Danny Richie "fixes" the Linkwitz Arion loudspeaker

Not "just" flatter frequency response (so that’s now a bad thing? ;-), but also improved spectral decay (aka waterfall plot) response, phase coherency between drivers, lower baffle panel and enclosure resonance (Linkwitz specified un-braced .75" MDF, Richie braced 1.5" MDF) , and a few other loudspeaker performance characteristics. Plus air core inductors in place of iron core, film capacitors in place of electrolytic, and good resistors in place of sand cast. For those who consider such matters important. I personally wouldn’t even consider a loudspeaker that digitizes the signal in its x/o.

I’ve learned that a lot of Audiogoner’s aren’t much interested in DIY, but Linkwitz owners have already built the OB frames for their loudspeakers. Still, assembling crossovers is a more demanding task that glueing and painting an MDF flat pack.

There are a few guys building GR Research speaker kits for guys who either can’t or don’t want to do it. Maybe somebody on the DIY site is offering the same for Linkwitz customers.

One of the reasons I gravitate towards planars is that they provide a sound that is more "seamless", 20Hz to 20kHz not being broken up into as many segments, with the then requisite (often) complex crossover. Full range ESL’s and magnetic-planars reproduce instrumental and vocal timbres in a manner I’ve never heard from a dynamic speaker. I learned that lesson when I sold my Magneplanar Tympani I’s to get a pair of Fulton J’s. Yes, the latter’s RTR ESL tweeters provided greater transparency that did the original Maggie tweeter, and deeper bass from it’s transmissionline-loaded woofer, but at the cost of everything being "cut from the same cloth".

My Eminent Technology LFT-8b reproduce 180Hz to 10kHz from a pair of identical m-p drivers! An 8" woofer in a sealed enclosure for 180Hz down, a ribbon tweeter for 10k up, both with simple 1st-order filters. My ET LFT-4’s do all frequencies from it’s pair of segmented full range m-p drivers. If I was loaded I’d get myself a pair of big SoundLab ESL’s. For around $15k, one can get the Sanders ESL, which I have heard and love. Roger's Music Reference ESL's were on my "to hear" list, but I never managed to do that. @clio09, do you have a pair?

Orion and LX521.4 owners are sophisticated enough to have knowledge of all the following, but for others:

There are a few well known benefits to be had by using an outboard active line-level crossover in place of a passive speaker-level one. A main one is keeping the bass frequencies out of the amp that is driving the midrange and tweeter drivers. That is why bi-amping without inserting a line-level x/o before the two power amps doesn’t provide the same degree of improvement as does sending a filtered signal to each amp. Keeping the bass frequencies out of the amp reproducing the mids and highs allows the m/t amp to produce less distortion, and leaves much more available power for the midrange and tweeter drivers.

My Magneplanar Tympani T-IVa loudspeakers came with a pair of outboard passive speaker-level crossover boxes, each box placed inline between one channel of a single stereo (or dual mono) power amp(s) and it’s designated speaker. So even though the bass, midrange, and tweeter drivers are seeing filtered signals, the power amps are not. A single stereo amp driving all three drivers---woofers, midrange, and tweeter---reproduces all frequencies.

The Tympani crossover creates a 3rd-order (18dB/octave) high-pass filtered signal at 250Hz for the midrange/tweeter panel (the mid-tweeter x/o is located at 3kHz, the two drivers not worth separating), and a 2nd-order (12dB/octave) low-pass at 400Hz for the woofer panel. Those are referred to as textbook crossover filters: they create their assigned slopes only. To actively bi-amp a Tympani, the stock speaker-level crossover is simply replaced by a line-level x/o that can provide the same textbook filtering. Doing that allows the Tympani to achieve a higher level of sound quality, and Magnepan recommends it in the speaker owners manual. I purchased a First Watt B4 to use with my pair of Tympani T-IVa, the B4 being perfect for the job. Excellent design and build, and reasonably price ($1500 retail).

Linkwitz obviously believed in loudspeakers having an active line-level crossover. But his loudspeakers incorporate crossover filters far different from textbook filters. The filters he designed for the two above models do more than just create simple high-pass and low-pass slopes; they also include parts that provide tailoring of the response of the drivers within their respective bandpasses. Line-level textbook filters cannot provide that tailoring, and Linkwitz resorted to using digital processing to do his filtering on the two models being discussed.

