Does the H4 or H4N require a mixer?

[Chamber005]

So CV2 and I have been PMing back and fourth and he's been helping me loads with my trying to assemble an audio bundle for my webseries.

What I had been using was just a mess of hissing (Behringer mixers primarily for phantom power in conjunction with an old DSR200 with XLR inputs).

I've been going back and fourth with CV2 whether or not a mixer is required for some no-budget webserial stuff.

The mics and their placement is solid. Just trying to avoid a NOTICABLE hiss like what I was getting on my old set-up.

So I'm just wanting to put it to a vote, trying to get a general consensus from people who use or have used the H4 and/or the H4N with and without a mixer.

This video was made using only its onboard mics and certainly sounds like it would be sufficient for what I'm doing. And I can only imagine having (better) microphones even closer to the talent would help.

http://www.vimeo.com/5352858

Thanks so much for your input! And lots of thanks to CV2 for all his input thus far!

 

[Alex H.]

I'll go ahead and say this publicly, then... yes. The pre-amps in both recorders are lackluster at best (useless, really). Worse in the original H4. So an external mixer must be used in order to bypass the internal pre-amps on the Zoom.

 

[Chamber005]

I'll go ahead and say this publicly, then... yes. The pre-amps in both recorders are lackluster at best (useless, really). Worse in the original H4. So an external mixer must be used in order to bypass the internal pre-amps on the Zoom.

LOL

I love how you came out like it's been this dirty little secret. Just airing the dirty laundry of the H4!!

And D'oh! It's C2V, not CV2...

Sorry!

I sent you a PM on this vid, though. I didn't find there to be anything really distracting about the ambient hiss in the video. Maybe I'm just not listening correctly...?

 

[Stephen Mick]

Maybe I'm just not listening correctly...?

Is there a correct way to listen to anything? I mean, you either hear it or you don't, right?

I can't seem to find the owner's manual for my ears.

 

[j1clark@ucsd.edu]

LOL

I love how you came out like it's been this dirty little secret. Just airing the dirty laundry of the H4!!

And D'oh! It's C2V, not CV2...

Sorry!

I sent you a PM on this vid, though. I didn't find there to be anything really distracting about the ambient hiss in the video. Maybe I'm just not listening correctly...?

As I understand it, audio people distinguish 'ambient' from 'noise floor' of an instrument. 'hiss' to me would mean 'noise floor', where as freeway traffic or other type sounds, other than the desired sound, is 'ambient' sound.

The 'noise floor' of an instrument is the lowest point at which the combined 'noise' in the instrument, in the sensor, in this case the microphone, just generate because of various reasons, temperature, random electron firings, for example, cause the 'signal' to be lost.

The 'signal' in this case is the microphone's response to the sound of the speaker, in the case of actors in front of the mic, or whatever is desired to be recorded for sound...

If one places the mic 20 feet away from the speaker, the recorded 'signal' will be low. If one turns up the gain to compensate for this low signal, not only is the signal 'boosted' but also the 'noise', hence one hears 'hiss'.

Example tune your radio to a frequency which doesn't have a local transmitter, turn up the volume... hiss is the result... if a distant radio station is transmitting, the hiss and the radio signal combine into something that may be intellegible, but definitely the hiss is a dominant element of the sound coming from the speakers.

The same principle is true for the Mic + Speaker-at-a-distance. Or Mic+Speaker-speaking-very-softly.

Some electronics are designed to minimize the noise, and of course, there are costs involved, so, a product designer will make some form of decision about how much 'good stuf' vs. 'how much cost' the product will have.

In another thread a Sound Devices MixPre was recommended as a 'pre amplifier' for going in to the Zoom H4/H4N. As I recall the Zoom is about $400 new, and a check on the web shows that the MixPre is about $700. Furthermore all the MixPre does is amplify sound, with some controls, and some monitoring circuitry for headphones, and a few other things...

So, are you a 'gambling' man? Do you want to bet that the Zoom H4/H4N has 'less' in the pre-amp section than the single function MixPre?

What do you do if you can't afford the Zoom + MixPre... find the arrangement of Mic to Subject, Zoom gain settings that minimize the 'hiss'... It may be that you have to put your mic 1-2 feet from a subject to get enough 'signal' such that the 'hiss' is far less noticeable than when the mic is even 5 or worse 10 feet away.

In addition to 'noise floor' the other attribute of an amplifier is the gain, and again engineering is a compromize. More gain with a mind for minimizing distortion, means more expense. So again the MixPre wins on that account over the Zoom.

------------------------------
Just so we are clear, I don't do audio work, so I don't know what I'm talking about. So, take it for what it's worth.

