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Author Topic: Sub Woofer Cracking Noise Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 11-28-2010 12:20 PM                     Sorry Steve, didn't get that, I thought you were talking about yourself or someone else!  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 11-28-2010 01:06 PM                     I knew you were going to say my room is only XX by XX however my thoughts about using two or more subs are always in terms of achieving the lowest possible THD from that channel. Very few if any every day theaters have LF harmonics of less than about 10% and are usually much higher. A single 4645B when driven by the proper 656 watt amp as Steve says will be needed will net you incredibly high amounts of harmonic distortion. It is also a prooven fact that the bigger the woofer the higher the harmonic distortion it will produce. The laws of physics come into play on this and there is no way around that except to go with multiples... but if you like distortion than this is all great! It takes lots and lots of power and multiple speakers to create clean realistic low frequencies. I'd go so far as to say say the 656 watt amp wouldn't even be enough for a single 4645B woofer for it too would also be straining. More liike a kilowatt of power might be adaquate as then at least you have an ounce of head room!! Multiples are always better then singles to both lower the distortion to reasonable levels and to keep the power levels and operational excursion of the woofers with in reasonable limits. Unfairly, all this in the end is dictated by budget constraints and price cutting on jobs and installs . RE: The 4645 box... What a piece of crap! I too had to repair several of them very recently... they literally fall apart while in operation. It's amazing that very many of them make it to a job site intact... Don... Just send the woofer to Steve... Mark  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 11-28-2010 01:17 PM                     speaking of rooms: small listening rooms are more prone to room modes. My listening room had a huge dip of -25dB in the middle of the room at 40Hz. Dreadful. Being a small room, it is likely to have some room modes to some degree. This may affect your low frequencies and you may need more power to compensate them. Usually the 2242 do not break, after reconing it please try to assess why it broke or you may find another hole in the cone very soon!  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-28-2010 03:51 PM                     Both lower distortion and distortion from power-compression are reasons to go with multiples. That said...I think you would be amazed at how little distortion from that driver would be reduced. The 800-watt rating of it is for continuos pink noise over several hours. It has an incredible amount of power handling and cooling built into its design. It is one of the most impressive drivers I've ever dealt with. The only knock some may have with it is that it does not go as low as some drivers. Most drivers that go lower have foam or, better yet, rubber surrounds (compliance). However, with those you typically also loose out on power handling as the suspension becomes much more sloppy. -Steve  |  IP: Logged

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