I've been given a little more leave (not much mind you!) to play with my Impreza now, so I was thinking of a pair of 8" subs in the back shelf.

I know that 10 or 12" would be better, but the constraint is that I need to maintain luggage space, and keep the weight down as much as possible.

Does anyone know of any 8" subs that will work in free air (I think that's the term... and that are reasonably priced?

Also about filtering - I can make a simple passive network easily enough, but would there be a huge difference if I put a low pass (or band pass) filter on the amp input, rather than a passive one on the output? - benefits such as more usable power from the amp maybe??

Oh and yes, the fronts will be upgraded by the time I do this... Nice Infinity components if I get my way :D If not, there are some Kenwood components that are a bit cheaper, but look good at least on paper :)

TIA

Free air, or infinite baffle, is the type of sub you're looking for. You just need to isolate the air at the front of the speaker from the air at the back.

I'd recommend using active filtering on a sub, otherwise you're losing a lot of power through passive filtration.

I'm assuming you've upgraded the head unit. On most recent kenwood units you'll find there's probably a built in crossover for the sub output... Have a look at that option and you might find you don't need anything else.

Yep, decent fronts and a sub are IMHO about all you need. Although saying that I do have rears in, but they're very very faded out, and are just running off the head unit's internal amp.

I heard a system in a subaru the other day and it was very nice. It was only 2 Kicker 8L7s and they were mad. At the moment, bass junkies are doing a deal buy one and get the other free. They are £199 for the 2. Excellent subs and had me shocked.

I think the guy made a little enclosure in the side of his boot

Thanks for that. I'm plotting and planning now :)

"Although saying that I do have rears in, but they're very very faded out, and are just running off the head unit's internal amp."

Chiark - have you tried any sort of filtering?
It was known as a 'Hafler circuit' - probably the fore-runner of Dolby Surround and I still use it on the rears:
Mono, Left minus right, 2K-7K only and attenuated by 12dB. Get it right and it's awesome! What you should here is a static-sort of noise, but this in essence is ambience. Try it!

Thanks :)

Yes, it's a Kenwood head unit with the MP3 changer :D
It works quite well. I'm not sure that the HU is new enough to have the sub filtering options (it's a couple of years older than the changer, and still has a tape player :eek:)

You've confirmed more or less what I was thinking about the filtering. I'll have to sort out a couple of opamps if the HU has no filtering itself.

Looks like this one may work out (for once) Decent fronts and subs ought to make a reasonable quality system, didn't they?



[Edited by dnb - 1/10/2003 12:39:22 PM]