Need advice about how to compare mic specs

[Pedanes Bol]

Lawrence,

Here is a sample recording I made with AT825 attached directly to D5 MII. In this case the microphone and camera were about 6-8 ft away from the quartet. When I listen to the audio with a studio monitor headphone I cannot detect any hiss sound and I believe sensitivity is not an issue. (I am old, might not be hearing it).

AT825 Audio Sample

I am very satisfied with this microphone in my setting (which is very similar to what you want to do). With an XLR connection and JuicedLink preamp you may get even better audio. You may find a 25ft or 50ft 5-pin stereo XLR cable at B&H. You may attach the 5-pin to double 3-pin splitter which comes with AT825 to the extension cable at the JuicedLink end.

I think this is a great stereo microphone and since it is discontinued you can get a used one cheap.

I hope this helps, good luck.

[Richard Crowley]

Originally Posted by Lawrence W. Pry

And with the Audio Technica AT8022 we've come full circle.

It seems to fit the bill and everybody says nice things about it--though no one seems to have actually used it--but its frequency range tops out at 15k Hz. That's what gives me pause. Am I being unreasonable? Its predecessor, the AT825, shows a more complete frequency range, but its sensitivity is significantly lower.

Give us an example of anything out in the Real World for which you need 20KHz response?
I strongly suspect that the 15KHz is a much more realistic statement of how BOTH microphones perform.

If you are recording bats, then you need a special ultrasonic microphone anyway. Else I can't think of ANYTHING on this planet for which you really need 20KHz response.

IMHO, yes, you are being unreasonable. No offense intended, you asked. :-)

You will hear a MUCH BIGGER difference moving the same microphone 6 inches than you would between a microphone with a 20KHz spec vs. a mic with 15KHz spec.

[Brian David Melnyk]

While i agree that mic placement is critically important, i have to strongly disagree with this statement:

'I can't think of ANYTHING on this planet for which you really need 20KHz response.'

limiting your frequency range to 15Khz, especially for a string quartet, is like sticking a dirty sock on your mic. all of the subtle nuances and incalculable interactions between overtones and harmonics will be compromised. often adding a small boost in the higher frequencies will open up the sound considerably and add 'air'. if the frequencies aren't there, they aren't there. a bit like bits- would you rather color correct with 8 bits or 16?

[Paul R Johnson]

What has 'what you hear' got to do with what the people who listen to your material can hear. My hearing now I'm over 50 is completely gone at 17KHz - no amount of level is heard, but you try recording some 18-20KHz tones at full level on a CD, open the window and play it when young people are around. You can drive them mad!

I record all my audio projects at 48, or often 96KHz sampling rates, with 24 bit depth because I can - the intention is to record for those golden eared people who can hear the difference - the fact I can't benefit myself means nothing at all!

There is also plenty of evidence that indicates that the information in the upper range conveys additional information some people can detect. Indeed, the special tone that some instruments produce because they are quality/expensive is lost if you remove the overtones - and many of these are over the cut-off of individuals. However, nobody has a hard cutoff - hearing just gradually deteriorates with age. I can hear 16KHz pretty clearly, it gets quieter at 16.5KHz and is gone by 17! We're all different - but many musical instruments generate sound over 15KHz - even jangling a bunch of keys does this!

[Lawrence W. Pry]

The data I've seen indicate that several instrument--most notably cymbals, piccolos, and violins--all produce harmonic frequencies up to 16k Hz. The human voice apparently also produces "breath/air" frequencies up to 16k Hz. All things being equal, my assumption is that it's better to capture these frequencies than not. It seems to me that without these higher frequencies, the recording could sound flat or listless.

[Richard Crowley]

Of course, you are assuming that because the marketing prose SAYS "20KHz" the microphone actually has usable response all the way up there. You will find that the more honest microphone manufacturers have published specs that LOOK "worse" because they are honest.

