Electrical engineers: is this possible?

[Bad Daddy DeVille]

When I record distorted guitars ---regardless of which amp and/or speaker cabinet I use--- I get a nasty fizzy sound. I can eq it out of the recording, but I'd like to know if there's a way of putting some form of eq between the amp head and the speaker cab. That might also help with a flabby bottom if I could just eq it out before it gets to the speaker.

I know a line-level equalizer wouldn't be appropriate. I think there are some equalizers used in car audio that go between amps and speakers. Also, I assume this might strain the output transformer in a guitar amp. But does anyone know from an engineering standpoint what the reality is here? Or if there's a way to do this safely?

Thanks!

[The Dude]

What kind of amps have you tried? What microphone(s) are you using and/or are you using a direct output rather than a mic? What kind of recording gear? IMO- let's not try to polish the turd. Let's figure out why there is a turd in the first place.

[eschertron]

Back in the day - and I'm not telling my age - recording engineers would fix EQ issues like this by moving the microphone around. Maybe to the side of the amp, or across the room (recordings were made in things called 'studios' back then), but somewhere the recording engineer would find the sweet spot to place the mic. If there was a choice of microphones, then maybe a different mic would be tried. To cure extreme hi-end sizzle, sometimes a fabric of some kind could be draped over the cabinet to help smooth the sound. You might be surprised at what a thin piece of material - or a couple blankets - can do!
In short, there are all sorts of acoustic treatments that can fix a problem that is basically acoustic in nature. If you were gigging, then a compact, easy to apply (and potentially expensive) fix would be desirable. But I'm thinking you can find a no-cost solution for in the recording space that might *look* odd, but will offer a reasonable improvement to the sound.

[Leo_Gnardo]

Fizzy distortion? Plenty of that in overdriven amps/speakers. And you might be "crushing" the console preamp too. Like the John Lennon vocal crushing a mic pre in "Revolution". Dial in some pad, or if there's none on the preamp you may need to use an inline pad on the mic input.

[Enzo]

(This was written before the other posts, but the forum went down briefly and I moved on. That to explain I was not referring to other posts if it seems confused)

Nah, that is not how we do it. If you have EQ, it generally goes in the FX loop or between the preamp out and power amp in.

Car stereo is a different world, and what they might call an EQ might really be an EQ/amplifier combination. In any case, car stereo gear really does not mix well with guitar amp gear.

But first, what microphone are you using? And have you tried others. Have you tried others of the same model, and have you tried other models or brands? You could be overloading the mic. Or your mic may be damaged so there is a little buzzing in the wind ball or something. Likewise the mixer, speakers are loud and your signal could be peaking in the mixer input channel. Especially if it is a digital mixer or computer sound card type mixer. Digital systems will not tolerate going into the red, while old analog systems loved doing that.


And have you considered a speaker direct box? It is connected between speaker and amp, and provides a line out signal to feed to a console. UNlike a preamp out, this includes some of the influence of the speaker, which usually sounds better than the bare signal.

Here are a few:
speaker direct box | Sweetwater.com

And one from Peavey:
Peavey :: SDI Speaker Level Direct Interface

[dai h.]

(there isn't any mention of the gear being used, but) one possible cause is the mic's frequency response ringing from not seeing the (range of) input impedance it wants to see. This can cause a peak in the high frequencies, which means any signal up there will make the mic pre clip and consequently the sound will be poorer than it should be. Probably the easiest fix is to add a resistor to reduce the impedance the mic sees. This will be at the cost of some mic signal (worse for sig to noise ratio), but probably won't matter if the source is a loud gtr. speaker(amp). Also, I've seen a DIY project (originally from a German magazine) to build a small network consising of two inductors and a cap (10mH, 47nF IIRC) to damp the ringing. This should be better in terms of maintaining the signal level out of the mic. (If memory serves) it was recommended to use w/Shure SM57/58 into input impedances of 5k and up (back somewhere around the 70s? or so, typical mic input impedances seemed to be lower than today, around 1kohm). Generally a higher impedance is better for retaining signal but can cause problems (like underdamping of a dynamic mic and interacting and causing ringing with the RF filter bits at the output of a microphone). I have no idea if this is the source (or one part of) the problem, but (from my reading) I kind of suspect it could be common.

