Satori MR16TX-8 6.5" TeXtreme midrange review

  What and why am I testing?

• 1.2" tweeter TW29TXN (4 and 8 Ohm) (review)
• 5" midwoofer MW13TX (4 and 8 Ohm)
• 6" midwoofer MW16TX (4 and 8 Ohm) (review)
• 7.5" midwoofer MW19TX (4 and 8 Ohm) (review)
• 9.5" woofer WO24TX (4 and 8 Ohm)

As you can see, to complete the line only “true” midrange speaker was missing, although many people have successfully used 5" Satori MW13TX and 6" MW16TX midwoofers as midrange drivers before, as their characteristics were perfectly suitable for this task. From personal experience, I will say that I never had any complaints about their performance in the midrange. Nevertheless, the company decided to take the matter to its logical conclusion and now there is an opportunity to build loudspeakers, from bottom to top, on speakers with TeXtreme diaphragms highly specialized for their frequency range.

Today we're taking an in-depth look at the Satori MR16TX-8 6” midrange as part of a series of reviews initiated by Sinar Baja Electric.

I would like to thank Mark Thomsen (Marketing and International Sales Manager at Sinard Baja Electric) and Frank Nielsen (CEO & Owner at Danesian Audio ApS) for kindly providing me with samples of Satori MR16TX-8 speakers for testing and helping me solve logistical problems.

Here you can learn about the history of the SB Acoustics and Satori brands, as well as one of the world's largest speaker drivers manufacturer - Sinar Baja Electric (www.sinarbajaelectric.com).

  The datasheet

The whole set of parameters, as well as all design features allow to refer MR16TX-8 to the top class speaker

It's worth noting:

• Low inductance of the 8-Ohm voice coil - only 0.11 mH
• High mechanical quality factor Qm=6.47 and extremely low mechanical losses Rms=0.35 kg/sec. In my entire database I could not find a single midrange or midwoofer with lower mechanical losses!

  The package and construction

The MR16TX-8 comes in a sturdy package made of glossy corrugated cardboard. Inside, the speaker is protected by cardboard inserts with shaped cutouts.

Visually, the MR16TX-8 midrange is absolutely identical to the MW16TX-4 midwoofer, except for two things. The first one is that in MW16TX-4 the voice coil is strongly protruding from the magnetic gap and, therefore, is much more visible. It is quite natural, as the height of its voice coil is 17 mm against 10.7 mm of MR16TX-8. Second, the midrange has an inverted, i.e. concave surround.

The production quality is exemplary, there is nothing to complain about. Perfectly fitted parts, complete absence of any cosmetic defects, no burrs, distortions, chips and traces of glue. The label is perfectly aligned.

The acoustically very transparent basket is made of aluminum alloy and coated with black micro-textured powder coating. The flange thickness is 7.5 mm, the spokes are very strong. The magnetic system is equipped with a rubber ring with shaped elements that visually continue the spokes of the basket. It has no serious functionality, but it nicely complements the design of the basket. A foam gasket is glued to the back of the flange.

All elements of the magnetic system are not made by simple casting or stamping, but with subsequent turning, as evidenced by the cutter marks on the outer surfaces. This is one of the conditions for narrowing manufacturing tolerances and improving the consistancy of parameters, as well as an attribute of the highest class speakers. Inside the pole piece there is a vent ending in a 45 degree bevel at both ends. The ring neodymium magnet is not visible as it is covered with the decorative rubber ring.

The inverted half-roll surround is made of low loss rubber. The surround is very thin and soft and is clearly different in appearance and feel from the surround used in the “paper” version of the Satori MR16P-8. As far as I know, the MR16TX-8 and MR13TX-4 models are the first time that SB Acoustics and Satori designers have used an inverted surround. It seems that the new surround is the main “feature” of the midrange driver and, quite probably, should leave its imprint on its sonic signature.

The four wave spider is made of modern BIMAX material.

