I was going to do this in a PM to you Danny, but I figured someone else may find the info usefull, so here goes.....
I am preparing to put together a pair of OB H-Frame subs using the GR 12" drivers and Rythmik plate amps, and your answers to these questions will help me do so in a more informed manner. Here's what I would like your thoughts on:
- I saw how DonS put together a pair of H-Frames under his Geddes speakers, using the subs as stands for the speakers. The H-frames were sitting upright, the two drivers in each in vertical alignment. This made me wonder.....since H-Frames are dipoles, with nulls to either side, they can be placed close to side walls without penalty. Can H-Frames be placed laying down, one side on the floor, the two drivers aligned horizontally, also without penalty? I ask because it occurred to me that a pair of H-Frames could be used as stands for a pair of old Quads. Ignoring the matter of sub placement in regard to room modes, what are your thoughts on this idea?
- The GR 12" OB drivers have an impedence of about 12 ohms, and therefore provide an optimum load to the Rythmik amp when used as a trio, as the amp is designed to have maximum power output when looking into a four ohm load, the combined impedence of three GR drivers. This alone increases the output of the amp. Using three drivers also increases the output of the sub simply because of the fact that three drivers move more air than do two. Is this all true, and therefore three drivers per amp is preferable to two? Is there a penalty to be paid for using three drivers per amp? Is 370 watts for the three drivers enough, or would you recommend the 600 watt Rythmik amp?
- In building the H-frames, does the distance of the box walls from the driver make a great deal of difference? For instance, two inches vs. four? How about the depth of the boxes?
- For flush mounting of the drivers, what should the diameter of the hole for the basket be? The depth? And the through hole?
Okay, that does it for now. Thanks---Eric.