The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Gordon vs. Pueblo (vs. Forssell, Pendulum, NPNG, Audio Upgrades...)
Old 23rd September 2013
  #31
mpr
Lives for gear
 
mpr's Avatar
 

I have also discovered what SoSueMe said regarding multing mic signals between two preamps. The sound changes compared to a direct connection, and it usually affects one pre more so than the other. I agree that it must be an impedance issues that affects the high end in particular.

Rumi, I am very sorry to hear about your burglary, where 21 mics were stolen. That is my worst nightmare. I am glad to see you rebounding so well and that your engineering spirit is obviously still intact.

My suggested test (to be done in addition to the others) is to use your 3 CAD 350s as best you can. First confirm that their frequency responses are as close as possible using the same pre on each each mic, but across 3 performances. Then after confirming that the 3 CADs are 'matched' close enough for testing purposes, line up all three capsules as close as possible (pick an axis for all of them to share according to the instruments dispersion) and record a single instrument performance (solo acoustic guitar would be nice) with three different pres (and three 350s). You could even swap the pres and mics around for a second or third take to ensure the positioning and mic differences arent throwing off the test. Again, this would be just one test along the road...

Your list of pres is the most impressive gathering I have ever seen on GS or in any studio. Looking forward to your results. Don't forget to have fun!
Old 23rd September 2013
  #32
Lives for gear
 
jupiter8's Avatar
 

Just out of curiosity since it's mentioned in the thread topic: is Audio Upgrades in the same league as the other pres mentioned here ?
Old 23rd September 2013
  #33
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by SoSueMe View Post
Oh, and running the mics through a passive splitter like the Radial is a total fail. This is because it is not true isolation and one preamp will influence the other, and I can prove this.

One way to observe this phenomenon is to compare two preamps, one of which has controls that can change the impedance or switch transformers on the fly. When making these changes, listen to the sound of the other preamp and you'll notice the sound of it will change. I've done this test many times with the APA Juggernaut Twin.
Yeah, I had the impression that this will be the case, although I've never tested it. The naive image of a signal flowing through an amplifier from input to output is simply incorrect. It's more like circles that act as loads for each other (to put it in very layman's terms).

I won't use the splitter!

I intend to include at least some stereo recordings in the test, and maybe add some mono sources.
Old 23rd September 2013
  #34
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by SoSueMe View Post
@Rumi,

Some people here feel that mono comparisons aren't representative enough. Personally I think they are fine.

Just remember to swap the preamps and do an additional recording for each pair! Why? Because the two mics will in fact sound different no matter how you place them. In other words, you may favor the position of one over the other, or even the frequency response of the other. Swapping and recording both versions alleviates this.

If you want to go all out, I can level match everything for you, and turn it into a low bias scientific test and then repost the files with an encrypted key.
Good points, thank you!
I really hope I find the time for all this!

Thank you for your offer for double-blind tests!
Old 23rd September 2013
  #35
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by fifthcircle View Post
SoSueMe- you're absolutely correct.

This is why I didn't ever post any of the tests I did when I was first trying the Pueblos. I did a shootout during a sound check between them and my Forssell pres. However, to make sure they were behaving to their absolute highest quality, I plugged the mics directly into each pre. However, that also meant that I wasn't always recording the exact same music/performance/etc... Didn't feel like dealing with the GS "experts" that didn't listen to the test and just want to poke holes in the method.

And Rumi- glad that you're finally going to get a way to listen to the Pueblos. I think you're going to be happy with them.

--Ben
Yes, I'm looking forward! Thank you very much for your encouragement (in the form of very positive reviews) for my going ahead with ordering them. As far as I recall you were the first who gave me more data about the Pueblos.
Old 23rd September 2013
  #36
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by fifthcircle View Post
SoSueMe- you're absolutely correct.

This is why I didn't ever post any of the tests I did when I was first trying the Pueblos. I did a shootout during a sound check between them and my Forssell pres. However, to make sure they were behaving to their absolute highest quality, I plugged the mics directly into each pre. However, that also meant that I wasn't always recording the exact same music/performance/etc... Didn't feel like dealing with the GS "experts" that didn't listen to the test and just want to poke holes in the method.

And Rumi- glad that you're finally going to get a way to listen to the Pueblos. I think you're going to be happy with them.

--Ben

And yes, let me state that clearly here: I will hopefully find the time to record some comparisons, and I will likely post them here. I will be careful and thorough, but I certainly won't be able to fulfil all expectations.

