connections: laptop (or iPod) stereo mini to powered speakers

"TimR" <[email protected]> wrote in message
news:196eb9ae-6b76-4cbd-9fc3-672b6cc82072@56g2000hsm.googlegroups.com...
> I've tried searching the past couple weeks, still don't really
> understand this connection.
>
> I have decent speakers I run my keyboards to using XLR. They are ESI
> nEAR 05s, I'm happy with the sound, would like to run my laptop and my
> daughter's iPod through them occasionally (virtual organ emulation).
>
> But laptops and iPods only have 3.5mm stereo socketc. My speakers
> have XLR inputs as well as 1/4 in TRS inputs. The manual is online
> and says the 1/4 inch input will accept either balanced or unbalanced
> input.
>
> But I'm in Germany, there doesn't seem to be an equivalent of a Radio
> Shack, and though I have a little Deutsch it runs out very quickly
> trying to talk tech stuff.
>
> I can run laptop to home stereo, I have a cable that is 3.5 jack to
> two RCAs, but my stereo is not the quality of the nEARs. . I also
> have 3.5 splitter and 3.5 extension cables, but that still leaves me
> with stereo at the end when I think I want mono?????? at each speaker,
> and it leaves me 3.5 when I want 1/4.
>
> This must be a standard problem - is there a school solution? Am I
> just looking in the wrong direction?


The easiest way is to use your 3.5mm to 2 RCA's, and buy 2 RCA to mono 1/4
inch jack plug adaptors, like this.
http://www.morecomputers.com/extra.asp?pn=F8V3255AEA&referer=Froogle.

This will work just fine into the TRS inputs.



Gareth

there a school solution?  Am I
> > just looking in the wrong direction?
>
> The easiest way is to use your 3.5mm to 2 RCA's, and buy 2 RCA to mono 1/4
> inch jack plug adaptors, like this.http://www.morecomputers.com/extra.asp?pn=F8V3255AEA&referer=Froogle.
>
> This will work just fine into the TRS inputs.
>
> Gareth- Hide quoted text -
>
> - Show quoted text -

Thanks. I looked for RCA to mono 1/4 and didn't find it locally,
guess I need to be more persistent.

But, though this works fine on the home stereo, won't the phase be off
when I feed into TRS?

I took a look at the sound board for a band at a fest last night.
There was a CD walkman feeding the board. The cable went into the
headphone jack of the CD player, and terminated in two 1/4 inch
jacks. So it would appear somebody makes the cable I want, it didn't
look homemade. I know nothing about mixers, so I have no clue if
those are 1/4 inch mono jacks or TRS.

I notice you said easiest, not best. Is it preferable to use some
kind of audio interface or direct box out of a PC, as opposed to just
matching connections?

"TimR" <[email protected]> wrote in message
news:b4d8ab4c-5871-4621-8c1b-6c8507026590@2g2000hsn.googlegroups.com...
there a school solution? Am I
> > just looking in the wrong direction?
>
> The easiest way is to use your 3.5mm to 2 RCA's, and buy 2 RCA to mono 1/4
> inch jack plug adaptors, like
> this.http://www.morecomputers.com/extra.asp?pn=F8V3255AEA&referer=Froogle.
>
> This will work just fine into the TRS inputs.
>
> Gareth- Hide quoted text -
>
> - Show quoted text -

Thanks. I looked for RCA to mono 1/4 and didn't find it locally,
guess I need to be more persistent.

But, though this works fine on the home stereo, won't the phase be off
when I feed into TRS?





No. Although the TRS will have a balanced input, using a mono jack grounds
the Ring connection, the signal then is applied only to the Tip. This
automatically converts the TRS to unbalanced operation and will work fine.





I took a look at the sound board for a band at a fest last night.
There was a CD walkman feeding the board. The cable went into the
headphone jack of the CD player, and terminated in two 1/4 inch
jacks. So it would appear somebody makes the cable I want, it didn't
look homemade. I know nothing about mixers, so I have no clue if
those are 1/4 inch mono jacks or TRS.

I notice you said easiest, not best. Is it preferable to use some
kind of audio interface or direct box out of a PC, as opposed to just
matching connections?





You may well find that your laptop's power supply injects noise into your
desk - this is very common. The only way around this is to use a
transformer isolation box(es) between laptop and desk, so they are not
directly electrically connected in any way, signals or grounds.

Try it first though, you may not need one at all or find you can put up with
it. The alternative is to run the laptop on battery power instead.


A much more complicated solution would be a soundcard or other interface
with optical out, going to some kind of D/A converter (even something like a
broken DAT or CD burner that will still convert but not record). Using the
analogue outs on an interface may give you the same noise problems as a
direct connection. Try stuff, see what happens.



Gareth.

Just for future reference, there are powered monitors with Optical and SPDIF
ins.

Here's an example:

http://www.roland.com/PRODUCTS/EN/DM-20/index.html


Gareth.

TimR wrote:

> Thanks. I looked for RCA to mono 1/4 and didn't find it locally,
> guess I need to be more persistent.

I know you don't have a Radio Shack handy, but just to be sure you're
looking for the right things, at least check out the pictures:

Cable: http://www.radioshack.com/product/index.jsp?productId=2103859&cp=
Adapters: http://www.radioshack.com/product/index.jsp?productId=2062455&cp=

> But, though this works fine on the home stereo, won't the phase be off
> when I feed into TRS?

No, unless it's a non-standard TRS input. The tip of the plug (adapter)
will connect with the tip contact of the jack, and the sleeve of the
plug will connect to the ring and sleeve of the jack. Polarity will be
correct. The cable is wired so that one branch on the "split" end goes
to the tip of the 1/8" plug and the other goes to the ring, so one
branch is the left channel output, the other is the right channel output.

> I took a look at the sound board for a band at a fest last night.
> There was a CD walkman feeding the board. The cable went into the
> headphone jack of the CD player, and terminated in two 1/4 inch
> jacks. So it would appear somebody makes the cable I want,

People seem to find those. I believe Hosa has them in their catalog.

> I know nothing about mixers, so I have no clue if
> those are 1/4 inch mono jacks or TRS.

We know nothing about THAT mixer unless you tell us what it is. Mixers
have both unbalanced (TS) or balanced (TRS) input jacks, but generally
they're compatible. You're more likely to have trouble with a TRS plug
working in a TS jack than the other way around.

> I notice you said easiest, not best. Is it preferable to use some
> kind of audio interface or direct box out of a PC, as opposed to just
> matching connections?

Easiest, in this case, is as good as it gets. If you can find a cable
with 1/4" plugs on the mixer end, that's better than using adapters, but
only because it's one less connection to get flaky. But electrically,
there's really nothing better that you could do. If you had to locate
the recorder a significant distance from the mixer (like maybe on stage,
with the mixer at the back of the room) then you might consider running
a balanced cable between the recorder and mixer. A pair of direct boxes
(one for each channel) would work for this, or you could get an
electronically balanced line driver, but try the simple solution first.




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