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Colin Henein
Guest
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 Posted:
Thu Nov 03, 2005 5:42 am Post subject:
Audio interfaces with robust preamps |
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Simple Question:
What reasonably priced audio interfaces (usb, usb2, or firewire) have
the most gain-boosting mic preamps?
Back Story:
I have just bought a Studio Projects LSD2 microphone. (It's a stereo
microphone with adjustable angle between 2 vertically coincident
condenser elements.) My plan is to use it to record live concerts using
mid-side or blumlein techniques. I had planned to get a firewire or USB
audio interface with microphone preamps and go mobile with my iBook for
recording.
The problem I have run into is that the audio interfaces I've tried
can't give me enough gain to get anything out of this microphone for
room recording. In order to get half-decent levels I have to crank the
gain up to at least 90%. Somewhere around 85% gain the interfaces I've
tried produce a lot of noise, and some high-pitched hum as well.
I've tested the mic on an old and bulky analog Yamaha mixing board that
does phantom power. It works fine, and the board's gain knob only needs
to be turned to about 50% to get great whole-room levels. No noise. No
hum. So it doesn't seem to be the microphone. It seems to be the
interface. I don't want to carry the bulky board to concerts though.
The two interfaces I've tried are the M-Audio Firewire 410 and the
PreSonus FireBox. The 410 was a poorly designed piece of crap with bad
software. The PreSonus was ok. Neither could boost the volume of the
microphone without maxing out their respective pre-amps and introducing
unacceptable amounts of noise.
Is there an interface out there that has onboard preamps with the power
to boost the LSD2 to the point that I can reliably use this as a room
mic? I really hadn't budgeted for a separate mic pre at this point.
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Kurt Albershardt
Guest
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| Posted:
Fri Nov 04, 2005 4:25 am Post subject:
Re: Audio interfaces with robust preamps |
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hank alrich wrote:
| Quote: | Colin Henein <googlegroups@juicer.orange-carb.org> wrote:
Is there an interface out there that has onboard preamps with the power
to boost the LSD2 to the point that I can reliably use this as a room
mic? I really hadn't budgeted for a separate mic pre at this point.
Metric Halo Mobile IO ULN-2
http://www.mhlabs.com/metric_halo/products
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Definitely - but may not fit his definition of 'reasonable.'
See if you (Colin) can arrange to audition a Sound Devices USBpre
<http://www.sounddevices.com/products/usbpremaster.htm>
Street price is around $550 (or was when I last looked) but they do show
up used here and on eBay from time to time. Preamps are not as good as
those in the SD mixers or recorders but far better than those in most
other laptop interfaces.
You might also ask in the Oade forum - Doug and several of the regulars
there have LSD2's and ought to be able to give you more ideas.
<http://www.oade.com/Tapers_Section/Forum/dcboard.php?az=show_topics&forum=100> |
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Jona Vark
Guest
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| Posted:
Fri Nov 04, 2005 5:27 am Post subject:
Re: Audio interfaces with robust preamps |
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"hank alrich" <walkinay@thegrid.net> wrote in message
news:1h5g50x.5fbtcy1b43sbmN%walkinay@thegrid.net...
| Quote: | Colin Henein <googlegroups@juicer.orange-carb.org> wrote:
The RNP has 66 dB of gain boost, and the review I read said it was
noisy after 60. That seems to be about the same as the FireWire 410. I
need to do better than that.
There is no comparison between the quality of sound from the RNP and
that from the 410. The 410's spec sheet came froma marketing department
and the RNP's came from a bench test.
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no bias from on' Hank there..
Of course M-Audio lets its marketing department generate their specs.
Everyone knows that. |
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Chevdo
Guest
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| Posted:
Fri Nov 04, 2005 5:43 am Post subject:
Re: Audio interfaces with robust preamps |
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In article <1131035070.522753.198680@g49g2000cwa.googlegroups.com>,
googlegroups@juicer.orange-carb.org says...
| Quote: |
No, it's because you're expecting too much out
of cheap consumer electronics.