If you think my tests are flawed, please go and read a different thread, or jump up and down until you feel calm and neutral. Don't post here. Unless you contribute with constructive input on how to improve the tests to have a more meaningful outcome.

If I post my files, it is meant as a contribution. Everyone is free to take out of them what feels appropriate for you. If there is nothing in it for you, so be it.

Don't take it as the truth. Make your own tests! And most of all, record some great music. That's what it's all about.

Okay, it's said.

Old 23rd September 2013
  #37
mpr
Lives for gear
 
mpr's Avatar
 

Well, stereo tests do seem to drive home the differences even more so than mono, but mono is easier to manage. I dont know why this is, but I am sure it is partly psycho-acoustic in nature.

If you have a jecklin disk with some omnis... now we are talking. Headphones on and prepare to be amazed at the spatial differences between the pres.

heh I am not kidding here. Try it!
Old 23rd September 2013
  #38
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by mpr3 View Post
I have also discovered what SoSueMe said regarding multing mic signals between two preamps. The sound changes compared to a direct connection, and it usually affects one pre more so than the other. I agree that it must be an impedance issues that affects the high end in particular.
As far as I understand the impedance mismatch happens when you simply split the signal, for example with the help of a half-normalled patchbay. The impedance is then divided by the number of receiving devices. Each device might react differently to an impedance that is too low (for example, when people complain about "the frequency anomalies of the ADL 1500 compressor", they feed it with an inappropriate impedance. The mid frequencies then sag the more the unit compresses. With proper impedance matching it is a wonderful unit, and shows none of that behavior). What you will find out in such a test is how the unit reacts to impedance mismatch, and not how it sounds.

When you use splitters with transformers you isolate the circuits. The mic and the primary coil of the transformer form a closed circuit together, and each unit forms a closed circuit with their corresponding secondary coil. What the inputs of the units "see" then is the impedance of the secondary coil. So there is no impedance mismatch.
Still, they represent loads to each other (or whatever the correct word is - they are electromagnetically coupled), and that can affect their sound. And furthermore the transformer will add its sound.

I hope this is understandable - English is not my main language. And it might all be incorrect anyway. I hope someone with real knowledge in electricity will correct me if I'm wrong, or add data.

When someone explained to me that an amplifier doesn't amplify a signal, but makes a (more or less exact) copy of it with higher amplitude, I had the impression that I understand a little more about it all. There is no signal flowing through a unit. It's more like closed circuits that interact and affect each other.

Quote:
Originally Posted by mpr3 View Post
Rumi, I am very sorry to hear about your burglary, where 21 mics were stolen. That is my worst nightmare. I am glad to see you rebounding so well and that your engineering spirit is obviously still intact.
Thank you very much!
It was an intense time, with a lot of changes. The mics were so easily accessible because I had stacked them all to test them, to see which ones I will keep. I sold about 2/3 of my studio equipment during that time, and went on long retreats.
Some of the mics stolen were one of a kind.
Thank God they didn't take the Wagner, and also some other mics.
That burglary was part of a much bigger transition, and the outcome of that transition is very wonderful. I also experienced so much support from the audio community! It was heart-warming.
I moved into a new studio in March, and it's thriving! I enjoy working with sound very much.

Quote:
Originally Posted by mpr3 View Post
My suggested test (to be done in addition to the others) is to use your 3 CAD 350s as best you can. First confirm that their frequency responses are as close as possible using the same pre on each each mic, but across 3 performances. Then after confirming that the 3 CADs are 'matched' close enough for testing purposes, line up all three capsules as close as possible (pick an axis for all of them to share according to the instruments dispersion) and record a single instrument performance (solo acoustic guitar would be nice) with three different pres (and three 350s). You could even swap the pres and mics around for a second or third take to ensure the positioning and mic differences arent throwing off the test. Again, this would be just one test along the road...
Yes, I will do it that way. And I am a professional guitarist, so there will definitely be some guitar.

May I ask why you suggest the CADs, and not the Grosser-modified Gefells? The CADs are big, it might be hard to get them close enough to each other. Apart from that, they are great mics. Since I suggested them to so many people, I could organize at least six of them. But that would make quite an array, far from coincidence recording.
I will send the Gefells to Andreas Grosser this week. I bought them from someone else, but Andreas told me that I have to send them to him, and he will upgrade them for free, because he has found a better FET for them since. Andreas is such a nice being! Very commited to his work. And I will look for more Thiersch'd M70.

