'Purr' in a guitar tone

[drb]

One of my favourite sounds in high gain guitar is the purr, that oscillating sound that brings tonnes of texture. It's usually noticeable in a soft, blooming palm mute and pretty much exclusively in lower notes (in my experience). However, it isn't always there, some guitar tones have lots of it and some have barely any.

I currently have 2 physical amps - MT15 and a 5150iii 50W stealth. The MT15 is purr central, I can plug any guitar in and it will have that purr like crazy, I love it. The stealth, on the other hand, is quite hard to get that quality on the red channel, where as the blue channel boosted is almost as good as the MT15.

What do you all think? Is this something you like and aim for? Not really thought about at all? Maybe even avoid it?

Also does anyone know what it actually is, such as what is sonically or physically going on, and what causes it? I imagine it's something to how the gain is structured in an amp but I could be wildly off.

Also 2: feel free to post good examples of it in your own recordings or music you like. One of my favourite, relatively recent examples is the main/intro riff here:

 

[Spaced Out Ace]

It is probably some sort of resonance in the low end (bass or low mid frequencies).

 

[Chri]

It’s definitely something I look for in my “go-to, jack of all trades” metal tones. I’ve just found that if I can cop a good tone with that on the palm mutes, it’ll get on with just about everything. Unless I’m going for some super specific, niche death metal or black metal tones, the “purr” is where it’s at.

That said, I have no clue what causes it. It’s kinda like the forbidden D word onomatopoeia. If it’s there, you know it. If it’s not, you also know

’d on my speculation though. I’ve always felt that amps that have very present low mids do this best.

 

[thebeesknees22]

i'm guessing synths layered in. Or somethin'. But I dunno.

 

[Emperoff]

I don't know man, I have two cats and can't hear any of it in that video you posted

 

[drb]

i'm guessing synths layered in. Or somethin'. But I dunno.

But I can replicate it of sorts on some amp channels sans synth. I imagine when it's really prominent in produced records there is some synth in there though.

I don't know man, I have two cats and can't hear any of it in that video you posted

Yeah to be fair, none of my cats sound like that now I think about it hahaha

 

[wheresthefbomb]

To me, the 'purr' is what separates good and great doom/sludge/post metal tones. For example at 3:29 in this song. YONL has three guitarists, two bassists, and a keyboard player in addition to two drummers, so that plus experience suggests that it has a lot to do with the layering.



That said, RAT boosting a Pharaoh (or any fuzz) into a high headroom amp goes a lot of the way toward that sound. Also, to me, the textures that come from cranking a SS power section have that purr as well. It's when the note goes "dooOOOOoooOOOooooOOOooommmmm"

 

[Gudbrand]

I've never heard it called that, but I immediately knew what you meant. It's most associated with doom metal in my mind.

I'm not sure what causes it, but I'd like to figure it out. I wouldn't associate it specifically with solid state amps. More with volume, and boosted mids.

 

[drb]

To me, the 'purr' is what separates good and great doom/sludge/post metal tones. For example at 3:29 in this song. YONL has three guitarists, two bassists, and a keyboard player in addition to two drummers, so that plus experience suggests that it has a lot to do with the layering.



That said, RAT boosting a Pharaoh (or any fuzz) into a high headroom amp goes a lot of the way toward that sound. Also, to me, the textures that come from cranking a SS power section have that purr as well. It's when the note goes "dooOOOOoooOOOooooOOOooommmmm"

That is a really good example, exactly what I mean. I might have to try and replicate this on my HX Stomp as I've never gotten into doom (might have to now though) so I don't have the physical gear for it.

I've never heard it called that, but I immediately knew what you meant. It's most associated with doom metal in my mind.

I'm not sure what causes it, but I'd like to figure it out. I wouldn't associate it specifically with solid state amps. More with volume, and boosted mids.

Honestly I'm not sure it's the correct word but it definitely makes sense. I saw on the Misha Mansoor signature plugin he had ages ago that one of the options was purr and that's what I guessed it meant.

