44.1khz master only SPDIF, latency and the Kemper

  • Was reading a Sound on Sound article and came across this interesting line: "For instance, in the case of a typical ASIO buffer size of 256 samples in a 44.1kHz project, latency is 256/44100, or 5.8ms, normally rounded to 6ms. Similarly, a 256-sample buffer in a 96kHz project would provide 256/96000, or 2.6ms latency."


    This interested me greatly, because my PC is not really souped up and I've been forced to use higher buffer settings in order to avoid dropouts.


    I know we've discussed the merits and demerits of the Kemper's SPDIF "master only" policy with 44.1 khz and I understand the logic behind the decision. That said, given that recording in higher sample rate does offer the benefit of reduced latency, perhaps this is one other facet that I feel should have been taken into consideration while deciding the sampling rate.


    Thoughts, anybody?

  • correct me if I'm wrong (and this might be the case here) but I always thought the higher the sample rate the more cpu usage. So if that's right a higher sample rate wont save you from dropouts you otherwise get from a lower buffersize.
    And these days most machines can handle a lower buffersize .... if you're not using 20 instances of your plug ins on every channel while tracking ;)


  • We could have a option for this in the system menu, faster is bether. if you dont want all the fx on and just use it as an amp I think this is possible.

  • 256 samples is the default value for many interfaces, but with a well configured DAW you can easily go way below this default value. My DAW for example is running at 48kHz and the audio interface is set to 32 samples buffer, no issues.


    Regarding your PC ... I'm not sure you would have success using 96kHz with 256 samples buffer, because that would mean you can use 44.1kHz with 128 samples buffer as well. Or the other way round ... if you NEED to use 256 samples with 44.1kHz, then you would need to set the buffer to at least 512 samples when switching to 96kHz. ;)


    Also keep in mind that DAWs should be able to automatically (or through custom setting) compensate for latency. So I don't think, latency is a reason to go for 96kHz. The only reason for using 96kHz I can think of is that you can slow down audio footage without compromising the audible frequency spectrum (Nyquist). A rare use case for most, but in audio effects world this CAN be helpful sometimes. Record an explosion and slow down the "BANG" to make it more "BOOM" without loosing the higher parts of the recorded frequency spectrum. Very theoretical example, I know. Difficult to record usable frequencies beyond 20kHz with common microphones and pre-amps. But I think it serves well for explanation.
    96kHz is a rarely required sample frequency ... 48kHz is a different story for different reasons though.

  • "For instance, in the case of a typical ASIO buffer size of 256 samples in a 44.1kHz project, latency is 256/44100, or 5.8ms, normally rounded to 6ms. Similarly, a 256-sample buffer in a 96kHz project would provide 256/96000, or 2.6ms latency."


    This conclusion can be misleading. A 128-sample buffer in a 44.1kHz project also has 2.6ms latency. Typically, ASIO buffers are 64 or 128 today. This increases the "stress" for the system since it increases the overhead that comes with the buffer handling (not the audio rendering).


    Nevertheless, even if the buffer size is 128-samples, usually bus and driver handling can add multiple buffers, since jittering or even out-of-order data need to be intercepted with multiple buffers.


    Since the overhead of handling small buffer sizes is quite a number, VST/AU hosts usually render one track only, the "selected" track or the ones that are recording. All other tracks are rendered with larger buffer sizes (and "not so" realtime), but since the musician does not interact with them, he/she doesn't notice it.

  • correct me if I'm wrong (and this might be the case here) but I always thought the higher the sample rate the more cpu usage. So if that's right a higher sample rate wont save you from dropouts you otherwise get from a lower buffersize.
    And these days most machines can handle a lower buffersize .... if you're not using 20 instances of your plug ins on every channel while tracking ;)


    I recently purchased a crossgrade of Magix Samplitude Pro X for my PC. When I ran the software with my regular settings, I almost immediately ran into audio problems in the form of Lost Audio Buffers (LABs). Had to change a variety of settings to have acceptable recording performance with no LABs. But this also involved raising my audio buffer to 1,048 samples, the maximum possible with my Fireface 800 interface.


