Troubleshooting MC and MCA-66

Written by
HTD Staff
Published on
December 14, 2021 6:09:03 PM PST December 14, 2021 6:09:03 PM PSTth, December 14, 2021 6:09:03 PM PST

Here are the most common issues we hear about from customers using one of our whole-house audio systems built around the MC-66 or MCA-66, along with suggestions to resolve them.

Related to the MC App

App displays "System not found" or doesn't always connect to the system.

  • Most often this is due to a network issue, specifically that your smart phone or tablet is not connected to the same WiFi network as your system's gateway (model GW-SL1 or WGW-SL1). See "What are the biggest MISTAKES people make when preparing their home for a whole-house audio system?"
  • If you are using an iOS device, you must give permission for our app "to communicate with other devices on the network". If the app is not given permission to discover and communicate with the gateway, it will continue to state "System not found". Your device likely asked about this during initial installation of the app. To confirm this is set correctly on your iOS device, go to Settings > Privacy > Local Network. Find the MC app and make sure the toggle switch is set to "on". Note: as of this writing, Android devices do not require this setting.
  • Check the connection between the gateway and the MC-66 or MCA-66 central controller: Make sure the cable connected at the "RS232 SERIAL INTERFACE" is not loose but also not too tight causing the cable to back out of the connection.
  • Make sure the gateway is powered on and is connected to your network.
  • Model WGW-SL1 shipped after October, 2020 (it has a red stripe on the cover) can be connected wirelessly or with an ethernet cable, but NOT BOTH SIMULTANEOUSLY. If you previously set up this gateway for a wireless connection, but now prefer to use a wired connection, you must first reset the gateway to its factory defaults by depressing the button located near the antenna (while powered on) for 10 seconds.


I can't access the custom settings because that section is locked.

All MC-66 and MCA-66 ship with this section locked. If it were not locked, anyone with access to your home's WiFi would be able to download the app and make changes to these custom settings. We sent an email to you at the time your order was approved. This email included helpful information for setting up your system and also included your initial unlock code.

If you previously changed the initial unlock code to something more personal but now cannot remember the code, you will need to delete the MC app and set it up again using the initial unlock code. Your custom zone names, source names, groups and presets can be recovered using the RESTORE feature in System Settings, but ONLY if you previously used the BACKUP feature which saves this information in our free cloud.

Please contact us if you are unable to locate the initial unlock code and we can help.


The app occassionally "locks up".

This is almost always a case of too many volume commands being sent to the central controller all at once. When you use a volume slider in the app, volume does not begin to change until you release your finger from the screen. Once this happens, the difference between the current and new volume is calculated and the system gradually ramps volume up or down to meet the new volume number.

If you and/or someone else using the system at the same time attempt to make wide changes in volume levels in multiple zones simultaneously, the system can lock up. Power cycling the central controller, and force closing and reopening the app, should clear up the issue.

Best steps to power cycle your system:

  1. 1. Make sure amplifiers are in sleep mode or powered off
  2. 2. Power off the MC-66 or MCA-66 using the power button on the front.
  3. 3. Wait 10 seconds. Press the power button back in.
  4. 4. Power back on the amplifier(s) if powered off.

A KC6 or KC7 keypad is not working, or not working properly.

Keypads are only recognized by the system when the central controller (model MC-66 or MCA-66) is first powered on. If you connect a device while the system is already powered on, that device will not be recognized and will not work. Power cycle your system (steps above) to give the MC-66 or MCA-66 the opportunity to identify the keypad.

If the keypad was previously working properly, but it suddenly is not, power-cycling the system using the steps above will likely resolve the issue. That said, it is best to check the following that could have caused the issue in the first place:

  • Are you using a patch panel for your Cat 5 (or higher) cable? It is always best to avoid patch panels with a whole-house audio system. See "What are some of the biggest MISTAKES people make when preparing their home for a whole-house audio system?"
  • Check that both ends of your Cat cable followed the same 568A or 568B standard and that ALL 8 conductors are properly terminated. It is NOT okay to simply use your own sequence at both ends because the 8 conductors are more accurately defined as 4 twisted pairs. The "twisting" makes a difference - you must follow 568A or 568B. And, unlike ethernet which only makes use of 4 of the 8 conductors, HTD whole-house audio systems utilize all 8. See page 17 (Addendum) of the Owner's Manual for details.


Volume is not as loud or behaving as I expected.

Volume control on the MC-66 or MCA-66 ranges from mute (0) to a maximum of 60. With the app and the KC7 keypad, these numbers are clearly displayed; with the KC6, a series of 7 LEDs indicate the approximate position of volume across this same range of 60. With 60 unique volume levels, this gives you a fine level of detail for controlling volume.

For most listeners, everyday listening will typically have volume set in the 15-30 range. Loud parties, or outdoor spaces, may require a higher volume setting, but you should almost never need the system to get above 50.

If you are having to set zones to these higher volume numbers just to obtain everyday listening levels, then chances are good your system is not optimally set up. It is important to understand that the audio source will output a volume signal level, but only the amplifier creates volume. All other "volume controls" are simply attenuating (reducing) this level.

To troubleshoot, start with the source:

  • Traditional audio sources such as a DVD player provide a strong, fixed level audio output signal that is not likely to require any adjustment.
  • If you are connecting a smart phone or tablet as your source, you are likely using what is really a "headphone" output. This signal level is slightly lower than a traditional source output when its volume level is at maximum. That said, a smart phone can be a great source, but don't reduce the signal further by reducing the signal strength on the phone or tablet itself - keep it at maximum and control the volume level from the MC app or a keypad.
  • Some music streamers include a fixed audio output level and others allow it to be variable. When you set up your streamer for the first time (using their app), fixed volume is preferred. If unavailable, set the output volume level to maximum.

Next, consider the app used for the streaming service such as Spotify, Apple Music, Pandora, etc. Streaming service apps are primarily used to select the artist, song, or playlist you'd like to hear. If the app offers a fixed volume setting, use it. If not, set and keep the volume level at maximum.

Finally, check the level knobs on the front of your 12-channel amplifier(s). In most cases, these should also be turned all the way clockwise in order to get the most out of your amplifier's power. Adjust these level knobs counter-clockwise only when you want to limit or cap the volume for a particular zone (e.g. kids rooms or outdoor areas).

If most of your sources are performing as expected, but by comparison one has low volume, then you may simply be using a source with a low level output. We offer line gain-boosters that fix this. Read more.

If you are only experiencing a low volume issue in one zone and the level knobs on the front of the 12-channel amplifier for the speakers in that zone are turned all the way up, you may have a problem with your speaker wiring. When speakers are wired "out of phase" with one another, their sound waves can cancel each other out. This effect is most obvious with lower frequencies where sound waves are larger. The result is audio that sounds thin or weak.

A convenient way to check for this is to disconnect just one speaker at the amplifier. If you have two speakers in a zone and the sound improves when one or the other is disconnected, then they are wired out of phase. An easy fix is to swap the red and black wires on JUST ONE OF THE SPEAKERS. This will correct for any mis-wiring that may have occurred at either the amplifier or at one of the speaker terminals.


Not seeing your issue or are unable to resolve your issue? Please contact us and we will do our best to help.