Sigh. Fair enough I guess.
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I can lead a horse to water, but this is the last time I'll be mentioning this
in this thread. The pre-amps on these audio interfaces are fine if you don't
crank them up all the way. You know as well as I do that the pre-amps are
quiet for most of the gain stage, just not the very top. The gain ramps up
really steep at the end and thats why you get the noise only when its cranked
but not if its not cranked. They designed it this way on purpose just in
case people need really high gain (at the expense of introducing noise).
Manufacturers designed the pre-amps in 24bit audio interfaces this way
because they know that you don't need to record really hot levels at 24bit.
This design is the best compromise to get good recordings with cheap pre-amps.
And many of the people who have responded to you know this, too, but would
prefer to babble on about you needing to shell out more money for 'pro'
equipment because they are professional wankers! They want people to think
that you can't get a good signal out of 'cheap consumer electronics'. A mic
pre-amp that will deliver a markedly better signal than the ones in the audio
interfaces will cost at least $1000 and the difference will still be
negligable (providing you use the pre-amps in the audio interface properly as I
described). |
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Colin Henein
Guest
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| Posted:
Fri Nov 04, 2005 5:43 am Post subject:
Re: Audio interfaces with robust preamps |
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Update on this issue. I have tried it with a crummy (mono) Beringer mic
pre that someone loaned me (Tube ultragain Mic 100). It has the
advantage of a labelled VU meter. (-24,-18,-12,-6,0,+6,+12). In order
to hit 0 on that scale I need 54 dB of gain (with reasonable test
program material: loud bluegrass/dance band music at "concert levels"
to my ears, 20 feet from a reasonable stereo).
I have talked to Brent at Studio Projects about the problem. He says,
in his opinion the microphone should be "melting the soundcard" at 54
dB of gain. In other words, he is quite surprised by the low levels.
But if the mic were defective it would be surprising that both elements
would be failing in a matched set...
I have started asking on taper boards (and thanks Kurt for the
reference to Oade... I will post there) and I only have one reply so
far, but he said that he's never gone over 22 dB or so with his LSD2.
So the plot thickens.
I have asked Studio Projects if they will send me another unit to try
side-by-side. I will keep you all updated. Thanks to everyone who has
made suggestions so far. They are all appreciated. Feel free to keep
them coming if you think of something! |
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Colin Henein
Guest
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| Posted:
Fri Nov 04, 2005 5:43 am Post subject:
Re: Audio interfaces with robust preamps |
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Thanks for that comment. I understand your point that with 24 bits to
play with there is plenty of range for "digital zoom" of the audio. At
this point I want to be sure that my experience is in line with
expectations of others to make sure I don't have a defective component.
Your advice, though, is making me feel better about the possibility of
going back to the FireBox and enabling their digital 12 dB gain boost
to get around my problems. |
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Pooh Bear
Guest
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| Posted:
Fri Nov 04, 2005 5:43 am Post subject:
Re: Audio interfaces with robust preamps |
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Colin Henein wrote:
| Quote: | Simple Question:
What reasonably priced audio interfaces (usb, usb2, or firewire) have
the most gain-boosting mic preamps?
Back Story:
I have just bought a Studio Projects LSD2 microphone. (It's a stereo
microphone with adjustable angle between 2 vertically coincident
condenser elements.) My plan is to use it to record live concerts using
mid-side or blumlein techniques
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< snip >
It sounds to me like you're using the mic quite some considerable distance
form the source and maybe recording purely acoustic music.
This requires more gain than may typically be available from the majority
of mic pres on the market.
It would help if you talked about the mic gain in dB btw instead of x% of
the control rotation. There is no standard for max gain and x% of it is
simply less helpful still since the 'control law' varies from mixer to
mixer.