The voice coil former has six vent holes through which the copper sleeve on the pole piece is visible.

The flexible silver lead wires are quite stiff and attached to the voice coil former symmetrically at 180 degrees. This contributes to better balancing of the moving system.

The gold-plated terminals are pressed into the aluminum holder and sit very firmly in it. Thanks to the large amount of free space around them, connecting to them is very convenient and simple.

The TeXtreme diaphragm consists of two layers rotated 45 degrees relative to each other. Unlike classic carbon diaphragms, it is perfectly smooth with a pleasant matte silky sheen and, thanks to the microfiber structure, shimmers very beautifully at different angles of incidence of light. The sound response of the diaphragm when tapped or stroked with a finger is very similar to the response of a ping-pong ball, there is no better association.

An unusual element is visible between the voice coil former and the diaphragm - a cone adapter made of TeXtreme. It serves to transfer and distribute force from the voice coil to the diaphragm in the most optimal point to reduce the excitation of parasitic vibrations of the diaphragm.

Visual inspection revealed excellent modern construction, beautiful design and excellent workmanship.

  Impedance frequency response

Prior to all measurements, the MR16TX-8 was broken-in with a sinusoidal voltage of 5.5 Volts/30 Hz for 30 minutes. The diagrams below show the impedance frequency responses before (green) and after (purple) the break-in at different scales:

It is a rare case when the broken-ing had very little effect on the parameters. “Right out of the box” resonant frequency was Fs=36.34 Hz, and after broken-ing it was Fs=34.99 Hz. The measured values of Thiel/Small parameters almost perfectly coincide with the datasheet, except for the DC resistance of the voice coil, which turned out to be 0.2 Ohm lower than the datasheet, and a slightly lower value of Qms=5.6 instead of 6.47 in the datasheet. The differences are absolutely non-critical.

The impedance response from 400 Hz to 10 kHz rises very slowly and linearly (on a logarithmic scale), reflecting the very low voice coil inductance (0.11 mH), achieved thanks to the massive copper sleeve in the magnetic gap and helping to reduce nonlinear distortion. At high magnification, a resonant peak at 5.27 kHz due to the main diaphragm resonance becomes visible. The very slight roughness at 1.3 and 2 kHz can still be somehow connected with the surround behavior, but what happens at 300 and 450 Hz, I have no exact explanation, perhaps something of this is related to the resonance of the lead wires. In any case, for such a rigid diaphragm in the range up to at least 1 kHz everything should be perfectly smooth.

The impedance response tells us about the well balanced low loss moving system (high mechanical quality) and the excellent motor.

  On-axis frequency response (at 315 mm)

Below are the axial unsmoothed SPL frequency responses for two MR16TX-8 samples measured in a test baffle at a distance of 315 mm to the microphone at 2.83 Volts:

The frequency response of both samples perfectly matches each other, even in the diaphragm's break-up mode. Up to the very top of the resonant peak at 5.27 kHz, the frequency response is very close to the datasheet. The measured sensitivity in the range of 150 Hz - 1 kHz was 89 dB, which completely matches the datasheet.

Up to 3.5 kHz the frequency response is very smooth with a small smooth rise in the band of 500 Hz - 3 kHz. The total unevenness between 150 Hz and 3.5 kHz does not exceed ±1.5 dB.

At 5.27 kHz there is a spike of about 12 dB caused by the main diaphragm resonance. The spike is quite neat and symmetrical, so it can easily be corrected with a single notch filter.

Higher in frequency, the diaphragm switches to a fairly controlled break-up mode of operation, accompanied by a series of surges and dips in the frequency response, the most noticeable of which is at 13.5 kHz, but it is not dangerous at all, as it is very narrow and far outside the operating range.

The engineers coped with the inevitable resonance of the surround perfectly - in the range of 700 - 1500 Hz everything is very smooth, without any dips and bumps.

At 420 Hz there is a very slight "notch", perhaps somehow related to small impedance fluctuations in this area.

