What is responsible for soundstage in a preamp design?

[Newmarket]

I don't understand saying there is no perception of depth in a single channel. That would mean a microphone would sound the same in a dead closet as it would in a concert hall. That isn't the case. Of course you can resolve timing differences that give a sense of space in mono. I thought the OP was asking about perceptible depth differences between two microphone preamps with the same input.

Yes. I was trying to nudge the discussion away from stereo concerns. But you have summarised the original point more accurately than myself. In that it relates to differences between preamps.

 

[Newmarket]

About "soundstage"? Or about perceived depth from mono sources?

JR

Neither. About the evolution of mic preamps. Obviously it's slanted toward their products being superior I should have posted as a reply to make it clearer.

 

[user 37518]

The example that comes to mind is the granular carbon mic as used in the telephone system , is it passive or active ?

Why is it wrong to express transfomer voltage gain or loss in db ?
Its obvious we cant get more power out than we put in and that bandwidth is sacrificed in the process .

No problem with expressing transformer voltage gain or loss in dB, since voltage is related to power as V^2/R, so, as long as the impedances are matched, you can definitely express transformer voltage gain in terms of dB. Ok, that is the "by the book" definition, the truth is that, even though the source and load impedances might not be matched in every case, it is very convenient to express voltage ratios in terms of dB and people do it all the time. It wouldn't technically be a dB anymore, but we still call it dB rather than the "logarithmic voltage ratio" or something similar.

As I mentioned in my previous post, the granular carbon mic can be considered active or passive depending on the definition of passivity you use. If you use the "incrementally passive" definition, it could be considered active, since you can control current flow and you can get a power gain output.

 

[ccaudle]

Its not all about the preamp , mic and micing technique play a big role also

Of course, but mic technique is not related to the original question. See post #1

 

[Tubetec]

To be honest I dont like applying this term '3D' in relation to single source mono , its missleading ,
I think quite a few of us have now agreed depth is a far better description ,
this idea of mono depth applies just the same with two mono sources panned L/R so stereo applications are equally relevent in the discussion as far as I can see .

Why is there a need to limit the scope of the discussion CC ?
theres plenty of relevent and coherent points being made by smart people ,
you cant really box in the convo either way ,

 

[ccaudle]

theres plenty of relevent and coherent points being made

There are plenty of tangential and coherent points being made, I have not seen much which is directly relevant to the original question (at least as phrased).

 

[Gold]

There are plenty of tangential and coherent points being made, I have not seen much which is directly relevant to the original question (at least as phrased).

I am assuming that the more 3D preamp is preserving the spacial cues that are already present in the signal. Now if the more 3Dness happens with a DI input I’ll admit my explanation may not apply/

 

[ccaudle]

I am assuming that the more 3D preamp is preserving the spacial cues that are already present in the signal.

I am assuming that the more 3D preamp is generating euphonic distortion that the OP's brain interprets as indicating depth.
How would we determine which assumption is correct?

 

[Newmarket]

I am assuming that the more 3D preamp is generating euphonic distortion that the OP's brain interprets as indicating depth.
How would we determine which assumption is correct?

Well wrt distortion - could measure THD and IMD quite easily. And via FFT analysis. Although IMD frequencies and FFT parameters need consideration. I am thinking of measurement to AP2 or Prism Audio standards so obvs not available to everyone.

 

[Gold]

I am assuming that the more 3D preamp is generating euphonic distortion that the OP's brain interprets as indicating depth.
How would we determine which assumption is correct?

My assumption could be answered by the OP. If the answer is that the DI doesn't sound more 3D than a microphone, then I'd look for masking of spacial cues present in the input signal. More likely noise than distortion. If the answer is that the DI does sound more 3D through one preamp I would look first at distortion.

First you would have to measure for distortion. Then you would have to try to increase and decrease the amount of distortion on a level matched signal and see if that produces more, less or no difference in 3Dness.

 

[Tubetec]

A DI sounds like hole in the head mono to me ,no matter what you do with it ,
the under bridge piezo is full on in your face ,
dryer than the nuns proverbials , it has no dimesionality .

a mic gives some variation in tone depending on the movements of the performer , that in itself gives a sound depth, in a stereo context its equally applicable and the pan pot allows you apply width , the talented artist also uses distance from the mic to balance out to dynamics ,

Lets not get not so hung up on semantics for the sake of it killing the spirit of the post ,
If I relabeled the pan pot on my mixer crosstalk is there any point arguing ?

 

[Gold]

A DI sounds like hole in the head mono to me ,no matter what you do with it ,
the under bridge piezo is full on in your face ,
dryer than the nuns proverbials , it has no dimesionality .

a mic gives some variation in tone depending on the movements of the performer , that in itself gives a sound depth, in a stereo context its equally applicable and the pan pot allows you apply width , the talented artist also uses distance from the mic to balance out to dynamics ,

Lets not get not so hung up on semantics for the sake of it killing the spirit of the post ,
If I relabeled the pan pot on my mixer crosstalk is there any point arguing ?