I was either associating it with mids (low mids, like Tree and Spaced Out Ace said) and maybe gain structure?

 

[Crungy]

@drb your example makes me think og August Burns Red's White Washed near the beginning.

 

[drb]

@drb your example makes me think og August Burns Red's White Washed near the beginning.

Yes! That's an absolute banger and totally nails what I'm talking about.

 

[wheresthefbomb]

I'm not sure what causes it, but I'd like to figure it out. I wouldn't associate it specifically with solid state amps. More with volume, and boosted mids.

I would agree, cranking a SS power section is just one of the more reliable ways I've found to get it. Tube amps sometimes seem to almost have too much headroom to do the thing before they just get mushy.

Another part of the formula for me personally seems to be multiple dirt stages at relatively low gain/high volume.

Overall I think it's a balance of high headroom, power amp breakup, and just the right amount of dirt in the right spots. I have very little experience dialing this kind of sound from amp distortion so I'm sure it's a little different.

 

[Chri]

That is a really good example, exactly what I mean. I might have to try and replicate this on my HX Stomp as I've never gotten into doom (might have to now though) so I don't have the physical gear for it.

Honestly I'm not sure it's the correct word but it definitely makes sense. I saw on the Misha Mansoor signature plugin he had ages ago that one of the options was purr and that's what I guessed it meant.

I was either associating it with mids (low mids, like Tree and Spaced Out Ace said) and maybe gain structure?

Now that you mention it, it definitely is a Misha-ism. I don’t think I had ever heard it referred to that way prior to him demoing the Axe II or something like that back in the day and it just stuck with me.

Since you’re an HX user I assume you’ve been using the new Invective model, right? If not, get on it! It does this better than anything else in there IME. Especially with the Plumes OD in front.

 

[drb]

Now that you mention it, it definitely is a Misha-ism. I don’t think I had ever heard it referred to that way prior to him demoing the Axe II or something like that back in the day and it just stuck with me.

Since you’re an HX user I assume you’ve been using the new Invective model, right? If not, get on it! It does this better than anything else in there IME. Especially with the Plumes OD in front.

Oh yes I am very much on the Invective model, it is sensational. Even more so with the Plumes OD like you say. I had found that it does the purr very well, maybe someone at Line6 could explain what causes it since they've modelled it!

 

[ElRay]

I don't know man, I have two cats and can't hear any of it in that video you posted

You need an extended range, 12-wisker cat. Remember, "baritone cat" refers to a feline pitch range, not a length.

 

[Crungy]

Totally a Misha-ism, there's a purr knob on his JST plugin lol

 

[Matt08642]

I'm pretty sure it's just low end resonance?

 

[MoJoToJo]

Orange Crush Pro Bratwurst Fuzz
https://logamp.com/10967/music/tracks/41483

 

[ExMachina]

Sounds like an amplitude modulation due to something going in and out phase. Total silly wild ass guess could be accentuated VSWR due to impedance mismatch from the speaker and power transformer. But I'm not sure if that's a thing as much outside of RF.

Try this as an experiment, use two cabs and adjust the phase so they are slightly off. Play around with how out of phase they are and see if it sounds like this.

 

[Sylim]

oh yeah, i love that purr sound. the perfect subject were you know exactly what you want to say, but lack the words for it so you have resort to weird adjectives i think it´s basically what you said, light palm mute, good low mid focused amp. i´d add pre amp boost so it´s not muddy, good tuning and also pickups matter. they need to have a decent sounding push/pressure/compression, be very focused and pronounced in the low end and mid range instead of smooth and flat and they need to handle low tunings well. i´m sure a Seymour Duncan JB will have a harder time than a Custom 5. i got Blackouts in my 7 string and it´s a total beast. they naturally have more of a dooooh tone than a deeeeeh tone. so that purr is much easier to get with them.

as to what happens exactly on a physical level, i´m not sure. i imagine it´s everything working together in a way that the distortion of the amp doesn´t end up just smooshing everything, but rather accentuates the low fundamental and lower harmonics.