Quote:
Originally Posted by mpr3 View Post
Your list of pres is the most impressive gathering I have ever seen on GS or in any studio. Looking forward to your results. Don't forget to have fun!
Thank you, I wasn't aware of that! They have just come together over time...
But when I listened to the Lynn Fuston preamps DVD I realized that most of the ones I liked I own. There's still the Gordon, though... And I also liked Great River and Lipinski in that test.

And yes, I won't forget to have fun!

Thank you for your kind words.
Old 23rd September 2013
  #39
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by mpr3 View Post
Well, stereo tests do seem to drive home the differences even more so than mono, but mono is easier to manage. I dont know why this is, but I am sure it is partly psycho-acoustic in nature.

If you have a jecklin disk with some omnis... now we are talking. Headphones on and prepare to be amazed at the spatial differences between the pres.

heh I am not kidding here. Try it!
Would a Jecklin disc with two DPA 4061 work? Or I could use the Gefell MK221, or even M582 with M52?

But it wouldn't be possible to have more than one preamp at a time with a Jecklin disc. Hmmm.
Several tests??
Old 23rd September 2013
  #40
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by jupiter8 View Post
Just out of curiosity since it's mentioned in the thread topic: is Audio Upgrades in the same league as the other pres mentioned here ?
I asked Mike Jasper (who reviewed both in TapeOp) about Gordon vs. Audio Upgrades, and his reply was

"Get the Gordon. The Audio Upgrades is cheaper and works well, but the low end on the Gordon is amazing. It sounds clear, accurate, but never sterile.

I also owned a Millennia, and it killed that too. I still prefer an old Neve on vocals, but for pure acoustic guitar you can't beat the Gordon."

From what I've heard Gordon and Pueblo (and for some also Forssell and NPNG) seem to be in a league of their own. But there will always be people who prefer another of those high-end pres (GML, Martech, Hardy, Crane Song, Grace, Millennia, Audio Upgrades, Pendulum, etc.).

What I've read is that some people prefer the Audio Upgrades pre over the DACS Clarity ("more fluid" was one statement, if I remember correctly). Unfortunately I have never heard the Audio Upgrade pre. There were some units on ebay recently for great prices.
Old 24th September 2013
  #41
Gear maniac
 

Quote:
Originally Posted by Rumi View Post
I would like to do my tests with two identical stereo mics, and two preamps at a time...


I just wanted to chime in here, and say that your plans are awesome -- and most generous to share with the rest of us here on GS! I'm eagerly awaiting anything you are able to post!
Old 24th September 2013
  #42
Lives for gear
Quote:
Originally Posted by fifthcircle View Post
SoSueMe- you're absolutely correct.

This is why I didn't ever post any of the tests I did when I was first trying the Pueblos. I did a shootout during a sound check between them and my Forssell pres. However, to make sure they were behaving to their absolute highest quality, I plugged the mics directly into each pre. However, that also meant that I wasn't always recording the exact same music/performance/etc... Didn't feel like dealing with the GS "experts" that didn't listen to the test and just want to poke holes in the method.
--Ben
I'm not answering your post directly, but rather just making some general points based on what you said...

Let's say you have two mono preamps and two 'matched' mics (no two mics are never truly matched, by the way, and you can absolutely pick one out over the other in a thorough scientific comparison).

You place the mics close to each other (about 1/2 inch or 1.25 cm to avoid shadowing - don't get closer than that). Each mic goes into its own preamp. Even if the preamps were identical, you *will* hear a difference between the two files in a thorough scientific test. Since microphones and their positioning arguably have a more profound effect on the signal than a mic preamp, generally speaking, this effect will overshadow any minute differences in *most* NON-identical preamps. Who is going to argue that most preamps have a more profound effect than the mic, its position, and its surrounding environment?

So what does this mean? It means that the test above is scientifically irrelevant, and people perform tests like these on gearslutz all the time. The only reason I'm making this post is to help out and bring comparisons up to a level that are actually scientifically relevant (don't be afraid; this is a good thing). If anyone's interested, I'll help you do this. If you want to see what a real scientific comparison looks like on a forum, look here.

Yes, there is the argument of real-world experience in the room with the mics and the preamps. But, most of us do not have that luxury. I personally believe it is possible to get way more out of file comparisons than what is typically posted on these boards.

So, how do we differentiate/remove the mics from the equation in the above test so that we take the next step in coming up with a meaningful comparison? We record at least one more performance, but NOT before we switch the preamps. We also keep a record of this (very important). If the files are properly executed, the mics can essentially be "nulled out" so that their unique characteristics do not contribute to what we're really trying to compare here: The preamps.

