"standby" second sub... Would this make sense? (second w7 in differnet size)

[Range Rover W7 10+ year member]

I have a Range Rover with a factory head unit, JL Audio 1000/1, 2 farad Fosgate digital cap and JL 10w7 in a custom fiberglass enclosure. I'm adding a JL cleansweep processor tomorrow and most likely a JL 300/4 and upgrading the mids and tweeters in the near future. I just stumbled across a JL 13w7 in a ported box for SUPER cheap. I'm curious if I could add this as a second sub in my truck for the occasions that I want so earth shaking bass? Would it compliment the sound of the 10 (which I love for the tight bass), but the land rover is constructed so well you can barely hear the music outside of the vehicle. I also want to be able to "feel" the bass more sometimes.... I'd keep the enclosure in my trunk but would like the fact that I can remove it easily when i need the trunk space and would be able to keep the current setup for less extreme days.

So whats the consensus? Thank you for your time.

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[misfit138 5,000+ posts]

It's a stupid, stupid idea.

Oh, and I didn't know Land Rover built a vehicle with a trunk...

 

[Range Rover W7 10+ year member]

Thanks for your response... I guess I've just been wanting a louder system in some circumstances, and don't want to abandon the sealed 10w7 enclosure which is dialed in perfectly and essentially built into the boot. It isn't large enough to handle the 13w7 and I really prefer the sound of 10's more on a day to day basis.... I occasionally just want more...

And on a side note, Initially the 10w7 was the only jl component I had.... I've just run across a ton of stellar deals on their products for great prices used locally...

What problems would I run into by adding this second removable 13"? If I ended up liking the sound of it better, I'd have a new enclosure built and abandon the 10... But if I did attempt it, would should I expect?

and I apologize for calling the rear cargo compartment a trunk... clearly it failed to convey the region of the vehicle i was referencing.

 

[misfit138 5,000+ posts]

Basically, mixing different sized subwoofers is frowned upon in damn near any circumstance. In a nice Range Rover, it'd be a dirty shame to do something like this. It's not necessarily wrong, it's just pointless. Why pack around an extra subwoofer if it isn't being used? The benefits seem miniscule at best in my opinion. If you want louder bass, either add a second 10" W7 or upgrade to the 13.5". There's absolutely no reason to have both.

I don't know how educated you are on the subject of car audio, but if you like the sound of a 10" you'll like the sound of a 13.5" too. The 13.5w7 can be used in a relatively small sealed enclosure, much like the 10" model. The W7 just has more cone area and greater power handling. That means it'll be louder, but it has very little to do with the overall "quality" of the sound the subwoofer makes.

Either step up to a pair of W7's and dial back the bass when you don't feel like blasting the subs, or swap the 10w7 you already have for the 13.5". Having both at once makes little sense...

 

[audioholic 5,000+ posts]

Mixing sub sizes seems to be a popular topic around here again lately. Barring the use of a relatively complex crossover network that separated each speaker's frequency response (like the 13.5 runs 20-50hz, the 10 runs 50-80hz, with the proper slopes), then no, its generally a bad idea to mix different sub sizes. Different sized subs, even of the same make/model, will have different frequency responses. Trying to couple two subs who do not react exactly the same means over all frequency response will be erratic and unpredictable. Some freqs will be artificially boosted by sound wave reinforcement, other freqs will be artificially diminished due to cancellation. This is bad for sound quality as we generally want a smooth and predictable response to make tuning the system easier.

misfit is correct in that there is no particular sound associated with a particular speaker diameter. 10's dont sound a certain way, while 15's sound different. As I said above, different sized subs, even of the same make/model, will have different freq responses. But that does not mean 15's will always have a lower Fs than 10's. A 10" sub can be (and is) built with a lower Fs than many 15" subs, as that mainly comes down to suspension design. Consequently, its not unheard of in the home audio world to have a 15" speaker that plays full-range. So clearly cone diameter alone is not the sole factor in frequency response. Larger cones do mean more air displacement, which does mean more ability for greater output in the lowest frequencies, but mating enough smaller drivers to reach the same cone area (and excursion) will give the same potential for air displacement and low freq output (given similar Fs specs).

If anything, the 13.5 has the potential for better sound quality than the 10 because due to having (a lot) more cone area, the cone does not have to move as far to displace the same amount of air and reach the same output level as the 10 would need to. Less cone excursion to reach the same output level means the coil travels less distance outside the gap, which means less BL distortion from loss of motor control. W7's are BL optimized so this is not as big of a deal as it would be for more conventional motor topologies, but its still worth mentioning.

 

[hispls 5,000+ posts]

frequency response will be erratic and unpredictable. Some freqs will be artificially boosted by sound wave reinforcement, other freqs will be artificially diminished due to cancellation. This is bad for sound quality as we generally want a smooth and predictable response to make tuning the system easier.

Unpredictable is the key. It's rather a big gamble that all the variables will add up in your favor for a "good" sound when mix-matching speaker systems. I'd say you'd need to have some powerful EQ capabilities or a lot of patience and test equipment to do something like this and have it come out right. Definitely can be done and definitely might even work just as a drop in, but from a SQ standpoint it's more likely to be an accoustic failure than help. I used to do this stuff way back in the day and as often as not mix-matching would hurt more than help. Though sometimes it worked great and I was very happy. The price of a W7 may or may not be worth the gamble, then again if you buy it at a great price, you can always play around and if it doesn't work sell it and recoup most of the money.

 

[Range Rover W7 10+ year member]

Thank you all so much for you helpful advice. I have determined that I wouldn't "add" a 13w7 to the system so much as have it as a second option. I would unplug the 13 when playing the 10 and vice versa. I could have 2 totally different enclosure types for entirely different sounds/purposes. I've debated adding a second 10w7 instead, however feel that having both the 13 and the 10 and determining which sound I prefer and putting the other in my second vehicle. I like the sub to add to the music, not just rattle my brain. Granted the 10w7 is really loud and sounds great, I would like to "feel" the bass a bit more (lower frequency) without the need to increase the volume as much. I also have to admit that I'd occasionally like to be obnoxious and turn heads from outside the vehicle (enter 13w7) However on a day to day basis that isn't a primary goal.