[Bad Daddy DeVille]

Thanks for getting back to me, everybody.

I've used my Vox AC4C1 amp and my Marshall Haze 15. I've used an SM57, SM58, Rode NT1 and an MXL 991. For speakers, I've tried a Vox VX12, Eminence Heritage 12, Warehouse Veteran 30, a monstrous ElectroVoice 12L Series II, and a 10" Celestion Greenback. I bought a highly-touted Radial JDX Amplifier DI box --which supposedly interacts with the speaker-- and that too sounded fizzy when I played distorted power chords. (Aside from the fizz, it just didn't sound good at all, and is going on eBay.)

I've had the mics up against the grille cloth, back about 5", pointed at the dust cap, at the edge of the dust cap, toward the edge of the speaker cone, and pointed at a 45° angle away from the speaker.

Some speakers were even more fizzy than others. Surprisingly, the ElectroVoice 12L Series II was the worst.

The mic is going into an Onxy BlackJack interface which has A/D converters to get the signal into my computer. I have the gain set pretty low, so there's no digital clipping/distortion.

Thinking it was just my lack of worthiness as a recordist, I took both the Vox AC4C1 and the Marshall and the best sounding of all my cabinets up to a recording studio in Boston--- Woolly Mammoth Sound. Between vocal takes by my wife on our album project, I asked our producer/engineer Dave Minehan to mic them up in his amp room. His results were identical to mine in my home studio.

I have a Tech21 Oxford amp simulator coming, and just to be thorough, I'll give that a try, though I've never heard an amp sim that actually sounded like a tube amp's breakup.

The best fix I've been able to come up with is to record my distorted guitar parts, then, in LogicX, I can assign a cab simulation to the track. It changes the character of the amp's sound, but by fooling with the type of cabinet and type and placement of the simulated mic, I'm able to reduce the brash fizzy sound. My other last-ditch fix is when I record my parts, to split my guitar's signal with a Radial AB box I bought and send one to the amp and the other direct to LogicX. I can take both tracks up to Woolly Mammoth and, if the amp track isn't usable, we can re-amp the dry track.

Naturally, though, I'd prefer to be able to get a good sound here in my home studio! It seems like everybody in the world except me can just jam a 57 up against their speaker cabinet's grille cloth and get a decent sound. I'm determined to get this, though. As I mentioned, I'm recording an album with my wife and I want my guitar to sound right.

Here's the sound I'm getting out of the Marshall Haze 15:
http://hallamgallery.com/Jack/Marshall.mp3

I bought a Vox AC15C1 that just arrived today, and gave that a try through its internal Celestion Greenback 12:
http://hallamgallery.com/Jack/VoxAC15.mp3

[The Dude]

Doesn't sound all that hideous to me, but then right now all I have available is a some smaller bookshelf speakers (at work). It's a bit hard to tell because the samples are just a chord. I'd need to hear something with more picking to have a better idea of what you're hearing. Have you tried just rolling off some high end (5K and up)? The Marshall definitely sounds meatier.

[Bad Daddy DeVille]

Now my Marshall head isn't working! I plugged it in, connected a cab, plugged in my guitar... and nothin'! There's no hiss going to the cabinet, so it's not like it's a faulty guitar cord or something. When I flick the channel switch, I hear a little click out of the speaker, so there's ~some~ activity going on.

Man, I swear... I'll take it apart tomorrow and see if I can see something obvious in there.

[dai h.]

also, the cable capacitance the gtr pickup sees affects the resonant peak (from the pickup), so playing with the amount of capacitance can move the peak and affect the perceived harshness (that is if the peak is moved to the frequencies the ear perceives as harsh things could sound worse for the distortion (but could be good for clean)). Also, (my understanding is) that it's normal practice to apply a LFP(hi-cut) to a recorded gtr. signal to tame some of the fizz.

