Apollo Twin MKII Distortion Issue - With example

[BrandonUnis]

Hello all,

Really hoping someone can shed some light on this issue I've been battling for the better part of a year. No matter what I try I cannot get a consistently clean vocal recording with my Apollo Twin MKII. I have a ton of recording, mixing and production experience and I've never been stumped like this before. Point form info:

- Currently recording into ProTools 2018.
- Have experienced this with many mics ranging from NT1A to U87
- Have experienced this with just the clean Apollo pre, different unison pre's and even using a SOLO 610 going line in into the apollo.
- levels don't have to go past -18 on the apollo meters for it to happen
- Levels don't have to go over 0VU in pro tools for it to happen.
- It happens with both pre amps on the twin.
- I've tried swapping all cables including thunderbolt.

I've attached an example of it happening with just my voice. NT1A - SSL 4KE Unison pre - LA-2A. I'm UBER confident nothing is being over driven or compressed.

https://www.dropbox.com/s/37ktbccosv...rtion.wav?dl=0

Am I expecting too much out of my apollo? I thought they were supposed to have fairly decent pre amps / converters?

Any and all advice would be appreciated.

[BrandonUnis]

To elaborate one step further. It's less of an overt distortion but it sounds more like a rattle / dirt layer over top at times. At first I thought it was a pop filter issue or a mic capsule issue but I've swapped out all those things many different times to no avail.

If anyone needs more info, don't hesitate to ask!

[Darryl Ramm]

Its not obvious what you mean by "clear" can you describe what artifacts you are hearing, including in the sample you provided. The main think I hear from that is a bit of sibilance in the "yes".

Can you give a demo with no plugins anywhere, nothing happening in the Apollo console, etc.

How are you playing back/monitoring this?

Given VU is another layer or indirection, and is adjustable, can you quote input levels in dBFS.

[BrandonUnis]

Originally Posted by Darryl Ramm

Its not obvious what you mean by "clear" can you describe what artifacts you are hearing, including in the sample you provided. The main think I hear from that is a bit of sibilance in the "yes".

Can you give a demo with no plugins anywhere, nothing happening in the Apollo console, etc.

How are you playing back/monitoring this?

Given VU is another layer or indirection, and is adjustable, can you quote input levels in dBFS.

Thanks for inquiring further!

Sure I can do another recording with all plugins disabled. Will do that in a bit. By not 'clear' its similar to those exact artifacts you hear on the "yes". It's not always tied to sibilance but that was the best example I could get when I was trying. Let me try and create another.

It's like the vocals have dirt / grit on them when they shouldn't. And it happens even if I am SUPER safe with my levels.

I'm monitoring back through my apollo, I hear the "dirt" on my Yamaha HS80s, Avantone Mix Cube and apple ear buds so I don't think it's an issue on that end.

[BScout]

Run a sine sweep in on a loop back (out to in) and record the sweep. If you have REW (download for free), you can do it in that. Don't run any plugins. See (or post) the mdat created of that sweep for issues.

Make sure the level is around 70-80 dB for the sweep.

[BrandonUnis]

Originally Posted by Darryl Ramm

Its not obvious what you mean by "clear" can you describe what artifacts you are hearing, including in the sample you provided. The main think I hear from that is a bit of sibilance in the "yes".

Can you give a demo with no plugins anywhere, nothing happening in the Apollo console, etc.

How are you playing back/monitoring this?

Given VU is another layer or indirection, and is adjustable, can you quote input levels in dBFS.

Ok here's a recording with no other plugins.

https://www.dropbox.com/s/zml40pj5tq...0COMP.wav?dl=0

Of course it's not happening as obviously as it usually does. I do hear it on the line "clean into the apollo".

It's almost intermittent. My last vocal session was going great, then it got time to do some lighter BG vocals and no matter what we did, they were super gritty sounding. Tried singing off mic, playing with levels etc. Eventually got it to a point that it was fine enough since it was just a BG part.

It seems to come and go. It's so strange.

[BrandonUnis]

Originally Posted by BScout

Run a sine sweep in on a loop back (out to in) and record the sweep. If you have REW (download for free), you can do it in that. Don't run any plugins. See (or post) the mdat created of that sweep for issues.

Make sure the level is around 70-80 dB for the sweep.

Ok I think I did this right, here's the results I got. Picture Attached.

[Darryl Ramm]

Is Low-Cut enabled on that input?

I'm assuming that is a line-out to line-in sweep/transfer graph. Please tell us exactly what you are doing....

What gain levels are you using the NT1A at? Distance from mic? (I know you are experienced but I'm grasping at straws here). Using a pop filter? Mic acoustic surround/sound absorbing back panel? I'm waiting for the NT1A haters to jump in

[BScout]

Originally Posted by BrandonUnis

Ok I think I did this right, here's the results I got. Picture Attached.

Did you run a 10Hz to 20+kHz sweep? That sweep looks seriously limited in bandwidth.
What sample rate are you at?
I can see the tell tale ripple in the freq response I see on the unison mic preamps. That's nothing to worry about when you realize the scale but that sweep needs to be done over a larger bandwidth. And what level were you sending/receiving? Since a sine sweep directly in to out should have no peaks, you should be able to run this at fairly high levels to make any problems really apparent (like -6dBFs) (just make sure you don't have speakers going at the same time)

Also, attach/post the mdat if possible (the saved file from REW). It's easier to look at than the graphs (since you can adjust scales/zoom/smoothing)

[BrandonUnis]

Originally Posted by Darryl Ramm

Is Low-Cut enabled on that input?

I'm assuming that is a line-out to line-in sweep/transfer graph. Please tell us exactly what you are doing....

What gain levels are you using the NT1A at? Distance from mic? (I know you are experienced but I'm grasping at straws here). Using a pop filter? Mic acoustic surround/sound absorbing back panel? I'm waiting for the NT1A haters to jump in

Yes sorry that was a line-out line-in sweep. The low cut may have ben engaged by mistake. I disabled the unison pre but that may have transferred to the apollo pre and stayed on.

When gaining the NT1A my preamp is only set to around 20/30% so that my levels on the apollo meters rest around the -18 mark. I've been told that's the sweet spot for these A-D converters. Peaks go above occasionally but it doesn't take a peak to get this grit. Ive been using the LA-2A (but tried other plugins as well) to then boost the signal a bit more, post converters, just so my levels are bit healthier in pro tools.

I've played with distances from the mic, from tight to 6 inches away and still experienced it.

I have a fully treated booth, I'm recorded these demos outside of it in my control room but it definitely happens in the booth.

I know the NT1A will have haters but I did experience this with a TLM 149 and also a U87. So it's not exclusive to a lower end mic..