Once the two files (at minimum) are recorded, they can now be cut up, sliced, randomized, and level-matched so that they can be implemented into a test that will give back meaningful results, not a bunch of placebo that doesn't do anybody any good. Again, I can do this last part.

Also, the same thing can be performed with two stereo preamps and four 'matched' mics.

And Rumi, I won't scrutinize anything you post on here. I'm just offering help if anyone wants it. At any rate, I'll probably eventually pick up the Pueblo and do a comparison between it and my SMP-2A (Forssell).
Old 24th September 2013
  #43
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by SoSueMe View Post
I'm not answering your post directly, but rather just making some general points based on what you said...

Let's say you have two mono preamps and two 'matched' mics (no two mics are never truly matched, by the way, and you can absolutely pick one out over the other in a thorough scientific comparison).

You place the mics close to each other (about 1/2 inch or 1.25 cm to avoid shadowing - don't get closer than that). Each mic goes into its own preamp. Even if the preamps were identical, you *will* hear a difference between the two files in a thorough scientific test. Since microphones and their positioning arguably have a more profound effect on the signal than a mic preamp, generally speaking, this effect will overshadow any minute differences in *most* NON-identical preamps. Who is going to argue that most preamps have a more profound effect than the mic, its position, and its surrounding environment?

So what does this mean? It means that the test above is scientifically irrelevant, and people perform tests like these on gearslutz all the time. The only reason I'm making this post is to help out and bring comparisons up to a level that are actually scientifically relevant (don't be afraid; this is a good thing). If anyone's interested, I'll help you do this. If you want to see what a real scientific comparison looks like on a forum, look here.

Yes, there is the argument of real-world experience in the room with the mics and the preamps. But, most of us do not have that luxury. I personally believe it is possible to get way more out of file comparisons than what is typically posted on these boards.

So, how do we differentiate/remove the mics from the equation in the above test so that we take the next step in coming up with a meaningful comparison? We record at least one more performance, but NOT before we switch the preamps. We also keep a record of this (very important). If the files are properly executed, the mics can essentially be "nulled out" so that their unique characteristics do not contribute to what we're really trying to compare here: The preamps.

Once the two files (at minimum) are recorded, they can now be cut up, sliced, randomized, and level-matched so that they can be implemented into a test that will give back meaningful results, not a bunch of placebo that doesn't do anybody any good. Again, I can do this last part.

Also, the same thing can be performed with two stereo preamps and four 'matched' mics.

And Rumi, I won't scrutinize anything you post on here. I'm just offering help if anyone wants it. At any rate, I'll probably eventually pick up the Pueblo and do a comparison between it and my SMP-2A (Forssell).
Hi!

Your points are very valuable, and thank you for posting them!
Some years ago I did many comparison tests, but after that test with the CD de-magnetizer, where it turned out in the end that we were comparing bit-identical files (and two participants still could hear the difference!), I stopped doing comparisons. (Interestingly enough a physics professor bought that CD de-magnetizer when I put it on ebay after those tests. I would have loved to hear why he does that, since he must know that there is nothing magnetizable in a CD.)

I still wonder how people can hear the power cord of their amplifiers - a few feet of lenght, after miles of cable coming from the power plant. And you have to turn the amp down, switch cables, turn the amp on again, and then say "Ah yes, now the lows are in place again, the highs are much less strident, and the mids are just so smooth - this is why I spent $500 for that cable!" Even if there actually is a difference between the "tone" of power cables, you are not able to tell it with such a test.

I thankfully accept your offer to help in these tests!

And yes, the first time I read your first post, it was "Oh well, let's see where this thread is going now", but you've proven that you are a very valuable contributor. Thank you!

I will do the Nebula vs. hardware test in the link you've posted. I like Nebula a lot.
Old 24th September 2013
  #44
Lives for gear
 
Rumi's Avatar
 

Thread Starter
What would be the best way to calibrate the units? Would two files of the identical take be enough? Or 1kHz sine wave at the beginning, coming from a loudspeaker that sits where the instrument will be? Or pink noise?
Old 24th September 2013
  #45
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by bcfromfl View Post


I just wanted to chime in here, and say that your plans are awesome -- and most generous to share with the rest of us here on GS! I'm eagerly awaiting anything you are able to post!
Thank you!
Old 24th September 2013
  #46
Lives for gear
Quote:
Originally Posted by Rumi View Post
Hi!

