[LAU] another cpu question

[Ede Wolf]

Thanks for reply.


it is kind of live use. But not on stage, but in my humble homestudio. 
So I do not have to be mobile, but I am not arranging, I am just playing 
live - that is, enjoy turning a lot of knobs without any real clue. And 
if it sounds crap for a given day, I at least do enjoy all the blinking 
lights.

The card is an old RME Hammerfall (not even DSP), and I'll be using X 
with a standard distro. Gentoo or Arch - or maybe KX, if they really 
should drop ubuntu as a base, as I've read somewhere. Depending on the 
software I'll be using in the end.

So we are talking about a simple desktop PC in a tower case with an 21" 
CRT Monitor.

About multitrack: Being able to run 32 effects (8 Tracks x 4) would be 
great, 16 tracks perfect, but my budget is not infinite and I doubt I'll 
really use 16 Tracks at once. And most likely not really reverb on all 
tracks, that is just the worst case to find out a proper CPU.

However, there will be differnt rooms on different tracks. There is 
still an external master reverb inserted into main mix. If so desired.

Maybe I'll try to control some of the effects via Midi - I do own an old 
Doepfer Drehbank controller, but not sure, wether I'll have the patience 
to program it before winter. Maybe handy for the EQ. But it's also 
occupied for the microwave II.
However, EQing with a mouse is a PITA and something I will have to solve 
sooner or later. Way worse then setting up reverb or delay. imho.

I do not plan to use effects via aux sends, just stack one on top of the 
others in a serial manner - as if I would do, if I had 8 hardware effect 
devices plugged into my mixer.

There won't be any mixing (as in mastering) - at least not on this box, 
I am oldfashioned and need real faders. I do have another box for 
recording - mostly straight to /dev/null, that is unfortunately.

This box will just be plugged into the inserts of my mixer - therefore 
the ideal of 16tracks - which I suppose will be cheaper and better to 
use than buying a couple of multieffects. I do not have any more ADDA 
convertes anyway. And for my lousy ears, the quality of named plugins is 
more than adequate.

So it's basically -> jack-in->effect1-effect2-effect3-effect4->jack-out 
with 16 permanent physical connections bewteen soundcard and mixer. 
Though not all of them will be used at once.

I do have the soundcard (which I finally do inted to use properly after 
all those years) and the ADDA converters, the screen, SSD and the case. 
All I need is a mainboard, CPU+cooling and some RAM. And maybe an el 
cheapo graphics card, if going the AMD route.

I doubt I'll get usable multitrack hardware for that money.  Sure, I am 
screwd if one of those parts breaks, it's all yesterdays jam and hard to 
get besides waiting for ebay.

The price limit is a bit difficult as prices are varying between 
countries. As I've said, an upper class intel i5 or AMD is about what I 
am thinking of, until general consesus is, that there is no way to 
accomplish this with standard, upper class (as opposed to high end) PCs.
Then maybe I'll wait a little more and save some money.
But, as you mentioned, I do remeber running softwareeffects, even not 
really in parallel, way back on an 2GHz AMD 3200 in decent quality even 
on WIndows, so a modern multicore, I would suspect, should be able to 
run a couple of them. Just which would be the best bet.

For hardware devices: Behringer is out of discussion. As is Alesis. I do 
have a couple of midiverbs and found the quality of calf to be way 
better. If maybe not for the algorithms, then at least for the noise level.
Indeed, I am planning to sell those. For peace with my drumheads and of 
course for better useability.

So again - are plugins really FPU heavy? Or would it be more important 
to have feature X, like AVX or SSE27 or so? Unfortunately I am not 
really into this recent hardware stuff and all the latest buzzwords.

And I usually do not trust benchmarks, but that's all I have and the FX 
series did quite well in some so called media benchmarks, like 
rendering, however, I am not sure whether this can be tranferred to 
running multiple audio effects without problems. AS maybe rendering is 
just two fast threads instead of 16 medium ones. Dunno.

The price advantage for the AMD would probably be eaten up by the more 
expensive colling - I prefer it rather quiet - and the higher energy 
bill. But if it would be the more adequate CPU for this very workload, I 
would go that route.  i7 are all HT, so that would leave the i5 as only 
other option.