Few of the lower cost ( but perfectly good ) mic pres on the market have >
60dB gain and this may be too low for you. Recording an acoustic performanc
at a distance may require up to 80dB of gain on the mic. This will be
inherently noisy ( background hiss ). You may wish to reconsider your
recording method.
Graham |
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Kurt Albershardt
Guest
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| Posted:
Fri Nov 04, 2005 5:43 am Post subject:
Re: Audio interfaces with robust preamps |
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Chevdo wrote:
| Quote: |
A mic pre-amp that will deliver a markedly better signal than the
ones in the audio interfaces will cost at least $1000 and the
difference will still be negligable (providing you use the pre-amps
in the audio interface properly as I described).
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Assuming that by 'markedly better signal' you mean 'markedly better
sound' I must emphatically reply that my experience does not agree. |
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Pooh Bear
Guest
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| Posted:
Fri Nov 04, 2005 5:43 am Post subject:
Re: Audio interfaces with robust preamps |
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Mike Rivers wrote:
| Quote: | just live with the noise until
you can afford a serious preamp
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Actually, even the cheapest mic pres ( eg Behringer ) have their best noise
performance at high gain.
Indeed a Behringer mic pre will outperform a Neve mic pre of late 1980s
vintage noise wise.
A *serious* mic pre will not be likely to be any quieter. Technology has
found pretty much the noise floor for today's mic preamps regardless of cost.
There are actually very few mic pres today that are truly bad unless you go
out of your way to find one. As you noted the 'really nice mic preamp' is
actually *more* noisy than most on the market.
Graham |
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Pooh Bear
Guest
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| Posted:
Sat Nov 05, 2005 3:09 am Post subject:
Re: Audio interfaces with robust preamps |
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Mike Rivers wrote:
| Quote: | Pooh Bear wrote:
Actually, even the cheapest mic pres ( eg Behringer ) have their best noise
performance at high gain.
Indeed a Behringer mic pre will outperform a Neve mic pre of late 1980s
vintage noise wise.
A *serious* mic pre will not be likely to be any quieter. Technology has
found pretty much the noise floor for today's mic preamps regardless of cost.
So you're suggesting that it's useless to use a microphone that needs
more than about 55 dB of gain if you don't want to hear hiss?
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55dB of gain from one of my mic amps will result in a self noise from the mic amp
of around -73dBu.
Expect the same from Mackie, Behringer, Soundcraft etc etc...
A boutique mic pre might better that by say 1dB.
Graham |
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Bob Cain
Guest
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| Posted:
Sat Nov 05, 2005 4:33 am Post subject:
Re: Audio interfaces with robust preamps |
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hank alrich wrote:
| Quote: | Bob Cain wrote:
Colin Henein wrote:
Simple Question:
What reasonably priced audio interfaces (usb, usb2, or firewire) have
the most gain-boosting mic preamps?
Back Story:
I have just bought a Studio Projects LSD2 microphone.
What's its rated sensitivity? What would you estimate the SPL to be at
your recording point? I fully agree with Brent; if it's anywhere near
typical sensitivity for a condenser it should be "melting the soundcard"
at 54 dB gain.
Not when tracking a bluegrass band from 20 feet away, speaking from
experience.
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And I know you have more than enough of that to speak with authority.
Have you ever measured the SPL in such a situation?
Bob
--
"Things should be described as simply as possible, but no simpler."
A. Einstein |
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Bob Cain
Guest
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| Posted:
Sat Nov 05, 2005 4:50 am Post subject:
Re: Audio interfaces with robust preamps |
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Arny Krueger wrote:
With that, 54 dB of gain would raise 84 dB SPL to 2 Vrms. Hank, is this
about what one would expect from a bluegrass band at 20 ft.
Also, is 2 Vrms a reasonable approximation to 0 dBFS for line level
converters? That's what my Yamaha DS2416 does but I don't know how
typical it is.
Bob
--
"Things should be described as simply as possible, but no simpler."