I was interested in comparing the frequency responses of the new midrange and the MW16TX-4 midwoofer to see if anything had changed for the better. The characteristic of MW16TX-4 was shifted down by 1.5 dB:

As you can see, the curves are very close, almost identical. It seems to me that the midwoofer's response looks even a bit preferable. The resonant spike at 5.2 kHz is 3 dB lower in the midwoofer, the behavior in break-up mode is better controlled, there is no peak at 13.5 kHz. The frequency response of MR16TX-8 goes slightly higher after 6 kHz, which is due to the lower inductance of the voice coil (0.11 vs. 0.15 mH). The only thing that is better in the midrange is the absence of a small hump at 3 kHz. In general, anything above 3kHz has little effect on the sound, as it will be filtered out in the crossover, while anything below it is almost the same and it is unlikely that minor differences can cause significant differences in the sound of the speakers. Let's check this out in the “Listening impressions” section.

  Off-axis frequency responses (at 315 mm)

Below are graphs of off-axis frerquency responses - conventional and normalized, in which the axial response is taken as a reference, and the off-axis ones reflect only the difference with it:

The off-axis frequency responses are in perfect order. No unpleasant surprises were detected. In the range up to 4 kHz they decrease monotonically with increasing deflection angle and frequency.

  Harmonic distortion (at 315 mm)

Above are the dependences of harmonic distortion at voltages of 2 and 16 Volts, which correspond to average sound pressure levels of 86 and 104 dB, respectively. The measurements were taken on axis at a distance of 315 mm to the microphone. To limit overloading of the speaker in terms of diaphragm displacement amplitude, a second-order digital high-pass filter with cutoff frequencies of 50 Hz at 2 Volts and 80 Hz at 16 Volts was used when measuring harmonic distortion. In these graphs, we analyze the frequency range only above 150 Hz.

At all sound pressure levels, the entire operating frequency range is dominated by an exceptionally sonorous second harmonic. The behavior of all harmonics across the entire frequency range is stable at any SPL, there are no unexpected spontaneous bursts.

All harmonics increase with decreasing frequency, and the higher the sound pressure, the higher the frequencies at which the increase begins. At a sound pressure of 104 dB, for example, the growth of the 2nd harmonic starts below 700 Hz, and the 3rd, 4th and 5th - from 500 Hz. In the 600 - 2000 Hz range, distortion reaches its lowest values.

In the usual for speakers of this caliber problematic range of 700 Hz - 1.5 kHz, associated with the intrinsic resonance of the surround, everything is very good.

At 300Hz and 420Hz there are distortion spikes, i.e. in the same place where we saw the impedance roughness. Apparently, some unexplained undesirable processes still occur here, although they are quite insignificant.

In general, I would rate the overall level of harmonic distortion as “very low”.

  Voice coil current harmonic distortion

This type of measurement, despite its simplicity, is a good tool for assessing the linearity of the speaker motor. The diagrams above show the frequency responses of the 2nd, 3rd, 4th and 5th harmonics of the voice coil current at a voltage of 2.83 V (with the 2nd order high-pass filter with a cutoff frequency of 50 Hz).

Voice coil current nonlinearity is the direct nonlinearity of the mechanical force driving the speaker cone, since this force is related to the current by a simple relationship F=B*L*I, where B is the magnetic field strength, L is the length of the voice coil wire inside the magnetic gap and I is the current. The level of current distortion largely determines the minimum level of distortion that can be obtained from a speaker.

Nothing unusual in the behavior of harmonics is observed. Everything is good, everything is smooth, without unexpected spikes, except for the frequencies of 300 and 420 Hz. The usual growth of all components with a decrease in frequency at the bottom of the operating range. I would rate the overall level of current harmonics as "very low".

  Intermodulation distortion

The intermodulation distortion measurement is one of way of to analyze the device non-linearity. It is not an alternative, but an additional method and allows you to identify the spectral components of the inharmonious structure, which are much more harmful for high-quality sound reproduction and to which our hearing is more sensitive.