Frankly, I don't think EITHER of those mics has anything resembling flat response out to 20KHz, but the "15KHz" spec is probably a more honest representation of what to expect in the Real World.

[Jon Fairhurst]

For compressed video (and audio) on the web, content above 16kHz isn't all that important. Analog TVs (NTSC) had rescan at 15,750, which was an audible (to some) squeal. Content above that frequency simply didn't matter.

Now, if you're recording for CD/SACD/DVD-A for music distribution, that's another story. Many listen to music closely in controlled environments. In my experience, I don't really "hear" the difference between 16-bit 44.1 kHz music and 24-bit 192 kHz music, but I find that the soundstage is much better defined with higher quality recordings. This matters for "sweet spot" listening, but not for FM radio in the car - or even for an audiophile system when in the kitchen doing dishes.

Keep in mind that the mic you list likely doesn't have a (non-fiscal) cliff at the cutoff. The specs don't show how many dB down the mics are at the cutoffs, so the "15 kHz" mic might have the superior high-end response with fewer resonance points and shallower dips.

My main two points are:
1) The importance of higher frequencies depends on the context, and
2) The 15 kHz spec doesn't tell the whole story.

[Lawrence W. Pry]

Thanks Jon. You're right, there is no "cliff" at the end of the frequency response graph. Here's a link to the graph:
AT8022 Frequency Response

[Jon Fairhurst]

In my experience, a boost around 2.4 kHz can give a voice or instrument more character (positive) or a more nasal (negative) sound. A boost from 5-15 kHz adds "air", but can also add noise. As long as a mic is relatively clean and uncolored in these regions, you can adjust to taste with EQ.

Regarding the string recording posted earlier, you can hear the (overly?) nasal tones of the viola clearly. The bump above 5 kHz keeps it from sounding muted. Even though the piece didn't include much space between notes, you can hear the noise (above your amplifier noise) by pausing and playing the file. It's not bad when the music is "full" (for online video), but could be a problem for a sparse piece and would definitely be a problem for ambient recordings.

Sound for picture is especially critical of noise. When recording dialog, there is space between words. When recording footsteps, a glass clinking, or a pencil writing on paper, there is often more space than sound. To make noisy recordings usable, one can apply noise reduction, but then things can sound distorted and "underwater".

So, while the violin piece is an example of a chamber work, I doubt that its representative of the breadth of recordings one would want for a woodwind ensemble and soundscapes.

[John Nantz]

Hi Lawrence - congratulations! You're up to 6 posts now. Sounds like "we" (DVinfo) might be a keeper??

Hey guys, this thread is really moving along on the frequency topic which is all well and good, really adds to the information, but there are a few questions that I still have:

1. "How will the resultant video be viewed or disseminated?" f.e., via DVD, YouTube, etc?

2. Cost-benefit or bang-for-the-buck: While perfection in this case would really be nice, and Lawrence did indicate he is heavily invested in photography gear (my kinda guy!), this is a new area he is getting into (i.e., video), and he did state some concerns about going overboard on budget (gotta keep the wife from getting P.Oed), there has to be some trade-offs. Where does one draw the line? What's good and good enough?

3. How will the video be edited? iMovie? FCPX, or something else? How long is it envisioned to be?

4. What are your/Lawrence's future video plans or aspirations? Are you being honest with us when you say you want to keep equipment costs down? Or is this just a ruse to keep the wife off-guard?

Lawrence, correct me if I'm wrong, but I'd think that some kind of compromise might be in order. You're doing this video stuff as a freebie and up till now they (the audience) hasn't got anything to see except for perhaps a few video clips here and there so almost anything you're trying to do will be a real step up from what they've had/seen previously.

For starters, based on what I've read, it SEEMS that Lawrence really does want to keep costs down. The reality, though, is he'll probably opt for some $200-300 budget mic for now and if things go according to how I think they will go, more and better mics will be added later an the SO will roll over on it to keep her man happy (assuming they're still a couple).

