Topic: Which barebone pc

Hello,

I am thinking to mount a barebone pc just for Pianoteq.

So,

What is the minimum CPU required to run Pianoteq without dropouts at 128 samples in 48Khz, for an indicative latency of 2,9msec, and at least 96 of polyphony?

Any help is welcome

SK

Re: Which barebone pc

You should be fine with a 2 GHz dualcore, I think...

Hard work and guts!

Re: Which barebone pc

You talk about Audio parameters, but nowhere do I see what audio device you are going to use.

The audio device and its drivers have a big impact on all the audio parameters, while at the same time even a modest modern PC or laptop has enough performance to play Pianoteq.

Re: Which barebone pc

geert wrote:

You talk about Audio parameters, but nowhere do I see what audio device you are going to use.

The audio device and its drivers have a big impact on all the audio parameters, while at the same time even a modest modern PC or laptop has enough performance to play Pianoteq.

An external soundcard, Focusrite Scarlett 6i6

Last edited by stamkorg (04-07-2015 08:37)

Re: Which barebone pc

EvilDragon wrote:

You should be fine with a 2 GHz dualcore, I think...

Thank you,

I have now a 2-core 2,53 Ghz on a laptop. It is a 5 years Pentium I5-460M. It works ok but then fan makes a lot of noise.

My question now is whether a new low TDP, for example an i5-4570T (TDP 35W, double 2,9Ghz) could do the job or not. Probably yes... with the advantage to keep cool with only a passive cooling system, so no noise a all.

But generally speaking, when the CPU frequencies are the same, are the new generation more powerful than the old? And also, a 2-core 3Ghz from AMD is it the same than a 2-core 3Ghz from Pentium?

Last edited by stamkorg (04-07-2015 08:59)

Re: Which barebone pc

I can't answer for today's processor, but I do remember that the Pentium IV has a longer pipeline than the Pentium III, which makes it speed lower than the P-III at the same frequency. (But it could work at a higher frequency... This was the purpose of the longer pipeline)

Last edited by floyer (04-07-2015 09:33)

Re: Which barebone pc

i5 would be more than enough, ANY i5! And yes, newer generations do have performance improvements over older generations, that's a given. And yes, low TDP means less heat generated means fans have to work less. Go for it.

Last edited by EvilDragon (04-07-2015 09:42)
Hard work and guts!

Re: Which barebone pc

The latest Intel generation is called Broadwell.  A 1.5ghz Broadwell would be about the speed of a 2.5ghz from 5 years ago (Sandy Bridge or Ivy Bridge).

In a large PC case, you will have to pick a 15W-17W CPU to do fanless.  Fanless will be very hard for a 35W CPU.

In a small form factor, fanless would require something from the even lower-powered families.  For example, the following is a 10W 2.4ghz quadcore Baytrail Atom designed for MINI-ITX cases and does not normally need a fan:

  http://www.newegg.com/Product/Product.a...6813135392

There's been successful reports of Pianoteq running on 2ghz Baytrails before (and unsuccessful attempts on 1.4ghz Baytrails) so the above will be fast enough.

Looking up the Pianoteq benchmarks I ran in off-line mode on my Baytrail server, a quad-core 2.4ghz Baytrail is roughly the speed of a dual-core 1.5ghz Broadwell.  The difference is you can get a full system running at 5W-10W on a Baytrail versus 15W-20W on a Broadwell.  Intel sells 6W Broadwells but they are capped at 600MHz so I'd pick a 6W 1.8GHz Baytrail over that anyday.

Last edited by Mossy (04-07-2015 09:52)

Re: Which barebone pc

That's quite informative, Mossy.

I wonder what's the polyphony and minimum latency possible on that Baytrail.

Hard work and guts!

Re: Which barebone pc

Mossy wrote:

No way you can do fanless with a 35W CPU.

I will try that:

http://www.akasa.com.tw/search.php?seed=A-ITX10-A1B

It seems to be designed with an integrated fanless system for processors up to 35W of TDP.
On the specifications page they give the compatible CPU. It should be ok with a i5-4570T

Last edited by stamkorg (04-07-2015 09:54)

Re: Which barebone pc

I use a MOTU microbook 2, and cannot detect any difference between my I3 laptop ( 8 Gig RAM) and my I7 PC (16 Gig RAM) concerning latency and audio stability.
I most of the time play piano with the Toshiba I3 laptop, which consumes much less power of course.
The I7 is for playing the organ (Hauptwerk).

