Wiring Tsunami Super WAV Trigger (Qwiic) to Car Amplifier/Speakers

Thread Starter

doormachine

Joined Jun 15, 2022
6
  • Will the speakers and amplifier handle the audio file specifications, such as the frequency?
  • With the PSU I will roughly have 6A left after other devices, will this be enough if the volume is turned up to max or would it destroy the components?
  • Can the volume be adjusted with the gain control or level knob as I am not connecting it to a head unit?
  • Should I use Low Input or High?
  • Did I wire the devices correctly? I am not sure how to wire the amplifier & speakers to the Tsunami Super Wav Trigger, I left that wiring out, could someone advise?
  • Should I wire the amplifier ground to the ground near the N and L terminals on the PSU to avoid noise? I will have a stepper motor, sensors and other devices on this same ground line so I think I shouldn't.

Audio Board: Tsunami Super WAV Trigger (Qwiic)
Microcontroller: Adafruit Grand Central M4 Express

Audio File Specifications:
Mix: Stereo
Rate: 44100Hz
Format: 32-Bit float

Speaker, suggestions welcome:
Speaker x 2 (FR 10 HM - 4Ω):
Rated Power: 20W
Maximum Power: 30W
Nominal Impedance: 4Ω
Frequency Response: 95 – 22000Hz
or
Speaker x 2 (FR 8 - 4Ω):
Rated Power: 10W
Maximum Power: 15W
Nominal Impedance: 4Ω
Frequency Response: 130 – 20000Hz

Amplifier, suggestions welcome:
Amplifier (GM-A3702):
Power Source: 14.4VDC (10.8V to 15.1V allowable)
Current Consumption: 14.5A at continuous power @ 4Ω
Average Current Consumption: 4A (4Ω for two channels)
Maximum Power Output: 170W x 2 @ 4Ω
Continuous Power Output: 60W x 2 @ 14.4V, 4Ω 20Hz to 20kHz
Load Impedance: 4Ω (2Ω to 8Ω allowable)
Frequency Response: 10Hz to 70Hz (+0dB, -3dB)
Low Pass Filter - Cut Off Frequency: 80Hz
or
Amplifier (CE102):
Power Source: 12V Channel
Configuration: 2 Channel
Total Power Output: 100W
RMS Power @ 4Ω: 38W x 2
Peak Power @ 4Ω: 50W x 2
Speaker Impedance: 4Ω to 8Ω
Frequency Response: 20Hz to 20kHz

Power Supply (QP-320D):
DC Voltage: 12V
Rated Current: 10A
Current Range: 0 ~ 10A
Peak Current: 10A

CE102.png

GM-A3702.png
 

MisterBill2

Joined Jan 23, 2018
12,402
With "only 6 amps" of headroom based on the listed current draw, the system should be able to damage your hearing very well, even below maximum output.
But the question about overloading the power supply damaging the equipment, the answer is NO. Most power supplies will either drop the voltage or shut down completely when overloaded. If the voltage drops you may experience some distortion increase. That would be the probable result. Not a permanent increase, but just for the duration of the overload.
 

Audioguru again

Joined Oct 21, 2019
4,794
The small speakers produce NO BASS even the 3.3" one they say "with good bass reproduction". Its datasheet shows no bass for 2.5 octaves of low music frequencies. Most car speakers are much larger at 6.5" in the front doors, 6" x 9" speakers on the rear shelf and a 10" or 12" subwoofer in the trunk. The "whizzer" on each speaker beams high frequencies in only one narrow direction. You need real dome tweeters that spread high frequencies all around.

The amplifier power ratings do not say the amount of severely distorted clipping. Most home audio amplifiers have their continuous output power rated at a specified amount of low distortion. A few car amplifier manufacturers correctly say the amount of real low distortion power.
The GM amplifier says 60W x 2 into 4 ohms with the battery charging. It might be 30W with low distortion plus another 30W of distortion power.
The CE102 amplifier says 38W RMS x 2 into 4 ohms with no listed supply voltage and no listed distortion. They say a low distortion number without saying the output power.

The powerful amplifiers will quickly destroy the low power little speakers.

