Community: Message List - I got strange noise from amp simulations

Re: RE: I got strange noise from amp simulations

support@line6.com — Tue, 27 Nov 2012 14:39:14 GMT

Although hum and the intermodulation it produces with the guitar notes is sometimes present in old amplifiers with failing filtering capacitors, it is rarely if ever a "good" thing. It's a clear indication that the amp's power supply needs refurbishng.

It has been said that some new amplifiers also exhibit this artifact, but like Dennis, I have never heard one, and I would challenge anyone to demonstrate one. I have a difficult time believing any amp designer would be satisfied with their amp sounding this way if it was meant for commercial sale.

RealZap, you have your opinion, and I have mine. I would bet however, that given a choice between two identical amplifiers tested side-by-side, one with the artifact, and one without, 99% of guitarists would choose to buy the amp without.

Re: RE: I got strange noise from amp simulations

support@line6.com — Tue, 27 Nov 2012 05:15:05 GMT

All I can say is that I never heard a tube amp produce a noise like the HD500 did before I turned down the hum. ymmv

Re: RE: I got strange noise from amp simulations

support@line6.com — Tue, 27 Nov 2012 00:21:12 GMT

hum is sometimes good, and accurate for the amp modeled...

you don't like it... okay... then you probably wouldn't like the real amp... or you'd have it modified to not sound like the real amp...

hum isn't silly... if you take it out, then the sterile lifeless unrealistic remains can often seem cold and unusable to me....

and i could just as easily call that "silly"

it's ok if you don't like it... and some users didn't.... which is why they made it adjustable in the pod hd's...

Re: RE: I got strange noise from amp simulations

support@line6.com — Mon, 26 Nov 2012 23:43:09 GMT

You're welcome Dennis.

L6 themselves should be letting folks know about this tip. In addition, they should be setting the HUM levels to zero by default.

They spoiled many useable amp tones in the "POD X3" with this silly HUM thing.

Re: RE: I got strange noise from amp simulations

support@line6.com — Mon, 26 Nov 2012 22:03:43 GMT

Thanks for the tip about lowering the HUM parameter to remove ghost notes. I was ready to get rid of the HD500 before I read this.

Re: RE: I got strange noise from amp simulations

support@line6.com — Sun, 16 Sep 2012 16:36:09 GMT

I am aware of the option to remove the HUM in the POD HD. I did mention that.

BUT, most likely that only came about in the HD because of the prior user complaints.

Another example of what I meant by that, is Fender does not give the user the option as to where in the signal chain you can place the volume pedal. In fact until a few of us complained, the volume pedal would cut off the reverb trails because the volume pedal was fixed as the last device in the audio chain. How silly of a mistake is that? They've now partially corrected that by placing it after the amplifier, but there still is no option to place it at the front of the signal chain, where at least 50% of users would want it.

I appreciate that L6 got that part right.

Re: RE: I got strange noise from amp simulations

support@line6.com — Sun, 16 Sep 2012 16:10:56 GMT

poynt99 wrote:

. What ticks me off though is the manufacturers are much too often making choices for me on critical aspects of the design, rather than giving me the option to choose. And Fender is no better in this regard.

they do give you the option to choose... on the pod HD units... they're not going to go back and reprogram anything older... just wouldn't be any money in it... and they are afterall a business.

Re: RE: I got strange noise from amp simulations

support@line6.com — Sun, 16 Sep 2012 15:59:41 GMT

It comes down to opinion on the HUM issue.

A great deal of effort and time, and devices (noise gates ring a bell) is usually spent trying to get rid of HUM. Why anyone would actually want to add it to their tone is mind boggling.

The HUM IS what causes the ghost notes everyone on these forums has been complaining about. It's not a question of IF. The line frequency is modulating the signal going through the amplifier, and this modulation produces + and - frequency products. The ghost notes appear as these modulation products, and they are multiples of the line frequency and the fundamental frequency going through the amp from the guitar.

Your preference to have these discordant notes present in your tone is noted, but I'm certain that if 1000 guitar processor users were polled to see if they wanted these notes in their tone after it was demonstrated to them what they sound like, 99% of them would say, "no thanks, I prefer my tone without these ghost notes".

The HUM certainly was added. You can not cleanly remove something unless you added it in the first place. Sure, the amp they "modeled" may have had these ghost notes to some degree, but they didn't model that part of it. They simply added it as a modulation to the signal audio. That's why it can be adjusted in the HD.

The same goes for the transfer function characteristic (amplitude out vs. amplitude in) of all the L6 amplifier "models"; they are essentially all the same. Listen closely to all the amplifiers, except for frequency spectrum differences, they all distort essentially the same way. L6 used one or two generic distortion curves throughout all the models, and placed them in different spots within the amplifier's signal chain. The frequency response of each amp is different, and that's why each amplifier sounds slightly different.

On the other hand, if you listen to the Fender Mustang models, this is not so. Each amplifier has it's own characteristic distortion. That's why Fender has taken over a huge part of the modeled-amplifier market, and why the L6 guitar amps drastically dropped in price within the last year.

Anyway, it all comes down to what sounds good to you. What ticks me off though is the manufacturers are much too often making choices for me on critical aspects of the design, rather than giving me the option to choose. And Fender is no better in this regard.

Re: RE: I got strange noise from amp simulations

support@line6.com — Sun, 16 Sep 2012 13:07:47 GMT

HUM is a good thing... vintage amps had hum... it warms up the sound...

sometimes you have to think in terms of a number of instruments... live or in a studio mix, hum can fill out your sound....

its not always about the sounds of a lonely solo guitar.

if the hum is what you are calling the ghost note issue... then you are also saying that the amps are authentic.....

i prefer authentic to a sterile take on authentic...

you also have to keep in mind that 2 of the same amps can sound different... they can be adjusted differently, have different tubes, biases etc.....

Line6 picked out what they considered to be an amp that had a representative tone...

they didn't "add" hum... they just didn't take it away where it already existed...

they do allow this on the hd's...

i also have to disagree about the x3 being better than the hd's...

there are a few x3 features i miss...

but sound quality isn't one of them....

Re: RE: I got strange noise from amp simulations

support@line6.com — Sat, 15 Sep 2012 15:54:44 GMT

Indeed, the X3 is an older, and in some ways, better unit than the HD. (I find the HD very "fizzy" sounding in comparison)

Incidentally, I can not understand why L6 has not elucidated further on this so-called ghost note issue. 10 minutes after playing with the POD HD unit for the first time, I noticed the "HUM" parameter in the amplifier parameters section. When the HUM control is set to a minimum, the ghost note is eliminated, or at least reduced to the point it can not be heard. Who the hell wants more HUM in their tone anyway?

So from this, it is evident that L6 added a 60Hz (or 50Hz) tone to modulate the amp'd signal to emulate what happens in some amplifiers with poor filtering. First of all it is ridiculous that L6 added this at all, and even more ludicrous that they provided no option to eliminate this in the X3. And as I already mentioned, it is even more surprising that they have not explained what is really causing the effect. In my opinion, several good amplifier models in the X3 were spoiled by L6's oversight on this.

I have not yet tried this to confirm, but I suspect if the line frequency in the setup is changed from 60Hz to 50Hz, the ghost notes pitch will change also.