AKG Perception P220 to Neumann u87 5 min mod ( p200, p100, p400, p420? )

[user 140861]

Here's the effect of a headgrille. U87 is designed to have a transparent one.

https://groupdiy.com/threads/wa-47.79979/post-1047689

There's also this, position of the capsule is also important.

Post in thread 'Effect of capsule height in head basket' https://groupdiy.com/threads/effect-of-capsule-height-in-head-basket.84530/post-1097866

Thanks for this kingkorg! I've never thought those factors would affect the frequency response

 

[kingkorg]

Thanks for this kingkorg! I've never thought those factors would affect the frequency response

It's acoustics. Like in a room, same rules apply. Reflections cause nulls, and bumps, unless the distance is so short they don't affect audible range.

 

[kingkorg]

I don't know how to thank enough @Wordsushi for content like this, and his kind words. This is exactly why i post my findings, and propose possible mods. Thank you man!

 

[Wordsushi]

My absolute pleasure. You have been the single biggest influence in my microphone DIY journey over the years. It has now turned into a full-blown obsession.
This mod is legit. And I'm now really thinking this Takstar CTS-2 capsule has an incredible midrange with a very Neumanesque purr to it.

 

[mikes425]

Hi! Mark's video reminded me of this and I did get this mod done by an engineer I used to work with about 6 months ago. He used a 540 pF cap. It did seem to be an improvement when i
checked it out that week...A/B'ing to an 87Ai. Thing is...for some reason i must've totally spaced
out when i chose the donor mic to give him...but...turns out I gave him a Perception 200, not a 220.
This i just discovered when i pulled the mic out to re-listen to it!
So is there any actual difference technically between these two models.. the 200 vs 220?...and as long as I'm at it, other than the Fig 8 option, any reason i'd want to do a 420 vs a 220 if i chose to have another of these mods done??

One thing that bothers me about my 87ai is its sterile ultra-sensitivity to every tiny nuance of movement. Not that there's anything wrong with that - it is what it is - but...for VO...ideally
a mic with more forgiveness tends to be my preference - especially for rapid editing of material.

Main question tho, can someone confirm that the 200 is essentially the same capsule and circuitry as the 220? (and i'm referencing the original Perception series, not the newer "P220, P420 series).

Thanks for any insights!

 

[kingkorg]

One thing that bothers me about my 87ai is its sterile ultra-sensitivity to every tiny nuance of movement. Not that there's anything wrong with that - it is what it is - but...for VO...ideally
a mic with more forgiveness tends to be my preference - especially for rapid editing of material.

Nothing to do with 87ai. This is inverse square law. For every doubling in distance you get halving of signal level.

You are too close to the mic.

If you are one inch away, moving one inch will cut signal level in half. If you use mic 1 foot away, you would need to move 1 foot to halve the signallevel, and so on. You need to move away from the mic to make it less prone to movement.

Joe Rogan syndrome. He's eating his mic, and then spends whole show reminding his guests to do the same. Instead of treating the room properly, and use typical, well proven overhead technique.

 

[mikes425]

Nothing to do with 87ai. This is inverse square law. For every doubling in distance you get halving of signal level.

You are too close to the mic.

If you are one inch away, moving one inch will cut signal level in half. If you use mic 1 foot away, you would need to move 1 foot to halve the signallevel, and so on. You need to move away from the mic to make it less prone to movement.

Joe Rogan syndrome. He's eating his mic, and then spends whole show reminding his guests to do the same. Instead of treating the room properly, and use typical, well proven overhead technique.

Thanks! Great point. That is how I've always-(well usually)- been set up with an 87ai in sessions at studios I work with... so yes, i totally get it...and need to position further away in my smaller 'booth. You remind me of a session decades ago where they had the 87 an inch from my face with a room full of agency directors and Creatives all weighing in. On the second or third take one was chiming in about hearing some rustling noise under the voice - which was 'determined' to be my headphones slightly shifting on my head with my hand gestures. IIRC the engineer, to save face, blamed me for 'bad technique' LOL.

I was just A/B'ing the modded 200 model i had done with a 540 pF cap against my 87ai. Quite impressive. I can hear where the higher value cap might've been a little richer in tone but...honestly after level matching, the mid-range character and overall tonal similarity between the two is quite impressive!

Thanks!

 

[k brown]

Nothing to do with 87ai. This is inverse square law. For every doubling in distance you get halving of signal level.

You are too close to the mic.

If you are one inch away, moving one inch will cut signal level in half. If you use mic 1 foot away, you would need to move 1 foot to halve the signallevel, and so on. You need to move away from the mic to make it less prone to movement.

Joe Rogan syndrome. He's eating his mic, and then spends whole show reminding his guests to do the same. Instead of treating the room properly, and use typical, well proven overhead technique.

Inverse square drops the the level to 1/4 as distance is doubled, not 1/2 (at greater distances and reverberation starts getting involved, things get a bit more complex).

https://audiouniversityonline.com/inverse-square-law-of-sound/

Same applies to light, as well.

 

[kingkorg]

Inverse square drops the the level to 1/4 as distance is doubled, not 1/2 (at greater distances and reverberation starts getting involved, things get a bit more complex).

https://audiouniversityonline.com/inverse-square-law-of-sound/

Same applies to light, as well.

