Zoom H4 battery

As readers look for the ideal mobile recording device, we’ve had ongoing, vibrant discussion about the Zoom H4. Its built-in stereo mic pair, real XLR jacks, and low price are big pluses — enough so that at least some are willing to overlook fidgety mic level settings. But one major problem could be a deal-breaker: an audible buzz in recordings.

Fortunately, it seems there’s a fix: if you don’t want to have to plug in the AC adapter all the time (which would defeat the purpose of a mobile recorder), make your own DIY battery pack. Zoom forums and RC car enthusiasts to the rescue!

Brad Linder, whom I met today at the NYC Jelly coworking session out in Brooklyn, is a blogger (Weblogs, Inc.) and NPR freelancer. Needless to say, NPR’s audio requirements will be higher than the typical amateur podcaster. Brad extensively documents his DIY RC battery pack.

Building an external battery pack for portable electronic devices [Brad Linder’s Digital Home]

Good stuff, and now that I’ve just gotten my own H4, I’ll be trying this out myself.

A couple of other questions come to mind, though: have others had trouble using external mics (which is part of the point of getting an H4)? And, power gurus, I wonder if a LiPoly battery (Polymer Lithium Ion), as used in cell phones and sold via vendors like SparkFun Electronics, could do the trick? They’re not cheap, but the slim design is a big improvement over the Ghostbuster-esque design above. Thoughts?

Zoom H4 Mobile Recording: Useful for Movie Production?

Zoom H2 Portable Flash Recorder Coming Soon; Mic Design Delay (with loads of comments from Zoom owners and folks who went with competitive devices like the Edirol mobile recorder)

  • Not having used one of these bad boys, I don't know if this question is completely ignorant or not, but why is the current battery causing a buzz? Might there be a way to fix the problem without an external solution? Shielding arount the battery or something?

  • Are you sure you haven't just got a faulty one ? when mine doesn't seem to buzz when using ordinary AA batteries, or am I going deaf ?

  • bliss

    For a second, looking at that photo, I thought this was an article about music and the war on terrorism.

  • Yeah, haha. I definately wouldn't want to try to get on an airplane with one of these.

  • Daryl: Essentially Zoom decided that the noise was acceptable for a low cost recorder and has no plans to issue an official update. Some members of the Zoom forums have figured out how to minimize the noise by tinkering around with the insides. But the only sure-fire way to eliminate the sound is to run off of AC power.

    Peter: The internal mic is great. Unfortunately this unit is not ideal for most external mics. Dynamic microphones just don't have a high enough output. And the preamps are pretty noisy with field condenser mics. I had some luck with a studio style condenser mic, but that's not ideal for most practical solution for most situations.

    The line inputs, on the other hand are clean as can be.

    For the price, the Zoom H-4 is a steal. But if you've got a bigger budget, you might want to check out higher end recorders from Fostex or Sound Devices for external mic support.

  • @Radian: Inconsistency from unit to unit? Absolutely possible! I've seen that happen with similar symptoms on other devices, so who knows?

    @Bliss/irez: Yeah, that was my first thought. I'll have to build a pretty custom shell if I do this. 🙂 I do seriously know someone who was stopped in security with a home-built battery pack. Behold, the world-crushing terrorist power of — BATTERIES!

    @Brad: That's funny, actually, because I think some of us were figuring on using studio condensers; for on-location music recording, that might be ideal (as would be line ins). For guerrilla reporting / field recording, etc., built-ins are the way to go, so it's terrific that you're solving this problem. It'll be interesting to see how the internal mics are on the smaller H-2 that's forthcoming from Zoom. (Still waiting on those to arrive; sounds like stocks will start to trickle in later this month.)

    But yeah, I agree, higher-end could be better if you can afford it … but then again, most of us aren't having trouble finding places to spend money.

    I may just have to give the LiPoly a try myself; I'd been looking for an excuse to play around with those anyway as they might be useful for a DIY wireless project.

    More tests soon … thanks for the tip, Brad!

  • I hear that those built in mics also pick up the sounds of your hands on the unit. Some one should make a handheld shockmount too hehe.

  • Zuofu

    Well, 2 AA batteries (the internal battery) only provide about 2.5 volts reliably (especially if you are using rechargeables), so chances are there is a switching boost converter on there to boost the voltage up to something higher and to provide both positive and negative voltage for op-amps etc. It's probably not a very good one, so I can see how some units might buzz. Same thing if you put your ear up to your cell phone screen when it's on…those LCD back lights require higher voltage than the 4 V or so those lithium poly batts can provide. You can try NIMH batteries if you are using Alkalines or vice versa, since the switching periods of those regulators depend on the input voltage, so it might be quieter if you use one kind of battery vs. another. Short of this solution or re-engineering the switching supplies on the H4 board….

  • yeah, the handling noise can be pretty bad. It's sort of like holding a mic without no shockmounting. But the Zoom does come with a tripod adapter, so if you're in a situation where you can set it up and leave it alone, that works. Otherwise, you learn to hold it very gently and not move your hand very much. This works for 15-30 minute interviews, but your wrist would fall off if you tried recording a whole concert this way.

    Overall, the reason I'm still using my Zoom is that the built-in mics and ability to record to WAV make the unit sound far cleaner than my old minidisc and EV RE-50 microphone, which is still standard fare for a lot of radio producers.

  • ok, this makes more sense to me now, thanks guys.

