Shooting interviews: a better mic or a decent preamp?

[Phil Hendren]

I would really appreciate some input and help with making a decision concerning where my next $400 to $500 should go for enhancing the audio in my video interviews. Here is the situation:

I'm doing a number of single person interviews and I already own the following three mics:

AT8035 Shotgun
AT803 wired lav
Sony ECM44B wired lav

I've got them running via an Azden FMX-42 field mixer. This setup works very well with the AT8035 shotgun (boomed with overhead stand) and it also works ok with the AT803 mic (although the signal is a bit weak/quiet - even with the gain turned up on the Azden). The Sony lav by comparison is extremely weak (about 70% as good as the AT803 lav). I've played with settings and verified my configuration with Azden support and it all seems to be setup correctly.

The interviews I'm doing are going to be stationary with the talent seated indoors in a quiet room. Now I know I'm better off using a hypercardioid mic being inside, so I'm trying to decide if my best bet now would be to buy a mic like the AKG Blue Line SE300B/CK93 Hypercardioid and use that for my indoor interviews? Would the performance in my situation be comparable to the AT8035 shotgun (or do you think the gain issues will creep up again)?

-or-

Should I spend the money to buy a decent quality/small portable preamp such as the Sound Devices mm-1 and just use the Lav mics I already own (do you think that would work)? I don't mind spending another $500, but I've already spent something like $80 on a preamp marketed for musicians which introduced way too much noise/hiss (although the signal was nice and strong) and I also feel like perhaps the mic purchases I made weren't the smartest, at least as far as the lav mics (maybe I should have bought one better quality Lav mic instead of two less expensive mics?).

I'm going back and forth on this again and again, so any help you can offer would be much appreciated! Thanks.

[Steve House]

The rated output sensitivity of the 803b lav is 7dB lower than the sensitivity for the 8035 shotgun so it's not surprising you see that level difference. The Sony is in between, with a rated output of 10mV compared to 5.6mV for the AT lav. It should be hotter, not weaker, so something is fishy there. In order of sensitivity rating, the 8035 outputs -38dB (12.5mV), the ECM44 -40dB (10mV), and the 803b -45dB (5.6mV). Maybe the battery is dying on your Sony. The FM-42 has two mic sensitivity settings (-30dB and -50dB) - have you tried the -50 setting with the lavs?

The sensitivity of the AKG Blueline hyper is rated at -40dB (10mV) so I would expect it to be weaker than the AT shogun but hotter than the At lav. But then again, that's what I expect to see with the Sony lav as well. In fact, they should be the same.

Your shotgun is more suited to outdoors use where there needs to be a longer mic to subject distance. You should get an improvment in quality - less distortion from room reflections intruding - with the Blueline hyper you're considering but remember, location is the most important factor and it'll need to be close to the subjects to sound right - 20 inches or so from them. Precise aim is also important - a hyper on a static boom is fine to cover one person but the interviewer will be too far off mic to sound good (and that's true in spades for the shotgun). You need to mic the subject and interviewer separately regardless.

The MM1 is a good product but it is a mono preamp only - since you need two mics live, you need two of them if you go that route. It might be time to bite the bullet and go for a MixPre or a 302 mixer. Putting a preamp between the mic and your existing mixer seems redundent and a false economy - if the mixer's own preamps aren't up to par, get a better mixer.

I'm generally not a big fan of Azden products but I suspect the first source of the problems you're having is not the hardware but rather the mic placment. Make sure the lavs have fresh batteries installed. Position them in the middle of the talent's chests - have them clinch a fist and lay it on their chest with the knuckle of their thumb in the sternal notch at the base of their throat, just touching the bottom of the Adams Apple. Pin the mic capsule where their pinky falls on the button line. DO NOT pan the two lavs to the centre in the mixer, keep them separate and isolated with one panned fully to the left channel and the other panned fully to the right. Mixing and centering belongs in post, not the field.

For indoors seated interviews my first choice would be a boomed hyper on the subject, with a lav on the interviewer, and record them to two separate tracks using a proper mixer with good preamps. Second choice would be a lav on each.

[Phil Hendren]

Wow, Thanks for the reply Steve! I really appreciate it, it was extremely helpful. To answer your question: I have tried the Azden -30dB and -50dB settings for the lav mics, and the Sony's signal is still weak no matter what I do. After your reply and my repeated testing, I'm really thinking I might have just got a dud on that one (I've tried different brand-new batteries, better placement, etc). That particular Sony mic seems to have great reviews so I'm betting I just got a defective unit...

I hear you loud and clear on buying a different mixer (like the Mixpre or 302 - both seem great and I will do that if I have to). However I don't have any XLR inputs on my camcorder at the moment, so part of the reason I selected the Azden is that it had the 3.5mm output, so I could skip the XLR adapter. If I buy a Mixpre now, I'd have to pick up a juicedlink or beachtek adapter in addition. I might just end up going that route and being done with it, but I have one more question on this topic.

