Zoom H1 and noise in headphones

[Peter Berger]

Does anybody have Zoom H1 audio recorder?
I bought it and I have this problem... If I want to monitor the sound via headphones I need to really pump up the volume of line out (otherwise the sound is very quiet) . This increases the noise (only in headphones). The recorded sound is clean, but the monitoring is practically useless (when I hear noise in headphones all the time, I cant be sure if its only in headphones or if I am actually recording the noise). Its possible to fix this problem? Buy better headphones?
BTW, I am using Rode NTG2 mic (with Shure A96F transformer which adapts XLR-type connector to the 3.5 mm input).

[Jay Massengill]

Exactly what model of headphones are you using?

[Peter Berger]

Really cheap headphones (Pro-Luxe KT-323), but I dont have any problem with it when I connect it to the camera or to the computer.

[Rick Reineke]

A lot of powerful HP amp is sometimes needed, depending on the impedance and sensitivity of the HP.
The H1, like a lot of the budget portables do not have a lot of balls.
FWIW, Many location sound recordists use the Sony 7506 which don't need lot of power to drive.

[Peter Berger]

The headphones are more expensive then my Zoom H1 :)) But thanks for the link, I will consider it.

BTW, the mic preamp is also pretty weak. When I am recording with Rode NTG2, I need to increase the input volume (of Zoom H1) to 100% and then add more volume in post! I thought H1 is something like the popular H4n, only smaller, in cheaper (plastic) body and without XLR inputs.

[Peter Berger]

I have one more question - could be the low volume of the Rode NTG2 caused by Shure A96F transformer?

[Greg Miller]

Originally Posted by Peter Berger

could be the low volume of the Rode NTG2 caused by Shure A96F transformer?

Actually, that transformer should be increasing the mic's output voltage (the transformer output voltage is about +6 dB hotter than the mic's output voltage). Unfortunately, that mic, when battery powered, has an output impedance rated at 350 ohms... rather an unusual figure. Because of that, I think you should not consider changing the primary tap on the transformer (to 150 ohms, from the stock 600 ohms); doing so would give you several dB more level, but might load down the mic excessively.

As to whether the {mic + transformer} combination is "loud enough" for your recorder (and whatever situation you're shooting), the answer is: check the recording level meters. If you can't hit around -10 regularly, then you don't have enough system gain.

Unfortunately, many of the low-price handheld recorders seem to have barely enough mic gain. I suspect that's partly to save money, and partly to prevent the noise from the digital circuitry from bleeding into the audio.

[Peter Berger]

I can barely hit -24. I also tried external mic preamp with XLR input and the results were similar. On the other hand, when I plug this mic into my old Canon HV20 camera, everything is ok. I really dont understand why cheap camera has better mic preamp then external sound recorder and external mic preamp. I hate using my old HV20 camera for recording sound, but it seem its still the best solution for me (I am shooting with Canon 5D, so I need to record the sound externally).

Anyway, I am considering to buy a lav mic (probably Sennheiser ME2), because I mostly shoot static interviews). Do you think the results would be same with Zoom H1?

[Greg Miller]

First of all, are you sure you're providing proper battery power for the mic, since it's not running on phantom power?

I'm curious to know what external preamp you're using.

Also, with the external preamp, what kind of levels are you seeing on the preamp's meter?

[Peter Berger]

I am using fully charged 2800mAh batteries. As I said, when I plug it into my HV20 camera, the sound is fine.

I dont have the preamp anymore, I send it back, it was useless to me. It was Lexicon Alpha. With 100% mic input volume the recorded sound was at -24db.

I could also get rid off of my Zoom H1 and buy something better. Maybe Zoom H4N? Do you think it could solve my problem?

[Peter Berger]

BTW, here is a video showing Rode lav with Zoom H1 and the sound is fine.

RODE Lavalier Microphone on Vimeo

[Greg Miller]

Did you actually use a Rode lav, or any other unbalanced mic, plugged directly into your H1? I think we should confirm that the mic input on your H1 is working correctly.

Also, for the sake of reference, can you get good levels on your H1 with the internal mics?

When you used the NTG2 with the Canon HV20 camcorder, were you using the same Shure transformer? If the answer is "yes" then it would seem the transformer is wired correctly and is working OK with that mic.

The published specs for the H1 say input level is "0 to -39 dBm." If they mean that is the range of levels which will produce full-scale recorded level, that seems rather high compared to normal mic level.

The published specs for the H4 say input level is "-20 / -30 / -40 dBm." From these sets of numbers, it would appear the H4 mic input is not significantly more sensitive than the H1.

(And I don't find any published specs for the HV20 input sensitivity.)

So I don't see anything obvious yet. Perhaps your answers to the above questions will shed more light on the issue. Or perhaps someone who has used this or a similar combo can offer some suggestions.

[Peter Berger]

No, I didnt use Rode lav or other unbalanced mic with my H1 (i used only Rode NTG2).

Yes, I can get very good levels with the H1 internal mic (its a really big difference against mic input levels).

Yes, I did use the same Shure transformer with my HV20 camera.

(In user guide to Canon HV20 camera (http://www.camcorderanswers.com/manuals/canon-hv20.pdf) is this information: Mic terminal: -57dbv (with 800 ohm microphone)/5 kohms or more)

[Greg Miller]

Thanks, that gives us a little more data to consider.

First of all, if the H1 internal mics produce a good level, I think we can conclude that the internal preamp is working correctly.

From this we can probably assume that the mic input jack is working as designed, although of course there might be some sort of bad connectivity. You should verify that - easily - by trying some unbalanced lav directly into that jack.

Next, we might make another assumption: that the quoted gain figures (H1, H4, HV20) all refer to the input level that's needed for 0dB FS recording level. If that's true, then the Zooms have roughly 20dB less gain than the Canon.

(By the way, the input spec I quoted before, -39dBm, was for the older H4. The spec for the H4n is -42 dBm. This is a minor difference, compared to the spec for the Canon.)

Just to be 100% clear, I'd like to verify one other thing. I believe you stated that you got recording levels of -24dB when you recorded through an external preamp. What kind of levels do you get if you plug the {mic + transformer} directly into the H1, without the external preamp?

[Peter Berger]

When I am speaking 15cm (6 inches) from the mic I can get -12db (with 100% mic input volume).

With internal mic I am hitting 0db.

I found another video with Zoom H1 and RØDE Lavalier vs. Audio-Technica ATR3350 (showing the levels with this lav mics):

RØDE Lavalier vs. Audio-Technica ATR3350 with Zoom H1 - YouTube