Hi JLM,
Yes, the datasheet does make it seem like these are 121 dB/w/m at 8 ohms. My guess is that this is for the compression driver and that the mid-bass is significantly less efficient. At the bottom of the datasheet is a frequency plot (using the GPA crossover) that suggests in-cabinet efficiency ~99 dB/w/m at 8 ohms from 50Hz upwards; a ‘better’ cabinet and room-gain will extend bass evenly below that. Great Plains Audio seems to provide realistic specifications, so I am inclined to trust the plot.
They are beasts of drivers and very well suited to being driven by SET amps – this was one of my criteria for selecting them. That said, I would probably not have chosen them if not for the Rick Craig crossovers being available and knowing I could have a decent cabinet designed them.
After I have had some time with them I will share my impressions etc. in a thread here. I’d also like to present the project in some way, without giving away Scott’s or Rick’s designs – something that could help people decide whether such a system would be appropriate for them, what types of issues need to be considered and point them in the direction of knowledgeable people that can help them along the way. I have some ideas for a simple web site, but my time is limited.
Cheers,
Raymond.
