Using An Attenuator

[BillyBoy]

A friend went to a Neil Diamond concert in Manchester UK the other night.. with a NetMd.. I advised her to set the MD at (mic = Low sens)... RecSet at (Manual.. about 50%) She used the UK version of the attenuator connected and set at full volume.. She placed the MD and Mic on the floor in front of her..

The result was that the volume was so low it was almost useless.. Although I was able to pump up the volume in Audition.. I had to pump it up so much that the quality was poor and it introduced unwanted artifacts..

She is going to some more concerts over the next week.. could someone please offer some advice on how to do better.. Should she get rid of the attenuator.. alter the mic sens settings... set the manual rec level higher?...

Any advice would be very much appreciated..

[greenmachine]

3 potential faults i can think of:

a.) she used line-in instead of mic-in by mistake

b.) she set the attenuator to minimum instead of maximum volume by mistake

c.) she set the attenuator to minimum and used line-in

I wouldn't get rid of the attenuator in loud situations, unless you want to try the directly to line-in setup.

Edited May 23, 2005 by greenmachine

[BillyBoy]

3 potential faults i can think of:

a.) she used line-in instead of mic-in by mistake

b.) she set the attenuator to minimum instead of maximum volume by mistake

c.) she set the attenuator to minimum and used line-in

I wouldn't get rid of the attenuator in loud situations, unless you want to try the directly to line-in setup.

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Thanks for your suggestions..

She assures me that she used the mic-in

The attenuator was set to maximum

It's a mystery.. ain't it?..

[greenmachine]

d.) she confused headphone and microphone jacks, plugged the mic with the attenuator to headphone out, the headphones to mic-in and thus recorded through headphones

[BillyBoy]

d.) she confused headphone and microphone jacks, plugged the mic with the attenuator to headphone out, the headphones to mic-in and thus recorded through headphones

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I will ask her, but I don't think so.. she has recorded stuff through the mic before.. but it was usually distorted bu loud volume.. She used to use auto volume control.. mic on high sens and no attenuator..

She used the low sens, manual volume control and the attenuator at my suggestion.. but it's still no good..

I have some concerts that I want to record near the end of the month.. I have a Hi-MD My mic has it's own battery.. I tried recording in front of my hi-fi at loud volume.. with low sens, manual volume set at 20/30.. and the attenuator set at max.. with the mic battery off the volume was VERY low.. with the mic battery on.. the volume was just about high enough to be acceptable..

[greenmachine]

This maplins toy seems to lower the supplied voltage from the recorder to the microphones significantly.

[BillyBoy]

This maplins toy seems to lower the supplied voltage from the recorder to the microphones significantly.

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It would seem so...

Do you think I should dump it.. or change the settings on the MD??..

[greenmachine]

Since you have a mic with a built-in power supply, why don't you skip the attenuator and use mic-in directly for quiet to medium-loud and line-in for louder sounds?

In my experience you can't reduce distortion any further when you use a lower level setting than approximately 10/30 (mic-in / Sony recorders), for these situations plug to line-in and use anything adequate up to 30/30.

Just a suggestion, figure out what works best for you.

[BillyBoy]

Since you have a mic with a built-in power supply, why don't you skip the attenuator and use mic-in directly for quiet to medium-loud and line-in for louder sounds?

In my experience you can't reduce distortion any further when you use a lower level setting than approximately 10/30 (mic-in / Sony recorders), for these situations plug to line-in and use anything adequate up to 30/30.

Just a suggestion, figure out what works best for you.

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Thanks, I will give your ideas a few trial runs in front of my hi-fi before the concerts...

My friend with the NetMd doesn't have a battery in her mic.. she draws the power from the MD..

[greenmachine]

Two more suggestions for a better overall sound just popped into my head:

-definitely place your microphones higher than floor height, just imagine how muffled it has to sound down there...

-if you're skilled, get your microphones a proper voltage, the internal 1.5 volts battery may be sufficient for recording lectures, but not for loud music. A 9 volts block should do the job.

