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creature.of.habit
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Re: no comparison!

Post by creature.of.habit » Thu Jan 25, 2007 5:56 am

AudioJunky wrote:I have not heard a U47 in my life
of course you have, you just don't know it's it. :wink:

personally, i think Michael's work is beyond question, outstanding in every aspect, and i would and will do business with him again. the neumann comparisons are the only thing that makes real sense here, you have to aim high, i totally agree with this policy.

i have not listened to these particular clips, but listened to most of the ones on Michael's website and i can't honestly tell most neumann clips from the 319/219 ones.

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Post by douglas baldwin » Thu Jan 25, 2007 6:46 am

An excellent blindfold test, Michael. I am not going to vote, as I wouldn't know what a U48 is supposed to sound like, nor what the unmodded Oktava mics originally sounded like.

I found much to like (and something to dislike) in all three mics. I listened to very specific moments in each file, skipping back and forth. For midrange and high end response, I listened for the sibilance of the word "seeing" (0:02); the capturing of the wavering pitch on the word "small" (0:13); and the caught-in-the-throat emotion of the phrase "I'll always think of you that way" (0:30). For bass response, I listened to the "you" (0:03) and "carousel" (0:19).

My observations:
* Mic 1 was the most accurate, with the least bump in the bass. It had the most natural air overall, and particularly on the "seeing" at 0:02. It captured the pitch waver of "small" (0:13) beautifully - in fact, it was the mic that led me to listen for that moment. However, it was not as kind to the tone of "I'll always think..." (0:30), sounding a little resonant and tubey in the 4-8K range.
* Mic 2 was the most "Norman Normal," with slightly humped bass, less air, and it missed the pitch waver of "small."
* Mic 3 was a close second to mic 1. It was a little furrier, huskier in the bass, it captured the emotion of "I'll always think...," and it captured the detail and delicacy of the pitch on "small" (0:13).

But I wouldn't send the UPS guy away from my door if any one of them showed up today. Now that you're done with them, Michael, drop me an e-mail and I'll give you my mailing address. :D
Douglas Baldwin, coyote in residence
Music and writings
Psychedelic pop and ambient soundscapes a specialty
www.thecoyote.org

* * * * * * * * * * * * * * * * * *

GREGL
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Post by GREGL » Thu Jan 25, 2007 7:09 am

I'll bet you could plug the 3 mics into a different preamp and it would completely change the results.

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Post by PIJN » Thu Jan 25, 2007 10:43 am

GREGL wrote:I'll bet you could plug the 3 mics into a different preamp and it would completely change the results.
I would bet you could use interface pres also with good results :D

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Post by qball » Thu Jan 25, 2007 5:25 pm

I listened closely to the audio samples. I don't intimately know the sound of an actual U48 so I'll just comment on the differences I can pick out between the 3.

#1: This would be the one I'd pick for guitar. It has more sparkle and not as much of a low end hump. It might prove to be slightly sibilant on some voices.

#2: This one sounds the smoothest in this application. It has just enough presence without hinting at sibilance. the low mid hump gives it a larger "classic" sound. I'd pick this one for vocals.

#3: To my ears this one sounds less detailed than the other two - not by much, just a touch. Maybe it's because it has a bit of hair on the top. This mic kind of reminds me of a ribbon mic. Similar to #2, this one has a nice low mid beefiness often associated with the older classic mics. The hump seems to be a slightly different frequency than #2, but still in that nice plump zone. If I were forced to guess which one is the U48, this would be the one I'd pick just because it has the sound that I'd imagine a U48 having.

All of these mics sound fantastic! No matter which ones turn out to be Oktavas, I'm going to have one scheduled for the mods. Not because it sounds very close to a U48 - but because they sound damn GOOD. :D And to be able to have that quality of sound for just a few hundred bucks is VERY appealing indeed!
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Post by PIJN » Thu Jan 25, 2007 10:38 pm

I guess some of these thread guys are on vacation?

I wish I could take one.....

Instead I am always stuck to the grind of listening and learning.... and not talking much.

