Reviews
"The Super Tweeter can extend the bandwidth of your
speaker with astonishing results."
"If it's of the performance envelope-pushing persuasion,
the Townshend Super Tweeters will undoubtedly take it,
and you, to the next level."
Hi Fi Choice November 2002.
"I still have my Maximum supertweeters, thank goodness,
but I have tried living with them switched off and, believe me, it felt
like masochism"
Keith Howard. Hi Fi News and Record Review March 2003.
Positive Feedback review Click to view
Specifications
Frequency response. 20Khz to 70kHz. -3dB 12kHz to 90kHz.
-6dB
Sensitivity adjustable to suit speakers with sensitivity from 80dB to
110dB.
Impedance 6R, 20Khz. 30R, 100kHz.
Power rating. 350W+. Music (heavy rock)
Dimensions. 50mm (W), 30mm (H), 100mm (D).
Case. Stainless Steel Mirror or Titanium.
The Maximum Supertweeter is now offered in three finishes.
You may choose between Mirror Stainless steel (by far the most popular) Titanium and just introduced classic “Crackle” black.
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FAQ
-What does the Maximum do?
It extends the response of your main speakers out to ultrasonic frequencies, and does this much more effectively than dome ‘supertweeters’ which have relatively poorly extended responses and suffer breakup resonances.
We have measured the Maximum’s output up to 90kHz and it is virtually flat from 40kHz. Probably its response extends out to even higher frequencies but we haven’t the microphone to measure it! So the Maximum can reproduce anything captured on SACD or on DVD-A at up to 192kHz sampling rate. Typical dome supertweeters struggle to reach 50kHz and also have uneven response because of resonances within the dome. The Maximum avoids the frequency and time domain problems associated with resonances because it uses a ribbon diaphragm – not an etched plastic-backed leaf like ersatz ‘ribbons’ but a proper rippled aluminium ribbon.
The ribbon is also an advantage in respect of sound dispersion. One-inch dome tweeters become highly directional at ultrasonic frequencies because the diaphragm is large relative to the radiated wavelength (1.7cm at 20kHz, 0.7cm at 50kHz). Because of its ribbon is narrower, the Maximum disperses its output much more widely in the horizontal plane, so its effect can be heard over a wider listening area.
-Why do frequencies above 20kHz matter?
Most of us, even when we are young, are unable to hear sine waves at
frequencies over 20kHz, although there are some exceptions. As we become
older, even if we’ve looked after our hearing, it is normal for
our ears’ sensitivity to extreme high frequencies to reduce so
that by age 50 you may well struggle to hear sine waves above 16kHz
or so.
In the past this has been taken to mean that there is no point in reproducing frequencies above about 20kHz, even though there is well documented evidence that many musical instruments produce significant output at higher frequencies (see, for example, James Boyk’s spectral analyses at www.cco.caltech.edu/~boyk/spectra/spectra.htm . But some people in the audio industry have always espoused a wider working bandwidth, and with the advent of high-rate digital recording and reproduction equipment, operating at sampling frequencies of 96kHz and above, it has become obvious to many audiophiles that a 20kHz limit compromises sound quality. That’s why we now have SACD and DVD-A – to extend the high frequency bandwidth over that embodied in Compact Disc.
In addition to the copious anecdotal evidence that extending bandwidth to (so-called) ultrasonic frequencies improves sound quality, there is also scientific evidence that we are able to perceive frequencies above 20kHz. It has been shown, for instance, that if a speech signal is modulated to ultrasonic frequencies and delivered via skin contact to the head that we not only sense the vibrations as sound but are able to understand what is being said! Studies using electroencephalogram (EEG) techniques have also shown that brain activity changes when a listener is exposed to reproduced sound with and without ultrasonic content.
-What difference do you hear with the Maximum in a system?
The sound stage opens out and the music becomes crisper but at the same
time airier and more natural. Essentially, the result is just much
more realistic. You needn’t worry, by the way, that the sound
will become more tiring over extended listening. Provided that the
Maximum’s output level is set appropriately for your main speakers’ sensitivity,
you’ll find the opposite happens. Because reproduced music now
sounds more natural, it is easier to listen to for long periods.
What you won’t hear is much obvious output from the Maximum itself. Because of the frequency range over which it operates, if you play it alone you will hear very little sound coming from it. But if you switch the Maximum on and off while the main speakers are playing you will hear clear differences of the type described. It is one of the intriguing features of reproducing ultrasonic frequencies that the presence of lower frequencies is needed to potentiate their effect.
-Why does the Maximum make a difference with CD sources?
A good question. As the maximum frequency that can be recorded on CD
is 22.05kHz, you might suppose that the Maximum could make no difference
to CD sound quality. But it does – a big difference, as many
of our customers will attest. Why does this happen? We can’t
be certain but we can think of two possibilities. The first is that
the ear ‘locks on’ to the more coherent, resonance-free
output of the Maximum, even though it is at lower amplitude than that
of the main tweeters. Alternatively, it may be that by pushing one
of the low-pass filters in the system out to a higher frequency, it
improves the system’s overall impulse response. (As you may know,
there has been concern expressed about the impulse response of the
steep low-pass filters used in digital audio since the early years
of CD.)
-Does the Maximum have an adjustable crossover?
No, the Maximum has no low-pass filter section – the feed to your
main speakers is not changed in any way – and a fixed high-pass
filter that rolls the response off at 12dB per octave below 40kHz. We
find this arrangement works well with a wide variety of speakers. But
the Maximum does have adjustable sensitivity via an eight-position rotary
control on its back panel, so that its output level can be correctly
matched. With direct radiating speakers of typical sensitivity, positions
3 or 4 on the sensitivity control are usually sufficient. But if your
speakers are of unusually high sensitivity (eg horns) the Maximum has
sufficient inherent sensitivity at its higher settings to deliver the
required output level.
-Is it easy for the amplifier to drive?
Yes, very easy. Even at its highest sensitivity setting the Maximum has
a benign 8 ohm, non-reactive input impedance over its working range,
with a rising impedance at lower frequencies. At lower sensitivity
settings the Maximum’s impedance increases, so it becomes an
even easier load for the amplifier.