[A440]

I'd bet that greenmachine has found the problem: putting the mic on the floor. The sound is horrible there: muffled by the bodies of everyone in the room, bouncing around under the chairs. You wouldn't want to listen to a concert from there, and neither does your MD. Get it out in the open air.

Another question, though: what kind of mic is your friend using? If it's already a low sensitivity mic then the attenuator is probably doing more harm than good. And if it's the kind of mic that's supposed to record meetings or dictation rather than music, nothing is going to improve it.

Here in the U.S., I don't have a Maplins attenuator to experiment with, but since headphone-out jacks work in the same range internationally--possibly putting out even less power in the UK with the EU volume restrictions--I would doubt that its resistance is much greater than the Radio Shack version. But my mics are high-sensitivity, full-frequency range mics, and different mics will have different results.

[BillyBoy]

I'd bet that greenmachine has found the problem: putting the mic on the floor. The sound is horrible there: muffled by the bodies of everyone in the room, bouncing around under the chairs.  You wouldn't want to listen to a concert from there, and neither does your MD. Get it out in the open air.

Another question, though: what kind of mic is your friend using? If it's already a low sensitivity mic then the attenuator is probably doing more harm than good. And if it's the kind of mic that's supposed to record meetings or dictation rather than music, nothing is going to improve it.

Here in the U.S., I don't have a Maplins attenuator to experiment with, but since headphone-out jacks work in the same range internationally--possibly putting out even less power in the UK with the EU volume restrictions--I would doubt that its resistance is much greater than  the Radio Shack version. But my mics are high-sensitivity, full-frequency range mics, and different mics will have different results.

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Thank you for your reply..

Here are the details of my friend's mic

DAT / MiniDisc / MD Walkman / Laptop / Camcorder

(must have a Mic Input not Linein)

High Quality Ultra-Miniature Omni Directional Electret Microphone

Freq Response: 20hz - 20Khz

3.5mm Swiss Made Neutrik Gold Plated Stereo Jack Plug

24mm long Anodized Black Body

Brand New & Sealed

Very sensitive, discreet, and no wires.

Ideal for Journalists Reporters Musicians/Rappers recording meetings live music concerts etc.

MIC Spec:

Direction: Omnidirectional

Electret: Foil

Sensitivity: -41+/- 3db (RL=1.0K ohm,V=4.5 VDC) (1KHz 0db=1v/Pa)

Impedance: Max 2.2K ohms

Frequency Range: 20Hz-20KHz

S/N ratio: Min 60dB

Max sound pressure level: 115dB

Operating Voltage: 1.5V to 10V

Sensitivity reduction: less than 3dB variation from 2 to 1.5V

Current Consumption: Max 0.5ma

I also have a similar volume problem with my Hi-MD using the Maplin attenuator, my mic is .. Sony ECM-719

Thanks..

[greenmachine]

Her mic (-41dB) is about 6dB more sensitive than yours (-47dB). That means you'll propably get even quieter results with a similar setup.

[BillyBoy]

Her mic (-41dB) is about 6dB more sensitive than yours (-47dB). That means you'll propably get even quieter results with a similar setup.

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Thanks,

It would seem that the best thing for us both to try .... is to stop using the attenuator .. it does seem to drastically reduce the volue input to the MD.. I appreciate that a bit of trial-and-error is probably on the cards..

I think I will try these settings:

mic on low sens

manual volume control

20/30 for my Hi-MD ... and about 50% on my friend's NetMD

Should I use my mic with its battery turned on... or leave it off and draw the power from the MD?

Thanks

[greenmachine]

Since the mic's internal battery gives just 1.5 volts and the md preamp at least the same voltage (2.5 volts for mine), it would propably be wasted energy to use the mic's internal battery.

If you ever need to plug it directly to line-in (for very loud situations), you need to use the internal mic battery or an external power supply a.k.a 'battery box', since there is no power supply from the recorder.