Perhaps you or someone else could suggest a higher quality lav mic or hypercardioid mic like the Blue Line I mentioned, one which would be as "hot" or even "hotter" than the AT8035 shotgun mic (as that AT8035 works perfectly with the Azden - really the AT803b isn't that bad either but you have to speak up, and for the potentially emotional interviews I'm doing I don't want to be continually asking the interviewees to speak up)? Now I'd be willing to drop some coin for higher quality mics if that would help, and that way I wouldn't have to replace the Azden right away (I've only had it for about 2 months now). Any suggestions on a mic which would meet this requirement?

Thanks again!

[Steve House]

I hear you loud and clear on buying a different mixer (like the Mixpre or 302 - both seem great and I will do that if I have to). However I don't have any XLR inputs on my camcorder at the moment, so part of the reason I selected the Azden is that it had the 3.5mm output, so I could skip the XLR adapter. If I buy a Mixpre now, I'd have to pick up a juicedlink or beachtek adapter in addition. I might just end up going that route and being done with it, but I have one more question on this topic.

I have one of these cables to handle that situation ... DV Cam Stereo Input Cable - DV Cam Cables - Cables, Connectors & Adapters - Trew Audio ... If the mixer is able to output a mic level signal that's all you need, no Beachtek or Juicedlink required. Accoding to the manual, the Azden is switchable between line and mic outputs.

The AT8035 is a reasonably hot mic so if you're having level problems using it I can't help thinking the problem lies somewhere besides the mic's sensitivity per se. If you keep having to ask the subject to speak up even with the shotgun mic, I suspect it's either mic placement or the way you have the mixer set up. Where are you putting the mic and EXACTLY how do you aim it? It should be above and in front of the subject, just out of shot, about 24-36 inches from his mouth, and pointed into an imaginary circle drawn around the his throat that's about 6 inches in radius. If you're okay there, where are you monitoring and judging the levels, the camera's meters or the mixer's meters? Or are you trying to judge levels by ear in headphones (connected where, to the camera or the mixer?) Exactly how do you set up the mixer, align it to the camera, and set your levels?

[Phil Hendren]

Hi Steve,

Sorry if I wasn't clear on what I was trying to ask. The AT8035 Shotgun works great with the Azden, no complaints there. I set it up via an overhead stand and the sound is great (It's prob 12-18 inches away from interviewee - mounted above but not facing straight down, out in front of them and with the cap facing in towards their head/neck just slightly). The Azden setup is also working very well when connected to the 3.5mm mic input on my camcorder (switched to the -36dBu).

I'm happy with my AT8035 Shotgun and my Azden but not happy with my current Lav mics. So can you help recommend a lav mic or a hypercardioid mic which would be as hot as my AT8035 Shotgun to add to my audio kit? As I think that would solve all my audio woes (and give me some mic options to work with).

Thanks!

[Steve House]

Well, the lavs you have are roughly in the same ballpark as your 'gun and the AKG Blueline is too. There's something else going on and until you solve it, switching mics isn't the solution to the level issues with the lavs. The 'gun isn't optimal indoors and a hyper sounds better but that's not level related. With the AKG Blueline rated at -40dB, that's pretty darn close to your AT shotgun.

[Bill Davis]

I'll bet you a nickel that you don't have your phantom power configured properly.

You'll get a signal from an electret wired lav (like the ECM-44) without it - but that signal will be conspicuously weak.

Double check your mixer input controls. And if you're unsure that the mixer is properly providing phantom, try a battery in the 44's internal battery holder. (unscrew the silver XLR housing - there's a slot for a single AA inside)

Let us know.

[Gabor Heeres]

For interviews and soundbites I'm using the Elektro-Voice RE-50. Still one of the best on the market in my opinion.

[Phil Hendren]

Ok thanks for that extra info Steve! I was having problems finding the sensitivity specs for my mics as I was checking the B&H website and it seems to be absent in many cases (I found other websites that give the info tho).

Originally Posted by Bill Davis

I'll bet you a nickel that you don't have your phantom power configured properly. You'll get a signal from an electret wired lav (like the ECM-44) without it - but that signal will be conspicuously weak. Let us know.

Thanks for the reply Bill. I'm currently using a new battery with the mic as it's power source and I did try swapping it for another different new battery but still the same performance... I've got the ECM-44B model and it looks like it isn't compatible with phantom power, so I've just been sticking with the battery power instead (haven't tried phantom power for any of my mics yet).

Maybe I'm just expecting too much from the lav mics? How loud do you normally have to speak to get a good signal with a lav mic like this? As they do work ok if I speak-up, but I have to speak like I'm talking to someone who is sitting 7 to 10 feet away, instead of being able to use my 12 inch voice. Perhaps that is just the way it is with Lav mics?

Thanks for the recommendation on the Elektro-Voice RE-50 Gabor, I'll check that mic out. Do you use it as a handheld? Or can you boom it?

[Steve House]

RE-50 would be a handheld, with the mic capsule within about 6 inches of the subject's mouth. And its rated output is 2mV/Pa, or -54dB, much lower than your mics.

The lavs should deliver normal levels with a normal conversational speaking voice. I can't shake the suspicion that something is wrong in your setup and calibration procedure for the mixer. Where in the signal chain are you actually discovering that the levels are too low ... in the meter readings on the mixer while rolling, aurally in headphones plugged into the mixer, meter readings on the camera, aurally in headphones monitoring in the camera while rolling, listening on headphones to playback in the camera, or playback on the workstation when editing in post?

