Frequently Asked Questions

What speakers are in the TS4 lineup?

The TS4 series features 8-, 10-, 12-, and 15-inch woofer models. They are aptly named TS408, TS410, TS412, and TS415.

How many watts do the TS4 speakers output?

The 8- and 10-inch models are 2000 watts and the 12- and 15-inch are 2500 watts. 

What are the inputs on the TS4 speakers?

Each TS4 speaker has two Combo XLR and TRS jacks that support both balanced and unbalanced audio. They also receive Bluetooth signal when you pair a supported Bluetooth Device.

How do I pair my TS4 speaker with a Bluetooth device?

To connect the speaker with a Bluetooth device follow these steps: 

  • Hold down the pairing button for 3 seconds to initiate pairing.
  • The blue LED on the speaker will flash indicating that it is in pairing mode.
  • Navigate to your device's Bluetooth device list and select ”Alto TS408,” “Alto TS410,” “Alto TS412,” or “Alto TS415” to connect.
  • Once paired there will be a voice prompt stating the connection was successful, and the blue LED will be lit solid. 

Note: Pressing the pair button while in pairing mode will cancel the connection.

The TS4 speakers have a stereo link mode that will allow two TS4 speakers to be paired wirelessly. To set up the stereo link mode do the following steps: 


  • Connect one speaker to Bluetooth following the steps above. This will be the primary speaker.
  • Hold the pairing button for 3 seconds to initiate stereo link. Do this for both speakers.
  • Both speakers will beep to indicate they are in scanning mode, and the orange LED will blink. When they find each other, they will link automatically.
  • Once the two speakers are successfully linked, there will be a confirmation chime, and the Orange LED will be lit solid.
  • Press and hold the pair button on either speaker to disconnect. 

Once the speakers are in the stereo link, the Bluetooth Volume knob on either speaker will control volume for both speakers


  • If you link the speakers first, only one speaker will connect to Bluetooth.
  •  If pair mode is activated on both speakers (pair button held for 3 seconds), you may encounter trouble linking until pair mode is cancelled or times out. 
  • The stereo link is only for Bluetooth signal only. 

Mix Out does not include Bluetooth signal, only analog inputs. 

Why are there Mic/Line switches, and what do they do?

The Mic/Line switches let you select your input so that you can turn up the volume without fear of overdriving your TS4. If you are unsure of whether your input is Mic or Line, start with Line first and make sure your source volume is up sufficiently high. If this is still not loud enough, turn your volume all the way down, switch to mic, and turn up until an appropriate volume is reached.

Note: The TS4 series are optimized to provide maximum output for your source when the volume knobs are turned all the way up (5 o’clock).

What do I do if there is a delay between my linked speakers?

If you experience a delay between two linked speakers, please first try pausing and restarting your audio. If that does not work, try powering off both speakers and then re-linking them. 

What does the Sub Size button port do?

The Sub Size button optimizes the low frequencies of your TS4 when it is paired with a subwoofer. If you don’t have a sub, the “Full Range, No Sub” setting gives you the full, low-end output of your TS4, and is active when the LED is off. Technical values below:

  • Large - Roll-off at 80Hz.
  • Medium - Roll-off 95Hz.
  • Small - Roll-off 110Hz.

What is the power output of the USB charge output on the TS4 speakers?

The USB Charge output size is 5v, 2.1A. This output is used for charging devices, and cannot be used to stream media from storage or media devices. 

What does the "Speaker Use" button do?

The speaker use button will adjust your speaker to control the output EQ based on what is streaming through your speaker

  • EQ off setting is a flat setting for general use.
  • The Live setting has a bump in vocal frequencies, and a cut in the low end frequencies.
  • The DJ setting boosts the high and low ends for added clarity and thump.
  • The Custom via app setting allows you to control the EQ using the  free Alto Pro app

How do I adjust the EQ settings on the TS4 speakers?

The Speaker Use Presets provide one option for EQ adjustment. For greater control, the Alto Pro app offers a 6-band, parametric EQ for use with the “Custom via App” setting. You can manipulate the available sliders to get the sound you want, and then load it to your TS4 by pressing the “Load to Speaker” button. After setting the EQ you want, you can save your favorite settings for later use.

Is there a cover for the TS4 models? Will the TS3 covers fit? 

Yes, there  are covers exclusively for the TS4 models. Check the Alto Professional website to see the list of dealers from which you can  purchase one. Since the speakers have angled sides and different geometries from the prior models, the TS3 covers will not fit. The TS4 covers will also not fit the TS3 models. 

How do I turn the voice prompts off?

Press and hold the BT pair and TWS link buttons until you hear “voice off.” To turn it on again, do the same thing until you hear “voice on.”

Note: The voice prompt level is controlled by the BT volume knob.

Where can I download the TrueSonic 4 App? 

The Alto Professional TrueSonic 4 App is available to download for free on the Android and Apple app store.