Visivox SCM-Pro

THE VISIVOX SCM-PRO MICROPHONE (sold as a stereo pair) appears to be attracting attention from people looking for a budget microphone to record birds, and it’s the first I used for this purpose. Among the features that make it worth considering is the relatively low noise of 20 dBA (A-weighted). The recorder I use it with is the Xclef HD800 personal music player, a "jukebox" with a 20 Mb hard disk. This has a line-in connection, and each stereo pair of microphones is connected via a single Visivox SCM-Pre preamplifier -- a required piece of gear that’s needed to amplify the tiny signals from the microphones. The mics and preamp are made by Jon Enoch in BC, Canada, and the approximate cost when I bought in 2004 was US$134 for a stereo pair plus preamp. I found Jon very helpful and he answered queries promptly.

(July 2006: See bottom of page for updated information, which may mean that some of my comments -- eg on RF interference from disk motors -- no longer apply)


The first clip is a set of extracts to show what the setup can do under good (silent) conditions. The quietest part is the Wren zitting at 24 sec to 34 sec. The original recording has been amplified by 9 dB, or 300%.

Visivox extracts (1.19 Mb) 160 kb/s mp3

The next clip was made on a windy day, but is quite dramatic. The birds were wheeling almost overhead. The last clip, of a female Tawny Owl, was made at dead of night from a window.

Hobbies (bird of prey) (341.63 K)

female owl (565.92 K)

Many would find these quite acceptable.

At the bottom of this page, Scrapbook page 5, you can compare the last clip with a recording of the same female tawny made with a really good mic, the Rode NT1-A. Both recordings were made from the same window with the owl probably in the same tree, though two years apart!

I no longer use the SCM-Pro as a primary recording mic as my ambitions outstripped its capabilities. I found the intrinsic noise floor a problem. This is (just) audible before any amplification of your recordings. If you can get close to birds you can get excellent results, but don’t expect to be able to amplify more distant birds much because the amplified self-noise becomes too intrusive. This is something you can do with quieter mics, and it’s a huge advantage. More expensive mics like those linked at left (the Sony mic excepted) are seriously quiet -- right down to 5 dBA for the Røde NT1-A. I should add here that at the price you're unlikely to find better than the 20 dBA of the SCM-Pros. It’s an unfortunate dilemma and quite simply put: I recorded for six months with these mics and ended up realising I would have to spend many times more than they cost on the Telinga mic and dish. The first night I went out with this setup I got a couple of hours of professional-quality nightingale -- excerpts here.

Another problem is the tendency of the long lead to pick up interference hum from the disk motor in the recorder unless it's kept well clear -- something that’s difficult if you want to walk around with such a setup. Adding to the problem is that if you loop or coil the 6-foot lead there is a noticeable increase in noise (hiss), even when motor noise is eliminated by keeping the lead away from the recorder. It's advisable to craft some kind of frame to hold the mics -- they come with clips, so this isn’t too difficult. If you think of trying the SCM-Pros for outdoors work I’d recommend asking Jon to provide them with a shorter lead.

On the other hand, a good point is that the mic and preamp perform well in damp and/or cold conditions. I leave them out in a polythene bag for rain protection all night with no problem. The bags I use are the resealable kind, so as an opening has to be left to run the leads out it probably gets as humid inside as out.

So basically my main use for the mic is for monitoring -- leaving the mic/recorder setup outside on a tree or bush for several hours to see who’s around. With a 4-5 hour battery runtime, that's seriously useful. It's a good way to record as many birds get curious about the new gadget in their territory and may come very close to investigate, as in the clip above.

The SCM-Pro mics plus pre-amp are good value and are a perfectly good choice for someone (like me!) who needs to find out how far they’re prepared to go in the bird or ambient sound recording hobby. If the sounds you want to record are reasonably loud you'll get very adequate results. If you're after more subtle sounds or quieter birds -- i.e. if your tracks need more than a touch of amplification -- you’ll find you have to spend rather more. And of course sheer sound quality, which I haven't gone into here, comes at a price.

July 2006

This is the Visivox site:

Visivox Technologies (opens in new window, click on the saxophone to enter).

There's also a Visivox eBay shop here. This is worth visiting as the mics are being offered with an upgraded version of the SCM pre-amp for just US$85 on eBay's "Buy It Now" scheme. The new pre-amp has a bass-cut filter (<100 kHz), which is often useful in outdoors recording. The maker claims improved self-noise performance from upgraded components in the pre-amp. Plug-in power (PIP) is now also provided. The mics are now called "SCM Broadcast Pro" and a stereo pair sells for US$35 (Buy It Now price), which has to be pretty good. (July 2007: the Visivox eBay shop is active but has no items on sale)

Jon has emailed (2006) to say that the Visivox Technologies site (first link above) is about to be revamped with new pics and info on the upgraded equipment, so try visiting from end July for more info than I can give. But my verdict here and now is that if the mics + pre-amp package is as good as or better than my earlier version, it's a very good deal at US$85. The personal attention you get from small vendors like this is a big plus, and on top of that Jon Enoch is a musician, which has to be a recommendation for a microphone maker.

3 September 2006 -- More Visivox samples

I've just found another good sample that's been lurking elsewhere on this website. It's of a couple of Tawny Owl fledglings being fed. The mics and Xclef recorder were hung out all night on a nearby tree trunk. Tawny fledgling feed (940.42 K) The background noise is amplified wind aided by late-night traffic rather than microphone noise -- 2004 was a very windy year, these babies were in an oak surounded by conifers, and this was the kind of noise I was getting from wind in trees all summer. The Visivox mics do well in this sample -- the calls of the chicks are accurately rendered and true to life. For a comparison with a tawny fledgling recorded with a more expensive mic (Rode NT1-A), go to Allan Haighton's page on this site and listen to "AH Tawny Owl 4" at the bottom of the page. Note, though, that this chick is making rather shorter, sharper calls than my two fledglings, so it isn't a like-for-like comparison.

There's a one-minute long Visivox sample on the pages of The Quiet American, recorded at night in Costa Rica. Unfortunately it isn't very helpful as the main sound appears to be crickets and/or tree frogs. Here's a link to the page (go to the entry for October 20, 2003; the clip is a 1.4 Mb mp3).

I haven't found any other samples made with this mic. There used to be one of a bird thought to be a Kokako, from New Zealand, but it seems to have been removed from the internet. Maybe someone said it wasn't a Kokako . . .


8 October

Dave Riley is using a Visivox setup to record telephone interviews and there's a sample on his blog page here. His conclusion: "This is an extraordinarily good microphone which . . . captures audio at a lecture superbly." Dave Riley is the creator of Ratbag Radio, a down-under podcasting outfit.

Page reviewed and updated 23 July 2007

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