Signal leakage

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- April 18, 2009 at 9:47 pm #106186
  
  ThreeFingersOfLove
  Participant
  
  Hello,
  
  I have noticed that in many presets that use some kind of modulation pattern there is an audible leakage of this pattern even when no signal is present. For instance, presets 3414, 3329, 3328, 3327, 3322, 3320, 3319, 3318, 3317, 3316, 3314, 3313, 3312, 3311 (all have some kind of leakage – I can definitely hear some LFO modulation in all of these patterns). In preset 3237, the leakage starts after the audio signal gets below a certain threshold – it's not audible when the signal is present… Why is this happening? I have other FX units here and they are dead-silent even when there are such modulations… 🙁
  
  I also noticed that in a lot of presets that use some kind of feedback, there is an audible amount of noise – it seems to me that in both cases the H-8000 is trying to apply its algorithm to whatever signal is present – even if it's a tiny amount of noise (maybe from the A/D converters?). I was wondering if there is a way to apply a threshold (maybe a gate or something) that would prevent such signals from leaking… It would be even cooler if this was some global parameter in the H-8000 and not in the algorithm, lest it consumes computational resources..
  
  Regards,
  
  Yannis
- April 29, 2009 at 9:04 am #118546
  
  ThreeFingersOfLove
  Participant
  
  Bump… 🙁
- April 29, 2009 at 3:03 pm #118550
  
  IDeangelis
  Member
  
  HI Yannis
  
  I do not understand what you exactly mean by "signal leakage" here.
  
  Are you listening those panning presets with the correct routing and audio setup?
  
  Many of them are stereo in/quad out and should only be used in a quad speaker setup.
  
  Regarding the noise, it may depend on the inut level you are using. A gate can be applied on a per_preset basis, building it in Vsigfile.
  
  all the best
  
  I
- April 30, 2009 at 6:59 pm #118552
  
  ThreeFingersOfLove
  Participant
  
  Hi Italo,
  
  by "signal leakage" I mean that I can hear the modulation pattern applied to whatever is there when no audio signal is present. It's not dead quite, there is always some kind of noise, so when I load these presets I hear the modulation pattern. When audio is coming in, its level is much higher than the noise level, so it's not possible to hear anything. As soon as audio dies away, the modulation pattern is there again.
  
  I haven't listened to these patches in quad or surround, but I don't see how that could affect this signal leakage – it exists even in stereo configurations.
  
  I tend to use the preamp gain in the H-8000 FW. I often boost the signal so as to have 3-4 LEDs in the meter, as you suggested. So when there is this boost, noise is also boosted and I can hear the modulation pattern. Obviously it's there even if no gain is applied – it's just not audible. This is why I suggested some kind of gate that would open only after a certain threshold is passed.
  
  Would you recommend an external pre-amplifier for this?
  
  Regards,
  Yannis
- April 30, 2009 at 7:13 pm #129699
  
  IDeangelis
  Member
  
  I understand now, Yannis, Thank you.
  
  You are hearing background noise.
  
  You should make sure about the following:
  
  -the unit analog I/O should be properly wired for what is the type of signal you are using, balanced/unbalanced and -20dB instrument level or +4dB line level signals.
  
  -using *studio grade* professional audio balanced shielded cables, such as Canare, Mogami, Belden is greatly recommended, rather than generic guitar/mic cables. These companies make the best cables in the industry and are used to wire professional studios. I use Belden.
  
  The optimal performance (signal/noise ratio – audio clarity – high levels) is obtained with full balanced I/O, running +4dB line level signals. These types of signals are pre_amplified. I have no knowledge of what exactly you feed the unit with and how, but I assume you are using pre_amped sources for +4dB signals.
  
  all the best
  
  I
- April 30, 2009 at 7:44 pm #129700
  
  ThreeFingersOfLove
  Participant
  
  Hi Italo,
  
  thanks for the swift reply. I use synthesizers – these are mostly unbalanced sources. The one I have here now is an Alesis Andromeda, unbalanced audio outs (into the H-8000's analog ins) *but* the cables are balanced and generic mic cables with Neutrik connectors. I know that there is a volume loss here…
  
  I am a little confused about generic mic cables versus professional shielded cables. I have been eying some VoVox cables, check them out at:
  
  http://www.thomann.de/gr/vovox_protect_s200_xlrxlr.htm
  
  The problem is that they still advertise them "for microphone or balanced line interconnects"… Do you have a link with the ones you use?
  
  Regards,
  
  Yannis
- May 4, 2009 at 9:01 am #129710
  
  IDeangelis
  Member
  
  Hi Yannis
  
  advertisement! [:'(]
  
  I use Belden 8451 balanced cables. They are under the Paired Cables section of the Belden website:
  
  http://www.belden.com/03Products/03_MasterCatalogSection.cfm
  
  cheers
  
  I
- October 19, 2009 at 9:53 pm #130410
  
  ThreeFingersOfLove
  Participant
  
  Hi,
  
  preset #3910 has a signal leakage. In the Reverb tab, if I set the mod depth and mod rate to zero, then this signal doesn't disappear but at least, it is consistent. It's not the cables or some other fancy stuff. If I select a different preset, it's *ultra* quiet. It's a noise which is IN the algorithm.
  
  Is there a way to remove this? It's driving me crazy because it's apparent with and without any signal present. Now that I am typing this, I can hear it from the other side of the room. 🙁
  
  Regards,
  
  Yannis
- October 19, 2009 at 10:28 pm #130411
  
  nickrose
  Moderator
  Eventide Staff
  
  Hi Yannis
  
  I've added it to the list of things to be looked at for the next release. Until then, I suggest you don't use this preset.
- October 20, 2009 at 7:27 am #130416
  
  ThreeFingersOfLove
  Participant
  
  Hi Nick,
  
  you are killing me 🙁 At least I have to thank you for making a note. In my first post in this thread, I have mentioned more presets which exhibit the same behavior. Maybe whoever gets to check this bug (?) will want to see more presets doing the same.
  
  Regards,
  
  Yannis.
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