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Newtronics Temperance

Transmission Line Loudspeakers

[Italian version]

Product: Temperance Loudspeakers
Thanks to: Newtronics GmbH - Germany
Cost: 7800 $/Euro per pair
Reviewer: Steve Davey - TNT UK
Reviewed: December, 2002

[Temperance Loudspeakers]

All that is needed to produce a sound wave is an oscillating diaphragm. And the choice of Hi-Fi loudspeakers available to achieve this function is endless: The almost universal entry point is the two-way ported or sealed box design. Prices range from less than one hundred Euros to over one thousand - and thatís for a relatively simple piece of hardware.
Now admittedly designing the perfect two-way is recognised as being more of an art than a science, requiring many hours of an expensive expert designer, and once the design is optimised, the production of the loudspeakers is not readily automated. The relatively low sales volumes do not warrant the tooling of a robotic production line as might be found in say the car industry. Thus loudspeaker assembly remains more of a craft than many modern day production activities and so prices are largely determined by construction complexity and component quality.

Beyond the "simple" two-way designs one starts to encounter designs with more drivers and more complex electronic crossovers, or maybe only one driver as in horn designs with complex cabinet construction to craft the horn. In both cases we are entering the realm of lower and lower sales volumes and more and more complex production, leading of course to higher costs and thus prices.
Moving away from the traditional (usually circular) cone drivers (made from materials ranging from paper to plastics to wood) leads to ever more expensive designs such as electrostatics or hybrid designs incorporating ribbons, horns, multiple drivers, active/passive coupling and multiple cabinet chambers and sub-assemblies.
Once one embarks on the upgrade path the price of components spirals upwards very quickly and you might end up listening to square black boxes that cost more than the average family car or in some cases more than country cottage in some European countries (not in the UK though with its insane property market)

All this is to say that you can get some very respectable sound indeed from loudspeakers costing less than 500 euros so why spend more than ten times that sum? Well as I have discovered in the past few months if you are able to consider spending this sort of money on an upgrade the rewards are not inconsiderable. And that brings me to the Newtronics top of the range passive loudspeaker, the Temperance.

What you get for your money

For anyone who might splash out said asking price for this pair of loudspeakers, unpacking them should not be a disappointing experience. They are well-finished sleek designs, housing an imposing five drivers per side and weighing in at 30 Kg, so when the packing advises that two people are needed to lift these speakers into position this is good advice.
The Temperance are transmission line designs. Now TL theory is not something I would claim to understand well. However, I have an intuitive abhorrence of resonance enhancement to give a loudspeaker more "kick" or apparent bass as they can sound "single-noted". Yes you can pick out the bass rhythm but what about the melody.
What a transmission line gives in my experience is a much smoother and more realistic bass quality. The internal folding of the transmission line also serves to brace the cabinets and as common for this type of design the Temperance sound "dead" when tapped.
Constructed of fibre board, the sides are veneered while the beautifully formed front baffle and backs are finished in satin black. These latter pieces over-hang the side, top and bottom panels by about 1 mm, rather than being perfectly flush which I think would have given an even better presentation.
These are big units standing 1.15 m tall but the a narrow baffle (measuring 22 cm wide) and ability to be sited near a wall means that they are not intrusive even in a modest listening room. Unusually for Hi-Fi kit in my experience, these units attracted complimentary comments from everyone who has visited us. Audiophiles and the tone-deaf alike - and thatís even without any music playing.

The front baffle is sloped backwards, which is not uncommon these days to achieve better time alignment of the drivers. The speakers also come with four spikes which also allow for additional tilting if required; I did not bother with this and simply made sure all four where well seated on the floor to make for a stable platform.

So external appearances suggest a multi-way design albeit incorporating a transmission line construction. But the crossover design and driver selection reveals a departure from most multi-driver implementations.
There are five drive units all manufactured by Danish Sound Technologies and taken from their Vifa range; a tweeter, midrange driver and three units for low frequencies. In fact the low frequency crossover frequency is a very low 120 Hz - more like a sub-woofer driving a transmission line than a traditional three-way arrangement. The tweeter cuts in at 3 kHz and this too is rather lower than found in most three way designs.
Inspection of the crossover, situated near the bottom of the speaker in a separate back chamber, reveals a very simple circuit, containing two inductors, a large one for the 120 Hz low pass to the bass units and another for the 3kHz low pass to the midrange driver. The tweeter high pass filter consists of two capacitors. The Temperance thus utilises first order 6 dB per octave filters and is configured more like a two-way design with integral sub-woofer.

