Zoom F8 limiters

scorsesefan

scorsesefan

Veteran
Apparently, the F8 limiters are digital and behind the A/D converter: https://www.youtube.com/watch?v=KYe-0cO2M8w

Is this a cost saving issue or just bad design? In any case, I believe the DR-680's are behind the A/D converter but are analog and the unit produces excellent sound.

My question is, would this deter anyone from buying the F8?

Thanks
 
If its a bad design to use digital limiters then most digital audio desks are then of a bad design.....
Please compare apples with apples, there is no point comparing a $1k recorder with a $6k recorder.

Its like comparing an Azden radio mic with Lectrosonics.

Remember the WhoHa with the Behringer X32 mixer and so many people rubbishing it prior to release, 12 months on it probably the fastest selling Digital mixer world wide.

My thoughts on the F8 is looks good, lets see what it can do in the 'real' world.
 
Couple of things. IF the DR-680 is using an analog limiter "behind" the A/D converter then they would need to have a D/A converter in front of that and another D/A converter after and that makes very little sense.

And the 680 is not anywhere close to $6K, so while you can sort of knock the video (except he doesn't compare the F8 with the Zaxcom, he just mentions what he has heard about the Zaxcom limiter) you cant ding the post.

The MixPre which is less (at least the original version was) than a F8 has limiters that work fantastic, so it's something that would be expected on gear aimed at what Zomm is aiming the F8 at.

That said the limiters seem to be about 90% there so as long as you hardly ever need them you are probably OK.

It probably wouldn't be a deal breaker for me because at significantly less than the competition I expect some compromises.
 
The AMS Neve, Calrec and Stagetech desks I use have digital limiters as do my pro tools and logic systems.

They all seem to work fine.
 
OzGizmo said:
If its a bad design to use digital limiters then most digital audio desks are then of a bad design.....
Please compare apples with apples, there is no point comparing a $1k recorder with a $6k recorder.
Click to expand...

Ha! OOOPS!
No - you added an extra zero. The DR680 mkII is six-HUNDRED dollars - not six-THOUSAND. So that makes it 40% CHEAPER than the Zoom.
Even Tascam's big dog the HS-P82 is only $2,400.

OK - why do we want Analog limiters on the front end when Digital ones on in the DAW computers and consoles are fine?
Answer: - TOTALLY DIFFERENT DEMANDS.
The digital limiters we use when mixing or doing post on a computer are going to be hit with signals YOU ALREADY CAN CONTROL.
Field Recorders get hit with the original UNPREDICTABLE sound source. And in the wild wild unpredictable live world analog limiters handle EXTREMES far more pleasantly that Digital ones do. I have MANY of both and I assure that this is a very real and accurate GENERALIZATION.
Sure, there are "some" digital limiters that are wonderful for live recordings - like the UAD Apollo - but that is a FULL Rack size unit that requires 120v AC-power and costs about THREE THOUSAND dollars. The AMS Neve, Calrec and Stagetech desks also have great front end limiters - and these wonderful desks are about as easy to attach to the front end of field recorder as a Volkswagen is.

When you severely engage a digital limiter of the type you will find on a sub-$10,000.00 field recorder the sound is destroyed either literally or functionally.
Analog limiters stand a FAR better chance of preserving "USEFUL" audio recordings when extremes are encountered.

...and they WILL be encountered.
 
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OK I take your point but I don't think I have ever considered if my limiter is digital or analogue, I have a panasonic HPX 371 camera and would not have a clue if the limiter is analogue or digital I just get the gain structure right and use it to make sure I don't get it too hot. In the old days of Nagra recorders we never used limiters at all but always seemed to be able to record OK.
 
Do the dr-680's really have analog limiter? You can pick them up on eBay for rather cheap, like cheaper than a new dr-70D.

But speaking of rather cheap I got a Sound Devices preamp on eBay that I was going to use in front of the Zoom F8 or a dr-70D it has analog limiter built in, transformers on both sides, and the preamp is super quiet. I got the mp-1 but there are others you can get for cheap like the mm-1 or the Shure FP-23 (made by sound devices). New they cost a lot like $400-$500 but used you can get them for like $99-$150 easy.
 
GaryNattrass said:
OK I take your point but I don't think I have ever considered if my limiter is digital or analogue, I have a panasonic HPX 371 camera and would not have a clue if the limiter is analogue or digital I just get the gain structure right and use it to make sure I don't get it too hot. In the old days of Nagra recorders we never used limiters at all but always seemed to be able to record OK.
Click to expand...

Digital VS analog is less important than where in the chain it is. Apparently the Zaxcom limiter is digital but designed with converters to behave as it should in a field recorder, which is to act as a safety valve for when a sound surprises you. Yes a LOT of devices have what they call limiters (some actually are) and most of them work very badly if at all. It's not uncommon to have a "limiter" on consumer gear act more like a AGC and have an audible recovery time with a response too slow to save the clip. My Marantz recorders "limiter" acts like that. You get the clip then a drop in volume and a slow ramp back up in volume. In short a total disaster.

The mix pre in contrast has a limiter that just keeps you from clipping and unless you are pounding the thing all you ever hear is a lack of clipping.

Analog tape, as in your old Nagra, is self limiting. Tape by it's nature will compress as it starts to saturate. You can eventually get it to clip but it's a soft clip compared to digital that eases into awfulness instead of just switching from fine to unusable. Also anything but really extreme analog clipping can be improved and in some cases eliminated in post because the signal is not obliterated by clipping as it is in digital clipping. So tape VS digital recording is a VERY Apples to Oranges thing.
 
"Digital VS analog is less important than where in the chain it is"... yeah, that was my original point. But it appears the F8's dynamic range and pres are good enough to mostly overcome this shortcoming. I just don't understand if this is a cost issue or design shortcoming...
 
I think it's probably a cost issue. And it could be a bonus since a firmware update might fix issues. It also looks like the design was pretty well thought out. The converters and analog input stages obviously are capable of taking quite a lot before they clip or the limiter wouldn't have performed as well as it did. Some tuning in the firmware may make the limiter perform as you would hope?
 
Huh? Maybe I'm missing something here?
How does a "limiter" in the DIGITAL domain AFTER the A/D converter do anything useful?
If the digitized signal CLIPS, then that means that the ANALOG signal going INTO the A/D converter is too hot.
The only remedy to that is to REDUCE ("limit") the signal in the ANALOG domain BEFORE it goes into the A/D converter.

If the digitized signal AFTER the A/D converter is NOT clipping, then why does it need "limiting"?
 
If Analogue v Digital Limiters a deal breaker for you may I suggest that you need to get better aquatinted with gear...... So what with 120+db of s/n do you have to run in the top 5% of maximum.... really?

Those of us that started with analogue recorders needed to learn a different level technique with digital.

So do you run all your RF mic systems on the point of limiting?
Do you drive your car reving to the red line of the Tacho?
Do you drive along the road at maximum allowable speed or do you drive to the road and weather conditions?
Do you cook your food on a stove with the cooking element on 'High'?

I did a 5 hr shoot the other day and I did even get the limit light of my SD442 to even have a dim glow.

If you are even getting to the point of using the limiters in 'general' recording may I suggest you are doing it wrong.
 
OzGizmo said:
If Analogue v Digital Limiters a deal breaker for you may I suggest that you need to get better aquatinted with gear...... So what with 120+db of s/n do you have to run in the top 5% of maximum.... really?

Those of us that started with analogue recorders needed to learn a different level technique with digital.

So do you run all your RF mic systems on the point of limiting?
Do you drive your car reving to the red line of the Tacho?
Do you drive along the road at maximum allowable speed or do you drive to the road and weather conditions?
Do you cook your food on a stove with the cooking element on 'High'?

I did a 5 hr shoot the other day and I did even get the limit light of my SD442 to even have a dim glow.

