Speaker Asylum: REVIEW: BD Design Oris 150 w/ PM4AER driver Speakers by Kurt Strain

Model:	Oris 150 w/ PM4AER driver
Category:	Speakers
Suggested Retail Price:	$4500 as equipped with painting and my own labor
Description:	Two-way biamped front-loaded Lowther horn system plus Onken bass bins
Manufacturer URL:	BD Design
Manufacturer URL:	BD Design

Review by Kurt Strain ( A ) on June 25, 2002 at 09:35:42
IP Address: 192.25.142.23

Add Your Review
for the Oris 150 w/ PM4AER driver

After all the breaking in and all the minor tweaks to this product and all the DIY 71A SET amp adjustments for the horn part, this is so far and away better than anything else I have heard that I actually think I'm basically done with speaker/amp combos for my house. Nothing has been changed in this area of my system in months now, and there's no itching to try for more.
Get the best driver you can afford and the best low powered SET you can make or purchase. The best amps are probably not commercially available for this 108 dB sensitivity I believe, but at least try to get a really good 45 SET to go with it. The speaker reveals how much better a 71A is, however, IMO of course. The best HF horn amp for it will be optimized in the 1mW-100mW output power range. Amps more than 500mW per channel are overkill in terms of power, and it will satisfy most anyone's need with 200mW per channel. My 71A puts out about 400mW before clipping.
Another trick I employed is a 2 dB passive equalization bump below 800 Hz, accomplished in the DIY 71A amp. Actually, the amp shelves off 2 dB from 800 Hz on up. This equalizes this system even better than just front loading alone, but just one pole/zero filter is all you want. You don't want to overequalize as this reduces transparency. Does this mean it sounds colored? Compared to other speakers, it's color free with the most natural timbre. Remove the distortion and the dynamic slop and frequency response variations play a much more unimportant role in timbre from my observations. The key thing is clean linear repeatability across the frequency and amplitude axes I'm betting that provides exceptional timbre. And this speaker has the best timbre I ever heard, when mated with the right SET amp.
One highly disturbing and unrecommended tweak I did was to add a thin coat of damar varnish around the outside 1" edge of the whizzer cone. It may some day come back to haunt me, but the result with the small equalization was a complete removal of all residual Lowther "shout", even somewhat there with this AER version. I personally am very sensitive to this bit of shout that happens only on some loud solo instruments that hit this area just right. So I took these measures. Most will not notice nor need to do this. I didn't notice any significant loss of detail, which is in spades, but it does run a tad smoother.
Another tweak I did to improve the speaker include: lining the interior walls of the Onken cabinets with 1/2" thick "Wonderboard" cement board, applied with Liquid Nails and sheetrock screws, which really adds dead mass and stiffness to the MDF cabinets and cleans up cabinet vibrations without losing the rhythmic drive of the music (actually it improves rhythmic drive by diminishing what gets lost in the MDF and keeps the walls more stiff so more driver air goes out the port and not into the cabinet vibrations). I use a simple inexpensive 100W subwoofer amp attached to the backs of these speakers that covers 20 Hz - 160 Hz with a second order rolloff above 160 Hz (adjustable crossover frequency and volume. I drive these amps from a DIY 6H30 cathode follower that buffers it from the transformer volume control and drives long interconnects. It matches to the Oris horns nicely, but I am certain this is not the last word in bass, but a good compromise for floor space.
The rest of the stereo system is not really all that crucial to get good sound, because after all it's a forgiving low distortion horn. But it will take the finest front end equipment and rear end amps and give you your money's worth from good choices.
I had a pair of great sounding $17K horns before hearing DrM's Oris 150's and I was blown away by the improvement the Oris offered in terms of higher microdynamics, higher transparency, and even less distortion, up to 105 dB at 1m peak sound levels, and was just plain goosebumping me. Above that loud level and the more expensive horns won. Oris 150's are best run at anything from low to loud listening levels, but not into the neighbor-complaining extra loud levels. Front loaded Lowther drivers are not about extreme volume, but it will play extremely loud. They are about low distortion and great articulation with stop-on-a-dime / black-out quickness with reasonable imaging. They are closest to sounding like live in the most realistic sense. Not holographic, but the soundstage is excellent IMO.
The emotional impact is the strongest I've encountered from any speaker system. How does it communicate the artist's intent? By giving you everything important about what he's doing. Some music I previously thought was lackluster playing actually came alive with subtleties of technique, style, and even drama I never knew before.
If you're looking to dissect the directional cues of a performance, this is not your ultimate speaker, yet this tweaked Oris 150 is quite possibly the reference speaker in the world today, in terms of delivering an artist's musical message, delivering in state-of-the-art details that are more important to the music.
This speaker will show why 108 dB sensitivity (a true pink noise 108 dB, some would call it 110 dB) will outperform 98 dB sensitivity as much as 98 dB sensitivity will outperform 88 dB sensitivity. The super high sensitivity speakers are just more linear and uncompressed and amplification becomes almost a trivial job to do correctly, approaching near zero effort. These drivers are a nominal 12 ohms, without a crossover from the 71A amp's point of view, simplest and easiest speaker to drive, especially since it is only 150 Hz on up. The Onken cabinet is the achille's heal, but other solutions are out there for the bass bins, if you got the space. It's the same problem all speakers have to try to solve, and at least in this case the Oris 150 is left alone from that messy area. But this stiffened Onken cabinet is amazingly clean and does have enough speed to not sound slow and sluggish overall. It isn't detracting much from the music, from my point of view (use heavy spikes under them, for sure).
In summary, this speaker is the best I've heard to deliver what seems naturally important to high fidelity - the art and science of delivering the music's intent, and not bad at all at doing the lesser important aspects such as laser-beam image focus. Good enough where I expect to wear out the drivers if I live long enough. Of course, my last "lifetime" speaker purchase lasted 1.5 years. I've had these speakers over 2 years, and there's no sign of a better one coming. Maybe a more improved driver to go into this horn, if it happens. And maybe a better bass bin, but this is the SOTA compromise of size and performance for me in 2002.