Benefits and Problems of First Order Filters

Three way designs more usually utilise higher-order filtering and lift the high frequency cut-off an octave or more higher than 3 kHz were the ear is sensitive and thus emphasises crossover distortion arising from acoustic incoherence. This arises from phase and temporal misalignment of the drivers at frequencies either side of the crossover frequency.
However, Newtronics have used first order filters to frequency-separate the tweeter and mid range driver, which theoretically provides coherence, a property that has been argued as desirable for some time but requiring drivers able to tolerate the slow roll-off of the filters.

With first order filters the signal is attenuated at only 6 dB per octave. So for a 3 kHz crossover the sound level originating from each driver will have been attenuated by 3dB but sum to provide the prefiltered sound level because of the desirable phase relationship imparted by the filters. Theoretically, either side of the crossover frequency, sound from the two drivers sum to its pre-filtered level for a listener positioned on the axis of the speaker.
However, both drivers will be producing audible output at least two, probably three and possibly more octaves either side of the crossover frequency. As an example the tweeter output at 750 Hz will be attenuated by 15 dB; and whilst the electrical power provided to the tweeter at this frequency will have been attenuated by a factor of 24, due to the earís near-logarithmic frequency response it will only seem about about one third of the volume.
So if the tweeter is not able to handle a signal at 750 Hz, then not only is it possible that it may be damaged but that the distorted sound is likely to be heard despite the dominance of the mid-range unit. Similar considerations apply to the high frequencies being produced by the midrange unit at 12 kHz.

The Newtronics Solution

[Vifa Tweeter]

The high frequencies are handled by the Vifa 1" dual concentric dome tweeter, which has a rather pointed centre plug designed to improve off-axis response. Its frequency range is cited as 1.5 to 40 kHz and thus falls into the category of super tweeter capable of reproducing those frequencies beyond human hearing (say 20kHz) but claimed by some to influence the perception of sound. As my amplifiers are band limited at about 20 kHz I have no idea if this works or not.
The published frequency response for the driver indicates that its output begins to tail off at 800 Hz and is only 10 dB down at 300 Hz. Hence its ability to cope with a first-order high pass frequency of 3 kHz.

There is a similar situation with the three Vifa 6" drivers that handle the low frequencies. These are capable of producing frequencies well in excess of 2kHz so a first order low-pass at 120 Hz is very benign indeed.

[Vifa Midrange Unit]

But it is the mid-range driver, or what I think of as the main driver, that looks rather special. This Vifa unit features a wood-fibre cone and dust cap which is billed as being "phase-integrated". The unit's published frequency response, measured on-axis, displays a relatively smooth linear trace from 50 Hz up to around 7 kHz and beyond.
Whilst not a full-range driver it is capable of handling high frequencies up to 10 kHz and at 12 kHz the on-axis response is attenuated by 20 dB relative to the output at 3 kHz. Off-axis the response is not so impressive as it falls off rather more rapidly. But on axis the driver would appear capable of handling the first order filtering up to almost 12 kHz.

The Complete Package

The Newtronics web site provides a frequency response curve for the Temperance which appears quite flat, albeit with broad peaks around 50 Hz and 5 kHz, with the speaker being specified as +/- 1dB between 25 Hz and 20 kHz. So all in all one might expect a natural sound from these units with no obvious upper frequency lift or resonance-induced bass.

Newtronics say little about their design philosophy but my assessment is that they treat phase coherence as paramount and the use of first order filters and a sloping baffle to time align the drivers, mated to the transmission line makes for an intriguing proposition.
The speakers are rated at being capable of handling short term power levels of 280 W, and whilst transmission lines are not the most sensitive of designs, should be capable of producing very loud music.
But a powerful amplifier is likely to be required when considering the nominal impedance of 4 ohms, the transmission line and the large inductor needed for the 120 Hz low pass filter to the bass units. This leads me to comment on the fact that bi-wiring is not offered on the speaker. There are two bulky gold plated 4mm sockets/binding posts per loudspeaker. Whilst bi-wiring can provide sonic benefits, bi-amping really can improve things, admittedly at the expensive of an additional amplifier.
Whilst I can report that my Naim amplifiers were able to drive these speakers with no apparent problems, it would have been interesting to have tried bi-amping because I suspect the 120 Hz inductor is not a benign influence unless you happen to have a Krell lying around.