I haven't used the particular mixer so a couple of pieces of info, if you please, if you'd like me to help you debug your setup procedure. One, does its master output have a detent around the centre of its travel marking unity gain? And, if you engage tone, is the level that is sent out constant on the meters and in the output regardless of the position of the master output level knob? In other words, if you engage tone and turn the master output knob up and down, does the meter indication go up and down in sync or does it remain steady pointing to zero VU? How about the level you see on the camera meters when you're sending tone and rotate the mixer's master output level - does it remain constant or go up and down?

[Battle Vaughan]

Phil, fwiw, I have the same Azden mixer and (while I and others throw rocks at Azden's lowball line) I find their pro line stuff actually pretty nice. I get a lot of headroom with a variety of mikes -- AT8035, Sennheiser ME66K6, several M-Audio vocal mikes, and a couple of MXL studio mikes. Unless there's something wrong with it, the gain that is available has been more than sufficient in my experience. It is a nicely made and very usable piece of gear, if they called it anything but Azden people would love it...my two cents.../ Battle Vaughan

[Phil Hendren]

Originally Posted by Steve House

I can't shake the suspicion that something is wrong in your setup and calibration procedure for the mixer. Where in the signal chain are you actually discovering that the levels are too low ... in the meter readings on the mixer while rolling, aurally in headphones plugged into the mixer, meter readings on the camera, aurally in headphones monitoring in the camera while rolling, listening on headphones to playback in the camera, or playback on the workstation when editing in post?

The levels appear too low at the mixer when using the Lav mics. The vu meters on the Azden stay in the sweet spot when using my shotgun mic, but when using the Lav mics they aren't hitting the sweet spot unless I raise my voice (like I'm talking to someone 7 to 10 feet away). Monitoring on the headphones at the mixer sounds ok (shotgun louder than the lavs). For the camera when listening via the camera headphones it sounds just like when listening via the mixer (shotgun sounds good, lavs quieter). Later when viewing on the PC you can tell the lav mics are much quieter - the Sony especially and the AT Shotgun sounds great. When I use the calibration tone it registers properly on the vu meters on the Azden and I use the master on the mixer to adjust until the vu meters are reading at 0db (adjusting the master one way or the other is reflected in the vu meters). Then I go to the camera and the tone registers nicely on the cam as well, where I adjust until the tone is kissing the red on the camera's meter (-20db is the setting I usually have it set at). After the calibration I only adjust via the mixer.

When I record something and play it back on the PC the sound is great with the shotgun, quieter with the AT803 lav mic (I can hear it ok but it's not nearly as clear as the shotgun) and with the Sony it is quieter than the AT803 lav (to the point where I'd say unacceptable).

To me it seems the Sony is just bad (defective or broken) and the AT803 lav is probably working correctly but it is just not as "hot" as the shotgun (which seems in line with the specs you had quoted).

Thanks again!

[Steve House]

Sounds like the basic setup between the mixer and your camera is fine. I'm just really perplexed at the weak signal from the lavs on the mixer meter. There should be more than enough gain on the individual channel preamps to drive the mixer to full output, even to peg the meters on the right side of the scale if you turn the fader all the way up. Are you opening the individual channel gain faders far enough? Try this -- working with one mic at a time, plug a mic into channel 1, for the Audio Technica turn phantom on while for the Sony turn phantom off. Using tone, turn the faders down all the way and use the master level to align the meters to 0VU. Leave the master level set at that point for the remainder of the test. Tone off. Start with the channel input switch sensitivity (under the input XLR connector) set to -30. Leaving the master level alone, while speaking normally into the mic turn up the channel fader and see if you can find a position for it where normal speech causes the meters to read between 0 and +4. Switch the sensitivity to -50 and repeat. One of the two switch settings should let you find a channel fader setting that gives a proper VU reading on normal speech. Repeat the tests for the other lav. That will tell you two things - one, whether the mics are okay, and two, what is the normal operating setting for the mixer with that particular mic. If you can find fader positions that gives you 0VU readings with both settings on the sensitivity switch, you want to use the switch setting that puts the fader the closest to the middle of its range. If there's no fader position that gives normal recording level, 0 to +4 VU, meter readings, then there might be a problem with either the mic or the mixer and we'll need to look further.

[Jay Massengill]

Also try switching your mic cables if you haven't already done so. Since you're using battery power for the Sony, a problem with a mic cable wouldn't necessarily prevent you from getting a signal, but it could cut the level in half. If you're using phantom power with a bad cable, that would be a noticeable problem right away.
If all your cables are the same brand and purchased at the same time, test them to make sure they are actually wired correctly. Improper wiring at the factory or broken or shorted cables do happen and as I said a problem wouldn't necessarily kill the whole signal just make it lower.

[Steve House]

Good points, Jay. I'm of the opinion that a basic cable tester like Berhinger's is a fundamental part of the kit. You can get by with a multimeter but the cable tester is so much more convenient and not at all expensive.