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Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by indigobjn on 2011-10-14 07:28:31

Hi there. I've some problems with my guitar sustain. I'm using POD HD400. To reduce noise while using high gain amp models, I used noise gate and NR by setting the threshold value about -35 only. But this reduces the guitar sustain. The sound die out 2-3 seconds after I play some notes. While increasing the threshold value to -70DB, the sustain's pretty good. How can I reduce the noise level maintain a good guitar sustain at the same time?



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by Nick_Mattocks on 2011-10-14 07:38:01

With the current noise gate your options are fairly limited I'm afraid.  The answer may be to reduce the amount of gain you are using and then your noise gate threshold may be able to be relaxed. 

Quite often the amount of gain used on recordings where notes have good sustain properties is a lot less than we might imagine.

You may need to spend some time further attempting to balance the amount of gain and the noise gate threshold and whilst that seems a bit lame as an answer that may be your only option with regard to the internal noise gate in the HD400.  You could also try an external noise gate solution between the guitar and the HD400 input.

Nick



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by indigobjn on 2011-10-14 08:03:35

Thanks for your reply Nick . I will try balancing the gain and noise gate threshold values.

One more thing I forgot to mention. The noise seem to reduce almost completely when I rest my hands on the bridge of my guitar or touch my guitar's strings or even touch any of the POD hd400's switches while playing with high gain and high noise gate threshold value. Does this mean there is some problem with the guitar's wiring or some kind of earthing/grounding problems with my guitar or at home?



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by jimsreynolds on 2011-10-14 08:05:23

It may sound obvious but the trick is to kill as much noise as possible before it reaches the HD ... which is generally a fairly quiet unit even with high gain amp models

The less noise the HD gate has to contend with,  the more natural the decay will sound.   When you use gates to fight a relatively low level of noise then they play very nicely High Gain sounds.

Following Nick's suggestion, to get an external gate, could help but I would think first in terms of

  • Making sure I had a decent quality undamaged cable - cheap cables can give you mondo noise even when kinked or trodden on.

  • Making sure the input jack on my guitar was clean and gripping the plug well.  You can carefully unscrew most of them for cleaning and re-tensioning, just take care not to yank wires).  Get some switch/pot cleaning spray from an electronics store and apply it as per instructions if you don't want to unscrew anything.

  • If the electronics on my guitar were a bit old or had been hacked around (mods, pickup changes etc) then checking for ground issues there can help.

  • If the guitar is single coil, think about shielding the pickup cavity with conductive paint/foil etc.

  • Humbuckers are obviously quieter than single coils.  Actives even more so.   For High gain settings, single coils will almost always be more audibly noisy - I have a squier tele that is perfectly usable with moderate gain Marshall sounds and is fairly unusable on v. high gain models.

Even with an external gate, if your guitar and cable(s) are noisy then you will still get the unnatural decay.



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by jimsreynolds on 2011-10-14 08:23:50

Oddly, no.  It is exactly the opposite.  Your body generates/focuses noise which is then picked up by the guitar.  Touching the guitar effectively earth's you, via the strings and a wire from the bridge back to the earthing in the control cavity.

This article has more details.

http://www.guitarnuts.com/technical/noisebucket.php

Anothergood argument for shielding your guitar I guess.  Same site has a fairly extreme example of how to do this comprehensively.

http://www.guitarnuts.com/wiring/shielding/shield3.php

HTH

JIM



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by indigobjn on 2011-10-14 08:49:50

Thanks JIM for your reply. I have plugged my guitar direct into the amp and it still generates noise. That means HD400 is quieter like you said.

Touching the guitar effectively earth's you, via the strings and a wire from the bridge back to the earthing in the control cavity. The noise gets reduced only if I touch any metallic parts of my guitar not the body. The links you just posted would help sort this out.

I have problems with my guitar sustain as well. I'm using Ibanez XP300FX. It has a fixed bridge without any locking systems. What might be the problem?



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by indigobjn on 2011-10-14 08:57:55

All the equipments are new. Guitar Ibanez XP300FX, cables, POD HD400, amps and all. This guitar has humbuckers. But this guitar had some problems with volume knob. The volume didn't go zero. Turning the volume knob didn't have any effect on the volume. I took it to the technician and he fixed it. Is there something to do with it getting fixed badly?



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by jimsreynolds on 2011-10-14 09:03:33

Hmm, just pulled up the Ibanez page for that model.  It has humbucking pickups ... I would not expect them to be particularly noisy.  I do wonder if you have a bad cable or electrics?  It maybe that someone on the Ibanez forum can comment on what you should expect from the guitar in case there is a known issue. 

