Bose Premium - possible to replace stock sub, keep all else the same?

[MichaelSE]

I'd like a little bit more bass with my stock Bose Premium system but would prefer to keep everything as simple and stock as possible because I'm kind of dumb when it comes to electrics and wiring. I'm wondering if it's possible to simply remove the wires from the stock sub and run them to a 8" or 10" sub box behind the 3rd row.

i.e. will the stock Bose Premium amp put out enough to power a slightly larger sub, or will I need a new amp entirely to power one?

A user on here told me that it would work fine as long as the ohm rating of the new sub was the same as the ohm rating on the Bose sub.

 

[MichaelSE]

Gonna bump this back up to the top, someone here has to know.

 

[Rocket Man]

You can do that but it won't be much louder without more power, as in a new amp. You do need to keep it the same ohms. The stock amp is matched to the sub as far as power output so just a bigger sub won't do much. I tried that but ended up adding a new mono amp as well as a new head unit so I had a sub output. It also made the other speakers sound better. But then I ended up replacing those too. Once you start, you know how it goes.

 

[scott6760]

Typically the Bose speakers run a very low impedance, such as 1-2 ohms. Most aftermarket speakers are 4 ohms, some are 2 ohms. Usually an amp is perfectly fine running a higher impedance than it's designed or rated for. The problems come when you try to connect a speaker with too LOW of an impedance rating. So, you should be fine connecting a 4 ohm speaker to the factory amp.

BUT, most amps put out less power into a higher impedance load. So even though you might replace it with a 'better' speaker you will probably be giving the new speaker less power than the original Bose speaker.

There's also the sensitivity rating to consider. If you can find a speaker with a higher sensitivity than the OEM sub then you could have more output.

As you can see, it very much depends on a number of factors.


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[Rocket Man]

Typically the Bose speakers run a very low impedance, such as 1-2 ohms. Most aftermarket speakers are 4 ohms, some are 2 ohms. Usually an amp is perfectly fine running a higher impedance than it's designed or rated for. The problems come when you try to connect a speaker with too LOW of an impedance rating. So, you should be fine connecting a 4 ohm speaker to the factory amp.

BUT, most amps put out less power into a higher impedance load. So even though you might replace it with a 'better' speaker you will probably be giving the new speaker less power than the original Bose speaker.

There's also the sensitivity rating to consider. If you can find a speaker with a higher sensitivity than the OEM sub then you could have more output.

As you can see, it very much depends on a number of factors.


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You can blow an amp with too high of impedance too. It's like trying to force twice the water through the same size hose. Too much impedance (resistance) can cause an amp to overheat and burn up. Besides if it's rated for 2 ohms and you throw a 4 ohm speaker the output is cut in half, relatively speaking. Yes you can get a sub with a higher efficiency/ sensitivity rating but you're still not going to be impressed believe me. Subs require a lot of power, unlike mids and tweeters. They are what require the huge amps and battery/ alternator setups in audio competitions. The rest of the systems require a very small percentage of the total power. In order to get more bass, it's not the size of the sub nearly as much as the size of the amp pushing it.

 

[scott6760]

You can blow an amp with too high of impedance too. It's like trying to force twice the water through the same size hose.

The proper analogy would be 'forcing the same amount of water through a hose with half the diameter'.

Too much impedance (resistance) can cause an amp to overheat and burn up.

In extreme cases, too much resistance can be harmful but we're talking about nominal 4 ohms vs. 1 ohm. The impedance of any speaker varies with frequency. That's why it's called impedance and not resistance. A speaker with a rated 1 ohm NOMINAL impedance very likely sees swings of up to 20 ohms or greater throughout its passband. The tuning of the enclosure can also greatly affect impedance. If you're bored do a Google search for 'speaker impedance curve'.

Besides if it's rated for 2 ohms and you throw a 4 ohm speaker the output is cut in half, relatively speaking.

Yes, I said that in my post, and you even quoted it.

Yes you can get a sub with a higher efficiency/ sensitivity rating but you're still not going to be impressed believe me....In order to get more bass, it's not the size of the sub nearly as much as the size of the amp pushing it.

This statement couldn't be further from the truth. Doubling the power will provide a 3dB increase. This rule applies to tweeters, mids, subs, it doesn't matter. If you use an efficient enclosure you can gain 6-12dB (or greater) of sensitivity, therefore greatly increasing your maximum output without increasing the power at all.

Can you get more output by increasing the power? Sure, but you will very quickly hit a point of diminishing returns. Let's say your sub makes 120dB with 1000 watts. You could double the power to 2000 watts and still only make 123 dB. Let's double the power again, now you're making 126dB but it takes 4000 watts and your trunk is probably on fire. Or, you could use a more efficient sub and make 126dB with the original 1000 watts. Which would you rather have?



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[Rocket Man]

I'm not gonna argue with you. I installed car stereo for a few years and I know what I'm talking about. You have to realize he has a factory Bose multichannel amp, not an aftermarket monoblock. You're right about my analogy of the water and hose though, I realized that right after I posted it. I stand by the rest of what I stated. I'm trying to help the OP, not get into an argument. Since you're new, I'll just say welcome to the forum.

 

[MichaelSE]

Thanks for all the replies.

I tried that but ended up adding a new mono amp as well as a new head unit so I had a sub output.

So just so I understand correctly, is the sub output from my Bose amp already "powered" for lack of a better word? Would this make it impossible to install a mono amp on for another sub on that channel only?

 

[Rocket Man]

Thanks for all the replies.



So just so I understand correctly, is the sub output from my Bose amp already "powered" for lack of a better word? Would this make it impossible to install a mono amp on for another sub on that channel only?

It only has speaker level (aka high level) low frequency audio. There isn't a low level ( using RCA jacks) output for an amp but there are line level adapters to convert that signal to low level or some amps have high level inputs. Then you need a way to turn on the amp, so you need to find the amp turn on wire in the radio harness as well as run the constant power and ground to the amp. It will work, though. You won't have as much control over the sub as an aftermarket head unit which would have settings for the sub itself as opposed to just a bass setting. You can make level adjustments on the amp itself though, and most amps have crossover settings etc as well.

 

[MichaelSE]

It only has speaker level (aka high level) low frequency audio. There isn't a low level ( using RCA jacks) output for an amp but there are line level adapters to convert that signal to low level or some amps have high level inputs. Then you need a way to turn on the amp, so you need to find the amp turn on wire in the radio harness as well as run the constant power and ground to the amp. It will work, though. You won't have as much control over the sub as an aftermarket head unit which would have settings for the sub itself as opposed to just a bass setting. You can make level adjustments on the amp itself though, and most amps have crossover settings etc as well.

Sounds complicated, waaaay above my experience level How much do you think it would be for an audio shop to do all that, if I buy the amp and sub?