Product Weakness: Minor nitpicks: Imaging not SOTA, bass bins looking for a better solution, if it can at this size. Your horn amp has to be low hum and noise.
Product Strengths: Astonishingly realistic portrayal of a musical artist's intent. Plays anything well. Low distortion over wide dynamic range and lightning quickness with awesome timbre. The stuff that's important for true high fidelity, IMO of course. Amp choices for the horn is wide open, from 100mW to 100W, but anything over 1W is not buying you anything.

Associated Equipment for this Review:
Amplifier:	DIY parafeed 71A with 01A driver and Magnequest cobalt EXO-45 OPTs.
Preamplifier (or None if Integrated):	DIY Transformer Volume Control, range = -45 dB to +10 dB voltage gain
Sources (CDP/Turntable):	Teres TT with lead shot/acrylic platter, JMW-10 arm, Koetsu Urushi / Sony SCD-777ES SACD player
Speakers:	BD Design Oris 150 / Onken bass bins
Cables/Interconnects:	DIY thin gauge wires
Music Used (Genre/Selections):	Classical, Jazz, Classic Rock
Room Size (LxWxH):	22' x 30' x vaulted
Room Comments/Treatments:	Carpet, tapestry wall hangings with 4" insulation behind them..
Time Period/Length of Audition:	2 years
Other (Power Conditioner etc.):	Balanced power system
Type of Audition/Review:	Product Owner

Product Weakness:	Minor nitpicks: Imaging not SOTA, bass bins looking for a better solution, if it can at this size. Your horn amp has to be low hum and noise.
Product Strengths:	Astonishingly realistic portrayal of a musical artist's intent. Plays anything well. Low distortion over wide dynamic range and lightning quickness with awesome timbre. The stuff that's important for true high fidelity, IMO of course. Amp choices for the horn is wide open, from 100mW to 100W, but anything over 1W is not buying you anything.