Ellam FLEX 3W
Copyright 2020 Troels Gravesen

Discontinued from Jantzen Audio. Buy components locally.


22W/4851T00, 15W/8530-K00, D3004/660000 drivers.
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Download specs here:   22W/4851T00 15W/8530-K00, D3004/660000


Have you already built the Ellam FLEX 2-way and want to move on with the electronic crossover version, the path is simple. Build the bass cabs and buy the bass drivers. I recommend the 4 ohms version although the 8 ohms bass drivers are fully acceptable. Should you also want to try the passive version, buy the 4 ohms bass drivers as only a crossover for this version will de developed.
What kind of electronic crossover you should buy is fully up to you. I use the dbx 223xs with XLR connections. Make sure it's a 24 dB LR filter with adjustable point of crossover and level regulation. If you use a digital crossover, any setting should be available. Try it out and please report back and I may post your findings.

With the electronic crossover I found the most balanced sound from setting the point of crossover between 220 Hz and 280 Hz. In principle the Ellam FLEX 2-way is a full range speaker and you could use the bass modules as dedicated subwoofers up to e.g. 60-80 Hz. However, going below 200 Hz, the Ellam FLEX starts sounding thin and lack the power in the 100-200 Hz range larger speakers can manage. There's an awful lot of energy in 100-200 Hz range and from my preferred 240 Hz point of crossover we have a full-blown 3-way speaker with lots of dynamics and low-end fullness.

You cannot use any other drivers than those specified or you need a new crossover, and I can't help. Please read here: (e.g. you cannot use the 8 Ohm version of the bass driver. The bass driver determines the overall system sensitivity and any change here, changes all parametres.)

3-way speaker.
System sensitivity: 88 dB/2.8V, 1 meter.
Impedance: 4 Ohms, minimum 3 Ohms @ 150 Hz.
Crossover: Low-order LR2 filter, 400 Hz and 2500 Hz.
Power requirement: 25+ wpc.
Power handling: 100 watts, but please also read this:, and remember any burned driver is a misused driver.

The Sound

I'm really, really pleased with the sound these speakers and I'm happy to discontinue some of the former Ellam 2-ways and the Jazzman 3-way. These new speakers are simply better and throw a solid sound stage from a significant smaller footprint compared to the Jenzen speakers. Listening to Stravinskij (Sacre du Printemps) over the Ellam F3Ws here from my desk next to the door into our living room, I easily forget it's not the Jenzen ATSs running. Level of transparency is everything I hoped for and I run to say the Grail phono stage and Glowmaster KT88 power amp plays a role here. Only pleased the Ellam F3W delivers the goodies when asked to.  
I'm almost sorry to say the passive version performs better than the active as so many love electronic crossovers. There may be several reasons for this. First of all LR2 sound different from LR4. I always found LR4 to have a certain slightly flat presence sound. The LR4 filter is superior in terms of even power response but lacks the soundstage depth of the LR2. How an electronic LR2 would sound I can't tell because I don't have one. I guess they would be quite similar.
Bi-amping the Ellam FLEX 3W takes the Ellam F3W speaker to another level. The GlowMaster obviously runs the mid-tweeter and a new 200 wpc digital amp runs the bass drivers.

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Ellam FLEX 3W passive CROSSOVER, 4 ohms bass driver
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A good front panel layout allows a simple crossover.
Basic simulation came very close to this, only L2041 and R1011 (as always) had to be adjusted by ear.
L2021 is a high-ohmic coil, DCR = 1.2 ohm. C2021 is made from 3 x 22 uF in parallel. The C-coil for bass (L311) allows extremely low DCR.
R2031 and R1011 are the resistors for tweaking midrange and tweeter level. I had a hard time deciding between 1R8 and 2R2 for R2031 but ended up with 1R8.
For R1011 3R3 was soon in place. 2R2 renders a rather flat response but makes a too aggressive treble level. 2R7 if you like lots of detail. 3R3 if you want a balanced presentation of basic notes and overtones.

Points of crossover: 400 and 2500 Hz, 12 dB LR.

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Left: Click image to view large.
Right: Possible shapes of rear chamber for placing mid-tweeter crossover.
I made slots in the rear panel to allow proper ventilation from port.

If you want to make a bass reflex cabinet, go for 40 litre and a port tuning of 35 Hz.
Add minimum 2 braces to the cabinet. Not further details from here but keep frnt panel design.
Port = 68 x 120 mm length. And it can be front or rear.

SketchUp file available here.

Go to cabinet construction page

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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 anything 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 way 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.



Left: SPL of @ 0.25 meter, normalised for 2.8V/1 meter from 22W/4851T00 (both drivers) on a 30 x 100 cm baffle, mounted 40 cm from top. Right: Same for 8 ohms version, 22W/8851T00. All merged with near-field response at 200 Hz. Drivers mounted in 33 litre closed cabinet. This to start getting an idea of where the system sensitivity will end for the 3-way passive crossover. My intention is to only make a passive crossover for the 4 ohms bass driver as we here seem to be able to get something in the range of 89-90 dB system sensitivity. If I calibrate my measuring system against the ScanSpeak R2604/832000 tweeter I would reduce my readings with something like 0.50-0.75 dB, thus I think can safely target the system sensitivity at 88 dB/2.8V/1 meter for the 4 ohms bass driver system.

Final system measurements for 22W/4851T00 system.

Left: SPL @ 1 meter, 2.8 volts, merged with bass nearfield response at 250 Hz. System sensitivity = 88 dB/2.8V/1 meter.
Right: System impedance. Minimum = 3 ohms at 150 Hz. For the newbee this means a 4 ohms speaker and your solid state amp will have no trouble driving them. For valve lovers, you need minimum 50 watts push-pull, preferably 80-100 watt, to fully exploit this speaker.
Low-wattage SET amps are not recommended.

The readings above is to demonstrate points of crossover.
Left: When measured with reverse polarity the response is not merged at 250 Hz as this would look misleading.Bass-mid: 400 Hz.
Right: Mid-tweeter: Point of crossover = 2.5 kHz.

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All technical question at:

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Since introduction, Alumen-Z and MKT Z-caps have found their way into the crossover.



Click image to view large.

Click images to view large.

Place the bass crossover on the rear panel behind the bass driver.

Right: Stuff the mid cabinet vent with acoustilux as seen on photo to make an aperiodic tuning.
Cut a piece 135 x 150 mm of 30 mm acoustilux, roll it and stuff the vent. (135 mm = length of vent).
I had some grey acoustilux as seen on photo. It is not grey felt.

R3004/662000 version
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Download R3004/662000 data file.

6620 Crossover

Crossover Kit (same as 6600 version)


All technical question at: