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AptX Bluetooth (TX/RX) and 2.4Ghx Wireless... low latency guitar to low latency Bluetooth Headphones

McDMcD
edited November 2020 in App Tips and Tricks

I need to learn the trick to measure latency from source to headphones... any apps and set up appreciated.

But I got 2 Bluetooth AptX devices today and I got the Transmitt/Receive hardware for the guitar a few months ago.

The latency is low enough I asked my wife to test it for she played the guitar and keyboard for over an hour using the new headphones and she never does that. Her first words were "there's a little delay" but she quickly just adapted. I suspect the delay in in the 10-20 msec range but I'd like to measure it. When she played the iPad was 15 feet away from her.

Here's the hardware for the guitar to iPad (using AUM with TH-U for an amp/rig) to wireless headphones:

TX/RX for Guitar to Audio Interface:

Smallest/Cheapest 1/4" Audio interface using Lightning input using a Camera Kit Adapter:

Heaphone to Bluetooth AptX (low latency):

Cheapest AptX capable headphones:

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Comments

  • Looking forward to hear about your findings.
    Additional latency both in and out..? 🤭🤞
    Also curious if there is significant signal degradation in or out.

  • @0tolerance4silence said:
    Looking forward to hear about your findings.
    Additional latency both in and out..?

    IN: Latency in is excellent... I'm sure you've seen guitarists walking around the stage without
    cabling to their amps. This is that type of wireless.

    OUT: You know bluetooth from the iPad/Iphone is useless for audio. BUT AptX is a
    Bluetooth profile designed with low latency and it's OK. It's useful. But you need to adapt
    one of the usual audio outs using a device like the one I got today.

    Also curious if there is significant signal degradation in or out.

    No the signal paths are all digital wit the except of the A-to-D in the iRig HD and the
    D-to-A inside the iPad/iPhone to drive the headphone port and the D-to-A in the headphones.

    I hate cables... whenever I connect a guitar or headphones to the iPad I risk pulling it onto the floor.

  • Step up and get yourself an in ear stage monitor system. $500 will do ya. ;)

  • @McD said:

    @0tolerance4silence said:
    Looking forward to hear about your findings.
    Additional latency both in and out..?

    IN: Latency in is excellent... I'm sure you've seen guitarists walking around the stage without
    cabling to their amps. This is that type of wireless.

    OUT: You know bluetooth from the iPad/Iphone is useless for audio. BUT AptX is a
    Bluetooth profile designed with low latency and it's OK. It's useful. But you need to adapt
    one of the usual audio outs using a device like the one I got today.

    Also curious if there is significant signal degradation in or out.

    No the signal paths are all digital wit the except of the A-to-D in the iRig HD and the
    D-to-A inside the iPad/iPhone to drive the headphone port and the D-to-A in the headphones.

    I hate cables... whenever I connect a guitar or headphones to the iPad I risk pulling it onto the floor.

    While there won’t be degradation of the encoded signal, are you sure they aren’t using a lossy codec that doesn’t degrade the signal when encoded?

  • @McD said:

    @0tolerance4silence said:
    Looking forward to hear about your findings.
    Additional latency both in and out..?

    IN: Latency in is excellent... I'm sure you've seen guitarists walking around the stage without
    cabling to their amps. This is that type of wireless.

    OUT: You know bluetooth from the iPad/Iphone is useless for audio. BUT AptX is a
    Bluetooth profile designed with low latency and it's OK. It's useful. But you need to adapt
    one of the usual audio outs using a device like the one I got today.

    Also curious if there is significant signal degradation in or out.

    No the signal paths are all digital wit the except of the A-to-D in the iRig HD and the
    D-to-A inside the iPad/iPhone to drive the headphone port and the D-to-A in the headphones.

    I hate cables... whenever I connect a guitar or headphones to the iPad I risk pulling it onto the floor.

    That’s nice! I’ll have to try that guitar in. Do you know how long will the battery hold / it takes to recharge?

  • @espiegel123 said:
    While there won’t be degradation of the encoded signal, are you sure they aren’t using a lossy codec that doesn’t degrade the signal when encoded?

    I just opened these presents today... try NOT to ruin it for me on the first day.

    It sounds good but YMMV. It will cost a bit to assemble the pieces. About ~$300 for me counting in the CCK. But many here have a lot of these pieces already.

    It's also possible to use a 2nd pair 2.4GHz TX/RX for both the Input cable replacement and the headphone cable replacement when the headphones have a 1/4" input port. Converting
    headphone to 1/4" is a bit ugly for me.

