1 Pair Reference Standard Monitors 1.0

and 1 Pair Reference Woofers Monitor 1.0

List Price: $12,550 for the complete system





Really? Really?

Publisher's note: Bruce Brown is the owner of Puget Sound Studios

and is a professional mastering engineer

who has worked on High Res masters for HDTracks, FIM and Dave Wilson's Master Tracks to name a few.


Sometimes, something comes along and you just can’t figure it out. It defies all logic and makes you readjust your whole thought process.

When putting together an audio system, you have to think of it as a “system”. There is a synergy between each component and every little thing is cumulative. When every thing just gels together, it makes a great system. The whole is greater than the sum of its parts. Sound familiar?

There are a lot of great audio products out there we’ve never even heard of.  Just because it is not a major player, doesn’t mean it’s not worth investigating. If that were the case, I wouldn’t have all the great equipment I have now. Some things are worth seeking out. The words “game changer” and “break through” get thrown around too loosely and kind of dilutes the whole meaning.  I’m not going to throw those words out and just tell it like it is.

No one that I’ve ever spoken to has heard of shelby+kroll. I know I hadn’t. That doesn’t mean it’s just another small company trying to break into the big time. Some of these companies are legit and deserve a shot to prove themselves against the frontrunners. But if well–known brand names were the top criteria, we’d all be listening to Bose, right?

When I first spoke to designer Tim Kroll, he told me he wants to put out a product that can compete with a “Known Standard”. When I asked him what that meant, he said, “We mean well known, well reviewed statement loudspeakers that no one would point at and say “not a standard” (YG Acoustics Sonja, JMLab Grand Utopia, Magico Q7, Wilson Audio Alexandria XLF, etc.).

Wow… forget about going after speakers in your own price bracket or even twice the price. He wants to knock the crown off the king! $100,000 monsters. That’s a tall order. This guy either has a pair of brass ones (either balls or ears) or really believes in his product. Or he has just been drinking some funny Kool-Aid! We’ll see.

       Tim Kroll, like many other speaker designers, decided one day after listening to some speakers, in his case the Wilson Audio WAMM’s, that he could make something just as good if not better for less money. As he told us, “My eyes have always been bigger than my wallet”. That sounds familiar. So he started experimenting. “Pretty soon audio buddies were asking me to build them sane things that were of normal size and I started my custom loudspeaker cottage industry: High Performance Audio. I would find someone who was good at cabinetry and guide them through the construction (you know, those who can’t do, teach). Then I would find someone with expensive speakers and have them bring them over for a comparison. The first customer outside of my audio buddies owned Dahlquist DQ-10’s. Am I dating myself here? I took them in on trade. Soon I sold them when I took in B&W 801 series 2’s in trade. Then it was Watt/Puppies, Martin Logan’s and I never looked back. My perspective was always if they can do it for $20,000, then I could do it for $4,000.” We like that kind of thinking!

According to Tim, the design goals for his speakers are:


Produce a loudspeaker that has:


       As I said, the whole has to act as a system. There must be a synergy that makes everything just right. I welcome the shelby+kroll Reference Standard Monitor 1.0 and Reference Woofer Monitor 1.0 “system”. I’ve never been one to advocate mini monitors mated to woofers. There is just too much hassle setting them up and dialing in the sub-woofers, not only to augment the bottom end of the audio spectrum but also to fill in any room modes that you may have.


       The shelby+kroll Reference Standard Monitor 1.0 is approximately 12” x 7” x 12” deep and weigh about 19lbs. each. They can either be ordered with or without matching stands.


       Each speaker is made from a composite sandwich of ultrahigh end synthetically hardened bamboo, Finnish birch, rigid bracing, proprietary damping, resonance tuning and is rounded on critical surfaces to minimize diffraction. Housing a  4” Aluminum honeycombed sandwich flat piston mid-range driver and a 1” Ceramic damped silk dome tweeter, both modified to shelby+kroll’s discerning specs.


