2. Willis Room, the Ultimate Test

The Camel II speakers faced their ultimate test during a Melbourne Audio Club demonstration in the Willis Room. Paired with the superb Aurora Audio Signature 2x 70W Class A amplifier, SMSL D6-S DAC/preamp, and Arthur's Cambridge Audio CD player. This system, renowned for its e ortless power delivery, exceptional transparency and natural musicality provided the ideal opportunity to assess the Camel II performance under demanding listening conditions.

Members of the DIY group were impressed from the outset, noting that the speakers sounded excellent during setup. The positive reaction from club members reinforced the success of the Camel II project. Comments received from club members are presented below.

Michael D commented, "Having had glimpses into the design process, my expectations for the finalised Camel II were very high. Evaluated against my core priorities: tonality, resolution and dimensional staging, the Camel II delivered a performance that although different, impressed me as much as the active ATC SCM50 ASL we reviewed in 2020. The tonality is precisely balanced, offering a smooth, fatigue-free top end alongside an incredibly articulate, note-perfect bass response. The midrange is a standout, delivering exceptional clarity and natural timbre that allows for hours of effortless listening. When the recording allows, they throw an expansive, holographic 3D soundstage with precise imaging and space between instruments. From subtle micro-nuances to huge crescendos, the Camel II handles dynamics effortlessly without ever losing its superb detail. An awesome, musical speaker!"

Alan H commented, "Wow this system sounded better than any commercial high end systems I've ever heard in the Willis room, costing tens of thousands of dollars. The level of talent in the club's DIY group is incredible. You must be thrilled with the result."

Mak P commented, "The clarity was insane, with not the slightest hint of distortion even at higher listening levels. The presentation was exceptionally detailed, and effortless, making these speakers a genuine pleasure to listen to for extended periods. The synergy between the in speakers, amplifier, and DAC was outstanding, resulting a b a l a n c e d , coherent, and highly engaging musical sound. "

Derek L commented, "The speaker and amplifier sounded lucid, transparent and realistic with excellent bass and treble extension. It timed particularly well and was very engaging. The piano, with its complex combination of string harmonics, dynamic range, and resonant soundboard, is particularly challenging to reproduce accurately. Yet the Camel II system conveyed the texture of the strings and the rich, resonant character of the piano's body, resulting in an exceptionally realistic sound. Given the challenges of the Willis room and the full capacity it was at, this was an excellent achievement."

Philip N commented, "I thought the speakers sounded amazing! Great depth of sound from lows to highs. Beautiful tonality across many instruments' types including vocals. The low end is particularly good with an excellently tuned reflex cabinet. The Camel II impressed me so much that I've decided to build my Oval MK II using the same woofer as the Camel's. I suspect an amplifier upgrade may be next on the list!"

Dave P "Given the depth of knowledge and the development process of the Camel II speakers it is no wonder they easily match, and would probably exceed, the sound quality of any speaker I have heard ever. I truly loved listening to them whatever genre of music was played."

3. Driver Selection & Testing

The driver selection process for the Camel II project focused primarily on the midrange, as this band carries the majority of vocal and instrumental content.

A total of fourteen different midrange drivers, ranging from 4.5-inch to 7-inch units, were evaluated during this phase. Nine of the drivers that were evaluated were from the SB Acoustics range, as the manufacturers multiple different cone materials featuring the same motor design. The DIY group extends thanks to Richard S, who generously provided a wide selection of SB Acoustics midrange drivers for evaluation.

This stage of development was particularly rigorous. To ensure consistency and objectivity, a dedicated test enclosure was constructed, allowing each driver to be measured and auditioned under controlled conditions. Evaluation included blind listening sessions conducted by the group. The results had a correlation of approximately 80% between subjective impressions and objective measurements.

Following these comprehensive group evaluations, the following drivers were selected, a 10" Satori papyrus bass driver paired with a 6" Satori Textreme mid-range driver and a Satori Textreme tweeter.

4. Acoustic Parameters & Enclosure Design

With the physical drivers selected, the group set out to determine their precise Thiele/Small (T/S) parameters to establish baseline calculations for the enclosure volumes. While manufacturer-published specifications were readily available, the group opted to physically measure the drivers using both the ARTA and DATS measurement systems. Although the various design software programs and test systems yielded slightly di erent data, they provided the necessary parameters to finalize the internal enclosure volumes.

