Crackling In Renoise When Cpu Is Above 50%

Hi everybody!

I’ve been using Renoise for a couple of years now but am new to the forums (pleased to meet you all :)).I am currently running Renoise on a mac book pro connected to a Mackie Onyx 1220i firewire interface. When the CPU reaches above 50% (sometimes less) in Renoise I am experiencing annoying crackles and stalls in playback. Surely my comp should be able to handle this amount of CPU use?

I have browsed some other posts to see if there was any info and it seems that a low latency setting could be the problem here (I have mine set to 5ms). I was wondering, if this is the problem and I need to increase the latency how this would affect the performance of Renoise?

Is there any other reason you guys can think of as to why this is happening?


Does it improve much if you double the latency?

From what I’ve read Apple have not used a truly compliant firewire chipset in the MBP for a few years now (2-3) which may lessen performance with time-critical firewire devices, such as soundcards. This may be a red herring though, have seen people argue that the speed of processors now well enough offsets this disadvantage but I personally think that is a poor argument. Although on paper (or as far as the protocol is concerned) firewire is better than USB it often doesn’t turn out that way, assuming a single device is attached to the bus (you often have other bits and bobs on USB degrading its functionality.)

Drivers and device firmware may also be worth checking are latest version.

I don’t know if Macs offer any finetuning in the way of prioritising audio threads and if this could help. I would guess this is the kind of thing Apple have locked away to try and make it as idiot proof as possible though…

Rootmitten, one thing that I’ve noticed, it sometimes depends on the VST Instruments and FX you use. I’ve had some songs up to 80% CPU load (Renoise’s own CPU meter) without crackling or audio issues with a buffer size of ~256 samples @48khz, 24bit which is about 5ms.

But what I have noticed is, even at about 40% load, some songs will crackle and I have to increase my latency.

Now the kicker seems to be, some FX plugins I’ve tested add their own latency and I think that causes the issue.

One thing you can start doing is opening up a new track, then load some higher end FX/Instrument plugs, make 10 instances of your fave EQ/compressor and start seeing which plugins add extra internal latency.

Hope that makes sense.

I’ve now had to start being conservative with some FX I use, even on my brand new Core i7 2600K.