      About their driver technology they state, “Our primary driver is constructed in such a way that it is more rigid than any driver used in $100,000+ mega-speakers. It is many, many, many more times rigid than any other cone used by any other speaker manufacturer --- period. More rigid, less cone distortion, period. In our primary driver we use a completely flat diaphragm. No more absurdities in trying to align the voice coil --- at all. The entire diaphragm is aligned and in phase. There are no phase cancellations or distortions from being off axis. This flat diaphragm also yields drastically better off axis frequency response. This is true in both the vertical and horizontal planes. It has a wider dispersion over a wider frequency range than any electrostatic, ribbon or conventional voice coil driven driver (we will point out why this is so important later). Another advantage just as critical, the diaphragm does not break up the way any other cone does.  This diaphragm does not break up --- AT ALL. This is accomplished by using a metallic honeycomb sandwich. The honeycomb construction completely prevents cone (or in this case flat diaphragm) breakup. No nasty, spurious spikes. How much does this ultra-rigid, no-breakup cone weigh? Under 5 grams! It weighs less than most of the lightest, least reinforced paper cones. The diaphragm weighs no more than a soft dome midrange diaphragm! This driver sounds faster and cleaner and more natural than virtually everything else out there regardless of cost.”

       Crossovers are minimum phase distortion utilizing very high-end parts like European foil inductors, foil capacitors and UPOCC Copper + UPOCC Silver wiring. They claim that their crossover design saves money because the drivers don’t require all the adjustment and correction (and thus number of expensive parts) that megabuck drivers require. “Many 6 figure mega-speakers can break the 4 figure mark in the cost of their crossovers and still there is significant timbre and phase damage done to the signal before it reaches the drivers. How can these very expensive speakers sound so good if that much damage is being done? We’re glad you asked. The answer is even with all that damage being done, they are still damaging the sound a fraction compared to cheap crossover implementations.”

       Binding posts are made of Gold, Copper, Silver and Rhodium but there is one aspect I do not like do not like. The angles of the posts are at about 15 degrees from perpendicular and make it hard to attach any spades that also have a bend as well. I just wish manufacturers would put decent posts on the back of the speakers that don’t have any bends or proprietary fittings. What’s wrong with that?

       Well, when we asked Tim about that he replied, “The way they are configured has come from customer feedback. Our customers have overwhelmingly preferred the downward tilt. The posts themselves are high dollar Cardas posts. We use them not because of their price, but because in this loudspeaker system they sounded better than any other high quality post we have tried. Wire manufacturers do things differently from each other and we are currently perplexed on how to accommodate everyone without a published standard that would tell us and all wire manufacturers how to match things up.”

      But how exactly does he design high-value/high-performance speakers? Well, here’s a couple of examples. “Encapsulating the crossover in good epoxy (to control resonances) was expensive, very time consuming, it took a custom mold and a lot of ventilation in the shop. So I used modeling clay. More inert, more vibration absorbing, I can mold it in 2 minutes and no house clearing fumes. It’s a wrap. Then I read about a manufacturer who wanted a better woofer port than the cheap, thin, resonant plastic one found in even really expensive loudspeakers. So they CNC one out of aluminum. That is really cool until you find out how much that adds to the cost. So lets see. The port needs non resonant walls and needs to be cheap. Electrical conduit with a little damping. Same results, no insane materials or labor. It was always, “How do I get 95% of the performance for 5% of the cost?”

       I did not try the Reference Standard Monitor 1.0 by themselves. Why would I? Their frequency response is only good down to 100Hz. This is why I stress that this is a “system”, which must be paired with its companion Reference Woofer Monitor 1.0. Made of a composite sandwich of ultrahigh end synthetically hardened bamboo, Finnish birch, rigid bracing, proprietary damping, resonance tuning that is rounded on surfaces to match the appearance of the RSM 1.0’s. Mated with a 300watt Class-D amp modified to shelby+kroll strict standards, the Reference Woofer Monitor 1.0 sports a 10” reinforced flat piston down-firing driver. Controls and inputs on the back are numerous. With high and low level inputs, LFE and pass-thru; these subs are ready to fit into any décor and room acoustics. Controls for gain, phase and crossover frequency make this sub adaptable to any mini-monitor or full-range speaker that you may use.





       Here's one very important note. Before they sent the speakers, they asked me to measure the height from the floor to the distance perpendicular with my ear canal while seated in my mastering chair before they built the stands. All floorstanders whether NanoMonitor 1.1’s or, in the case of this review, the Reference Standard Monitor 1.0’s, are built to the exact height needed for optimum performance for each customer. Can you name another speaker company that does that? Pretty nice bragging point if that's your thing - "Yeah, Tim Kroll built this pair especially for me!"

