SM58 Issue

[mancini120]

I recently purchased a Shure SM58 Microphone and a U-PHORIA UMC22 USB Interface from a known professional retailer and connected the mic via XLR cable. I've been testing it out and the only way I can get a signal is if the gain is set to 80% or higher. Could someone help me out?

 

[drtechno]

That is actually typical for that mic pre on a lowz dynamic. The U-PHORIA mic pre are like the scarletts, they will pass with some, but a real mic pre works better. 3K ohm for a terminating impedance would be more suitable for line in uses than mic connections. A modern condensor mic (like an AT2020 or even one of those $30 mics off ebay) is mid impedance (1K-3K) which would work for that $3 mic pre.

 

[CoolCat]

drtechno's right...what the 58 and most the dynamics of that type need is more gain or a loud source (guitar cabinet).
If youre doing 58mic on a soft quiet source, acoustic or low volume source it might not be the best match.

to fix this people have options.
1) get a mic preamp with 60db+ of gain
2) try a Condensor LDC mic for example, that is more sensitive and captures the softer sources better.
3) bump up the volume if you can with the DAW plugin-preamps etc..

1) a bunch of used gear from decades of HR is available pretty cheap.
2)Ive found mics with 14mv/pa in the spec works well with the weaker interface pre's and are also not too sensitive for picking up too much room and noises.KSM27 for example,14mv/pa spec LDC, great mic.... theres an ocean of the mics too many to comprehend. Your interface has the phantom 48V for those mics, reading review your interface has a good Phantom power too.
3) if you have plugs those can add the digital gain ITB.

I have a USB powered interface same issue, mic pre is only +20DB, a SM58 likes about 60db power. I couldnt find the spec on the UMC22?

 

[gianluca68]

The SM58 is a dynamic microphone, then it requires a high gain. They are firstly designed for singing, then working with high acoustic pressure levels and giving not so low electric signals. If you use a SM58 for low level sounds, you need a very silent preamp to avoid hissing.

 

[Mack Caster]

I recently purchased a Shure SM58 Microphone and a U-PHORIA UMC22 USB Interface from a known professional retailer and connected the mic via XLR cable. I've been testing it out and the only way I can get a signal is if the gain is set to 80% or higher. Could someone help me out?

I use several SM 58s as well as the 57s. Your set up should work just fine. You want your inputs signal to be between a -12dbs and -18dbs. If you can reach these levels at 80% gain, rock on. You will use your DAW to boost the final output dbs.

If it is for music it would be between a -9 and -13dbs, if it is for Podcasting and you follow the AES, it would be between a -16 and -20LUFS. If you follow the ACX requirements for audio books, it would be between a -18dbs and -23dbs using the RMS loudness measuring system. Can you supply a little sound clip?

 

[arcaxis]

Are you 'kissing' the grill (or at least fairly close) when you speak/sing or two feet (60cm) away from it? Live mic like the SM58 is intended to be used pretty close to the mouth.

 

[ecc83]

Are you 'kissing' the grill (or at least fairly close) when you speak/sing or two feet (60cm) away from it? Live mic like the SM58 is intended to be used pretty close to the mouth.

+1 and there is no direct relationship between the input impedance* of a mic pre amp and its gain or noise performance. 3 k Ohms is far too low for a line input and could cause distortion on some sources. (many an old cassette deck was specc'ed into 10k or higher)

Mancini, can you do a 'silent' recording with the Uphoria? Run the mic pres with nothing connected at max gain then at minimum. This will give an idea of how useful the AI is for dynamic mics . Post results as a 320k MP3 attachment please.

*Should really be called input 'resistance' since it would be an odd amplifier whose input load varied with frequency. BUT! We is stuck with 'impedance' I guess!

Dave.

 

[Mack Caster]

Here is my SM 57 with around 20dbs of gain. The 57 and 58 are identical except for the head. The 58 is round like a ball and the 57 is more narrow. It was run through my Alesis Mixer. It has a max of 30dbs of gain I believe. It was a test for my track room before any sound treatment was added. The first part of the clip was about 2 inches from my mouth, the second part was with a light fleece jacket over my head kinda like a sound booth type of thing and the third part of the clip was with the mic around 10 to 12 inches from my grill, out in the open.

 

[rob aylestone]

Please let's not start the old 57 vs 58 are the same bar the windscreen rubbish. They are different. Shure say they are different capsules. Shure say they have different frequency responses. Surely (sorry) that's enough.

