#1
Hey everyone,

I'm having issues trying to record my amp. I have one of the knock off SM57's by TBone and it seems OK for the price, and I'm running it into a Fostex MR8 MKII into the XLR input. I have to crank the guitar amp really loud to get a decent signal from it, which is a pain as I'm living in a flat. I'm not after spectacular recordings which is why I'm only using a cheap mic, I'm more just putting out feelers and getting an idea for the whole thing.

Do I need a mic preamp to increase the signal? If so any cheap ones recommended? When the amp is cranked the recording quality is (to my ears) pretty passable, for a bedroom project.
#2
Is there a mic gain control on that interface? I use an sm57 with a UX1 and have to turn the mic gain up a bit if I recording lower volumes, I also turn on the 18db boost with pod farm aswell that helps a nice amount.
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#4
Hi,

I'm using sm57 as well, it's just fine for clean tones. What stuff do you play?
I have no experience with the fostex but i believe it has builtin mic preamps (correct me if i'm wrong). If it comes to dynamic mics - yes, it's always necessary to turn the volume up. Especially if you want to place the mic further from the speaker.
But, do you have any option to mixe the line out with the mic? That would make the sound "fatter", and having the mic override the line signal would let the latter fill the space.

And answering the question about the mic preamp - i use focusrite saffire interface, and yes - the mic preamps are helpful.

PS. I can share a sample recorded with a sm57 with the volume at 0,5 (sic) of a 120W laney amp.

EDIT:
Ok, i get it - fostex has guitar preamps but not mic ones.
What about changing a mic cable then? To a jack one. It's not a condenser mic, so you do not need a phantom power. Or have you tried it and it is not satisfactory?
Last edited by zywiec at Jul 27, 2011,
#5
Hi zywiec,

Thanks for your reply, I appreciate it. To answer your question I am using an xlr cable, my mate has the sm58 knock off and he uses a xlr to instrument jack cable, and the level was defiently much better,well we recorded some vocals and the level was fine. I haven't tried it for the amp though. I ordered a cheapy behringer preamp so I'll see if that helps, if not do you think a cable change would help?
#6
I did not mean the sole cable change. Using XLR going to an input without the preamp seems less reasonable than using the same mic with a jack cable going to the input with guitar preamp. At least, you should gain the "gain", and use some eq to create suitable sound. I do not know the specs of your equipment, but as i said - this mic does not need a phantom, so you can use a jack cable with it and connect it to a different input.

I do not know if it will make it better or worse, yet you can try.
Anyway - i use sm57, but the SHURE sm57. But i do not think the name of the producer will might have made it that different. change the cable and try going through a guitar preamp (with little gain it should not behave as ordinary instrument line in).

Moreover, you wrote: "the sm58 knock off and he uses a xlr to instrument jack cable, and the level was defiently much better,well we recorded some vocals and the level was fine". Did you plug that sm58 to the same fostex but the line with the guitar preamp?
Last edited by zywiec at Jul 27, 2011,
#7
it looks like the trim control is essentially the gain control. so if youve got that cranked up and dont have enough signal strength, a mic preamp might be a good option. nice thing is, you can get something decent for pretty cheap. Example here. it isnt going to sound super awesome, but it isnt going to kill your quality either.
#8
Quote by jof1029
it looks like the *trim* control is essentially the gain control


Strange thing. since...:

Quote by jof1029

. so if youve got that cranked up and dont have enough signal strength, a mic preamp might be a good option.


what do you want to trim? The input singal from a mic? I'll never unedrstand this if it's not related to the triming of a loudspeaker outlet.

Quote by jof1029

nice thing is, you can get something decent for pretty cheap.


like with any other stuff. The point is, that he seems to use the worst option possible against the equipment he can already use.
Of course, additional stuff will help, but it's always better to find out what you can do with things you have, before incorporating new ones (possibly incompatible).
Sometimes it's cheaper to replace the wrong fundamentals, then to replace the roof over and over.
#9
i actually googled the thing and found the manual, this is what it says about the knob:
[TRIM] controls
Control the input gain of the [INPUT A] and [INPUT B] sections (see page 30).


its just called something strange, but it is a gain knob. if he has the gain all the way up and the signal strength is still too low, an external preamp is a solid option.
#10
Quote by jof1029
i
its just called something strange, but it is a gain knob. if he has the gain all the way up and the signal strength is still too low.


