Zebra2 - LFO sync / rate question, please help!

Official support for: u-he.com
Post Reply New Topic
RELATED
PRODUCTS

Post

I don't understand the relationship between the Sync setting (which can't be turned to an "off" mode) and the Rate knob on the zebra2 LFO's (and similar devices).

Shouldn't they be mutually exclusive, and Sync can be turned off? Or is Sync not meaning "sync LFO to host tempo" but rather sync the triggering to the tempo? If the latter is true, how to you simply make the LFO sync to tempo overall?

I'm used to Rapture, if that helps, where the setup looks almost identical but the implementation is apparently different: is Sync is set to anything other than off, the freq setting of the LFO is disabled, and the value corresponds to a tempo based rhythmic value. If sync is "off," then the freq value determines the LFO rate. That seems pretty standard / straight forward to me. But in zebra2, both are always active, and I'm really not understanding the relationship between the two...what is the value of Rate actually meaning? It goes 0 to 200 with 100 being default. what does that represent? how do you do a simple sync-to-host-tempo LFO setup?

please help!

thanks a ton,
-Michael
Top

Post

The rate control is a multiplier for the cycle setting. Set the LFO to one of the "seconds" modes (0.1s, 1s, 10s) for un-synced LFOs.
Top

Post

Hmm... originally I thought that with the rate control, a value of 200 = 200% a value of 100 = 100% and 0 = 0% (stopped). This doesn't seem to be the case. When I have the cycle set to 1/4 notes, setting the rate to 200 results in a cycle much faster than 1/8 notes. I get 1/8 notes with a rate setting of like 126. :?

Urs... Howard... any thoughts? The manual just says the rate knob scales the cycle speed, it doesn't indicate what the values represent.
Top

Post

justin3am wrote: The manual just says the rate knob scales the cycle speed, it doesn't indicate what the values represent.
If you want a synced LFO clock just leave the rate knob centered and pick any of the clock dividers.
The LFO is "synced" from the beginning .. you "unsync" it by messing with the rate knob.
Hope this helps.
Top

Post

3ee wrote:
justin3am wrote: The manual just says the rate knob scales the cycle speed, it doesn't indicate what the values represent.
If you want a synced LFO clock just leave the rate knob centered and pick any of the clock dividers.
The LFO is "synced" from the beginning .. you "unsync" it by messing with the rate knob.
Hope this helps.
I understand that much, but it would definitely be of interest to me (and possibly others) to know how the scaling of the rate knob works. It'd be useful for people who want to have a smooth transition from one one tempo synced rate to another (e.g. from 1/4 note cycles to 1/16 note cycles). Of course you can select from the list but what if I want an LFO with a cycle 5/4 notes long? I'm fairly certain that I can do that, I just don't know what value I'd need to use.
Top

Post

Sorry, didn't paid attention. :D
justin3am wrote:The rate control is a multiplier for the cycle setting. Set the LFO to one of the "seconds" modes (0.1s, 1s, 10s) for un-synced LFOs.
Meanwhile, I'll try to figure it out.
Top

Post

I'd be interested in your findings, 3ee. I never had the time or patience...
Top

Post

Huh? 200.00 isn't "twice as fast"...? As in 200% of synched rate...? I'm pretty sure it, uhm, should...

If it isn't the it's clearly a bug... just don't know if we should fix it then... might break a hell of a lot of presets...
Top

Post

Urs wrote:Huh? 200.00 isn't "twice as fast"...? As in 200% of synched rate...? I'm pretty sure it, uhm, should...

If it isn't the it's clearly a bug... just don't know if we should fix it then... might break a hell of a lot of presets...
:oops:

Sorry, that was my assumption too. I honestly just discovered this to be the case this morning. I don't know if earlier versions were scaled correctly or not. I can take a look if you like. I think I have an installer for 2.1 and/or 2.3 around here somewhere.
Top

Post

Urs wrote:Huh? 200.00 isn't "twice as fast"...?
It isn't like that... from what I understand, ppl are talking about your different concept of synced LFOs... that's all...
Top

Post

Yeah, this behavior goes all the way back to early versions of v2. I'm in favor of not fixing it but documenting (as well as possible) how the values translate to multiples of the current base cycle. It's actually nice that the Rate control has a much wider range than just x2.

Upon further testing there seems to be some kind of non-linear curve applied to the scaling because a value of 50 doesn't equal 50% of the base cycle.
Top

Post

Note: These settings won't give you 100% "synch". There is always some drift (except at 50, 100 and 200).

Doubles and halves:

8/1 = 200
4/1 = 158.74
2/1 = 125.99
1/1 = 100
1/2 = 79.37
1/4 = between 62.99 and 63.00
1/8 = 50.00
1/16 = between 39.68 and 39.69
1/32 = between 31.48 and 31.49

A few triples and thirds:

3/1 = 144.22
3/2 = 114.47
2/3 = 87.36
1/3 = between 69.33 and 69.34

Puzzle for the weekend: What little experiment did I set up to get such precise figures? A big :tu: for the first person to get the correct answer...

Does anyone fancy working out 5/4 etc. etc.? :wink:
Last edited by Howard on Sun May 15, 2011 9:52 am, edited 3 times in total.
Top

Post

Howard wrote:Puzzle for the weekend: What little experiment did I set up to get such precise figures?
I've been noodling on this now for a few hours and haven't come up with (to me at least) a precise enough method to get .01 accuracy as you seem to have done. :)

I initially tried modulating LFO1 with LFO2 but with a phase shift of 50.00 so that when the waves were perfectly in sync they'd be out of phase and produce no modulation. But for some reason this didn't seem to work out. I then tried a few attempts to use the arp + modulation of an OSCs amp to work out the sync but quickly realized this wasn't fine enough again.

I'm very curious to learn of your solution when you finally divulge its secrets! Maybe a small hint to those of us doing our homework?

Finally, do those measurements work for the Attack/Loop/Release knobs associated with the MSEGs?
Top

Post

Howard wrote: Puzzle for the weekend: What little experiment did I set up to get such precise figures? A big :tu: for the first person to get the correct answer...

Does anyone fancy working out 5/4 etc. etc.? :wink:
I don't know what you did to find out, but from your numbers it wasn't hard to find the formula:

SpeedScale = (KnobValue/100) ^ 3 (ie. the cube of a hundredth of the knob value)

-- or respectively --

KnobValue = 100 * SpeedScale ^ (1/3) (ie. 100 times the cube root of the speed scaling factor)

where KnobValue is the value of the Rate knob and SpeedScale is the scaling factor of the LFO frequency.

I even went as far as creating a web page with javascript that can be used to find the actual speed scaling factor given the knob's value (and vice versa). Might come in handy at times: http://zebra.andreloker.de/ :D

The site is pretty much self-contained, relying only on the Google CDN for jQuery, so you can simply save the web page and copy it anywhere you want.

As to answer your question: if you want to speed up the sync value by 5/4, set the knob to 107.72. If instead you want to scale the duration by 5/4, use 92.83.

Have fun,
Andre

P.S.: if anybody is feeling overly generous - I'd happily take an NFR copy of FilterScape or MFM (I already have Zebra, ACE and Uhbik) :-)
Top

Post

bmrzycki wrote:
Howard wrote:Puzzle for the weekend: What little experiment did I set up to get such precise figures?
I'm very curious to learn of your solution when you finally divulge its secrets!
Sorry Brian, I didn't see your reply until now. AND I have no idea what I did right now, it's too long ago (gets coat)! However, I revisit this thread when I get time, OK?
Top
Post Reply

Return to “u-he”