Am 13.09.2014 18:14, schrieb Len Ovens:
> On Sat, 13 Sep 2014, Ede Wolf wrote:
>
>> I may be putting together a box dedicated just to act as a multitrack
>> effects unit - without planning any recording. The effects stack will
>> for most
>
> My guess is that this will be used live then? So you must have an audio
> interface in mind and a channel count. I am guessing that this will end
> up rackmount with a MB that has PCI(e) slots? Will it have a gui screen?
> or be run via MIDI/OSC/custom control surface? (I would recomend
> something sort of standard as it may be nice to have a MIDI control
> surface on a desk particularly for EQ use... though a touch notepad
> Interface might work too)
>
>> channels most likely look like this: reverb, delay, EQ and maybe one
>> of flanger, chorus or rather seldomly compression. Anyway, just the
>> classics, planning so far to only to install the calf and invada lv2
>> packages. Though I am open for recommendations here, too. And of
>> course I am looking for a suitable effects host/rack.
>
> Because you have (I would guess) a set number of channels you have the
> option of looking at either a multitrack mixer such as non-mixer or a
> set of stereo racks. I would put all the possible effects in line but
> have the ones not used bypassed... at least I would try that. This is so
> that it is easy to set up a midi controller. I suppose I should also ask
> if you are going to do any of your own coding to glue this together. You
> will probably at least need some shell scripts to set things up unless
> you will have some sort of UI that will allow manually setting this up
> every time.
>
> Another question... Will X run? Or will you be running all CLI?
>
>> However, I do suppose, the reverb will be the most cpu consuming item
>> and I am wondering, what feature an a cpu should I be primarily
>> looking for? I guess, for effects, especially reverb, the floating
>> point performance will be paramount?
>
> Without a track count, it is hard to know. multitrack could be 4 or 24
> tracks. Even then, it would be hard to tell as I have found changing
> parameters within a plugin can change cpu use of that plugin. Of course
> knowing what latency your IF is capable of and the latency you intend to
> use is important too. It would be pretty easy to say that a dual xeon
> board would handle it, but then one of the new 8 core atom boards may
> work just as well... note: I don't know how far a single audio chain can
> be split over cores.
>
> WRT reverb: Do you really want each track to have it's own reverb?
> Having one reverb (or two) service a number of tracks through sends is
> not only done to conserve CPU cycles. It also lets the sounds be in the
> same virual acoustic space. However, setting up the sasme reverb 5 times
> does allow each track to be dealt with separately.
>
> Another question: will you be mixing the outputs? (sometimes, never)
>
>> As HT generally has a bad reputation for audio, currently, the AMD
>> FX-8350 is on top of my list, as the floating point preformance is
>> said to be rather good and lots of cores should be ideal for running
>> lots of effects in parallel - though unfortunately not every core does
>> have its on FPU. As it is not going to run 24/7, the insane energy
>> consumption is somewhat acceptable.
>>
>> But, beeing no coder, I may be completely off track with my
>> conceptions here, so I am asking for some more insight or alternative
>> recommendations, maybe even with a short reasoning
>
> What parts do you already have? What is your budget? What is your reason
> for wanting to do this in a computer rather than just buying something
> that has these things. By the time you buy the interface ($500 for 8
> i/o), case, MB, CPU, memory, PS, HD, midi controller and PCIe card for
> the audio IF... you are getting close to the $2000 mark already. (this
> is noting that you said this is a one use box) You can buy a digital
> mixer with 16 channels already. You have said that there is not some
> effect that you want in particular, but generic effects.
>
> Look at:
> http://www.allen-heath.com/ahproducts/qu-16/ ~$2100
> http://www.behringer.com/EN/Products/X32-RACK.aspx ~$1200 (Sweetwater)
>
> I am sure there are others too.
>
> This is not to say your project is not valid. I am just trying to make
> sure you have some perspective. BTW, the units I pointed out do not use
> one fast CPU, but a number of ARM and DSP units. If you already have
> most of the parts on hand... particularly if you have a spare computer
> even with only two inputs. I would try it out with that for two tracks
> so you have an idea of what sw is around. You can try more tracks than
> two by just setting them up, as jack does not care if inputs are
> physical or not. Playing back *.wav files does not take much cpu.
>
> I was able to do quite a lot with just an old P4 even at low latency,
> The new i5 already makes audio use much less cpu. (even with jack set
> 16/2) All of todays CPUs are beyond yesterdays super chips.
>
> --
> Len Ovens
> www.ovenwerks.net
>