Review: Beyma 14MLEX1000Nd

Norms broken. Dimensions ignored. That was the way of looking at things for some time when it came to these sizes. Now, these are not unconventional anymore. Following that spirit, Beyma also introduced its entry into the mid-size class: the 14MLEX1000Nd - a driver large enough to deliver serious sound pressure levels in the newer, compacted package.

Why 13.5"? Why 14"? Why 16" and 19"?
Why not stick to the long-standing dimensional standards of driver design? That could be a long essay for a very rational situation. Let’s skip that.

We don’t do these drivers just because we can. These dimensions do bring comfort in logistics and handling, and they are creeping into the mainstream rather fast.

This review was sponsored by MS-Sound (www.ms-sound.cz), who kindly provided the speaker for testing. While sponsorships are very welcome, all technical results and measurements remain completely independent and unbiased.

Looks and build quality:

If sleekness was a speaker, this would be it.
At first glance, it gives off that incognito, plain, reference look — not even disrupted by Beyma’s now-familiar X-shaped spoked basket. The moderately heavy, “wetted-look” cone coating, dark spider, and distinctive yet still design-wise understated magnet return cap all add to that dark horse vibe. Maybe the copper-color tinsel leads woven into the spider break that visage a little.

Let’s peek under the hood:
On a 14.13" basket platform sits fairly deep curved smooth cone. 7" Conex spider with roughly 3.5 corrugations centers a 4" inside-outside copper-wound voice coil It is a single spider design with advanced heat and fatigue resistance, yet not quite positioned in full subwoofer-grade territory, to keep things moving efficiently for midbass workloads. Fairly stiff 5,5"-ish dustcap glued to the speaker cone blends in the plain design.

Beyma markets this model as a low-and mid-frequency transducer, and while it can certainly handle some basic bass duties, it’s not built for constant punishment around or above Xmax. The cone’s design adds to that vibe - capable of bass, but not the kind that forgives reckless abuse or heavy horn compression. For midbass or full-range work, though, it looks more than solid and confidently engineered. On touch, it feels stiffer than competing products for sure.
Will I spare it from the inevitable abuse? Of course not. In the spirit of “Will it bass?”, I´m putting the foot down.

The magnet cap measures 144 mm in diameter, expanding another 10 mm toward its base, into ~170 mm including top plate. The motor assembly stands 70 mm tall. A flared center vent is 44 mm wide and 70 mm deep before it meets inner protection wire mesh. Around the voice-coil axis, six 7.5 mm vent holes provide direct cooling, while another ten openings at the basket base complete a notably airy design implied by Beyma´s own claim of "Ultra low air noise".

More design efforts were summed into the features and specs overview:

● Low power compression losses

● Optimized linear behaviour

● Extended controlled displacement: Xmax ± 11 mm

● Exclusive Malt Cross® Technology Cooling System

Let´s stop here at the Xmax figure. For a midbass driver, that´s a lot. Seemingly over the top. Almost too much. In closer look, mathematical Xmax derived from voice coil length and pole piece thickness gives us 7 mm coil overhang. 7mm of excursion with rather fully utilized voice coil, and then some for the peaks. What does that mean really? More coil mass deals better with heat dissipation, full pole piece coverage gives us low distortion figures at the excursion limits of midbass work, and 6-8mm excursion is also usual doppler distortion limit for clean output if we crossover properly. With modern even higher excursion subwoofer drivers, I believe this will be the new trend. A midtop section giving adeqate output down to 80Hz, to strongly support proper and modern subwoofers.

Driver specifications:

• Size: 14" type
• Power Handling: 1000 W AES
• Impedance: 8 Ohm
• Frequency Range: 50-4500 Hz
• Sensitivity: 99 dB (1W/1m)

T&S parameters set:

Xmax of 11mm is very respectable as is, for any midbass driver, albeit heavy type one. The measured Xmax value includes a “plus” suffix, as the driver performs admirably under overload conditions - maintaining control and composure beyond its rated excursion.

Now, measured T&S parameters are a fair match for a broken-in new unit (by my test procedure specs) with better Q values - Qes and Bl are very slightly above the published specs. But we can see changes in the suspension and compliance department, causing all that. The single spider indeed seems to be not dedicated for true subwoofer work.

Continuning with manufacturer´s supplied frequency response:

Below attached is the product datasheet:

Performance overview and general rating:

The driver performed well within its specifications for intended use. In free air, it sounded strong and snappy; lively and "shouty" for a midbass unit in a way to be liked for live sound.

Advertised "ultra low self noise" claim works great for sinusoidal signal, for program content less so. The motor is clearly audible, yet controlled, and 14" dimension gives it slight edge to the SPL/motor noise ratio in comparison to standard 12" speaker types. It is an inevitable compromise, and I believe Beyma handled that favourably. Not quiet, not loud. Just good. And that´s more than enough for a mid-format size class with extended displacement volume capabilities.