Your points are very valuable, and thank you for posting them!
Some years ago I did many comparison tests, but after that test with the CD de-magnetizer, where it turned out in the end that we were comparing bit-identical files (and two participants still could hear the difference!), I stopped doing comparisons. (Interestingly enough a physics professor bought that CD de-magnetizer when I put it on ebay after those tests. I would have loved to hear why he does that, since he must know that there is nothing magnetizable in a CD.)
I remember that product! Pure snake oil. That and those tiny little discs the size of large coins you strategically place on your walls for dramatic acoustic alteration.

The two that heard a difference only thought they heard the difference. I'm sure you know this, but that is a common theme a lot of people cannot relate to. Just because a person thinks he/she can hear a difference doesn't mean there is a difference. You would be surprised how many people do not understand that concept. We're only human.

When we get to a certain point of very fine details/differences between two audio files, for example, even though a scope can easily pick this up, it doesn't mean our ears/brain can. Furthermore, this is where the brain will inevitably inject "placebo," and you *will* begin to hear things that are not there. Because of this, we [scientists] developed a way to determine whether or not we are actually hearing a real difference, or whether or not we are just guessing. And we can do this with very high confidence.

The problem with posting non-scientific tests is that they can easily favor the 'inferior' product. So, while the poster has good intentions, the opposite effect can result. A good example is comparing two identical files, but one of them has an overall RMS figure of 0.5 dB higher than the other. Not only will the subjects continually pick the hotter file, they will almost always remark on how different the file sounds using various terms like "beefier," when in fact, it's the same file.

The above is a simple concept. But, what a lot of people don't understand (including many audio professionals) is that a difference of 0.5 dB (or even less) can MASK a product's attributes that would otherwise be favorable to it. Instead, they can easily be mislead by the hotter file, making the "better" product seem inferior.

The 0.5 dB example is just one of many flaws in typical comparisons you see on boards like this. There are many other things that can easily flaw a comparison, rendering it to the opposite effect of its real intention.

I believe people poke holes in a lot of tests not to be mean, but rather out of frustration (I'm no exception). That said, some tests on here do have value, but many can actually become much more relevant and useful by doing a couple of extra things (the mic/preamp swapping, for example).

Quote:
Originally Posted by Rumi View Post
I still wonder how people can hear the power cord of their amplifiers - a few feet of lenght, after miles of cable coming from the power plant. And you have to turn the amp down, switch cables, turn the amp on again, and then say "Ah yes, now the lows are in place again, the highs are much less strident, and the mids are just so smooth - this is why I spent $500 for that cable!" Even if there actually is a difference between the "tone" of power cables, you are not able to tell it with such a test.
Again, they only think they can. But, if it makes them feel better sometimes there's something to be said for the old saying, "ignorance is bliss". If too many pieces of equipment were shown to sound identical in scientific tests, then it would squash our desires to salivate over the latest and greatest, and that's no fun!

Quote:
Originally Posted by Rumi View Post
I will do the Nebula vs. hardware test in the link you've posted. I like Nebula a lot.
Great! Please try not to look at the other answers, as that can skew the results. The test isn't perfect, but later I plan on using the files in my comparison application, which is MUCH easier, faster, and with much more relevant results.

Some files posted on gearslutz may qualify to be used with the application. They have to follow certain guidelines so that they do not contribute to any flaws in the outcome. Other files may qualify with some post-production. In the case of your files, as long as you swap the preamps, they will likely qualify with a little post-production (level matching, for example). The beta version will not be available for a while, but eventually there will be tools to do this kind of thing automatically. I'm not developing the app with the intention to make a profit, but rather to contribute to science by taking aural comparisons to another level beyond what is available, and to aid in psychoacoustic research. It's basically a highly advanced, nearly non-existent bias file comparison solution that goes way beyond other ABX tools out there. If you want to really know what you're hearing, or what you think you're hearing, this is it.

In the meantime, posting your files on here can still be very valuable, and I'm looking forward to them!
Old 24th September 2013
  #47
Lives for gear
Quote:
Originally Posted by Rumi View Post
What would be the best way to calibrate the units? Would two files of the identical take be enough? Or 1kHz sine wave at the beginning, coming from a loudspeaker that sits where the instrument will be? Or pink noise?
Pink noise is fine, but it doesn't have to be perfect as you're not matching the levels perfectly anyways between preamps in a typical multi-track scenario, for example. Know what I mean? You could even just eye the levels in your DAW while you're playing to make sure the levels are fairly close between the preamps, as this is more real world. Pink noise/calibration is not required.
Old 24th September 2013
  #48
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by SoSueMe View Post
I remember that product! Pure snake oil. That and those tiny little discs the size of large coins you strategically place on your walls for dramatic acoustic alteration.
Ah, yes. Funny, the vendor had these with him, too. And I could hear a difference! In the end I bought a Pass Labs X-250 from him, and I still use that. And yes, I can hear a difference.

