Latency with digital fx in paralell loop - solutions?

Hi folks,

as I own a nice Eventide hardware fx unit I wanted to use it in the loops of my Diezel amps.

Unfortunately I cannot use it in the parallel fx loop as the ADDA conversion will feed the effected signal back to the amps mixing stage with some latency. That, as most of you may know, will result in a sort of combfiltering effect that makes this way of using the fx unit pretty much useless.

On the other hand one needs to use sample rates over 48khz in the serial loop as the degradation of the signal after the conversion will be audible quite clearly which in turn limits the number and type of presets the unit can handle at these rates. Nevertheless the overall sound is of course better as in the parallel fx loop but still different in harmonics and dynamics.

So my question is if anyone of you has found a smart solution to have a digital fx in the parallel loop of a tube amp without said artifacts / problems?

Thanks a lot.

JTM

Kill dry?

Definitely kill dry. 100% wet signal. If that's not possible serial with true bypass loop or a new fx unit.

kill dry

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Well then you can stick it in the serial loops all the same, right?

JTM: You will always have some latency added by a digital device, no way around that really. Also I find it hard to believe you really notice a sample rate increase from 44.1 to 48kHz in your digital FX unit... especially for guitar and the frequecnies it covers.

kahawe":50vniubm said:

kill dry

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Well then you can stick it in the serial loops all the same, right?

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No. Kill dry means that the effect unit only outputs wet signal (only signal effect by effects) so you will not get any phasing issues when run it in the parallel loop. Running a unit set to kill dry in the serial loop will cut out the original signal, which for example would sound really weird with delay and reverb.

Other than that, JTM, you can try messing input/output levels on your effects unit and with the channel volumes (since these determine the level of the loops) and see if you still notice a difference in sound/dynamic. Often these units get set up incorrectly and people blame the bad sound on the unit, but I also know that some can hear a difference in the most slightest changes in the signal chain.

Lastly I can't offer any other solution, but some wisdom: Nobody will hear a difference and nobody knows that it could sound different. Maybe you won't even hear a difference when you play loud with the band. This is assuming you play mainly in a band.

Kev":2jfk1oc5 said:

No. Kill dry means that the effect unit only outputs wet signal (only signal effect by effects) so you will not get any phasing issues when run it in the parallel loop. Running a unit set to kill dry in the serial loop will cut out the original signal, which for example would sound really weird with delay and reverb.

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I meant it the other way around. Running the FX set to 100% kill-dry in the parallel loop would be pretty much the same as running the unit not-100%-kill-dry in the serial loop - given you set the parallel-loop balance to what you set the unit in the serial loop. It's the same end result of a mixed wet and dry signal, just in one case you are doing it all inside the FX in the other case in the amp.

So he could just as well stick it in the serial loop and not worry anymore (e.g. if he didn't have a kill-dry on the FX), it does not HAVE to be in the parallel loop.

Kill dry and parallel will sound best.

kahawe":3twv53bw said:

Kev":3twv53bw said:

No. Kill dry means that the effect unit only outputs wet signal (only signal effect by effects) so you will not get any phasing issues when run it in the parallel loop. Running a unit set to kill dry in the serial loop will cut out the original signal, which for example would sound really weird with delay and reverb.

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I meant it the other way around. Running the FX set to 100% kill-dry in the parallel loop would be pretty much the same as running the unit not-100%-kill-dry in the serial loop - given you set the parallel-loop balance to what you set the unit in the serial loop. It's the same end result of a mixed wet and dry signal, just in one case you are doing it all inside the FX in the other case in the amp.

So he could just as well stick it in the serial loop and not worry anymore (e.g. if he didn't have a kill-dry on the FX), it does not HAVE to be in the parallel loop.

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It's not the same. If the FX does not have analog dry-through (which I believe describes all Eventide FXs), then running it in the serial loop means that all of the signal is run through an AD/DA conversion. With killdry in a parallel loop, the "dry" signal is kept away from any AD/DA conversions. I don't think that AD/DA conversions necessarily are terrible, but if he wants to avoid converting the dry signal, the parallel loop is the way to go.

Hi folks,

Thanks for all the feedback, yet there are issues with your proposals.

Although there is an option to only put out a 100% wet signal from the Eventide's internal mixer ( sort of the "kill dry") the Eventide will always convert the signal A to D and there is no way I know of to bypass the conversion.

And that my friends is exactly the issue here:
Even with a kill dry, the time it takes to convert A -> D and delivering the signal on the outputs due to the D-> A conversion will be the time the wet signal is "too late" when mixed back with the dry signal from the amp. You get a phase misalignment between wet and dry that amounts to the overall latency of both conversions. Now suppose this is about 3ms for each conversion it will be like 6ms in the end. That is already audible as sort of a "doubler" effect.

I think the Eventide way of doing the processing is fine for studio type of work but in a parallel loop of an amp it definitely causes those problems.
Looks like I need to use it in the serial loop....

BTW: Actually I went to 88khz sample rate. Makes a huge difference to 44/48khz, less grainy and signal dynamics feel like being less affected.

Hi all,

looks like I found the issue.

Of course when you set the mix to a 100% wet you should effectively get rid of the phase issue.

Now it looks like some of the presets in the Eventide make us of the dry but converted signal.
That means there are in fact three signals, the converted but dry, the converted and processed plus the dry signal from the amp.

Looks like I need to edit the presets such that the converted/dry is not take into account.
Eventide has a software for PC called VSIG to make do some deep editing like this.....

Thanks for your input, appreciated.

JTM

I use a TC Electronic G-System with my Diezel Herbert and Diezel 4x12. I have noticed an EXTREME difference in tonality, and the pristineness for lack of better word, of the G-System when using Parallel versus Serial.

Herbert Manual says use Parallel.
TC Manual (and TC "White Pages") says use Serial.

I let my ear be my guide, but WOW what a difference from one loop to the other!
If you use parallel make sure it's up to ten on the little dial on the back (ie. maxed out!)

The TC sounds choked, muddy, flat and unresponsive on the Serial Loop.

MikeToddOnline":1on9zm31 said:

I use a TC Electronic G-System with my Diezel Herbert and Diezel 4x12. I have noticed an EXTREME difference in tonality, and the pristineness for lack of better word, of the G-System when using Parallel versus Serial.

The TC sounds choked, muddy, flat and unresponsive on the Serial Loop.

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For sure you will hear a difference. On the parallel loop you have a split setup like the signal will be sent out to the FX, converted and then mixed with the dry sound from the preamp. Using the serial loop do not have the dry signal anymore. You send the whole signal out to the FX where it will be ADDA converted and signal quality is definitely suffering when using mediocre converters and low sampling rates. Just look at the prices for professional converters for recording studios with brands like Forsell etc. and you know what I am talking about.

I took the time to look up the internal sample rate of the G-System and it is 44.1khz and that cannot be altered as I understand.
While you would think that should be ok as it is the sampling rate used on audio CDs, it is not.

I have the luxury on my Eventides to go from 44.1 to 96k master sampling rate (although some presets will not work on the higher rates).
and I can tell you the difference between 44.1 and 88.2 is day and night. Now add on top the parallel setup and that is the best you can get.

BTW: I had some TC G-Major and it really sucked tone. Sold it very quick and haven't heard too much good things about the G-System, too as there have been issues with the basic design of the unit. For the price of a new G-System I bought a used Eventide 7000. More than happy with the Eventide, never going back....

So you don't need the effects you can only use with the serial loop?

MikeToddOnline":31abe7xy said:

I use a TC Electronic G-System

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That's a well known problem with the g-system and you can find tons of other users reporting similar issues one way or the other.

Bato":31xcwcvr said:

So you don't need the effects you can only use with the serial loop?

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Actually I find out that you can use it in the parallel loop to, but on top of the kill dry I need to eliminate the converted dry signal that some presets use.
With the VSIG software by Eventide you can download the preset to the computer via a serial to usb adapter. In VSIG you get a graphical representation of the algorithms with all the nodes an connetctions and you just need to locate the converted dry route and disconnect it. Then I send the preset back to the Eventide 7000 and save it.
Quite a cool way to edit patches....and man, the 7000 is deep....really the most powerful FX unit I ever came across....

kahawe":17hbfacp said:

MikeToddOnline":17hbfacp said:

I use a TC Electronic G-System

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That's a well known problem with the g-system and you can find tons of other users reporting similar issues one way or the other.

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When you read up on many of the units that TC has created for the last 15 years you realize that they built and sold a lot of crap. Although I think their latest pedals are top notch, most of the guitar related digital FX units have huge design flaws...

The problem for guitarists is simply that nowadays you don't have many companies around that really produce 19" FX units with a focus on guitar.
Either there are smart pedals like the Eventide H9 or the Strymon stuff. I tested both and I can definitely say that none of them is a replacement for good old Eventide rack unit.

While the H9 sounded good and had an Ipad interface the problem for me was that it could only run one algo at a time, that means i.e. you get an effect like a chorus or a phaser with some reverb in one algo. Now imagine you would like to add delay....forget about it!

In fact they will tell you that you need to buy another H9 to run a delay algo on the second one and then chain it? Nice idea to push your sales....And no one tells you about there being no digital connection between two H9's, which in turn means you do the ADDA conversion on the first unit, patch the analog out into the second units analog in and there the whole ADDA conversion will be done again. Perfect!! On top they will sell you an algo for 20$. Those algo's are actually mostly taken from the old 19" rack units so they are already developed and simply recycled...Easy money.... If you buy all the algos you will pay more than for a used 7000 or similar...You simply can't make that shit up....

While I thought the Strymon stuff was reliable and easy to use I found it too sterile.
I am back now with the Eventide 7000 and I think this is the best investment I have done in a long time...