Once the volumes were established, the group turned to the visual and architectural design of the cabinets. The group heavily discussed the acoustic value of incorporating non-parallel faces to minimize internal standing waves. Sach Sackl, the group's architect, presented several unique design drawings. The group ultimately selected a form that established striking proportions and complex geometric angles in line with solid architectural and acoustic design principles. As well as a construction that the group could successfully fabricate.

5. Advanced Cabinet Construction

The physical execution of the cabinets introduced significant engineering challenges. The design called for complex 15-degree angled back panels on both enclosures, requiring highly accurate technical drawings. Stephen Myles provided the necessary computer drafting and CAD skills to resolve these layout requirements. phase involved evaluating various reflex port constructions alongside the strategic placement of internal damping materials to suppress unwanted mid-frequency energy from exiting the bass port.

To suppress cabinet wall radiation and internal resonances, the group implemented a heavy constrained-layer damping (CLD) panel topology. Stephen researched the implementation of this technique, locating online documentation from independent DIY builders who had experimented extensively with the concept. The front ba le with a total thickness of 37mm, comprised of 25mm MDF plus 12mm plywood. The rest of the cabinet consisted of composite panels, with a structure of a double-layer laminate of 12mm plywood and 12mm MDF. For the bass enclosure, the layers were laminated using a rigid PVA glue, while a non-resonant flooring glue was selected to bond the panels for the mid-range enclosure.

Constructing a double-walled enclosure featuring compound angles and non-parallel faces proved to be a challenging project compared to the standard, right-angled single-layer boxes typical of most loudspeaker construction. The build required numerous Saturday working bees alongside several extra construction sessions to complete. While high attendance meant that not everyone could physically work on the enclosures at one time, Ian Game was consistently on hand to assist with assembly. Crucially, navigating the demanding woodwork and complex joinery may not have been possible without Ron's extensive background and practical experience in woodworking and loudspeaker construction.

6.Tuning, Measurements, Crossover Refinement

Once the cabinet assembly was completed, the physical drivers were mounted into their respective enclosures so that acoustic testing and port tuning could begin. The initial testing The electrical crossover design was developed in two distinct stages. Initially, Ron engineered a series 1st-order crossover to handle the transition from the bass to the mid-range driver, paired with a 3rd-order network between the mid-range and the tweeter. Using his custom variable crossover test rig, Ron dialled in a solid baseline configuration that allowed the group to begin immediate listening tests and evaluate the initial system balance. With the speakers fully assembled, Phil Norman used his specialized turntable and test gear to capture comprehensive, high resolution o-axis acoustic measurements. This precise measurement data was then imported into VituixCAD simulation software. Ron, Damian and Stephen used these simulations to further refine and optimize the crossover network. Following the simulation updates, Damian spent extended sessions listening to the revised filters. Final listening tests and final adjustments were completed by the group with a wide variety of music.

7. Finishing & Final Presentation

The final phase of the project focused on the aesthetic and cosmetic finishing of the enclosures. The exterior pine sections of the cabinets were sealed and stained in dark tones, while the front ba les were wrapped in a modern carbon fibre vinyl wrap. Custom grille covers were also fabricated to protect the face of the speakers.

The visual transformation was dramatic. The application of the darker stains and carbon fibre wrap completely changed the aesthetic character of the speaker, resulting in a premium, visually striking finish. Because of these darker tones, the large enclosures managed to visually "disappear" into the room environment while maintaining an elegant, high-end architectural presence.

MAC Audio Action/DIY Group

The April monthly meeting saw the second instalment of the idea put forward by Tony Fisher late last year and first trialled at the January meeting, when Tony and Bailey White presented a collation of songs that had, for one reason or another, played important parts in their lives. It marked a significant innovation in the structuring of the club's monthly meetings, one that I supported strongly in my review in the following MAN (see ? 606, February 2026). Last month it was the turn of David Chambers and Matt Jelicich to give their spin on the idea.

Dave tells me that he and Matt wanted the night to be di erent from any gone before at a monthly meeting: sustained audience participation, giveaway lollies, a darkened and more intimate space for listening, videos being played as well as music, a quiz at the end, and the night extending over a single session, finishing at 9.30 pm. And indeed it was di erent! Whereas Tony and Bailey's January session was sequential, with Tony presenting discourse (or was it 'discourteous'?) with Henry Bolte, 38th premier of Victoria, was priceless.