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As for 'ambient' sound, that combined with noise floor often leaves the 'signal', that is the actor's voice, down in the mud. Boosting the gain, will again boost all of noise floor and ambient sound, and most likely is not what is desired.

Again, getting close to the speaker will give better results, but in some circumstances, there just be no good way to deal with the combined noise sources.

You can as the audio people what is a 'good' level above the noise for recording voice. I recall some number like 20-30 dB (whatever units... ask them...) over the noise as a 'good' starting point.

And just simply getting the volume indicators to show 'close to 0 dBFS' (or any predetermined value) doesn't work, because as noted above, 'gain' affects noise as well as signal, and so you have to look at the difference between noise and the signal. Ask them how to figure that out... One way that occurs to me the unprofessional, is if the little LED indicators don't go any lower than -30 dB, that with no one speaking, there's no indication on the LEDs. When someone speaks, esimate the 'max' indication on the LEDs and get it to -10 dB... I think you may have at least 20-30 dB of signal to work with.

The problem with noise and voice is also due to the fact that speach utterances use not only 'sound', but the absence of sound (like gaps between words, momentary gaps between sylables, etc.) and that's when 'noise' sneaks in to muck up the works.

But don't work, perhpas someone will jump in to correct my ignorance, and actually give useful information.

 

[Alex H.]

I love how you came out like it's been this dirty little secret. Just airing the dirty laundry of the H4!!

Not really what I meant... just saying I'd go ahead and jump right in, carrying on from the PMs. rogar-BigGrin(DBG)

 

[Alex H.]

This video was made using only its onboard mics and certainly sounds like it would be sufficient for what I'm doing. And I can only imagine having (better) microphones even closer to the talent would help.

http://www.vimeo.com/5352858

The dialog in the opening scene is very roomy, and with the wide framing on the two-shot, he either had to have it planted in front of the woman, or looped from an alternate take. The close-ups are close enough to get the H4 in to a workable distance, though there's still lots of room noise in there (which isn't necessarily a good thing).

Not a lot of dialog in this one, lots of VO. And must be lots of FX/Foley, because there are sounds in there that could not have been captured with the Zoom. The bulk of the sound in this film really is in ambience and FX. Not a great place to judge what you can or cannot do with the H4 in your situation.

This was a very creative use of the H4, but probably not practical for routine production. And he recorded at 44.1kHz, which is odd.

If you are shooting most/all your webisodes in the apartment, the H4's mics are going to let you down.

 

[TimTheFoolMan]

I'll go ahead and say this publicly, then... yes. The pre-amps in both recorders are lackluster at best (useless, really). Worse in the original H4. So an external mixer must be used in order to bypass the internal pre-amps on the Zoom.

I'm at a loss as to why adding a mixer to an H4n would improve anything, unless the 48v phantom power wasn't driving a mic with enough current. Adding any other device, no matter how clean, will degrade the signal. Are you certain that going into the 1/4" jacks is really bypassing the preamps, or are they just padded?

I've looked for, but not found, any actual schematics for this device. At this price point, I'm skeptical about them doing anything but padding the 1/4", but I'd love to know more. Even if they bypassed a portion of the preamp, the mixing function of the H4n suggests that you're just adding more to the signal chain. How is this helping? (I'm honestly asking here, and not trying to be snarky.)

If the H4n isn't clean enough, I would suggest using a Firewire mixer into laptop, or using a more "serious" recorder, rather than adding more hardware to something you're already not happy with.

It would be interesting for someone with a matched pair of mics to put some side-by-side recordings up. My guess is that the actual difference (again, assuming that there are no issues like insufficient phantom power), while possibly measurable, is most likely not audible.

As I've said in other threads concerning this device, I'm a noob, and maybe being 48 years-old has made me deaf to obvious differences, but I've not heard anything glaringly bad from the H4n, assuming the levels are set appropriately. - Tim

P.S. If you're noting the noise floor by monitoring through the headphone/line-out connector, that part of the system is widely accepted to be the weakest part of the unit. Comparing what you hear from that output to the recorded files (though most any other device) shows a huge difference.

 

[Chamber005]

Here's another one. The H4N with an AT4073a

The "hiss" I'm referring to is in the other two examples but is not present in the H4N w/ AT4073a clip.

I think it sounds completely serviceable...

http://www.vimeo.com/7670695

One thing C2V and I talked about as well was the HF200's onboard 1/8" jack and simply converting the XLRs.

Assuming that I went with JUST the H4N and not the H4 plus mixer (because of line in), what would sound better with a lav mic hooked up to it, an H4N or my HF200 cam's 1/8"?