A. Einstein |
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Chevdo
Guest
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| Posted:
Sat Nov 05, 2005 5:42 am Post subject:
Re: Audio interfaces with robust preamps |
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Wank, go have another lice bath.
In article <1h5hwhe.i3wl4mxfjsmeN%walkinay@thegrid.net>, walkinay@thegrid.net
says...
| Quote: |
Chevdo <chev@dont.com> wrote:
googlegroups@juicer.orange-carb.org says...
No, it's because you're expecting too much out
of cheap consumer electronics.
Sigh. Fair enough I guess.
I can lead a horse to water,
No, you try to lead ignorance to bullshit.
but this is the last time I'll be mentioning this
in this thread. The pre-amps on these audio interfaces are fine if you
don't
crank them up all the way.
Read what he posted. Those preamps are not "fine" in the contextual
circumstance.
You know as well as I do that the pre-amps are
quiet for most of the gain stage, just not the very top.
And since the very top is where he's needing to run his preamp in order
to get useful signal in a distant micing application, your point is
imaginary.
The gain ramps up really steep at the end and thats why you get the noise
only when its cranked but not if its not cranked. They designed it this
way on purpose just in case people need really high gain (at the expense
of introducing noise). Manufacturers designed the pre-amps in 24bit audio
interfaces this way because they know that you don't need to record really
hot levels at 24bit. This design is the best compromise to get good
recordings with cheap pre-amps. And many of the people who have responded
to you know this, too, but would prefer to babble on about you needing to
shell out more money for 'pro' equipment because they are professional
wankers! They want people to think that you can't get a good signal out
of 'cheap consumer electronics'. A mic pre-amp that will deliver a
markedly better signal than the ones in the audio interfaces will cost at
least $1000 and the difference will still be negligable (providing you use
the pre-amps in the audio interface properly as I described).
Bullshit. He has a low senstivity mic. Your soundcard doesn't have
enough gain for his mic in the usage he intends. End of your story.
The beginning of his story is that he either needs a hotter mic or a
stouter preamp to achieve his goals. If he can live with the pre he has
with the +12 setting, he's good to go. He ain't recording synths direct.
Those who do and want to tell folks about micing might be considered
wannabe wankers. A pre that delivers far better sound than the one he
has costs less than five hundred US dollars for two channels.
--
ha |
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hank alrich
Guest
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| Posted:
Sat Nov 05, 2005 5:42 am Post subject:
Re: Audio interfaces with robust preamps |
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Chevdo <chev@dont.com> wrote:
| Quote: | chev@dont.com says...
Incidentally, Wank, if your music is as aesthetically disgusting as your
appearance, that could explain why you are a lifelong failure.
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Yeah, Chevdood, that's all I hear from my fellow musos and clients, that
I am just too ugly to be around.
--
ha |
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Arny Krueger
Guest
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| Posted:
Sat Nov 05, 2005 5:42 am Post subject:
Re: Audio interfaces with robust preamps |
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"Mike Rivers" <mrivers@d-and-d.com> wrote in message
news:1131148002.598826.74410@g47g2000cwa.googlegroups.com
| Quote: | Bob Cain wrote:
With that, 54 dB of gain would raise 84 dB SPL to 2
Vrms. Hank, is this about what one would expect from a
bluegrass band at 20 ft.
Also, is 2 Vrms a reasonable approximation to 0 dBFS for
line level converters?
Not hardly. 2V RMS is about +8 dBu. Most "pro" (nominal
+4 dBu operating level) A/D converters give you
somewhere in the ballpark of -16 dBFS at nominal input
level. So an input of +8 dBu would give you about -12
dBFS, which is a perfectly reasonable eyeball average
level.
But given that this only fills up about 1/4 of the
waveform display area, one might think that there's
insufficient level. And one might be wrong unless one is
recording something with no dynamic range. Not my idea of
a pleasant bluegrass band.
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I'm thinking that this might be part of the problem - we
might have a new recordist who expects peak levels to fill
up the waveform display on his DAW. |
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