Solution: Get the show on the road! Forget the nuances (for now). Go buy the Rode Stereo Video mic, make some recordings, edit and distribute them, and see how it goes. We're here to serve (and help spend your bucks).

If everything goes well, and we hope it will, come back and ask what to upgrade to. In the meantime, you have a really good little mic for all the family point-and-shoot stuff. This will buy you some time to soften up the S.O. for what's to come later.

[Brian David Melnyk]

or a something like a zoom h4n... and maybe plural eyes. then you can walk around with headphones and find the sweet spot and also not have a 12 min time limit (i think you were going to record audio on DSLR?). you'd have to be pretty careful with levels as you likely would be too far to monitor/change them, but there is an on board compressor/limiter that would help out. recording with a mic to (most) DSLRs without a preamp, you wouldn't be able to even see the levels or change them when recording anyway...
i think the onboard mics sound pretty good, and you can always add more mics later for greater versatility ie: record with internal mics and external mics at different levels for safety, and also out to the DSLR.

[Lawrence W. Pry]

Thanks again to all, especially to John for such a kind welcome.

Like John, I agree that it is time to get the show on the road. To that end, I've bought an Audio Technica AT825 on ebay. I've read many good reviews of this mic and Pedanes's experience encouraged me to pull the trigger. I'll use it for a while and see what happens. Frankly, I'll be very surprised if it isn't suitable for my (humble) needs.

I do want to say a brief word in response to Brian's suggestion about the H4n. Actually, my most recent foray into DSLR video was using a rented H4n. I was quite happy with the sound and I found it fairly easy to use. I just started it and let it run throughout a 45-minute recital. Meanwhile, I had to start and stop the 5DII from time to time because of that 12-minute file limit. What a pain in the ass!! So, what's wrong with this setup? I still haven't been able to sync the audio and video. I'm using Premiere Elements (for the first time) and thus I can't use PluralEyes. If anyone knows another way to get this done, other than trial and error (which isn't working out so far), I'm open to suggestions. I decided that from now on I'm recording the audio with the video. End of story.

[Jon Fairhurst]

I sync manually, generally using Vegas Pro. I set the DSLR to AUTO volume when using an external recorder so I'm guaranteed of having a strong signal that doesn't clip badly. Here's my process:

1) Get things close by whatever means possible.
2) Zoom in and align the waveforms.
3) Listen to the camera and external audio together with somewhat balanced levels. Fine tune the alignment until I hear minimal echo.
4) Mute the camera audio.

Unless there are many, many cuts, I find that manual alignment is fast enough that I've never felt a need for an automatic solution.

[John Nantz]

Adding a Recorder? Sounds like gear collecting! This is what video is all about. Well, let me re-phrase that a bit. This is what one wants for doing video. I'm in a similar boat so to speak, and was also looking at getting a recorder because I didn't care for the cable issues. However, that has been put on hold for a bit while I work on more pressing issues that have risen to a higher level of importance.

My first choice started out being the H4n but since then the Tascam DR-40 is the one I'm using for a comparison standard because of its low noise. I haven't by any means finished making comparisons or reading user comments with other recorders, or even determined for sure if this is really what is needed. Just thought I'd throw this out there as something else to look at or consider.

With regard to mics, one thing to be really careful about is making sure what you're getting isn't counterfeit. Shure and Sennheiser are two popular brands that counterfeiters like to replicate and I'm sure that there are others. Anyway, being forewarned is being forearmed. With an eBay purchase make a screen shot of the ad before it's gone and if it is charged on a major card and turns out to be fraudulent, maybe you could be protected, I don't know. This worked for me once with a purchase of an OEM battery and they sent me a generic one instead but the card company did a go-between and reversed the charge. There are lots of fraudsters out there!

[Pedanes Bol]

I agree with Jon. Make sure you record H4N audio at 48kHz/16bit mode. This syncs well with D5MII audio.