CARMUS Review of our VIBE CVEN Midrange & Tweeters

The packaging of this acoustics flaunts proudly ‘Made in England’, although there is more to it. No, no, it was not made at all where everything else is done today (well, you get the idea). The speakers are indeed made for the English company Midbass Distribution (owner of the VIBE brand) by their Italian partner Francesco Richichi.

The acoustics are not cheap, so far only a few sets have come to Russia, one of which ended up in my laboratory. I won’t say the exact price, I don’t have such information, but the three-line lasts for a six-figure sum in rubles. All components are sold separately, which means they can be docked in either 3-way or 2-way systems. The speakers are assembled by hand and each pair has its own number.

The speakers are matched to each other in terms of parameters. Each set comes with its own sheet with individual measurement results. A serious approach for a serious set of speakers!

FIRST ACQUAINTANCE, CONSTRUCTION

I’ll start with the MIDBASS speakers. They look brutal, quite heavy, Carbon fibre diffusers, cast baskets and large motors.

The diffusers look light (and measurements later confirmed this, Mms is less than 12 grams, which by today’s standards is less than the average for a 6.5-inch caliber).

The large axial channel is closed with a porous insert that acts as an acoustic load and dampens air movement.

It is not possible to reliably determine the geometry of the voice coil – the upper washer of the magnetic circuit is hidden by the lower flange of the mighty cast basket. But by indirect indications, it can be assumed that the ratio of the working turns of the coil to the length of the winding is high here, and this promises good control of the movement of the diffuser.

The midrange here is quite interesting and unusual – only 2 inches in size. Their outer diameter is only 6 cm. The mounting depth is 3.7 cm. At first there was an assumption that they could work as broadband speakers, but this was not confirmed: they climb up well, but tweeters will not replace themselves. But downstairs they feel unexpectedly confident for their caliber.

The cones of the cones are made of cellulose composite, and the caps, like those of the woofers / midrange speakers, are carbon fibre.

Magnetic systems are based on neodymium magnets. Here, too, there is a large axial channel closed with a porous liner – acoustic load.

The tweeters have exactly the same outer diameter as the midrange – 6 cm. The soft fabric domes are slightly recessed, their framing forms a kind of short horn. This is usually done to correct the recoil at the very top and obtain the desired radiation pattern. Then, when measuring, by the way, I will pay attention to this.

But on the back side – a surprise. The tweeters have an open acoustic design, so you can’t put them in the same volume to the midrange, you need to separate them. And yes, the dome space here also communicates with the “outside world” through acoustic loading.

There are no grilles for the MIDBASS speakers, but graceful metal rings with protective arcs go to the “middle” and tweeters. By the way, they are absolutely the same (outer diameter – 6.4 cm), so that the installation of the midrange / high frequency link can be made at the same time compact and beautiful.

MEASURING ELECTROMECHANICAL PARAMETERS OF SPEAKERS

Although the parameters are given for each copy of the speaker, I decided not to give up my own measurements. The scatter in pairs is small, so I am giving the average values, there is no need to delve into the details.

The measured parameters of the Vibe CVEN6.5SQW-V9 LF / MF speakers:

  • Fs (natural resonance frequency) – 58 Hz
  • Vas (equivalent volume) – 17.8 L
  • Qms (mechanical quality factor) – 11.61
  • Qes (electrical quality factor) – 0.36
  • Qts (full quality factor) – 0.35
  • Mms (effective mass of the moving system) – 11.7 g
  • BL (electromechanical coupling coefficient) – 6.3 T m
  • Re (DC Resistance) – 3.4 Ohm
  • dBspl (reference sensitivity, 1m, 1W) – 91.8 dB

Measured parameters of midrange speakers Vibe CVEN2.5SQM-V9:

  • Fs (natural resonance frequency) – 132 Hz
  • Vas (equivalent volume) – 0.2 l
  • Qms (mechanical quality factor) – 4.95
  • Qes (electrical quality factor) – 0.85
  • Qts (full quality factor) – 0.73
  • Mms (effective mass of the moving system) – 3.0 g
  • BL (electromechanical coupling coefficient) – 3.3 T m
  • Re (DC Resistance) – 3.8 Ohm
  • dBspl (reference sensitivity, 1m, 1W) – 79.4 dB

Midbass speakers. Unusually strong motors, soft suspensions, light movements and very high sensitivity.

Midrange. Unexpectedly low resonance frequency for a 2-inch caliber. The mass of movement is clearly not like a broadband speaker, but rather like a normal 3-inch midrange. The full Q-factor of Qts promises an extension of the operating frequency range down to almost Fs. But this point still needs to be studied, so it’s too early to rush to conclusions.