    @Bliss, yeah: "It had a very sinister appearance, it had a battery behind it, and wires." to quote the Boston Police.

    @irez, yeah a tripod is the way to go unless your one of those human-statue street performers.

  • mallyone

    So is it just a 60hz buzz when using the ac adapter and the solution is to have a 100% clean and consistant dc power source such as the batteries above or the suggested cell batteries?

    How effectively can the buzz be removed using post processing?

    I've always wanted to grab one of these for city environmental recordings, but in this rare case, I do not want a buzz :).


  • I only hear the dreaded beeping tone, when recording very low level sounds AND normalize the wav file afterwards.

    Unfortnately I often record low level field recordings…. Read on the zoom forum that it's caused by current draw on the internal battery by the disk 'Access' LED. Which make sense because the beeps coincide with the LED.

    However I just record to 96khz, where the 'Access' LED is lit up all the time. Therefore no change in power consumption and no beeping.

  • I don't have the problem with my H4, but then maybe it's because I record at 96khz too.

    Those mini-tripods they make for digital cameras are great for the H4 🙂

  • Ramesh


    Can someone pl tell me, how to hook up a 1/8" stereo mini (lapel microphone-sony) to the xlr input. Do i need both the xlr input1 and 2 or is it enough just XLR Input1 or input2?

    The xlr inputs are marked 1,2 and 3. Are they, the two signal line and a shield?

    Thanks -Ramesh

  • Ramesh

    My previous comment was for the zoom h4 recorder.

  • I need to buy a condenser mic for my new Zoom H4 today and am looking for a quickie recommendation. Can anyone help?

  • PS – I need the external mic for interviews for radio.

  • Chris

    you could try the Rode XY stereo mic "NT4" as an external option as it has a battery option as well therefore no need to supply phantom pwr from H4.

  • Art Simon

    Sounds like the H2 does not have the buzz. Here's a podcast where you can here the H4 versus the H2.
    They call the buzz a "whistle", and the H4 noise is pretty insignificant IMHO if there is any ambient noise whatsoever. Still, I'm happy I got the H2.

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  • Boovyfosho

    I, too, heard that notorious beeping Zoom H4 but, oddly enough, after having it almost a year, was only aware of recently when I started using it in very quiet rooms for interviews.

    Then I found this site, took Moljen's advice and set it to 96kh and the issue went away.

    I'm also going to attempt Brand Linder's DIY battery pack though I can't say I'm crazy about hacking the power supply that came with the Zoom.

  • Am I totally missing something here? I just bought an H4 and I think its the best thing for portable mic recording I've ever owned but I just can't gte it to record line inputs from a mixing board properly?!?!

    I've used balanced XLRs and unbalanced 1/4" cables from my mixer and all I get is tons of static/noise and just a bit of music coming through!?!?

    Has anyone managed to record a line input properly? I've even tried switching between battery and a/c power to no avail!?


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  • alihutch

    I have recently bought a Zoom H4 for recording interviews for radio. I've been pleasantly suprised by the internal mics but was wanting to use an external mono mic, partly so that I can see the screen when recording and so that my wrist doesn't break! I bought a ATM10a but found that the level just wasn't high enough. From looking around I'm beginning to realise that isn't' just me. Has anyone found a mic that doesn' generate enough O/P for speech recording or has anyone tried using some sort of small preamp? Thanks for your help!

  • hitman

    I've had the zoom H4 for about 4 months now and tonight have just started to notice a buzzing sound on recordings. It does'nt appear to be present on past recordings. I swapped my batteries (I use AA batteries) for new ones and the sound seemed to disappear but now its back. I tried the fix outlined above and recorded at 96KHz but noticed that the LED access light still flashed and the noise was reduced but still there. I tried again and this time the buzzing went, although background interferance was higher. Any thoughts or has my Zoom developed a fault?

  • hitman

    should have said that the sound I'm hearing is not the same as on the Brad Linder site but louder and more rythmic – very much like the interference you used to have with a tape looping!

  • Dwayne

    Hello Everyone, I also am the proud owner of the Zoom H4 and I've used it with line I/O, The Internal X/Y Mics and my 2 NADY SCM-800 Microphones and have been completely pleased with the results. I am using a 6 place AA Battery holder (9VDC) and still also use the ZOOm AC Adapter and have had good results. With the internal AA Batteries I get the quiet beeping but when I use external power its clean audio. I have made some fantastic digital recordings with pro level results.

  • Hi folks,

    A few useful tips. The current updated software has a high pass filter on a scale of 1 to 10 to cut handling and wind noise. Rycote make a 'Softie' for the H4 which makes outdoor recording a breeze, if you can pardon the pun. The part number is 0055355. Contact details are:

    Denise Leivers

    Rycote Microphone Windshields Limited

    Registered Office: Libby's Drive, Slad Road , Stroud, Gloucestershire. GL5 1RN U.K.

    Registered Number: 02972455

    Tel: + 44 (0) 1453 759338

    Fax: + 44 (0) 1453 764249

    Website: http://www.rycote.com
    Email: denise@rycote.com

    The cost was about £24.00.

    My last jazz album was recorded on the H4. Have a listen at http://martinrider.podbean.com The guitar was plugged straight into the line input. I e-mailed Zoom regarding the 'beep' (only on MP3 settings on mine) and received no response. Come on Zoom, you can do better than that!