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Subject: Re: microphones
From: Chris Holt (amiga2k_at_cox.net)
Date: 2003-02-16


----- Original Message -----
From: "fille" <fille_at_nibewege.org>
To: <rockbox_at_cool.haxx.se>
Sent: Sunday, February 16, 2003 10:00 AM
Subject: microphones

> Hello ,
>
> I own a Archos Jukebox recorder 20 . I noticed that , when i'm recording
> sound with the internal microphone , it also records the sound of the
> spinning disk, every now and then (but too often ;p ). I don't think
> there's anything i can do about that . So i decided to buy an external
> microphone. Now i have a few questions concerning this matter.

Yep, short of filtering it out post-recording, I don't think there is any
other way to get rid of this audible as opposed to electrical noise.

> - does the microphone need a battery , or does the archos work with those
> small microphones without a battery ? I was told it doesnt matter , but i
> want to be sure.

Batteries are included in electret condenser mics to bias the transistor in
them. Without the battery they are a stick on a wire and don't do anything
worthwhile. Whether the mic needs a battery or not is the design of the mic
and has nothing to do with the Archos.

> - I saw Archos sells pre-amped mics for around 35 euro here . Did anyone
> try it ? Or should e.g. a Sony be better ? Is a pre-amped microphone
> necessary ?

Yes, if you notice the jack is labeled "line-in" so it requires a line level
signal to be input. Preamped microphones put out a line level signal,
others do not. Someone has tried the Archos microphone and they said it was
adequate.

> - I want to record dj mixes at a local party , does the Archos deal with
> too high incoming volumes ? Does it autocompress the sound or will i get ,
> what is called in dutch : 'overstuwing' , a messy boosty sound , like when
> you shift up the volume too high but your boxes cant handle it and start
> sounding bad . If the answer is yes , how can i overcome that problem ?

You need to adjust the recording levels properly so there is no clipping
(which I believe is the word you are looking for) But... If you are
talking about using an electret (condenser) microphone, then the clipping
can take place in the microphone with this type of mic. Obviously there is
nothing the Archos can do about that. Use a dynamic (preamplified)
microphone or an electret microphone with a high bias like a 9v battery. If
you use a battery box, you can get some with bass roll-off filters that can
help to eliminate the excessive bass that these microphones sometimes
record. Battery boxes and preamps all get pretty expensive though. Best
bet is to get the DJ to allow you to plug the Archos into his rig.

> - Can a digital microphone be used with the digital in ? Or is the word
> digital misleading in this matter ?

These are VERY expensive (unless you are talking about the USB crap which
will NOT work for the Archos) and are simply conventional condenser capsule
microphones with A/D converter and preamp built into the housing. I don't
see why they wouldn't work, but you are stuck with what you buy as opposed
to buying a good condenser mic, battery box and ADC, any of which can be
upgraded at will.

> something not about mics:
> - Is it safe to use the line in directly from e.g. a television (with the
> red and white from the tv to normal jack for the line-in) , or is their a
> risk to blow up the Archos recorder?

If it's a standard line level output, no problem. Some TV sets have
variable outputs, so you may want to turn the volume down and then bring it
up till you get what you need. Even so, it's not likely that these will put
out damaging levels. If the levels aren't variable then you will get the
same thing no matter what.

> Thanx chaps ,
>
> Fille / Belgium

NP
Chris



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