Originally Posted by jmcomp124
I am enjoying this thread and the wealth of information in your web-site. Thanks to Larry!
Your approach uniquely shines as it goes for the most accurate reproduction digging deep to the single digits and the spectrographs that show comparison to the reference standards is worth a thousand words. I want to start doing this sometime soon. With your raptor setup, while the in-room frequency response at the primary listening position is almost flat down to 3Hz, how about Max SPL in the lower octaves? Do you have Max SPL sweeps (covering down to 3Hz) that you can share? Also it will be very interesting to see power compression at these low frequencies. I currently have a passive radiator design and have always thought about single digit frequencies that my current design is not capable of.
I have this one, but I cut it off @ 5 Hz.
I have another one where I pushed them a bit further, but I can't find it right quick (these bloody Mary's might have something to do with that).
This was not my new Raptor System, which includes my newly redesigned amp and BHT-15 drivers. I'm not ready to show that one yet.
Still, it indicates that reference level to < 5 Hz without compression is a certainty in my room.
Sine sweeps below 10 Hz are not a good indication of what a system can do with WOTW, et al. REW generates a linear sweep from DC-10 Hz, then a log sweep from 10 Hz and up. Even then, the havoc wrought on the system and the structure is exponential to > 10 Hz sweeps. I actually hate doing it because it's a brutal assault on room and person and, other than the similarity to outdoor GP compression sweeps, it really doesn't say much more than what the system can do in-room while playing sine sweeps.
I wish Larry could have showed up just a few weeks later because when he was here I didn't have the new amps yet and the system as he heard it wasn't finally tweaked. Just yesterday I mentioned to my son that recent movie watching has me floored at how well the subwoofer system is performing... like nothing I've heard to date. He told me it's just been a long span of time where I never stopped looking for a weak spot to redesign and the improvements, although many were just slightly incremental, have summed to what I'm listening to today.
I'm actually quite proud of what years of chipping away at accuracy in-room to whatever bandwidth the disc asks for has resulted in. Very soon my analog PEQ will be ready for testing and that will put the icing on the cake of what I believe is the cleanest, most compact, most versatile and widest bandwidth system on the planet without having 40 or more cubes of boxes and multiple amplifiers in the room.
I wanted to take this opportunity to mention my eldest son who is the electronics genius of the house and has built the analog SEQSS and PEQ, tweaking them to perfection over 2 years time. They're dead quiet, flat to DC with no DC offset, do not clip under the most demanding scenarios to reference level, have the best components (after auditioning and measuring many versions), are factory adjustable, are deadly accurate and have a power on LED that changes colors to let you know when the real deal is being fed into them. Most importantly, they're specifically made for insertion between soundtrack source and the new amplifiers.
Without that card to play, I never would have been able to get what I designed on paper. It's just not commercially available and it would have taken the rest of my life if I had to do it myself. I would've had to buy some digital POS and live with it.
Here's to everyone... have a great NYE.
Actually, Larry... well, this is his thread so I'll just say you might want to keep an eye on this thread over the next couple of months.