BIAS FX for Ipad pro lower latency



  • Hi,
    I got a 2017 ipad pro and I'm using Bias Fx with amplifiers exported from Bias Amp. As interface I'm using an iRig HD2 . On Bias Fx I have very basic setup, just one amp with a boost and a mod pedal and cpu always stays under 25% load . I connect output direcly to the mixer using a RCA cable. I'm alway using a ultra low latency setting but I can hear latency while playing, expecially with clean sounds.
    My questions are:

    • It there any way to set audio buffer size to try lower latency?
    • What's the audio buffer size of ultra low latency mode?
    • Ipad pro is reasonably powerfull why don't try to lower latency? I still have about 70% free cpu power.
    • Could it be possible to have in Bias FX for IOS (and also on Bias Amp2) a panel like the desktop version where I can set buffer size and sample rate to lower the latency?

    I'm really enjoying this app, it's the first app very responsive so close to a real amp but this latency is really frustrating. I mean it's usable but i always hear latency.

    Thanks in advance


  • A2

    I did a test a ways back, and not 100% positive if I put it on my webiste or not, but the iRig HD2 on ios ended up around 20msec RTL minimum



  • Hi,
    Did you try to measure RTL when output is sent to ipad speaker (so I can use headphones) ? I mean using AD from iRig HD2 but DA from ipad.
    Do you know if there any interface under 10msec? I mean, on early 2000s i used to have a 3-5msec latency on my pc with a consumer terratec sound card on cubase...


  • A2

    I didnt test any to the speaker. I guess I could ,but since on stage it would have needed to get to an output, I tested from each interface's actual output jack. Some of these devices are capable of ok RTL on computers but not as far as I could figure, on ipads


  • A2

    The interfaces tried were the StudioJack Mini from Sonoma Wire Works which I will abbreviate as "SJM" and the iRig HD2 from IK Multimedia, which I will abbreviate to "HD2"

    I started with Audiobus 3 with system audio input as input and system audio output as output, to establish, what as far as I can tell would be a baseline round trip latency measurment

    Audiobus 3 64 frames: SJM 14, HD2 16
    Audiobus 3 256 frames: SJM 26, HD2 25

    BiasFX Ultralow Latency, all FX bypassed: SJM 15, HD2 19
    BiasFX normal Latency, all FX bypassed: SJM 21, HD2 25
    BiasFX Ultralow Latency, Amp, Drive and EQ on : SJM 15, HD2 20

    Bias Amp Low Latency: SJM 21 , HD2 25

    I think there are a few conclusions to draw from this, assuming my testing is correct.

    In low latencies, the SJM performs far better than the HD2, at 256 frames (if my desktop knowledge is anything to draw upon), whatever hidden safety buffers the HD2 uses seem to be bypassed, while their presence is most certainly felt at lower latencies.

    Bias FX seems to add zero to negligible latency. Fruther testing with what often are latent fx (EQ, and an amp with a baked in impulse) do not seem to add to this latency. (if so, KILLER job with the DSP at Positive Grid!)

    Bias Amp seems quite a bit more latent than Bias FX



  • That's a shame. We definitely need more tweaking on ipads.



  • Support answered Ultralow Latency buffer in BiasFX Universal is fixed at 128. From your tests looks like Bias Amp 2 buffer in low latency could be set at 256. It would be great to be able to set BiasFX and Bias Amp2 buffer to 64 or even 32.



  • I've tried to use Bias FX using AD from iRig HD2 but DA from ipad but I haven't noticed any latency improvement.


  • A2

    I'm more concerned about the other 10 or so miliseconds that are getting munched past the buffer.

    128 samples is possibly as low as 6 miliseconds RTL...theres at least another 8 to play with there!



  • @felix @Mike As an iPad Pro user I'd like a 64 buffer option. I know there is a cost associated with this because you will have noobs trying to turn the 'hyper' low latency mode on their three generations old iPad and then asking support why their audio is crackling, but I have an Apogee Jam+ and 2018 iPad Pro 11". This thing is crazy fast, I'm sure it could run at 96 or 64 without glitches. Maybe if you are on Pro or newer Air is could be detected and another setting added.

    Also, something to keep in mind for Bias Fx 2 on iOS which would hopefully follow the desktop release like Amp 2 did, maybe the buffering could be more configurable on iOS. I have interfaces with multiple outputs too.