Connecting a Bose L1 Compact

PraiseTheLord · Post by **PraiseTheLord** » Sun Jul 19, 2015 6:54 pm

I recently purchased a Bose L1 Compact, and have been trying different ways to connect it to my Pa900.

The default seems to be an unbalanced TS Mono cable, and I must say it sounds wonderful, and has added a lot to the sound, especially when I perform in longer room.

However, I've seen other guys connecting using two cables from the left and right outputs and then combining them using some kind of adapter. I have successfully used an adapter of 2 female ts to one male ts which I then plug into the Bose. This also sounds wonderful, but I'm not sure it's actually better.

Others talk about connecting into the RCA connections or the 1/8 inch stereo connection in the Bose. But I can't get this to work. I get a bad hum connecting this way.

How do you connect?

Nemik · Post by **Nemik** » Sun Jul 19, 2015 7:21 pm

The hum is coming from cheap unbalanced cable, at least most the times.
If you have RCA input, use it, buy good balanced cable 1/4 to RCA.
If you got switch, put in position Line (not guitar 1/4")
I learn on my own, don't be cheap on cables, is a lot different in quality using good cables.
Try to stay away from any kind adapters.!
For this type connection I'm using Live Wire 1/4" - RCA Dual Patch Cable
http://www.musiciansfriend.com/accessor ... atch-cable

--..Your cable is your sound. Superior wiring allows your signal to be quiet, eliminating frustrating hums, buzzing, and crackles.

PraiseTheLord · Post by **PraiseTheLord** » Sun Jul 19, 2015 7:39 pm

Hi Nemik

I tried an adapter on the regular cables, and both these cables, which seem to be similar spec and quality to the one you posted:

http://smile.amazon.com/gp/product/B004 ... ge_o01_s00

and

http://www.sweetwater.com/store/detail/DKQR10

I had the hum in every case. Both keyboard and Bose plugged into same power strip. No other equipment plugged in.

Thoraldus · Post by **Thoraldus** » Sun Jul 19, 2015 7:55 pm

Perhaps a DI Direct Box would be the ticket?

PraiseTheLord · Post by **PraiseTheLord** » Sun Jul 19, 2015 8:37 pm

Is that how you connect yours, Rick?

Thoraldus · Post by **Thoraldus** » Sun Jul 19, 2015 8:38 pm

PraiseTheLord wrote:Is that how you connect yours, Rick?

Yes.

PraiseTheLord · Post by **PraiseTheLord** » Sun Jul 19, 2015 8:39 pm

How do you get from the DI Box to the Bose?

Thoraldus · Post by **Thoraldus** » Sun Jul 19, 2015 8:41 pm

PraiseTheLord wrote:How do you get from the DI Box to the Bose?

Balanced XLR to TRS cables.

Here's the DI

PraiseTheLord · Post by **PraiseTheLord** » Sun Jul 19, 2015 8:53 pm

Just one, into the Line Input?

Thoraldus · Post by **Thoraldus** » Sun Jul 19, 2015 8:54 pm

PraiseTheLord wrote:Just one, into the Line Input?

Yes, if you have just one L1 --- two for stereo system.

PraiseTheLord · Post by **PraiseTheLord** » Sun Jul 19, 2015 9:38 pm

OK, so this non-engineer wants to know why is that better than just connecting the unbalanced cable in on its own or combining via an adapter?

Thoraldus · Post by **Thoraldus** » Sun Jul 19, 2015 11:20 pm

PraiseTheLord wrote:OK, so this non-engineer wants to know why is that better than just connecting the unbalanced cable in on its own or combining via an adapter?

Balanced audio connections use a number of techniques to significantly reduce noise.

A typical balanced cable contains two identical wires, which are twisted together and then wrapped with a third conductor (foil or braid) that acts as a shield. The two wires form a circuit carrying the audio signal; one wire is in phase with respect to the source signal, the other wire is reversed in polarity. The in-phase wire is called non-inverting, positive or "hot" while the out-of-phase wire is called inverting, phase-inverted, anti-phase, negative or "cold". The hot and cold connections are often shown as In+ and In− ("in plus" and "in minus") on circuit diagrams.

The term "balanced" comes from the method of connecting each wire to identical impedances at source and load. This means that much of the electromagnetic interference will induce an equal noise voltage in each wire. Since the amplifier at the far end measures the difference in voltage between the two signal lines, noise that is identical on both wires is rejected. The noise received in the second, inverted line is applied against the first, upright signal, and cancels it out when the two signals are subtracted.

This differential signal recombination can be implemented with a differential amplifier. A balun may also be used instead of an active differential amplifier device.

The wires are also twisted together, to reduce interference from electromagnetic induction. A twisted pair makes the loop area between the conductors as small as possible, and ensures that a magnetic field that passes equally through adjacent loops will induce equal levels of noise on both lines, which is canceled out by the differential amplifier. If the noise source is extremely close to the cable, then it is possible it will be induced on one of the lines more than the other, and it won't be canceled as well, but canceling will still occur to the extent of the amount of noise that is equal on both lines.

The separate shield of a balanced audio connection also yields a noise rejection advantage over an unbalanced two-conductor arrangement (such as used in typical home stereos) where the shield must also act as the signal return wire. Any noise currents induced into a balanced audio shield will not therefore be directly modulated onto the signal, whereas in a two-conductor system they will be. This also prevents ground loop problems, by separating the shield/chassis from signal ground.

PraiseTheLord · Post by **PraiseTheLord** » Mon Jul 20, 2015 2:10 am

That'll teach me to ask

Seriously, thanks.

Anyone else use a Compact connected to their Pa900?

Thoraldus · Post by **Thoraldus** » Mon Jul 20, 2015 2:15 am

PraiseTheLord wrote:That'll teach me to ask

Seriously, thanks.

Anyone else use a Compact connected to their Pa900?

I did leave out all the math and formulas.

PraiseTheLord · Post by **PraiseTheLord** » Mon Jul 20, 2015 2:21 am

Phew, you're a good man, Rick.