ISO or EQ?


I’m a house/ techno DJ…which way do you all have the EQ’s set when transitioning? Why would I choose one over the other? I have it at EQ currently.


R&B, HipHop and Commerical DJ here. I have it set at ISO because I don’t want the different basslines of the tracks I’m mixing causing phase issues on the sound system.

I used to have analog mixers and they are mostly set as EQ.

I, however, prefer ISO on the X1800 and mostly mix in combination with the filter knob.

An iso is just a crossover that is summed. It has a fixed amount of group delay phase distortion and each band knob controls the attenuation/boost of the crossover bands. Interestingly, it was not only early house DJs that used Isos but also reggae dancehall traveling “sound systems” that did, and the latter often put the literal sound system crossovers (not electrically-summed) directly in the hands of the DJ.

A normal EQ, in contrast, alters the signal (using various electronics techniques) from its baseline with the EQ knob at 12 o’clock to some magnitude of change to that band away from center, increasing group delay phase distortion as you get away from center.

The X1800, as a digital mixer, will have what are called IIR digital models of these tone controls they included.

Isos allow full cut. Most EQs do not. EQs often have a point of greater change along the frequency response they cause for the band you’re controlling compared to Isos that will affect the entire band as evenly as possible for the filters used.

On a fixed-input-gain digital mixer like the X1800, you can hypothetically use nothing but the Isos if you want and never touch the gain/trim knobs, in contrast to the Pioneers (DJM800-2000) where you have to be careful with how the tone knobs affect the channel metering that are telling you analog input levels (newest Pioneers added “clip” word LEDs to help mitigate this).

Also on the X1800 we have a unique and welcome Iso-bypass that’s in-effect when all the tone knobs for a channel are centered. So you will get no difference in signal between the Iso and EQ modes on the X1800 if that channel’s tone knobs are at 12 o’clock.

If EQ mode on the X1800 is doing full cut (can’t remember if it does), it’s probably like -20 to -40dB down at the second to last leftward point on knob rotation and then just a cheated band mute at the furthest left point, but I’m at the computer and not at the mixer right now. So you might also get no difference in signal between the two modes when comparing a tone knob full left… not sure on that, though.

Which mode you choose, Iso or EQ, should have more to do with whether you do or don’t mostly like to often use just small amounts of tone change and with respect to if you particularly desire or dislike the sound the phase distortion of an Iso gives the music… granted in order to get the latter on the X1800 you not only need to have Iso selected but at least one tone knob on that channel tweaked out of 12 o’clock. You might find Isos sound a little off to you on some sound systems & headphones so that you prefer a more transparent sound to the original signal, or you might find a lack of Iso signature to possibly sound too dry, particularly for some types of electronic music. If you come from a background of using external Isos, you might especially miss both the control and sound an Iso gives with your favorite house music, for instance.

In practice on the X1800 itself with most DJs in most applications, though, I think whatever mode it’s in will not make much difference to them. If you measure the modes with the knobs slightly tweaked from center on the X1800, you’ll notice the difference in the way test waveforms look immediately on a scope screen.


Thanks for taking the time to write this

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X1800 EQ mode does not do canned kill when full left. Not a bad thing, just adding info.