Arnt you guys listening to any of these he has placed?

I will be with you guys in vacation some day! :cry:

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Post by nlmd311 » Fri Jan 26, 2007 10:35 am

Man,
These are ridiculously close to my ears. I can only hear very subtle differences at certain times in the clips. I almost feel as though this is a nasty joke! :suspect:
Anyway, I own an Oktavamod modded MKL-2500 (as well as MK-319) and of the three clips I would say the second is the one I feel most closely resembles the characteristics I know of my 2500. I would side with clip 1 also being an Oktava and clip 3, although I have never personally used one, would be the U48. Clip 3 does seem to have a different character than 1 and 2, but could that just be the difference between the cathode follower and plate load versions?
I'm confused.

When will we know?

-Darrill
slowly panning across something kind of crappy...

qball
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Post by qball » Sat Jan 27, 2007 6:50 am

Looks as if the audio samples shut down the skeptics! Way to go Michael! :wink:
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Michael_Joly
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MKL-2500 hum reduction

Post by Michael_Joly » Mon Jan 29, 2007 11:54 am

While we're waiting for the polls to close on the U48 / MKL-2500 blind test and the results to be revealed (364 downloads so far and only 8 voters :cry: , cast your anonymous vote at http://tech.groups.yahoo.com/group/OktavaMod/polls) here's another tip that can reduce the hum in MKL-2500 mics sold with Chinese power supplies.

Some time ago, "slowjett" posted some tips on the Gearslutz site for reducing or eliminating the hum in the MKL-2500: http://www.gearslutz.com/board/showthre ... light=2500 Because these recommendations are not always 100% effective in all Chinese 2500 power supplies here's an additional technique that might work.

Last week I had two identical Chinese powers supplies for the MKL-2500 on my bench, one had hum and the other did not. I discovered that by adding a jumper from the top end of D10 to the buss wire at the XLR connectors I was able to reduce the hum by about 8-10dB. This jumper more effectively ties these two ground points together to eliminate the ground potential voltage difference between them, thus reducing ground current flow that is amplified and heard as hum. So far this has worked on three Chinese MKL-2500 power supplies I've tried it on. Btw - slowjetts suggestions should be carried out first .

The pic below shows where I used a double length (for lowest resistance) of white insulated wire to create this jumper.

There seems to be both ground loop issues and high AC ripple issues in these power supplies. I have not tried increasing the uF value of the filter caps yet but that could only help matters.


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AudioJunky
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Mic Tests

Post by AudioJunky » Wed Jan 31, 2007 5:39 pm

For what it is worth, after the first comparison I was in favor of the U48- after listening to the next set of examples, I still have the same opinion of the first example- but the more recent examples are definitely way way closer to each other. Maybe cuz the guitar is not in the picture? I'm not sure. Either way- can't wait to see the results.

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Michael_Joly
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U48 / OktavaMod MKL-2500 Blind Test Results

Post by Michael_Joly » Sat Feb 03, 2007 6:23 am

Here are the results of the U48 / OktavaMod MKL-2500 blind test:

Vocal 1 = Neumann U48

Vocal 2 = OktavaMod MKL-2500 plate load

Vocal 3 = OktavaMod MKL-2500 cathode follower

Anonymous blind test voting results show Vocal 1 and Vocal 3 to have been chosen as the U48 about equally.

I believe difference between the cathode follower and plate load mics in this vocal test may be related more to capsule differences than circuit topology. I would expect there to audible difference with high peak factor material like percussion though. A cathode follower topology has tremendous headroom (almost impossible to have a LDC capsule clip a cathode follower) while the plate load has what we recognize as "soft clipping" on extreme peaks. Btw - the MKL-2500 mics were shipped from the factory with both cathode follower and plate laod topolgies - I don't change them from one to the other.
Last edited by Michael_Joly on Sat Feb 03, 2007 7:07 am, edited 3 times in total.

qball
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Post by qball » Sat Feb 03, 2007 6:40 am