The people who know are saying the same thing here - dynamic mics designed to be used close in don't need as much gain compared to when you use them at a distance. Simple USB interfaces just aren't good enough if you need lots of gain. Decent preamps cost real money, and you get good performance. How much is the interface we're talking about here? Hmmmmmm.

Why do we constantly expect cheap and simple to be good and effective? It's not the microphone's fault!

 

[Bobbsy]

I'm old enough to recall when the capsules in the 57 and 58 were identical (same Shure part number) but they were changed to be slightly different quite a few years ago. However, the change is mainly to do with how they mount in the mic case/screens. The capsules are still based on the same design and spec.

The big difference is obviously the grill design. The big ball on the 58 functions as a pop filter and allows the mic to be used for close up vocals in a loud environment. The 57, on the other hand, is designed for instrument miking and has a far simpler grill to let the mic get close in. This difference also means that the 57 has a bit more proximity effect, changing the frequency response somewhat.

There are more details on the Shure site HERE.

However, none of that changes the fact that both mics are designed for close up work on loud sources--and need a mic pre amp with lots of clean gain. They're far from ideal "all purpose" mics.

 

[Mack Caster]

I'm old enough to recall when the capsules in the 57 and 58 were identical (same Shure part number) but they were changed to be slightly different quite a few years ago. However, the change is mainly to do with how they mount in the mic case/screens. The capsules are still based on the same design and spec.

I remember the same. I don't argue with people anymore, it ain't worth the effort on something that is written in stone. Thanks for proving the link, you saved me some time. I always recommend the 57 for Podcasting. It really helps reduce the BG noise as most Podcasters don't do any room treatment.

 

[Mack Caster]

Please let's not start the old 57 vs 58 are the same bar the windscreen rubbish. They are different. Shure say they are different capsules. Shure say they have different frequency responses. Surely (sorry) that's enough.

The people who know are saying the same thing here - dynamic mics designed to be used close in don't need as much gain compared to when you use them at a distance. Simple USB interfaces just aren't good enough if you need lots of gain. Decent preamps cost real money, and you get good performance. How much is the interface we're talking about here? Hmmmmmm.

Why do we constantly expect cheap and simple to be good and effective? It's not the microphone's fault!

Alesis has a 4 channel USB Interface for $99.00. Works like a champ! 30dbs of nice clean gain.

 

[Mack Caster]

Mancini, can you do a 'silent' recording with the Uphoria? Run the mic pres with nothing connected at max gain then at minimum. This will give an idea of how useful the AI is for dynamic mics . Post results as a 320k MP3 attachment please.
Dave.

Hey Dave, would you do this for me as well. I would be very grateful as well as understanding how you can use this file to make your conclusions.

EDIT: Hey Dave, I still have no idea how you come to your conclusions, but you got me to thinking. Believe it or not, that don't happen often. So this is what I did. I followed your advice with about 8 secs at no gain, 8 sec with full gain and the mains out control set to 00, then 8 sec with all the gains wide open. I rendered the file as you suggested and then placed the freq analyzer on that track. The first two recordings showed no change but the last recording with all the gains wide open, showed around a +30db boost. The noise floor for the first two was around a -86dbs and the last jumped to around a -56dbs. Am I close or way off base? If nothing else, it does show the Alesis with 30dbs of gain. Anyway, here is the file if you have time.

View attachment 100471

 

[ecc83]

Morning Mack, always glad to get peeps thinking!

I am actually not sure what you want me to do? Silent recording yes, but with which AI and on what DAW?

My post about a silent recording was actually aimed at the OP in order to establish a noise floor for his system.

Anyhoos, YOUR clip...
Starts at -71dBFS peak*/ -82.6 rms then jumps to -47.6 peak -70.0 rms. Not in the Prism range by any means but decent enough I would say for a singer right onto a 58. This was the Alesis what?

The Right Mark anny shows a total lack of 'spikes' VERY commendable for a USB device. I cannot explain the low end roll off, a consequence of MP3 to .wav conversion? (R Mark can only handle 16 bit .wav. HR attachments can't!)

*Figures from Samplitude SE8 which has a meter range to -90dBFS but also gives a numerical readout below that.

Re the 57/58 debacle? The 57 need a pop shield. Found that out a few weeks ago doing an A/B test with another mic.

Dave.

 

[Mack Caster]

@ecc83 . Thanks Dave. It was the Alesis Multimix 8 USB FX. I also have the Alesis Multimix 4 USB FX and it reads just the same. The reason for the low end roll off was I had the "Lo Cut" button engaged. The pic below shows doing the same process with the lo cut off.