Quote:
Originally Posted by SoSueMe View Post
"ignorance is bliss"
Ha! I have never heard that saying, and this is definitely not my experience. But maybe it makes some ignorant people feel a little better. I would still recommend the real thing.

I agree with what you're saying, and your test procedure sounds very interesting! The 0,5 dB thing (I would even go as low as 0,1 dB) can not be underrated.
Old 24th September 2013
  #49
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by SoSueMe View Post
Pink noise is fine, but it doesn't have to be perfect as you're not matching the levels perfectly anyways between preamps in a typical multi-track scenario, for example. Know what I mean? You could even just eye the levels in your DAW while you're playing to make sure the levels are fairly close between the preamps, as this is more real world. Pink noise/calibration is not required.
The question was about how to make it possible to level match them for playback. Since slew rate, frequency response etc. have an effect, peak matching or even adjusting phase-reversed files for minimal low frequencies might be not close enough.

Maybe taking the same peak level for pink noise over 20 seconds or so will do? Or white noise?

The other point is "sweet spots". The API for example is said to sound different with different gain. But if you go into that, you will possibly end up with too many variables to compare. I don't plan to spend the rest of my life comparing mic pres.
Old 24th September 2013
  #50
Lives for gear
Quote:
Originally Posted by Rumi View Post
The question was about how to make it possible to level match them for playback. Since slew rate, frequency response etc. have an effect, peak matching or even adjusting phase-reversed files for minimal low frequencies might be not close enough.

Maybe taking the same peak level for pink noise over 20 seconds or so will do? Or white noise?

The other point is "sweet spots". The API for example is said to sound different with different gain. But if you go into that, you will possibly end up with too many variables to compare. I don't plan to spend the rest of my life comparing mic pres.
Oh, I misunderstood. I usually do RMS matching over short intervals of the actual program material (musical content). Pink noise is pretty much static, so it's not going to be representative of dynamic content. Preamps and other equipment react differently to changes in level, and pink/white noise is not going 'challenge' the preamps in this way.

As far as sweet spots, IMO, I would adjust the preamp as you would in real life to take the best advantage of it, then RMS match in post. This will take advantage of each preamps' best attributes since post production techniques like this have much less interaction on the signal by comparison.
Old 24th September 2013
  #51
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by SoSueMe View Post
Oh, I misunderstood. I usually do RMS matching over short intervals of the actual program material (musical content). Pink noise is pretty much static, so it's not going to be representative of dynamic content. Preamps and other equipment react differently to changes in level, and pink/white noise is not going 'challenge' the preamps in this way.

As far as sweet spots, IMO, I would adjust the preamp as you would in real life to take the best advantage of it, then RMS match in post. This will take advantage of each preamps' best attributes since post production techniques like this have much less interaction on the signal by comparison.
Interesting points, thank you!
And they even make my testing easier... Hoorray!
Old 24th September 2013
  #52
mpr
Lives for gear
 
mpr's Avatar
 

Wow you guys have been busy. I don't even know where to begin.

Rumi, I mentioned the CADs because you said you have three of them and they are known to be very consistent, much more so than vintage Gefells (or vintage anything for that matter). I do realize that getting those large caps close enough is going to be a challenge, but give it a shot! And then, if you have three of the same Gefell caps, give that a go, but realize that the cap deltas could be large enough to throw off their 'constant' in this experiment.

As far as testing is concerned, there is no need to over think this. Many of us have been A/Bing or A/B/Cing mics and pres for decades and know how to avoid skewed results:

1) Multiple takes after swapping the mics across the preamps, even if they are identical and capsule aligned.

2) Label the mics 1,2,3,4,etc and label the pres A,B,C,D,E,etc with little stickies, and then name your files accordingly: A1 or B1 or B3 or C4 etc. Avoid naming the files with pre names. This will help you keep a gap between the manufacturer and your expectations.

3) Keep listening tests blind by either bringing in a second person to help switch during listening, or devising a way to randomly play without you looking at the playback file: B3

4) In addition to the different takes involved in the methods already outlined in this thread, also do different 'rounds of takes' where the gains are 5db up or down across all pres. You can label this into the files as: A1-5 or A1+5, along with your nominal A1.

