POD HD 500 - Tremolo Modes

POD HD 500 - Tremolo Modes

The POD HD 500 offers several tremolo modes. 

 - Optical Tremolo  - Based on the optical circuits found in Fender amps such as the Deluxe Reverb

 - Bias Tremolo - Based on the 1960 VOX AC-15 Tremolo

 - Panning Tremolo - Used for panning back and forth between 2 speakers in stereo.

 - Pattern Tremolo - Used for creating rhythmic patterns.

Optical mode is pretty good on the HD-500. It is on par with some of the optical Tremolos I've heard, the wave shape it gives you is akin to the wave shape on the Demeter Tremulator, which models the Tremolo off of the Fender Twin optical trem.

Optical Tremolo - Shape Control Adjustments and Corresponding Wave Shapes

Center we can see is the most even rise and fall with left and right being a more gradual rise and fall on the start or ending of the wave. 

Next comes Bias mode... This shape looks quite a bit different from the Bias modes I've seen previously (Typically a sine wave). The manual states this is based off the Bias Tremolo in a 1960 Vox AC-15. So this may account for the difference, I don't know. But either way. This is the reality of what you get.

Bias Tremolo - Shape Control Adjustments and Corresponding Waveshapes

Now this was taken in stereo... You'll note optical mode keeps things in sync on left and right speaker. But here we see that not only does Bias mode NOT do this, but it doesn't even alternate equally from left to right either shape or time wise! One channel is like half the speed of the other one. 

So perhaps the wave shape is correct here (Can't say as I don't have a reference amp to compare), but the AC-15 was a single speaker amp from what I can tel which means no stereo implementation on the original. Which would mean that Line 6 came up with this particular stereo implementation on their own.

To me it just sounds weird.  To the ear it is not in any way smooth. Listening to a reference on Youtube, they don't sound alike to my ears.

Next we have panning mode, which in theory should pan back and forth between the left and right speaker. Here it gets really whacky.

Now Triangle is exactly as you expect it, and it sounds good. Square is also as you expect it and sounds good as well.

But all be damned if that sine wave looks and sounds a little weird to me :) Sine sounds not smooth at all, and as we can see by the wave shape above, it's really not a sine wave. The sharp peak there means that instead of panning equally and smoothly back and forth you get a very sharp volume peak on each speaker which makes you feel a little drunk.

If that's your thing, then you'll love it. For those looking for a decently smooth sweep from speaker to speaker, the closest you are going to get here is a triangle wave. 

Lastly we have Pattern Tremolo. I think the implementation in the HD-500 of this is awesome.

They basically give you 4 steps, which equal specific lengths of time. You can then choose how many trem cycles you want in each step. From 1 to 16. You also have the ability to skip, or mute, or include complete maxed out volume on the entire step.

This is a choppy square wave type tremolo on Pattern trem mode. Line 6 makes it easy to work with, and easy to understand. Very nice.

The glaring omission on the HD-500 is the inclusion of Harmonic Tremolo. So if you are interested in that look elsewhere.

Slowest Speed: ~897 ms/cycle

Fastest Speed: ~63 ms/cycle

Pro's

 - Optical tremolo is great.

 - Adjustment for volume sensitivity in essence gives you an envelop so your playing attack controls the speed of the tremolo

- Pattern Tremolo is great and implemented well

Con's

 - The Bias tremolo may not be what you are looking for if you are looking for a smooth deep tremolo.

 - Sine wave in Panning mode isn't a sine wave and undulates rather sharply on one side or the other, it is not that smooth, and sounds a bit drunk.