Octy Mk1 Front speaker replacement

Hi,

I repalced the HU in my Mk1 Octy as soon as I got it for a Sony CDX-R3300 (50W X 4 apparently) and all has been fine for the last year or so. But I've finally blown the front right speaker. I still get some treble out but no bass what so ever.

I've read on here that the depth of the replacement speaker is critical so I was after some suggestions for a direct replacement. As this has happened I want an upgarde in sound quality (but that's not hard from the factory fit one's) but don't really need the top of the line speakers.

I listen to all sorts of music but most of it is guitar based but I do indulge in the odd bit of dance so I'm after a good all rounder.

Cheers for any help,

Andy