Matt captivated us with his description of growing up in Auckland in the 1950s, and enlivened that understanding by playing snippets of what he heard on the radio at the time. When I entered the Willis Room around 7:30 I was intrigued by what was hidden under a tea towel in the middle of the stage, between the two chairs. Matt, in a demonstration of faultless timing and e ect, unveiled it to be the ancient (but still working) valve radio his parents owned in the 1950s and that he had grown up listening too. He surprised us even further by then revealing the very radio he had as a teenager and an intriguing contraption that not only played the radio but, by turning it over, 45 rpm singles. Genius! If only all of our presenters at monthly meetings could be so clever, so thoughtful, so aware of the varied needs of an audience to be educated and entertained.

before the tea break and Bailey after it, Dave and Matt took a di erent approach, playing tag-team and alternating in their presentations and choice of songs. They took Tony's innovation of darkening the Willis Room for the listening session one step further, having a podium at the front with their chairs astride a small table and on it a desk lamp, a bottle of (alcohol-free) chardonnay to the side to provide the necessary libations. Brilliant stagemanship!

The presentations were masterful, not only in the way Dave and Matt showed the progression of their musical interests over the past three, four, five, six, seven decades but also in the way they captivated the audience. Two lifetimes of musical interests were laid bare, in the most honest and e ective and entrancing way possible. Dave regaled us with stories of a young life in Alexandra and Eildon in north-eastern Victoria, his running a restaurant there, and living with music all the time. The names of a few old girlfriends cropped up in conversation, something that only added to the personal nature of the presentation. His description of a brief Although Dave and Matt dominated the show, a number of other club members cannot remain nameless in their contribution to its success. Bailey was in the background, handling e ortlessly the technology that stitched everything together. It was quite an effort, as Dave and Matt alternated in their presentations and included snippets of selected tracks and, in some cases, video clips to illustrate a particular point. An analysis by a young female singer, voice coach and YouTube sensation, Lolli Wren (aka the Fairy Voice Mother), was one such video. She undertook a thought provoking analysis of the song 'Hocus Pocus' by the 1970s Dutch prog-rock band Focus. The lyrics go along the lines of:

"Joladadijoladadijoladadijoladadi
Joladadijoladadi-jo-o-ooh
Joladadijoladadijoladadijoladadi
Joladadijoladadi-jo-o-ooh
Oooooh-oooooh-oooooh-oooooh".

And I thought Little Richards' "Awopbopaloobop Alopbamboom" was meaningless. But then he didn't yodel them... On the other hand, Chris Norton did attempt a yodel (at Dave's invitation), much to the delight and amusement of all. Chris Mogford was the second noteworthy assistant. Playing a role akin to that of Dugald McAndrew in Rockwiz, Moggie dished out the lollies to those in the audience who answered correctly the many questions and points of trivia posed throughout the night by Dave and Matt.

Hugh was the third essential ingredient. His Maya amplifier and custom-modified speakers sounded magnificent on the night, handling with aplomb tracks sung (or yodelled) variously from Dean Martin to Thijs van Leer, the Beatles to Marty Robbins, Leonard Cohen to Gene Autry, even Yma Sumac for added effect too.

So, to conclude, it was a superb iteration of the idea proposed by Tony Fisher late last year. I wouldn't want to have this type of session every monthly meeting, but the two versions we've had this year have been so successful that the format must now be considered an essential component of our annual program. For once, we got to hear the personal stories behind the choice of music, a case where the music really DOES come first and the equipment second. We get to learn a little bit more about what makes our fellow members tick, what their musical interests are, and how those interests have evolved over time. And often we get to learn something about the music itself. Bravo.

And now to actually finish, with a concluding observation. Dave and Matt started at around 7:45. They were finished by 9:30 or so (maybe 9:45 if we include the end-of-session quiz), as they had planned. We then broke for tea. No one died of thirst during the single, uninterrupted session of around 2 hours. No bladders were ruptured and urine spread across the floor. No one looked constantly at their watches or the ceiling or their shoes or the fly on the wall, waiting in boredom for the whole thing to draw to a merciful end when we could all go home.

If we start promptly and club business is dealt with e iciently at the beginning, a single, uninterrupted sitting of under 2 hours allows the presenter(s) ample time to communicate what they want to say and then provides an opportunity for attendees to retreat out the back and chat over a cup of tea, discuss what had just transpired, and catch up with the presenter or with old friends. These are the social and comradely elements of the club, ones that in my view are just as essential as the showcasing of specific items of equipment.

Paul Boon