    For headphones with a 1/8th inch mini-plug port a second AptX Bluetooth adapter could be
    used since they have a TX and RX switch and can be paired to each other (I suspect).

  • I just learned that Mac OS supports AptX... not sure yet how I can benefit from that yet.
    Maybe IDAM from my IOS devices will let me use multiple IOS devices through the Mac
    to my AptX headphones.

  • I’ve got the Donner guitar wireless - they were $99 and work well with my acoustic electric which has active electronics in it (which can be a problem for those wireless systems sometimes). Only used it in a live setting a few times, with iOS it worked pretty well with nearly no latency on that side as well. Takes about 5 hours to charge and I think you get about the same amount in wireless time. Sounds like it is a fun time with some new presents @McD .

    Curious to see which apps you are using with the Bluetooth headphones.

  • Does the signal get compressed, which I presume it would, and how does it compare with complex sounds to the same signal via a cable.

  • edited November 2020

    I've been using these arctic steel 7 wireless headphones for a few years now and can highly recommend them for very low latency wireless IOS music making. I stick a battery on the transmitter, so it's just a 3.5mm headphone cable to my audio interface.

    https://steelseries.com/gaming-headsets/arctis-7?gclid=Cj0KCQiAwMP9BRCzARIsAPWTJ_EPnnmtar3wFD238dI4fNBh463epZ5idOWUHbsWYelTmOGAouLZJZ0aAk8yEALw_wcB

    I pair these headphones with Xvive U2 wireless guitar (via my iOS device and interface), since I've been playing with this combo I've stopped looking for other solutions. @McD that's not to devalue your new setup in any way, just reporting what I've found to be good for the job. I get a couple of hours charge from the Xvive jacks, days from the headphones.

    Sounds as good as my wired headphones, except I'm in a better mood because I'm not tripping over any cables.

  • @McD To measure latency:
    Put your headphones right next to the guitar strings, crank up their volume to the max.
    Put a recorder or just your iPhone close to both and give a muted high string a short pick.
    I'm usually recording with TwistedWave on iPhone because it allows me to zoom in and read the time between the two transients.

  • edited November 2020

    Do these transmitters have a slight audible noise (from AD/DA and preamps)? Does the sound change when increasing the distance?
    What's the max. distance?

  • @steve99 said:
    I've been using these arctic steel 7 wireless headphones for a few years now and can highly recommend them for very low latency wireless IOS music making. I stick a battery on the transmitter, so it's just a 3.5mm headphone cable to my audio interface.

    https://steelseries.com/gaming-headsets/arctis-7?gclid=Cj0KCQiAwMP9BRCzARIsAPWTJ_EPnnmtar3wFD238dI4fNBh463epZ5idOWUHbsWYelTmOGAouLZJZ0aAk8yEALw_wcB

    I pair these headphones with Xvive U2 wireless guitar (via my iOS device and interface), since I've been playing with this combo I've stopped looking for other solutions. @McD that's not to devalue your new setup in any way, just reporting what I've found to be good for the job. I get a couple of hours charge from the Xvive jacks, days from the headphones.

    Sounds as good as my wired headphones, except I'm in a better mood because I'm not tripping over any cables.

    I'll bet that would drop the latency a bit more to use 2.4GHz wireless vs Bluetooth.

  • @rs2000 said:
    @McD To measure latency:
    Put your headphones right next to the guitar strings, crank up their volume to the max.
    Put a recorder or just your iPhone close to both and give a muted high string a short pick.
    I'm usually recording with TwistedWave on iPhone because it allows me to zoom in and read the time between the two transients.

    I'll try it and see what apps I have that show timing details.

  • @rs2000 said:
    Do these transmitters have a slight audible noise (from AD/DA and preamps)? Does the sound change when increasing the distance?
    What's the max. distance?

    I didn't notice any noise being added. But I wasn't listening critically so I need to do more testing.

    I find Bluetooth can travel pretty far unless there are too many walls blocking the signal.
    I have a dead spot just where I reach the commode for example. So, I need to have it moved forward 12 inches.

  • @McD said:

    @rs2000 said:
    @McD To measure latency:
    Put your headphones right next to the guitar strings, crank up their volume to the max.
    Put a recorder or just your iPhone close to both and give a muted high string a short pick.
    I'm usually recording with TwistedWave on iPhone because it allows me to zoom in and read the time between the two transients.

    I'll try it and see what apps I have that show timing details.

    TwistedWave Recorder is free. It can't do much but it can record, zoom and show a millisecond timeline.

