Trans-Fi Audio

Home of the Terminator Tonearm


April 2022:

Major update to system. Now gone active! Wasn't a sudden decision, but gradually built up to it (see Speaker Blog here )

Still partnered with a pair of reversed Dayton  UM18 woofers (updated from 15"). Reversing the woofers adds directivity and reduces room modes.

Integration with the subs is simple. Problem using passive speakers is no control of the bass roll-off. The Focal Shape 50's have high pass filter switches. I find using the 65 hz cut-off with UM18's  gives best result.

Went though a few stages to get to where I am now. The   18" AE (Acoustic Elegance) Dipole woofers were  replaced by the Dayton 15" 390s a few years back, and now UM18's. These have much heavier fiber-glass cones and a more powerful motor. Arranged in series, they give more depth, take more watts and yield higher SPL's without complaining. They generally take more abuse and dont bottom out as easily as the AE's. I found I get REAL deep bass (20hz) with heavier inefficient woofers vs lighter more efficient designs.

In this F.A.S.T. configuration (FullRange Assisted Subwoofer Technology) or WAW (Woofer Assisted Wideband) there is no crossover to sap efficiency and resolution. The Shapes having built in amps now connect directly to the Topping D90LE via XLR connectors  & handles from 65Hz up to 20k.

I have found the UM18's need no eq to compensate for for bass baffle losses.

Operating now from 20-60Hz, they don't add much in terms of fidelity. The more like rumble when required!

The disadvantage  of using inefficient woofers is they need a lot of power, but watts come cheap  with the Behringer NX6000D's. The built in Digital Signal Processor makes setting the crossover point a breeze & also iron out room modes.


A pair of Behringer NX6000D's power the 18" woofers. This is primarily  PA concert venue Class D full range amp. Not sure what it sounds like full range, but  from 20 - 100Hz & it sounds great! Delivers effortless distortion free power, control & resolution..........everything you want in a sub amp.

The DSP section just plugs into a laptop via USB & uses software available from the Behringer site. All relevant parameters can be adjusted in real time from your listening position. The crossover page allows seamless integration with the full range unit. There is a choice of 4 variable slopes, plus crossover point & gain. There is also an 8 filter Parametric EQ page to set compensation for room modes & baffle deficiencies.


The Topping D90LE + A90 Discrete preamp the hub of the system. This is now fed a Tidal stream using the A11 Tablet via an iFi Zen Stream. The signal from the streamer is passing through a Digital to Digital Converter (DDC) an Audio-GD Di-20 which de-jitters & cleans everything up.  I can connect my TV Box, Phono Stage & PC via the DAC  digital inputs. 




This system is very personal & not for everyone. I find myself usually getting bored quickly, so this is designed to be upfront, very detailed and dynamic......however, not fatiguing ......even the wife will sit & listen for hours, but would run out of the room with the Bastanis! 

I have discovered throughout my hi-fi life the system would dictate what I listened to. I gradually abandoned my rock roots and steered  towards gentler acoustic vocal material simply because the system would produce this better. I started to realise this when I abandoned full range drivers! I have not found a FR driver that rocks!

In addition, going back to boxes....especially the 3-way KEF center channels..... I started to hear slam and bass texture in the 80-300hz range that was missing with Open Baffle. This led me on a quest to find the best speakers with this trait in the upper bass/lower mid region. Had to be active, and effectively sealed, or using passive bass radiators rather than bass ports which I felt lacked definition. This makes sense because once the sound wave exits the box via the port, you have no control of the moving air.  Slam from bass notes are followed by a wizards sleeve of low frequency bloom that veils the midrange and slowly fades into a plume of lingering sonic smoke. I guess some manufacturers may try to shape & tune the port in such a way to restrict the air flow and get rid of this smoke, but all of the dozen or so speakers I tried had this effect in varying degrees. 

I luckily discovered the Focal Shapes Studio Monitors which are effectively sealed. Bass only exits via a pair of tuned passive radiators (and of course the driver itself) damped by the trapped internal air which acts like a spring. Bass notes are emitted with brutal impact, and then stopped dead when the note fuss, no bloom, no plume. Maybe not for everyone that wants a certain cuddly warmth associated with their bass!

Being active, the crossovers are efficiently optimised at line level so not sapping any dynamics. Also a high pass filter is incorporated allowing fine adjustment of the crossover with the UM18 subs. This is vital to avoid bloat and room modes. Another advantage I noticed with the active speakers I tested is they go loud, but maintain composure never showing any signs of stress.

The woofers driven by the Behringers integrate seamlessly with the Focals aided by the built in HPF. They go floor-shakingly deep when the signal is present but there is no boom from room resonances (30 & 50hz in my room) such is the control from the PEQ. For serious bass I believe the woofer needs to be actively driven with  PEQ. Control of the room modes is a necessity.

I can play a wide range of music on this system from softer acoustic jazz material to pumped up Level 42 playing at realistic levels. Modern electronic music, which I was never too keen on, makes sense now that I can hear/feel that bottom octave, and appreciate the upper bass slam & texture the composers spent so long to engineer.  Kraftwerk, Depeche mode never sounded so good not to mention the more modern Monolink and London Grammar. The system delivers it all in a musical, fatigue-free fashion and keeps me interested!