If you are even getting to the point of using the limiters in 'general' recording may I suggest you are doing it wrong.
Click to expand...


It's not for the everyday situation, it's for emergencies when you don't get a chance at another take. What if you are shooting a reality show and something real actually happens? You getting done of 12 hour workday with last shot to go and the audio guy screws up? What if your working with a impatient celebrity who does a mic check really low but starts talking really loud and yelling as soon as you start to record? It's for the times when you don't get a second take. But yeah if you can't set proper levels maybe you shouldn't be the one doing the sound recording.

Also with the F8 it would be kind of hard to ride the levels with those tiny knobs and using a iPad although cool requires another person or it could be rather wonky.
 
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Richard Crowley said:
Huh? Maybe I'm missing something here?
How does a "limiter" in the DIGITAL domain AFTER the A/D converter do anything useful?
If the digitized signal CLIPS, then that means that the ANALOG signal going INTO the A/D converter is too hot.
The only remedy to that is to REDUCE ("limit") the signal in the ANALOG domain BEFORE it goes into the A/D converter.

If the digitized signal AFTER the A/D converter is NOT clipping, then why does it need "limiting"?
Click to expand...

The answer would be in the over all design. If you use A/D converters that go past the range of your recorder then you can build in headroom you don't use except for those rare overs. In that case a digital limiter that works on that signal can keep the signal you record from clipping your recorder.

That is not so different from analog gear. A typical professional mixer could go +25 dB or so with out clipping. Analog tape started saturating at around 0dB but didn't get particularly nasty till much higher. Depending on where you set you final digital zero compared to your analog input you could leave yourself a fair amount of headroom. You could also build in headroom between what will clip your A/D Converter and that final zero.

This is I'm assuming basically what the F8 is doing since those maxed out signals were pretty decently dealt with by the limiter and there is no way that those were "repaired" digital clipping. They must be building in some digital headroom for the limiter to work with.

If that assumption is correct then it's fairly possible that the headroom might be adjustable with a firmware update that would make them act even closer to how great analog input limiters act.

It's always possible to overload no mater what protections are in place. I had a NAGRA (digital) recorder shutdown because the low end from a F-14 starting up caused a disk fault! That one may have altered my internal organs also... I never did get the low level supersonic fly bys to not distort. But for 99% of the time the need is for limiting something that just manages to surprise you and peak over the threshold. The F8 limiters seem like they are pretty well suited for that, not perfect but good.
 
All we all know (or should know) it is all down to gain structure and how each part of the signal chain is handling levels.

I would guess a lot of the time some people are actually overloading the mic end if they don't have -10db attenuators available but that could then be the mic pre-amp or onwards the digital side of things.

Limiters have their uses and are good in certain situations where the need to keep things under control are paramount.

Even with a Nagra and no limiters you could be caught out where the tape saturation and electronics could not handle a momentary peak.

Limiters can also be useful in broadcast or corporate production where you wish to always keep the levels legal or within the broadcast spec knowing that the editor or end user may have little control over the signal onwards. I use them all the time on live TV but they are there to keep things legal so are set to come in at around +6db PPM so that things never do go above max peak at +8db PPM (-10dbfs or -12dbfs USA)

As said a limiter after the A to D converter is no big deal for me and if you get your gain structure right at the front end it should be doing no more than keeping things from overloading later down the chain.
 
GaryNattrass said:
As said a limiter after the A to D converter is no big deal for me and if you get your gain structure right at the front end it should be doing no more than keeping things from overloading later down the chain.
Click to expand...
+11. It would prevent digital overflow but not protect the input stage, which could be over-driven regardless of the
digital level. Though the F8 input stage has a dual level control, one prior to the A/D, one post (sort of similar to some of the the old analog Tapco mixers which had no individual channel gain/trim pot. FYI, Greg Mackie was key to the Tapco product line)
 
Well the Zoom F8 is a affordable recorder and well worth the price to some. You can always put a nice mixer in the bag too like a 302.
 
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