[Enzo]

OK, you already ate the low-hanging fruit, so to speak. You took the problem to a pro recorder, and he got the same results. That tells me you really are not doing anything wrong. it tells me there is a part of reality you don;t like, and like putting on sunglasses on a bright sunny day, you have to do one of the things you have been doing to cure it.

Is this something that only shows up on recordings, or can you ever hear it live WHILE recording?

[Chuck H]

I think a very relevant question at this point is... Do you get a guitar tone your happy with prior to attempting to record it? Do you have any band or recording experience that might lend itself to how guitars play within the mix? There is no magic button to push that says "good guitar tone from bad guitar tone" for recording purposes. $h!t in = $h!t out!!! The mic hardly matters WRT guitar recording because any self respecting mic has a reproduction response far beyond the range covered by guitars and their amps. With a nod to eschertron for mentioning experimentation to mic placement and general experimentation. But a bad tone is a bad tone and will always be a bad tone. The exception being that a great musician could probably find something musical to exploit in almost any tone (thanks Stan (KM6Xz). So the paramount question is, are you having trouble recording what you believe to be a good tone or are you having trouble getting a good tone in the first place before you try to record?

[eschertron]

I listened to the sound clips, and to me they sound about like what I'd expect from a mic jammed into the grill cloth. If the internet or a recording engineer has led you to believe that you won't have to process the recording to get it to sound more 'natural', then forget that notion. If the recording equipment catalogs, trade publications, websites, and prior experience have given me a clue, it's that there's an entire industry built around software simulation and modeling of amps, cabs, rooms, and natural ambiences. You *must* add the acoustic space back to any close-mic'd sound. The old-school way is with EQ and reverb. Today's state of the art uses plugins with your DAW. My comments above were to get you to experiment. That's the real genius of recording!

If you like the way the amp/cab/room sounds to you while you're playing, then mic the 'actual sound' of your playing from that vantage point. If you like the tone that you hear, then record that - from the vantage point of where your ears tell you it sounds good - instead of an arbitrary point in front of the amp grill. If you must close mic, know that many recording engineers are known to be extremely fussy about where they place the mic even in front of the cabinet. Inches matter.

[Bad Daddy DeVille]

Hi. Thanks to everyone who chimed in on this thread, helping me as I struggled to get a recorded guitar sound I liked. I tried a number of different direct boxes, different amps, different overdrive stomp boxes, and a zillion different speakers. I just wanted to come back here and announce that I ~finally~ nailed it! On my last stomp box binge, I saw that there was a cheap solid state amp with a 12ax7 in it---that cost less than some overdrive pedals. Since I was abusing my credit card anyway, I bought it on a whim: the Orange Micro Terror, for a hundred and fifty bucks.

Well, I plugged it in and... I'd found my holy grail of tone! Seriously! Fat, warm crunchy distortion with no fizz, no buzzy rattle. It did well with all the speakers I had, but the best is with the ElectroVoice 12L, using a small condenser mic pointed a little off the speaker cone at about 5" distance. Here are a couple of clips of the sound I'm getting. (Strat pickup in the neck position for the chords, Giovanni EVH-2 for the lead stuff):

http://hallamgallery.com/Jack/guitarA.mp3

and

http://hallamgallery.com/Jack/guitarB.mp3

And here are those tracks in a rough mix with other instruments, so you can hear context. This is a shortened version of a tune I'm working on:

http://hallamgallery.com/Jack/Shorte...mbie Swamp.mp3

The guitar now sounds like what I hear in my head. Whew! Now I can get on with tracking my songs. Thanks again for all the help, everyone.

[jazbo8]

Very nice! But I had to ask - is the change purely due to the MT? To me, the previously cliips besides sounding a bit fizzy, over-distorted, they seem to be recorded "hot" and the MT clips seem to be recorded at the right level... In any case, I have more respect for the MT now, it always sounded "one-dimensional" when I demo'd it before.