[deadwing]

This maplins toy seems to lower the supplied voltage from the recorder to the microphones significantly.

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I'd interested to know what you base that conclusion on?

To be honest, I'd have said the big reason for the poor sound/low volume recording is where the taper put the unit. I've used the Maplins attenuator now on about 10 recordings, with the mics attached to lapels/jacket pockets and it works perfectly.

[greenmachine]

I'd interested to know what you base that conclusion on?

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I tried recording in front of my hi-fi at loud volume.. with low sens, manual volume set at 20/30.. and the attenuator set at max.. with the mic battery off  the volume was VERY low.. with the mic battery on.. the volume was just about high enough to be acceptable..

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[BillyBoy]

Thank you so much, you have been most helpful.. I will talk to my friend about putting the mic in a more suitable position... before her next concert ... I must say that I dont have too much faith in the attenuator.. but I will do some more experimenting at home in front of my hi-fi.. at loud volume

Thanks again..

[greenmachine]

good luck

[greenmachine]

To quote Sony (found on page 19 of the MZ-B10's instruction manual):

"When using a plug-in power-type microphone, the microphone can be operated even when its power switch is turned off since power is supplied from the recorder itself. If you are using the optional stereo microphone ECM-719, set the power switch on the microphone to OFF to allow the recorder to provide power to the microphone. It is recommended that you set the witch on the microphone to OFF during use."

This has been written for standard use (mic directly to mic-in).

By the way, what does this music/voice mode switch affect on your ecm-719?

I couldn't find an instruction manual for the mic itself.

[BillyBoy]

To quote Sony (found on page 19 of the MZ-B10's instruction manual):

This has been written for standard use (mic directly to mic-in).

By the way, what does this music/voice mode switch affect on your ecm-719?

I couldn't find an instruction manual for the mic itself.

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Thanks for this..

The mic instructions simply say to switch to voice at meetings etc. and to music for things like concerts..

. what's the point of having a battery in the mic if they suggest you don't use it..

I've done a bit more experimenting in front of my hi-fi...

1) recorded directly from mic with battery off.... result.. not bad volume

2) recorded directly from mic with battery on.... result.. same as above

3) recorded from mic with attenuator . mic battery on.... result.. 1/4 of the above volume

4) recorded from mic with attenuator mic battery off.... result.. almost zero..

the volume on the hi-fi was the same throughout... interesting ain't it?.. the attenuator really does drastically restrict the sound getting to the MD

I bought 3 of these attenuatots.. and thge result is the same on all of them...

[greenmachine]

The mic instructions simply say to switch to voice at meetings etc. and to music for things like concerts...

But what does it do?

what's the point of having a battery in the mic if they suggest you don't use it..

There are recorders / mic preamplifiers without 'plug in power', where you have to use the mic's battery.

the attenuator really does drastically restrict the sound getting to the MD

Even worse: it seems to drastically restrict the 'plug in power' voltage getting to the mics. Looks like it's only usable if the mics are powered separately.

What do you consider to be 1/4 the volume? Can you express it in dB?

Will you test mics (battery on) to line-in too?

[BillyBoy]

But what does it do?There are recorders / mic preamplifiers without 'plug in power', where you have to use the mic's battery.Even worse: it seems to drastically restrict the 'plug in power' voltage getting to the mics. Looks like it's only usable if the mics are powered separately.

What do you consider to be 1/4 the volume? Can you express it in dB?

Will you test mics (battery on) to line-in too?

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The voice/music switch on the mic.. Voice = is for picking up voice in meetings or lectures the setting is directional for focusing on a single sound source

music = picks up broader sound such as sound in concerts, a wide range of sound is picked up..

1/4 of the volume I got when recording directly with the mic... I don't know how to measure it in dB.. but when I imported the 2 files into Audition.. the one recorded with the mic only.. was about 1 inch wide.. and the one recorded with the attenuator with the mic battery on.. was about 1/4 inch wide.. that's about the best I can do to explain it..