His friend and neighbor Nelson Pass (designer/maker of the First Watt B4, of course)---knowing that digital filtering was not going to be well received in Asia---asked Linkwitz if he wanted him to create an analog x/o for the LX541. Like the Asian’s, I do not want all my source material to go through digital processing.

Danny Richie is also against digital filtering, and that is one reason he eliminated the Orion’s complex stock digital x/o and created his own speaker-level one. The filtering required by the individual drivers could not be done at line-level in the analog domain, so Danny created speaker-level filters that not only replicated the stock digital filters, but also "corrected" what he considered to be imperfections in the speaker’s performance. Whether one prefers the stock performance of the Orion, or Danny Richie’s Modified one, is a matter of personal opinion.

I long ago realized planars are my preferred loudspeaker design, but at least the Linkwitz are open baffle dipoles ;-) . I much prefer large sheets of mylar over dynamic cones for my loudspeaker drivers. Danny uses cones, domes, and magnetic-planar drivers in his loudspeakers, and imo is a master designer. Don't let his good ol' boy demeanor fool you: he is very sophisticated and knowledgeable.

Great @clio09. The Madisound OB frames are real nice, made of Baltic Birch. Does Madisound sell the LX521 OB/Dipole woofer frame alone? I installed my OB/Dipole woofers in the same style frame (Danny refers to it as a "W", others an "M", and Madisound a "V". All the same thing ;-), not the more common H-frame.

One thing to consider is adding a second layer of BB or MDF to each side panel, to stiffen them up and lessen their resonance. And a sidewall-to-sidewall brace can be installed on the "open" (typically front) side of the frame, again to add cabinet stiffness and therefore reduced resonance. Another tweak is installing a layer of ASC WallDamp between doubled-up side walls, again to reduce resonance.

Brian Ding installs a 6dB/octave "shelving" circuit into his Rythmik A370 plate amp when used in an OB sub, to counteract the dipole cancellation inherent in OB woofers. That’s an easy filter to construct, just a couple of parts.

@clio09, interesting that both Roger and Bruce Thigpen ended up going with an 8" woofer in a small sealed enclosure to mate with their respective planars, Roger’s ESL’s, Bruce’s magnetic-planars. I deeply regret having been unable to hear Roger’s ESL driven by his direct-drive OTL amp. Now THAT’S the way to make a loudspeaker!

Danny Richie uses a pair of OB/Dipole subs up front (each sub having a pair of 12" woofers), and a pair of 12" sealed subs in the rear, with the rears in polarity opposite that of the fronts.

Good to hear @clio09. May I ask what that way is? One way to make bass more uniform throughout the room is by way of the DBA: Distributed Bass Array. But regardless, in rooms having dimensions shorter than the longest wavelength being produced, there are going to be standing waves, areas of high and low pressure. It is the room "ringing."

True, bass traps are very inefficient, but I got lucky and found a bunch of ASC Tube Traps for ten bucks apiece, including a pair of 16"!

Siegfried Linkwitz certainly appeared to me to be a genius. However, he designed the Orion with a required digital active crossover, and needing 8 channels of amplification. Not a loudspeaker I would want to own.

SL had his design priorities, as did/do Paul Klipsch, Peter Walker, Arnie Nudell, Richard Vandersteen, Jim Winey, Bruce Thigpen, Roger Sanders, Dave Wilson, Eric Alexander, and (shudder) Amar Bose.

Danny Richie has his, and his customers and clients (including companies making loudspeakers designed by him) seem to be amongst the most satisfied I know of (yes, myself included). To each his own!

I have learned that even the best hi-fi designers may have a blind spot. I think very highly of Roger Modjeski (Music Reference, RAM Tubes), yet discovered his in a blog he posted on his MR AudioCircle Forum. He questioned the rationale for bass traps, saying we pay more for loudspeakers that reproduce the lowest frequencies, then install bass traps to absorb the low frequencies those loudspeakers are reproducing? That statement/question revealed to me that as good an electronic engineer/amplifier designer as he was, he was not aware of room modes.