In a see saw equalizer, a single control knob boosts and cuts at the same time up to +/- 16dB centered at a pivot frequency. The EQ50's third band is a high cut filter that is also continuously adjustable from 5kHz to over 200kHz and also rolls off or cuts 6dB per octave.

200kHz? The upper harmonics of transient laden audio sources--the fast attack of drums, pianos, and percussion instruments range from just inside the range of human hearing to well above our ability to hear. Due to degrading distortion and phase shift in the audio signal, the transient portion of the audio waveform is easily corrupted resulting in a timbre shift and unclear or muddy sound. This distortion can start with the original recording's microphone, the particular pre-amp and/or increases with subsequent processing during mixing.

Despite that the EQ50's high cut filter can be set outside the range of human hearing, using it at frequencies such as 20kHz to 50kHz will significantly reduce high frequency ringing and overshoot of the front, initial attack portion of transient sounds--drums, pianos and percussion instruments. And setting it for frequencies approaching 200kHz ensures that only non-audio signals are rejected, without degrading the audio frequency or phase response.

In The Studio

I first aligned the pair of EQ50 modules with a 1kHz test tone to insure that the see saw sections on each were exactly 'zeroed' and both modules produced the same output. I'd like to see a calibrated detent pot for the pivot frequency control to avoid having to do this with every use. I ran the mix of a song featuring an acoustic guitar and vocal through the EQ50s and with them both calibrated and set flat, there was no hearable difference or level shift switching them in and out of the stereo bus output--and that is a good thing!

Next I used the see saw mid-range section set to 1kHz to add a touch of "cut" and, at the same time, lower the frequencies below 1kHz. This is a touchy control used on program material this way--a little goes a long way! Later on, I cleaned up a single electric guitar track that was a little dull and thick sounding. A perfect application--I rolled out from 55Hz down and 'see sawed' about 1dB at 1kHz and the guitar sounded great and sat in the track in a natural way. I used the high cut filter section set at 10kHz but it didn't really affect the basic tonality or brightness--just more of the clean up process.

So I think the EQ50 is proving to be a transparent and super cleaning tool! I've only just started to deploy it in my mixes and it is not always the right equalizer for every source, but I must say it is smooth and subtle-sounding for most sources.

The EQ50 is meticulously designed to maintain an accurate phase/amplitude response for a fully transparent signal path when in circuit. Each Ingram Engineering EQ50 sells for $455 MSRP and for much more about it, check: www.ingramengineering.net/products_eq50.php.