There’s no arguing that an integrated audio system upgrade, such as Garmins GMA340 or PS Engineerings PM8000, pays big returns in overall audio quality and builds in room for future growth. They also save room on the panel by keeping intercom and audio switching controls in a single box. Further, integrated audio panel/intercom systems have switched and unswitched auxiliary inputs for remote traffic systems, cellphone inputs, autopilot automation and engine monitoring warnings.

Downside? You have to wire all that stuff and that can get expensive. Even so, we strongly suggest considering a new combination audio panel/intercom and the rewiring and clean-up that goes along with the installation. In our view, investing in good audio is money we’ll spent. And pay a little extra for sturdy and attractive audio jack housings and push-to-talk switches for pilot and copilot, along with entertainment input jacks installed in areas that are easy to access without cluttering up the cabin with wires.

If the aircraft doesnt have an intercom of any kind-kind of rare these days-there wont be passenger audio jacks and the shop will need to remove or at least access the interior to route the wiring, mount the audio jacks and reassemble the interior. If this is the case, consider a full audio system upgrade rather than a standalone intercom. The fewer times a shop removes and reinstalls interior components, the better. Some interiors just never seem correct after removal.

Installation costs could get into the thousands for just a standalone intercom and it doesnt make much sense to spend that sum just for an intercom when a new integrated audio panel wont cost much more.

But if you currently have a good audio panel, say the Bendix/King KMA24, and the associated wiring is in good shape, a standalone intercom might be the best choice. Or, if you have a dated intercom such as the David Clark Isocom or an old Sigtronics SPA400, a modern intercom upgrade would be worth considering. Keep in mind, however, that your shop might want to replace the wiring and this sometimes means starting from scratch. don’t try to talk them out of it; performance will suffer with old, ratty wiring.

Pioneers in aircraft audio, PS Engineering set the standard by which all intercoms are judged, in our view. The PM1000-series four-seat intercom offers excellent audio with features that pilots want, chief among them being dual independent volume and squelch control for pilot and copilot, which is standard on the PM1000II. The rear seats retain the same volume and squelch setting as the copilot. Prices are $299 to $499.

The PM1000II is available with dual entertainment input-it comes standard with a single input-which allows crew and passengers to listen to their own music.

There’s also a crew isolation feature, so the front seats and rear passenger seats can be isolated for privacy. A readback recorder option is also available.

The PM1000-series is a mono intercom, so if stereo quality is your desire, you’ll need to step up to the PM3000 series, which also supports up to six seats. Unfortunately, the PM3000 doesnt have dual volume and squelch control. But we think that if you fill that many seats all the time, an integrated intercom/audio panel is a better solution. A version of the PM1000 is made for high-noise environments and even one for larger airplanes that utilize dual audio panels, such as King Airs with older Collins Pro-Line radios.

Our many years of using and installing the PM1000 series has proven that its one of if not the best choice in standalone intercoms for quality, features, price and factory technical support. Its wiring should be readily compatible with the companys combination audio/ICS panels, if installed correctly.

Northern Airborne Technologies (NAT) in Canada has perfected audio control for helicopters, airborne law enforcement and numerous other applications. The AA-80 series intercom fits right into this product line. Dual volume and squelch control plus entertainment input circuits are standard. The controls on NATs general aviation products are as rugged as they are in NATs higher-end products and are offered in various configurations and mounting schemes.

There are versions of the AA80 series that excel in entertainment input tricks and music muting options (AA85) and even include a way to adjust the volume on the music input circuit. Prices are $355 to $895.

Weve found NAT audio quality to be excellent-none of that tinny, raspy sound you get from lesser audio products. We havent seen many NAT intercom failures, either, which bodes well, in our view.

Sigtronics has achieved success with the four-place SPA400 and six-place SPA600 intercom systems over the years. These are basic intercoms that seem to get yanked from panels during major upgrades and replaced by integrated audio panels. The used market is loaded with removed units that can be had for as little as $50. Theyre OK for basic two-place trainers, in our opinion, but weve always frowned upon Sigtronics claim that their systems don’t need shielded wiring during installation.

There are just too many imperfections and stray signals in many aircraft electrical systems that end up as noise in the intercom circuit.The SAS-440 and six-seat SAS-640 has a one-touch squelch setting button that sets the squelch threshold for a given environment. It has pilot isolation and is available in multiple mounting schemes, which is helpful for tight panels.

There’s a stereo add-on module (RMS440 and RMS640) that allows for stereo entertainment input by receiving an input from a remote music device. The model SPA-4S is made for tight spaces, measuring 1 by 2.5 inches and can be mounted horizontally or vertically. Its a basic system, but has stereo capability and music input, plus it comes in a version made for high-noise environments, such as helicopters and warbirds.

The SCI-series intercoms offer dual volume and squelch control. The four- or six-place SCI-series systems don’t have music input capability, but can be an easy drop-in upgrade to an existing SPA400 or SPA600. A reader mentioned to us that the Sigtronics line is confusing, given the choices of different models and we don’t disagree. Sigtronics does, however, enjoy a lasting presence in the aircraft audio industry and keeps its intercom line from growing stale. Prices on Sigtronics products range from $219 to $479.

Flightcom makes products for the military and is well-known for their Denali line of noise-canceling headsets. The company founder started building intercoms after struggling to hear his flight instructor while taking lessons during the late 1980s. His portable design actually won our product of the year in 1986.

The model 403MC is pitched at space-limited panels, so if you just cant find room in your panel for an intercom, the 403MC might be your only hope. It measures 2.6 by 2.3 by 1 inch high. Its relatively no frills, but does have pilot isolation, entertainment input and failsafe circuitry. Price is $179.

The six-place 403D features a digital voice recorder, copying 32 seconds of communication, plus it has entertainment input with music muting during communications. This unit sells for $339.

When we looked at standalone intercoms some five years ago, we couldnt put our finger on a slam-dunk winner, given the choices in a narrow market niche.

Intercoms are tough to judge other than critiquing sound quality and basic features. Nothing has changed to sway our view. In general, a four-place intercom installation will cost close to $2000 installed, not counting entertainment switching and ANR headset interfaces and assuming no wiring exists. It may be less if sound wiring is already in place.

Were still impressed with PS Engineerings audio quality, standard features and reliability in their PM1000 series. Similarly, we think NAT has perfected the audio quality for small cockpits through trickle-down technology from their higher-end products. When an intercom system fails, it can cause all kinds of strange audio-related problems that just arent acceptable for any mission, so quality should be a priority.

Given this, our top recommendation goes to the PS Engineering PM1000II with a near second choice to NATs AA-80 intercoms as an alternative to an integrated audio panel/intercom unit. We think either would be a good choice. Just be sure your installer doesnt scrimp on necessary wiring upgrades. Theyre a must to get the most out of these systems.