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+--- Thread: PZM Experiments (/thread-339.html)
PZM Experiments - physics - 12-27-2024
I have a Crown PZM-6R on it's way to me right now via second-hand online shopping, so I'm starting a thread to post and discuss experiments I do with it once it arrives. Fingers crossed for awesome sounds.
RE: PZM Experiments - physics - 12-29-2024
Small update: the mic arrived, it does what it says on the tin. The recording sounds very close to what I hear in the room, even with less than ideal monitoring (cheap ear buds). My brother remarked during playback over the car stereo that it was uncanny how much it felt like he was in the house listening to me play. I'll post some clips when I get a chance, but I think this is a keeper. Only issue is now I can clearly hear things I need to change in my rig. The hunt for TUT continues...
RE: PZM Experiments - Strelok - 01-21-2025
Hey Physics!
Having fun with the mic?
How do you record, with the mic pointing at the cone or with the mic alongside the speaker?
Strelok
RE: PZM Experiments - physics - 01-21-2025
(01-21-2025, 11:34 AM)Strelok Wrote: Hey Physics!
Having fun with the mic?
How do you record, with the mic pointing at the cone or with the mic alongside the speaker?
Strelok
Howdy!
Yes, lots of fun. Been meaning to post, but haven't got around to it. The short story is that if I use my ears to find where in a room things sound good and then stick the mic there, the recording sounds very close to what I heard with my ears. Here are a couple clips:
Yamaha CG172SF with bone nut and saddle, and La Bella 2001 Flamenco Light Tension strings. PZM-6R taped to sizable sliding glass door about two feet or so in front of and a bit above the sound hole.
https://soundcloud.com/grrrrr-662986275/yamaha-cg172sf-pzm-6r/s-cO6geIGeiie
'82 4104 JCM800 with stacked boosts/overdrives into a Yamaha 4x12 w/Celestion V30's. PZM-6R around 15ft or a bit more into the room off to the side on the wood floor. Master volume upwards of 2 I think.
https://soundcloud.com/grrrrr-662986275/diary-boosted-and-distorted/s-sNiNUj8AjdI
Same JCM800, but through it's 2x12 cab loaded with EV Force 12 speakers. No stacked boosts this time, only 12dB of clean boost with just a bit of presence added via an EQ pedal. PZM-6R on the carpeted floor about a foot or less from the center of the cab. Special note for these recordings: it was past 12am when I recorded these, so the master volume on the amp was almost off. I could easily talk over it, and you can easily hear the acoustic sound of my strings.
Same riff as the room mic for comparison:
https://soundcloud.com/grrrrr-662986275/diary-max-boost/s-dKg3qJHP1yD
And the two best sounding (aside from playing) tracks I've got of the amp so far.
https://soundcloud.com/grrrrr-662986275/lay-it-down-max-boost/s-jDRWqEmFjcd
https://soundcloud.com/grrrrr-662986275/unchained-ish-max-boost/s-2Z1jsgYROsP
As far as the how of recording, the mic has a hemispherical pickup pattern. The mic itself looks like this:
![[Image: 1d3619c57cc1927b4a35a4c69cee5767.jpg?c=X...iTGVQk-8cl]](https://kagi.com/proxy/1d3619c57cc1927b4a35a4c69cee5767.jpg?c=X82_99pbEv56109AQHEqmaq6uxRMkGRP_Qk4jrs0KhBvN5JgSM6SNT9DqnpJotN97zgFDFgOUwgnpL0ZugfiJAtk_iJy_ZVZnZkmr4DcXaNSZvlnJVSqwCiTGVQk-8cl)
I just stick that plate on the floor, wall, or wherever I think it sounds good in the room. Ideally facing the nose towards the sound source when that makes sense geometrically (i.e., when it's on the floor or far up a wall). The clips I recorded at midnight volume levels though I got by just sliding the mic along the carpet until I found a spot where it sounded decent enough. Technically, it should be a hard flat surface that you place the mic on, so the carpet might have affected things but I'm not sure how at the moment as I didn't stick my head at that spot to check how it sounded to me. Some people also just get a sheet of plywood and stick the mic on that, then they place the plywood a few feet in front of the amp. Or, similarly, sticking the mic on the wall and the amp a few feet away pointed at the wall. When I get a chance I'll recorded some higher-volume clips of both a "room-ish" setup with the mic 8ft away or so in a place I think sounds good, and a "close" setup with the mic on a wall with the amp pointed at it. The thing with these mic's is that the low end response is affected by how big of surface you stick 'em on, so if I were to do a "traditional" close-mic technique the result would be a flat 6dB drop from around 1kHz to DC if I remember correctly. Though I suppose that's worth a shot too just to see what I get.
