Illuminator-5

This will be my attempt to make the very best we can get from ScanSpeak drivers*. Who knows what the future will bring, but until then, these Revelator and Illuminator drivers can make recorded music alive in our living rooms.
Why 5-way? The thing is that a 18WU driver has a cone area of 154 cm^2 and a dome like the D3004/602010 some 7 cm^2. Any driver will start beaming at a frequency having a wavelength equal to the diameter of the cone, thus for the 18WU it will start beaming around 34.400/14 = 2.457 Hz. On paper this all goes well as long as we stick to a point of crossover somewhere around that frequency. And this has indeed been the prescription for countless speakers over the years, the classic "6+1" set-up. It's a compromise as any speaker is and it's OK! They're doing well, but they also have a sound that is characterised by this sudden change in dispersion pattern going from 150 to 7 square centimetres. The Ekta and SP44 and Classic 3-ways sound very differently because they all have this small 2-4" middriver with a much different dispersion in upper mid/lower treble, creating a presence the standard 6+1 doesn't. This "presence" reveals detail and to some it may be too much detail because source material may not be too good - or the overall front-end, amps, CD-player, etc., is not up to the task. In this construction we're talking as few compromises as possible.
In reality, this is just the classic 3-way like ScanSpeak SP44, Ekta and SP38, added a bass module. For some reason this is rarely seen in commercial speakers, rather a 2-way with added sub module and I think the simple reason is cost.
As mentioned in my recent Discovery 12W file, there at a lot of good 4" drivers around. A good 4" driver is much better handling the upper midrange and lower treble compared to any 6-7" driver. That is the ~800-1300 Hz range. Treble starts at 1280 Hz and to some it comes as a surprise that our 6" drivers very often handles treble. The most cost-efficient way of dealing with this is the Classic 3W, where a 3-4" driver bridges the two main drivers like my SEAS Classic 3W and Discovery Classic 3W. If we do this we can also increase the size of the bass driver to an 8" and get an even bigger soundstage.
Initially I made one speaker with the 12MU midrange driver and compared to the Illuminator-4 (4-way with 7100 tweeter, not published) speaker and the result was more surprising that I had expected. The 5-way could play even louder - and the Illuminator-4 can play loud. The 5-way would play a saxophone until it was painful, not because it sounded bad, but just because it was loud. Really loud.
Another thing I've noticed is that with a high-quality upper mid-driver, we start worrying less about the tweeter. Not that we can use an inferior el-cheapo tweeter, only that swapping tweeters really doesn't seem to pay off that much, where in a classic "6+1" we're more dependent on a really good match to the mid-bass, and this doesn't always come from using the most expensive tweeter, rather one that makes a good blend with the midbass. Tweeters may show us all the things we think is good, but make a poor partner to whatever midbass we aim at. Synergy is the keyword, not some intrinsic "on-paper" quality. I've often had the question why I don't use ribbons more and I generally find ribbons hard to integrate well with a 6 inch mid-bass.
Now, two 12MU mids certainly don't come for nothing, but here we're not talking cost-efficiency, rather what we can do if we want the best from the Illuminator drivers and the more even change in distribution pattern of drivers is paying off in the smoothest midrange I've so far hear from a ScanSpeak set-up.

* That is, within a given footprint! We might do even bigger/better(?) from a tower with multiple 10" bass drivers and d'Appolito arrangement of 22W/18WU/12MU/dome(s), but this speaker will fit in a normal living space without totally dominating the picture.

Speaker basics:
5-way speaker system or you could argue the 22W not having a high-pass filter makes it a 4½-way due to the use of two bass drivers having different low-pass functions.
Bass reflex, closed box and aperiodic tuning is used for lower bass, upper bass and middriver respectively.
Points of crossover; 80, 180, 900 and 2800 Hz, 2nd order LR, mids and tweeter time-aligned.
Impedance: 4 Ohms, minimum 3 Ohms.
Sensitivity: 88 dB/2.8 volts, 1 meter.
Amplifier requirement: Minimum 50 watts.
Power handling: A lot! Read here.

You cannot use any other driver than those specified, or you need a new crossover - and I can't help. Any change to front panel design and drivers' placement and alignment - and you need a new crossover. Sorry, can't help.