  • edited November 2020

    .

  • @rs2000 said:
    TwistedWave Recorder is free. It can't do much but it can record, zoom and show a millisecond timeline.

    Awesome... I knew you'd have the right advice to measure this. I'm also changing my guess from
    10-20 msec to something more logical like 100-200 milliseconds. I was think 10 ms is 1/10 of a second but that's just mental deterioration I suspect. My wife thinks I'm slipping but I know she is so she's hardly a good judge. We can see a movie and 3 months later she says we need to see that. Mostly with movies that are less than memorable like "Kong Island".

  • I just refined my most minimal wireless rig so far, thought I’d share. Wireless guitar (out of pic with Xive U2), wireless headphones (Arctis 7). Then Launchpad X and audio interface into 2xUSB cck. Homemade Bluetooth knob controller and (out of pic) Bluetooth foot controller.

    I stuffed all the innards into a nice wooden box, Wireless guitar receiver, vox audio i/o guitar interface, usb hub, usb battery and headphone transmitter. Just the usb cable from hub emerging and connecting to CCK. 8 years of engineering to get this uncluttered :)


  • My testing indicates 3 areas of latency:
    The iPad itself adds ~20 msec (the only app in the path is TW Recorder which is free)
    The 2.4Ghz TX/RX pair I use added about 6 msec
    The AptX Transmitter to AptX Bluetooth headset adds 45 msec
    With all three I get total latency around 70 msec.
    I'm interested in replacing the AptX link with another 2.4Ghz wireless TX/RX pair or
    "Gaming Headphones" that use the 2.4Ghz spectrum.

  • @McD said:
    My testing indicates 3 areas of latency:
    The iPad itself adds ~20 msec (the only app in the path is TW Recorder which is free)
    The 2.4Ghz TX/RX pair I use added about 6 msec
    The AptX Transmitter to AptX Bluetooth headset adds 45 msec
    With all three I get total latency around 70 msec.
    I'm interested in replacing the AptX link with another 2.4Ghz wireless TX/RX pair or
    "Gaming Headphones" that use the 2.4Ghz spectrum.

    That’s a lot just from the iPad - what sampling rate is that (how much difference does that make) and what do you get from different buffer sizes (in Overloud for example)?

    Are you finding that 20ms (+6 from the guitar) a problem or is that in the acceptable zone? Sometimes I get noticeable delay on starting apps, replugging the interface generally sorts it out (never remembering to prepare myself for feedback).

  • @steve99 said:

    @McD said:
    My testing indicates 3 areas of latency:
    The iPad itself adds ~20 msec (the only app in the path is TW Recorder which is free)
    The 2.4Ghz TX/RX pair I use added about 6 msec
    The AptX Transmitter to AptX Bluetooth headset adds 45 msec
    With all three I get total latency around 70 msec.
    I'm interested in replacing the AptX link with another 2.4Ghz wireless TX/RX pair or
    "Gaming Headphones" that use the 2.4Ghz spectrum.

    That’s a lot just from the iPad - what sampling rate is that (how much difference does that make) and what do you get from different buffer sizes (in Overloud for example)?

    Are you finding that 20ms (+6 from the guitar) a problem or is that in the acceptable zone? Sometimes I get noticeable delay on starting apps, replugging the interface generally sorts it out (never remembering to prepare myself for feedback).

    Sample rate should impact latency, but buffer size will.

    @McD : 20ms sounds like a lot from the iPad alone. How sure are you of that? What buffer size? What was your setup?

  • FWIW, latency added by a 256 sample buffer is 5.8 ms

  • @McD said:
    My testing indicates 3 areas of latency:
    The iPad itself adds ~20 msec (the only app in the path is TW Recorder which is free)
    The 2.4Ghz TX/RX pair I use added about 6 msec
    The AptX Transmitter to AptX Bluetooth headset adds 45 msec
    With all three I get total latency around 70 msec.
    I'm interested in replacing the AptX link with another 2.4Ghz wireless TX/RX pair or
    "Gaming Headphones" that use the 2.4Ghz spectrum.

    Thank you!
    These 6ms over 2.4Ghz sound interesting, given the audio quality is good.
    Maybe there are comparable products for stereo audio?

    Gaming headphones is another useful tip 😊

  • @McD : 20ms sounds like a lot from the iPad alone. How sure are you of that?

    It would be nice to have others use TW Reader and test their input to headphone latency.
    The iPad only case includes the iRig HD which has an internal A-to-D since it's output is USB.
    So, some latency would be added there.

