Author
|
Latencies of DSP Solution VS. FX-Teleport. What the developers say.
|
subconsciousmind
SCM
Started Topics :
37
Posts :
1033
Posted : Feb 28, 2007 19:01
|
Some may be interested
I wrote the following mail to TC-Electronic, Focusrite, Waves and Universal Audio.
Concerning the latencies of their DSP solutions compared to the latency of today audio interfaces and a special solution called FX teleport. (I find it a bit weak)
Of course the message was little different in tech spec. according to the company it went to.
---------------------------------------------
Dear Sirs
Your DSP solution has a fixed latency of 1024, respectivly 2048 samples for the roundtrip of the audio signal over your DSP.
This is exactly the same as it is with your competitive products.
But there is a software called "FX Teleport" (see http://www.fx-max.com/fxt/product.html#latency ) which uses a second windows computer over LAN to run plugins on it and it manages to send audio over LAN to the second computer and back into the sequenzer with a latency of 256 samples.
Experiencing this raises the question, why you product isn't able to have such a latency over Firewire, LAN, PCI or even PCIe?
Furthermore there are Firewire or PCI audio- interfaces from apogee or RME, which are able to send huge amounts of audio channels over an external analog or digital soundprocessor and back with latencies of 256 to 512 samples.
This again lets me ask the question: Why does your DSP solution have such a high latency? And is the quality of the offered Plugins today the only reason to buy a DSP Solution instead of a second computer and FX teleport?
This question has been raised in several forums and your answer is highly anticipated.
Thank you for your time and best wishes
THE ANSWERS:
---------TC - ELECTRONIC-----------------------
Thank you for your interest in our products.
The latency of PowerCore is not fixed, but dependend on the audio buffer size.
If the audio buffer size is set to 128 samples, the PowerCore buffer size can get as low as 128 samples.
We're constantly considering alternative ways to do processing, including streaming to other computers, but I can't say anything about specific future plans for TC.
Thanks for the input.
Best regards
Thomas Valter
Product Manager
TC Electronic
------------------------------------------------
---------Focusrite------------------------------
Hello Raphael,
Here is the info from our development team:
For the current release of the Liquid Mix, we chose a fixed latency of 2056 samples to support DAW buffer sizes up to 1024. This decision minimises the overhead on the CPU and by guaranteeing a fixed delay makes delay compensation and sample accuracy between multiple channels easy to guarantee, as well as providing high data integrity for the avoidance of any audio glitches.
Latencies approaching 256 samples at 44.1kHz are now becoming possible with recent fast computers, although there is inevitably an increased overhead on the native CPU and an increased risk of other processes on the computer interfering with the audio. However we expect such latencies to be practical in the near future on well maintained host computers, and our policy of constant improvement means we will make these available as soon as we are confident that performance meets our stringent requirements for reliability and data integrity.
[We are working on 1.6 version of liquid mix at the moment which includes lower buffer size operation]
Solutions using LANs based on, for example, ethernet technology are intrinsically more susceptible to data corruption when used with short latencies because, unlike FireWire, ethernet was not designed originally with the concept of real time service, but for packet based communications of bulk data where arrival time cannot be guaranteed. Please see the note at the end about the example you cite.
Liquid Mix provides unique emulations of classic EQ and compression that are not available on any other processing platform. The hardware has been optimised for the task and is extremely cost effective. Choosing a second general purpose computer to run these emulations would have been a more expensive and less satisfactory solution.
The fact is that the quality of the emulations is an overriding factor and is the reason for choosing Liquid Mix over the solution you suggest.
Notes on reference cited http://www.fx-max.com/fxt/product.html#latency
The system cited makes it clear that you cannot guarantee latency with the solution proposed. For example it states "In case of network overload the red indicator will show up, meaning that some audio packets have been lost". It also makes an unlikely claim that "Our tests have shown a latency of 128 to 256 samples (or even less) with the audio card buffer set to 128 samples". However you have to ask how latencies smaller than the audio buffer sizes are achievable, as this packet of data has to filled in the plugin, transferred to the audio output, buffered to the D/A converter and fed to audio amplifiers. The actual example quoted is of playing synthesisers hosted on a remote machine. This is a situation where data integrity can easily be ignored as the play data to the remote processor is not audio but are small data packets which can be transferred quickly, and the return audio from the sequencer is fairly tolerant of audio glitches as it has no audio reference to compare it with. While no doubt an excellent tool, we would suggest that in order to assess latency and audio integrity, an extended period of bidirectional audio processing is tested to estimate the true workable latency in real situations.
Let me know if you need more info,
Oliver
This message and any attachments are confidential to the user of the e-mail address to which it was addressed. The sender does not accept liability for any errors or omissions in the context of this message which arise as a result of Internet transmission. Any opinions contained in this message are those of the author and are not given or endorsed by Focusrite or office through which this message is sent unless otherwise clearly indicated in this message and the authority of the author to so bind the Focusrite entity referred to is duly verified.
-------------------------------------------------------
------------Waves--------------------------------------
Thank you for your mail.
We are aware of NetShell’s latency. NetShell was never meant for live usage and as a studio based system for mixing it is designed to work with a latency-compensating DAW – as such, low latency wasn’t considered an issue. NetShell’s latency is even lower then some of Waves plug-ins, DeBreath for example. We indeed agree that a NetShell-type system that is aimed for live usage would be required to run in low latency. It’s an interesting direction.
As a solution NetShell prioritizes resource usage efficiency (CPU, LAN, memory, etc.), wide support base (VST, AU, RTAS, ...), scalability, and other aspects higher then low latency, although latency is an aspect we’re working to optimize as well. Be aware that some of the supported hosts put boundaries to the lowest latency you can set, boundaries NetShell cannot cross without violation of the host’s API.
Please let me know if you will need any further information or assistance. Please include a copy of our on going correspondence in your mail.
Thank you for your cooperation,
Best regards,
Barry Cohen
Inside Sales
Waves Audio Ltd.
later another mail:
I wanted to add to my previous mail.
Waves main concern when developing our Audio Processing Accelerators was a focus on audio integrity and quality. We found for our initial release that lower latency setting, like with other 3rd party Ethernet solutions, would drop and degradate audio. This was simply unacceptable to Waves standards and the decision was made to not include lower latency setting to assure the highest quality process. This does not mean however, that we do not have plans to release lower latency support in the future for our APA line.
--------------------------------------------------------------
----------------------Universal Audio-------------------------
they sent a message, telling me that only the developers know, so they will forward the message, and that I'm not allowed to quote their message...
I never received an answer
-----------------------------------------------------------
  Most of my music for you to download at:
http://www.subconsciousmind.ch |
|
|
Dharma Lab
Started Topics :
8
Posts :
342
Posted : Feb 28, 2007 20:54
|
Interesting indeed, thanks for posting your inquiries!
Anyone using FX Teleport over firewire? Was considering toying with it, as I run out of CPU power regularly, but also have an extra PC sitting around doing nothing....
  Keep The Faith,
Christian K. |
|
|
sideFXed
IsraTrance Junior Member
Started Topics :
22
Posts :
430
Posted : Mar 1, 2007 03:14
|
I'm using fx teleport with gigabit lan. works very well and the latency is okay. Never tried firewire though.
  soundcloud.com/epsylohm |
|
|
subconsciousmind
SCM
Started Topics :
37
Posts :
1033
Posted : Mar 1, 2007 08:31
|
I'm using Focusrite Liquidmix (Firewire), It's a nice tool. Quality of EQ and Compressors are nice, but latency is as mentioned above (the low latency mode doesn't exist so far).
Since I'm not the "first compose than mix" type but play new stuff all the time the latency is a little annoying.
I also use 2 RME Fireface 800, it's firewire and I can go down to 3ms If I have to as long as I'm under 50% CPU
I think I will try out FX teleport too. But what I still love about DSP solutions is the quality of the plugins.
  Most of my music for you to download at:
http://www.subconsciousmind.ch |
|
|
faxinadu
Faxi Nadu / Elmooht
Started Topics :
282
Posts :
3394
Posted : Mar 1, 2007 11:58
|
|
subconsciousmind
SCM
Started Topics :
37
Posts :
1033
Posted : Mar 1, 2007 13:17
|
Latency compensation of course works. But it's not the point in my workflow.
As long as you are only mixing it's fine, but from the moment you press a key on your keyboard or hit a drumpad, the computer just has to react as soon as possible.
And since todays, and I guess tomorows comuters as well, are not able of precognition, you will always hear the latency from the moment you pressed the key, till the sound comes out of your speakers. Nobody can compensate that.
If I have a VSTInstrument, which has a DSPbased effect in the insert, i have to wait 2048samples till the dsp is done, and the another 512samples (or what ever is set) till the sound card generates the signal.
Even worse it is with my external synths.
I press the keyboard, then I have to wait for the soundcard latency till the signal is in the computer, then it adds the plugin latency (if any) and then again the soundcard latency till the sound is back in the external world...
  Most of my music for you to download at:
http://www.subconsciousmind.ch |
|
|
pilgrim
IsraTrance Junior Member
Started Topics :
19
Posts :
218
Posted : Mar 1, 2007 15:59
|
Quote:
|
On 2007-03-01 13:17, subconsciousmind wrote:
Latency compensation of course works. But it's not the point in my workflow.
And since todays, and I guess tomorows comuters as well, are not able of precognition, you will always hear the latency from the moment you pressed the key, till the sound comes out of your speakers. Nobody can compensate that.
If I have a VSTInstrument, which has a DSPbased effect in the insert, i have to wait 2048samples till the dsp is done, and the another 512samples (or what ever is set) till the sound card generates the signal.
Even worse it is with my external synths.
I press the keyboard, then I have to wait for the soundcard latency till the signal is in the computer, then it adds the plugin latency (if any) and then again the soundcard latency till the sound is back in the external world...
---
|
|
---
You could use the direct monitoring from yur soundcard and therefor bypass the daw and avoid quite a bit of the latency....
Regards, pilgrim
|
|
|
subconsciousmind
SCM
Started Topics :
37
Posts :
1033
Posted : Mar 1, 2007 18:28
|
direct monitoring works for some cases, but most of all I want to hear the efx while playing.
I use direct monitoring in very view occassions with the external stuff. with the internal it just isn't possible.
  Most of my music for you to download at:
http://www.subconsciousmind.ch |
|
|
|