On the sustain thing: part of it comes from the wood of the guitar and construction and there is not a lot you can do about that.  I would check that the pickups are not too close to the strings ... if they are they can actually choke off your sustain.  Try lowering them by a few of screw turns (keep track of how many so you can adjust back if needs be) and see if that helps.

If the action on the guitar is well set then that will help sustain also.  For open strings you could change the nut for bone/tusq for increased sustain but that does not really help with fretted notes.  The bridge could also be replaced, if it is mega cheap.


Also, make sure that your strings are not ancient.  If they are more than a couple of months old and you play regularly, change them.  Clean them after playing and they will last better.  Old strings lose a lot of sustain.

Really though, based on your description, I think there may be something with your guitar electrics.  Do you have another guitar you can test with, or borrow one off a mate.

Finally, try it all again through the HD with headphones on and see how it sounds - this eliminates weirdness with your amp.



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by jimsreynolds on 2011-10-14 09:15:57

Just one more thing .... have the electrics in your guitar been modified in any way?  Apparently the pickups have a coil tap wire - this allows a single coil mode from humbucking pickups.  If this has been soldered incorrectly so that your pickups are running as single coils, that would help explain the noise.

Just a thought ...



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by jimsreynolds on 2011-10-14 09:20:37

Yes, I think he may have done something wrong.   I think he has wired up the pickups now so they are in single coil mode.  The INF3/INF4 pickups on that guitar apparently have a coil tap connection .  If he has wired the pickups incorrectly, you may be running in single coil mode.  That would explain the extra hum.

More details here on the pickup wiring....http://www.jemsite.com/forums/f35/inf-4-and-4-pickups-question-106156.html

Asalways though, not 100% certain without seeing/hearing so maybe suggest it to the tech before you beat him to death with the guitar.



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by indigobjn on 2011-10-14 19:15:47

The technician said there was some loose connection in the volume POT and said he fixed it. I think he didn't touch any of the pickup wires.

I did an experiment mention in the link you provided http://www.guitarnuts.com/technical/noisebucket.phpand found that my body is generating the noise which is picked up by the guitar pickups. Does this mean the guitar electrics are ok and it's not generating the noise at all?



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by jimsreynolds on 2011-10-15 01:40:09

The point of humbuckers us that they are meant to reject that kind of hum. I can't say for definite that there is an issue but I still think you should find another guitar to compare with. If you don't have access.to one, go to a store and 'test' an amp with your guitar and one of theirs :)



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by Nick_Mattocks on 2011-10-15 04:27:44

The kind of grounding issue that you're experiencing with your guitar (in that I think what you'e saying is that you're getting a 50Hz or 60Hz hum which reduces when you touch the guitar strings ot the metalwork of the bridge) can vary from venue to venue.

For instance at home here, my guitars in general all tend to be 100% silent when I plug in to my HD500 whether it's connected to an amp or whether I'm using it as a free-standing unit with headphones.  Touching any metalwork on the guitar doesn't cause any kind of click or buzz or reduction in buzz (not that there is any buzz).

However I know that if I take the sme guitar, HD500 and headphones to another venue I go to quite a bit, that I will encounter some buzz if I let go of the guitar's strings.  

The issue is due to a lack of a good ground at the other venue.  Here in the UK, of the three connections in a typical mains plug (Live, Neutral and Earth - that's what we call 'ground' here ), Neutral is bonded to the Earth connection back at the distribution board/meter where it enters the property.   Depending on the age, construction and earthing arrangements at the property, whilst the Earth connection hase to be good enough to guarantee electrical safety by law, it may not be perfect in terms of rejecting mains borne hum.   A good solid Earth connection would probably involve having a long metal rod of about 1- 2m in length being sunk into the ground near the property and preferably into soft, damp soil.  Older proprties may have water and gas delivered in underground metal pipework and bonding the proerty's Earth connection to these pipes would often do the same job as a metal spike in the ground, however these days water and gas is often delivered to the perimiter of the property in plastic pipes or plastic covered pipes which of course does not provide good contact with the ground.

The wiring within a property may even pick up a little AC current in the Earth wiring itself over a distance because of the effect of induction where theEarth wire runs very closely alongside the Live/Neutral cables which are happily delivering AC at up to 240v at 50Hz or 60Hz depending on where you are in the world.  The constant switching of polarity can generate an opposite switching of polarity in nearby wires causing electrons to flow in a similar way to how a transformer works.  When this gets into an audio circuit it can generate hum - and it only needs to be a tiny amount of voltage at just a few millivolts to create hum in a sensitive audio circuit.  When you touch the strings on your guitar, you simply provide a slightly better localised path to 'ground' for the tiny amount of current present.

