VB-99 - Latency of the VB99

Started by fokof, June 19, 2009, 10:18:01 AM

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fokof

A little "heads up" for users , sory if this has been discused....

After a couple of months of use , I think I finally found "My way" of using the VB-99 (yeah , right....)

The A is used as my mag pickup processor , mainly flat , no COSM amp , with light Chorus and reverb programmed at the FC300
The B is used for all the other sounds/FX I need.
I always use the same A , and the B always changes.

I had a lot of volume problems from patch to patch when both A/B were 50-50, so I thought it's was phase problem.
In fact it's a latency problem.
I recorded A as my direct signal (no FX) and B as a COSM bass & amp , and I have a 6,19ms delay between both.
Just do the test , center pan A and B , listen , apply 6ms to the Direct , ..........yeah.... :'(
On the pic the top is the A direct , the B is the COSM.
The first attack is without delay , the second attack is with a 6ms applied to the direct signal(A)

The "boxiness" of a phase problem sound is now gone.
Just wanted to share the tip.

EDIT: curious to know what it is on the VG99 ?

Brent Flash

#1
The VG-99 is the same I would guess, but I don't use the Mag pickups so I am not concerned. I would bet if someone would look at it the way you did, they would find the same amount of latency because of processing differences.

Even not using the Mag pickups I find that the delay in the Mixer section can act like another tone control because of the phase relation but is not easy to predict what it will do?  ::)

I would guess with bass there is more of a problem than with the higher guitar frequencies. Interesting post! ;D

SteveFromBerlin

Man, this is a really interesting post you did there!

It probably will change the way I use it a little bit. Most of my Patches are similar to yours... I often use the A for my magnetic pickups. But I often have the normal FX linked to the 1 & 2 button, which sometimes turn in two or more FX (e.g. chorus and reverb simultaniusly or M-Tron III and Octaver).




fokof

Found out something else concerning latency , there is a slight latency (haven't checked how much) between the "direct" signal and a "normal Pickup" , even without any FX. It's worst when an FX is on (normal)

Probably due to the fact that the signal passes through processing even if nothing is applied as the "direct" is probably as stated ; direct.

Just a little "heads up" ;)

aliensporebomb

Question:  how are you adding 6 ms delay to A so it doesn't sound until "B" gets the show on the road?

Do you have some audio examples of this delay happening? 

Are you running regular 4-string bass or 5 or 6 string?

And are the patches with the latency showing synthesizer type patches? 

I'm wondering why the delay if it's just modeling an effect or amplifier tone.

I wonder if it's similar to the delay with the GR300 emulation on the VG99, Premiere Guitar said that the delay on the GR was something on the
order of 12 milliseconds but on the real GR300 it was 2-3 milliseconds.

At least that's my recollection for the article contrasting and comparing a VG99 emulation of a GR300 and a real GR300.
My music projects online at http://www.aliensporebomb.com/

GK Devices:  Roland VG-99, Boss GP-10, Boss SY-1000.

fokof

#5
Quote from: aliensporebomb on September 08, 2009, 10:13:17 AM
Question:  how are you adding 6 ms delay to A so it doesn't sound until "B" gets the show on the road?
In the mixer section , there is ch delay , it's the 5th button on the first page.
It adds delay compensation for latency. A problem is that it is 1ms increments. that is way too big, but it's better than nothing.

Quote from: aliensporebomb on September 08, 2009, 10:13:17 AMDo you have some audio examples of this delay happening? 
Put your A to normal PU , nO FX no COSM amp
Put your B to a COSM bass (or gtr) , add FX , add COSM amp
You'll clearly hear a phasing problem.
It's something mor apparent in the low frequencies , with bass , it can be real problematic , not so with guitar. Only on lower register.
Quote from: aliensporebomb on September 08, 2009, 10:13:17 AMAre you running regular 4-string bass or 5 or 6 string?
Both my basses are 5 strings with a low B

Quote from: aliensporebomb on September 08, 2009, 10:13:17 AMAnd are the patches with the latency showing synthesizer type patches? 
Nope. regular bass sound.
As I told you , you can try it yourself.
I guess that this phenomenon is less likely to be problematic with guitar.
Quote from: aliensporebomb on September 08, 2009, 10:13:17 AMI'm wondering why the delay if it's just modeling an effect or amplifier tone.
It's the processing of the CPU that causes it.
The sound is A/D'ed then processed , then D\A'ed.
The more FX and COSM you put , the more latency you have.
It's the same thing as with a computer.

