Behringer Xenyx 1832FX Mixer

The Xenyx 1832FX is functionally similar to the older Eurorack UB1832FX Pro. The Xenyx version has different preamps and different EQ voicing. I can't comment on either or these changes, as I have no basis for comparison. The Xenyx version has a voice canceller function that can be applied to the CD/Tape inputs and a feedback indicator integrated into the graphic EQ.

Behringer is known for a wide range of low-cost audio products. The Xenyx 1832FX has six mic/line channels and four stereo line-level channels. Count the two stereo aux returns, and you have 18 input channels.

The 1832FX has three busses. One bus is pre-fader, permanently assigned to a monitor send. One bus may be pre- or post-fader per channel. The final bus is a post-fader send to a built-in effects processor. You can patch in an external processor if you desire.

Each channel, plus the internal (or external) effects return, can be routed to the main stereo bus and to the two subgroups. The effects return may also be routed to the monitor output.

The return for the bus that has selectable pre- or post-fader inputs is routed only to the main stereo bus.

Each of the two subgroups may be routed to the left and/or right channels of the main stereo bus.

A nine band graphic EQ may be assigned to the monitor output, the main stereo bus, or disabled. A feedback detection mechanism uses LEDs in the EQ's sliders to show which bands should be cut to eliminate feedback.

Each mono channel has a three-band semi-parametric EQ and a switchable low-cut filter. Interestingly, the mono channels do not have a pad switch. Mono channels have pan controls and unbalanced channel inserts. Phantom power may be turned on or off for all of the mic inputs together.

Each stereo channel has a switch to select +4 or -10 input levels, plus a four-band EQ. Interestingly, the stereo channels do not have a trim control. Stereo channels have balance controls.

Every input channel plus the monitor send and the internal effects return has a mute switch with a yellow LED to indicate that the mute is engaged. These same channels also have a solo switch and a red peak indicator LED. The peak LED serves double duty to indicate that the solo switch is engaged.

A twelve-segment stereo LED level meter is assignable to the sub busses, the main stereo bus and the CD/tape input. When a solo button is engaged the level meter displays only the solo'd channels. A PFL (pre-fader listen) mode solos the channel pre-fader, allowing for accurate setting of each channel's trim (or line source, in the case of the stereo channels).

In addition to the normal mixer features, a few extra gadgets anticipate specific uses. The internal FX processor may be bypassed using a footswitch. This would be handy for the band that runs their own sound, allowing the singer to make announcements without the effects normally applied to vocals. A very effective voice canceller would allow the 1832FX to be used as an impromptu karaoke machine. Finally, a stereo enhancement processor can be switched in to give recorded music a more dramatic soundstage.

A universal-voltage power supply is built in to the chassis of the 1832FX. No wall-wart for this inexpensive mixer!

The sonic performance of the 1832FX is adequate for my needs. Before the purchase I read a number of reviews complaining of extreme amounts of hiss. I suspect that those reviewers are unfamiliar with basic principles of mixer operation and gain staging.

Despite its extremely low cost, the 1832FX is a highly functional light-duty mixer. One has to assume that longevity and serviceability may have been compromised in order to achieve a sub-$300 price point for a unit having these capabilities. On the other hand, my previous experience with an even-less-expensive Behringer mixer leads me to believe that one can get years of flawless performance out of their mixers when used in a non-hostile environment.

When you buy a Behringer product, you best bet is to assume that you're on your own.

I immediately encountered a strange interaction between my Digitech RP355 and the stereo channels of the 1832FX. Once the RP355 had been plugged in to the channel for ten seconds or so, any sound on that channel was distorted. Additionally, operating the channel mute or fader produced very severe pops and scratches, respectively. Unplugging and replugging the connections to the channel cleared up all these symptoms momentarily, only to have them return some ten seconds later.

I did some basic troubleshooting, took careful notes, and emailed the support staff at both companies. I emphasized that I believed the problem to be related not to a failure of either unit, but rather to some unexpected interaction between the two. I asked for any information that might shed some light on the nature of the RP355's output circuit or the 1832FX's input circuit so that I could determine the cause of the interaction and devise a workaround. I emphasized that I was not looking for either vendor to offer a repair, as I firmly believed that both units were functioning properly and as-designed.

Digitech's response came mere hours later. Apparently their tech support people start work before I turn on my computer. The Digitech response was accompanied by an excerpt of the RP355 schematic illustrating the output circuitry, along with some insighful speculation about what might be happening at the mixer's input stage.

Based upon those hints from the *Digitech* support staff I was able to devise an experiment and take some measurements to illustrate that the stereo line inputs of the 1832FX need the DC resistance to ground to at least be in the same ballpark when using an unbalanced source. It turns out that the RP355 presents a DC resistance to ground of approximately 500K ohms. When the 1832FX sees a short to ground on the ring connection and a resistance higher than about 100K ohms at the tip, its input stage applies nearly 6 volts (!) to the tip connection. If the ring connection is left floating - or if the tip is presented with a DC resistance to ground of approximately 50K ohms or less - then the DC offset drops to about 1 mV.

So now I know what caused the problem and how I could fix it, all thanks to *Digitech's* support staff.

Nearly twenty hours after I sent both support requests I received a response from Behringer. Their answer: Since the problem only occurs with the RP355, that unit must be defective. OK, so they applied some basic deductive troubleshooting based upon my having forgotten to mention that the RP355 does in fact function normally under all other circumstances. My mistake. Assume nothing. But *then* the Behringer response went on to offer instructions on obtaining an RMA to get the 1832FX repaired. Um, hadn't they just implied that the mixer wasn't broken? (And it isn't...)

Lesson learned: Small companies have people who know what they're doing and are paid to think. Large companies have people who are paid to follow a script.

Behringer's tech support isn't the worst I've ever encountered (Tapco handily walks away with that dubious honor), but it's still as good as not having asked in the first place - entertainment value notwithstanding.

I use the 1832FX to mix multiple live sources in my music room. The output runs to a pair of QSC K10 powered speakers.

With the exception of the bizarre interaction between the 1832FX and my RP355 as described above, which could have been completely avoided had Behringer spent an extra 16 cents on eight more resistors rather than assuming that the presented source would become part of the bias network for their differential input stage, the 1832FX is an amazing value for the money and performs perfectly well for my application.