TX308 - Speaker ALTO - Free user manual and instructions

Name: TX308
Brand: ALTO
Rating: 7 (187 reviews)

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Product Type	Active loudspeaker from the TX3 series
Brand	ALTO Professional
Model	TX308
Category	Loudspeaker
Power Supply	100–240 V AC, 50/60 Hz
Fuse	Correct rating (printed under the power entry), replaceable
Input Connection	Female XLR (line or microphone level)
Output Connection	Male XLR (for additional speaker)
Controls	Volume (with Line/Mic markings), power switch
LED Indicators	Power indicator (green) and clip indicator (green/red)
Protection Functions	Dynamic peak limiter to prevent distortion and damage
Compatible Source Types	Line (mixer, CD/MP3 player) and microphone/instrument
Mounting	On stand or pole (do not suspend)
Box Contents	TX308 speaker, power cable, user guide, safety instructions and warranty information
Maintenance	Keep ventilation openings clear
Safety	Do not use with the grille removed; follow mounting instructions and sound levels
Repairability	User-replaceable fuse
Support	Website: altoprofessional.com/support

Frequently Asked Questions - TX308 ALTO

How to adjust the volume for a line source?

Use the Line indicator band on the Volume knob. In most cases, do not exceed 0 dB. If the red LED stays on, reduce the source level or volume.

What does the red indicator on the rear panel mean?

The clip indicator (Signal Limit) lights up red when the internal protection circuit is activated by a high signal level. It dynamically reduces the signal to prevent distortion and protect the speakers. If the LED stays red, reduce the volume or source level.

Can I use a microphone with the TX308?

Yes, connect the microphone to the XLR input and adjust the volume using the Mic band. Since microphone level is lower, you can use the entire range of the Volume knob, but monitor the red indicator.

How to mount the speaker on a stand?

Place the speaker on a stand or pole suitable for its weight. Ensure the surface is flat and stable. Mount only one speaker per stand. Never suspend the speaker.

What to do if the sound is distorted?

Reduce the volume on the rear panel or the source level. If the red LED is continuously lit, the limiter is active. Lower the signal until the LED stays green.

Can I connect multiple TX308 speakers?

Yes, use the XLR output of the first speaker to the input of the next. This allows daisy-chaining multiple TX3 speakers.

How to replace the fuse?

Unplug the speaker, lift the fuse tab under the power entry, then replace with a fuse of the same rating (printed next to it). Never use a different rating.

What cables to use for the input?

Use a standard XLR cable (not included) to connect an audio source. The TX308 accepts both line and microphone level signals via the same XLR input.

Can the speaker be suspended?

No. TX3 series speakers are not designed for suspension. They should be mounted on a stand or placed on the floor.

Where to find technical support?

Visit altoprofessional.com/support for the latest information, technical support, and product registration.

User questions about TX308 ALTO

3 questions about this device. Answer the ones you know or ask your own.

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Which application or control should be used to adjust the equalizer of the ALTO TX308 speaker?

Frequently Asked Questions - 20 j

Response Notice-Facile

The ALTO TX308 speaker does not have a built-in equalizer or onboard tone controls. The only available controls are a volume knob and a power switch.

To adjust the frequency balance (bass, midrange, treble) with the TX308, you need to use the equalization controls of your audio source:

The equalizer of your mixer or preamplifier
The EQ controls of your audio interface
The music playback application on your device (smartphone, computer)
The settings of the audio processor or effect connected upstream

Note: Higher models in the ALTO series (TX312 and TX315) include a Contour switch that enhances bass and treble, but this feature is not available on the TX308. It is an entry-level model designed for simple and direct amplification.

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How can I improve the clarity of the vocals on my ALTO TX308 speaker?

Frequently Asked Questions - 20 j

Response Notice-Facile

If you are having trouble hearing the vocals with your ALTO TX308 speaker, the issue usually stems from a sound imbalance where the bass dominates. Here’s how to optimize audio clarity:

Check the input level

Make sure to use the correct volume band. The TX308 has a volume knob with two reference bands:

External band (Line): use it for mixer/CD/MP3 sources. The level should not exceed 0 dB.
Internal band (Mic): for microphones and instruments.

An overdriven source can create distortion that masks the highs (vocals). Ensure that your input signal is not too high.

Be mindful of the dynamic limiter

Your TX308 has a dynamics peak limiter that automatically activates during excessive sound peaks. Check the Signal Limit LED indicator:

Green: normal operation
Red: the limiter is active, which may affect the clarity of high sounds (vocals)

If the indicator is frequently red, reduce the input level at the source (mixer, audio player, etc.).