       I set up the Reference Standard Monitor 1.0 ’s approximately 52” from my front wall and 30” from the side wall. Toe-in was just so I could barely see the inside of the speaker, making the apex of the triangle about 24” behind my head. The matching stands filled with 100 lbs. of sand (not included of course) were used throughout the review. Using an Earthworks M50 measurement mic and a M-Audio Fast-trak Pro into Room EQ Wizard, I set the pair of subs up to where I had a +/- 1.5dB from 20Hz – 500Hz room response. This made a seamless integration into the RSM 1.0’s. Yes, I did say all the way down to 20Hz. Note that is or plus minus 1.5 db, even though the published spec claims a low of 30 Hz - but that's at +/- ONE db!. The published specs of the $50,000 Wilson Alexia (more about them in a minute) is 20Hz +/- 3 db, for example. The top of the line Wilson Alexandria XLF is spec’d at 19.5 HZ to 33Hkz +/- 3 db. But they are $200,000 per pair and weigh 655 lbs each.
I'm just sayin'...





       So what did they sound like? Nothing that I had ever heard. The imaging and soundstage were some of the best I’ve heard in my room. At any price.

       Going from top to bottom, cymbals had an eerie palpability. You could follow the decay all the way to the darkness. Vibes could give you goose bumps. I can actually feel the body of a baritone in front of me. Female voices were natural and not strident. Even Rickie Lee Jones sounded great! Sometimes her voice just grates on me with some systems.

       I bring up Rickie Lee Jones because I had just heard her perform at Jazz Alley the previous night so the tone and timbre in her voice were fresh in my mind. I was using the Analogue Productions of the “It’s Like This” 45rpm as a reference. The first cut, “Show Biz Kids” was perfectly represented the way I had heard it 24 hours prior. It was uncanny! Playing at low or high volume, the tonal character of these speakers did not change. Bass transients were fast without any overshoot. Mids were crystal clear without any muddiness. With the subs dialed in correctly, in a properly treated room, the coherence was seamless from 20Hz – 20k.

           I was reading one of the email’s that shelby+kroll had sent and it stated: Very bass heavy music: Reggae, Dance, Hip Hop, Rap, etc. can be played on these speakers BUT this kind of music will push the speakers to their excursion limits at a much lower SPL than other types of music.


       I wanted to see what they were talking about. My room is just over 3000cu/ft. and it may be a little larger than that in which typical customer would place such speakers, so I know I was at the edge of their output. I had a Heavy Metal project come in for mastering and playing it back through these allowed me to feel comfortable enough where I knew their limits and potential. I cranked ‘em! These babies can boogie! I didn’t feel they were at their limit of excursion or about to give up the ghost. I wouldn’t recommend this abuse all the time, but I can say without hesitation, that bass heavy music is not a problem!



     In the middle of the review I took delivery of the new Wilson Alexia’s. Shelby+kroll boasts great things about their speakers and they had the temerity to ask me to compare them to my new $50,000 speakers. Heck, their website compares their speakers to $100,000+ models!



     Like Muhammad Ali and Deion Sanders, it ain’t trash talkin’ if you got the skills to back it up! Let me tell you folks, the shelby+krolls speakers got SKILLS! The system didn’t run with its tail between its legs; no, it stood there toe to toe with the best. Granted, the Alexia’s weren’t fully broken in, nor were they in their final position and spiked, but the shelby+kroll speakers didn’t get embarrassed. I could easily live with these speakers and that’s is not something I say often. I am very picky! I’m a professional audio engineer. Speakers are not just a hobby for me.

     They may not be quite as dynamic or play as loud as a full range tour de force, but played within their limitations which are minor, you can’t get any better… Period.




