While awdio is just being argumentative, I did enjoy re-reading this nearly 7.5 year-old thread. I still have the same amp, speakers, and subwoofer, but the DAC-preamp is now the Benchmark DAC3 (after a misstep with an Oppo),but I've moved and I'm in a completely different room which is much more advantageous for an audio system. The set-up and adjustment of the system is also quite different.
In the house I was living in when I posted the thread I used a room that was very problematic for smooth frequency response at the listening seat. When I was shopping for speakers in 2009, I listened to so many alternatives. I was using a pair of Legacy Audio Focus at the time, and they sounded good, but by 2009 they were not good enough compared to the competition. (The Focus was also not voiced for accuracy, and had a classic saddle-shaped frequency response. Accuracy became paramount to me by then.) Then I heard the Salon2s at a dealer with what must have been a nearly optimal set-up, and I fell absolutely in love. I spent hours listening to many kinds of music on them, I was enthralled, and ended up buying a pair.
Unfortunately my room at the time was nowhere near as good as the dealer's, especially below about 100Hz, and I spent the next two years fiddling around with placement to no avail. My room just sucked. Later in 2009 I decided to take matters into my own hands, and I came up with a staggering brain fart of an idea to use a pair of passive subs with equalization I would tune myself. In preparation I swapped out the amps I had been using and ordered an ATI AT3004 to power the subs and the Salon2s. The AT3004 was turned into a 3005 for no extra charge by ATI when I ordered the amp, because they ran out of AT3004 back panels. How could I say no?
The subs I was considering were a custom-made pair using the Linkwitz Thor design, and I was looking into various crossover / EQ electronics options, but my high intensity job postponed action. A speaker builder friend of mine back then convinced me my concept was overly complex and expensive. He made the case that I should instead get a pair of the latest powered subs with built-in PEQs, and then I'd have many tuning options. He also recommended getting one sub at a time, because one might be enough, depending on the room. He was very impressed with the new 2010 Velodynes, and I was impressed in the local dealer demo, so I ordered a then brand-new DD18 Plus. I wasn't in the mood to fiddle with ID vendors back then either, and the sub market wasn't as advanced as it is today. I also ordered a Parts Express OmniMic, and a lot of my free time was spent fiddling with the system.
The DD18 Plus was very impressive in my room in test tones, but the combination of Salon2 placement, sub placement, crossover frequency, and PEQs was pretty overwhelming. I finally got the Salon2s to sound okay by running them full-range driven by one ATI channel each, and I used the Velodyne and it PEQs with a 100Hz low-pass filter to just fill-in the suck-outs in the Salon2s in-room response at my listening seat. Yes, three ATI amp channels sat idle. "Okay" in this case meant very good by most people's standards, but the Salon2s still didn't absolutely blow me away like they did at the dealer. My room really did suck, and apparently no amount of tuning was going to fix that. Since I wasn't completely thrilled I wasn't ordering another DD18 Plus either, because I figured the Salon2s weren't a permanent solution.
The point of this thread, the clipping of the ATI amp on a rock CD, did indeed turn out to be a Velodyne design flaw that applied only to the XLR inputs. The single-ended inputs had gain controls on them, but the XLR inputs didn't and the low gain of the ATI amp was requiring output settings on the Benchmark pre-amp that overloaded the XLR inputs on the Velodyne amp. Velodyne had clearly assumed higher-gain mains amplifiers for the DD Plus designs. When I noticed this I was experimenting with using a high-pass filter for the Salon2s which was built into the subwoofer, so the distortion from the sub was passed on to the ATI channels, which use a comparator circuit to recognize clipping. Hence the clipping light.
The clipping problem was solved two ways. First, as I mentioned, I decided to run the Salon2s full range, which eliminated the circuitous signal path through the sub. Second, since the sub inputs would still overload, I inserted 10db XLR attenuators into the subwoofer input cables, which allowed the ATI to get the volts it needed, and allowed the Velodyne to operate in a very comfortable gain range. Velodyne blew me off when I discussed the flaw with them, even though their support guy agreed with me that it was a design flaw. Whatever. The DD18 Plus operates flawlessly otherwise to this day, and Velodyne appears to be far less serious about the subwoofer business anyway, as owner David Hall focuses on Velodyne LIDAR. In other words, this is almost certainly my last Velodyne product.
The ultimate solution was really a different house with a better audio room, which happened in 2015. Essentially the same set-up, now tuned much differently, with the Salon2s running full range and a single DD18 Plus fed with a full-range signal using a 100Hz low-pass filter and five PEQs (of the eight total) adjusted for fill-in of the Salon2 in-room response. Numerous hours of measurement, tuning, and placement experimentation resulted in very smooth and tight bass down to 20Hz at my listening seat. The resulting sound at least as good as I remember at the dealer's years ago (using many of the same recordings). Imaging and mid-high smoothness and realism were now exemplary. I flirted with a few alternative speakers, mostly electrostatics and the KEF Blades, but nothing seemed anywhere near worth the huge expense, so I've stuck with the Salon2s. The DD18 Plus has been out-classed by several more recent subs, but the truth is that with the Salon2s running full-range I have the equivalent of three subs, and the Velodyne doing fill-in only isn't breathing very hard, even when I'm getting ambitious with the volume levels. The system is music only, so HT/action movie requirements don't apply.
I will confess that I do currently passively bi-amp the Salon2s. With the Legacy Focus passive bi-amping did make an audible difference, IMO, because of its idiosyncratic design. The Salon2s are an easy load by comparison, so for two years I was running the Salon2s single-amped. But a while back, in a thread on bi-amping, Alex2507 dared me to try bi-amping again with the Revels, and on a boring weekend day I did, since I had all of the cables just sitting in a box in a closet, and I had two spare amp channels just idling. There was no audible difference I could discern at all with any material, including a well-made recording of Respighi's The Pines of Rome. Because the cabling changes are actually a pain in the butt, or the knees in my case, I left the bi-amp configuration in place for a time, since it was doing no harm. While I still had the Salon2s bi-amped, a friend came over, an electrical engineer I worked with, and he gave me a precious lecture on how stupid passive bi-amping was. I so enjoyed the lecture I left the configuration bi-amped, and I later enjoyed two other lectures, one from a high-energy physicist, so I made the passive bi-amping permanent, and even purchased fancy Blue Jeans speaker cables to make it all pretty. I haven't had one of these lectures recently, so I'll have to invite a physicist or two over to tell me how stupid I'm being. (Yes, my behavior is probably indicative of some personality flaw, but psychotherapy costs money and takes time, so the hell with it.)