A 12V power supply is not used in a car so maybe you are making the sound system for your home? 12V is with a dead car battery, the power ratings of car amplifiers are when the car battery is charging at 14.4V for much more power.

At 14.4V, both amplifiers at full output into 4 ohm speakers of 200W plus class-AB heating power of another 200W need a 400W power supply that produces (400W/14.4V)= 27.8A. The little 10A power supply does not supply enough voltage and not enough current.
 

MisterBill2

Joined Jan 23, 2018
12,402
At SuperScope the automotive sound packages were rated at 10% Total Harmonic Distortion (THD). That sounds bad but damaged hearing is not able to tell the difference. And the audiophiles complained when their Marantz amp started making 0.1%% THD, saying it sounded so terrible. Different standards, no doubt.
And I am amused when the description of a modern TV mentions the "Giant" 1 3/4 inch woofers for "such clear bass." My first system had 3 inch tweeters!
 

Audioguru again

Joined Oct 21, 2019
4,794
10% distortion sounds bad like acid rock played too loud. 10% distortion frequently burns out people's hearing and tweeters.

An LM3886 hifi amplifier IC with a 56V total supply produces 0.1% maximum distortion from 20Hz to 20kHz at its rated 38W per channel into 8 ohms or 68W per channel into 4 ohm. Its distortion is 0.03% typical at 30W into 8 ohms per channel or 60W into 4 ohms per channel.
 

Thread Starter

doormachine

Joined Jun 15, 2022
6
The small speakers produce NO BASS even the 3.3" one they say "with good bass reproduction". Its datasheet shows no bass for 2.5 octaves of low music frequencies. Most car speakers are much larger at 6.5" in the front doors, 6" x 9" speakers on the rear shelf and a 10" or 12" subwoofer in the trunk. The "whizzer" on each speaker beams high frequencies in only one narrow direction. You need real dome tweeters that spread high frequencies all around.

The amplifier power ratings do not say the amount of severely distorted clipping. Most home audio amplifiers have their continuous output power rated at a specified amount of low distortion. A few car amplifier manufacturers correctly say the amount of real low distortion power.
The GM amplifier says 60W x 2 into 4 ohms with the battery charging. It might be 30W with low distortion plus another 30W of distortion power.
The CE102 amplifier says 38W RMS x 2 into 4 ohms with no listed supply voltage and no listed distortion. They say a low distortion number without saying the output power.

The powerful amplifiers will quickly destroy the low power little speakers.

A 12V power supply is not used in a car so maybe you are making the sound system for your home? 12V is with a dead car battery, the power ratings of car amplifiers are when the car battery is charging at 14.4V for much more power.

At 14.4V, both amplifiers at full output into 4 ohm speakers of 200W plus class-AB heating power of another 200W need a 400W power supply that produces (400W/14.4V)= 27.8A. The little 10A power supply does not supply enough voltage and not enough current.
Do you have any recommendations on speakers happy to go for 4 or 8 ohm? with lower wattage. I have 316 watt power supply, however round 200 watt is used for other components and around 6amps of power left.

I was thinking this Stereo 20W Class D Audio Amplifier - MAX9744, but I am not so sure I can connect the audio board together with it.

Yes, its not to go in a car its to play some background music for a mechanical arcade game, would be good to hear the music with all the noise.

Why does your wiring connect the speakers to the amplifier inputs instead of to the outputs??
Ah I thought low level was better based on this article
 

Audioguru again

Joined Oct 21, 2019
4,794
The Adafruit MAX amplifier produces a little less than the 15W per channel into 4 ohms as common car radios.
There are some good speakers at Parts Express. 4 ohm speakers are used in cars for their higher sound levels than 8 ohm speakers with the 14.2V power supply. Home speakers are alomost always 8 ohms since the home amplifier uses a higher power supply voltage than a car has.

Speakers always connect to the outputs of an amplifier and never are connected to the inputs.
Signal sources that connect to amplifier inputs are almost always line level with RCA connectors.

The article you posted probably thinks that some people want to connect the high level speaker outputs of a factory car radio to the inputs of a high power additional amplifier.
 

Attachments

BobTPH

Joined Jun 5, 2013
5,234
The amp is intended to connect to the speaker outputs if a car radio. It also has line level inputs, which should be used in this application.