Quote from: aliensporebomb on September 08, 2009, 10:13:17 AMI wonder if it's similar to the delay with the GR300 emulation on the VG99, Premiere Guitar said that the delay on the GR was something on the
order of 12 milliseconds but on the real GR300 it was 2-3 milliseconds.
At least that's my recollection for the article contrasting and comparing a VG99 emulation of a GR300 and a real GR300.

Can't answer that, I'M pretty new to Roland's stuff
( but I have a very big experience with CPU ;) )

A2theT

Yes I've noticed the phasing issue too.  I send my output to some monitors and adjust the a/b delay all the time when making patches in order to accomodate and make it sound the best I guess.
HEAVY on the METAL
Axe-Fx II, Roland VG-99 + FC-300, Roland GR-55, Digitech Jamman Stereo, Ibanez/ESP/Jackson Guitars

fokof

#7
FYI

I tried a couple of patches lately where I would blend the mag and COSM in the COSM intrument window.
I usually use A intrument direct and B as COSM and add a delay on A only.

The phasing issue using it that way is VERY noticable and annoying , not very usable with bass guitar , since we cannot put a delay on the mag input only this way.

fokof

Quote from: fokof on September 07, 2009, 07:45:30 PM
Found out something else concerning latency , there is a slight latency (haven't checked how much) between the "direct" signal and a "normal Pickup" , even without any FX. It's worst when an FX is on (normal)

It's 100 samples @ 44,1Khz , so around 2,27ms between the "Bass Direct" and the "Normal PU" level.

( So much time to waist  ;D )

388314

Quote from: fokof on June 19, 2009, 10:18:01 AM
EDIT: curious to know what it is on the VG99 ?

Well I did a test similar to yours, although I luckily do not have phasing problems on the VG99.
I've found out that there is virtually no latency between COSM guitar and Synth sounds (<10 samples @ 48kHz) and that there is a slight delay between magnetic pickups and COSM guitar: COSM guitar -> COSM amp is less than 1ms late compared to mag pickups -> COSM amp (same model).
However, the whole processing takes between 2 and 3 ms, just like on your VB99: comparing COSM guitar -> COSM amp and direct out (which is before A/D conversion) gives me 130 to 150 samples @ 48kHz.

fokof

Interesting ........
Thanx for the results



Nice to see you use DP too  ;)

388314

Quote from: fokof on August 01, 2010, 02:17:04 PM
Nice to see you use DP too  ;)

Yeah! They tried to push me towards Logic but I find it too "Apple style"  ;D

fokof

Did another test :
If I want to use a real pedal , using the USB and I/O of my soundcard (828mkIII)

so the D/A > pedal > A/D then back in the VB99 adds 10ms of latency.
Not too bad.


It's less than that using a plugin but for those of you who wants to use an analog processor , it's gonna be around this number.
What's nice is the flexibility to take the USB signal anywhere in the chain.

gumtown

Does the difference in latency between mag & modelled sounds change as you move up the scale in pitch. I would suspect that part of the time would be for pitch tracking or something, so as the frequecy increases,the peak to peak detection time is shorter (just like pitch to midi systems).
Would a breakout of the mag signal before the VG-99 with a phase shifter stompbox pedal help?
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

388314

Quote from: fokof on October 10, 2010, 02:51:59 PM
What's nice is the flexibility to take the USB signal anywhere in the chain.

If only they had done the same with an analog loop... I would love to try throwing a valve preamp in the chain!

Elantric

#15
QuoteI would love to try throwing a valve preamp in the chain!

Read the GR-55 Missing Link thread for a  new unit shipping soon that works with VG-99 and VB-99 that allows you to add many other FX in your "Normal PU" signal chain, in front of the VG/VB/GR processors.

https://www.vguitarforums.com/smf/index.php?topic=2940.0

fokof

Quote from: shamael on January 27, 2011, 07:29:16 AM
If only they had done the same with an analog loop... I would love to try throwing a valve preamp in the chain!

I use a RMC Fanout box for this , I throw in a TD100 , it adds a little "tubey" tone to my mag signal before getting to the VB.

fokof

Quote from: gumtown on January 27, 2011, 02:02:05 AM
Does the difference in latency between mag & modelled sounds change as you move up the scale in pitch. I would suspect that part of the time would be for pitch tracking or something, so as the frequecy increases,the peak to peak detection time is shorter (just like pitch to midi systems).
Would a breakout of the mag signal before the VG-99 with a phase shifter stompbox pedal help?

No latency doesn't lower with higher pitch.
Strangely enough , I bought a set of Piccolo strings to get better pitch to MIDI result and it doesn't lower the latency.
I could also hear the range limit with Piccolo : D5 (26th fret of a C on a 6 string)

Elantric

#18
The Latency you observe on the COSM modeling, versus the "normal " bass guitar signal is a result of:

Analog to Digital conversion time of the A/D IC

+

DSP processing time - even for "dry signal flow"


+

Digital to Analog conversion time of the D/A IC



=

2.27 milliseconds


If you ever used a Yamaha Digital Mixing board (O2R, O1V, etc) - you may have seen that every channel has its own user assignable Channel Delay in 0.1 millisecond increments.


This is to compensate for phase errors due to various arrival times of the signals to be mixed - as a result various physical mic placement, latency of external processors in the signal chain, etc.

Often you must calculate which processed signal to be mixed in your signal flow  has the longest delay latency, then "add" that same millisecond delay to your other "dry " signals - to eliminate these phase timing errors.


If you don't compensate for these timing delays prior to mixing your audio, you can easily end up sounding like a Brian May "ADA Flanger on Manual Mode" guitar track tone - full of phase errors, and some frequencies you play will "jump" out several dB higher in the mix, while other frequencies are several dB lower. It can feel exactly like you have a dead spot on the neck.

This is what the "Chain Delay" is all about on the VG-99/VB-99 processors - it can be a creative tool, or a life safer!
More here:
https://www.vguitarforums.com/smf/index.php?topic=2911.msg17131#msg17131


fokof

Quote from: Elantric on January 27, 2011, 11:32:17 AM

If you ever used a Yamaha Digital Mixing board (O2R, O1V, etc) - you may have seen that every channel has its own user assignable Channel Delay in 0.1 millisecond increments.


I wish sooooooooooooo much that in a future firmware , they change the 1ms delay in the mixer for a 0,1ms one , 1ms is too much to have a good adjustment.
If they could add one also, in the COSM bass / Mix window , just after the COSM bass and the Normal pickup  , there is a space there , the F3 , wich is yelling for a delay ;)
Not being able to put in phase the mag and the COSM before it is merged together is a total non-sens.
It is my main complain about the VB99.


That and the un-usable Pitch to MIDI ;)

388314

Quote from: Elantric on January 27, 2011, 08:13:43 AM
Read the GR-55 Missing Link thread for a  new unit shipping soon that works with VG-99 and VB-99 that allows you to add many other FX in your "Normal PU" signal chain, in front of the VG/VB/GR processors.

https://www.vguitarforums.com/smf/index.php?topic=2940.0


Sorry, that's not what I meant by inserting a preamp in the chain. What I'd like to do is:

COSM Gtr (or MAG PU) --> Compressor/EQ/Distortion --> Send --> Preamp --> Return --> Speaker SIM --> Reverb/Delay/MoreEQ --> Output

Basically, I would like to try substituting the COSM amps with a real valve preamp.
This is currently only possible via USB, which requires a computer and another soundcard and introduces significant latency (as shown by fokof). Maybe Roland didn't add an analog FX loop because they couldn't reduce the latency to reasonable values.

Oh, and sorry for kind of hijacking the thread...   ;)

Elantric

#21
For what it is worth, If you are a guitar /bass player - the GR-55 provides:

GR-55 COSM Guitar and or COSM Bass (or MAG PU) Guitar Output  --> third party Compressor/EQ/Distortion --> third party  Preamp --> third party  Speaker SIM -->third party  Reverb/Delay/MoreEQ --> third party Amp >Speaker

In other words, you could use the GR-55's Guitar Out jack - feed COSM modeled Guitar or Bass sounds straight to your Line6 POD or stomp boxes feeding your tube amp .


Think of it as an alternative to the Variax or (short lived) Variax Bass






fokof

A recent post on the latency of the SY1000 made me think that I never measured the latency of the OSC synth of the VB99.

Between 1/4'' on engine A and OSC on engine B  > 31ms on LowB string

fokof

That's 5 times better than the OSC on the SY1000 with the latest 1.07 FW update.

Not bad for a 12 year old unit !



aliensporebomb

I rarely used the mag pickups with my VG-99 since my preferred VG controller is a strat with stock single coil pickups (hence - tends to be noisy) but I recently found a klon centaur clone does a really nice thing to the input stage of my SY-1000 so I want to try it on the VG-99 to see if it does a similar thing.  It's interesting the VG/VB does have superior aspects over the "latest and greatest." 
My music projects online at http://www.aliensporebomb.com/

GK Devices:  Roland VG-99, Boss GP-10, Boss SY-1000.