    I swapped out the iRig HD for a Zoom U-422 and some of the results changed but I had to call off.

    My approach is to create an impulse input by clicking 2 drum sticks together about 2 inches from the mic with the mic inserted into the earphone port of the headphones. Anyone with a mic (tho' testing with the iPad/iPhone mic is useful data) and headphones can play and maybe we can get some reproducible numbers for various devices.

    I expect the 2.4GHz devices will produce lower latencies.

    I'm going to do a little Google searching on acceptable latency for guitarists. I'm sure
    soem guitarists will insist on very low latencies and some will consider that they have learned to
    adapt since they often deal with latencies of their stage situations and have to adapt and pick early to have the sound arrive "in the pocket".

    The human input system to the brain also has latencies but I'm getting... "Squirrel!"

  • Where is the default buffer size set for an iPad running TW Reader?

  • @McD said:
    @McD : 20ms sounds like a lot from the iPad alone. How sure are you of that?

    It would be nice to have others use TW Reader and test their input to headphone latency.
    The iPad only case includes the iRig HD which has an internal A-to-D since it's output is USB.
    So, some latency would be added there.

    I swapped out the iRig HD for a Zoom U-422 and some of the results changed but I had to call off.

    My approach is to create an impulse input by clicking 2 drum sticks together about 2 inches from the mic with the mic inserted into the earphone port of the headphones. Anyone with a mic (tho' testing with the iPad/iPhone mic is useful data) and headphones can play and maybe we can get some reproducible numbers for various devices.

    I expect the 2.4GHz devices will produce lower latencies.

    I'm going to do a little Google searching on acceptable latency for guitarists. I'm sure
    soem guitarists will insist on very low latencies and some will consider that they have learned to
    adapt since they often deal with latencies of their stage situations and have to adapt and pick early to have the sound arrive "in the pocket".

    The human input system to the brain also has latencies but I'm getting... "Squirrel!"

    I still don't understand how you are testing the latency.

    You click the drumsticks together and record from a mic inserted in the earphones. What are you comparing it to?

    How are you determining the time between when the sticks are clicked and when the sound comes back out of your headphones?

  • @espiegel123 said:
    How are you determining the time between when the sticks are clicked and when the sound comes back out of your headphones?

    @rs2000 slipped me the clue on this.

    TW Reader can record from various inputs.

    1. Press record and a "Monitor" icon shows up in the lower left. Click on that and select your hardware audio input. The iPad/iPhone Mics (I have 3 apparently - front, back, top). For a while I was testing with the iPad mic and not learning much.
    2. I started with a guitar as the input device but the "impulse" was so spread it was hard to tell where the "echo" started... I was just a line of low volume transients. Which one was my "echo" of the input... I almost quit.
    3. As I dug up a microphone and an adapter I have that converts XLR male to 1/4" phono female. Then I ran a typical guitar cable into the iRig HD for the "no wireless" cabled starting point.
    4. I tried using vocal pops but the volumes and echo were terry meaningless. So, I started clicking the drum sticks and there seemed to be a tiny echo out there. I need to amplify the signal to the headphones so a added a parallel AUM path and got a nice echo but I wondered if these results wouldn't add the latency of the AUM path processing to skew the results. So, I scrapped the AUM path for a single instance of TW Reader and inserted the mic into the ear socket of the headphones. Better...

    So... what you'll see in TW Reader is a huge impulse of a click or hand clap or finger snap. Any very short loud pulse will do. Then you want to measure (by zooming in) the distance to the start of the recorded headphone "echo" which has the same path to TW Reader as the original impulse. TW Reader has "audio selector" controls and it displays precise timing details for the selected audio segment in the upper right corner using 0.000 second levels of accuracy. So, I would see echo ranges in the 0.028 range.... 28 milli-seconds.

    It's a perfect tool with the one caveat... You can addict the gain of the input and w simple way to add gain would be a nice addition to the testing process. I suspect there are apps and I tried to use AudioBus which allows TW Reader to be an output so I could insert an amplifier but there were bugs and that failed to help.

    Any additional suggestions of apps and procedures appreciated.

    Please test my procedure and report any latencies for any path using any commercial hardware.

    I'd love to have those 2.4GHz "Gaming Headphones" to test (and use for a more comfortable headphone over the BT One AptX product). BT One is cheap but not comfortable for hours of
    playing on a walk. The 2.4Ghz transmitter for the Gaming headphones also looks like a good device to velcro to my Telecaster next to my iPhone 5S. For the iPad use case I could velcro the device to the iPad cover (or another cover suitable for my wireless practice sessions).