5) And for the freaks among us, try to use similar mic and power cables.

Thats it! Again, acoustic guitar is awesome for this, especially since you can exploit the boominess in relation to the high end transients. It doesnt have to be a record friendly recording, just one that delivers solid information for the listeners to discern differences.

Have fun!
Old 24th September 2013
  #53
Lives for gear
Quote:
Originally Posted by mpr3 View Post
Wow you guys have been busy. I don't even know where to begin.

Rumi, I mentioned the CADs because you said you have three of them and they are known to be very consistent, much more so than vintage Gefells (or vintage anything for that matter). I do realize that getting those large caps close enough is going to be a challenge, but give it a shot! And then, if you have three of the same Gefell caps, give that a go, but realize that the cap deltas could be large enough to throw off their 'constant' in this experiment.

As far as testing is concerned, there is no need to over think this. Many of us have been A/Bing or A/B/Cing mics and pres for decades and know how to avoid skewed results:

1) Multiple takes after swapping the mics across the preamps, even if they are identical and capsule aligned.

2) Label the mics 1,2,3,4,etc and label the pres A,B,C,D,E,etc with little stickies, and then name your files accordingly: A1 or B1 or B3 or C4 etc. Avoid naming the files with pre names. This will help you keep a gap between the manufacturer and your expectations.

3) Keep listening tests blind by either bringing in a second person to help switch during listening, or devising a way to randomly play without you looking at the playback file: B3

4) In addition to the different takes involved in the methods already outlined in this thread, also do different 'rounds of takes' where the gains are 5db up or down across all pres. You can label this into the files as: A1-5 or A1+5, along with your nominal A1.

5) And for the freaks among us, try to use similar mic and power cables.

Thats it! Again, acoustic guitar is awesome for this, especially since you can exploit the boominess in relation to the high end transients. It doesnt have to be a record friendly recording, just one that delivers solid information for the listeners to discern differences.

Have fun!
You forgot one of the most important parts: Level matching. And, there is a lot you don't mention that may completely flaw the results as well, but we're off topic and I'm not going to get into it. Carry on....
Old 24th September 2013
  #54
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by SoSueMe View Post
You forgot one of the most important parts: Level matching. And, there is a lot you don't mention that may completely flaw the results as well, but we're off topic and I'm not going to get into it. Carry on....
I would like to know!
I am not into spending time for flawed tests.
Old 24th September 2013
  #55
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by mpr3 View Post
Wow you guys have been busy. I don't even know where to begin.

Rumi, I mentioned the CADs because you said you have three of them and they are known to be very consistent, much more so than vintage Gefells (or vintage anything for that matter). I do realize that getting those large caps close enough is going to be a challenge, but give it a shot! And then, if you have three of the same Gefell caps, give that a go, but realize that the cap deltas could be large enough to throw off their 'constant' in this experiment.

As far as testing is concerned, there is no need to over think this. Many of us have been A/Bing or A/B/Cing mics and pres for decades and know how to avoid skewed results:

1) Multiple takes after swapping the mics across the preamps, even if they are identical and capsule aligned.

2) Label the mics 1,2,3,4,etc and label the pres A,B,C,D,E,etc with little stickies, and then name your files accordingly: A1 or B1 or B3 or C4 etc. Avoid naming the files with pre names. This will help you keep a gap between the manufacturer and your expectations.

3) Keep listening tests blind by either bringing in a second person to help switch during listening, or devising a way to randomly play without you looking at the playback file: B3

4) In addition to the different takes involved in the methods already outlined in this thread, also do different 'rounds of takes' where the gains are 5db up or down across all pres. You can label this into the files as: A1-5 or A1+5, along with your nominal A1.

5) And for the freaks among us, try to use similar mic and power cables.

Thats it! Again, acoustic guitar is awesome for this, especially since you can exploit the boominess in relation to the high end transients. It doesnt have to be a record friendly recording, just one that delivers solid information for the listeners to discern differences.

Have fun!
Thank you! I will do the labeling that way.

The Gefells will be modded and newly checked by Andreas Grosser, and the capsules will be refurbished by Thiersch.
Old 24th September 2013
  #56
Lives for gear
 

Quote:
Originally Posted by SoSueMe View Post
You forgot one of the most important parts: Level matching. And, there is a lot you don't mention that may completely flaw the results as well, but we're off topic and I'm not going to get into it. Carry on....
And I'll put this out there... IMO, there is no such thing as true level matching across different preamps.