Alternatively I suppose I could use my crappy Behringer mixer in conjunction with either one of these, but from what C2V has said the mixer is probably just as much the problem as the DSR200's audio capabilities are...

I'll upload a "behind the scenes" track from the original beta run of my series that has a bit of audio already synched to show you guys the audio in its raw form so that you can better hear what I'm trying to accomplish. Just give me a minute...

 

[Alex H.]

I'm at a loss as to why adding a mixer to an H4n would improve anything, unless the 48v phantom power wasn't driving a mic with enough current. Adding any other device, no matter how clean, will degrade the signal. Are you certain that going into the 1/4" jacks is really bypassing the preamps, or are they just padded?

On the original H4: there is a LINE setting for the 1/4" in. The pre-amps are terribly noisy.
On the H4N: there is no LINE option anywhere for the 1/4" in. The pre-amps are improved, but still not pristine.

A pre-amp serves one purpose: to bring mic-level signals (-58dB... can be higher, can be lower) up to line level (+4dB or -10dB) for proper recording. If the signal coming in is low, the pre-amp has lots of amplification to acheive (usually by manually raising the gain)... which also amplifies any noise that the pre-amp has introduced. If the signal is stronger, the pre-amp has less work to do and thus does not amplify any noise of its own. Even if the line-level signal coming in is merely padded, as is the case with many cameras' XLR ins as well, it means that the pre-amp doesn't work as hard.

No, the headphone circuits in these recorders, as with many cameras, cannot be trusted since they also are noisy. And that noise will not be present on playback through a proper system. But noise introduced by the pre-amps will be there in the recording.

And adding a mixer isn't going to kill the signal... especially if it has good, clean pre-amps and sends a solid signal to the recorder. It's not even going to make any difference for the worse (quite the opposite). If adding a mixer (a good mixer) degrades the signal, why is it a pretty standard signal chain in production to have a mixer that feeds either camera, recorder, or both? A good mixer is a crucial tool in good audio production. (As has been said many times, it's more the user than the tool... but having the right tools helps.)

And a USB/Firewire interface into a laptop may be a better choice, but only if the interface has good pre-amps or a production mixer is used to send line-level ins. For instance, I'd never recommend a Lexicon Lambda for its pre-amps. But for line-level ins from external mixer or pre-amps, it's just fine. Though a laptop and interface, or a higher-end recorder, may be a much better choice... we are talking about budget here. Those two options can be much more expensive, and the laptop option is only viable if there's not much movement (i.e. on a sound cart). Even at that, most big-budget carts that run laptop recording with interfaces also have mixers that feed those interfaces.

 

[TimTheFoolMan]

A pre-amp serves one purpose: to bring mic-level signals (-58dB... can be higher, can be lower) up to line level (+4dB or -10dB) for proper recording. If the signal coming in is low, the pre-amp has lots of amplification to acheive (usually by manually raising the gain)... which also amplifies any noise that the pre-amp has introduced. If the signal is stronger, the pre-amp has less work to do and thus does not amplify any noise of its own. Even if the line-level signal coming in is merely padded, as is the case with many cameras' XLR ins as well, it means that the pre-amp doesn't work as hard.

If you've seen this in the field, then I stand corrected. From an electronic perspective, this makes no sense to me, and this is coming from someone who spent a couple of years designing discrete differential amplifiers for the electronic weighing industry, where the signals we were resolving were in the 3.5 nV range.

I understand what you're saying... I just disagree about electronic amplfication working this way. As I said though, if you've seen actual field results to validate this approach, then I stand corrected (and will obviously have to do some further study on the actual circuits). - Tim

 

[Alex H.]

If you've seen this in the field, then I stand corrected. From an electronic perspective, this makes no sense to me, and this is coming from someone who spent a couple of years designing discrete differential amplifiers for the electronic weighing industry, where the signals we were resolving were in the 3.5 nV range.

I understand what you're saying... I just disagree about electronic amplfication working this way. As I said though, if you've seen actual field results to validate this approach, then I stand corrected (and will obviously have to do some further study on the actual circuits). - Tim

I have seen this in the field. And in the studio. And on the live stage.

Even some of the better pre-amps still have a noise floor, and the more you have to crank up the input gain, the more noise is introduced. Some pre-amps don't have any noticeable self-noise until they're pushed past 75%. Some not until they're wide open. The best have barely-noticeable (if any) self-noise wide open. But no matter what you have, this is where proper gain staging is crucial... at each point in the signal chain where gain can be adjusted, set it to pass on the best signal-to-noise ratio so that it doesn't add too much self-noise.