I will test it with line in tomorrow if you think it's worth it ... should I use the attenuator with this?..

[greenmachine]

The voice/music switch on the mic.. Voice = is for picking up voice in meetings or lectures the setting is directional for focusing on a single sound source

music = picks up broader sound such as sound in concerts, a wide range of sound is picked up..

I see, sounds like only one of both mics will be used for directional voice recording.

1/4 of the volume I got when recording directly with the mic... I don't know how to measure it in dB.. but when I imported the 2 files into Audition.. the one recorded with the mic only.. was about 1 inch wide.. and the one recorded with the attenuator with the mic battery on.. was about 1/4 inch wide.. that's about the best I can do to explain it..

You can read the peak amplitude from the waveform statistics in Audition. Select 'Statistics...' from the 'Analyze' menu - there you can read the 'Peak Amplitude' for each channel separately.

I will test it with line in tomorrow ... should I use the attenuator with this?..

Definitely not, using line-in alone gives about 20 dB attenuation compared to mic-in low-sensitivity at the same level setting, which is a lot. You may want to begin with full level (30/30) if the source is not deafening loud. Edited May 24, 2005 by greenmachine

[deadwing]

But what does it do?There are recorders / mic preamplifiers without 'plug in power', where you have to use the mic's battery.Even worse: it seems to drastically restrict the 'plug in power' voltage getting to the mics. Looks like it's only usable if the mics are powered separately.

What do you consider to be 1/4 the volume? Can you express it in dB?

Will you test mics (battery on) to line-in too?

←

Again, what are you basing this assertation on regarding the attenuator?

I know you gave a 'clever' answer further up the thread, but you missed out the really important part from the reply you quoted-the lack of volume is surely down to the placing of the unit and mics on the floor, in who knows what (under a coat? a bag? )- so it's a huge jump to say 'It's the Attenuator'.

I'm using the attenuator just fine, and so are a few others who've posted onto various threads

[A440]

Yes, the attenuator is lowering the voltage from MD to mic. That's how it lowers the volume on the headphones it's supposed to be used with.

Your friend's mics sound very music-friendly--or is it a mono mic??? But it is sensitive. If she is recording music with any significant bass, then her mic preamp will overload without something to limit the incoming signal. I used Low Sens and Manual Volume of 10/30 with no attenuator at a Norah Jones concert--not exactly headbanging stuff--and the bass drum still overloaded the preamp every time it was ever so gently thumped. So her choices are the attenuator through Mic-In (small, imperfect, works for me) or a battery box through Line-In (bigger, better, but recordings will still be pretty quiet).

If she goes directly into mic-in at a standard rock concert I can promise that she'll regret it. I still think her problem was having the mic on the floor.

Your ECM-719, on the other hand, has a frequency response of 100-15,000 Hz. That means it's not getting the bottom two octaves of bass, which is how Sony gets around its preamp problems. You could try recording without an attenuator and see if you overload. Cranking up the bass on your stereo should tell you.

[greenmachine]

Again, what are you basing this assertation on regarding the attenuator?

I know you gave a 'clever' answer further up the thread, but you missed out the really important part from the reply you quoted-the lack of volume is surely down to the placing of the unit and mics on the floor, in who knows what (under a coat? a bag? )- so it's a huge jump to say 'It's the Attenuator'.

I'm using the attenuator just fine, and so are a few others who've posted onto various threads

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Haha, you almost sound like you were selling it. Do you?

What you are missing is that he did another comparison in front of his loudspeakers today, see post #21. If you look closely, you'll see the problem.

Edited May 25, 2005 by greenmachine

[BillyBoy]

What you are missing is that he did another comparison in front of his loudspeakers today, see post #21. If you look closely, you'll see the problem.

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I took a dB reading in Audition as you suggested..

Directly from the mic set at 20/30 the peak amplitude was -7.04dB

With the attenuator and the mic battery ON.. it was -19.02

[BillyBoy]

I took a dB reading in Audition as you suggested..