I’m not sure how a pan pot has anything to do with anything in this thread. It moves things side to side in stereo. It doesn’t add depth or 3Dness. To get depth in multichannel stereo you need other things like reverb or hass effect.

I was wondering what the OP thought of a DI input. If the quality in question doesn’t apply to a DI input then I’d look at masking of the microphone spacial cues. If it does apply to the DI I’d look at preamp distortion mechanisms.

 

[Tubetec]

Micing things up in a room doesnt give nearly as good specs as the Shakur Paul DI mixtable ,

Yes panned mono gives only level difference ,but in conjunction with ambient mics it can form a wide stereo image ,

Can you perceive 3D sound in an anechoic chamber from a single sound source?

 

[Diamondj421]

During the pandemic, I had to sell off some gear to make ends meet so I was shooting out some preamps that I had built vs their UAD plug-in counterparts to see if they were really worth holding onto. I had 2 friends with me and when we A/Bed a mono bass DI, we all agreed that the hardware sounded more “3-dimensional” than the plugins. So in this case, mic positioning, room reflections, etc weren’t in the equation. I’ve been wondering what the difference is ever since.

 

[JohnRoberts]

I've shared this strategy before but null testing can be used to compare two similar SKU. It will only tell you if they are different not which one is accurate.

JR

 

[Silveradodays]

This, despite some tangential deviations from the original topic, has been a really cool and informative discussion.

In my opinion mono gear that gives a better sense of "realness" and "depth" is usually related to a couple factors, one is having a bump or slight resonance in the very lows and highs, and it's usually associated with the input xformer. The other is having a distorsion spectral profile than leans more to the lows that the highs.

And I think that's why the term is usually associated with tube preamps and gear.

 

[gyraf]

What if we are dealing with some chaotic element here?

As I see it, these claims of 3dness and just-betterness seem to be attached to 1) transformer balanced gear that is 2) not very-low distortion designs. This could point towards something chaotic going on - an inductor and a nonlinearity is more or less all it takes to build truely chaotic systems, i.e. systems whos resulting states are so dependent on minute variations of initial conditions that there exist no way to predict these (although it's still a deterministic system, off course). Maybe we - our auditory systems - just like our sound served with a wee bit of chaotic sauce..?

Or am I too far out here?

/Jakob E.
ref, e.g.: https://physlab.org/wp-content/uploads/2016/04/ChaosRLD_Fatima_July2019v1-compressed.pdf

 

[Ricardus]

I don't mean to be the nay-sayer, but what if it simply wasn't real? Human perception sucks. Maybe he's chasing my sweet corn analogy (from a post I made last week)?

I read a lot of online reviews of home ho-fi equipment, mostly to read their silly descriptions which are ALWAYS entertaining, and I have seen two different reviewers on two different sites review the same piece of gear with opposite adjectives.

I was in the market for some converters last month and all of my friends, and the online reviews all recommended something different because the one they liked sounded "3D" and the others didn't.

I think whether or not you had lunch, and the mood you woke up in will have more impact on subjective listening results, than the actual sounds you're hearing.

 

[Silveradodays]

That's true, confirmation bias is incredibly powerful in our brains. Even when trying to avoid it at all costs, it's really hard to overcome it when you are just trying stuff in your studio.

That being said when I'm looking for a more focused sound or a more "real" sound it's the mic what I'm swapping and tend no to think about the preamp as having much effect on that.

 

[JohnRoberts]

I don't mean to be the nay-sayer, but what if it simply wasn't real? Human perception sucks. Maybe he's chasing my sweet corn analogy (from a post I made last week)?

I read a lot of online reviews of home ho-fi equipment, mostly to read their silly descriptions which are ALWAYS entertaining, and I have seen two different reviewers on two different sites review the same piece of gear with opposite adjectives.

I was in the market for some converters last month and all of my friends, and the online reviews all recommended something different because the one they liked sounded "3D" and the others didn't.

I think whether or not you had lunch, and the mood you woke up in will have more impact on subjective listening results, than the actual sounds you're hearing.

I escaped the hifi market back in the 80s after receiving night and day different (good/bad) reviews for the exact same phono preamp from two different reviewers. Giving them the benefit of a doubt, the reviewers were probably hearing the differences in their personal playback systems. Phono cartridges, loudspeakers, and listening room acoustics surely vary orders of magnitude more than my preamp did.

JR

PS: Just like the phono cartridges (and loading) introduced a huge variable in phono preamp response, the microphones are a far weaker link than most mic preamps.