For testing I chose the frequencies 125 and 1063 Hz with ratio (1:8.5). In this case the Doppler distortion is not yet dominant and the contribution of amplitude modulation can still be observed. The fractional coefficient eliminates the superposition of harmonic and intermodulation components on each other.

The intermodulation distortion spectra for these frequency pairs are shown below. However, in these plots products of the motor nonlinearity are mixed with products of inevitable frequency modulation due to the Doppler effect. How to determine who is who? We can analytically estimate the level of the first pair of the side Doppler components using the following formula [http://www.linkwitzlab.com/frontiers.htm#J]:

As(dB) = 20*log10(pi*A1*f2/c), where pi=3.14, A1- the modulating signal amplitude in meters, c=343 m/s, f2 - carrier frequency. In our case f2=1063 Hz.

The amplitudes of the modulating frequencies were obtained by calculation, based on the SPL and the diaphragm area. After that, the estimated maximum level of the 2nd order spectral components (IMA2Doppler) corresponding to Doppler distortions was calculated:

If the measured side spectral components are higher than these values, then the speaker nonlinearity and the amplitude modulation are predominant, if lower, then the Doppler distortion and the frequency modulation caused by them is dominant.

For a voltage of 2 Volts, the measured IMA2 values were -47 dB, which is slightly above the Doppler threshold of -49.89 dB, meaning that in the intermodulation distortion spectrum, amplitude modulation is about on par with frequency modulation.

For 8 Volts, the measured IMA2 values were -31 dB, which is noticeably higher than the Doppler threshold of -37.85 dB, meaning that amplitude modulation dominates over frequency modulation.

Overall, I would rate the level of intermodulation distortion at midrange frequencies as “very low”.

  Step response

The step response rises very quickly and returns aperiodically to the resting state, but it is far from ideal, as it is spoiled by a strong oscillatory process from the main diaphragm resonance on the falling section. After filtering in a crossover it promises to look very beautiful.

  Waterfall

A waterfall shows the same effects as the step or frequency responses, in addition to exposing hidden resonances that are difficult to see on other types of measurements:

No new resonances are detected. We see a very clean, flawless waterfall up to 3.5 kHz and a series of rather quickly fading resonance “tails” at 5.27 kHz and 13.5 kHz after the diaphragm goes to the break-up mode. After 3 ms the waterfall is already completely quiet.

  Listening impressions

After the objective testing stage was over, as usual, I moved on to subjective evaluation of the sound. The speaker was listened to, being installed in the test baffle, in the following sound reproduction chain: Laptop→EMU 0404 USB→ DSP Xilica XM2040→Purifi 1ET400A

This is not my first experience of listening to speakers with TPCD diaphragms (see Satori MW16TX-4, Satori MW19TX-4, Satori TW29TXN-B, BlieSMa M74T-6, BlieSMa M142T-6) and from the MR16TX-8 I heard the same familiar signature. The following are the main distinctive, so to speak, “generic” features of the sound of speakers with diaphragms from TeXtreme (this is how I hear it personally):

• Natural, neutral or closer to warm timbre. Less colorful than paper and fabric diaphragms, less ringing and bright than metal or ceramic diaphragms
• “Solid”, dense and dynamic sound with excellent reproduction of sound attack. The sound is closer to, but inferior to, metal or ceramic diaphragms, but superior to paper and fabric diaphragms Percussion and string plucking are excellent
• High resolution and transparency, without a veil and any turbidity of soft diaphragms (paper, polypropylene, fabric). In these parameters, it is a little inferior to metals, ceramics and diamond, but superior to paper, polypropylene and cloth
• Characteristic velvety sound, especially noticeable on wind and string bowed instruments, as well as vocals
• A slightly lower sense of body, tactility of sound images and “blackness” of the musical canvas than than that of paper and fabric diaphragms
• No audible distortion or shoutness even at high volumes

