Dear fellow audiophiles,

I'm looking for the opposite of a 10db pad for my unidirectional ECM-66B
lavalier mike. Its output turns out to be quite a bit lower than is ideal
for the Edirol R-1 recorder's mic input, averaging about 10db lower than is
ideal for good SN/R, even with the R-1's input volume set to maximum!

Don't know whether such an animal exists, but I figured this would be a
good place to ask. If a really tiny very portable 10db gain doohinky thingy
doesn't even exist, I'd be open to other suggested solutions. Thanks much.

Cheers,

Charles

Charles H. Riggs, III wrote:
Dear fellow audiophiles,

I'm looking for the opposite of a 10db pad for my unidirectional ECM-66B
lavalier mike. Its output turns out to be quite a bit lower than is ideal
for the Edirol R-1 recorder's mic input, averaging about 10db lower than is
ideal for good SN/R, even with the R-1's input volume set to maximum!

Don't know whether such an animal exists, but I figured this would be a
good place to ask. If a really tiny very portable 10db gain doohinky thingy
doesn't even exist, I'd be open to other suggested solutions. Thanks much.

Cheers,

Charles


One possibility perhaps you want to check out is the Boostaroo headphone
amp:

http://www.radioshack.com/product.as...t%5Fid=33-1109

Since it is designed for headphone output amplification, it may not have
a low enough noise floor for your application, and the gain may not be
high enough. But it does run on AA batteries and is fairly compact. The
Boostaroo site says that you can parallel outputs to get more gain, but
I am not sure how that works driving high impedances. Radio Shack has a
liberal return policy, so there is no risk in trying it out.

It has 1/8" ins and outs, so you may need some adaptors/cables which RS
carries. If you do try it, I would like to know how it turns out.

"Charles H. Riggs, III" wrote in message
...
Dear fellow audiophiles,

I'm looking for the opposite of a 10db pad for my unidirectional
ECM-66B
lavalier mike. Its output turns out to be quite a bit lower than is ideal
for the Edirol R-1 recorder's mic input, averaging about 10db lower than
is
ideal for good SN/R, even with the R-1's input volume set to maximum!

Don't know whether such an animal exists, but I figured this would be
a
good place to ask. If a really tiny very portable 10db gain doohinky
thingy
doesn't even exist, I'd be open to other suggested solutions. Thanks
much.


To the best of my knowledge, it doesn't exist. My guess is you will have to
buy a small mic preamp box with substantial gain, and then run it into your
Edirol as a line input. These boxes almost always come in stereo pairs
these days, but a few are made for single mic/voice/instrument running into
computer line ins. Usually today the box can feed either a firewire or usb
signal into a computer in digital form, but most also include analog
outputs. There are a lot of them out there, with prices ranging from $200
up to $1200. You can also get strictly analog mic preamps in numbers
ranging 2-8 in rack mounts, at a cost of about $400 up to as much as $4000.
These preamps vary greatly in sonics and build quality, and you need to take
your Eiderol and audition before you consider buying. You'll find them at
pro sound shops as well as online. You can get a feel for what's available
online at the websites for B&H (www.bhphotovideo.com) .

Hope this helps and good luck.

Harry

"Chung" wrote in message
...
One possibility perhaps you want to check out is the Boostaroo headphone
amp:

http://www.radioshack.com/product.as...t%5Fid=33-1109
Since it is designed for headphone output amplification, it may not have
a low enough noise floor for your application, and the gain may not be
high enough. But it does run on AA batteries and is fairly compact. The
Boostaroo site says that you can parallel outputs to get more gain, but
I am not sure how that works driving high impedances. Radio Shack has a
liberal return policy, so there is no risk in trying it out.

Sounds fascinating, I just called my local Radio Shack and they DO have it
in stock, and I'm on my way to buy it. Crossing my fingers. If this works
you will be rewarded forever in that great sound room in the sky!

Cheers,

Charles

"Chung" wrote in message
...
One possibility perhaps you want to check out is the Boostaroo headphone
amp:

http://www.radioshack.com/product.as...t%5Fid=33-1109
Since it is designed for headphone output amplification, it may not have
a low enough noise floor for your application, and the gain may not be
high enough. But it does run on AA batteries and is fairly compact. The
Boostaroo site says that you can parallel outputs to get more gain, but
I am not sure how that works driving high impedances. Radio Shack has a
liberal return policy, so there is no risk in trying it out.

"Charles H. Riggs, III" wrote in message news:...
Sounds fascinating, I just called my local Radio Shack and they DO have it
in stock, and I'm on my way to buy it. Crossing my fingers. If this
works
you will be rewarded forever in that great sound room in the sky!

Well, you're not quite there yet, but the idea worked almost exactly as
advertised. Yes, all the levels and impedance and all of that good stuff
worked fine going into the Mic input. Yes, this configuration won me a VERY
substantial amount of gain, and it certainly cured the problem of audio
files with the highest peaks at -20!

However, I'm afraid you were also right in the sense that the headphone
booster added some noise of its own.

So now the big $60000 question: Did the noise level improvement resulting
from the higher gain more than compensate for the added noise level from the
headphone boost?

Tomorrow, when I won't be running the risk of getting kicked out of my
apartment for playing loud music too late, I will make a snippet of a
recording from the same live opera CD I have in my collection (Fleming's
Armida) doing it both ways, without the headphone boost and then with. I'll
post the resultant audio file for anyone interested in offering an opinion
as to which is better. This should be interesting!