Placement and ventilation

Ensure that your speaker is placed stably (on a stand or on the floor) and that the ventilation ports remain clear. Poor ventilation can affect the amplifier's performance and overall audio reproduction.

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How to connect a jack plug to an ALTO TX308 speaker?

Frequently Asked Questions - 24/03/2026

Response Notice-Facile

The Alto TX308 speaker does not have a 6.35 mm jack input, but rather a balanced XLR input on its rear panel. Here’s how to connect your audio source to the TX308:

Preparation before connection: Before plugging in your source device, set the TX308 Volume knob to minimum (turn the knob completely counterclockwise). This step is essential to avoid sound spikes and potential damage to the speaker.

Connection via XLR input: Use a standard XLR cable (not provided) to connect your audio source to the XLR input of the TX308. The other end of the cable connects to your source device (mixer, CD/MP3 player, audio preamplifier, etc.). Firmly insert the XLR plug until it clicks into place.

Volume adjustment: The TX308 accepts both line level sources (mixer, CD/MP3 player, preamp) and microphone level sources (microphones, instruments). Follow the volume indicator strip: use the outer strip for line level sources (you generally should not exceed 0 dB), and the inner strip for microphones (you can use the entire range of the knob). Gradually increase the volume while observing the Signal Limit LED indicator on the back of the speaker.

Be cautious of strong signals: If the Signal Limit indicator lights up red continuously or if the sound is distorted, do not increase the volume further. This could damage the TX308. Instead, reduce the signal level at the source or slightly lower the Volume knob on the speaker.

Alternative for jack connection: If your audio source only has a 3.5 mm or 6.35 mm jack output, you will need to use a jack to XLR adapter cable (sold separately). This adapter will convert the signal from your source device to make it compatible with the XLR input of the TX308.

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Download the instructions for your Speaker in PDF format for free! Find your manual TX308 - ALTO and take your electronic device back in hand. On this page are published all the documents necessary for the use of your device. TX308 by ALTO.

USER MANUAL TX308 ALTO

TX308 TX312 TX310 TX315

User Guide

English (3-9)

Guía del usuario

Espanol (10-16)

Guide d'utilisation

Français (17-23)

Guida per l'uso

Italiano (24-30)

Benutzerhandbuch

Deutsch (31-37)

Appendix

English (39-42)

User Guide (English)

Introduction

Thank you for purchasing the TX3 Series loudspeaker. At Alto Professional, performance and reliability mean as much to us as they do to you. That's why we design our equipment with only one thing in mind—to make your performance the best it can be.

Box Contents

TX3 Series Loudspeaker

Power Cable

User Guide

Safety & Warranty Manual

Support

For the latest information about this product (system requirements, compatibility information, etc.) and product registration, visit altoprofessional.com.

For additional product support, visit altoprofessional.com/support.

Important Safety Precautions

Please note: Alto Professional and inMusic are not responsible for the use of its products or the misuse of this information for any purpose. Alto Professional and inMusic are not responsible for the misuse of its products caused by avoiding compliance with inspection and maintenance procedures. Please also refer to the included safety and warranty manual for more information.

ALTO TX308 - Important Safety Precautions - 1

Caution: To reduce the risk of electric shock, do not connect a TX3 Series loudspeaker to a power outlet while the grille is removed.

Stand-Mounting

Important: Do not suspend a TX3 Series loudspeaker. It is not designed for suspended applications.

Always install loudspeakers in accordance with applicable electrical and building codes.
- Install the loudspeaker according to its maximum weight. Check the specifications of your stand or pole to ensure it can support the loudspeaker's weight.
- Observe all safety precautions specified by the stand manufacturer.
- Do not mount multiple loudspeakers on the same stand or pole.
Always verify that the stand or pole is on a flat, level, and stable surface.
- Always be cautious in windy, outdoor conditions. Do not attach anything to the loudspeaker other than cables or equipment necessary for standard operation.
Unless you are confident that you can handle the loudspeaker's weight, ask another person to help you lift it onto the stand or pole.
Make sure your cables are out of the way of performers, production crew, and audience.

Sound Level

Permanent hearing loss may be caused by exposure to extremely high noise levels. The U.S. Occupational Safety and Health Administration (OSHA) has specified permissible exposures to certain noise levels. According to OSHA, exposure to high sound pressure levels (SPL) in excess of these limits may result in hearing loss. When using equipment capable of generating high SPL, use hearing protection while such equipment is under operation.