Different pres will accentuate (or not accentuate) certain frequencies. One may reproduce low end better whereas one may have a mid-range bump. Because of this RMS will feel different because of frequency response. So use peak levels? Same problem... Then gain structure. How are you matching levels? Analog? digital? What if your pres have different step levels (thinking of Forssell vs. Pueblo I believe it was 2 vs. 2-1/2 dB steps)

Just throwing a wrench in there (because that's what I do... )

--Ben
Old 24th September 2013
  #57
Gear maniac
 

Quote:
Originally Posted by fifthcircle View Post
And I'll put this out there... IMO, there is no such thing as true level matching across different preamps.

Different pres will accentuate (or not accentuate) certain frequencies. One may reproduce low end better whereas one may have a mid-range bump. Because of this RMS will feel different because of frequency response. So use peak levels? Same problem... Then gain structure. How are you matching levels? Analog? digital? What if your pres have different step levels (thinking of Forssell vs. Pueblo I believe it was 2 vs. 2-1/2 dB steps)
But maybe this is OK...even desirable? All other things being equal, maybe the various subtle accentuations/enhancements are the very thing to differentiate between these preamps in the "clean" category? Perhaps these are the things that listeners perceive as the subjective qualities between them?

Of course, measuring these things quantitatively gives us a scientific basis for comparison, but maybe in the interpretation of all things musical, it all still boils down to subjective analysis?

Someone earlier recommended using an acoustic guitar for the tests (darned if I can't find this now...), but I've sometimes found acoustic guitar samples difficult to analyze. There's just too much going on with a guitar that can mask features/weaknesses. Perhaps if you're in the control room listening to the samples on monitors, it's easier to compare. But once you compress the files to post here, it becomes problematic. To me, the best source is voice, either female or male.
Old 24th September 2013
  #58
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Maybe I'll just focus on mpr3's suggestion: Have fun!

Rumors are there might be a Gordon included in the tests.
Old 24th September 2013
  #59
Lives for gear
 
Rumi's Avatar
 

Thread Starter
Quote:
Originally Posted by bcfromfl View Post
But maybe this is OK...even desirable? All other things being equal, maybe the various subtle accentuations/enhancements are the very thing to differentiate between these preamps in the "clean" category? Perhaps these are the things that listeners perceive as the subjective qualities between them?

Of course, measuring these things quantitatively gives us a scientific basis for comparison, but maybe in the interpretation of all things musical, it all still boils down to subjective analysis?
Yes, that's interesting! The biggest difference between the Forssell and the NPNG - apart from the low mid forwardness and solidity the Forssell has - in Syra's comparison was for me that the NPNG sounded more lively, the Forssell a tiny bit more static. They handle dynamics differently.

I am not saying at all that the Forssell is a bad unit, it's just that the NPNG sounded the most relaxed and lively of them all.

Quote:
Originally Posted by bcfromfl View Post
Someone earlier recommended using an acoustic guitar for the tests (darned if I can't find this now...), but I've sometimes found acoustic guitar samples difficult to analyze. There's just too much going on with a guitar that can mask features/weaknesses. Perhaps if you're in the control room listening to the samples on monitors, it's easier to compare. But once you compress the files to post here, it becomes problematic. To me, the best source is voice, either female or male.
That's interesting! I always found tests with vocals files pretty irrelevant. But then again they were all different takes, and thus all over the place. Maybe the same take through the same type of mics, with more distance than the usual pop record, so that they have an even distance - that might be revealing.
Now, do you really want to hear me sing?
Old 25th September 2013
  #60
Gear maniac
 

Quote:
Originally Posted by Rumi View Post
Now, do you really want to hear me sing?
I think that would be great to have you perform your own tests!

Something else to consider is this: depending upon how you do your sound source, and whether or not there is repetition involved, you may want to consider using a trained bel canto singer. The reason is that classically-trained voices are accustomed to years of exercises to train their voice to sound the same, each and every time, across a wide range of notes. Having such a singer perform something as mundane as a repetitive exercise up and down a scale would be infinitely more valuable than hearing another singer trying to vocalize a melody the same way for several different takes (if, in fact, this is how you'd have to do your tests).

The important thing, of course, is for each test to be as identical as possible to the others. Maybe even calls for a pre-recorded sample to be used?
New Reply Submit Thread to Facebook Facebook  Submit Thread to Twitter Twitter  Submit Thread to LinkedIn LinkedIn  Submit Thread to Google+ Google+  Submit Thread to Reddit Reddit 
 
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump