What is the dynamic range of the POD HD 500x?

[bjnette]

I wonder if this has been published,

or has anyone worked it out?

[pfsmith0]

First you'll have to define dynamic range. Dynamic range can be defined as max usable input signal level - min input usable signal (a telecom/audio way of looking at things). Or it could be the difference between the max output signal and the max THD/spur/noise output components (a data converter way of looking at things,

 

The biggest signal could be 0dBFS, or maybe the 10% THD point (which seems to be a standard in some audio applications) which is ideally is +2dBFS. I measured the 0dBFS point in this post here, which shows 8.3Vpp for the Guitar Input. Other inputs/outputs are also listed.

 

The smallest signal is limited by the noise floor. Shall we use A-weighted noise or something else? Should the minimum signal be the noise floor itself or +3dB above the noise floor? Or some other level above the noise floor? 10-12dB is generally considered a good minimal SNR before humans consider a voice unusable. Does guitar have the same psycho-acoustic limit?

 

All this to say, dynamic range is a "fuzzy" spec and not an industry standard. I'm not trying to make this more difficult than it is, but I need some guidance on what to give you. The max signal portion is already done in the thread listed above. The min signal portion has yet to be done, but is easy to measured with any DAW. But I mainly need to know if you want A-weighted noise or not. I'm thinking maybe yes. Or maybe there's another standard that should be used?

[cruisinon2]

I'm not trying to make this more difficult than it is, but I need some guidance on what to give you. The max signal portion is already done in the thread listed above. The min signal portion has yet to be done, but is easy to measured with any DAW. But I mainly need to know if you want A-weighted noise or not. I'm thinking maybe yes. Or maybe there's another standard that should be used?

I understand curiosity for curiosity's sake....but that aside, what would one do with this information?

[pfsmith0]

I'm thinking to compare to other multi-FX units which DO specify their dynamic range. The problem is: if you don't know how they define it then you'll be comparing apples to oranges. Fomr what I've seen on the HD500, dynamic range is "very good".

[bjnette]

Glad you asked me to define it as that in itself can help make some measurements.

 

I would be happy with any reference, we got the guitar input;  we have the AD and the DA.(more about this later)

 

The definition would be the ratio of FS signal level to the noise floor means level. This would answer my question.

 

We can guess some areas, we have two paths which can be combined at the input stage;

If we know what the ADDA converters are we can know the dbFS. We know there is a feed off the AD thru for the S/Pdif out.

 

I am guessing 20bit converters chips were used maybe on the earlier units like the X3 and the HDs given the when the unit was released it is possible they were 24bit. Info on these would reveal much for eg I guess there could be an internal floating point at 32bit and this answers the lack of digital clipping heard when cranking the controls but may be evident when the DAC takes place.

It just may be that the Helix uses 64bit floating point in it's ADDA as well, as this type of CPU processing math =  data = resolution to re model the amps and components etc to give increased digital definition.

 

Curious I am.

If I knew what to do I'd change the ADC and DAC chips for better ones in my unit. Or tap in an existing ADDA converter if I had the specs.

I know just get a Helix. LOL

[tfreitas]

Good Morning How many devices can I register or install when you buy the model pack? I have five equipment. 02 HD500 02 HD 500x 01 POD PRO I can install in all with a single purchase?

Good Morning How many devices can I register or install when you buy the model pack? I have five equipment. 02 HD500 02 HD 500x 01 POD PRO I can install in all with a single purchase?

[Brazzy]

I'm thinking to compare to other multi-FX units which DO specify their dynamic range. The problem is: if you don't know how they define it then you'll be comparing apples to oranges. Fomr what I've seen on the HD500, dynamic range is "very good".

 

This is what I was thinking and BTW, thanks for all your info in the past years.

[bjnette]

Helix has 123db at the guitar preamp.

[pfsmith0]

Thanks bj. I wish I knew what BW they used to measure the noise floor since noise is dependent on measurement BW (whereas a sinewave is not). I recently moved and have not yet setup my DAW so it'll be a while to get anything from me. My technique, though, would be to only look at the SPDIF output to analyze the ADC/input circuitry. I don't I have the capability to accurately measure the DAC/output stages anymore as I lost access to the Audio Precision equipment. But my RME UFX ADCs "might" be good enough to measure the HD500 output. I'll have to play with that once I get my DAW setup again - maybe another month or so.

[bjnette]

My old PC thru in the towel a while ago too and not replacing till after I have move house myself.

 

I also might of answered my own question with this until making some measurements.

 

Firmware code within the confines of the processing chips used equates to the internal processing resolution followed by the ADDA converter circuits.

 

The input dynamic range is really how quiet the preamp is and how much signal it can take. (there is more to this as anyone who have good mic/Inst. Pres. knows.) 

The analogue side of the DAC is also a consideration. This is really an expansion circuit.

 

A few specs would be good.

 

Line 6 aren't the only ones not giving all the info as fair enough any manufacturer can make measurements, it is the reference or compared data that makes it useful.

 

The good thing is preamps can be made very quiet, clean and cheaply. This is what is wrong with them; lacking mojo present in quality Amps.

 

Which raises the problem of would it be too noisy to use an actual Amp input circuit albeit with some noise reducing trickery? 

 

One soon sees why the cheap clean pres get selected.

 

It would be nice to know what the specs are.