EDIT: I also should have mentioned that if I use it for the sm57, 58 or the atr 2100, the main gain control is set at 12 o'clock, then fader gain control is around the 10 o'clock and the master out control is set at around the 1 o'clock position. This will but my input signal between the -12 and -18dbs range.
I do not think it would run a mic like the Shure SM7B though. If I remember correctly they need something like a min of 60dbs of gain.

View attachment 100483

 

[ecc83]

[MENTION=89697]ecc83[/MENTION]. Thanks Dave. It was the Alesis Multimix 8 USB FX. I also have the Alesis Multimix 4 USB FX and it reads just the same. The reason for the low end roll off was I had the "Lo Cut" button engaged. The pic below shows doing the same process with the lo cut off.

View attachment 100483

Gotcha!

It has occurred to this old brain that I have been chucking out spectra here with no reference and that some peeps might think I have a $10,000 super system! Not so, the best noise floor is given by the KA6 at min gain and is about -103 dBFS. My 2496 in a desktop just beats -98dBFS but with a 50Hz 6dB blip that defies detection. No matter, those noise floors are more than good enough for any real world music work (and of course would be worsened for 16bit CD)

Attached is a plot of white noise at precisely -18dBFS peak in Samplitude and it shows that RMAnalyser 'improves' the noise floor by some 42dB!
I guess there IS a way to calibrate it but in truth I just use it for spotting hums and other nasties, mostly in forumite's clips since I have no musician here any more.

Dave.

 

[Mack Caster]

Gotcha!

It has occurred to this old brain that I have been chucking out spectra here with no reference and that some peeps might think I have a $10,000 super system! Not so, the best noise floor is given by the KA6 at min gain and is about -103 dBFS. My 2496 in a desktop just beats -98dBFS but with a 50Hz 6dB blip that defies detection. No matter, those noise floors are more than good enough for any real world music work (and of course would be worsened for 16bit CD)

Attached is a plot of white noise at precisely -18dBFS peak in Samplitude and it shows that RMAnalyser 'improves' the noise floor by some 42dB!
I guess there IS a way to calibrate it but in truth I just use it for spotting hums and other nasties, mostly in forumite's clips since I have no musician here any more.

Dave.

Very good to know Dave. THANKS for the OJT.

 

[Stompanoogie]

Check your Z. I had the same problem. Fortunately, I can change the impedance on my interface to match whatever is coming in. When I am recording guitar or keyboards, I have to switch the Z on the interface from where it was when I was recording vocals. You just have to play around with things to find out what works.

 

[CoolCat]

Check your Z. I had the same problem. Fortunately, I can change the impedance on my interface to match whatever is coming in. When I am recording guitar or keyboards, I have to switch the Z on the interface from where it was when I was recording vocals. You just have to play around with things to find out what works.

Thats a nice option, would that be a Audient interface?

I see this ASP880 has a Hi, Med, Low switch.....it would be interesting to hear what that does.
I read once the impedance can really affect a 57, Ive never really tested that comment.

clip:
The input impedance is controlled, as before, from a recessed toggle switch, but the markings now refer only to 'lo', 'hi' and 'med'. The values are quoted as 200Ω, 3.6kΩ and 1.4kΩ, respectively, which is another change: the previous model provided 200Ω, 5kΩ and 1.2kΩ. The input‑impedance switch affects both the mic and line inputs, and alters the input sensitivity to a degree which is dependent on the source impedance. Changing the input impedance alters the way the microphone capsule is loaded electrically, and can bring about substantial tonal differences in dynamic mics and capacitor mics with output transformers. With a line input, the impedance switch really only changes the level: with a nominal 100Ω line source, switching from high to medium impedance reduced the input level by 5dB; the low impedance option knocked it back by 20dB. The published specifications claim the line input impedance is over 10kΩ, but I measured values of between 6 and 8.5 kΩ. For the mic input, I measured values of 220Ω, 2.8kΩ and 1.3kΩ. Engaging the pad didn't appear to change the impedance significantly.

 

[gianluca68]

A dynamic mic has a low internal impedance, then it can work well even with a low-impedance input device such as 3kohm. Lower impedances (=resistances, because modern transformerless preamps have a pure resistive input impedance) will affect mostly low frequency response, because it will act as a load, a brake for the generator (the coil in the magnetic field).
Many mixers have mic input impedance between 3 and 5 kohm, because it lowers input noise.