Great performance, output and all the figures are paid for with some kind of price. In this case, it is weight - To keep big coils and strong cones running, it is 9,2 kg for a midbass. That is not a little, and monetary price is not to be ignored either.

• Buy if: You want the high end midbass driver for proper integration with modern large excursion subwoofers.
• Skip if: You want to move a lot of air by a light driver for little money.

The displacement-to-dollar score again makes it clear: this is a driver built for specific applications. I’d not recommend it blindly for general-purpose builds, or for scenarios where displacement to price ratio matters. Once we assign the driver to the type and performance or proper use case, this issue gets rather resolved.

*The following section is available to Bassometry members only.* (Free sample):

Large Signal Performance Results:

This section presents the driver’s behavior under high excursion and high power conditions. Measurements are conducted using controlled lab procedures to reveal transducer behavior beyond small-signal specs. For a full explanation of the test methodology, please refer to our Bassonomy section.

Upon first test signal injection, I must say I am impressed. A midbass or fullrange driver behaving great past 11 mm of excursion one way is no small feat. Let´s unpack the performance details:

Measured data look VERY strong. In the case of resonance frequency shift of just 17.1%, the shift figure appears too strong again, due to the pre-test resonance change caused by the burn-in procedure, which hides the true resonance shift, derived from the manufacturer-specified value. This is expected to happen with a single spider, but it is not favourable for a driver in heavy bass use, which is what we do here.

Pre-burn-in stats would bring an 84% score; with the additional resonance shift penalty applied, this puts it down to a 53.4% score on this test. That does not mean the driver is not good or does not survive. Rather, it means that it is being overstrained for subwoofer work. It will further be practically tested with prolonged bass torture, despite its different native classification.

Impedance shift at Xmax of 57,6% indicate more of the nonlinear creep/behavior of high compliance drivers. With the permanent resonance frequency shift, the driver performed in fully stable manner despite further abuse.

DC cone offset at 15Hz: 0.11mm (1%) frontward offset shows remarkable control despite softer suspension. Very solid cone control.

15 Hz – 50 Hz at Xmax (Sweep) Behavior:
During frequency sweeps, the offset rose to 0.2 mm. Impeccable performance showing not only good centering but also excellent underlying control of the magnetic circuit, giving both offset values a 100% score. I have tried to abuse the driver to 75Hz, and I could see onset of some instabilities with 1.8 mm offset. But this is still very good behavior, and little outside the bounds of any sane usage while at that. Consider this driver very stable.

Power draw tests: All ending up with 100% respective scores. These point to the looser suspension, giving this driver favourable sensitivity and efficiency figures needed for mid-bass use.

THD figures: Barely above set ideals, yet this is for 11mm of excursion figure. Not exactly midbass work. Still great number, expected to be lower in proper deployment and range of work. I.E.: theoretically borderline inaudible. 84% and 90% is a nonissue in expected excursions peaking at ~8-9 mm.

Excursion behavior:

Here, usable excursion would have risen to +3 dB above Xmax, especially mechanically and in terms of distortion as well, while moving the speaker cone by 14.4 mm each direction. The 14MLEX1000Nd also absorbed a controlled +4 dB boost without any reliablity issues at that time. While it sounded mildly stressed, its small-signal T&S parameters showed no noticeable change afterward (other than further Fs shift that healed after 48 hour resting period).

The usable excursion score was ultimately reduced to +1 dB due to the previously mentioned suspension strain and Fs shift. Within the normal operating range, however, the 14MLEX1000Nd would remain within specified margins.

Mechanical(SPL) compression:

With Beyma, we can see similar values upto Xmax limit again, showing "long" suspension with superlinear behavior. This is great news for midbass work, up to the survival capabilities of the suspension itself.

Final words:

This is a beautiful strong midbass driver, that brings previously unexpected output and (mid)-bass performance to the systems than can no longer be crossed over at 100+Hz feasibly. To be frank, being tired of most systems showing significant gap in their respective bass crossover frequencies, I am contemplating on getting this one for myself as well - to get that "butter-bath" of velvety full midbass sound, that is so missing in many, if not most current products and designs. Competition brings this and that, but not favourably sized 1000W unit that has coil to spare for some higher than usual peaks in the program content. Or full spectrum support down to 80Hz, where modern bass solutions get heat strained or muddy. The weight and monetary price is basically inevitable, there is no fair reason to bash this driver for what it is supposed to be. Just be prepared that the compact box does not mean light box. It will be one dense cluster of speaker technology.

For outright heavy bass duty, it seems to be little underequipped in soft parts, but 500hr test is being conducted anyways, and if the driver survives what it is not meant to, the bassometry reliability badge will be honored additionally for its excellent featureset and reliability.