Hours per day	SPL (dB)	Example
8	90	Small
6	92	Train
4	95	Subway
3	97	High-level
2	100 Classical music concert
1.5	102	Riveting
1	105	Machine
0.5	110	Airport
0.25 or less	115 Rock concert

Setup

Volume Control (TX308 & TX310 only)

The TX308 and TX310 loudspeakers accept both line-level and mic-level audio sources. Before connecting your audio source, turn the Volume knob to the minimum position (fully counter-clockwise).

ALTO TX308 - Volume Control (TX308 & TX310 only) - 1

Line-Level Audio Source

When using an audio source such as a mixer, CD/MP3 player or audio preamp, follow the outer/Line level band indicator.

ALTO TX308 - Line-Level Audio Source - 1

If the Signal Limit LED is lit red constantly or the sound is distorted, do not advance the Volume knob any further. Doing so may damage your TX3 loudspeaker. Reduce the signal level of your sound source, or lower the volume with the Volume knob.

In most circumstances, you will not need to turn the volume beyond 0 dB.

If your audio source has unusually low output, you may turn the Volume knob past 0 dB, but not past the Signal Limit indicator (as explained above).

Mic-Level Audio Source

Important: If you are using an instrument with active preamp, treat the instrument as a line-level audio source (as explained above).

When using a microphone or instrument audio source, follow the inner/Mic level band indicator.

Because the mic and instrument level is typically lower than a line level, you can use the full rotation of the Volume knob.

As you turn up the Volume knob, please observe the Signal Limit indicator. If the Signal Limit LED is lit red constantly or the sound is distorted, do not advance the Volume knob any further. Doing so may damage your TX3 loudspeaker. Reduce the signal level of your sound source, or lower the volume with the Volume knob.

ALTO TX308 - Mic-Level Audio Source - 1

ALTO TX308 - Mic-Level Audio Source - 2

ALTO TX308 - Mic-Level Audio Source - 3

Examples

Items not listed under Introduction > Box Contents are sold separately.

Note: These examples show the rear panel used by the TX312 and TX315 models, though all four models in the TX3 Series have the same input and output.

Example A: Two Loudspeakers

Connect each of your mixer's main outputs to the input on a TX3 loudspeaker. If you are using a TX308 or TX310, do not turn the Volume knobs past the 0 dB position. If you are using a TX312 or TX315, make sure the input selectors are set to Line.

ALTO TX308 - Example A: Two Loudspeakers - 1
Mixer Power Outlet Power Outlet

Example B: Two loudspeakers + Two extensions

ALTO TX308 - Example B: Two loudspeakers + Two extensions - 1

Features

Rear Panel: TX308 & TX310

AC Input: Use the included power cable to connect this input to a power outlet. Make sure the Power Switch is set to off when connecting or disconnecting the cable.
Fuse: If the unit's fuse is broken, lift this tab to replace the fuse. Replace it with a fuse with an appropriate rating (printed under the unit's power cable input). Using a fuse with an incorrect rating can damage the unit and/or fuse.
Power Switch: Use this switch to power the loudspeaker on or off. Make sure the Volume knob is set to its minimum (counterclockwise) position before turning it on.
Power LED: This LED lights up when the loudspeaker is on.
Cooling Vent: Keep the area in front of this vent clear from obstructions.
Volume: Turn this knob to adjust the loudspeaker's volume.

When using an audio source such as a mixer, CD/MP3 player or audio preamp, follow the outer/Line level band indicator. In most circumstances, you will not need to turn the volume beyond 0 dB. If your audio source has unusually low output, you may turn the Volume knob past 0 dB, but not past the Signal Limit indicator.

When using a microphone or instrument audio source, follow the inner/Mic level band indicator. Because the mic and instrument level is typically lower than a line level, you can use the full rotation of the Volume knob.

ALTO TX308 - Rear Panel: TX308 & TX310 - 1

Please see Setup > Volume Control to learn more.

Input: Use a standard XLR cable (not included) to connect your audio source to this input. Make sure to set the Volume knob to the correct position.
Mix Out: Use a standard XLR cable (not included) to connect this output to the input of another loudspeaker (i.e., another TX3 loudspeaker).
Signal/Limit LED: This light illuminates green when audio signal is received and lights red when a high audio signal level activates the internal protection circuit. The protection circuit dynamically reduces the signal level to avoid audible distortion and to protect the woofer and high-frequency driver from over-excursion or mechanical damage. If this light is lit constantly, or the sound is distorted, reduce the signal level of your sound source, or lower the volume with the Volume knob.

