PD170 Newbie with Audio Concerns

[Steve Gray]

I’ve played with my new PD170 all afternoon. My only concern at this point is the audio I am getting with the stock mic. I can only compare it to what I get from my TRV950. When comparing them with AGC on, the PD170 stinks. I know the mic is directional but I just don’t hear those sounds that are clear as a bell in the 950.

I played with it turning AGC on and off with the recording level from one end to the other. If I crank the recording level all the way up, my meter finally reaches 0 db on sounds that should blast you out. I am just not hearing what I should be hearing through my headphones.

I plugged in my wireless UHF to ch2 and it sounded awesome. I plan on doing allot more “testing” in the days to come but does this sound right? The sound is there just not at the level of my 950.

[Mike Rehmus]

The stock microphone is not very sensitive but it is OK close up. You will need a different microphone if you want high output and directional selectivity. A cardiod is my first choice, a shotgun is maybe my 3rd choice.

[Steve Gray]

Thanks Mike. I have an azden sgm-2x that works great on my 950. Most of what I do is outside with nature. As soon as I get a cable with the correct XLRs on both ends, I'm going to try it. Is there a particular cardiod that you recomend?

[David Ennis]

Steve, I'm wondering if the MIC/MIC ATT/LINE switch affects the on board mic on the PD170 and if you had it in the MIC ATT position. On the Canon GL2, MIC ATT affects both external and internal mic levels.

Anyway, you may be happy with the Azden for nature sounds. Give it a try before you buy another cam mounted mic.

[Steve Gray]

Fred, I made sure the switch wasn't on the Mic/Att setting. It picks up sound O.K. just not like the 950. I think the Azden will work fine. I just have to get or build the right cable.

Thanks,

[David Ennis]

Order today and you'll have it withing a few days. If you're anything like me, that's a lot faster than I'd ever get around to buidling it. And for $10...Hey.

http://www.bhphotovideo.com/bnh/cont...ughType=search

[Tim Polster]

Hi Steve.

I am a little underwhelmed with the PD-170 audio myself.

I hooked up a nice recording condenser and went and recorded a piano concert.

The PD-170's pre-amps could not handle the sound pressure from 2-3 feet away and clipped the entire time while I was monitoring the manual gain at safe levels.

I now use the ATT switch for everything or turn the pad on in my mic because the pre's are so sensitive to clipping.

The stiock mic (as with all stock mics) is rather poor. It has a shotgun type directionality which makes it a lesser choice for a lot of event/run & gun work.

Nice camera, but a little overhyped compared to a VX-2100 for $1000 less.

[Mike Rehmus]

Put one channel in Auto and run the other down to about 1/4 in manual. You will get everything and be able to achieve a larger dynamic range.

For critical recording, you should always use an outboard mixer and manage that, not the camera (which has hard to operate controls compared to a mixer).

Beyond that, I'd not use a 170 or 150 for any really critical recording. Does fine for movie dialog, etc. But compared to a high-quality, low-noise recording system, it is inferior. Not to say it isn't normally quite good enough.

[David Ennis]

Tim, it wasn't the cam's fault (unless it's actually defective). You've definitely fallen into two traps that trip up a lot of us, and possibly a third.

1. Your mic is too hot for the input without ATT. Not to sound sarcastic, but that's why mics and cams come with specs. So yes, the signal was being clipped at the input as you said.

2. The recording level meters give absolutely no indication of what's happening at the input. They only monitor the recordiing level so you don't get clipping at the A/D converter. So you were diligently recording the audio mess at the proper level.

3. So how do you detect clipping at the input? Headphones. Were you monitoring with headphones?

The PD170 specifies -60 dBu (-62 dB) nominal for mic inputs. i.e., a mic operating at -62 dB output should work fine with the cam's gain controls mid range with no MIC ATT. MIC ATT on the GL2 is 20 dB. I assume that's standard. So with MIC ATT, the PD170 would expect a -42 dB signal.

