I’ve been wanting to do this showdown between these two machines and their venerable converters and preamps for a couple of years. In this article which also has audio and video elements, I break down the sound, nature and usefulness of the preamps, Analog to Digital converters and what it all means for you between the Zoom F8 and H6 recorders. It’s the Zoom F8 vs. H6 Preamp SHOOTOUT! And it’s high noon.
What are Preamps? Well, in the audio world they are so many things to so many people. For us here, they are the “lens” that audio must pass through to be turned into a signal fitting of the “sensor” on the recorder. And just like on a camera, if you have a lousy lens and a bad sensor, it doesn’t matter how great your actors or light or set are, you’re going to get a noisy, colored, dim, low-contrast or just plain crummy image. It’s the same for audio. A preamp in a recorder boosts and colors the audio signal in such a way that the Analog to Digital Converters on the recorder (ADC) can turn the analog voltage into digital bits to be recorded. On the way out, the digital signal goes through a Digital to Analog Converter (DAC) and then goes out another kind of preamp. That preamp depends on what its feeding: if a line output, then it conforms the analog signal from the DAC to the right line voltage. If a headphone output, then it up-voltages the signal to be powerful enough to drive your headphones. You DO have a pair of Cinema Sound Headphones, right?
This clever combination of ADCs and preamps are the lens and digital sensor of your recorder, and the really are the most important aspects of any digital recording device in sum. They are SO important, that many of the top recording engineers lug around hundreds of pounds of racks filled with dozens of the preamps they know and love – and each channel of those preamps can cost upwards of $5,000 each. They’ll have dozens to record an orchestra.
Well nobody in multimedia does, which is why most manufacturers of low budget recorders put the cheapest preamps and ADCs on their units they can. They figure that no one will notice how noisy they all are and how badly they color the sound. Most people have no idea that the H series recorders from Zoom have a completely different set of preamps and ADCs from the F series. Who cares? Well, I’m going to say you should if you’re doing any kind of intimate dialog or music recording – to say nothing of recording room tone or ambiences. As you’ll see with our tests below, you may be upgrading your recorder after this article.
We took both the Zoom F8 and Zoom H6 and connected XLR cables to the first two channels of their inputs. Then recorded line noise from pots all the way down (in the H6’s case pots at about #2 – which is the lowest setting where audio can get through. A full-off setting is actual infinite attenuation), pots at 12 o’clock and pots full.
We then recorded music at +5 decibels according the the units’ meters to see how they handled distortion and “over zero” levels.
We then recorded two different tracks of music: one which had strong full-bandwidth audio with transients near zero dB, and another which was much smoother and had few transients but lots of sustained sounds. We recorded these at the same pot positions as the line noise and compensated for level by changing the output to the units from our audio interface. Thus, with pots all the way down we drove the inputs as hard as we could, and with the pots all the way up we drove them the least.
Naturally, with any preamp/ADC combination, turning up the pots all the way renders seriously noisy results, and it’s no different here. Part of the reason I wanted to do this test was due to the fact that I’d always discovered weird artifacts in the H6 preamps even at levels above #5. We would soon find out if I was just losing my mind.
All recordings – except the text .mp3 in the H6 – were done at 96 Khz/24bit.
We threw out the idea of recording dialog on a mic, since the self-noise of the microphone would add far more color to the sound of the recorders than we wanted. Plus, full-bandwidth music, we reasoned, would push the recorders to their limits faster.
There is really little reason to discuss the distortion test. Both machines recorded +5 decibels with such clarity that it almost didn’t sound like the recordings had gone over. You can clearly hear the quality difference between the units in the bass response distortion handling, but it’s so slight you’d miss it otherwise. The main reason for this is more because the H6 meters are really lying about themselves. The unit only really distorts when the record arm lights flicker. Even when the meter goes over zero, you’re still under. The F8 has about a 1 dB headroom above its noted zero – but its cleaner preamps seem to handle the lesser headroom well. Bottom line: both units handle overs like champs. But still, don’t do it.
I encourage you to watch the accompanying video on our Youtube channel to really get the gist of how these audio examples work together. But the noise these preamps create, when pots are even turned past 12 o-clock, is really noticeable. In the case of the H6, it’s laughable. Not only is there broadband white noise but a clever couple of whines in there as well. They are clear as day on any spectrogram and anyone on the street can hear them. For both of these units we want to drive them as HARD as we can to bring those sounds down. It’s clear that Zoom cut some corners to get these babies under a price point, and they cut many of those corners in the most important part of the recorder: preamps and ADCs. Boo.
Still, as will be heard in a moment, the F8s preamps have about a 5 decibel lower noise floor, and, of course, have no crazy whines or tones…although there is a noticeably larger bass rumble in the F8’s noise.
Music Test #1
For the “louder music” test, it is difficult to hear a difference between the units. Naturally, with the pots turned all the way up, the tell-tale sound of each unit’s self-noise sets them apart, but with loud, transient content, both units do well even at the 12 o-clock setting. Anything beyond that, however, and you’ll be sorry.
There is a definite sense, however, that the H6 has a digital “edginess” and perhaps a 4.5-6k bump. It wasn’t revealed to us until we compared waveforms between the units and the original musical file. There we saw about double the waveform deviations in the H6 than were present in the F8 recordings. Most of those artifacts were subtle, but they lived in that upper high and lower mid frequency zones. Which confirmed our aural findings; the H6 is a harsher sounding recorder.
Music Test #2
The real test of pudding comes with long, sustained tones at a mid-recording-level. We used the same preamp levels, but instead of driving the meters, we left the recording around -12 RMS. The program material’s lack of transients made for a smooth easy recording. Here is where the monsters were hiding under the bed.
For the F8, it was much the same as with music test #1. But for the H6, the artifacting on the mid pot and high pot recordings would have rendered the recorded music unusable: tons of artifacts on fades, high frequency edginess and enough noise to mask any kind of clarity. The lack of quality preamps and ADCs on the H6 rendered it a barely passable pro-sumer recorder in our books moving forward.
If you’re going to be driving the unit hard with pots below 12 o’clock, you probably won’t notice the H6’s inadequacies. But if you’re doing any kind of full-bandwidth, sensitive, dynamic recordings, this unit should not be used at all.
The F8, although it suffered its own noisiness and issues, given its price point of under $1,000, is more than passable as long as preamps are turned no further than 12 0’clock. Add to that it’s 8 channel and timecode capacity; it’s a good unit for general recording and far better than the H6 – from a strictly sonic quality consideration.
I’m horrified at the amount of recordings I’ve done with an H6 without realizing how bad the Zoom H-series preamps are. That’s right. It’s not just the H6 that’s the issue: it’s all H-series Zoom products. Even. Your. H4n.
So, maybe now is the time to upgrade? Perhaps so. Let me reiterate: if you’re doing highly transient recording: even regular dialog recorded strongly onto the meters of an H6, you’re probably going to be fine. And you’re certainly going to be better off than recording it to your phone or camera. Just note that the F series preamps and ADCs are superior to the H series…and there’s a reason why they’re more expensive.\