RE: PZM Experiments - physics - 01-21-2025
One other note on my experience with the mic so far:
I got to use it in a studio session with a friend who's working on a passion project. I set my amp up, and since neither of us have much experience close-micing I suggested we try the PZM first since it might be easier. I plopped the mic around 2ft in front of the detuned 2x12 I brought for recording just to start things off, and what we got back through the monitors was almost identical to what we heard in the room. From there we just moved on to actual tracking and left the mic where it was.
RE: PZM Experiments - physics - 02-09-2025
A couple more clips I recorded after replacing the input jacks on my 4104. The PZM is on the wall about 2ft in front of the amp. I have about 12dB of clean boost between the guitar and amp input. The amp isn't particularly loud 'cause it was later in the day, but it wasn't whisper quiet either. Somewhere < 1 on the master volume.
https://soundcloud.com/grrrrr-662986275/take101_fresh-jacks-wall-1-1/s-SqPV8IJfiDT
https://soundcloud.com/grrrrr-662986275/take102_fresh-jacks-wall-1-1/s-32WwST2NCK5
RE: PZM Experiments - physics - 02-09-2025
Another track i recorded today with basically the same setup, but with the amp louder. Double-tracked.
https://soundcloud.com/grrrrr-662986275/creeping-death-pzm-on-wall-12db-boost/s-4hMVmUZx8m6
I like the tone, but I'm definitely feeling the lack of a detuned cab now that I'm working with an open-back 2x12. I'll have to take advantage of the local maker space to fill that gap.
RE: PZM Experiments - physics - 02-18-2025
I got some different results after toying around with mic placement and beam blockers/acoustic lenses. I'll post them later this week.
RE: PZM Experiments - physics - 02-25-2025
Almost made it within the week. I tried centering the mic on-axis with one of the speakers to get more presence and high-end, as opposed to being so far off-axis like I was previously. Boy, did that bring it back. Enough that with the settings I was running (EQ maxed) a beam blocker was necessary to kill icepick treble. The beam blocker I used was an open-cell, polyurethane, 1.4 lb/ft^3 density, foam disc sized to the speaker cut-out hole, with a 3" diameter hole cut in the center. The basic operational principle being that the disc makes the speaker behave like a smaller sound source at higher frequencies, killing off a good bit of the constructive interference patterns that cause beaming. At some other point I plan on doing some comprehensive tests to post for listening and/or discussion, but for now here's the clip. EQ maxed, Presence at 6/10, Pre-Vol at 7, MV just above 0 if I remember. https://soundcloud.com/grrrrr-662986275/creeping-death-on-axis-beam/s-awAIpKmH4te
Here's another riff, played too slow and not perfect, but chasing "feel" is another thread, possibly another forum. I've included a "no-beam-blocker" version first to show how much it did. This particular riff brought out the worst in my setup I think. Pretty fizzy/shhhh-y and a bit hollow.
No beam blocker:
https://soundcloud.com/grrrrr-662986275/unchained-on-axis-square-wall/s-jLv9jtYcxQ4
Beam blocker:
https://soundcloud.com/grrrrr-662986275/unchained-on-axis-square-beam/s-a2q08GFPJ0a
To try reducing the hollow and fizzy quality, I reduced the Treble from 10/10 to 7/10, and also moved the cab a little closer to the wall in case it was a resonance issue (but I don't think it was). Aside from that, and an even lower master volume, the settings were the same. Here are the two riffs from before, but with this new setup. https://soundcloud.com/grrrrr-662986275/creeping-death-less-bright/s-PVOS2AaT84e https://soundcloud.com/grrrrr-662986275/unchained-faster/s-aqo0Dt00POh
I think it sounds pretty darn good for the volume being somewhere below 0.5/10. Can't wait until I can do a MV and/or power scaling mod and build a detuned cab or two. I have some clips of riffs that I recorded with both the PZM and an SM57 for comparison which I'll post at some point, but for now I gotta get going. If anyone has critiques of the clip tones I'm happy to hear them.
Edit: Oh, and all clips were with 12dB of clean boost in front of the amp.
RE: PZM Experiments - physics - 05-07-2025
Got a 4'x4' piece of plywood to mount the PZM. Using that, I stuck the PZM where I like to stand in the room when playing my amp and recorded some quick messing around.
Clean: https://soundcloud.com/grrrrr-662986275/take303_pzm-4x4-1-1/s-LZS0Ix8ZUGl
Dirty and boosted with a Timmy pedal: https://soundcloud.com/grrrrr-662986275/take304_pzm-4x4-1-4/s-YrQk06VVcjX
I think the overall tonality is fairly good, but it has more of a echo-y room quality than I'd like. I'm thinking that I can either position the mic closer to reduce reflections, or start messing with a stereo arrangement to hopefully recruit the brain into making it sound more realistic. I'll probably try the former first, while saving up for another mic or two for stereo.
RE: PZM Experiments - makinrose - 05-08-2025
I really can't comment on the tone---if it sounds good to you it is good. However, I can hear the strings on the guitar alongside the sound from the speakers on many of the tracks which is a little distracting and can make it hard to really hear the sound from the cabinet. Isolating that out would help the sound a lot. Just a friendly suggestion! Sounds like you are having a good time experimenting...