Rear Panel: TX312 & TX315

AC Input: Use the included power cable to connect this input to a power outlet. Make sure the Power Switch is set to off when connecting or disconnecting the cable.
Fuse: If the unit's fuse is broken, lift this tab to replace the fuse. Replace it with a fuse with an appropriate rating (printed under the unit's power cable input). Using a fuse with an incorrect rating can damage the unit and/or fuse.
Power Switch: Use this switch to power the loudspeaker on or off. Make sure the Volume knob is set to its minimum (counterclockwise) position before turning it on.
Power LED: This LED lights up when the loudspeaker is on.
Cooling Vent: Keep the area in front of this vent clear from obstructions. The fan behind the vent cools the amplifier, preventing overheating.
Volume: Turn this knob to adjust the loudspeaker's volume.
Input: Use a standard XLR or 1/4'' (6.35 mm) TRS cable (not included) to connect your audio source to this input. Make sure to set the Input Selector to the correct position.
Input Selector: Set this switch to the Line position when using a line-level audio source connected to the Input. Set this switch to the Mic position when using a microphone connected to the Input.
Mix Out: Use a standard XLR cable (not included) to connect this output to the input of another loudspeaker (i.e., another TX3 loudspeaker).
Signal/Limit LED: This light illuminates when a high audio signal level activates the internal protection circuit. The protection circuit dynamically reduces the signal level to avoid audible distortion and to protect the woofer and high-frequency driver from over-excursion or mechanical damage. If this light is lit constantly, or the sound is distorted, reduce the signal level of your sound source, or lower the volume with the Volume knob.
Contour: Engage (depress) this button to emphasize low and high frequencies by +3 dB. Disengage (raise) the switch for a flatter response for live performance or for maximum output.
Ground Switch: Engage (depress) this switch to reduce hum or noise.

ALTO TX308 - Rear Panel: TX312 & TX315 - 1

Ingresso: servirsi di un cavo standard XLR (non in dotazione) per collegare una fonte audio a quello ingresso. Assicurarsi di posizionare correttamente la manopola Volume.
Uscita mix: serviri di un cavo standard XLR (non in dotazione) per collegare questa uscita all'ingresso di un'alto altoparlante (ad es. un'alto altoparlante TX3).
LED Signal Limit (segnale limite): Anything LED is, for example, a signale in the sense of "sounding" or "feeling". It is also called "sound", which means that it is a sound that can be heard by the listener. It is usually used to describe the feeling of being heard by someone else. It is also used to describe the feeling of being heard by people who are not hearing well enough to distinguish between the two senses.

Pannello posteriore: TX312 e TX315

Technical Specifications

Specifications are subject to change without notice.

TX308

System Type	2-way active ported loudspeaker
Drivers	Low-Frequency: 8.0" (203 mm) driver, 1.4" (35.5 mm) voice coil High-Frequency: 1.0" (25 mm) titanium-diaphragm compression driver, 1.0" (25 mm) voice coil
Amplifier	350 watts (peak), 175 watts (continuous), Class D power
Horn Coverage	90° horizontal x 60° vertical (nominal)
Frequency Response	75 Hz - 20 kHz (-3 dB)
Crossover Frequency	2.5 kHz
Max SPL	113 dB @ 1 m
Connectors	(1) XLR balanced input (Line/Mic) (1) XLR output (Link) (1) IEC power cable input
Controls	Power switch, volume control knob
Indicators	(2) power LEDs (1 front panel, 1 rear panel), clip limiter LED
Power	Connection: IEC Voltage: 100-240 V~; 50/60 Hz Fuse: T2AL/250V Consumption: 150 W
Protection	Thermal, overload analog limiter/compressor
Enclosure	Injection-molded polypropylene, multi-angle for main or monitor applications, metal grille, rubber feet, 1 handle on top
Mounting/Installation	Standard 36 mm pole socket, wedge monitor
Dimensions Height x width x depth)	16.6" x 10.7" x 9.9" 422 x 272 x 251 mm
Weight	12.3 lb 5.6 kg

TX310

System Type	2-way active ported loudspeaker
Drivers	Low-Frequency: 10.0" (254 mm) driver, 1.4" (35.5 mm) voice coil High-Frequency: 1.0" (25 mm) titanium-diaphragm compression driver, 1.0" (25 mm) voice coil
Amplifier	350 watts (peak), 175 watts (continuous), Class D power
Horn Coverage	90° horizontal x 60° vertical (nominal)
Frequency Response	75 Hz - 20 kHz (-3 dB)
Crossover Frequency	2.5 kHz
Max SPL	116 dB @ 1 m
Connectors	(1) XLR balanced input (Line/Mic) (1) XLR output (Link) (1) IEC power cable input
Controls	Power switch, volume control knob
Indicators	(2) power LEDs (1 front panel, 1 rear panel), clip limiter LED
Power	Connection: IEC Voltage: 100-240 V~; 50/60 Hz Fuse: T2AL/250V Consumption: 150 W
Protection	Thermal, overload analog limiter/compressor
Enclosure	Injection-molded polypropylene, multi-angle for main or monitor applications, metal grille, rubber feet, 1 handle on top
Mounting/Installation	Standard 36 mm pole socket, wedge monitor
Dimensions Height x width x depth)	18.2" x 11.2" x 11.0" 462 x 284 x 279 mm
Weight	13.4 lb 6.1 kg

TX312

System Type	2-way active ported loudspeaker
Drivers	Low-Frequency: 12.0" (305 mm) driver, 2.0" (51 mm) voice coil High-Frequency: 1.0" (25 mm) titanium-diaphragm compression driver, 1.0" (25 mm) voice coil
Amplifier	700 watts (peak), 350 (continuous), Class D power
Horn Coverage	90° horizontal x 60° vertical (nominal)
Frequency Response	70 Hz - 20 kHz (-3 dB)
Crossover Frequency	2.5 kHz
Max SPL	118 dB @ 1 m
Equalization	Contour switch with low- and high-frequency +3 dB boost
Connectors	(1) XLR/TRS 1/4" (6.35 mm) balanced input (Line/Mic) (1) XLR output (Link) (1) IEC power cable input
Controls	Power switch, volume control knob, contour switch, ground-lift switch
Indicators	(2) power LEDs (1 front panel, 1 rear panel), clip limiter LED
Power	Connection: IEC Voltage: 100-120 V~, or 220-240 V~; 50/60 Hz Fuse: 100-120V T6.3AL AC250V or 220-240V T3.15AL AC250V Consumption: 350 W
Protection	Thermal, overload analog limiter/compressor
Enclosure	Injection-molded polypropylene, multi-angle for main or monitor applications, metal grille, rubber feet, 2 handles (both sides)
Mounting/Installation	Standard 36 mm pole socket, wedge monitor
Dimensions Height x width x depth)	23.7" x 15.0" x 13.5" 602 x 381 x 343 mm
Weight	29.3 lb 13.3 kg

TX315

System Type	2-way active ported loudspeaker
Drivers	Low-Frequency: 15.0" (381 mm) driver, 2.0" (51 mm) voice coil High-Frequency: 1.0" (25 mm) titanium-diaphragm compression driver, 1.0" (25 mm) voice coil
Amplifier	700 watts (peak), 350 (continuous), Class D power
Horn Coverage	90° horizontal x 60° vertical (nominal)
Frequency Response	65 Hz - 20 kHz (-3 dB)
Crossover Frequency	2.2 kHz
Max SPL	119 dB @ 1 m
Equalization	Contour switch with low- and high-frequency +3 dB boost
Connectors	(1) XLR/TRS 1/4" (6.35 mm) balanced input (Line/Mic) (1) XLR output (Link) (1) IEC power cable input
Controls	Power switch, volume control knob, contour switch, ground-lift switch
Indicators	(2) power LEDs (1 front panel, 1 rear panel), clip limiter LED
Power	Connection: IEC Voltage: 100-120 V~, or 220-240 V~; 50/60 Hz Fuse: 100-120V T6.3AL AC250V or 220-240V T3.15AL AC250V Consumption: 350 W
Protection	Thermal, overload analog limiter/compressor
Enclosure	Injection-molded polypropylene, multi-angle for main or monitor applications, metal grille, rubber feet, 2 handles (both sides)
Mounting/Installation	Standard 36 mm pole socket, wedge monitor
Dimensions Height x width x depth)	24.9" x 15.2" x 14.6" 634 x 386 x 371 mm
Weight	31.7 lb 14.4 kg

Trademarks & Licenses

Alto Professional is a trademark of inMusic Brands, Inc., registered in the U.S. and other countries. All other product names, company names, trademarks, or trade names are those of their respective owners.