    I have an old iPad 1 that runs Amp One and I could even use that for situations where it might rain... less risk. Amp One holds up as a nice Amp Sim... but you had to buy it years ago to use it now. It's gone from the store except for re-loads by valid owners.

  • @McD said:

    @espiegel123 said:
    How are you determining the time between when the sticks are clicked and when the sound comes back out of your headphones?

    @rs2000 slipped me the clue on this.

    TW Reader can record from various inputs.

    1. Press record and a "Monitor" icon shows up in the lower left. Click on that and select your hardware audio input. The iPad/iPhone Mics (I have 3 apparently - front, back, top). For a while I was testing with the iPad mic and not learning much.
    2. I started with a guitar as the input device but the "impulse" was so spread it was hard to tell where the "echo" started... I was just a line of low volume transients. Which one was my "echo" of the input... I almost quit.
    3. As I dug up a microphone and an adapter I have that converts XLR male to 1/4" phono female. Then I ran a typical guitar cable into the iRig HD for the "no wireless" cabled starting point.
    4. I tried using vocal pops but the volumes and echo were terry meaningless. So, I started clicking the drum sticks and there seemed to be a tiny echo out there. I need to amplify the signal to the headphones so a added a parallel AUM path and got a nice echo but I wondered if these results wouldn't add the latency of the AUM path processing to skew the results. So, I scrapped the AUM path for a single instance of TW Reader and inserted the mic into the ear socket of the headphones. Better...

    So... what you'll see in TW Reader is a huge impulse of a click or hand clap or finger snap. Any very short loud pulse will do. Then you want to measure (by zooming in) the distance to the start of the recorded headphone "echo" which has the same path to TW Reader as the original impulse. TW Reader has "audio selector" controls and it displays precise timing details for the selected audio segment in the upper right corner using 0.000 second levels of accuracy. So, I would see echo ranges in the 0.028 range.... 28 milli-seconds.

    It's a perfect tool with the one caveat... You can addict the gain of the input and w simple way to add gain would be a nice addition to the testing process. I suspect there are apps and I tried to use AudioBus which allows TW Reader to be an output so I could insert an amplifier but there were bugs and that failed to help.

    Any additional suggestions of apps and procedures appreciated.

    Please test my procedure and report any latencies for any path using any commercial hardware.

    I'd love to have those 2.4GHz "Gaming Headphones" to test (and use for a more comfortable headphone over the BT One AptX product). BT One is cheap but not comfortable for hours of
    playing on a walk. The 2.4Ghz transmitter for the Gaming headphones also looks like a good device to velcro to my Telecaster next to my iPhone 5S. For the iPad use case I could velcro the device to the iPad cover (or another cover suitable for my wireless practice sessions).

    I have an old iPad 1 that runs Amp One and I could even use that for situations where it might rain... less risk. Amp One holds up as a nice Amp Sim... but you had to buy it years ago to use it now. It's gone from the store except for re-loads by valid owners.

    What size buffer were you using?

    I wonder if you get double the latency -- I am not sure if the buffers are there on both input and output. If they are, your return trip passes through the buffer on the way to the headphones and then on the way back in.

    A better way to measure the latency native to the device would be to use an audio interface that has loop back. You could record the playing of an impulse and its return in AUM.

    I see that there is an app that someone put together for that:

    https://onyx3.com/LatencyMeter/

    Re acceptable latency for guitar. I think it depends a lot on the person. With an amp sim, setting the buffer larger than 256 results in latency that I find irritating. But at 256, it doesn't bother me. If I add brusfri (which adds only a little bit extra), it irritates me. I am sure I could get used to it. (Heck drummers have to get used to the latency differences between the hi-hat and kick pedals -- they may not even realize that they do it. When using MIDI guitar, the added latency of the MIDI tracking doesn't bother me (even though it is probably worse than Brusfri's) -- but some find it intolerable. Some find the 256 buffer that I tolerate unusable. And some people don't mind a buffer of 1024.

  • A $10 investment in LatencyMeter could be useful to evaluate the 2.4Ghz TX/RX pair compared to a straight loopback cable and to verify my assumptions about TE Reader's echos. I'll think about it since I have $47.13 in credit and but Black Friday is only 11 days away.
    Latency Meter won't help me with the AptX headphones... wait... there might be a way to test that too. If I don't find it useful I could request a refund. And $10 is my impulse limit.

    Should I keep testing? or let someone else take the baton? Bueller? Godot? @rs2000?

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