Sound is too dynamic?

Black Hole

May contain traces of nut
Think like an engineer. OK, the processor has that ability, but why would you use it? There is nothing in the spec for the HDR-FOX that says so, there is no problem that it needs to solve, and to implement some kind of audio processing would require investment of effort for no return. There would bound to be user settings (there are none), if you thought it was a good feature you would advertise it, and if you thought it was a bad idea you wouldn't do it.

Like the picture characteristics, sound control is the business of the final output - ie the TV.

I don't use multichannel, but with stereo I don't observe any unusual dynamics in the sound (we know the commercial stations up the volume of adverts). The Humax can adjust the sound stream level, which I take to be a simple scaling of the digital data. With multichannel we know the sound stream is output at a constant level, independent of the Humax volume setting. I can't vouch for whether the multichannel level has been altered in the various firmware revisions, we do know the stereo levels were adjusted between StDef and HiDef.

What about the analogue outputs? If the Humax is introducing dynamic sound processing, wouldn't the analogue sound (SCART and phono) show the same thing if stuffed into an amplifier? I run my HD-FOX into the Qumi for video and take the sound from the analogue ports.

I see no reason to point at the Humax when there is no reason to suppose it is to blame, and only one (circumstantial) report. I'm not saying it definitely isn't the case, but I am saying extraordinary claims require extraordinary evidence.
 

Ezra Pound

Well-Known Member
I do think like an engineer, unlike yourself I haven't seen the Humax Spec. but I have seen 'features' built into code that weren't supposed to be there, these features creep in of their own accord e.g. they're not designed in. Where are the user setting to control the Volume that Humax fiddled with several times? I have no gripe with the product generally but like every company they make mistakes, they have broken things in the past
 

Ezra Pound

Well-Known Member
The spec is what's published in the user guide.

If the user guide constitutes Humax's spec. for the HDR, are you really surprised it doesn't mention how they manipulate the Audio stream? There are much bigger items than that missing from it
 

Ezra Pound

Well-Known Member
Do you really suspect that it does, based on limited evidence?
Does this quote ring any bells? "Debates are a method intended to arrive at a greater truth in an adversarial forum - you have protagonists speaking for the motion and antagonists against, whether they actually believe their case or not. That is how Parliament and Courts of Law operate, and if I represent the antagonist side by playing devil's advocate there's nothing personal about it (although I admit it is sometimes seen that way) - I'm just testing the case. I might equally support the protagonist side if I think it needs it."
 

Black Hole

May contain traces of nut
Exactly, but we do usually debate based on evidence (or at least rational causality). This feels more like religion.
 

Border

Member
All boxes amplify/process the sound one way or another, I just think the output from the Humax is to dynamic.

I have a Panasonic TX-L19X5B connected to the HDR via HDMI. I too noticed this change in volume during comercial breaks. I have tried various settings on the Humax and TV but no difference.

I have only recently had HD channels (Switchover Oct 2012) but today I noticed while watching UTV-HD that pressing the PVR volume made no difference to the TV volume. Having the volume set to zero on the PVR and the TV was still full volume. I had to use adjust the Panasonics volume. I stumbled onto this thread looking for an answer.

I don't use multichannel, but with stereo...

Thanks BH - one (more) problem solved. I had my box set to multimode. (I must look up what multimode is !!). Setting the humax audio to stereo meant that now I could control volume on the HD channels via the volume on the humax. I found it strange that in multimode the Humax had absolutely no control over the volume on the TV for the HD channels but did for the ordinary channels .
 

Black Hole

May contain traces of nut
I think you mean Menu >> Settings >> Preferences >> Audio >> Digital Audio Output = Multi-channel. This means that 5.1 surround sound is sent to the TV (HDMI) or amp (SPDIF) if it is in the broadcast stream. That surround sound is at fixed volume is well known, I must add it to Things Every... (it is presumed that surround sound will be handled by an external processor, therefore the volume control is best handled by the processor).

I have a Panasonic TX-L19X5B connected to the HDR via HDMI. I too noticed this change in volume during comercial breaks. I have tried various settings on the Humax and TV but no difference.
The subject of this topic is something different. Adverts are always transmitted at a higher volume in an attempt to get your attention. If your TV has an "automatic volume" setting, it will help to level out the sound (at loss of dynamic range).

The original complaint is that there seems to be a marked difference in sound levels within the programme itself, something I see no reason to blame the Humax for, but others think differently.
 

Ezra Pound

Well-Known Member
The original complaint is that there seems to be a marked difference in sound levels within the programme itself, something I see no reason to blame the Humax for, but others think differently.

Being able to alter the dynamic audio range on the Humax would equally have benefits in curing excessive dynamic range within a single program and during the level contrasts seen between programs and advert breaks, my guess is that this could be changeable on the Humax as it is on DVD players and some TV's etc. where there is a 'Night Mode' that compresses the dynamic range of all sound output from the device. However it is very unlikely that registers that would control such a feature on the Humax SOC will ever be controllable by the Custom Firmware unfortunately
 

Border

Member
I think you mean Menu >> Settings >> Preferences >> Audio >> Digital Audio Output = Multi-channel.