Let's take a break here! The 12MU midrange driver. It's a marvel of engineering! Everything we've learned about speaker drivers over the last century seems built into this Illuminator midrange driver. Long-fibre, one-piece molded paper cone, low-loss suspensions, symmetric drive, low-reflection magnet system, ventilated voice coil, highly open frame structure, etc. All seen before, but rarely in one single unit.
And it doesn't stop here: The under-hung voice coil and titanium voice coil former with virtues of paper bobbins*, but with much better power handling. On top of this, selective rear coating of the cone and around the rim of the outer cone a carefully applied ring of damping glue to handle upper-mid resonances, something many 6" drivers could benefit from, but it takes time to do it right - and time is added production cost. Last, but not least, the low-loss, light-weight coated foam surround. The coating will ensure many years of service, don't worry.
* - and not the common aluminium voice coil formers that reduce transient attack acting as a brake and reducing Qm (one of the many reasons for modern dull hifi).

Please notice you cannot use any other drivers than those specified. Please read: crossovers

All things start with test set-up for fine-tuning cabinet design and a birds nest crossover to make it as simple as possible.
In particular tweeter and midrange front panels can make huge differences and jeopardize drivers' frequency response and require equalising in the crossover, something that can mostly be avoided by proper design.

I can't tell you what this Illuminator-5 sounds like. Like food and wine, you'll experience something different from me. Auditive perception is just as subjective as taste and smells.
I've already told this speaker can play seriously loud and deliver a punchy bass, but what surprised me the most was how low it can play. Thanks to the dispersion of the small midrange and the presence it creates, we don't loose grip of the music when listening at low levels. We maintain the ability to catch subtle nuances and tonal colour even when turning down the volume to quite low levels.
I'm sure I'll have the question on a smooth midrange and silky treble. These phrases really mean nothing, but YES! It's got a non-aggressive midrange, all of the midrange. Even with the tweeter tuned to a fairly flat response, you'll listen to treble, not tweeter. We really shouldn't be able to hear the tweeter as such. If we do, it plays too loud. And yes, it does vocals really well too. I've tried all my troublesome vocal recordings and this speaker just doesn't care. One thing that can turn vocals aggressive is beaming of the midrange driver, for full-range drivers this is often heard as the "midrange shout". This phenomenon is effectively eliminated by the small 12MU driver. The 12MU also creates a better placement of vocals and instruments in space than the usual 6+1 set-up. It simply creates a better 3-dimensionality.
I run these speakers from my bi-amping set-up: GlowMaster KT88 for the MmT section and a Hypex digital for the bass module. The Illuminator-5 likes a little more power than my ATS4 speakers, I guess we're talking 1-1½ dB reduced sensitivity compared to ATS4, but it's only one click more on my attenuator.
Setting up the speakers in our living room was unproblematic. Same place as ATS4 and a little experimentation on toing-in made it.

What the speakers will do in your listening room is impossible for me to tell. Only thing I can advice not to do is place them up against the front wall and not in corners. The former will reduce sense of depth and transparency and the latter make bass too boomy. In that respect the Ill-5 is no different from any other speaker.

I didn't only listen to John Scofield during fine-tuning the Illuminator-5 speaker. Sometimes I just dig out all my LPs of a particular artist. These LPs are mostly music of the Eighties and I fancy challenging my past to hear what music last and what doesn't. Well, some of these records are very much of the Eighties, very electric. Apart from Scofield we also went to hear Chick Corea's Electric Band at Montmartre in Copenhagen and I've never seen so much electronics on a stage. John Scofield visited Montmartre not too long after the release of my favourite LP, Still Warm. Some of the music does stand the test of time, some doesn't. What the Illuminator-5 does is recreating the dry and fat low-end bass that followed this musical period.

Making drawings from the Illuminator-5 would take ages, thus some images with added dimensions. This really provides all the basic info needed to making the cabinets. Click images to download files.

Now, making the cabs above takes time! Many, many hours of work. The thing is that you get the same sound from making cabs much simpler like the DISC-4 speakers.
AS ALWAYS: Stick to front panel dimensions* and drivers' placement. Keep internal volumes +/- 5% and you're safe. Whatever fancy dress you come up with for your speakers is fully up to you.
*: The front panel reflects sound and depending on size, shape and the drivers position, you'll get a frequency response different from any other panel or placement. Thus, the crossover is designed in such a way it takes into account the response of the driver on that particular front panel. Any change to this - and you need a new crossover. Any other driver than those specified will produce a different response and need its own new crossover. And here I cannot help without having your speaker in my workshop. Any change to these few basic things, and you're on your own.

Ports:
With the kit you have 4 ports @ 68 x 220 mm, 2 ports @ 50 x 145 mm and 2 ports @ 35 x 68 mm.
Please read here about port dimensions: http://www.troelsgravesen.dk/tips.htm#PORT_DIMENSIONS_ You may find other tips useful from the same page.
Two 68 mm ports are used for the bass cabinet, use full length.
One 50 mm port is placed in middle of mis cab rear panel, cut to 10 cm length and stuffed with a roll of 10 x 20 cm acoustilux.
One 35 mm port is placed on rear panel of 12MU cabinet and stuffed with a roll of 60 x 80 mm acoustilux.

Make a single bracing like seen on photo. The holes are Ø 107 and 75 mm. Place the bracing in the middle of the cabinet.

Gluing the front panel was easy as we have the bracing to hold the four clamps. Otherwise, gluing pyramids are a pain!
Right image: The easiest part, the upper-mid cab. All made from 15 mm BB except for front and rear panels where I used 20 mm. Same goes for the tweeter cabs.

Upper-mid cab damped with bitumen pads.
The kit includes a small 35 mm port for the 12MU cabinet. At the time of the photo shoot this wasn't mounted yet.
Stuff the port with a roll of 60 x 100 mm sheet of acoustilux.

Gluing the side reinforcement panels is a pain! Make a sheet with a 30 deg cut and fix with clamps to the upper (red arrows on image) panel to avoid it sliding upwards. Add a clamp to prevent the panel from sliding sidewards (green arrow). Then finally we can apply pressure to the panel (blue arrows), but make it slow and keep checking edges. I made the side panels slightly bigger than needed. Easier to sand off than to add...
The side panels were made from laminating 20+10 mm BB (30 x 200 x 800 mm block) and cutting it 8 deg from both sides and sawing the rest by hand as my table saw only does 75 mm height. Quite tedious. The cuts were smoothed by using the router sliding on an 8 deg. rig.

Added lacquer and fully mounted playing on top of test bass modules.
Getting the stuffed port for the 18WU in place helped considerably compared to the closed box test cabinet. Better dynamics and more sense of depth to the bottom end though this may sound strange. The 12MU cab is closed at this point in time, but a small will be added here too to hear what happens.

At this point I had to start thinking of the MmT crossover layout to know the exact dimensions in order to design the rear part of the bass modules. To keep overall height the same as the ATS-4 I decided to omit the 50 mm base support and place the bass crossovers inside the bass module. Changes to the bass section crossover is unlikely once in place and no need for quick access.

Doing internal panels for upper bass enclosure and marking drivers' placement on front panel.

Right: Testing both side panels.
All panels between the two side panels were cut to 325 mm width at the same time to make sure of a tight fit.

Rear cover panels and first time final set-up and - as always - sounding better than the prototypes.

All internal panels are damped with 8 mm felt material supplied with the kit. Exception is panel behind 26W driver where the crossover is placed and the 26W upper panel towards 22W bass driver. In the compartment above 26W, place a roll of 30 x 100 cm acoustilux.
On top of the bass crossover on rear panel behind 26W driver, place two sheets of 25 x 30 cm acoustilux.
18WU cabinet: Rear compartment: Cover the floor, sides and rear panel with acoustilux. Front compartment: Cover floor and sides with acoustilux.
12MU cabinet: Cover sides, rear and half bottom and top panels with acoustilux. Bottom and top only half due to limited space around 12MU driver.

The Illuminator-5 has a potent bass and don't place the speakers too close to the corners. Tilt the MmT cabs according to your listening height. I have some 10 mm blocks under all sections to suit my 3 meter listening distance. The 18WU on-axis may be a little above listening height, where 12MU and D3004 should point at your listening height. My speakers a slightly toed in so that I can just see the inner side panels.
Take you time finding the best placement and tilting of upper-mid and tweeter cabs! If you have too much or too little bass, there's nothing I can do about it. Your room is an amplifier and a vital part of your system.

A few comments on MEASUREMENTS before you start interpreting all the readings below.
First of all, if we think measurements will tell us how a speaker sounds, we're wrong. The perception of sound is way too subjective to be reflected in any measurements we can perform. A loudspeaker system is meant to give us a satisfying idea of an acoustic event and for some people a pair of 5 USD ear-plugs are enough, others spend 200 kUSD on a truly full-range pair of speakers - and the latter may not be happier than the former.
Measurements may give us an idea of tonal balance of a system, i.e. too much or too little energy in certain areas. Measurements may tell us about bass extension if far-field measurements are merged with near-field measurements. In addition to this, ports may contribute to bass extension. Most of us diy'ers do not have access to an anechoic room for full-range measurements from 20-20000 Hz.
What cannot be seen is what kind of bass performance we get in a given room. Bass performance is highly dependent on in-room placement of your speaker and the same speaker can be boomy in one place and lean in another. Actual SPL level at 1 meter distance and 2.8V input is useful for en estimate of system sensitivity and combined with the impedance profile may give an idea of how powerful an amplifier is needed to drive the speaker to adequate levels.
What measurements do not tell is the very sound of the speaker unless displaying serious linear distortion. The level of transparency, the ability to resolve micro-details, the "speed" of the bass, etc., cannot be derived from these data. Distortion measurements rarely tell much unless seriously bad, and most modern drivers display low distortion within their specified operating range.
Many people put way too much into these graphs and my comments here are only meant as warning against over-interpretation. There are more to good sound than what can be extracted from a few graphs. Every graph needs interpretation in terms of what it means sonically and how it impacts our choice of mating drivers, cabinet and crossover design.
What measurements certainly do not tell is the sonic signature of the drivers, because cones made from polyprop, alu, Kevlar, paper, glass fiber, carbon fiber, magnesium, ceramics or even diamonds all have their way of colouring the sound.

Above response graphs from some of the initial stages of crossover fine-tuning from prototype baffles. To the left the smooth roll-off profiles of the 18WU and 12 MU drivers. To the right the response graphs of individual drivers. Points of crossover around 900 and 3100 Hz. The 12MU really handles an important part of the lower treble response - and it does it well. Overall a very smooth combined response.

To the right we see what happens when we invert 12MU polarity. Deep suck-outs are produced around points of crossover telling overall phase integration performs well. Initially I had the 18WU and 12MU in the same plane, but pulling back the 12MU some 20 mm gave the above result. To the right the MmT step response showing negative polarity of tweeter and 18WU and positive polarity of 12MU.

Left: Un-smoothed response of final system including port contribution. Don't put too much into what's below 200 Hz as this is made merging far-field and near-field response and it can look quite different depending on data manipulation. What cannot be seen is the overall powerful bass response from this speaker and the bass punch due to the 22W being in a closed cabinet.
What can also not be seen is the low-level detail this speaker is capable of due to the small 12MU midrange driver. Getting good dispersion in upper-mid/lower treble is one element in low-level detail along with low-loss drivers.
Right: Final system impedance (red) and electrical phase (black). My 80 wpc Jungson has no trouble running this speaker to thunderous levels.

Two graphs on horizontal dispersion. Left @ 0, 10, 20 and 30 deg. Right: Here 40 and 50 deg included.
This ensures a very consistent power response regardless of listening angle.

Kit can be bought with/without drivers - or some of the drivers.
Above the level 2 kit. Level 1 has Amber-Z caps for tweeter.

All kit and component prices may be subject to change and are always to be confirmed by Jantzen Audio Denmark.

Crossover layout for 18WU/12MU/3004 section.
C1041 has been replaced by a single capacitor.
The board here is approx. 308 x 290 mm (width x height as seen above).
The exact width of all the caps at bottom is 306 mm.
Make sure your board can fit into the crossover compartment before doing the layout.

Crossover layout for 26W/22W section.
This section will be placed behind 26W driver on rear panel.
I cut off some of the length to the left before mounting.
All electrolytics are now replaced by Jantzen Audio MKT-Z caps.
These are bigger than the electrolytics, but there is plenty of space on the board, so keep the layout seen below.