Low-cut filters: differences, use cases

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filmguy123

New member
I have the Sennheiser 8060 and the associated MZF8000 capsule:

https://www.bhphotovideo.com/c/product/677556-REG/Sennheiser_MZF_8000_MZF_8000_Filter_Module.html

Low Frequency Cut
-3dB @ 160Hz (Switchable)
-3dB @ 16Hz (Fixed)

I also have the Rycote Tac!T in-line low-cut filter:

https://www.bhphotovideo.com/c/product/861407-REG/Rycote_017022_TACT_T_FILTER_CABLE_18_XLR3F.html

18 dB per octave
Low-cut at 60 Hz
Signal Loss: 0 dB at 1 kHz, -3 dB at 63 Hz, -40 dB at 14 Hz

And finally the SoundDevices MixPre-D, which has the switch for a low-cut at 80 and 160.

A few questions:

1. What is the practical use-case difference between these, and when might I prefer one over the other?

2. Is it bad to double-stack these, or would that have no effect if they are both cutting off the same frequency?

3. I need to shoot some content before I have a chance to play with all of these in depth. Until then, will leaving the MZF capsule and Tac!T filter out of the fix, and just flipping the MixPre-D to 80hz cut off switch do the trick fine as a general purpose low-cut / rumble safe guard?
 
1. The Rycote Tac!T is particularly useful when you have no low-cut on a mic and want to cut excessive low frequencies before they get to the preamp: I have one, but rarely use it (it was useful some years ago when I used to boom a MK012 hypercardioid, which was prone to excessive handling and wind noise). The MZF8000 is more subtle, doubtless much better quality, and is recommended for boom use, for the same purpose. The Mixpre-D low cut options (which are at 6db per octave) are, obviously, later in the chain, but much easier to switch on and off and for most uses - i.e. where low-frequency noise isn't overloading the preamp - fine: the 80Hz and 160Hz values are very useful.
2. You can double-stack them: the low-cut will be cumulative.
3. We have no idea what or how you are recording (e.g. booming, what wind protection and what mic suspension, what sound source - e.g. female voice): if booming and I had a MZF8000 anyway, then I would use this with its fixed -3db low-cut filter on, and I would probably just use the Mixpre-D 80hz and 160hz to taste depending on how much wind, handling noise, low traffic rumble there was and the nature of the source (e.g. low adult male voice vs higher child or female voice), with the advantage that you can monitor this properly while switching.

More generally, it would be worth - given the range of threads you are starting - to do some background reading asap, so that your understanding catches up with your gear! A good suggestion of Jay Rose's book has already been made. And experiment: it takes less time to swing a boom with and without the MZF8000 160hz low-cut on than to type a query here!

Cheers,

Roland
 
Thanks Roland! Yes his book is already on the way from Amazon plus two others

I am booming on a Cinela wind cage but to change the mount from 8060 to 8060 + MZF is an entire swap and I have only had last night to test for this interview.... indoors... as it’s rainy! Much appreciated help :)
 
1. What is the practical use-case difference between these, and when might I prefer one over the other?
- Attenuate low frequency rumble from trucks aircraft ect. I try to eliminate LF content prior to reaching the mic. Severe wind can distort the mics capsule producing broad band distortion, so a HPF will not help in that scenario. Too steep a filter can 'thin out' a voice, for instance, my old 1st gen Shure FP32 did this (12 db per octave @ 150Hz as I recall). I leave the SD 302's 80Hz HPF engaged most of the time for dialog, as the human voice has little content below 100Hz.

2. Is it bad to double-stack these, or would that have no effect if they are both cutting off the same frequency?
- The secondary filter does not do much if the frequency/slope are about the same. I generally leave the mic's 70-80 Hz filter engaged as well as well as the filter on my SD mixer or recorder. I would NOT use the digital filters on the budget gear at unless no others are available, they normally produce audible artifacts.

3. I need to shoot some content before I have a chance to play with all of these in depth. Until then, will leaving the MZF capsule and Tac!T filter out of the fix, and just flipping the MixPre-D to 80hz cut off switch do the trick fine as a general purpose low-cut / rumble safe guard? - I would start with the Tac!T filter in place, the closer the filter to the mic, the better. The Rycote in-line filter looks nice, and doubles as a pole > mic link. $65 is a lot though if you already have good quality filters on the mic and mixer. BTW, what mics/ transmitters are you using? They may have good filters already. Lectro's variable HPF in the transmitters are good, though lav mics rarely need much.
 
Can anyone give me feedback on the sound quality and what to do better next recording?

http://www.mediafire.com/file/tfxywh1wgel59jo/audio_sample_-_cinela_8060_shotgun_on_sounddevices.mp3

Outdoor interview
Boomed overhead
Cinela Pianimissio, OSIX mount
Sennheiser 8060. No MZF, no Rycote Tacit.
SoundDevices MixPre-D levels hanging out around 0 (-9 to +6 range). 80hz pass engaged.
Line out into GH5 Audio unit
GH5 recording with an approx -12db ceiling, commonly averaging -16db, occassional peaks to 6db.


Seems a little flat / 1 dimensional to me. Is that just the bass heavy 8060? Boomed overhead but subject moves a little, though pretty close. Maybe slightly off axis or slightly too far at times?

80hz pass on Sounddevices ok?

Or does this just need some audio sweetening to round out the dynamics?
 
It's kind of heavy in the lower mid, so I would cut out a bit there. If you were really close that might be proximity effect but?

The varying BG bugs me but if it's him talking and we see it's out doors then it's fine, if it's VO then you probably need to either clean up or cover up the BG.

The persons delivery isn't great. It's kind of over blown and flat at the same time. Again if it's an interview it is what it is. If it's a narrative film then the performance could use some polish. Though with out context who knows, this might be a perfect delivery for that place in the story?

Otherwise it sounds fine. I would scoop out some low mid. What I sometimes do is sweep a high gain notch filter to find the resonant freq in the voice and cut those down a bit. That is often gets rid of the muddiness with out altering the vocal characteristics as much as a broader scoop. Pull some of that out and the voice will seem more dynamic and less flat and it will also help with clarity, though you don't really have a clarity issue.
 
Thank you noisz! It's in a documentary style interview, but it's sort of being done as a quasi/authentic interview VS VO. The music should disguise some of the BG variance, but given the content should be ok.

Was more interested in the audio quality rendition of the mic, my placement, and the pre-amp settings I used. If all sounds good, it sounds like it's just his particular voice being overly heavy in the low mids? In a case like this, is there anything I should be adjusting ON SET - or is this just something intended to be done by an audio mixer in post?

Thanks again. Really appreciate the feedback!
 
No way to tell really from just listening. But in general the voice, the location, the placement, and the mic all contribute to problems (or goodness). So while I can tell you what I would do to "correct" the issue I can't really tell you what you could have done to prevent it. Some things are generally pretty decipherable but most could be any number of things and you really have to be there to troubleshoot which are contributing.

The take away is to listen for the problems. Most unexperienced people listen for what they want, most experienced people listen for what they don't want.
 
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