Hi,

Someone suggested in another post in reference
to micing your drum kit toms and snare/hh:

"Running the 57 's out of phase (so the bass gets cancelled) with a simple phase-reversing "Y" cord (one XLRF in the "Y" has 2 and 3 reversed)"

I didn't quite get it (sorry).

1) Do I buy one these:

http://www.almeida.com/bose/Male2Female_XY.gif

2) And then rewire one of them? How exactly?

3) Why is running out of phase an advantage?

Thanks!
Carlos Almeida
Drummer/Leader http://www.siliconvibe.com
Original Post
Carlos,

Hi!

Running two inputs 180° out-of-phase puts the peaks and valleys of the sine wave so that they null each other out when summed (see the middle picture below). This has a tendency to cancel out both inputs, and is quite pronounced in the "far" field, but negligible in the "near" field. Normally phase cancellation is undesirable, but when you know what you want (and in this case, what you don't want) then you do it deliberately.

I found an illustrated example here

- click to see the full animation and explanation.

Wiring:
Yes, you can start with an adapter like the one in the picture


Open one of the female connectors, unsolder, reverse and resolder the wires running to pins 2 and 3.

It looks like you might want an adapter with longer cables. Those look very short.

Pete (user Drumr) wrote to me a couple of weeks ago, about how he made the cable.

" Okay...I made the cable tonight. Pretty simple;
Cut the male ends off the two "to mic" cables,
and the female end off the "to mixer" cable.

Took the exposed wires on the "mic" cables and soldered the ground to ground and swapped the black & white (pin 2&3) wires and soldered.

Then took mixer end cable and soldered ground to ground and the two other leads to the other two...no way to screw it up. Heat shrink tubed the whole works...very nice looking job.

Tested it with a couple mics and they both work.
No way to test the phase really, but they both sounded fine to me.
"

edit - correction about low frequencies and added clarification about near and far fields...
Hi,

Excellent Acoustical Explanation - Thanks!
I think I can build one now.

However Musically Speaking - Could you please
bottom line it for me.
What will I hear differently out of the
Bose via micing the drums this way instead
of just using a Y chord that is in phase.
Why are drummers going through the trouble?

Thanks!
Carlos
Hi Carlos,

I (think I) understand the physics, but for musical question I should let Cliff-at-Bose or Pete (Drumr) answer.

Cliff-at-Bose said
"Snare gets into everything. You just can't stop a good snare. So, the out-of-phase cancels the far field but each separate mic picks up local bass, like from toms. Just moving the mic is such a more organic way to tune the kit, rather than lots of mics and a mixer. So the drummer (our drummer, Marty The Snake) has a remote on his cymbal stand and has control of tops and kick on ch 1 and 2. "

see it in context
The primary advantage of this approach is that with two inputs to a PAS, you have independent control over the relative levels of the top-half of the kit and the bottom (kick). Makes setup very simple. Wiring them out of phase seems to cancel most of the kick drum, which is the predominant signal that both mics pick up. For some reason, it doesn't seem to affect the snare though, which is also picked up by both mics. I'm sure Cliff will explain the theory.

I have a buddy at a local music store that ordered one for me already wired out of phase. I'm sure he would be happy to order some more if anyone is interested. I think it was about $15.

Larry
Here's the nerds view Smile
Wiring the the two mics out of phase creates essentially a "dipole". Everything that is in the middle (i.e. equal distance) between the two microphones will get equally but out-of-phase so it cancels when the two microphone signals are summed together. In essence it creates a "blind spot" for the microphones for whatever is right in the middle plane. For the drums, that's mainly the kick (as Larry pointed out) and also the drummer (when he/she is hemming and hawing, squeaking with the chair, yelling about or in general having a grand old time).
Another nice trick is to place the L1 that gets the mic signal somewhere the middle plane of the microphones. This drastically reduces potential for feedback and unwanted regeneration.
Sound sources that are significantly closer to any one of the microphones are not much affected by the whole procedure.

Hilmar
Thanks Everyone,

I get it now. This is a very responsive community!

Larry (gitarzar) - Yes - I will gladly take you
up on your kind offer to hook me up with some
prewired - out of phase - cables. My email
is carlos@@@@@@@@cadence.com - I'd like 4 them please
and I can paypal you up front with the $$$
for them plus shipping. Just email me your
info + total required.

Thanks!
Carlos

[Steve-at-Bose added extra @@@@ to email address to hide it from spam scraping software]
Carlos,

I'm going to hook you up directly with my friend. His name is Chris Chamis at the Music Loft in Durham, NC, (919) 286-9539. I've already talked to him, he knows what you want, and he's expecting your call. He also said he'd give you the same deal he did for me, which was very good. Good luck.

Larry

[corrected phone number and double sig. LDM]
Hi Jeff,

I have one of these cables that I made myself from 2 mic cords.
If you are handy with a soldering gun, make your own.
Just swap hot & cold leads on one cable before soldering
the cables with the female XLR ends to the single male XLR.

I tried the out-of-phase method three times without spectacular results.
However, I never saw a real picture of where anyone actually "placed" those mics,
so I'm not sure if I did it right.

But I put one to my left, 1' above the floor tom aimed toward
the center of my two rack toms.
The other mic went to my right about 1' above the hi-hat aimed toward
the center of the two rack toms (I realize my description is probably vague too).
I adjusted the aims a few different ways while experimenting.

I guess I was expecting a full tone on the toms that I didn't get.
Was also expecting to really hear something big, but didn't.
Whenever I got the volume to where I could "hear" it, it would feedback.

I have heard others say that it is set up correctly when you "JUST"
begin to hear the drums/cymbals thru the L1.
And that the drums will sound great to the audience,
if not so much to the drummer. Maybe I was expecting too much.

The real question might be the style of music you play and
if the drums really need micing.

Forum poster, starvin007, has had great results with just one overhead mic.
He is an extremely tasteful drummer as well, so that contributes much I'm sure.
He has said that when he just barely hears the drums coming thru the L1 that
it carries well into the audience.
So maybe that is what you need to listen for,
just a hint of the drums thru the L1.
www.audiopile.net is another good source for adpators/cables etc. You can make a out-of-phase adapter by combining these a phase reversal adpator:
http://www.audiopile.net/products/Adaptors_Connectors/A.../CA-301_cutsheet.asp



with an XLR splitter cable:
http://www.audiopile.net/products/Mic_Instr_Cables/MP_A...nd_YMFF_cutsheet.asp

No soldering required. Get the YMFF splitter and connect the phase reversal adaptor to one female end of the splitter. The two femal ends go to the two microphones, the male end to the PS1.


Hilmar

Add Reply

Likes (0)
Post
Having trouble signing in?

We recently updated our sign-in procedure and if you have old sign-in data cached, this can create a problem. Please:

  1. Clear your browser cache and cookies
  2. Then close the browser (not just the window)
  3. Open the browser and try again
Thank you

Please make sure that your profile is up to date
×
×
×
×