The subject of this topic is something different

1 Yes I did mean multi channel not multi-mode
2 On the subject of this thread I should have wrote that I noticed the volume only during comercials. I.e. the htmax and the Panasonic tv have not the same problems AMPED describes during program play.
 
D

Deleted member 473

1) Yes, the commercials are too loud. I assume they are processed with equalized volume, and they stick out in a program with high dynamic range. That is why, whenever I watch a commercial channel, I try to record and/or chase play, so I can skip the commercials. I see no reason for the broadcaster to "flatten" the sound, and I would assume that the other sources the OP mentioned are doing precisely that, to overcome the deficiencies of their built-in speakers.

2) Yes, whether watching via the TV, Freesat or Freeview, or a DVD or Blu-Ray, it is difficult to set a volume level that allows clear dialogue and at the same time stops the wife from complaining about the sound effects being too loud. However, amplifiers can "flatten" (ie, distort) the sound if you want, and it is really up to the end user to do that. I wouldn't want us with decent equipment to suffer because others are listening through tinny speakers! :p

So, I don't think the Hummy output is too dynamic.
 

Ezra Pound

Well-Known Member
It is possible to compress the audio dynamic range without distorting the sound, as DVD players do. Purists could argue any Digital Signal Processing introduces distortion but this usually isn't detectable by the human ear
 
D

Deleted member 473

It is possible to compress the audio dynamic range without distorting the sound, as DVD players do. Purists could argue any Digital Signal Processing introduces distortion but this usually isn't detectable by the human ear

If it was done on an orchestral performance, I think I could tell.

What is your definition of "distortion?" :confused:

Edit: Ah, I see what you mean about DVDs. I think the intention though is a reversible compression that gets reversed on playback.
 

Ezra Pound

Well-Known Member
distortion has many definitions, I wasn't too sure what you meant by "flatten (ie, distort)", I regard distortion as changing a wave shape e.g. something that starts out as a sine wave should emerge as a sine wave. But the purist could argue that changing the dynamic range is a distortion of the original, DSP will also add add digital noise, I think distortion that can only be measured by instrumentation (rather than the ear) is acceptable and I wouldn't regard 'reasonable' dynamic compression as distortion
 
D

Deleted member 473

distortion has many definitions, I wasn't too sure what you meant by "flatten (ie, distort)", I regard distortion as changing a wave shape e.g. something that starts out as a sine wave should emerge as a sine wave. But the purist could argue that changing the dynamic range is a distortion of the original, DSP will also add add digital noise, I think distortion that can only be measured by instrumentation (rather than the ear) is acceptable

Pitch shift would count as sine-->sine, too.

It is not my specialist field, but amplitude compression will always introduce distortion, won't it? You can hear that in outside broadcasts where there is background noise that switches on and off as the reporter speaks. (Compression is also used to mean information compression, to add to the confusion.)

Anyway, amplitude compressed music is easily told from the pure article, at least for instrumental music.

As for the OP's point, I think the problem lies with the broadcaster. It is up to them to decide at what volume to mix dialogue in, and often they choose too low a volume, as they want exciting crashing sound effects to jolt you out of your seat. That is OKish on a TV speaker, where most of the sound is lost, but on a better system it means that when the dialogue is audible against the background noise of the living room, the effects are sometimes really loud.

So, maybe the broadcast centre channel in 5.1 is too quiet? I don't see that as Humax's problem, unless they are fiddling with it, and I hear no evidence of that, as different sources all have similar problems. Compressing the whole 5.1 signal would just make it worse!
 

Andy Hurley

Member
What about the analogue outputs? If the Humax is introducing dynamic sound processing, wouldn't the analogue sound (SCART and phono) show the same thing if stuffed into an amplifier? I run my HD-FOX into the Qumi for video and take the sound from the analogue ports.

As I said in my earlier post I am pretty sure I have observed this via the Scart output on my HDR. Playing back e.g. a typical blockbuster movie through my TV (SD connected in stereo only via the analogue scart) I get inaudible dialogue with music and FX so loud the TV rattles, I have to surf the remote pretty actively throughout. Playing back the same recording over the LAN on my laptop does not exhibit the same issue.

On programmes like this the broadcasters are presumably sending multi-channel sound - do they also send a normal stereo mix or is it down to the STB to derive one? If the latter is true then the Humax has no choice but to so some processing and how loud they make the centre channel is presumably a function of that processing. Playing back over the network would just send the original data stream so it would be down to the laptop to derive a stereo so it could well do things differently. If they are only sending a stereo stream though then this theory doesn't hold and I have no idea why they would process the sound beyond simple volume adjustment.

I will make a note of it the next time this happens and save the recording for futher analysis.
 
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