RE: PZM Experiments - physics - 05-08-2025
(05-08-2025, 12:20 AM)makinrose Wrote: I really can't comment on the tone---if it sounds good to you it is good. However, I can hear the strings on the guitar alongside the sound from the speakers on many of the tracks which is a little distracting and can make it hard to really hear the sound from the cabinet. Isolating that out would help the sound a lot. Just a friendly suggestion! Sounds like you are having a good time experimenting...
Heh, you're not the first to complain. At some point I'll have to figure out the isolation bit, so far I've just been trying to match what I hear in the room. It would be nice not to hear the strings though.
RE: PZM Experiments - physics - 07-23-2025
(05-08-2025, 12:20 AM)makinrose Wrote: I really can't comment on the tone---if it sounds good to you it is good. However, I can hear the strings on the guitar alongside the sound from the speakers on many of the tracks which is a little distracting and can make it hard to really hear the sound from the cabinet. Isolating that out would help the sound a lot. Just a friendly suggestion! Sounds like you are having a good time experimenting...
Revisiting the comment on string noise... I have a reamp box in the mail. I'm getting it to do IRs, but figure it'll also be useful for recording room mics at low volumes without string noise. Will screw around and post results here when I have 'em.
Unrelated, I got a 2nd PZM of the same model so that I can do stereo pair setups. I've toyed with it a bit, and I'm pretty happy with the results. Of course, panning now means physically rotating the mic array and hitting record, but when it sounds so much better and realistic than a 57 who cares. Will have to post some clips when I get a chance. Double-tracking with hard pans by rotation gives a very nice big sound too.
RE: PZM Experiments - physics - 11-25-2025
Been a while since I posted. School 'n stuff has kept me busy. Since last time, in no particular order, I've
- Built a PZM wedge out of plywood according to the Crown Boundary Mic Application Guide.
- Figured out how to flatten the PZM high-frequency rise with EQ.
- Obtained a Fryette PS-100 reamper to blast the Marshall into and then reamp to an apartment-friendly volume or take a DI signal out of.
- Got a Peavey XXX 4x12 to chuck the speakers from and use the cab.
- Recorded a bunch of clips of the same riff using a looper pedal with different permutations of Force 12's, XXX's, microphones, and the 2x12 combo and 4x12 closed back cab.
- Parked the Force 12's in the 4x12 with the two bottom holes empty (detuned).
- Added foam "mitchell donut" beam blockers to the 4x12.
- Worked out how to get a "close mic" recording of the detuned 4x12.
- Screwed around with EQ and master volume levels to get a pretty good (IMO) Marshall tone through said cab.
- Captured a sound very close to that using the PZM wedge with the flattened response.
- Sorta fixed the string bleed issue by virtue of not doing anything and hoping it goes away by itself.
Various bits of all that will probably pop up in other threads at various points, in particular the cab and mic comparisons, but for now here's a clip of that tone I mentioned:
https://soundcloud.com/grrrrr-662986275/maxed-noodle-take72-pzm-wedge/s-VA1UbPJWMsE
My own takeaways:
- String noise is imperceptible unless I'm actively looking for it on a good monitoring setup, and then it's barely perceptible.
- The level of string bleed I did get was with me sitting right next to the cab and mics, less than a meter way, with the volume at a modest apartment-friendly level.
- The recording sounds very close to what I hear in the room. I mean very close. Even more so if I stick my nose to the grill cloth in the way that the PZM wedge shoved against the baffle is emulating.
- The track doesn't sound distant like a room mic recording.
- The stereo image quite closely emulates that of sticking my head where the mics are. Mono is oddly too wide in comparison.
- Subjectively, I think it holds it's own when I compare it to recordings other people have gotten, including those of guitar youtubers with Marshall tones I like.
- The tones I'm comparing to are almost all recorded with a 57, or 57 + something else. I'm not using a 57, but am still able to get tones with similar qualities by tweaking the amp accordingly.
- With appropriate amp tweaks I can get my setup to sound very close to a Vintage 30 4x12 + SM57 setup (comparing to youtube videos). Enough that I don't really feel compelled to get a V30 to get that particular sound. Plus I kinda like my Force 12 + Amp EQ version of it better anyway.
Conclusion: I either have, or am very close to achieving, my ideal of being able to set an amp to sound good in the room and then print that sound to tape no-muss no-fuss no SM57-high-mid-yuck. I also seem to have accidentally gotten very close to my ideal of being able to control the majority of the sound/tone at the amp instead of relying on a mic and highly colored speakers like Celestions.
Alright, what do you guys think? Any critiques, whether they're technical, preference, or otherwise? Sorry for all the bullet points. I promise I'm neither an AI bot nor using an AI bot to write this.