Cheers,

Charles

Charles H. Riggs, III wrote:
Dear fellow audiophiles,

I'm looking for the opposite of a 10db pad for my unidirectional
ECM-66B
lavalier mike. Its output turns out to be quite a bit lower than is
ideal
for the Edirol R-1 recorder's mic input, averaging about 10db lower than
is
ideal for good SN/R, even with the R-1's input volume set to maximum!

Don't know whether such an animal exists, but I figured this would be
a
good place to ask. If a really tiny very portable 10db gain doohinky
thingy
doesn't even exist, I'd be open to other suggested solutions. Thanks
much.

I have a suspicion that there's something wrong with either the mike or the
Edirol. The output rating for that mike is substantial. Your problem
should be excess output--not insufficient. Either that, or you're way too
far from the source. Are you recording bird calls?

You might try a few experiments. Turn the mike off and see what kind of
noise you get from your recorder. IOW, try to find out if the problem is in
the recorder itself.

Norm

Charles H. Riggs, III wrote:
"Chung" wrote in message
...
One possibility perhaps you want to check out is the Boostaroo headphone
amp:

http://www.radioshack.com/product.as...t%5Fid=33-1109
Since it is designed for headphone output amplification, it may not have
a low enough noise floor for your application, and the gain may not be
high enough. But it does run on AA batteries and is fairly compact. The
Boostaroo site says that you can parallel outputs to get more gain, but
I am not sure how that works driving high impedances. Radio Shack has a
liberal return policy, so there is no risk in trying it out.

"Charles H. Riggs, III" wrote in message news:...
Sounds fascinating, I just called my local Radio Shack and they DO have it
in stock, and I'm on my way to buy it. Crossing my fingers. If this
works
you will be rewarded forever in that great sound room in the sky!

Well, you're not quite there yet, but the idea worked almost exactly as
advertised. Yes, all the levels and impedance and all of that good stuff
worked fine going into the Mic input. Yes, this configuration won me a VERY
substantial amount of gain, and it certainly cured the problem of audio
files with the highest peaks at -20!

However, I'm afraid you were also right in the sense that the headphone
booster added some noise of its own.

So now the big $60000 question: Did the noise level improvement resulting
from the higher gain more than compensate for the added noise level from the
headphone boost?

Tomorrow, when I won't be running the risk of getting kicked out of my
apartment for playing loud music too late, I will make a snippet of a
recording from the same live opera CD I have in my collection (Fleming's
Armida) doing it both ways, without the headphone boost and then with. I'll
post the resultant audio file for anyone interested in offering an opinion
as to which is better. This should be interesting!

Cheers,

Charles

The added noise comes from the booster amp. The headphone power amps
used inside are some Philips IC's that are not designed to be good in
noise performance. If you are a DIY'er, you can replace those IC's with
low-noise op amps and get a significantly better noise floor. You need
to be able to cut and jump traces, and solder wires.

I think I saw the schematic of the boosteroo (that's what its other name
is) somewhere online, but I can't find it now. If I can look at the
schematic and the spec sheet of the Philips part, I can tell you what
noise degradations you would suffer, based on the output level of the
microphone.

The overall signal-to-noise may be a little better than before, I don't
know. On the one hand, you are driving your mic input with a stronger
signal, therefore you suppress the noise of that stage and you have more
effective bits to work with (assuming that the mic input goes into an
A-to-D converter). On the other hand, the signal that goes into the mic
input now has significant amount of noise added.

Well, if that does not work out, you still have a nice headphone booster
that works very well with notebook PC's. Or just get a refund.

Charles H. Riggs, III wrote:
"Chung" wrote in message
...
One possibility perhaps you want to check out is the Boostaroo headphone
amp:

http://www.radioshack.com/product.as...t%5Fid=33-1109
Since it is designed for headphone output amplification, it may not have
a low enough noise floor for your application, and the gain may not be
high enough. But it does run on AA batteries and is fairly compact. The
Boostaroo site says that you can parallel outputs to get more gain, but
I am not sure how that works driving high impedances. Radio Shack has a
liberal return policy, so there is no risk in trying it out.

"Charles H. Riggs, III" wrote in message news:...
Sounds fascinating, I just called my local Radio Shack and they DO have it
in stock, and I'm on my way to buy it. Crossing my fingers. If this
works
you will be rewarded forever in that great sound room in the sky!

Well, you're not quite there yet, but the idea worked almost exactly as
advertised. Yes, all the levels and impedance and all of that good stuff
worked fine going into the Mic input. Yes, this configuration won me a VERY
substantial amount of gain, and it certainly cured the problem of audio
files with the highest peaks at -20!

However, I'm afraid you were also right in the sense that the headphone
booster added some noise of its own.

So now the big $60000 question: Did the noise level improvement resulting
from the higher gain more than compensate for the added noise level from the
headphone boost?

Tomorrow, when I won't be running the risk of getting kicked out of my
apartment for playing loud music too late, I will make a snippet of a
recording from the same live opera CD I have in my collection (Fleming's
Armida) doing it both ways, without the headphone boost and then with. I'll
post the resultant audio file for anyone interested in offering an opinion
as to which is better. This should be interesting!

Cheers,

Charles

I found this:

http://www.pcavtech.com/pwramp/boostaroo/

The output S/N is -94 dB relative to a .775V output. That puts the
output noise at 15 uV rms, A weighted. So, for the boostaroo to not
contribute significant noise, the signal from the microphone, measured
at the output of the boostaroo, shouldprobably be 60 dB or more above
that. That's around 15 mV rms. The boostaroo has a spec'd gain of 12 dB,
or 4X. You should now have all the data to determine if the boostaroo is
too noisy for your application, or if the noise floor of the recorder is
too high.