Sennheiser MZF 8000 ii

My series of field tests of the new Sennheiser MKH 8030 fig 8 (which kicked off with initial tests, moved on to mid-side recording, encompassed field recording, included comparison with the MKH 30, and most recently included use in a native B-format array) have led to various questions being asked of me, both via this blog and on sound forums. An interesting one was whether the mic needed the modular filter that Sennheiser make for the MKH 8000 series: the MZF 8000 ii. This filter was announced at the same time as the MKH 8030, in September 2023, but, as I understand it, was available beforehand as a special order option instead of the original MZF 8000. Both filter modules are the same in terms of the switchable -10 dB pad and the fixed low-cut filter of –3 dB @ 16 Hz (18 dB/oct), but differ with regard to the switchable low-cut filter: on the newer filter the latter is –3 dB @ 70 Hz (18 dB/oct), compared to the original’s –3 dB @ 160 Hz (which was much less steep too: I can find no authoritative specs). This stems from understandable user feedback, since a lower and steeper HPF around the 70 Hz frequency of the new filter is of more use to broadcast and filmmaking sound for those mics in the MKH 8000 series that don’t have in-built bass roll-off (i.e. all except the MKH 8060 and MKH 8070 shotgun mics): more use, that is, for reducing low-frequency wind noise and handling noise.

While some might (and, indeed, do) lament the absence of a built-in pad and switchable low-cut filter in the MKH 8000 mics, as found in the earlier MKH mics, the modular nature of the MZF 8000 ii filter means it is more flexible and, also, the end result is quite different. Flexibility is seen in the fact that the MKH 8000 mics, sans filter, can be kept small and, moreover, when the filter is used, this can be placed either between the head and the XLR module (making for a 29mm longer mic) or, if using an MZL cable, well away from the mic head, and next to the (then remote) XLR module. As for sonic differences between the MZF 8000 ii and the in-built equivalents of the MKH 30, 40 and 50, arguably the fixed 16 Hz low-cut filter of the former simply compensates for the increased bottom end of the MKH 8000 series mics, but there remains quite a difference in the switchable low-cut filters: the MKH 30, 40 and 50 have much higher and gentler low-cut filters, designed to address proximity effect, rather than the lower and steeper filtering of the MZF 8000 ii filter that is geared to reducing wind and handling noise. And, to add complexity, the MKH 20 switchable filtering is only concerned with high frequencies, being to modify the mic between near and diffuse field applications (with, of course, the proximity effect not applying to an omni anyway). The earlier MZF 8000 filter, therefore, was more comparable to the switchable elements of the MKH 30, 40 and 50, while the newer MZF 8000 ii is more overtly geared to production sound.

OK, so much for the theory: how does the MZF 8000 ii perform? With the focus of the MZF 8000 ii on production sound, I fitted the filter to one MKH 8030 and mounted a pair of the mics in Rycote Invision 7 shockmounts to a short stereo bar on the end of a carbon-fibre boom pole. First off I compared the impact of mild shake (from straining muscles) on the two mics, with no high-pass filter (HPF) on the recorder, and just the fixed 16 Hz low-cut filter on the one with the MZF 8000 ii module fitted.

As expected, the MZF 8000 ii filter removes a significant amount of the infrasound, whilst having little impact on other low-frequency performance.

Moving on now to compare the effects of using the high-pass filters built-in to most recorders and mixers versus, or in conjunction with, that of the MZF 8000 ii filter, first of all I repeated the boom pole test with one mic with the recorder’s 40 Hz HPF (40 Hz being the lowest setting on Sound Devices 788T) with the other mic using the MZF 8000 ii’s 16Hz filter and the 788T’s 40 Hz HPF:

Again, as expected, the 16 Hz low-cut filter of the MZF 8000 ii adds significantly to reduction in handling noise from the boom pole by use of the recorder’s 40 Hz HPF.

For most such boom pole (or, indeed, pistol grip) mounting of a mic of course one would anticipate using a higher frequency HPF such as the switchable one built into the MZF 8000 ii, so that formed the next test: i.e. comparing the Sennheiser module with the 70 Hz HPF of the Sound Devices 788T.

Going by the frequency of the two HPFs some might expect that the results would be same, but the MZF 8000 ii’s 70 Hz filter has a much steeper slope (18 dB/oct) compared to that of the 788T (selectable at 6 dB/oct or 12 dB/oct: I used the latter), and this difference is clear. By contrast, the more recent Sound Devices 8-series and Mix-Pre recorders have 18 dB/oct HPFs, so the final test with the boom pole compared the MZF 8000 ii’s 70 Hz HPF to that of a MixPre-3: the latter only goes up in 20 Hz steps, so was set at 80 Hz.

Given the steepness of the slope and the slightly higher frequency, the MixPre-3 shows more attenuation of boom pole handling noise.

So far, this is all very much as expected from the specifications: but where does this leave us? What are the benefits of the MZF 8000 ii in terms of its HPF if the recorder/mixer has one too? And, likewise, what is the benefit of the -10dB pad if, as is sometimes the case (e.g. the 788T), the recorder can supply 48v phantom power in line-input mode to cope with mics recording very high SPLs and consequently producing high outputs? Well, this is complex, and will reflect the type of material being recorded, the modus operandi of the sound recordist, and the capability of the mixer/recorder. In some cases, stacking HPFs (i.e. in both the mic and the recorder/mixer) may be useful to give a steeper slope: this is especially relevant if the recorder itself doesn’t offer anything as steep as 18 dB/oct. In many uses the fixed 16 Hz HPF of the MZF 8000 ii will be useful to remove unwanted infrasound, and many mixer/recorders do not have HPF options that go this low. In some cases the MZF 8000 ii will stop the mixer/recorder preamps being overwhelmed by, or giving too much headroom to, unwanted low frequencies: this is especially relevant with those recorders (such as the Zoom F8n) where the HPF comes after the trim/gain and ADC. Of course, any such uses need to be balanced against the additional weight of the module (relevant at the end of a long boom pole) and the lack of accessibility of switches if the mic is in a windshield. And it also needs to be considered against other options that are outside the mic or the recorder/mixer, such as the switchable 80 Hz HPF built into the XLR mount of the Rycote Nano Shield (and therefore accessible outside a windshield).

So, in short, it will come down to personal choices: the module is primarily of use to those for whom mic handling noise, wind noise, unwanted low-frequency ambient noise, and, for the pad, extreme SPLs are issues, which will mainly comprise production/ENG sound, sound effects recording, and, to a lesser extent, field recording. As for using the MZF 8000 ii with the MKH 8030? Well, although this has a decent bottom end for a fig 8 mic, it naturally has less in the way of a low-frequency response than its omni, wide cardioid, cardioid and supercardioid siblings and is also less likely to be swung around vigorously on a boom than, say, the supercardioid MKH 8050. In short, to date I haven’t found a need to use the MZF 8000 ii with the fig 8 MKH 8030: others may draw different conclusions. However, I’ve found it useful to have the MZF 8000 ii in the kit, and so far have used it most with just the 16 Hz low-cut filter with the MKH 8020, where the very bottom of the extended low end of this omni mic isn’t always wanted: and its good to be able to have the 70 Hz (18 dB/oct) filter and the -10dB pad there for whenever the need arises. Turning this around the other way, and again unlike some others, I’m glad that with the MKH 8000 series mics Sennheiser took a modular view to the HPF and pad capabilities since, for the bulk of my recording activities (and I suspect those of so many others), they aren’t needed and the consequently more compact form is useful: evidently the MZL cables take that compactness further, but that’s another matter!