Yes, once again - i'm not native, but if you "trim" - you trim the signal. In my mixer - if i trim the input signal (of the already processed one), i can "amplify" it ("gain") without the clips (but with the narrowed dynamics).
#11
Quote by jof1029
if he has the gain all the way up and the signal strength is still too low,


then he should hear some noises and crackling. And... he should tell us to stop guessing :-)
#12
Quote by zywiec
Yes, once again - i'm not native, but if you "trim" - you trim the signal. In my mixer - if i trim the input signal (of the already processed one), i can "amplify" it ("gain") without the clips (but with the narrowed dynamics).

i would agree that the knob is poorly named. trim means to reduce volume and gain would be to increase when i usually look at things. i just know that lots of companies come up with strange names for things
#13
Quote by jof1029
i would agree that the knob is poorly named. trim means to reduce volume and gain would be to increase when i usually look at things. i just know that lots of companies come up with strange names for things


You mean they're named opposite to what they do? I trim the signal, and gain the volume of power (make the output from the amp stronger). If i was to preamp something just to trim it afterwards.. then what would i actually "gain"? A "volume"?
Ok, i have no arguments now, it's 3am for us living in CEST. :-) Cheers, and have fun experimenting. :-)

EDIT: Jof1029 - do you have experience in using DI BOXes? I'd appreciate any thoughts (separate thread of mine).
Last edited by zywiec at Jul 27, 2011,
#14
Not to be a pedantic arse but you're actually both wrong In an amplifier, you do not 'add gain' - gain is always fixed, you simply attenuate how much signal is sent through the amplifier section, to achieve the final output level. So technically a trim pot is probably the better name of the two, or at least the most accurate (for example, in old-school consoles, the preamps and power amps all had a fixed turns ratio in the output transformers... you aren't adding any gain by pushing the fader up/turning the 'gain knob' clockwise; you're reducing the amount of attenuation, through resistance, to the flow of signal through the transformer).
Hey, look. Sigs are back.
Last edited by DisarmGoliath at Jul 27, 2011,
#15
"input" "trim" "gain" "head amp" "pre" and a few others all can mean the same thing. If you see a knob at the top of the channel strip or right below the input, chances are it's the gain knob.
#16
Wow, a whole lot to read through here this morning (I'm in th UK) . Thanks to everyone for their responses. My mates 58 knock off (using the XLR to instrument jack) was much more audible without any guitar preamp being used, I did have the trim up a bit, maybe 2 o'clock, but I got a decent level. Even with the trim right up when using my 57 knock off and an xlr-xlr cable the level was unacceptably low. Now if I crank the volume on my amp to a really high volume I can get an OKish level, but I still have to have the trim turned up pretty high. I have a cheapy behringer mic preamp on the way, so I'll give it a go later on and let you guys know how it turns out. Tjhanks for all your help!
#17
Quote by DisarmGoliath
Not to be a pedantic arse but you're actually both wrong In an amplifier, you do not 'add gain' - gain is always fixed, you simply attenuate how much signal is sent through the amplifier section, to achieve the final output level.

while this is true, the gain knob still controls the ammount of gain from one stage to the next. a passive component such as a knob can never increase signal strength, only decrease it. but i would argue that there are two ways to look at what the knob does. one being exactly what you said, it takes the output of a gain stage and decreases it from the maximum, or trimming it. the other is to look at what the knob does in a larger context as a controller for the gain stage. when you look at it that way, the knob is controlling the level of gain the input of the stage to the output, even if it itself is not adding gain.

at the end of the day, its just semantics. and thinking about the knob from both the electrical standpoint and the control standpoint is better than just one or the other.