     We here at Stereomojo talk a lot about dynamic range. It’s one of the characteristics that difficult to achieve but is critical in defining what makes something highly “musical” versus something else that might not be. Real music has a lot of dynamic range! Here’s something very interesting designer Tim Kroll had to say about Dynamic range: “Dynamic Range is often misconstrued as how loud something gets. Dynamic Range is really the difference between the highest and lowest SPL signals denoted in dB. In general, audiophile loudspeakers are usually defined as the following: The highest dynamic range speakers available are very high efficiency horn systems. If someone values high SPL or high dynamic range above all other attributes, there is still nothing that can compete with them. For most audiophiles the tradeoffs are just too great so they sacrifice dynamic range for other audiophile attributes. The RSM 1.0 and RWM 1.0 cannot match the dynamic range of high efficiency horn systems. The “Known Standards” can’t either. Most audiophile loudspeakers have rather limited dynamic range. Due to complex, high part count crossovers, even loudspeakers that are “Known Standards” very seldom “come on song” or hit the range that they sound the best until just 15-20dB before their limit. Most sound muffled or lifeless until they are getting some significant current. The big behemoths usually start to sound good between 90-95dB with their upper limit being somewhere between 110-120dB. They are usually high or very high SPL loudspeakers but the dynamic range where they sound their optimum is at best 20dB. This can be frustrating when piece of music that is high dynamic range is played. The listener has to compromise and either choose to:



     The RSM 1.0 and RWM 1.0 are not high SPL loudspeakers. If we made them that way, they would lose a significant portion of their spectral energy balance, tonal purity and detail. They are average SPL loudspeakers. But they are high dynamic range speakers. They sound optimum from whisper quiet up to their upper limit. The extra 10dB of dynamic range they provide is the hardest to get right; the quieter range, where the subtlety of music lives The listener can trade quantity for quality on watts when sourcing amplification. Listening fatigue is greatly reduced. The less than perfect sonic attributes of the room are less intrusive at lower listening. The extra 10dB of dynamic range at the lower end of the scale does not provide the brief pyrotechnic excitement and adrenaline rush of demonstration tracks often played in audiophile showrooms, but it does provide a lot more long term listening satisfaction. The listener can fully enjoy the quieter and louder passages without having to frequently bounce out of their chair to readjust volume.”

Nominal Impedance is 6 ohms. Tim says it's an easy curve, no phase angles

      I think that was worth sharing, don’t you? But I haven’t even told you the best part. If you purchase these speakers factory direct, they offer a 30-day money back guarantee! If for any reason you do not like these speakers, they offer a guilt-free return guarantee. They tout on their website that NONE of their customers have ever used that option. I can see why. They’re addictive, like audio crack.



       Per Tim Kroll: “For sound quality purposes, we are no longer offering custom height matching stands. Instead we are offering the RSM 1.0 as a bookshelf speaker or as a custom height floorstander. We were going to pre-make the monitors and then make each pair of stands to the proper height as each pair was ordered. It then occurred to us that we couldn’t pre-make the monitors and add the right height stands later as the grains wouldn’t match since they came from different bamboo sheets. The greater structural integrity of the floor stander vs the monitors and stands yields about the same sonic gain as moving from a $2000 interconnect to a $3000 interconnect. Not earth shattering but definitely noticeable and worthwhile --- especially if things like subtle nuances matter. The RSM’s will look exactly as they do in the pics, minus the 1/8” gap between the monitors and the stands. We will still offer the Reference Woofer Monitor 1.0 separately for use with other bookshelves, but building them as a floorstander saves the owner serious money as well as improving the sound quality! ”


There are different finishes available – see below.




Reference Standard Monitor 1.0 Bookshelf

Standard – Sand (Light Beige)


Reference Standard Monitor 1.0 Bookshelf

Standard – Cappuccino (Med. Brown)


Reference Standard Monitor 1.0 Bookshelf

Premium – Zebrawood


Reference Standard Monitor 1.0 Custom Height Floorstander

Standard – Sand (Light Beige)


Reference Standard Monitor 1.0 Custom Height Floorstander

Standard – Cappuccino (Med. Brown)


Reference Standard Monitor 1.0 Custom Height Floorstander

Premium – Zebrawood


Reference Woofer Monitor 1.0

Standard – Sand (Light Beige)


Reference Woofer Monitor 1.0

Standard – Cappuccino (Med. Brown)


Reference Woofer Monitor 1.0

Premium – Zebrawood




Reference Standard Monitor 1.0 (BS or FS) Specifications:

Frequency Response: 100-20,000 Hz +/- 2dB/1w/1m
Sensitivity: 86dB/1w/1m
Rated Clean Power: 40w
Peak Clean Power: 75w
Max SPL Peak: 101dB/1w/1m
Dimensions: 12” h x 7” w x 12” d
Weight: 19 lbs ea.