So the Temperance is a loudspeaker based on the transmission line, having coherent crossovers, somewhat specialist mid-range driver and tweeter, whilst equipped with no-less than 3 bass units. Having man-handled them into position and hooked them up, I fired them up with great anticipation, but with a warning from the dealer that supplied them that, "they would take 100hrs, at least, to burn-in".

What Sound do they sound like?

Most of my listening was done using an Orbe/OL250/AT33 front end but I also had a number of other units, including my Sony DVD hooked up from time to time. Straight out of the box, these speakers do not impress so with the warning "they take at least 100hrs to burn in" in mind, I put on a CD, turned up the volume and - hey these speakers do play loud - I walked away closing the door behind me.
Five hours later I sat down and listened again and thankfully things were improving. The sound continued to improve for many weeks thereafter and whilst I didnít time how long it took (probably not 100 hrs) I began to appreciate what a speaker in this price range can do.

Yes these beasts play loud - really loud - capable of recreating the ear splitting, chest thudding wall of sound of an AC/DC concert in my living room.
In fact the Temperance need to be played at realistic volumes to show their best. If you want loudspeakers to create background ambiance then donít splash out on serious kit like this. If on the other hand, you sit down and listen to music as you would hear it live - that is at levels which make it impossible to have a conversation with someone else in the room, then the Temperance begin to show their qualities.

The sound is beautifully integrated with voices, guitars, drums, piano all sounding like single distinct instruments with their own timbre and sonic character; rock solid in a sound stage that extends well beyond the speakers. The presentation is forward of the plane of the íspeakers with vocals especially giving that in-the-room effect. You are in the front row not at the back of the auditorium.

The presentation is very natural with no apparent emphasis of highs to "improve" detail or speed nor enhanced bass to give the illusion of power. What is produced is tonally constant across the octaves so that if the mix is busy the sound is full, yet if there is space around the instruments then this is tangible.
No record sounded harsh with the Temperance - they are very smooth sounding once burnt in. This may be an issue for those used to a lively in-your-face presentation.
But running through my "killer" records revealed that all that I hope to hear was there often with greater clarity than I had heard before. What these íspeakers seem to do is draw you into the performance rather then present it to you. And on some material, for example The Chemical Brothers "Out of Control" the impact can be startling. Yet on acoustic music all the subtleties and emotion are conveyed.

One of the advantages of having a product over a (very) long period is that you get to play a lot of music, not just the "killer" albums, and in so doing a high quality product like the Temperance can be very revealing.
Although I had listened to U2ís "I Still Havenít Found What Iím Looking For" on Rattle and Hum many times, I hadnít before really picked out the interplay of Bonoís vocals and the two soloists. These soar in and out of the performance, playing off one another, eclipsing Bono in the second half of the song. Everything else in the mix is still there, its just that being able to hear better the nuance of the performances sets that performance apart from any other version of the song.

Conclusion

Living with the Temperance for a number of months has been in many ways a privilege. At this price level there are only a few percentage of music lovers that could contemplate spending so much money on a pair of loudspeakers. Having said that there is a healthy market out there for such products and there is plenty of choice.
And that is the problem. I have been wondering how a potential buyer would go about choosing an expensive loudspeaker? For most people they would need to look like an expensive piece of equipment and probably for many unconventional. Whilst the Temperance look great they do appear rather conventional but then again that might appeal to many, as evidenced by the reaction of my visitors.
One would hope that sound quality would be the most important selection criterion and at this price point personal taste is going to play a big role, hence an audition is essential. The Temperance clearly deserve an audition but they must be burnt-in.
Probably better suited to high power amplifiers, the Temperance reward the listener with a very natural presentation, that reproduces fine detail, tangible imaging and capable of being played loud!

© Copyright 2002 Steve Davey - http://www.tnt-audio.com

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