I have proved this when I lived in an old property which had been gutted and provided with new internal wiring and new water and gas supplies in plastic pipes or plastic covered pipes.  My home studio gear started off being quite humworthy until I started tracking the causes down.  I found several ground loops which I resolved, but after all of that I found I still had some residual hum, so I installed a proper Earth Spike in the soil just outside the room I was using as my studio and used that as a good local ground.  This cured the issue with hum.   However as I was curious, I placed a test meter set to a low range for AC voltage in between the normal Earth connection and my external Earth Spike connection and found there was definitely a small amount of AC - again only a few millivolts - present in the copper earth wiring that ran with the mains Live and Neutral wiring, but it was enough to give rise to hum in any sensitive audio circuit. In terms of the length of copper wire involved was probably only about 50m twice for the 13amp mains outlets and the same again for the lighting circuits plus a bit for a dedicated electric cooker circuit and a bit for a dedicated immersion heater for hot water.  At that property the electricity was supplied by medium high voltage overhead wires with a transformer on a pole which dropped it to three phases of 240v each, of which my property received one phase.   Additionally within 100m of the property there were two sets of high voltage power lines to the local power distribution site about three miles away.  Those things give off a lot of EMI and it can be picked up on an old style long wave AM radio easily at those sorts of distances.  This was a rurally located property.  I now live not too far away from there but on the edge of the local town, where the power supply is generally cleaner and more relaible to start with, but where the power lines are all underground and where there are no overhead pylons carrying high voltage power lines within a few miles, so mains borne interference is rare and grounding issues are non-existent.

It doesn't indicate that the electricity supply is in any way faulty or unsafe in terms of grounding, but in terms of audible noise it might indicate that the ground connection could be improved.

Humbuckers do help in rejecting sources of Electro-Magnetic Interfereence 'hum' created by the local environment which might be caused by fluorescent lighting, cathode ray tube TVs or monitors, but humbuckers are not totally immune to this kind of thing.  Low impedance active pickups tend to be much, much better at rejecting hum like this than any passive coil based pickups are.

As Jim says, you should rule out potential problems with your guitar by comparing with another known to be good guitar attached to your rig.

You may find that using your gear in a different room or from an alternate power outlet on the wall might help reduce the problem.  You may also find that connecting a 1/4" instrument cable between the output of the HD500 and an amp which is plugged in to the wall but not turned on, but which is connected to ground, will provide the ground connection your HD500 and guitar need when you are monitoring by using headphones, or if you're using the HD500 with an amp, make sure that there is a single point of contact for ground and that all connected devices are plugged into the same power strip.

Use good quality instrument cables which are flexible, not prone to capacitance or microphony issues, do not exceed 20ft max and which provide excellent shielding properties.  Try not to let instrument cables become coiled up and make sure you keep any wall-wart type power supplies well away from signal cables.  Wherever possible do not run signal cables alongside power cables and if you need a signal cable to cross a power cable, try and make sure they cross at ninety degrees.

Nick



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by indigobjn on 2011-10-16 01:33:10

Yeah humbuckers are meant to reject that kind of hums. That's a very good idea to take my guitar to the store and compare mine with other similar models there. Will visit soon. Thank You Jim



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by indigobjn on 2011-10-16 01:50:15

Hi Nick. You are very knowledgeable on grounding issues. I read your reply. I took the whole sets of equipments to the other room. In fact, I experimented connecting those equipments in all of my rooms. I found the hum reduced by a fair amount in one the rooms but at the other rooms it still gave the same noise.

And yes, The power supply cables of both amp and HD400 run almost side by side with the guitar signal cables while I play since those power cables are fed via the extension cord from the same power strip. That may have induced some ac signals on those signal cables and produced hum. I'll try and maintain 90 deg. if they cross over.

Humbuckers are meant to reject noise/hum. So, I myself checked to see if there's any loose connection in my guitar's wiring. Everything was just fine. This means the grounding at my home is just not perfect, at least not uniform room to room.

Thank You so very much for your help . I will try out all I can do and will need your help if that doesn't work.



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by Nick_Mattocks on 2011-10-16 10:58:02

The HD500 power supply might give you a lot of hum if it is at all close to any signal cable.  I find the older X3/M13/Variax XPS type power supply incredibly noisy if my signal cables are near it, so I always make sure to keep the signal cables at least three feet away. The HD500 is capable of adding noise if it's too close to any signal cable as well. 

The fact that the level of hum reduced in another room in your house does indicate to me that there might be some local environmemtal cause in your house which might be ground related, related to the type of lighting or related to something else entirely.   It doesn't really matter too much that the power cables run together; it's more of a problem when they run near to your signal cables.

Nick



Re: Reduction in Guitar sustain with Noise gates while using high gain Amp models.
by hortond on 2012-01-06 16:31:42

Hi Nick,

You said that HD500 power supply might give a lot of hum, if that is so, would a HumX device eliminate the problem or can we just improvise it by covering it with a shielding foil?




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