From the live Mix with the Masters masterclass : Answering : "What is your favourite phaser", Xavier quotes the UAD MXR flanger, "even though it's not a phaser"

Used on Lamar's vocals for "All the Stars" as stated by producer Matt Schaeffer in this May 2018 Sound on Sound interview.

Kendrick Lamar’s vocal audio tracks, named after his teenage stage name K.Dot, consist of his first verse rap track, ‘VS 1 LD’, and 10 tracks for three moments in the track where he sings the pre-hook in a robotic voice. The verse rap track only has the AIR Flanger on it, and is sent to the ‘Dot VS LD’ aux track, which has eight inserts and five sends. Nine of the 10 pre-hook tracks have Auto?Tune, while the top four have a number of plug-ins on the inserts, including the EQ3 seven-band, Waves RVox, UAD Galaxy Tape Echo, SoundToys Little AlterBoy, SoundToys MicroShift and Valhalla Vintage Verb. These four are sent to a ‘Hook Ref’ aux track higher up in the session with another four plug-ins on the inserts and five sends. The other six are backing vocals to the four other pre-hook tracks and have no other plug-ins, other than a Trim, and are sent to a ‘Hook Background’ aux, just below them, which itself also is sent to the ‘Hoof Ref’ track. It’s a pretty complicated vocal signal chain, as Schaeffer admits.

“The ‘Dot VS LD’ aux indeed has a lot of stuff on it! I did most of the processing on that bus. On the inserts there are the SSL E-Channel, Waves RComp, Waves Q10 EQ, Waves DeEsser, UAD LA2A, UAD Pultec EQP1A, SoundToys Decapitator and Pro?Q2. The SSL channel strip, Q10 and RCompressor remain from the tracking, and maybe the DeEsser as well, but I most likely messed with the settings more during mixing. The Q10 has a high-pass at 50Hz and I notched out a frequency that was bothering me around 8.5kHz with the Q2. I added the other plug-ins during mixing, and they all add something a bit different. I’m boosting 100Hz and 16kHz with the EQP1A. As I said, I like using several EQs on one thing.

“The sends go to a ‘FlangeVerb’ track, on which I put the RVerb and the UAD MXR Flanger, then the ‘Huge Verb’ with the [Audio Ease] Altiverb and EQ3, ‘Hook Valhalla’ with the Vintage Verb, and the SoundToys EchoBoy, the ‘EMT250’ aux with the UAD EMT250, Valhalla Plate and MicroShift, and then finally a send to the ‘Dot VS Delay’ track, with the EchoBoy, set to quarter note, the Reel Tape Flanger and the RCompressor. The EchoBoy is the main delay you can hear in the verse. The EMT250 is not set to a reverb, but to a phaser effect, which gives a cool stereo effect. The Valhalla adds a bit of reverb here, though it’s set to -12, so it only gives a tiny bit of ambience, and the MicroShift makes the whole thing a little wider. It probably still sounded a bit dry, which is why I sent the track to the ‘Huge Verb’ aux with the Altiverb, again taking out low end with the EQ3.

“In the pre-hook, Kendrick wanted that robotic sound with tons of effects. The main robotic effect comes from the iZotope VocalSynth, which gives it a vocoder-like sound. There also are some instances of the Little AlterBoy on the lead vocals in the pre-hook, with some formant adjusting and pitch-shifting. I think one of them is set to +12, so that’s an octave up, and another has a lower formant so it sounds pitched down, even though it remains in the same key. All that adds up to make the vocals sound robotic.”

Adding all inserts on audio and aux tracks together, Lamar’s verse rap is treated with a whopping 22 plug-ins! The ‘Hook Background’ aux, meanwhile, has the EQ3 seven-band, RCompressor, SoundToys Panman, a chorus, the MicroShift, the UAD MXR Flanger and the Valhalla Plate on the inserts and has sends to an aux track with the Waves Kramer Tape plug-in as well as the aforementioned ‘Hook Valhalla’ aux with the Vintage Verb, and Echoboy, and it then is routed to the ‘Hook Ref’ track, which has another four inserts and five sends. Phew.

You can see two of these used in Ola's studio at 3:42 in the video. These are the much older version before the blue face but the same, just older and you can see Flanger/Doubler on thr right side.

In this article Illangelo says he used the MXR Flanger from UAD on The Weeknd's vocal for his song "The Hills"

“I think it’s hard to find a really good software flanger; not many developers have managed to get that warm analogue sound. For me, the MXR is the best one out there.

“To be honest, I would have been happy to talk about any of the UAD plugins. I’ve got the whole set and every one sounds incredible.”

Used on the trumpet for Justin Bieber's "Love Yourself", as stated by Purpose mix engineers Josh Gudwin and Andrew Wuepper in this May 2016 Sound on Sound interview about the mixing of the title track and others.

“I didn’t want to add much to the session, but I did continue working on it until it felt right to me. I wanted to maintain the fact that the arrangement is very bare, yet also add small things to make it sound fuller than it is. These small additions are like ear treats. When Phil came in to play his trumpet, I recorded him sitting in a chair, with a Royer mic right underneath and just a Neve pre, and no compression. Right after cutting it, I immediately worked on the sound. I put a reverse reverb on it, and a UAD MXR flanger and a delay. The ‘Audio 1’ track has a trumpet loop that I made, a texture thing on which I had the UAD SPL Vitalizer."