weird sound problem

[zac850]

My school has a 16 channel Spirit 8. Today while I was running some mic cables for the talent show tomorrow I was playing the soundtrack to Wicked. I got to the end, and heard 2 vocal lines not come over the sound system. I investigated.

Now, before I go on, I should explain my school's odd sound system. The main out of the spirit board is going in as 2 mic inputs to a powered Peavey board, since we do not have any amps. The main out of that is running around the gym, right next to all of the lighting power cables, and to the speakers. Yes, we have horrible hum. Yes, I am working to get a snake to go under our gym, and yes I am working on getting amps, but for now, it works.

Anyway, back to the problem. I was listening to these lines, and was really confused that I didn't hear these two lines. These lines are high in the vocal range, so I assumed that going through the lines it lost the signal, or that the EQ was set incorrectly. I went into the booth and checked the settings of the sound board. On the Spirit 8 there is a button that you can push to run through the EQ or not, the button was up, so the sound was not running through the boards EQ.

I then checked through the headphones, checking whatever is coming out of the spirit 8 board. I did not hear the lines. I tried the same thing in a different channel, and yet again, did not hear the lines. Does anyone have any idea what could cause this, and why the soundboard does not want to use these sounds? The sound is inputing from my iPod, and I hooked up the headphones directly to the iPod, and it worked fine, so I know it is somewhere in the board.

For those with the Wicked soundtrack, it is "Thank Goodness", starting at about 3:27 minutes in, according to iTunes.

[avkid]

first guess: adjust the eq on your ipod

[mbenonis]

Hmm, after re-reading your post I see that the problem is those last two (high) lines in the song that don't go through. A number of questions: Are you using the headphones jack on the iPod or a line out (say, from the dock)? If it's headphones, what is the volume level on the iPod and the gain set at on the board? How is the iPod connected to the board, XLR or 1/4"? Have you tried connecting the iPod directly to the powered Peavey board to see if it's problem with the Spirit 8?

Edit: Have you tried burning the song to CD and running it off of that? what is the result?

[zac850]

I'm using a headphone jack. I took headphones and played it just through the headphones, and it all came through. Volume on the iPod was at about 60 or 70%. iPod is connected from a headphone out to 1/4 inch into the board. gain on the board is at 0. I have not tried going just into the peavey board.

I used the headphone out of the Spirit board and did not hear the lines, so it must be a problem with the spirit board.

I haven't tried burning a CD, but I'll try doing it tomorrow.

[Peter]

I would try using a different cable between your iPod and your board. When I used my laptop into a sound board I had the same really strange vocal dissappearance when I was using a small guage cable (It was a thin headphone cable with a 1/8th inch plug on each end, with an adapter to 1/4 inch standard audio on the end going into the mixing board.

The fix I will be using tomorow night when I am going to be DJing (see my post elsewhere for more on this) is simply to use a heavier cable between the laptop and mixing board. I stumbled onto this the first time quite by accedent, but now i go from a 1/8th inch (heaphone) output from my external sound card imediately to an adapter that switches it to 1/4 inch. I then use a normal "monster" cable (actually one that is borrowed from a friends electric guitar) to go from that adapter into my mixing board. Problem solved!

Note: the adapter I am talking about is very similar to the one on this page: http://www.trianglecables.com/35minstermal.html although it is not exactly this one.

[Inaki2]

Let me see if I get this right. All the soundtrack is heard except for the last 2 lines?

[Peter]

I think that's right, Inaki2. It sounds really really close to the problem I was having. It seemed like interfearence from the rest of the music (especially base in my case) drowned out / canceled out the vocals. Maybe someone will have a better explanation of why this happens.... I would be VERY interested in hearing why this happens.

[Inaki2]

MM....well, yes, there is a psychoacustic property called frequency masking. Basically above a certain threshold, frequencies will cover up other frequencies.
Its weird that it happened on a recording like that, since someone would've noted it. And it's never so extreme as to completely mask it.
Another posibility is that if you were inputing it thru an unbalanced 1/4" input, and using a TS jack in the console end, you had phase cancellation due to the vocal being mixed in mono and the balancing circitry flipped the phase on your vocals. I've had this happen before. Its kinda weird sounding, as you only hear the reverb which is in stereo.

[DMXtools]

Originally Posted by Inaki2

Another posibility is that if you were inputing it thru an unbalanced 1/4" input, and using a TS jack in the console end, you had phase cancellation due to the vocal being mixed in mono and the balancing circitry flipped the phase on your vocals. I've had this happen before. Its kinda weird sounding, as you only hear the reverb which is in stereo.

More likely, to make the vocal sound distant, it may have been put on the two channels out of phase in the original recording. Through stereo headphones or speakers it's great, but mixing it down to mono, the out-of-phase vocals cancel.

John

[Peter]

I am just home from tonights gig, and I really quickly tested it out, and had the same type of vocal problem when using a thinner headphone type cable. I switched it to the heaver cable and it worked fine for the rest of the night.

Random comment:I should have gotten pics of the whole setup tonight, I was running from my laptop into a mixer then from that into a mixer->amp chain for the gym's built in speakers, and also from the primary mixer into a PA system type mixer that powered 6 aditional speakers (nearly all the speakers from our auditorium, including the monitors) I had an Aux out of the mixer in to a friends laptop's Mic In port, and had that laptop runing g-force (a cool free visualization program) through a projector. This projector was aimed through a blanket of rising fog that I chilled in a homemade custom fog chiller, so the fog rolled allong the ground out of a cemetary scene that had been made, when it left the cemetary the smoke drifted up into the beam of the projector making a REALLY neat effect. All together it was probabaly the neatest dance in our school's history.

Anyway, now that I am WAY off topic, I got the whole rig working with decent sound quality by using heavy 1/4 inch cable on every connection.