I had no illusions about the sound character of the new midrange speaker, so both before and after the measurements I was most intrigued by only one question - would it have any new, special subjective sound characteristics that would allow it to be assigned the status of a "true" and not a nominal midrange speaker. So far, if we focus only on objective measurements, the MR16TX-8 beats MW16TX-8 midwoofer by only 1.5 dB in sensitivity. Comparison of nonlinear distortion, frequency response, waterfall and step responses is not in favor of the MR16TX-8.  If I were to choose a speaker for midrange duty, focusing only on these measurements (and alas, I don't have any others and the manufacturer doesn't provide any either), I would probably choose the MW16TX-8.

 As we know, correlation between measurements and listening impressions exists to some extent, but no one has yet been able to fully predict the sonic signature of a speaker by relying only on its measurements. If anyone knows of such cases, please let me know. That's why I always include a “Listening impressions” section in my reviews and consider it as important as the other purely technical sections.

Fortunately, I had the opportunity to compare the sound of the MR16TX-8 and MW16TX-8 side by side, as they say, here and now. Both speakers were filtered in the range of 300Hz - 3kHz with steep roll-offs outside the band.

So, the first seconds of comparison and... here it is, the moment of truth! Despite the very great similarity in sound, there were easily audible differences. MR16TX-8 sounded a little more detailed, transparent, light, open and expressive. There was a feeling that some very light veil, which I had not even suspected before, simply disappeared and the sound became even more clear. I'll be honest, I didn't expect such an effect. I don't know what design features influenced it - inverted suspension, lower inductance or slightly lower mass of the moving system, or perhaps the whole combination of these factors, but the fact remains. I'm sure the designers at Danesian Audio ApS know exactly what they are doing.

So, the answer to the question “whether to take the new MR16TX-8 instead of MW16TX-8 for the midrange duty” is unequivocal yes, yes and yes again!

  Рекомендации  по  применению

Based on the measurements, the MR16TX-8 can be recommended exclusively as a midrange driver for high-quality multi-way loudspeakers. The potential operating frequency range may lie between 200 Hz and 3 kHz. The exact value of the lower limit will depend on the maximum required loudspeaker's SPL and your tolerance for non-linear distortion, and the upper limit will depend on the required directivity of the loudspeaker and the tweeter used.

The volume of the required enclosure will depend on the type of acoustic design. A closed box will require at least 5 - 7.5 liters, and a bass reflex will require about 14 liters.

  What is the price and where to purchase it?

The retail price of MR16TX-8 is on average from €238/piece to $335/piece excluding VAT. You can buy it in the following online stores:

• madisound.com
• audio-hi.fi
• toutlehautparleur.com
• soundimports.eu

​

  Summary

The new MR16TX-8 midrange was an excellent extension of the Satori-branded TPCD diaphragm speaker series, did not disappoint at all, but on the contrary, very pleased. The measured parameters and characteristics coincided well with the datasheet and confirmed the speaker's belonging to the top league. Now, finally, the Indonesian company Sinar Baja Electric has a full range of TPCD speakers of special purpose (woofer, midwoofer, midrange and tweeter), which opens up opportunities for designers to build loudspeakers from bottom to top on drivers with identical types of diaphragms and sound signature, which has a very beneficial effect on the fusion and integrity of the sound of the loudspeaker as a whole.

What I liked:

• Very low harmonic distortion in the 400 Hz - 4 kHz range
• Very low intermodulation distortion
• Very low mechanical losses
• Smooth frequency response up to 3.5 kHz
• Neutral timbre, high detail and sound transparency
• Excellent consistency of parameters from sample to sample
• Excellent workmanship

What I don't liked:

• Unexplained minor artifacts at 300 and 420 Hz
• Increase in 2nd harmonic below 500 Hz

More detailed measurement results can be found here:

MR16TX-8

Yevgeniy Kozhushko/10.02.2025