpg">
Another shot at the volume you have to work with. You could also use a free space rated woofer that you could mount with some support to the trunk liner. Possibly use 2 pcs of MDF, one for the speaker and another to provide perpendicular support possibly utilizing a groove and the fender assembly.
<img src="http://pictureposter.audiworld.com/69962/june_2007_002.jpg">
I hope this helps. Good luck.
Here's few pics:
Amp remounted back into well.
<img src="http://pictureposter.audiworld.com/69962/june_2007_005.jpg">
The Bose assembly where I cut it. Remove the amp first with a T15 torx:
<img src="http://pictureposter.audiworld.com/69962/june_2007_001.jpg">
Another shot at the volume you have to work with. You could also use a free space rated woofer that you could mount with some support to the trunk liner. Possibly use 2 pcs of MDF, one for the speaker and another to provide perpendicular support possibly utilizing a groove and the fender assembly.
<img src="http://pictureposter.audiworld.com/69962/june_2007_002.jpg">
I hope this helps. Good luck.
06-29-2007, 05:52 AM
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I doubt it will be powerful enough. You can never have too much wattage.
You can however, have not enough and damage your speakers. I think you'd probably want 200RMS for your 10.
Not talking about crazy thumping either, just clean sound whenever you crank it up a bit and the sub is hitting really low.
Not talking about crazy thumping either, just clean sound whenever you crank it up a bit and the sub is hitting really low.
06-29-2007, 06:09 AM
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What??? How can too few watts damage a speaker? You certainly can have too many watts
to either damage your transducer or your ears. If the Bose sub amp was a digital amp and the impedance was lower than specified your statement could be correct as digital amps are very sensitive at lower than optimized impedances. However it is an analog amp and will not have any issues with a 3 Ohm nominal load as it is designed for a 2 Ohm load.
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06-29-2007, 07:25 AM
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Common misconception: (long)
Wattage measurement is largely misunderstood. Sure, an amplifier can be capable at putting out say, "500 watts" but the level of distortion may be extremely high. This is what damages speakers. A "200 watt" amplifier that has very low distortion specs will sound better and have less chance of blowing speakers.
It must also be undersstood that the measure off wattage is largely misused. Crappy amps will claim "500 Watts" when this is really just a measure of their capabilities at the highest possible, momentary, distortion-ridden peak (it's called peak power, is very irrelevant and it is ususally measured in the higher frequencies that don't require much current). If you look at very high quality amplifiers, you'll see that it becomes extremely expensive to purchase the higher "wattage" models. This is because the output is measured across the entire frequency spectrum and is averaged. Very low frequencies require tremendous current and this is what defines a quality amplifier (much more absolutely than "wattage") A good rule of thumb determination of an amplifiers quality and ability to play loudly at low distortion can be had by looking at its "wattage" capability at 8 ohms vs. 4 ohms. If the "wattage" number fully doubles at 4 ohms, the chances are very, very good that it's going to be a superb amplifier. A 50 watt amp that fully doubles will sound far better, play more loudly and be much safer for your speakers than a 500 watt amp that does not.
It must also be undersstood that the measure off wattage is largely misused. Crappy amps will claim "500 Watts" when this is really just a measure of their capabilities at the highest possible, momentary, distortion-ridden peak (it's called peak power, is very irrelevant and it is ususally measured in the higher frequencies that don't require much current). If you look at very high quality amplifiers, you'll see that it becomes extremely expensive to purchase the higher "wattage" models. This is because the output is measured across the entire frequency spectrum and is averaged. Very low frequencies require tremendous current and this is what defines a quality amplifier (much more absolutely than "wattage") A good rule of thumb determination of an amplifiers quality and ability to play loudly at low distortion can be had by looking at its "wattage" capability at 8 ohms vs. 4 ohms. If the "wattage" number fully doubles at 4 ohms, the chances are very, very good that it's going to be a superb amplifier. A 50 watt amp that fully doubles will sound far better, play more loudly and be much safer for your speakers than a 500 watt amp that does not.
06-29-2007, 08:58 AM
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Re: Common misconception: (long)- long too
Correct. This is why the only true measure of an amp is RMS power in Watts measured over the operating frequency with a specified impedance, THD, IMD etc.. etc... However, the case being made above was the lower power Bose sub woofer amp would damage a higher power rated speaker is just not true. Especially since the speaker he mentions is 3 Ohms nominal. Since the Bose subs are (2) 4 ohm transducers in parallel the nominal impedance is 2 Ohms. As you know, one measure of power is Voltage Squared/impedance. Since the 3 Ohm transducer will never allow the Bose amp to reach full output, there's no way it could damage a higher power rated speaker. It just will not reach saturation.
The only way damage can occur is if the impedance of the transducer is less than the rating of the amp. This is viewed as a short ckt by the amp and it will clip when pushed and possibly be damaged or create voltage spikes that could damage a transducer as the wave shape of the energy could be quite sharp although in short duration until the PWM's on a Class D or the output transistors on a linear amp blow. The possible speaker damage would be a function of how well the voice coil structure could sustain the energy and/or cone excursion from such a transient.
An efficient /higher sensitivity sub woofer will work just fine sonic as well as electrical with this Bose linear sub woofer amp at 2 - 4 Ohms. That's my story and I'm sticking to it.
The only way damage can occur is if the impedance of the transducer is less than the rating of the amp. This is viewed as a short ckt by the amp and it will clip when pushed and possibly be damaged or create voltage spikes that could damage a transducer as the wave shape of the energy could be quite sharp although in short duration until the PWM's on a Class D or the output transistors on a linear amp blow. The possible speaker damage would be a function of how well the voice coil structure could sustain the energy and/or cone excursion from such a transient.
An efficient /higher sensitivity sub woofer will work just fine sonic as well as electrical with this Bose linear sub woofer amp at 2 - 4 Ohms. That's my story and I'm sticking to it.
06-29-2007, 07:50 PM
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To few damages more speakers than anything. For the simple reason that the amp is always
overloaded and produces too much distortion or square waves which damage the speaker. In the case the higher impedance load, this might prevent the amp from being over driven. It will also prevent the speaker from getting enough juice to sound good. A low powered sub never sounds good. It will sound thumpy instead of tight and controlled. On top of all this, Bose is well known for using low budget drivers and then tweaking the electronicss for semi-flat response. So driving anything by Bose amps is going to sound bad. The tweaks by Bose will come thru as overdone by a speaker designed to have flat response.