Mics are usually spec'd at their output for 94 dB (1 Pascal) of sound pressure. That's about the level of a lawnmower a meter away--difficult to shout over. Mic output is roughly linear with sound pressure. You have to estimate, or consult charts. If the mic was a few feet from the piano it could easily have been getting pressure peaks above 94 dB in my estimation.

[Tim Polster]

All good points about audio recording.

I agree mixers, preamps etc... should be used, but 'always' is a tough word when budget and space issues come into play.

The reason I am not so crazy about this camera's audio is that it is billed as a "professional" camera.

I should be able to plug a professional mic into it and not have to dumb it down so it doesn't overblow the pre amps.

I use the piano recording as an example because when I listened to the audio from the PD-170, I took the same mic and plugged it into my Firepod & laptop and could not get the signal to clip from input, even when I put the mic an inch away from the hammers.

The point of my post is that I guess what I expected from a camera deemed to be professional was not met.

The monitoring was my fault, but the overly sensitive preamps are the camera's fault.

By the way, I think the ATT switch tends to lower the input to an extreme, to the point that one needs to turn the preamps up to a very high point to get a decent level.

When I shoot with this camera, I know I will need to process the audio to raise the volume because I need to record at such conservative levels.

Like I said, it is a nice camera, but I wonder if buying the VX-2100 and a Beachtek would yield some better audio results?

[David Ennis]

I could name some other pro cameras that couldn't handle particular pro mics without attenuation according to reports here, but that would really take this thread off on a side trip. Start a new thread if you'd like to discuss it more.

[Steve Gray]

I took both cameras, the PD170 and my TRV950 to the wood this morning and had a little audio test session. I tried about every combination of mic and setting on the PD170. My conclusion is either the stock PD170 microphone is useless for outdoor videography or I have a problem. A problem with my knowledge of how to use the camera or a problem with the camera/mic. My azden made the PD170 work about at the level of the TRV950’s stock mic which is not too bad. I did get a level of ambient sounds on the PD170 that I think will work but it did not compare to the 950. With the azden on the 950, you can hear much much more and it is clear without distortion. What I get on the PD170 is clear but the sensitivity is not near that of the 950. I guess more “testing” is in order.

Any ideas?

With my wireless on ch2, AGC on, and the azden on ch1 w/AGC off, turned up 3/4, it worked pretty good. I just did not hear the "woods" like I wanted.

Thanks,

[David Ennis]

For the stock mics, I guess the PD170's "professional" status has given it a directional mic more intended for ENG interviews than for picking up the ambience at a family birthday or barbeque. The latter is what the stock mics on consumer cameras are desgned for. They're omni and very sensitive.

For external mics, the TRV950 has a very sensitive input. It's spec'd at a nominal 0.338mV, compared to the PD170's 0.8. That accounts for about 6dB of difference in performance. So far, this isn't the 170's fault, its spec is the more typical of the two. But those specs are based upon response to 1000Hz sounds. I've never seen the frequency response of a cam's mic input spec'd out, probably because they're not so great, now that I think about it. If so, frequency response may vary a lot among makes and models. Bottom line you might loose signifcantly more, as compared to the TRV950 in the higher frequency range of ambient sounds.

Also, the input impedance of the TRV950 is 6800 ohms while the PD170's is only 3000. The Azden's output impedance is 680 ohms. You lose another dB or so there, as a higher proportion of the voltage developed in the Azden is dropped across its own innards.

Maybe it's true that the PD170's sound capabilities suck, or maybe it would be great with a higher output, lower impedance mic.

I hear that one of the benefits of owning a PD170 is superior support from Sony's professional division. I suggest that you put that to the test.

[Steve Gray]

Thanks Fred. I have read where many have been happy with the sennheiser Me66/K6 on their PD170s and I saw that its impedance was 200 ohms. I did not know the specs on the 950 so thanks.

[Pete Wilie]

The Senn ME66 is a very hot mic and you will probably need to use an attenuator with it. You might also check out the AT897 which many people prefer over the ME66. Just do a search on "ME66 AND AT897" and you will get many posts discussing these mics.