 

[TimTheFoolMan]

My experience has been much more like what Ted Spencer describes here:

http://www.dvxuser.com/V6/showpost.php?p=1826015&postcount=42

Is there something really obvious that I'm not getting? - Tim

 

[Alex H.]

It really depends on how each individual device is designed.

I know, from personal experience, that the mic pre-amps in the original H4 are noisy... and that using line in from a mixer solves the problem.

 

[j1clark@ucsd.edu]

If you've seen this in the field, then I stand corrected. From an electronic perspective, this makes no sense to me, and this is coming from someone who spent a couple of years designing discrete differential amplifiers for the electronic weighing industry, where the signals we were resolving were in the 3.5 nV range.

I understand what you're saying... I just disagree about electronic amplfication working this way. As I said though, if you've seen actual field results to validate this approach, then I stand corrected (and will obviously have to do some further study on the actual circuits). - Tim

If you were using some sort of strain gauge or the like, you were measuring a DC voltage, and so would roll off frequencies higher than say 10 Hz. So, you would not 'see' such a signal amplified, unless your circuit was sitting near a RF transmitter, and your common mode rejection was insufficient to eliminate it.

At the very least you have thermal noise which is dependent on the the resistence of the sensor, temperature and 'bandwidth' of interest, which in the case of DC measurements is narrow, like the 10 Hz above, but not vanishing... at least in 'real' circuits...

In the case of audio circuits the bandwith is larger, hence there is more thermal noise at the very least.

In the case of such a device as the Zoom, one has digital and analog circuits in close proximity, and often there can be 'pick up', even if the designer keeps the analog and digital grounds separate and the analog sections shielded. Back in the olden days of my analog DC designing, I would put a fake 'resistor' between 'digital ground' and 'analog ground', which in the final bill of materials would be replaced with a heavy gauge buss wire, just so the 'layout' person would not 'optimize' grounds and have analog and digital grounds connected to any old place they saw fit...


But again I'll note I don't know anything about audio, so take that for what it's worth.

 

[TimTheFoolMan]

If you were using some sort of strain gauge or the like, you were measuring a DC voltage, and so would roll off frequencies higher than say 10 Hz. So, you would not 'see' such a signal amplified, unless your circuit was sitting near a RF transmitter, and your common mode rejection was insufficient to eliminate it.

That's exactly what we were doing... amplifying the differential DC voltage off load cells, and ignoring several volts worth of common-mode AC noise. The relevance to this discussion is my awareness of the various noise sources (primarily thermal and digital), which (in my experience) are multiplied by inserting additional devices in the signal path.

In the case of audio circuits the bandwith is larger, hence there is more thermal noise at the very least.

Exactly, which occurs in every device that I have ever seen, to varying degrees, regardless of quality. Surprisingly, the quality of the resistors in the front-end was almost as important as any other component, because of thermal noise and drift.

In the case of such a device as the Zoom, one has digital and analog circuits in close proximity, and often there can be 'pick up', even if the designer keeps the analog and digital grounds separate and the analog sections shielded. Back in the olden days of my analog DC designing, I would put a fake 'resistor' between 'digital ground' and 'analog ground', which in the final bill of materials would be replaced with a heavy gauge buss wire, just so the 'layout' person would not 'optimize' grounds and have analog and digital grounds connected to any old place they saw fit...

Understood. I saw virtually the same thing happen when I handed off a carefully designed discrete differential amp (built with matched, ultra-low noise transistors) to my boss, who immediately returned with complaints about the noise, all of which could be traced back to the micro, and effectively bypassing my efforts with multiple grounds.

But again I'll note I don't know anything about audio, so take that for what it's worth.

It sounds like you know enough.

There are situations where I definitely think a mixer or pre-amp would be beneficial to the Zoom, but this is primarily related longer cable runs in really noisy environments. If I've got a 50' XLR cable running from my mic to the H4n, I can definitely understand why it might be preferable to have a 10' XLR from the end of the boom to an over-the-shoulder mixer, and then sending a line-level signal 50' to the H4n.

Apart from this situation, or one in which the mixer is better suited to the characteristics of a given mic (more tolerant of a higher output, or a higher gain structure that can bring the level of a mic up to usable levels), I'm not understanding how the H4n's S/N is going to be effectively reduced by feeding it a larger signal, which it will pad down, and then amplify back up, bringing its noise (and the noise from the preceding mixer) along for the ride.

If you can add to, or elaborate on, what C2V is saying, maybe it will become clearer to me. - Tim

 

[j1clark@ucsd.edu]

Apart from this situation, or one in which the mixer is better suited to the characteristics of a given mic (more tolerant of a higher output, or a higher gain structure that can bring the level of a mic up to usable levels), I'm not understanding how the H4n's S/N is going to be effectively reduced by feeding it a larger signal, which it will pad down, and then amplify back up, bringing its noise (and the noise from the preceding mixer) along for the ride.

