10 replies to this topic

[Poohbear]

My car (smallish two door sports) has a 10 inch cutout on the rear parcel shelf for a woofer install. Apparently expecting a free air unit.
I am looking to add a SQ woofer and mono amp.

There is very limited boot space and as I travel frequently, it is usually full of equipment and suitcases. So no room for big sub boxes in the boot and there isn't any clearance under the seats either.

I am looking to add base to my front stage which are Seas Reference splits.
Any recommended woofers that work well in free air (unboxed)?
Big volume is not an issue for me as long as the bass is there.
Budget is 2K.

[scraverX]

There are subs that model reasonably in an infinite baffle (free air) configuration but I can't really make recommendations on this as I don't know a lot about Sub setups.
You may need to reinforce the parcel shelf (just a sheet of MDF wold be enough I think) to get decent results.

Another option would be a small enclosure built under the shelf.

I'm sure others could give you more information then I can.

[cm_ls1]

If there are any left on ebay - rvhifi had some a while back - matrix elite sub , phenomenal in infinite baffle config, dont need alot of power either in ib setup.

Try and fit a 12 though or even a 15 if you want to go real low!

Although be prepared to dynamat the whole boot, and make a strong parcel shelf mount.

2k is a bit overkill for amp and sub

Edited by cm_ls1, 16 March 2011 - 08:01 PM.

[br85]

Very few subs can handle their rated power in free air without bottoming out. A 1000WRMS woofer, when used in free air, still has a thermal power handling of 1000W but will likely smash the voice coil at much less power (A lot of drivers approximately 20% of their rated power). The only exception is where the spider and surround are VERY stiff, which is generally not any form of sq sub anyway.

I'd steer clear of anything smaller than a 15" in IB/Open air. There's just nowhere near enough output to even bother with it.

[ubernoob]

What about using an aperiodic membrabe? I did it in my first mini with a Dyn MW-180, it sounded nice but the material I was told was the best stuff to use was impossible to keep intact and I feared for my lungs so I ditched it.

If you experiment with different layers of felt material you could get a great result, you lose at lest 3db efficiency from memory and the phase ends up out by close to 180deg if you get the resistance correct.

[Tiger]

scraverX, on 16 March 2011 - 01:13 PM, said:

Another option would be a small enclosure built under the shelf.

x 2

[scraverX]

Just an example, the Polk MM1040 can have as little as 0.65 cuft of enclosure volume (which aint a whole lot) Though I do have to say I haven't heard/seen how they go. I'm running a pair in a fairly decent size enclosure and I've got a fairy hefty (6-9db) peak at 50Hz which aint great for linearity and required some squishing with the EQ.

[Riley.]

i was very happy with my IDQ 12 when i had it running IB in the parcel shelf of my Aristo

the only limitation i found it had was the "cover" that goes over the shelf vibrating like a bitch

[scraverX]

Some good info and basic diagrams on Infinite Baffle/Free air can be found at the link below.

http://www.the12volt...udio/boxes1.asp

I personally like the bottom two options. Theoretically the existing 10" mount point becomes the vent/or one of and then you could fit a 12" in with no trouble at all.
Just my $0.05 from having a quick look with not much knowledge.

[Poohbear]

Thanks for the advice guys, the 12volt site gave me a few extra ideas.
I will initially try IB with a Seas Lotus 250 powered by a 500watt mono amp. Lots of stiffening to the parcel shelf, tune listen, tune listen.

Then if not happy... back to the drawing board and build a small box around the speaker in the parcel shelf.
May want to exchange the unit for a 300 if the sound doesn't measure up (the joys of endless tinkering!).

I want to hear the double basses and the timpani in the orchestra without shaking the next suburb!
Seems like a fair bit of the budget might go on deadening and sealing the boot to help the sound.

Taking my time and doing it all carefully with lots of auditioning, seems to be the way to go.

Shame the speaker manufacturers don't promote more of their subs IB for those of us who want to try this.

[muzzy66]

Sorry if this response is a little late, i admit to being too last to read the last few reesponses...

That said a Focal sub might be worth considering. I've noticed the KX series subs seem to have a very high Q (around 0.7) which might allow them to work nicely in a well designed IB arrangment.

I'd be concerned about frequency response myself - even good midbass drivers can get a tad stong under 40hz once you add cabin gain in an IB arrangement (probably up by 2 dB or so at 35hz) so I'd imagine that running a large displacement driver like a 10"+ subwoofer could lead to quite a boomy bottom end. It might take some significant EQ work potentially to smooth that out.

Just a consideration