Tweeters. How many tweeters have you seen with a main resonance of 350 Hz? I’m something offhand and I don’t remember such among car models (and in homework this is not found on every corner). However, very slight traces of resonance are also visible at 2 kHz.

VIBE CVEN6.5SQW-V9 WOOFER / MIDRANGE PERFORMANCE ANALYSIS

Due to the unusually strong motor and, accordingly, the low value of the electrical Q-factor, a gentle decline in the frequency response is obtained with decreasing frequency. This is both good and bad at the same time – depending on how the speakers are used.

For example, for a two-band, this is not very good, because the effect is “lack of bass”, that is, when the bass is good in structure, but you want to add it. But in a three-strip, such a gentle drop is easily levelled by the settings of the joint with the midrange, but the bass accuracy comes to the fore – not an ounce of hum, excellent impulse response and a very clear, correct punch.

In principle, the graph of distortions clearly shows this. Please note that the distortion does not increase with decreasing frequency, as in ordinary speakers with the usual “car” Qts of about 0.7. That is, the speaker is perfectly controlled by the amplifier and does not run out of gear at its resonant frequency.

Above in frequency, everything looks decent too. There are no resonances in the suspensions, although the diffusers are thin and light, they are well damped and their piston mode of operation turns into modal smoothly, without loud hysterics and bursts of frequency response. The phase response is flat up to about 4 kHz, and above the physical dimensions of the speakers just start to affect.

ANALYSIS OF THE MIDRANGE SPEAKERS VIBE CVEN2.5SQM-V9

The middle ones are built a little differently, but conceptually they are also very interesting. Look, the frequency response confidently starts from about 200 Hz (and this is with a caliber of 2 inches!) And goes up, without moving, to about 4 kHz.

However, I would not say that they can work normally from 200 Hz. Firstly, whatever one may say, and this is 2 inches, it is wrong to drive them almost into the upper bass. Secondly, they do not have such a powerful motor, so when the frequency is lowered, distortion begins to increase. Judging by this characteristic, then I would take 300-400 Hz as the lowest border of their range, lower in any case is unreasonable.

In principle, the speakers climb up quite well, but these are far from broadband speakers. It is logical to make the joint with tweeters no higher than 4-5 kHz – it is up to this frequency that the speakers work with the correct, linear phase characteristic.

VIBE CVEN1SQT-V9 TWEETER PERFORMANCE ANALYSIS

Own frequency response of the tweeters can be called “correct silk” – the domes do not start playing with waves at separate frequencies, everything is smooth, predictable, and controllable. And also pay attention – when turning, the nature of the frequency response practically does not change (here is the shape of the flange framing the dome). This gives freedom in installation – it is not necessary to subtly catch the direction of the tweeters in order to get the desired treble character, small angles of rotation are quite acceptable.

As the frequency is lowered, the distortion grows smoothly. However, it must be remembered that tweeters have an open design, so, despite the formally low resonant frequency, the HPF setting should not be greatly lowered. Yes, this is actually not necessary – the optimal junction with midrange is just obtained in the region of 4-5 kHz, and up to this mark the tweeters work normally.

An even phase characteristic is another confirmation of the correct behaviour of the domes. If resonances appeared in them, steps and sharp drops would appear on the graph. Here, everything is smooth.

WHAT ABOUT THE SOUND?

Evaluating the sound, having only individual components, you need to be extremely balanced, because in a finished system, 80% of the character of the sound (or even more) is determined by the settings. However, you can still notice some characteristic moments.

Midbass speakers. 

Awesome accurate and punchy sound. I would hardly recommend them for a processor two-way band because of the “lack of bass” effect, but in a three-way band it is just a bomb. When the volume is increased, the speakers are not clamped at all, they do not begin to fade and buzz, the sound retains the sharpness and clarity of the MIDBASS range. Still, whatever one may say, but the elastic and legible MIDBASS is the basis of the emotionality of the sound.

Mid-range speakers.

Cognitive dissonance seems to be 2-inch babies, and the lower mids are given out as some 3-inch or even 4-inch speakers. This does not mean that they need to be forced to work so low, but the freedom in setting up the joint with the MIDBASS link is great. Above – yes, indeed, they need tweeters, they are not broadband. When installing, it is advisable to provide them with sufficient volume on the back side: in tight cases (I tried 150-200 ml), the sound dynamics is slightly clamped. When installed in test 2-litre boxes, the sound was revealed somehow more fully.

Tweeters. 

Good, correct, silk. They sound beautiful and detailed, not a drop of harshness or any colour in general. Without artificial “air” in the form of ultrasound input, but in the informative range, the supply is very light, with excellent micro dynamics.

PRO’s

  • Serious construction, high-quality assembly
  • Unusually compact midrange
  • Emotional, punchy MIDBASS range
  • Delicate and detailed tops with a neutral character

CON’s

  • Small cable connection terminals

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