If you can add to, or elaborate on, what C2V is saying, maybe it will become clearer to me. - Tim

I think that's the point, by selecting 'line' input from another device, one avoids sending the signal through their pre-amp, which based on the coments of C2V, 'is not that good'...

So, given that I'm guessing, one is presenting to the digitizer a 'clean' line level, rather than a signal that has some noise contributed by the pre-amp in the Zoom.

 

[tflak]

Thought these comments on the quality of the H4n preamps were interesting - especially the 5th paragraph:

http://www.dvxuser.com/V6/showthread.php?p=1824593#post1824593

 

[Chamber005]

That's exactly what we were doing... amplifying the differential DC voltage off load cells, and ignoring several volts worth of common-mode AC noise. The relevance to this discussion is my awareness of the various noise sources (primarily thermal and digital), which (in my experience) are multiplied by inserting additional devices in the signal path.

Exactly, which occurs in every device that I have ever seen, to varying degrees, regardless of quality. Surprisingly, the quality of the resistors in the front-end was almost as important as any other component, because of thermal noise and drift.

Understood. I saw virtually the same thing happen when I handed off a carefully designed discrete differential amp (built with matched, ultra-low noise transistors) to my boss, who immediately returned with complaints about the noise, all of which could be traced back to the micro, and effectively bypassing my efforts with multiple grounds.

It sounds like you know enough.

There are situations where I definitely think a mixer or pre-amp would be beneficial to the Zoom, but this is primarily related longer cable runs in really noisy environments. If I've got a 50' XLR cable running from my mic to the H4n, I can definitely understand why it might be preferable to have a 10' XLR from the end of the boom to an over-the-shoulder mixer, and then sending a line-level signal 50' to the H4n.

Apart from this situation, or one in which the mixer is better suited to the characteristics of a given mic (more tolerant of a higher output, or a higher gain structure that can bring the level of a mic up to usable levels), I'm not understanding how the H4n's S/N is going to be effectively reduced by feeding it a larger signal, which it will pad down, and then amplify back up, bringing its noise (and the noise from the preceding mixer) along for the ride.

If you can add to, or elaborate on, what C2V is saying, maybe it will become clearer to me. - Tim

As far as the H4N is concerned C2V's perspective is that it isn't a good device with or without a mixer. He's told me the H4, however, is okay as a recording device because it's line in is not using the Zoom's preamps. Apparently you can't escape the H4N's preamps no matter what port you use.

My argument, I think, is not whether or not an H4N can benefit from a mixer (apparently it cannot because of the above mentioned), but is it sufficient on its own as a recorder for low budget webseries stuff. And, furthermore, is the H4N better than an XLR being converted to 1/8" and plugged directly into my HF200 camcorder (based on specs).

I don't really UNDERSTAND any of the specs in regards to audio, so that's what I'm hoping to learn regarding the H4N/H4 vs. my other options.

 

[Alex H.]

As far as the H4N is concerned C2V's perspective is that it isn't a good device with or without a mixer. He's told me the H4, however, is okay as a recording device because it's line in is not using the Zoom's preamps. Apparently you can't escape the H4N's preamps no matter what port you use.

I never said the H4N isn't a good device in any way. As a stereo field recorder, it is much more rugged in construction than its predecessor, and the stereo mics are better designed.

The pre-amps in the H4N are vastly improved over the useless pre-amps of the H4. I've heard some relatively good stuff come from them, but I would never assert that they are up to par with Sound Devices or the like.

So before I'm misrepresented again...

The original H4 is the better of the two as a double-system or backup recorder when a mixer is involved, as it is a fantastic recorder for line-level signals. And honestly, a mixer is an indispensable tool in audio form film/video/TV. I woudln't go out in the field with just a 2-channel recorder. Don't expect miracles out of the H4 if plugging mics in directly.

The H4N has some challenges in accepting line-level signals, but even with a padded line-level signal coming in (and attention to gain staging) it can be workable with a mixer, and that will still minimize any noise introduced from the pre-amps. It's a great handheld recorder for ambience/FX... probably better than the H4 in that respect.

Another thing to consider is the need for phantom power. This is a battery killer with both of these devices, and there have been some reports of folks experiencing noise/interference when using the DC power adapter.

The original question here is regarding the necessity of a mixer in order to use either of these recorders. And I stand by my assertion that a good mixer will improve performance here. And I'll also say again that I'd never run a handheld recorder as my primary audio device... unless, of course, I'm using the built-in stereo mics for ambience.