First build: Woden Sperrin

Hi all, I just completed my first speaker build and thought it would be idea to share some pictures and thoughts about the process as there doesn't seem to be much coverage of this design.
I work as a sign maker so I'm fairly handy with building stuff, but have only really dabbled with basic woodwork almost always in MDF for a famous coffee shop chain. Crucially though, we have a 2m x 3m CNC router which definitely gave me a head start over most first time builders!
I wanted to start with something fairly simple, but a bit more exciting than a basic bass reflex which pointed towards the frugel horn or BK-12. A major consideration though was minimising angled cuts as I have no (easy) way of doing them with my equipment. This led me to Woden Design and their smallest Fostex design, the Sperrin for FE103EN, which can be made entirely with right angled cuts.
A few emails to Scott later and I had the nicely detailed PDF plans, which I drew up in ArtCAM ready to feed to the router.
As advised I used 18mm birch ply for most of the panels, but for the front and feet I used a piece of blocked beech worktop which and been sat in my garage for months (purely for aesthetics).
Since I had the router I decided to cut slots and rebates into the side panels to keep everything alighned and as square as possible, but not having many clamps had to glue only a few pieces at a time. More to follow, trying to keep post size sensible!


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Despite chosing this design for the lack of angles, I much preferred the look of a single angled deflector over the stepped version so I gave my few offcuts to a friend of a friend who had some woodwork experience to try and cut them. Unfortunately this didn't work out, and with no ply left I had to use the beech worktop by layering pieces toether with dowels to keep it aligned. purely by chance the layers added up to almost exacty the required depth and only needed a bit of sanding to match the rest, with the added bonus of looking pretty cool.
With all the parts now cut it was time to glue the other side panel on, this was the only tricky part of the build as there are many parts to get aligned with not a lot of time to work as the glue dried quickly. I will also be using a lot less glue on any future builds, once the clamps were applied there was some major ooze going on, and some frantic scraping trying to clean it up before the glue dried.
The front panel (baffle?) was last to be installed so the wire and felt damping material could be glued in place. This was nerve wracking as well as they were a very tight fit, and needed a fair bit of 'persuasion' to close up all the gaps. I also made some new smaller feet with my last piece of material as the single block didnt look great.
Assembly now complete it was time to take them home for testing :D


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Thanks Scott, you were right about the room being the cause of the LF dips and humps. I moved them to a different wall and the response changed completely, been having fun tinkering with them trying to dial in the sound, but still seems like plenty to learn!
After a week or so of testing, tweaking the stuffing and placement I'm now pretty happy with the results, and on the right track they really are spectacular. I had been running in the drivers mounted to just a flat panel which sounded plain horrible, but once in the cabinet they were transformed. Nice and clean, plenty of bass (for me) and amazing stereo image and seperation. They do struggle when things get busy but I'm certainly not complaining since they are designed for 'small piece acoustic' music. Despite their limitations it really is amazing how much performance Scott has managed to squeeze from such a tiny driver, and I'm excited to have a crack at one of the larger models :D


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I agree with your listening observations, great imaging and separation. Great with vocals and acoustic instruments. I find the treble a bit dry and the sweet spot narrow. The published response graph shows a flat on axis response. The MA Pluvia 7 in contrast have a rising response up top but not overly so, therefore they are better for off axis listening and less fussy with listening position. The Fostex's mid-range is its strong point.
Thanks for sharing the pics Tipper, and good to know that you are enjoying the sound.

Despite their limitations it really is amazing how much performance Scott has managed to squeeze from such a tiny driver, and I'm excited to have a crack at one of the larger models :D

Indeed, Scott has a good number of designs that the DIY community has been enjoying over the years. Thank you Scott! :)

And on your intentions to "have a crack at one of the larger models" - chances are high that it will be a rewarding experience, but beware, DIY audio projects can be very addictive... and they can go beyond single driver speakers... amps, preamps, WAWs and multi-ways, DSP and what not!
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Congradulation on your first build.I wish I had access to a CNC router when I built my Pensil 10p which I like alot considering it's limitations.
I'm thinking about a second build and I've been reading good things about BLH and low wattage tube amp which I use.The thing that turns me off about the BLH enclosure is their size. My listening space is rather small 10 feet wide with an open back to a larger room. I came across an article written by Martin King on the making of a Compact BLH with good bass which appealed to me due to it's size which is about the same as the Pensil 10p.
Upon further research I came across the Sperrin enclosure on the Woden site and thought that this plan would suit me fine since I would have to have it altered to take the Alpair 10p or possibly an other driver eg:Jordan Eikona 2.Can this design be altered?
My question to the OP is:How do you find the bass on the Sperrin?
My question to Scottmoose is:Would this design benefit from a rear mouth since I can corner load?

Bass is hard to quantify, obviously not chest thumping impact but far more than I expected from such a small driver and plenty for their intended use (acoustic and vocals.)

I sold them a while back to fund the next project, Silbury with Alpair 10.3 so can't give you much more info unfortunately but I was very impressed, wish I had kept them and will likely buld another set at some point.
Interesting you asking about adapting them for the 10p, I actually contacted Scott about doing exctly that but never heard back and ended up making the Kirishimas instead. Would still be interested in a Sperrin 10P if its possible though, let me know if you get anywhere with it.
Hi Tipper,
I'm sure something can be done to put a 10p in the Sperrin.The Sperrin looks very much like the Martin King Compact BLH, which is for a fostex driver that I can't recall.
I will keep an eye on this post and see if Scott replies.
BTW I was surprised that you sold those Sperrin so soon after being built.
No the Sperrin didn't hang around long, I hadn't made anything like this before so they were a sort of test run to see how I got on before trying a larger more complicated design.
Would have kept them if I had more space, they were excellent. My boss spotted them in work and offered enough to cover my material and parts cost so that was that.


Yes the Silbury's were finished a few months ago, they looked fantastic but I wasn't keen on the sound, could have been a room thing but I just couldn't get them 'right'.
Have since made the Kirishima and much happier with them, just waiting on a tube amp now for the icing on the cake.


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Apologies, snowed under with work & not in 100% health (albeit probably better than Dave has been), so I'm afraid I've been struggling to keep up with things at present, other than sporadic posts.

Sperrin has no connection to Martin's horn; I've been meaning to revisit it to move it closer to the regular Woden typology. The Alpair will certainly not work in it however, nor is it especially well-suited to this general configuration of horn. I could work something up, but frankly I think other options would be a better approach for those units.
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I'd love to hear more details about what you did/didn't like about Silbury vs. Haruna. I know these things are subjective and difficult to express, but I'd appreciate it if you gave it a shot anyway.

Side note: I have gathered (perhaps incorrectly) that Silbury is intended to be placed closer to the back wall than as pictured above.
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Man, those are huge boxes and would not be good for my listening space.I was interested in the Sperrin because of it's smaller footprint.
I've read good reviews on the FHXL but even those have a bigger foot print than my Pensil 10p which are about as big as I will go.
Scott, what BLH enclosure would you recommend?
I listen to some rock and the Pensil 10p don't do rock as well as my heavily modified Klipsch Forte ll.The Pensil 10p are excellent with vocals and single instruments.
I now understand what is meant by``the speakers are moved out of the way or speakers disappear`` They have good imaging and soundstage but they don't like Zeppelin!!
I would not consider them all-rounders.