WooferMonitor 1.0 Specifications:

Frequency Response: 30-150 Hz +/- 1.0dB/1w/1m
Amplifier Power: 300w
Max SPL Peak: 104dB/1w/1m
Dimensions: 16” h x 15” w x 16” d
Weight: 44 lbs ea.



During this review I compared the shelby+kroll Reference Standard Monitor 1.0's Bookshelf and a pair of shelby+kroll Reference Woofer Monitor 1.0 to my personal speakers that currently go for about $50,000 per pair.  I said the shelby+kroll system compared very closely and maybe even better in terms of imaging and soundstaging. Perhaps the biggest difference is that the Wilson’s will play a little louder at full throat than the smaller sk’s.


Finding any speaker with a range that goes all the way down to 20 Hz requires some diligence – and usually a whole lot of money. Finding one that sounds like these and start at $10,000?

We have always preached that there is no perfect speaker or even BEST speaker (with no apologies to YG who claim to make BEST speaker on the planet). SK agrees. A pair of huge $200,000 speakers may sound great in one guy's big room, but we can guarantee that the same would probably sound awful in an 8x10 room with a 7 foot ceiling. Also, the same speaker that sounds terrific in a certain room to a certain listener may sound awful to another person listening to the same speaker in the same room. A third point is that almost all speakers, or any component for that matter, is always a series of compromises and tradeoffs. Kroll agrees with that, too.

In a particularly honest and transparent comment, on the shelby+kroll website it reveals this startling Q & A: 

So what did we compromise?

1) 120dB maximum output. Within their power range, the Reference Standard Monitor 1.0's are remarkably dynamic, can hit 100dB and do so extremely cleanly. We willingly gave up the ability to crush your skull. If that is your highest priority, any pair of pro sound PA speakers can peal your face back with 20 watts. We are operating under the premise that anyone viewing this website values quality over quantity.

2) The ability to play in a very large room. There is only so much air a diaphragm (that weighs less than 5 grams!) can move. The Reference Standard Monitor 1.0's cannot pressurize a very large room. They still sound really good, but if you have a really big home theater/listening room, you
will probably want to wait for one of the bigger models if you like to crank it way up.

3) and that’s about it.

When we asked, Tim said that his recommended max room size is 30X20X20 if you are playing all genres of music.
Recommended max room size for a single RWM 1.0: 18X15X10. He added that although the sensitivity is an average 86db, the RSM is extremely easy to drive, much more so then a lot of 89-91dB speakers with complicated crossovers.

Worthy of a repeat: If you purchase these speakers factory direct, they offer a 30-day money back guarantee! If for any reason you do not like these speakers, they offer a guilt-free return guarantee. That folks, is a no-brainer.


We think we’ve discovered something special here. If you have a small to medium size room and at least a 25 watt per channel amp, these are pretty hard to beat.


We are always looking for ways to save you, our dear readers, some money. Note that this review includes a PAIR of subwoofers, but YOU might not need a pair. If you have a smaller room or mostly listen at low levels, you could get away with a single sub and that would save you $2,550 in standard finish. Who's lookin' out for ya, baby?

It’s seldom that exorbitant claims made by high-end companies meet their hype, but in this case, well, it’s not all hype.


It's been several months since we have bestowed our rare Maximum Mojo Award on any product, but in this case - it fits!

Congratulations to Tim Kroll and shelby+kroll.



The associated equipment was as follows:

System 1

Wilson Audio Alexia

Evolution Acoustics MM3

Pass Labs XA-160.5

EMM Labs Switchman3

Playback Designs MPS-5

EMT 948 turntable with custom vDh cartridge

Studer A80RC MkII ½” and ¼”

Sonoma and Pyramix Digital Audio Workstation

Digital Audio Denmark AX24

MSB Tech Platinum Signature DAC IV with Diamond Base

JPS Aluminata Power/Speaker/Interconnect cables

Wave Kinetics A10-U8 and 2NS footers

System 2

Joseph Audio RM25si Mk II

YBA Integre DT

Exemplar modified Oppo BDP-83

Merging Tech Emotion Music server

Mytek Stereo192 DSD


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