Phone to PA audio prob...

[HTB]

Hi all. Using Samsung a21s to run audio cue app playing .wav drum tracks through 3.5mm stereo headphone output socket to PA for backing. Audio quality is fine when playing back tracks, but clicks are present before track runs & after track stops. Clicks are audible at same level regardless of phone audio output level…I assume clicks being generated by phone? Weird thing is that if headphones (Beyer DT990) are plugged into phone, clicks are not present at all. Sooo, tried new set-up - audio output from phone into Klark-Teknik DI 22P via Van Damme lead, balanced out from DI via XLR to PA - clicks still present. Why the clicks present through new connection to PA, but not present when headphones used? - I feel the solution is somewhere in that last sentence. Any thoughts would be very welcome, as I’m pulling my hair out over this.

[sonics]

Have you tried playing them with a different playback app, or the built-in audio player? Do you still get the clicks?

Also, try adding a very short fade in and out to the files. Any difference with any of the playback apps?

[Hugh Robjohns]

^ all of those things first.

Another thought is that the line input and DI are both very high impedance, whereas the headphones are low impedance – and that difference might possibly affect the output amp and its switching clicks.

If you have suitable leads/adapters it might be worth trying the phone feeding a (low impedance) mic input — but make sure phantom is off and start with preamp gain and replay volume at minimum.

[shufflebeat]

Bluetooth?

[Sam Spoons]

Are you connecting to the PA via two channels or summing the output to one? If the latter are you using a proper summing lead or one with the outputs simply shorted?

[HTB]

Have you tried playing them with a different playback app, or the built-in audio player? Do you still get the clicks?

Also, try adding a very short fade in and out to the files. Any difference with any of the playback apps?

Thanks for your input!
The clicks are there with different apps & the audio player, significantly the clicks are there even with the phone volume completely off. Tried the apps with zero count-in, and also tried loading a .wav with a quick fade in - no difference. It's not to do with the audio itself, or the apps - the clicks seem to be generated by the phone itself...the mystery is, why aren't the clicks present when using headphones direct from the phone?

[HTB]

^ all of those things first.

Another thought is that the line input and DI are both very high impedance, whereas the headphones are low impedance – and that difference might possibly affect the output amp and its switching clicks.

If you have suitable leads/adapters it might be worth trying the phone feeding a (low impedance) mic input — but make sure phantom is off and start with preamp gain and replay volume at minimum.

Thanks for your reply!
The difference in impedance is something that occurred to me...trouble is, I don't have the required lead to try your suggestion, & it can become an expensive game! I'm certain the clicks are being generated by actions within the phone - my next lead (to be made up) will be 3.5mm mini jack to pair RCAs (the DI has inputs for RCAs) via star quad cable, connected as a pseudo balanced lead...don't even know if it's possible?

[HTB]

Bluetooth?

Thanks for your reply!
Even if bluetooth eliminated the clicks, I wouldn't feel comfortable using it in a live gig situation due to unreliability / interference probs.

[HTB]

Are you connecting to the PA via two channels or summing the output to one? If the latter are you using a proper summing lead or one with the outputs simply shorted?

Thanks for your response!
Via one or both channels, but not summed. Either way, same prob.

[James Perrett]

Can you post a picture of the cable that you are using somewhere?

(This forum doesn't host pictures so you will have to post them elsewhere and link to them).

[sonics]

I'm no cellphone expert, but I believe that many modern phones detect the device impedance, and then switch the output level circuit to match or some such magic. It sounds related to that mechanism. Maybe the detection is done when playback begins, and is causing the click?

[adamburgess]

I know that my old MacBook Pro (2012) used to put the headphone out to sleep if not used for a while, and that would involve a tiny click sometimes when restarting audio. Maybe something similar with the phone?

I've never used the headphone jack on anything for years, so don't know if it was a hardware thing, or something that is fixable over software by keeping the output alert… Energy saving gone mad

[BigRedX]

Are you sure that the phone playback system isn't doing any conversion to your audio files before playing them back?

My first smartphone was a Samsung (despite being an Apple user for everything else) and the app I was recommended for syncing with iTunes put clicks at the beginning of every audio file I imported. I couldn't find any way of preventing this and ended up having to revert back to my iPod for listening to music and use my phone just for making phone calls.

[Dave Rowles]

A cable is better, but I've used bluetooth in stage audio situations before and it's not let me down. Even using a consume Logitech bluetooth receiver. I'll admit that I wouldn't use bluetooth on a big gig with a big rig but on smaller gigs there's really no reason not to.

Normally to connect a phone to a PA system I'll generally use a 3.5mm -> Dual RCA into a suitable RCA input on a desk. If the desk doesn't have that, I'll break out the neutrik RCA->XLR adapters that I have. I did have a dedicated 3.5mm->Dual XLR cable at one point that I soldered together myself, but left it at a gig somewhere in Europe....

Have you turned off haptics and keyboard click noises in the settings?

[HTB]

Thank you everyone for your responses - have finally solved what was a most frustrating problem...had a lead made up - 3.5mm mini jack to a pair of 1/4" mono jack plugs...each jack plug had a 270R resistor wired across the live & earth terminals to fool the phone into 'seeing' a resistance similar to headphones. When the phone putput was previously fed to much higher resistance than it was expecting to see, each time the audio was switched on & off, it was making a DC level shift to try to compensate for the discrepancy. With the dummy load that it now sees, it makes zero adjustments, & therefore does not generate any clicks. Phew!

[Hugh Robjohns]

[HTB]

Both Mr. Robjohns & Sonics were on the money there - impedance can be a funny old thing - thanks chaps!

[sonics]

Glad you got a solution.

Now I'll have to make up another "special" cable for my toolkit!