Re: Which barebone pc

I use Intel Pentium 2020M with passmark 2303, Pianoteq with optimistic polyphony setting, 256 samples, 44.1 kHz and my CPU load always < 50%.

I think every CPU with passmark > 2000 is OK for Pianoteq.

P. S. I think it's impossible to see any difference between 128 and 256 (and even 512) samples. You also shouldn't forget that even acoustic pianos have latency about 10-30 ms because of mechanics.

P. S. It's impossible to hear difference between 48k and 44.1k because of your ear limitation and Nyquist theorem. The only reason to use 48k is eliminating resampling if some device or software that process Pianoteq's output works in 48k (or multiple of).

Combine velocity curves: http://output.jsbin.com/cukeme/9

Re: Which barebone pc

Ross wrote:

I use Intel Pentium 2020M with passmark 2303, Pianoteq with optimistic polyphony setting, 256 samples, 44.1 kHz and my CPU load always < 50%.

I think every CPU with passmark > 2000 is OK for Pianoteq.

P. S. I think it's impossible to see any difference between 128 and 256 (and even 512) samples. You also shouldn't forget that even acoustic pianos have latency about 10-30 ms because of mechanics.

P. S. It's impossible to hear difference between 48k and 44.1k because of your ear limitation and Nyquist theorem. The only reason to use 48k is eliminating resampling if some device or software that process Pianoteq's output works in 48k (or multiple of).


Hello,
I agree with the fact that we can't hear a difference between 48k and 44,1k
I use to play at 48k to avoid this resampling.

Now for the samples, for me it makes a huge difference in the connection with the instrument. Since I am used to play at 128 samples, it is impossible for me to return to 256...

Re: Which barebone pc

Play at 48k ONLY IF your audio interface natively works at 48k (best found out by asking the manufacturer directly)! Otherwise it's resampling for no good cause.

Ross wrote:

P. S. I think it's impossible to see any difference between 128 and 256 (and even 512) samples. You also shouldn't forget that even acoustic pianos have latency about 10-30 ms because of mechanics.

It is definitely a noticeable difference the further you lower buffer size, the lesser the round-trip latency. Buffer size is just one part of the whole latency figure. For piano this might not be a terribly huge deal, so 128 would work fine for pretty much anyone (512? no way in hell!). For a more direct instrument, like a guitar, lowest possible latency is necessary (64 or even 32).

Last edited by EvilDragon (05-07-2015 10:10)
Hard work and guts!

Re: Which barebone pc

Pretty much any regular desktop or laptop will be fast enough to handle max/near max settings on Pianoteq.  This story changes though if you want a completely silent system with no fans.

I had the cpu fan my a laptop (35W i5) die a while back.  Until I got it fixed, I had no choice but to underclock the CPU to run at a maximum of 1.2ghz.  In addition, I had to take the bottom lid off and expose the electronics the open air.  Otherwise, the CPU would hit 100C in a blink of an eye, shut down automatically and take 15 minutes to cool off before it would power back on.

Maybe those special cases where the entire case is one giant heatsink can cool down a 35W CPU enough but you have to spend the money just to experiment with the system.  With a 7.5W/10W Baytrail (Pentium J2900) or a 15W Haswell (Celeron 2955U), your odds of being able to passively cool the system will greatly increase.  However, you probably do need to drop the sample rates down a bit for these CPUs.  From my own experimentation with my forced-underclocked system, 22khz internal sampling + 44khz output device sampling will let you do about 200 polyphony (held down sustain pedal and pounded random keys nonstop).  44/44 though will drop notes unless you limit polyphony to about 100.

Re: Which barebone pc

You can go silent and fanless with some CPUs up to about 95W, you just need the right case and CPU cooler. I am currently looking at going completely fanless and silent with an Intel i7 4790K which is rated at 88 Watts.

If you want an idea about what is possible for passive cooling see my favorite supplier of parts for making a silent PC: http://www.quietpc.com.