Directly from the mic set at 20/30 the peak amplitude was -7.04dB

With the attenuator and the mic battery ON.. it was -19.02

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My friend tells me that she recorded the concert with the mic on top of her bag.. which was ond the floor in front of her.. there was nothing covering the mic... Not the best position.. I know.. but she is very nervous about getting caught.. and being thrown out on her arse..

[A440]

Her mic is "ultra-miniature" and she shouldn't be so paranoid. I've had aisle seats at arena concerts with microphones clipped to my collar, pulling out the MD between songs to make track marks, and ushers don't notice or don't care.

Seriously, have her wear something that will camouflage the mic and clip it to a collar, or clip it to a handbag strap. She'll never get a good recording from floor level. If she got it in the door, then she has little to worry about.

[deadwing]

Haha, you almost sound like you were selling it. Do you?

What you are missing is that he did another comparison in front of his loudspeakers today, see post #21. If you look closely, you'll see the problem.

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well, my name is Mr A.Tenuator :-)

I did see that, and of course the attenuator lowers the volume reaching the MD-that is what it is supposed to do-there would be no point having it if it didn't, but you will never recreate the same scenario you are going to get at a concert though your Hi Fi. I can turn my Hi Fi to 11 (It's a heavy metal music system, so it goes one higher!!!) and record onto my MD in pretty good quality from the mics, but use those same peramaters at a concert, and I'll be lost in a sea of distortion.

On the 'staying stealthy' -with so many people checking their mobile phones during gigs these days, you really have to make it obvious what you are doing to get caught during a recording.

[greenmachine]

I did see that, and of course the attenuator lowers the volume reaching the MD-that is what it is supposed to do-there would be no point having it if it didn't, but you will never recreate the same scenario you are going to get at a concert though your Hi Fi. I can turn my Hi Fi to 11 (It's a heavy metal music system, so it goes one higher!!!) and record onto my MD in pretty good quality from the mics, but use those same peramaters at a concert, and I'll be lost in a sea of distortion.

But the point is that it only works as it is supposed to (about 12 dB attenuation) if the mic is powered separately. Otherwise the levels were significantly too low ('almost zero'), thus the mic doesn't get enough voltage to work properly and may even distort before the preamp does. If you need to power your mic separately anyway, it makes no sense to use an attenuator, you can go directly to line-in with potentially better results.

[A440]

There are so many apples-and-oranges comparisons going on here that even I'm starting to get confused.

If you have a powered mic, skip the attenuator and go through Line-In. No attenuator ever needed for line-in because there's no preamp to overload.

If you have a mic that doesn't pick up a lot of bass (low end of frequency response 100 hz) then try going directly into mic-in. Maybe the preamp won't get enough bass to overload. Ditto if you have a low-sensitivity mic. You'll just have to try and see.

If you have a sensitive mic that draws plug-in power AND has bass response (low end is 20 hz) either use an attenuator into mic-in or use a battery box into line-in. Attenuator method will give a louder recording but is theoretically noisier and may overload the mic itself if you're recording something ear-damagingly loud. It works fine for me at 95 percent of loud rock concerts--listen to my Gallery recordings. Battery box will be cleaner and have more dynamic range but will be considerably quieter. Look around the Gallery for battery-box recordings.

Experiment. See what works. One size does not fit all.

[BillyBoy]

There are so many apples-and-oranges comparisons going on here that even I'm starting to get confused.

If you have a powered mic, skip the attenuator and go through Line-In. No attenuator ever needed for line-in because there's no preamp to overload.

If you have a mic that doesn't pick up a lot of bass (low end of frequency response 100 hz) then try going directly into mic-in. Maybe the preamp won't get enough bass to overload. Ditto if you have a low-sensitivity mic. You'll just have to try and see.

