

Ask HN: Noise from new furnace; How to effectively record? - pasbesoin

I know from reading comments that some here have more than a passing acquaintance with audio recording.  My new furnace is making noise intermittently; unfortunately for diagnosis&#x2F;service, largely in the later afternoon and night.  Next Tuesday will mark 11 weeks I&#x27;ve been living with this, including disrupted sleep and worry.<p>I&#x27;m becoming desperate to get this fixed -- effectively.  In order to demonstrate to the contractor -- and now wholesaler and manufacturer what is happening, I need to be able to present good recorded examples.  I don&#x27;t have a lot of money to keep trying different equipment; I&#x27;m hoping some advice from HN can steer me in the right direction.  What recording device and microphone might serve well, having flat response across the audible spectrum and not missing nor aggressively filtering out what it decides is undesired noise -- even and as that may be the sound I am after?
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tjr
Something like this would be a good, inexpensive option for a microphone:

[http://www.amazon.com/MXL-770-Cardioid-Condenser-
Microphone/...](http://www.amazon.com/MXL-770-Cardioid-Condenser-
Microphone/dp/B0007NQH98/)

For a recording device, most people use their computer. You'd need to add an
audio interface into which you can plug both the microphone (XLR) and the
computer (Firewire/USB, generally). Lots of options. The cheapest one would
probably be fine for this purpose. Then use, say, Audacity software on the
computer to record.

~~~
tjr
I've never used this one, but this may also be a fine option, and would
eliminate the need for a separate audio interface:

www.amazon.com/CAD-U37-Condenser-Recording-Microphone/dp/B001AIQGUO/

~~~
pasbesoin
Thank you very much for both responses. I looked at the first item and will
look at this next.

If it's not inconvenient, could you expand briefly on what kind of audio
interface you are speaking of? This is all quite new to me, and I'm as yet
unclear on what I should be looking for. (I don't know -- yet -- how such a
set up hangs together.)

Audacity I'm passingly familiar with and think I can further figure out.

P.S. I'm also looking and can probably figure out on my own. So no worries if
it's not convenient -- this already gives me a/the direction to look in.

P.P.S. Browsing Amazon now with the browser that does not have NoScript, I see
links to interface products appearing on those pages. Operating on 5 hours of
sort of sleep, here...

~~~
tjr
Sure. Something like this would probably work just fine for your needs:

[http://www.sweetwater.com/store/detail/AudioBoxUSB/](http://www.sweetwater.com/store/detail/AudioBoxUSB/)

There's all sorts of more expensive interfaces (and microphones) that you can
buy, but for what you're describing, they likely wouldn't help much. I don't
think you're needing to do professional foley recording of your furnace for a
major motion picture. :-)

So in sum, if you went the separate interface/microphone route, you'd have
something like:

\- microphone sitting on microphone stand, say, eighteen inches away from the
furnace. If you don't know exactly where the sound is coming from, set the
stand so the mic is about half-way up the height of the furnace.

\- XLR cable running from microphone to audio interface

\- audio interface connected to your computer via USB or FireWire or whatever
cable (based on your selection of interface)

\- For that particular microphone, it needs to be powered by the interface, so
press the 48v button on the interface to activate the power to the mic.

You'll need to adjust the input knobs and such on the interface ensure getting
adequate audio signal. I can't tell you exactly what to set it to without
being familiar with the particulars, but it shouldn't be hard to figure out.
(You can record digital audio at a very low level and it still turns out
usable, but if you record too high, it clips, and is pretty much ruined. So
favor too quiet rather than too loud, if you're not sure, and boost the level
in Audacity, if needed.)

~~~
pasbesoin
I ordered the USB microphone with next day shipping (a bit excessive, but that
will ensure it's here in time for our next major transition to colder
weather).

If that doesn't do well enough, I'll follow up with the microphone that
requires a separate interface. This gives me a little more time to investigate
those details and to talk myself into the $200 or so.

Thanks again, so much. I knew there must be good choices out there, but wading
in with zero knowledge felt kind of overwhelming, especially on top of the
stress of the circumstances.

Years ago, people would tell me I should do voice acting (voice-overs --
whatever the right term is). (I never really heard that, in my own voice.) Who
knows, maybe I'm inadvertently on the cusp of my new career.

------
pasbesoin
I realize this may be a bit OT for HN. My karma here's generally decent, and
on a personal level I could really use the help.

Also, this and some other experiences with noise have me thinking again about
learning to design products and services that help people document
unreasonable noise and get it addressed. Whether a malfunctioning appliance or
piece of equipment, or the neighbour kids with the booming subwoofer. Timing,
localization, and calibrated measurement of intensity.

\--

It's actually been a series of noises that have changed after each of the two
attempts at repair. I have an older analog tape cassette recorder whose built-
in microphone captured the first sound fairly well.

The built-in microphone of an old iAudio MP3 player with a record function
didn't capture that sound well, but it did capture the lower sound made after
the first repair.

Between the two devices, I assumed one would capture the "in between" sound
that followed the second repair. However, both built-in microphones seem to be
"dead" in that frequency range.

I borrowed a Sony "stick" digital voice recorder when the first repair
produced the second noise profile, but it did not seem to register this at
all. I don't have the manual for it, but I've played with / guessed at its
settings, and it is now picking up the third noise following the second repair
to some extent, but not too well. It does have a microphone in mini-jack.

P.S. While I've learned that more minor noise with this unit hints at the real
trouble to come, I'm not what is just a minor background noise. I'm speaking
of "wake you in the middle of the night", give you headaches at your home
office work desk types of noise. Unfortunately, since particularly the more
recent noises are intermittent, I can't count on them manifesting for the very
limited time a service technician may be on-site.