Sorry, i think you got something wrong there. For every doubling in distance you lose 6db, which is half. Feel free to use any calculator available. Even if we don't agree, the point of my previous reply remains. You don't want the mic too close.

https://www.engineeringtoolbox.com/inverse-square-law-d_890.html

 

[Paul W]

Isn't 6db a doubling of voltage but a quadrupling of power because the energy is proportional to the square of the amplitude? (Because doubling the amplitude doubles the velocities and KE = 1/2 mv**2)

 

[k brown]

The link in my post explains it pretty clearly.

 

[k brown]

Isn't 6db a doubling of voltage but a quadrupling of power because the energy is proportional to the square of the amplitude? (Because doubling the amplitude doubles the velocities and KE = 1/2 mv**2)

In this context we're referring to the db (decibels) as a unit of sound intensity.

 

[k brown]

Confusing. Some websites say sound falls off the square of the distance, others say 6dB at double the distance - they seem contradictory.

 

[kingkorg]

Confusing. Some websites say sound falls off the square of the distance, others say 6dB at double the distance - they seem contradictory.

Well, my spl meter agrees with -6db at distance doubling. This is what i've been using for measuring extremely high SPL, and checks out every time. Has to be a glitch with interpretation of the theory.

 

[Khron]

So is there any actual difference technically between these two models.. the 200 vs 220?...and as long as I'm at it, other than the Fig 8 option, any reason i'd want to do a 420 vs a 220 if i chose to have another of these mods done??

200/400 have -10dB pad switches, 220/420 have -20dB pads, that's it. Other than some external minor details of the housing.

400/420 have cardioid / omni / fig-8 (not just cardioid & fig-8).

 

[micolas]

200/400 have -10dB pad switches, 220/420 have -20dB pads, that's it. Other than some external minor details of the housing.

400/420 have cardioid / omni / fig-8 (not just cardioid & fig-8).

I agree with @Khron , I've noticed over time that the 200/220 versions sound similar.
But they are slightly different sonically from 400/420, something pointed out by @kingkorg in older posts, and highlighted by measurements.
I can also confirm that after modding the P420 sounds different from the P220, being closer to the U87ai, with slightly sharper, incisive high-mids/highs, with more bite to paraphrase @Wordsushi
I like the low frequency response of the AKG more than the Neumann, bigger, rounder, with more weight.

 

[ccaudle]

Inverse square drops the the level to 1/4 as distance is doubled, not 1/2

The link you posted states -6dB SPL for doubling of distance, double the distance half the SPL.

As explained at the link the sound intensity decreases as the square of distance, the sound pressure level decreases proportional to distance.

 

[mikes425]

I agree with @Khron , I've noticed over time that the 200/220 versions sound similar.
But they are slightly different sonically from 400/420, something pointed out by @kingkorg in older posts, and highlighted by measurements.
I can also confirm that after modding the P420 sounds different from the P220, being closer to the U87ai, with slightly sharper, incisive high-mids/highs, with more bite to paraphrase @Wordsushi
I like the low frequency response of the AKG more than the Neumann, bigger, rounder, with more weight.

Interesting details, thanks! I don't have graphing to compare with, but had a 200 modded with a 540 pF cap. That value seemed appropriate because I wanted something closer to the 87Ai than the more neutral 87 character. Does that make sense...or, would you think it would be worth modding say, a P420, with a different cap value (like a 680 pF). I may very well be over-thinking this : ) but just curious what the optimal combination of donor mic and cap value would be if i want to replicate the 87Ai as faithfully as possible. Thanks!

 

[mikes425]

Inverse square drops the the level to 1/4 as distance is doubled, not 1/2 (at greater distances and reverberation starts getting involved, things get a bit more complex).

https://audiouniversityonline.com/inverse-square-law-of-sound/

Same applies to light, as well.

So in terms of the issue of sensitivity/pickup of mouth noises or those slightest nuances of movement - with mic placement of say..overhead, 8-12" or more away from the talent, logically the differential in distance still requires boosting preamp levels....but you're suggesting the mic would still be less likely to pick up such noise just by nature of the distance from the diaphragm vs 'close-mic' proximity even with gain 'make-up' for decent record levels?

 

[micolas]

Interesting details, thanks! I don't have graphing to compare with, but had a 200 modded with a 540 pF cap. That value seemed appropriate because I wanted something closer to the 87Ai than the more neutral 87 character. Does that make sense...or, would you think it would be worth modding say, a P420, with a different cap value (like a 680 pF). I may very well be over-thinking this : ) but just curious what the optimal combination of donor mic and cap value would be if i want to replicate the 87Ai as faithfully as possible. Thanks!

In the new model, P420 Black, I left the stock capacitor on the PCB and soldered two wires in parallel taken out, to be able to test different values.
I did a lot of tests.
With 360pf externally I liked it, very close to U87ai. So in total it would be
220pFstock+360pF=580pF
I'd say a 560pF gets you there.
For something flatter, U87i towards 67, I found a 680pF for the outside, so a total of 900pF.
And now the wires are still out, I like more nuances of sound.
I'll figure out a way to put a switch with multiple positions for different flavors.
So if you remove the stock capacitor and put another one in its place, 540...560pF should be fine for U87ai.
I remember that Kingkorg achieved with 680pF, a sound close to the vintage U87i, with the Perception 220, an older model, which may have suffered a little aging of the capsule.
Considering that all components have tolerances, it's best to test different values for the capacitor to taste.