If you have a sensitive mic that draws plug-in power AND has bass response (low end is 20 hz) either use an attenuator into mic-in or use a battery box into line-in. Attenuator method will give a louder recording  but is theoretically noisier and may overload the mic itself  if you're recording something ear-damagingly  loud. It works fine for me at 95 percent of loud rock concerts--listen to my Gallery recordings.  Battery box will be cleaner and have more dynamic range but will be considerably quieter. Look around the Gallery for battery-box recordings.

Experiment. See what works. One size does not fit all.

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Thanks everybody.. You have given me a lot of food for thought..

My friend has 2 concerts coming up this Sat - Sun in Birmingham.. I have suggested that for the first night she uses the attenuator and sets the volume to maximum.. (last time she set it to 50% and got very little sound)

I have 2 concerts coming up next Tue - Wed in London.. I am not going to use the attenuator for the first one I will set my volume at 20/30 and see what happens.. a case uf suck-it-and-see I guess..

Thanks for all the advice..

[greenmachine]

I will set my volume at 20/30 and see what happens

Why don't you just set the levels depending on the situation? The level meter may not be the fastest, most accurate and detailed, but is still usable to some extent. There's always a possibility to take a look, even if you're aiming for extreme stealth. 20/30 might be too loud for amplified music.

[A440]

Well, that solves the mystery.

She set the volume of the attenuator at 50 percent? No wonder it was so quiet, she had it virtually silenced!!!!!! It attenuates all that you need at 100 percent. Then set Manual Volume at 20/30.

For your ECM 719, please report back on how it does without attenuation. And greenmachine is absolutely right, take a look at the levels duing the show. Here's hoping it's ideal.

[BillyBoy]

Well, that solves the mystery.

She set the volume of the attenuator at 50 percent? No wonder it was so quiet, she had it virtually silenced!!!!!! 

Nooooo... she set the volume control on her NetMd to 50% .. the attenuator was set to 100%  (Maximum)  she also stuck some tape over the wheel on the attenuator to prevent it being altered accidentally...

It attenuates all that you need at 100 percent. Then set Manual Volume at 20/30.

For your ECM 719, please report back on how it does  ..

I will do that after next Tue/Wed... thanks..

without attenuation. And  greenmachine is absolutely right, take a look at the levels duing the show. Here's hoping it's ideal.

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[greenmachine]

ignore this post

Edited May 27, 2005 by greenmachine

[BillyBoy]

Well, that solves the mystery.

She set the volume of the attenuator at 50 percent? No wonder it was so quiet, she had it virtually silenced!!!!!!   It attenuates all that you need at 100 percent. Then set Manual Volume at 20/30.

For your ECM 719, please report back on how it does  without attenuation. And  greenmachine is absolutely right, take a look at the levels duing the show. Here's hoping it's ideal.

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Nooooo... Greenmachine is correct... she set the volume control on her NetMd to 50% .. the attenuator was set to 100% (Maximum) she also stuck some tape over the wheel on the attenuator to prevent it being altered accidentally...

I will report back on the ECM 719 without the attenuator after next Tue/Wed..

I will try to get a look at the level meter during the concert if poss... and if I can see it in the dark.. but I've got to start somewhere.. so I'm gonna go with 20/30 to begin with..

Edited May 27, 2005 by BillyBoy

[deadwing]

Nooooo... Greenmachine is correct... she set the volume control on her NetMd to 50% .. the attenuator was set to 100%  (Maximum)  she also stuck some tape over the wheel on the attenuator to prevent it being altered accidentally...

I will report back on the ECM 719 without the attenuator after next Tue/Wed..

I will try to get a look at the level meter during the concert if poss... and if I can see it in the dark.. but I've got to start somewhere.. so I'm gonna go with 20/30 to begin with..

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Is there going to be a support act? Ideal for getting a basic level. I was at a very loud gig last night and didn't need to be quite as 'stealthy' as normal as I got myself into a little alcove so I got to position the mics easily and was able to keep an eye on the levels. My mics are non powered so I have to use the mic input and had to record at 16/30 with the attenuator at 100%. Glad I did because the sound cranked up considerably during the show, but the levels never got close to max-ing out.