Agree with @Audioguru again, the speaker is too small for the amp.

Bob
 

bassbindevil

Joined Jan 23, 2014
457
Consider using a secondhand home stereo (or surround) receiver or PA amplifier, along with a used pair of stereo speakers. Alternatively, powered speakers from a budget brand like Behringer or Monoprice, or whatever is available to you.
 

MisterBill2

Joined Jan 23, 2018
12,402
It may work very well at some lower volume levels, and if the TS has all of the items then give it try.But real speakers rated for the wattage will be required if anything like full power is ever run, presuming another power supply is used.
And real power supplies are available, or can be built. At least I have built a few. The power supplies need adequate hum filtering but they do not require perfect voltage regulation.
 
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Thread Starter

doormachine

Joined Jun 15, 2022
6
parts arrived and connected it up, it has a buzz/hum when audio playing and when not playing, turning the volume (potentiometer) less than half removes the hum/buzz. Potentially a ground loop isolator would fix it? However, since all the parts I connect are either via terminal screws or soldering I don't find any isolators that are without banana/rca plugs, any suggestions?

With the MAX9744 amplifier the audio inputs are not differential, the ground connection is connected directly to the power ground, this chip does not handle differential inputs.

video of buzz/hum
image of wiring diagram

Parts:
Tsunami Super WAV Trigger (Qwiic)
Adafruit 20W Stereo Audio Amplifier - MAX9744
HiVi B3S 3" Speakers
Power Supply (QP-320D)
Adafruit Grand Central M4 Express
 
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Audioguru again

Joined Oct 21, 2019
4,794
"Turning the volume (potentiometer) less than half removes the hum/buzz" Then the noise is coming in the input or you did not use shielded audio cables from the Tsunami to the volume control and from the volume control to the amplifier inputs. The metal housing on the volume control should connect to 0V. Maybe the amplifier board needs to be shielded inside a metal box connected to 0V.

The buzz is not from 50Hz or 60Hz electrical pickup. Instead it is a square wave, triangle wave or sawtooth wave at 680Hz which is probably produced by the Tsunami board beating with the amplifier's class-D switching frequency.
 

Thread Starter

doormachine

Joined Jun 15, 2022
6
sorry, after putting ears closer its still present but very faint when less than half, attached image of the volume knob. I'll look into the 0V thing.

I ended up trying another audio source, mobile and a laptop just connected from battery and played some audio and its clear, no hum/buzz. When connecting the AUX cable to the PC is when the hum/buzz starts so I thought because the PC is on a different wall outlet I'd connect it to the power board with the other devices using a three prong cable, that didn't work.

I am using this 3.5mm AUX audio cable, from the looks its not shielded and it doesn't state anywhere that it is.
 

Attachments

Audioguru again

Joined Oct 21, 2019
4,794
The 680Hz buzz either comes from the pc or it is a high frequency from the pc that beats with the high frequency of the class-D switching amplifier. 680Hz and its 3rd harmonic has nothing to do with the 50Hz or 60Hz from a wall outlet.

A 3.5mm to 3.5mm cable might not be shielded then it will pick up interference.
 

MisterBill2

Joined Jan 23, 2018
12,402
It may be that the 3.5mm connection of the PC is only intended to feed headphones and that it is not tied to a "grounded" common. That is reasonable, because headphones are isolated from everything else. The only hope there is true galvanic isolation of all three conductors.
But if the rest of the system picks up the buzz before even connecting, it also means that the input you are using does not have an adequate common connection. So there is both a buzz supply and a buzz receiver situation. The common terminal of the 3.5mm connection may not be adequately bypassed to the input section ground (common). So there may be more than one problem. OR that shielded cable might not really be shielded.
 

Audioguru again

Joined Oct 21, 2019
4,794
I measured the buzz again and it is a 675Hz square wave, not 680Hz. The buzz includes a low frequency fluttering square wave of about 10Hz.

Since bringing the shielded cable tip near but not touching the pc causes the buzz then I think it is a high frequency interference "sprayed" out of the pc and it is probably beating with the 255kHz to 410kHz Class-D switching frequency of the MAX9744 Amplifier.
 
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