Kewl, now I know which mod to have done! :D :D :D
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Brian
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Post by Brian » Sat Feb 03, 2007 7:09 am

I think #2 is the 48, I grew up using the entire Neumann line at Big Apple Studios and #2 sounds like one to me, big in the mids, made to sound good with minimal adjustment on AM RADIO! That's right.
To my ears, the OktavaMods are more pleasing to the ears because the mids seem silkier, the highs seem a little clearer and sheeny, the bass is tight, BUT, the mids on the 48 seem more "inyoface" which can be necessary down a long signalpath.
Mike, I think a way to test the mics would be to put a 10-50khz "sweep blip" down them and measure for transient response and frequency response and that would be the telling measurement. The transient response, if it can be measured this way, could be per bandwidth or frequency. That would really tell the story. The neuman's in general sound like they are in a cardboard box campared to the mods. Boxy mids, however I think it sounds like a time issue rather than an EQ issue, like the slew rate on the neuman is either faster or slower but more "hearable".
The Oktava Mods sound more "Pillowy soft" I like them. Now, If I was just blindly picking a mic out of the box and had to A/B to find a good one, the mods would win.
The Neumans are relegated to the "If I need this" Pile! Mods are "Go To"
I'm the guy that made those mods back in the early thread days when we first started this 3 yrs back, with those Big Long Blue caps, to which you said, "look at the sag!" I still laugh when I look at the pics. They sound great though.
Harumph!

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Brian
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Post by Brian » Sat Feb 03, 2007 7:13 am

Oh, has anyone tried re machining to get a few extra mm of interior diameter on the 319 chassis???
Harumph!

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Michael_Joly
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Post by Michael_Joly » Sat Feb 03, 2007 11:35 am

Brian wrote: To my ears, the OktavaMods are more pleasing to the ears because the mids seem silkier, the highs seem a little clearer and sheeny, the bass is tight, BUT, the mids on the 48 seem more "inyoface"...The neuman's in general sound like they are in a cardboard box campared to the mods. Boxy mids, however I think it sounds like a time issue rather than an EQ issue...
Brian, interesting observation - especially the differentiation between time domain and frequency domian issues and how this contributes to the U48's "in your face" presence.

One of the major differences between the U48 and modified 2500s is the headbasket. The multiple grille layer U48 headbasket (with a fairly low percentage of open area) and resultant closely-spaced (in time) reflections contributes a good deal to the charactericstic sound of this mic, while the modified 2500s headbasket (single layer, fairly high percentage of open area) does not cause the kind of internal reflections between capsule and grille as does the U48 headbasket.

A headbasket with less open area is going to act more like a little cave around the capsule and affect the time domain performance of that electro-acoustical system. I hear the modified 2500s headbasket as being more "open" and less colored - especially in the articulation and differentiation of "S" and "Sh" sounds.

Stephen Paul writing in his seminal 1989 MIX Magazine article touched on the subject of headbaskets when he discussed the sonic differences between the U47 and the U49 - both M7 capsules equipped mics.

Stephen wrote "...The 49 (was) one of the first attempts to limit the effect of grille resonance on the response. Because the grille is slanted and presents a continuously varying profile to the capsule, there are fewer standing waves generated...The 49 is especially good on female vocals. Not having quite the ?nasality? that the 47 is known for, it has a smoother high-frequency range, and the size of the grille forms a larger-volume enclosure giving the capsule more breathing room and contributing to its ?openness.?

In another installment of his article Stephen alluded to the difference between the AKG C12 with its single-layer headbaset and the 251, which in addition to its outer wire grille mesh, had a "relatively dense nylon mesh in the grille, which lent the top end a pastel character."

But to take a totally different tack here, there is something special about working with U47 / 48s. (Aside from the almost indescribable "presence" I hear in them). When the talent stands in front of a U47/U48 and lets a vocal fly its like they're participants in the long life of a legendary microphone that has heard many takes from many singers before. There is a sympathetic vibe between the mic and performer that does count for something and this can contribute to getting those "magic" takes.

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