    My PC isn't the greatest, but it's not chopped liver either. Some basic specs:
    Inter I5-2500K processor
    Asus P7-H55M motherboard
    8 GB Corsair DDR3 RAM
    Samsung SSD
    Seagate 500 GB hard disk
    Western Digital 320 GB hard disk
    VIA Firewire card
    Windows 8.1


    The weak link seems to be my motherboard, but I don't have cash to upgrade at the moment. I ran some tests with latencymon and found that my computer would function with around 350 DPC latency on average, but every once in a while, it would spike to 500 us DPC. Consequently, I was getting a lot of audio dropouts and had to really put extreme settings to get things in order.


    I don't have this problem with Cubase 6.5, but I migrated to Samplitude because I prefer the "sound" (entirely subjective, but I'd say it has a more open and neutral character), as well as the fact that midi quantization is less of a pain than in Cubase (weird but true, I need it for my choppy drum playing :D).


    Due to the 1024 buffer setting, I'm experiencing about 23 ms latency, which is just too high for comfort. Hence, I was wondering about SPDIF and the Kemper's master preference. I know it's not something that can be changed, but it did pique my interest.

  • Well, the computer devoted to making real-time music should be optimized for the purpose: killing most of the services, no antivirus, no firewall, no internet, no background tasks, the minimum amount of drivers.
    I use a dual-boot option for this.
    Also, mandatory IMO are a motherboard optimization (BIOS), firewire or internal ASIO soundcard with 2 ms latency declared, excellent drivers and direct monitoring option.


    When this is not possible, Windows for example (I use a PC) allows to create different users with different environments (drivers, services etc): it's not the same, but it helps.


    :)

  • ... I migrated to Samplitude because I prefer the "sound" (entirely subjective, but I'd say it has a more open and neutral character) ...


    Don't get me wrong, I'm just joking but this is the second weirdest statement ever, right after "the earth is a flat disc". :thumbup:
    On a more serious side ... if you prefer the filters for some reason, ok. But the software flat in flat out can't make a difference in sound. ;)

  • Was reading a Sound on Sound article and came across this interesting line: "For instance, in the case of a typical ASIO buffer size of 256 samples in a 44.1kHz project, latency is 256/44100, or 5.8ms, normally rounded to 6ms. Similarly, a 256-sample buffer in a 96kHz project would provide 256/96000, or 2.6ms latency."


    You need to double that amount. That buffer number applies to in and output buffers.


    I'm curious though...are you monitoring the Kemper through your DAW when recording? Is there no mixer for your audio interface for direct routing? That way you can use whatever buffer you'd like with no latency.

  • Is there no mixer for your audio interface for direct routing? That way you can use whatever buffer you'd like with no latency.


    Sure there is, MixControl is pretty powerful once you get the idea of the custom mixes and the routing. Latency shouldn't be an issue at all.


    EDIT: Oops, I mixed up two threads, sorry. The OP seems to have a Fireface instead of the Focusrite Scarlett I assumed. But TotalMix should have similar functionality. Direct Monitoring for sure.

  • A double sample rate does not result in a lower latency.
    It results in putting double calculation power into the same musical output.
    You might end up increasing the latency to get a back a bit from the "sactified" calculation power.


    44.1 kHz provides the lowest load for your computer, thus the highest probability that a low latency setting will work for your project.

  • [


    A double sample rate does not result in a lower latency.
    It results in putting double calculation power into the same musical output.
    You might end up increasing the latency to get a back a bit from the "sactified" calculation power.


    44.1 kHz provides the lowest load for your computer, thus the highest probability that a low latency setting will work for your project.


    I'm no audio expert, but that's what the Sound on Sound article suggested, so I thought I'd post. Perhaps it's not exactly a 1:2 difference, but I'm sure there must be some correlation. With modern computers these days, where you have multiple cores and higher frequency, processing power is no longer as big a limitation as it used to be. For example, I'm able to play modern games at 1920x1080 at the highest graphics settings on my simple i5 with a Radeon 6870 GFX card. Not anywhere close to top of the shelf.


    Of course, I agree that sound quality does not improve with higher sampling rates.



    Don't get me wrong, I'm just joking but this is the second weirdest statement ever, right after "the earth is a flat disc". :thumbup:
    On a more serious side ... if you prefer the filters for some reason, ok. But the software flat in flat out can't make a difference in sound. ;)


    You'd be surprised at the number of people that say this about Samplitude. All boils down to algorithms, just like the Kemper vs Axe FX II in some ways. Cubase sounds darker, Samplitude a little more open, imho. You should try the free trial and see if you concur. Of course, as I mentioned, this is all subjective, so there can be no end of disagreement, no winners and no losers :D



    I'm curious though...are you monitoring the Kemper through your DAW when recording? Is there no mixer for your audio interface for direct routing? That way you can use whatever buffer you'd like with no latency.


    The more I read about it online, the more I'm convinced it's a software issue. There are other people talking about the same thing on the RME and Samplitude forums. Of course I monitored with my hardware, it's a really good soundcard. But my issue was more connected with lost audio buffers (LABs) than latency. I could only eliminate LABs by maxing out my buffer at 1024. But this introduced a lot of latency when trying to record drums via midi. TotalMix is very functional, but I think the problem lies more in Windows 8.1 and Samplitude than it does my hardware. Still thinking about upgrading my motherboard though. Might check if there are any loose connections when I get back home today, now that I think about it.



    Well, the computer devoted to making real-time music should be optimized for the purpose: killing most of the services, no antivirus, no firewall, no internet, no background tasks, the minimum amount of drivers. I use a dual-boot option for this. Also, mandatory IMO are a motherboard optimization (BIOS), firewire or internal ASIO soundcard with 2 ms latency declared, excellent drivers and direct monitoring option. When this is not possible, Windows for example (I use a PC) allows to create different users with different environments (drivers, services etc): it's not the same, but it helps.


    I shall try this out too. But I already run my PC with minimal apps at startup, etc. And as mentioned, my interface is still top of the line years after it was launched, its really killer. BIOS is updated, device drivers up to date. Windows itself is another story, some of the programming is absolutely retrograde, judging from articles I've read.

  • I'm no audio expert, but that's what the Sound on Sound article suggested, so I thought I'd post. Perhaps it's not exactly a 1:2 difference, but I'm sure there must be some correlation.


    Yes, you get lower latency at a certain sample buffer since each sample is shorter. I think CK means that if processing power is what dictates usable buffer size you won't gain anything since higher sampling rates requires more processing power...and you'd have to raise the buffer.


    You just divide the sample buffer with sampling rate:
    256/44100 = 5,8 ms
    256/96000 = 2,7 ms


    As to having to use a 1024 buffer on your system....something must be wrong. It should definitely be capable of doing better than that, unless you're doing humongous projects..


  • You'd be surprised at the number of people that say this about Samplitude. All boils down to algorithms, just like the Kemper vs Axe FX II in some ways. Cubase sounds darker, Samplitude a little more open, imho.


    Statements like this have been tested and disproved on many different audio forums. It's likely the default pan law is the culprit, unless you are using different plugins which isn't a fair comparison. In any case, it's a modern day 'flat earth' analogy...laughable. My audio teacher swore Pro Tools sounded worse than DP, likely a different Pan Law was influencing him as well...... :D

  • Statements like this have been tested and disproved on many different audio forums. It's likely the default pan law is the culprit, unless you are using different plugins which isn't a fair comparison. In any case, it's a modern day 'flat earth' analogy...laughable. My audio teacher swore Pro Tools sounded worse than DP, likely a different Pan Law was influencing him as well...... :D


    That's why I added the caveat, imho (in my humble opinion). You could say the same thing about the Kemper and the Axe FX II. Agree? Disagree? :D

  • The Axe and Kemper are WAAAAY different beasts. The closest A/B test you could do on them is to profile the Axe with the Kemper. But I wouldn't be surprised if there were subtle differences - profiling a digital amp model is VERY different than making a digital copy of something. And really that's all DAW's are doing - they are digitally mixing tracks. The algorithms should be equally (100% transparent). There is no impact on frequency response or other aspects of tone, until you add effect sends.


    If you are inclined, try a double-blind test. Put the exact same audio tracks in both DAWs and export the audio mixdowns .wav files. Label them track 1 and track 2, so if someone else saw them, they wouldn't know which file came from which DAW. Then have a friend/roomate/etc play each file in a random order (ex. 1,1,2,1,2,2,2,1,2) and ask you which DAW you think it came from. Make sure you do this enough times to make the correlation statistically relevant. I think 10-20 attemps is enough. Then look at the recorded results and score how many times you picked the right DAW. I'd be surprised if you score better than 60%.

  • The Axe and Kemper are WAAAAY different beasts. The closest A/B test you could do on them is to profile the Axe with the Kemper. But I wouldn't be surprised if there were subtle differences - profiling a digital amp model is VERY different than making a digital copy of something. And really that's all DAW's are doing - they are digitally mixing tracks. The algorithms should be equally (100% transparent). There is no impact on frequency response or other aspects of tone, until you add effect sends.


    If you are inclined, try a double-blind test. Put the exact same audio tracks in both DAWs and export the audio mixdowns .wav files. Label them track 1 and track 2, so if someone else saw them, they wouldn't know which file came from which DAW. Then have a friend/roomate/etc play each file in a random order (ex. 1,1,2,1,2,2,2,1,2) and ask you which DAW you think it came from. Make sure you do this enough times to make the correlation statistically relevant. I think 10-20 attemps is enough. Then look at the recorded results and score how many times you picked the right DAW. I'd be surprised if you score better than 60%.


    Picking which is which might DAW be difficult. "Can you hear any difference," is what I'd be looking for in this case.


    Of course, "better" sound is so subjective, YMMV, IMHO, etc. Holds true for so many pieces of gear, I don't think software is any different.


    As I mentioned when I first said, "Samplitude sounds more transparent", it is so subjective. Due to all the trouble I've been having, I fired up Cubase yesterday and did a little "one shot, one take" recording. And you know what? Sounded pretty damn good to me!


    Have got in touch with Magix Support with regard to my Samplitude problem. Hope there's some kind of solution, otherwise it's money down the drain for all practical purposes.


    What the Kemper has to do with all this? Nothing, really. I suppose linking latency to 44.1 khz master only SPDIF is a bit of a stretch of the imagination, hoohoo. I just wasted $499 :wacko:

  • I just remembered Samplitude has an additional audio engine mode for low-latency monitoring, I found this info with a quick google:


    Quote

    as you already pointed out, hybrid engine is especially for monitoring through the software, when you need low latency.
    in this scenario, you can lower the cpu consumption, by switching channels, that are only playing back audio to economy engine, where they are played with longer buffers.
    for mixing, the economy engine is stable and good (slider to the left in settings).
    one thing that is maybe interesting is, that in hybrid where the audioengine is always running, you hear the tails of reverbs and other effects that prolongue sound, when you hit stop. can give some good information, what is going on there.


    BTW I use a Fireface 800 as well and it's perfect for no latency routing, have a look at that for a solution. I can usually get down to 48-64 if I need to in Reaper, although 128 is my default and I just use TotalMix to monitor inputs with zero latency.

  • I just remembered Samplitude has an additional audio engine mode for low-latency monitoring, I found this info with a quick google:



    BTW I use a Fireface 800 as well and it's perfect for no latency routing, have a look at that for a solution. I can usually get down to 48-64 if I need to in Reaper, although 128 is my default and I just use TotalMix to monitor inputs with zero latency.


    The more I think about it, the more I'm sure there's some kind of hardware conflict in my computer, most likely my firewire card. I think I'll pick up a new one and see what happens.