ScanSpeak Revelator-3WC
Copyright 2023 © Troels Gravesen

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The intro to this construction could be a copy-paste of the Revelator-851, as it features exactly the same drivers, but quite a few have found the Rev-851 cabinet a bit too complicated and asked for a standard 3-way classic in a simple rectangular box, so here it is.
Cabinet is made as simple as possible - and with a slotted port - and we save money. Having a different cabinet shape calls for a new crossover, hence not the same as Rev-851.

I have made a lot of these 3-way classics - and for good reason. Easy to construct is an important issue as a lot of people do not have sophisticated workshops, rather hand tools and basic workshop facilities. Does this mean we can only build lesser quality speakers? Not at all! A classic 3-way may prove just as good as any fancy looking speaker with high-gloss lacquer, etc. In fact, what we can do that commercial manufacturers mostly cannot, is using premium drivers and premium crossover components. The latter something totally absent in commercial speakers, unless we're taking 10-20+ k€/pair. We see seriously expensive speakers in e.g. 5k€ range with el-cheapo Bennic capacitors. Remember, most commercial speakers are ~10 times the production cost. And so it must be to make a viable business. As DIY'ers we can skip marketing, packing, transport, distributor profit, dealer profit, etc.

With the Revelator drivers used here we're into high-end and with high-quality baked coils, Superior-Z and Alumen-Z capacitors we're into super-high-end. A speaker is never going to sound better than what crossover components allow to pass to the drivers and especially capacitors are a key ingredient in high-quality sound reproduction.

Also in mind here is costs, thus the slot port and simpler crossover topology without compromising sound compared to the Revelator-851.


Going through my current selection of records I found a seriously potent bass, stellar clear midrange and seamless integration of midrange and treble. No sibilance unless recording is sibilant. This is in no way inferior to the Revelator-851. Had I been able to make this classic 3-way some 30 years ago, this website might not have existed at all.
My 32 wpc EAR-861 can play this speaker to alarmingly loud levels from its 8 Ohm tabs.

3-driver speaker.
Dimensions: 28 x 36 x 61 cm, WxDxH.
System sensitivity: 89 dB/2.8V/1 meter.
Impedance: 4-8 Ohms.
Power requirement: 30+ watts/channel.

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Download specs here:  D3004/660000     15M/8631G00     22W/4851T00


Crossover is a simple LR2 filter with inverted polarity of midrange driver.


Cabinets were made from 20 mm Baltic birch. You can use 19-22 mm MDF - or 18 mm as seems available in some places, but add bitumen pads to your order if 18 mm is used.
In any circumstance, keep front panel dimensions and drivers' placement.
And yes, yes, YES! You can place the port to the front. Who on earth made the claim that rear ports are bad?? Ports usually leak some midrange - and not the good part!

The speakers should be placed on stands to have the tweeter at ear height.

Workshop pics

The cavity behind the midrange cabinet is added felt on all sides.

The pictures should tell the story of felt damping.

Making the tweeter panel.
I add lacquer to the tweeter panel and upper edge of front panel before gluing.

Making the front panel. Remember chamfering the midrange driver hole.
The vertical strips have no structural function, just decor. Same for tweeter panel, can be made from just inserting piece of BB and adding veneer or filler/paint.

Lacquer work finished.

Left: Fold two pieces of 25 x 50 cm acoustilux and place in cavity behind mid cabinet.
Right: Cut 2 pcs of 25 x 50 cm acoustilux and place on rear panel and port panel.

Cut one piece of 25 x 75 cm acoustilux and place on rear panel and side panels around bass section.
Place 60 grams of wool in mid-tweeter cabinet.

Workshop setup during crossover fine-tuning.
I prefer the mid/tweeter towards the center.
I don't fancy this artificial wide soundstage from placing speakers wide apart with mid-tweeter in outer position.

Crossover placed on rear panel.
Fasten with screws - never glue!


A few comments on MEASUREMENTS before you start interpreting 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, although dispersion characteristics play a vital role here. A two-way 7+1 and a three-way 7+4+1 may display similar horizontal dispersion, yet sound very different. 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 we 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 speaker, because speaker cones made from polypropylene, aluminum, Kevlar, paper, glass fiber, carbon fiber, magnesium, ceramics or even diamonds all have their way of adding spices to the stew. Nor do measurements tell what impact the quality of the crossover components add to the sound, from state of the art components to the cheapest of coils and caps, they all measure the same if values are correct, yet sound very different.


SPL measured at 1 meter distance.
System sensitivity around 88-89 dB/2.8V/1m.


Horizontal dispersion at 0, 10, 20 and 30 deg. off-axis.


Final system impedance, minimum 3.7 Ohm @ 113 Hz.




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

Kits can always be bought with/without drivers, or some of the drivers.


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Check this out before start making crossovers:

Mid-tweeter layout.

The money has been spent where it matters the most: Capacitors. Superior-Z for the midrange and Alumen-Z pure foil capacitor for the tweeter. This is higher high-end!

Wiring of tweeter and midrange.




Bass layout.


Speaker wiring.
Notice midrange is connected with inverted polarity!